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Quasi
2002-Nov-14, 01:50 AM
Well this is suprising. Today in my Communications class we had a group excersize, the excersize was this test:

___________________________________________


You are part of a spcae crew originally scheduled to rendezvous with a mother ship on the lighted surface of the moon. Due to mechanical difficulties, however, your ship is forced to land at a spot some 200 miles from the rendezvous point. During the reentry [would it even be considered reentry in a lack of atmosphere? -Quasi] and landing, much of the equipment aboard was damaged and since survival depends on reaching the mother ship, the most critical items availible must be chosen for the 200 mile trip. Below are listed the 15 itemsleft intact and undamaged after landing. Your task is to rank order them in terms of their importance in allowing your crew to reach the rendezvous point. 1=most important 15=least important.


___Box of matches
___Food Concentrate
___50ft of nylon rope
___Parachute silk
___Portable heating unit
___Two .45 Cal pistols
___One case dehydrated milk
___Two 100lb. tanks of oxygen
___Stellar Map (of the Moon's constellations)
___Life raft
___Magnetic compass
___5 Gallons of water
___Signal flares
___First-aid kit containing injection needles
___Solar-powered FM reciever-transmitter




____________________________________________

Anyhow, thats the test we were given to first complete individually, and then in groups of four. I'd love to hear some of your answers. Afterwards I'll post the ones my group got and why.

Another thing, any truth this being an actual NASA test? A couple things about it make me think not.......


Edit: WHOOPS! Completely forgot 2 of the choices. I Swore I proof-read that list twice.... Anyway fixed now.

<font size=-1>[ This Message was edited by: Quasi on 2002-11-14 02:42 ]</font>

g99
2002-Nov-14, 03:05 AM
On 2002-11-13 20:50, Quasi wrote:
Well this is suprising. Today in my Communications class we had a group excersize, the excersize was this test:

___________________________________________


You are part of a spcae crew originally scheduled to rendezvous with a mother ship on the lighted surface of the moon. Due to mechanical difficulties, however, your ship is forced to land at a spot some 200 miles from the rendezvous point. During the reentry [would it even be considered reentry in a lack of atmosphere? -Quasi] and landing, much of the equipment aboard was damaged and since survival depends on reaching the mother ship, the most critical items availible must be chosen for the 200 mile trip. Below are listed the 15 itemsleft intact and undamaged after landing. Your task is to rank order them in terms of their importance in allowing your crew to reach the rendezvous point. 1=most important 15=least important.


_12__Box of matches umm...no air on the moon
_3__Food Concentrate mmmmm...Donuts
__7_50ft of nylon rope (imagine tarzan yell then THUMP as run into rock cliff)
_8__Parachute silk Geronimooooo!!...
_11__Portable heating unit what will it heat? no air to conduct it to your body
_10__Two .45 Cal pistols Will this work in a oxygenless atmosphere? (i really am asking this)
_6__Stellar Map (of the Moon's constellations)arn't they the same as the earths?
_9__Life raft to prtect from the sun?
_1__Magnetic compass of course!!!
_2_ 5 Gallons of water mmmmm...Water
_12__Signal flares again no air to burn them with
_5_First-aid kit containing injection needles Drugs are bad!
_4__Solar-powered FM reciever-transmitter "Huston we have a problem..."




____________________________________________

Anyhow, thats the test we were given to first complete individually, and then in groups of four. I'd love to hear some of your answers. Afterwards I'll post the ones my group got and why.

Another thing, any truth this being an actual NASA test? A couple things about it make me think not.......


i remember this test i grade school (so not to decieve you, i'm 21. It was over 10 years ago i took it, and for me that is a long time ago./phpBB/images/smiles/icon_smile.gif) It is a very old test. /phpBB/images/smiles/icon_smile.gif When i ttok the test we also had the option to take the door from out ship. My answers are included (plus stupid comments)....
P.S. there are only 13.

_________________
"I am not conceited, i'm perfect"
"It takes Thousands to fight a battle for a mile, Millions to hold an election for a nation, but it only takes One to change the world." by Dan Sandler 2002

<font size=-1>[ This Message was edited by: g99 on 2002-11-13 22:55 ]</font>

John Kierein
2002-Nov-14, 03:15 AM
no magnetic field on the moon

nebularain
2002-Nov-14, 03:28 AM
I'm with g99 - this test is a bit ridiculous. Even practical stuff like food and water won't do you any good if you are traveling by foot in a space suit! (Unless you could carry them inside your suit, and the suit has enough space inside for you to move your arm out of the sleeve to move the food from the "pocket" to your mouth /phpBB/images/smiles/icon_razz.gif .)

Irishman
2002-Nov-14, 03:34 AM
Not likely. At least I've never encountered it. It is a thinking and problem solving excercise, not really something to solve. Plus, there are a dozen useless items for a moon landing.

And your questioning of the terms in the question was good, too.

_1__Solar-powered FM reciever-transmitter

Duh, this is your communication gear, to call for help.

_2__5 Gallons of water

200 miles is along way to walk, even on the moon

_3__Stellar Map (of the Moon's constellations)

Which would be the same as Earth's constellations. But it would be nice to have the reference to find your way.

_4__Food Concentrate

200 miles is a long hike, even on the moon /phpBB/images/smiles/icon_wink.gif

_5__Signal flares

Get attention if someone is looking for you and comes close

_6__50ft of nylon rope

Maybe this could be used for something. Can't think of anything offhand, but rope is rope.

The rest of it is crap. Useless. Wouldn't bother with it.

Matches? No air.
parachute silk? No air. I suppose a makeshift tent, but when are you going to run out of air?

Portable heating unit? You're in the sun.
Pistols? Pistols? Unless the Moon is suddenly a penal colony, what are you defending yourself from, mountain lions?
Life raft? WTH?

magnetic compass - trick item. On the moon it would be useless.
First aid kit - unless it has space suit patches (maybe tape?), it's useless. You're in your space suit, remember?

It looks like someone converted an old question from a sea voyage to a moon trip. These look like items collected from a ship or plane wreck and you're stuck on an island in the Pacific.

g99
2002-Nov-14, 03:58 AM
It should be updated to landing on a alien planet. It would make much more sense(plus be more fun and imaginative). You can next have the kids use thier knowledge of animals alive today to make realistic aliens that they will encounter. Either way it is a great critical thinking project.

Duane534
2002-Nov-14, 04:03 AM
Box of matches? No. (obviously)
Food Concentrate? Depends on how long you plan on staying
50ft of nylon rope? Probably not. Remember: 1/6 G
Parachute silk? Useless w/o air
Portable heating unit? Useless w/o air
Two .45 Cal pistols? Useless w/o air
Stellar Map? (of the Moon's constellations) Sounds good, except it would be pretty erratic w/ one more orbit to account for
Life raft? We're past Galileo. We know they aren't seas
Magnetic compass? No magnetic poles
5 Gallons of water? Better be temp. controlled
Signal flares? Useless w/o air
First-aid kit containing injection needles? Why would you need to inject anything? Interstellar flu?
Solar-powered FM reciever-transmitter? Maybe, but that should already be on your suit.

aporetic_r
2002-Nov-14, 04:50 AM
There are those who claim that the life raft is important because you will need something in which to carry all the other stuff. That said, it is a silly test anyway, because (as someone has already said) you can neither eat nor drink in a spacesuit.

Quasi
2002-Nov-14, 08:03 AM
A few points...

1. Most signal flares can work without oxygen. The chemicals within release oxygen as they burn, completely eliminating the need for them to be in an oxygenated environment.

2. I think it would be safe to assume that with this seemingly being in some sort of future setting it would be possible to consume some sort of specially prepared and packaged food and water in some way through a suit (mini air-locks anyone?).

3. I assume that a firearm could work since the bullet is air-tight and contains enough oxygen to start the explosion but I also assume that external air helps continue the chemical reaction after the bullet leaves the casing. If this is the case a bullet would still work, but be less effective (not counting the fact there would be no air resistance).

Also the reason for there being matches and other things that are equally useless is because this test seems to be used with a group of mostly lay people so that they can combine their knowledge to create a halfway-decent prioritized list.

As an example of what I mean, take about 20 people off the street and give them the test individually and most would probably put things like matches within the top 5. Now put those 20 people into groups of 4 and re-do the list and you would get much better results (probability saying that at least one person in each group would realize that the lack of oxygen seriously hampers things). Don't forget, the test is more of a group-building exercize than a space-physics quiz. I deiced to post it here to see how non-lay people would answer. Well that and to determine if my instructor's statement about this being administered to potential NASA employees is even remotely true (currently I'm still convinced it's not but if someone with NASA work experience wants to prove me wrong....).

Overall though some very good and very interesting answers.

____________________________________________

The original post above has been fixed to add the 2 missing items, sorry about that.

<font size=-1>[ This Message was edited by: Quasi on 2002-11-14 03:09 ]</font>

David Hall
2002-Nov-14, 09:10 AM
I think that it's pretty obviously an older shipwreck-type test put into a new setting. Otherwise there would have been more logic to the choices made. Of course there would still have to be a few spurious items included, but the useful ones would be more fitting for the situation.

I also agree it would be better to put it on some alien world. The airless surface of the Moon is something a lot of people just have no real conception of. But a plantetary environment with life, even if it was completely alien, at least has a few elements that people can relate to. Weather, terrain, plant and animal life (even if unfamiliar), day and night. I think the answers given would be both more realistic and more interesting.

gbaikie
2002-Nov-14, 11:25 AM
On 2002-11-13 20:50, Quasi wrote:
Well this is suprising. Today in my Communications class we had a group excersize, the excersize was this test:

___________________________________________


You are part of a spcae crew originally scheduled to rendezvous with a mother ship on the lighted surface of the moon. Due to mechanical difficulties, however, your ship is forced to land at a spot some 200 miles from the rendezvous point. During the reentry [would it even be considered reentry in a lack of atmosphere? -Quasi] and landing, much of the equipment aboard was damaged and since survival depends on reaching the mother ship, the most critical items availible must be chosen for the 200 mile trip. Below are listed the 15 itemsleft intact and undamaged after landing. Your task is to rank order them in terms of their importance in allowing your crew to reach the rendezvous point. 1=most important 15=least important.


___Box of matches
___Food Concentrate
___50ft of nylon rope
___Parachute silk
___Portable heating unit
___Two .45 Cal pistols
___One case dehydrated milk
___Two 100lb. tanks of oxygen
___Stellar Map (of the Moon's constellations)
___Life raft
___Magnetic compass
___5 Gallons of water
___Signal flares
___First-aid kit containing injection needles
___Solar-powered FM reciever-transmitter




____________________________________________

Anyhow, thats the test we were given to first complete individually, and then in groups of four. I'd love to hear some of your answers. Afterwards I'll post the ones my group got and why.

Another thing, any truth this being an actual NASA test? A couple things about it make me think not.......


Edit: WHOOPS! Completely forgot 2 of the choices. I Swore I proof-read that list twice.... Anyway fixed now.

<font size=-1>[ This Message was edited by: Quasi on 2002-11-14 02:42 ]</font>


Well, you don't list any spacesuits, so unless you can make one, you aren't going anywhere. You would stay put if there wasn't spacesuits or there was a possible rescue- but if you could travel and needed to. First you would use star charts to determine where you were and which direction to mothership. Stars aren't going to change in time you need to get to mothership, so you simply need to pick one star you will head towards it [near horizon]. So you don't need to take charts with you.
What else you take, depends on what kind of spacesuit you have. Does it need the water to keep you cool, does it need extra oxygen, and how mobile are you in the spacesuit- how heavy is it, how flexible is it which will ultimately determines how many miles you could travel per hr. You could have capability of being able to travel in the range of 1 to 20 mph, meaning from +200 hrs to +10 hours. If it's +200 hrs, you probably don't have enough oxygen, if it will take around 10 hrs, you don't need to bring any food. You will need the oxygen and water for drinking. Another factor is the terrian you are going to go through- rough terrian will slow you down. 50' of rope probably wouldn't be enough length to be helpful for climbing down cliffs and if the terrian is so bad that you need to spend time climbing down cliffs you probably aren't going to have enough time to travel the 200 miles.
So, you need a good spacesuit and enough oxygen to breath and enough water to drink for say about 24 hrs of travel. If it likely to take 2 or more days, I don't think you will have enough oxygen.

Jim
2002-Nov-14, 06:04 PM
There are several variations of this exercise... life boat, desert, arctic... all thought up by leadership training types. They are intended to demonstrate that a group working for consensus can reach better decisions than an individual acting alone (unless the individual is an expert in that area).

Tell your teacher you want to build a Space Tower next.

ToSeek
2002-Nov-14, 06:08 PM
Yeah, I had to do the same exercise in a business management class over 20 years ago. It's been around for a while.

daver
2002-Nov-14, 07:22 PM
> Yeah, I had to do the same exercise in a business management class over 20 years ago. It's been around for a while. <

Quite a while. I remember it from jr high school. 30+ years.

honestmonkey
2002-Nov-14, 09:53 PM
I remember if from high school (or earlier) as well, about 30 years ago. This was a "landing out in the middle of the desert" scenario.

While I can't think of why you'd want matches on the moon, it's possible you could make something out of them. Tie the oxygen tanks together with the rope, open the valves and strike a match, instant rocket (or maybe bomb?).

Seems like things would be set up so that the base would be tracking you and would be able to mount a rescue. My understanding, at least on Earth, is that it is better to stay where you are and get found, rather to wander off and get even more lost.

Smaug
2002-Nov-15, 01:03 AM
First of all, as said before it would be cooler if it was on an alien planet. One main reason I can think of, practical use of the guns. /phpBB/images/smiles/icon_lol.gif Also, yes I believe the flares would work (also said before) because they don't really need oxygen, they burn with the part in the stick. You know, the ones that burn underwater? About the guns. Wouldn't the bullets go even faster? No outside pressure means that the gas would want to shoot out extremely fast, presuming that the gap between the bullet and barrel is very thin, or non-existant. However if the pressure is that great, the gun might backfire and blow shrapnel into your visor (OUCH !!!). Well that's my input.

Smaug
2002-Nov-15, 01:09 AM
Also, another thing about the gun. Why would you need a gun to kill someone on the Moon. Just poke 'em with a pin! /phpBB/images/smiles/icon_lol.gif As to the reason why it's on the Moon and not on a desert isle or something. I think that after the Moon landings, everyone got Moon-Hype ( /phpBB/images/smiles/icon_smile.gif ) so they decided that people would be more interested with it, if it involved the Moon?

mallen
2002-Nov-15, 01:38 AM
If you happen to be on the Earth-side of the moon, you probably wouldn't need the star-chart. The earth kinda just sits there in the same place in the sky, so you could use it for directions.

Of course, if you were on the far side (not the dark side /phpBB/images/smiles/icon_smile.gif the star chart would be more useful.

r0ck3t
2002-Nov-15, 01:58 PM
I noticed no one want's to take the guns. "They would be useless" to paraphrase. C'mon guys, use your imagination. You could (theoretically) use them for propulsion. Think of it as an impulse engine. Maybe you could jump and shoot backwards to give you a kick. Or maybe you could point it downards a little to keep you off the surface too. It would probably be hard to line up the thrust with your CG, but it sure would be fun to try. /phpBB/images/smiles/icon_smile.gifLOL:)

Smaug
2002-Nov-15, 10:25 PM
Or perhaps you could shoot your fellow astronauts in the foot and see what happens? Evil, I know /phpBB/images/smiles/icon_lol.gif.

Ilya
2002-Nov-16, 12:01 AM
My daughter is in 5th grade, and she got that test a few weeks ago - with a small twist. Parachute was removed, and compressed air tanks added.

Colt
2002-Nov-16, 01:44 AM
I got this test a while back too, I was the only one screaming about how stupid it would be to even have this stuff with you.

___Box of matches - Like mentioned above you could possibly use this with one of the oxygen tanks to create a rocket, not sure if pure oxygen, in a vacuum would burn though, it might instantly flash to oxygen ice.

___Food Concentrate - Unless you had a way to get it into your suit, useless.

___50ft of nylon rope - If you ripped your suit, on your leg or arm, you could use this to tie that section off, otherwise not really useful (any 45ft (you would need line to tie it) drop you could just drop off, it would only be about 7.5 feet).

___Parachute silk - You could possibly use this in conjunction with the rope to seal a tear in your suit, I don't know if the silk would be dense enough to stop air from escaping though.

___Portable heating unit - Junk it unless you can hook it up to your suit somehow, though your suit would already have a heater.

___Two .45 Cal pistols - I assume that by the time they have something like a "mothership" on the moon, they would not use gunpowder anymore. You could use them for propulsion, jump and fire them, though it might send you up only three feet then back down. They would have a higher muzzle velocity since there would be no outside pressure to stop the gasses from expanding, and no air for resistance.

___One case dehydrated milk - Useless.

___Two 100lb. tanks of oxygen - If you could resupply your own tank with this then keep it. You could also shoot off (with the pistols) the valve on it and use the oxygen for propulsion (you would not have to light it even).

___Stellar Map (of the Moon's constellations) - This might be useful, if you knew how to use it (I doubt any Apollo astronauts would have known how).

___Life raft - Why would you have this along with the matches in the first place? If it was inflated, it would explode as soon as you exposed it to the vacuum. You could use it drag all of your stuff (use the rope for a harness) but it would slow you down and even the "100 pound" O2 tanks would only way aaround 17 pounds, each.

___Magnetic compass - You could use the glass on it to reflect light at a passing space-liner. /phpBB/images/smiles/icon_biggrin.gif Seriously, in the first place you would most likely have an electronic compass, for use on the earth only.

___5 Gallons of water - If it was compressed you might be able to use it for propulsion, same way as the 02 tanks. Maybe you could use the power source from the heater (mini-nuke!) to electrolyze the water, create a rocket engine using parts from your crashed ship, and just fly. /phpBB/images/smiles/icon_smile.gif

___Signal flares - Most modern flares can burn completly underwater so I assume they would burn in a vacuum . You could use them to light the 02 tank or the proposed rocket engine, maybe even blow yourself up. You might even use them for their intended purpose, as a flare. /phpBB/images/smiles/icon_razz.gif

___First-aid kit containing injection needles - It all depends on what is in it, and if you tried to inject yourself through your suit you would probably be worse off with the hole.

___Solar-powered FM reciever-transmitter - Must have, probably the only really useful thing on this entire godforsaken list.



You could, of course, just die and get it over with. -Colt

David Hall
2002-Nov-16, 03:06 AM
On 2002-11-15 08:58, r0ck3t wrote:
I noticed no one want's to take the guns. "They would be useless" to paraphrase. C'mon guys, use your imagination. You could (theoretically) use them for propulsion. Think of it as an impulse engine. Maybe you could jump and shoot backwards to give you a kick. Or maybe you could point it downards a little to keep you off the surface too. It would probably be hard to line up the thrust with your CG, but it sure would be fun to try. /phpBB/images/smiles/icon_smile.gifLOL:)


I must disagree here. I really can't think of anything useful about the pistols. Their only purpose is to make holes at things from a distance. What good is that? If you need to make a hole in one of your possesions, there are better tools for that. As a signalling device? No air means no sound, so the only way to get somone's attention with them would be to put a hole in him. They aren't even good for propulsion. Guns can throw their projectiles great distances because the bullets have so little mass. Try to do the same thing with a fully-suited astronaut and the only thing you might do is knock him off his feet. You'd need a continuous stream of bullets to provide any meaningful thrust.

Colt's comments above on the uselessness of just about everything on the list is dead-on. Just about everything on that list is total garbage except the oxygen and the radio, and possibly the rope. There's one thing I'd like to add about the inflatable raft. If you use it to drag stuff behind you, then unless it's made of some wonder material it's going to get worn right through in no time flat. Useless.

David Hall
2002-Nov-16, 03:14 AM
Ok, now that we've throroughly trashed the list as given, how about writing up a list of things that really could be useful? Or at least trying to update this test with some more realistic items? How about writing up an alien planet version as well?

daver
2002-Nov-16, 03:26 AM
I think the short answer is that if you have to walk the 200 miles you're hosed. So let's assume you do the sensible thing and stay in one place. In that case two of you can go outside and make arrows with the powdered milk and the parachute so the rescue ship has an easier job of finding you.

If you have to walk, it's going to take on the order of 10 days (20 miles/day seems fairly reasonable given the cumbersome lunar suit, maybe you could go faster. If this situation ever occurred the captain would have a better idea). Anyway, one person uses perhaps 10 lbs of O2 a day. So you have enough air for two people to survive the journey. So the first thing you do is grab the pistols and shoot everyone except someone who can also do arithmetic. Then maybe you and your crony can cart out all the useful items (and maybe use the box of matches to set a fire to blow up the wreckage).

___Box of matches - Use to destroy evidence.

___Food Concentrate - 10 days--figure some way of taping some inside your helmet if it doesn't come with a dispenser.

___50ft of nylon rope - Use it to tie the rest of your equipment together.

___Parachute silk - Might be useful for making a shelter.

___Portable heating unit - I don't see how this can be useful. Maybe the power pack in it could be good for something.

___Two .45 Cal pistols - Empty, or nearly so. Keep them so your partner doesn't get one. Maybe you can hide the evidence sometime.

___One case dehydrated milk - Maybe still good for a marker.

___Two 100lb. tanks of oxygen - Absolutely necessary.

___Stellar Map (of the Moon's constellations) - As opposed to the Earth's constellations? Maybe it could be used for navigation, probably not. On the other hand, it doesn't weigh anything. On the other hand, you might have already used it when you torched the ship.

___Life raft - Maybe the inflator cartridges could be useful. Maybe the raft has a locator beacon. Maybe you can cut it up to repair damage to your suit. Most likely it's junk.

___Magnetic compass - Junk

___5 Gallons of water - 10 days. I'm not sure it's enough for two people, but it's better than nothing.

___Signal flares - May be useful in torching the wreckage.

___First-aid kit containing injection needles - If all it has are injectable drugs and the needles aren't compatible with the suits, forget it. Well, maybe you could use it instead of shooting your crew--dope them all up on morphine (under threat of the guns). That way there won't be the incriminating bullet holes. Then break out a porthole so it looks as if the ship lost pressure in the crash and your crew were too stupid to wear their suits. That way you might not have to torch the wreckage.

___Solar-powered FM reciever-transmitter - Well, less useful if it doesn't have mic/headphone jacks compatible with your suit, but i'll assume it does.

OK, so we can use a number of the items to kill off most of the crew and conceal the evidence. As for the rest, take the oxygen, the water, the radio, the rope, the food, the parachute, the flares. I'm not sure of the star charts--if or your crony know how to use them, take them. They're light.

Colt
2002-Nov-16, 07:31 AM
I think it is implied that you are alone, or you could just use your crewmates as packmules and take it all. I think that we should make up a list of stuff to have.

1. Emergency beacon.
2.Emergency oxygen and water.
3. "Liquid food" packs for your suit.
4. Small nuclear device to signal to someone in England, or just some normal flares.
5. Radio.

What do you take? None of it. Just sit with your ship's wreckage, sipping your liquified--fried-chicken and wait. -Colt

g99
2002-Nov-16, 07:55 AM
For a alien planet:
Assuming earth like temps and atmosphere.

1. Box of matches and a flint kit.
2. Laser gun with solar rechargable pack (you would run out of bullets really fast if alone and also if you are on a alien world i would imagine you had lasers.)
2. armored collapsable geodesic dome for you and your stuff. Protected from harsh winds and animals.
3. Backpack with hard liner for comfort and support along your spine.
4. Food and water. If there is water on the planet replace water with small canteen and a water purifyer machine.
5. Hopefully your portable emergency radio survived, if not read on....
6. a heck of alot of luck.
7. a good book. If you are on an alien planet and have no signaling device, well have a good life because you are out of luck.
8. A good Camera. You will probobly see some really cool stuff and wildlife. Record it blair witch style for future explorers.

Irishman
2002-Nov-16, 02:57 PM
I will admit for food and water I assumed they were compatible with the space suit. I also assumed you had a space suit. And oxygen wasn't on the list when I read it.

The pistols would work, as pistols; the gunpowder includes its own oxidizer. But they are useless unless you don't trust your partner. Or expect to encounter "bad guys" between the crash and your mother ship.

Okay, the raft might have some use as either a sled or as possible emergency patches. Got a roll of duct tape? /phpBB/images/smiles/icon_wink.gif

I suppose the parachute could be rigged to make some sort of backpack to help carry all your stuff.

Smaug
2002-Nov-16, 05:56 PM
We shouldn't say it's ALL useless. I mean come on, we could even use the raft for something! Just wear it as a suit so you stand out. /phpBB/images/smiles/icon_lol.gif ... hmm or you look like a weird space alien and the mothership shoots you.

<font size=-1>[ This Message was edited by: Smaug on 2002-11-16 12:57 ]</font>

bArt2
2002-Nov-16, 07:19 PM
I would say this

1. Two 100lb. tanks of oxygen
2. 5 Gallons of water (not sure how to get it inside the suit)
3. Food Concentrate (same remark)
4. Stellar Map of the Moon's constellations (for navigation)
5. Solar-powered FM reciever-transmitter
6. Signal flares
7. Life raft
8. 50ft of nylon rope (use 7 and 8 to transport your stuff)
9. Parachute silk (maybee you can use it as cover for rays while eating/drinking or make a tent)
10. Portable heating unit (for use inside tent)
11. Box of matches (there is nothing to burn, maybee needed to light heating unit)
12. First-aid kit containing injection needles
13. One case dehydrated milk
14. Two .45 Cal pistols (are there any Marsians to shoot??)
15. Magnetic compass (where is north? use stellar map)


<font size=-1>[ This Message was edited by: bArt2 on 2002-11-16 14:24 ]</font>

Colt
2002-Nov-16, 08:24 PM
I don't think that we can really make up our own list, otherwise we would just have the stuff we would need, and no junk, unless we included it on purpose just to screw the layman up. Still, comparing two items, on our supposed list, what would be more valuable? A box of twinkies or a Radio Isotope Thermo-electric Nuclear Generator.

-Colt

Smaug
2002-Nov-16, 08:36 PM
I would prefer a Snickers Cruncher myself.

g99
2002-Nov-16, 08:37 PM
On 2002-11-16 15:24, Colt wrote:
I don't think that we can really make up our own list, otherwise we would just have the stuff we would need, and no junk, unless we included it on purpose just to screw the layman up. Still, comparing two items, on our supposed list, what would be more valuable? A box of twinkies or a Radio Isotope Thermo-electric Nuclear Generator.

-Colt



No contest, the twinkies!!!

With a little duct tape and some string you can make anything out of them.

They have so many chemicals in them, you can probobly make a nuclear reactor out of one of them also. /phpBB/images/smiles/icon_smile.gif

Quasi
2002-Nov-18, 05:23 AM
OK, these are the "correct" answers I was given along with the explination of thier importance. Needless to say I disagreed with a few of them... My group's answers are in brackets and, my personal comments in italics.



13 [15] Box of matches | Useless
Then why 13 instead of 15?

3 [4] Food Concentrate | Nutrition

5 [7] 50ft of nylon rope | To tie your teammates together.
What the.... are you climbing Mount Everest now? Though I do suppose some of the larger craters you would have to climb in/out of if they're too big to go around

11 [10] Parachute silk | Shelter from the Sun I said possible patching material

6 [12] Portable heating unit | Warmth and can also be dissasembled to create power unit
To power what?!? And heat? I tried to explain to my teacher that you would get very little heat from a heater without an atmosphere to conduct most of the heat but I was ignored and glowerd at.

14 [14]Two .45 Cal pistols | Can be used for possible propulsion but overall too dangerous to rely on.
Yes, but only if you aim at someone. Any why in the world was this ranked lower than the matches considering that they have fewer practical uses? I brought that up but was proptly ignored.

10 [9] One case dehydrated milk | Additional Nutrition

1 [1] Two 100lb. tanks of oxygen | Well duh

4 [5] Stellar Map (of the Moon's constellations) | Navigation

9 [11] Life raft | To haul equipment
Good call on this one everyone, I never even considered that. I thought that was the entire purpose of pack-mu... errr teammates.

15 [13] Magnetic compass | No magnetic field on Moon
Yes but if you have MacGuyver on your team to dissasemble that heating unit and then take the compass needle he can make a coconut radio! Sorry, still bitter about that.

2 [3] 5 Gallons of water | To combat the evil forces of dehydration!

12 [6] Signal flares | Useless unless close The heck? Where is the logic there? If that's the case then why do we use them on Earth? And yet they only score one point above matches....

7 [8] First-aid kit containing injection needles | Can't remember the value she said about these
I also told my instructor that injection needls wont work unless there is air pressure to push the fluid into the syringe but, you guessed it, ignored

8 [2] Solar-powered FM reciever-transmitter | FM transmissions are relatively short on a sphere since the ground can block FM transmissions.
This one totally skipped my mind. Also, since the Moon has a smaller circumference the useful distance of an FM radio is less than that of Earth.


Anyhow, those are the answers my instructor claims "came strait from NASA". Oh Lord I hope she's a liar....



<font size=-1>[ This Message was edited by: Quasi on 2002-11-18 00:34 ]</font>

Kaptain K
2002-Nov-18, 03:12 PM
8 [2] Solar-powered FM reciever-transmitter | FM transmissions are relatively short on a sphere since the ground can block FM transmissions.
This one totally skipped my mind. Also, since the Moon has a smaller circumference the useful distance of an FM radio is less than that of Earth.
AM and shortwave radios achieve long distance by bouncing off the ionosphere. The Moon has no ionosphere, so any radio (not just FM) is limited to line of sight.

_________________
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<font size=-1>[ This Message was edited by: Kaptain K on 2002-11-18 10:14 ]</font>

r0ck3t
2002-Nov-18, 09:06 PM
On 2002-11-15 22:06, David Hall wrote:
I must disagree here. I really can't think of anything useful about the pistols. Their only purpose is to make holes at things from a distance. What good is that? If you need to make a hole in one of your possesions, there are better tools for that. As a signalling device? No air means no sound, so the only way to get somone's attention with them would be to put a hole in him. They aren't even good for propulsion. Guns can throw their projectiles great distances because the bullets have so little mass. Try to do the same thing with a fully-suited astronaut and the only thing you might do is knock him off his feet. You'd need a continuous stream of bullets to provide any meaningful thrust.

Colt's comments above on the uselessness of just about everything on the list is dead-on. Just about everything on that list is total garbage except the oxygen and the radio, and possibly the rope. There's one thing I'd like to add about the inflatable raft. If you use it to drag stuff behind you, then unless it's made of some wonder material it's going to get worn right through in no time flat. Useless.



Wow! You must be some kind of genius or something!:roll:

I certainly wasn't being serious. The point I wanted to make, but obviously didn't do a very good job of, was that with a little thought you probably could utilize several of the items on the list that other people would immediately assume to be useless. With that said, let's look at the conservation of momentum of the bullet/astronaut system.

(Please note, we will be approximating, which may be a stretch for some.)
The average mass of a .45 caliber slug is about 0.25kg. The muzzle velocity of a Colt 1911 is about 253 m/s. I'll say the astronaut has a mass of 200 kg (that may be a bit high, but like I said, we're approximating). Knowing that momentum (P) = mass (m) * velocity (v) and that the total momentum of the system cannot change then just after the gun is fired TotalP = mv1 + mv2 = 0, or -m1v1 = m2v2. If we take v2 to be the astronauts resulting velocity, v2 = -m1v1/m2. So the astronauts initial velocity would be about 0.316 m/s, definatly not enough to get off the ground.

I would figure out what initial velocity the astronaut would have to have to get off the ground and cover some appreciable distance, but I'm tired of typing (not to mention I need to get going), I think I will leave that excercise for someone else.

Later.

SeanF
2002-Nov-18, 09:37 PM
On 2002-11-18 16:06, r0ck3t wrote:

(Please note, we will be approximating, which may be a stretch for some.)
The average mass of a .45 caliber slug is about 0.25kg . . .


Dude, that's a d**n big bullet. IIRC, a .45 slug is 230 grains, which would be about .015kg.
/phpBB/images/smiles/icon_smile.gif

_________________
SeanF

<font size=-1>[ This Message was edited by: SeanF on 2002-11-18 16:38 ]</font>

SpacedOut
2002-Nov-18, 09:43 PM
On 2002-11-18 16:37, SeanF wrote:


On 2002-11-18 16:06, r0ck3t wrote:

(Please note, we will be approximating, which may be a stretch for some.)
The average mass of a .45 caliber slug is about 0.25kg . . .


Dude, that's a d**n big bullet. IIRC, a .45 slug is 230 grains, which would be about .015kg.
/phpBB/images/smiles/icon_smile.gif

_________________
SeanF

<font size=-1>[ This Message was edited by: SeanF on 2002-11-18 16:38 ]</font>


Yeah, but just imagine the stopping power of a hand gun with a 0.25kg round. /phpBB/images/smiles/icon_biggrin.gif

traztx
2002-Nov-18, 09:56 PM
I wonder... if the life raft was reinforced with the rope could you store extra oxygen in it. Probably not much without popping it.

Matches and gun might be useful when you run low on air and you have to "draw straws" to see who gets the bullet.

The flare might be useful if a tank valve gets frozen and you need to heat it up or something.

The radio might be useful for contacting someone in orbit, who could relay info to the receiving party or coordinate them meeting you half way.

JS Princeton
2002-Nov-18, 10:06 PM
Quasi, you are obviously smarter than your teacher and proving that you are to him or her will probably only make things worse.

I think you got a little too hot under tha collar about the heating element. Indeed, radiative heat can be transfered through a vacuum. I don't know what kind of heating element is built, but it could very well provide warmth if its primary energy generation went into creating appropriate wavelength photons.

<font size=-1>[ This Message was edited by: JS Princeton on 2002-11-18 20:06 ]</font>

Smaug
2002-Nov-18, 10:48 PM
On 2002-11-18 16:06, r0ck3t wrote:


On 2002-11-15 22:06, David Hall wrote:
I must disagree here. I really can't think of anything useful about the pistols. Their only purpose is to make holes at things from a distance. What good is that? If you need to make a hole in one of your possesions, there are better tools for that. As a signalling device? No air means no sound, so the only way to get somone's attention with them would be to put a hole in him. They aren't even good for propulsion. Guns can throw their projectiles great distances because the bullets have so little mass. Try to do the same thing with a fully-suited astronaut and the only thing you might do is knock him off his feet. You'd need a continuous stream of bullets to provide any meaningful thrust.

Colt's comments above on the uselessness of just about everything on the list is dead-on. Just about everything on that list is total garbage except the oxygen and the radio, and possibly the rope. There's one thing I'd like to add about the inflatable raft. If you use it to drag stuff behind you, then unless it's made of some wonder material it's going to get worn right through in no time flat. Useless.



Wow! You must be some kind of genius or something!:roll:

I certainly wasn't being serious. The point I wanted to make, but obviously didn't do a very good job of, was that with a little thought you probably could utilize several of the items on the list that other people would immediately assume to be useless. With that said, let's look at the conservation of momentum of the bullet/astronaut system.

(Please note, we will be approximating, which may be a stretch for some.)
The average mass of a .45 caliber slug is about 0.25kg. The muzzle velocity of a Colt 1911 is about 253 m/s. I'll say the astronaut has a mass of 200 kg (that may be a bit high, but like I said, we're approximating). Knowing that momentum (P) = mass (m) * velocity (v) and that the total momentum of the system cannot change then just after the gun is fired TotalP = mv1 + mv2 = 0, or -m1v1 = m2v2. If we take v2 to be the astronauts resulting velocity, v2 = -m1v1/m2. So the astronauts initial velocity would be about 0.316 m/s, definatly not enough to get off the ground.

I would figure out what initial velocity the astronaut would have to have to get off the ground and cover some appreciable distance, but I'm tired of typing (not to mention I need to get going), I think I will leave that excercise for someone else.

Later.


I didn't think that they recruited 400 lbs. astronauts. Hmm plus he's on the Moon, so I'd say he weighs about 2,400 lbs. on Earth.

<font size=-1>[ This Message was edited by: Smaug on 2002-11-18 17:55 ]</font>

daver
2002-Nov-19, 12:03 AM
On 2002-11-18 16:56, traztx wrote:
I wonder... if the life raft was reinforced with the rope could you store extra oxygen in it. Probably not much without popping it.


And you have to match fittings to your tank. Without duct tape, probably not possible. However, it might have a beacon inside it, possibly some sort of flashing light.




Matches and gun might be useful when you run low on air and you have to "draw straws" to see who gets the bullet.



If you have a 10-man crew and a 10-day trek, this will be immediately. Whoever isn't holding the guns, draw matches. Unless two different people are holding the guns, in which case there's no need for the matches.



The flare might be useful if a tank valve gets frozen and you need to heat it up or something.

I think it's more likely to be useful as a flare. You get within radio range of the mothership, you ask if they can see you, you fire the flare and ask if they can see it.

Or, when you run out of air, you fire the flare as a desperation ploy.


The radio might be useful for contacting someone in orbit, who could relay info to the receiving party or coordinate them meeting you half way.



The problem with this scenario is that it's so hard to make it make sense. You have a crew. Fine. No mention of how big it is. You have a life boat. Which means that your descent vehicle is also your ascent vehicle and reentry vehicle. It's a good idea to leave your wreck and march to the mother ship. Why? You are meeting a mother ship. Why? You banged up your vehicle on landing, ruining most of your lunar excursion gear but leaving the crew (well, some of it, at least) alive (maybe a landing leg collapsed). You have no radio capable of reaching the earth (if there was a radio, you'd let the bright boys at NASA give you their recommendations). There is no lunar settlement (or else you wouldn't have to make the trek). The mothership is going to stay at least two weeks. The mothership apparently has enough fuel to take any surviving crew members from your wreck back to earth.

The situation could be made to make sense, i suppose. The mothership isn't really a mothership, but a lunar base (presently unoccupied). Your flight was the first manned visit to the base. Most of the supplies are in the base, your flight was just personel and a return craft. Earth won't be able to send a resupply mission for at least three months. Whatever.

You still need to know something about the capabilities of your suits. Do they crack CO2 and H20 back into O2? Do they collect H2O or dump it? How far and how fast can you march in one? And then you need to know where the base is. You're 200 miles from it. It's currently daytime--will it still be daytime by the time you get there, or are you going to have to worry about marching the last bit with just the earth for light?

Quasi
2002-Nov-19, 01:11 AM
On 2002-11-18 17:06, JS Princeton wrote:
Quasi, you are obviously smarter than your teacher and proving that you are to him or her will probably only make things worth.


My intention wasn't to make her mad or prove superiority or anything like that, I simply wanted to make sure that the rest of the class didn't walk away with bad information in their head. Making the person in charge of your GPA mad is generally a bad, bad thing /phpBB/images/smiles/icon_smile.gif



I think you got a little too hot under tha collar about the heating element. Indeed, radiative heat can be transfered through a vacuum. I don't know what kind of heating element is built, but it could very well provide warmth if its primary energy generation went into creating appropriate wavelength photons.


Yes, it can provide some degree of warmth but very little unless you are actually in direct contact with the heated area, and also since heat would not be very likely to transfer very well through a suit designed to protect you from extreme elements.

Colt
2002-Nov-19, 01:15 AM
Good ideas guys.

Here are the specs for a .45-ACP FMJ.

Cartridge and size .45 ACP - 11.43mm weight, gramms 12.025 Type FMJ muzzle velocity, m/s 235 muzzle energy, J 326

---------------------------------------------

Maybe the reason you have to reach the Lunar base is that it has just emerged from the darkside. The solar cells, that power the station, need to charge for at least two weeks, and needs a human there to deploy and orient them. You have two weeks to reach the station and deploy the solar cells, this would be the amount of time before the station (on the equator) reaches it's zenith.

When you fired your descent engine it malfunctioned and would not shut down until it's fuel was expended. This put your lander into a high, ballistic trajectory. You were able to slow the descent using your RCS thrusters, in the crash most of your supplies were destroyed and your fellow crewmate was killed.

This might include a deployable rover that only has one undamaged fuel cell, maybe enough to get halfway there but you have to leave behind half of the items.

Anyway, I have other things to do and for some reason this has taken me about 40 minutes to type.. -Colt

_________________
"I'm afraid. I'm afraid, Dave. Dave, my mind is going. I can feel it. I can feel it. My mind is going. There is no question about it. I can feel it. I can feel it. I can feel it. I'm a...fraid." http://www.geocities.com/wandererofthewastes/index.html

<font size=-1>[ This Message was edited by: Colt on 2002-11-18 20:19 ]</font>

JS Princeton
2002-Nov-19, 12:22 PM
On 2002-11-18 20:11, Quasi wrote:

Yes, it can provide some degree of warmth but very little unless you are actually in direct contact with the heated area, and also since heat would not be very likely to transfer very well through a suit designed to protect you from extreme elements.



No direct contact is needed for radiative heat transfer. Physical contact is only needed for conduction and (arguably) convection. The insulated nature of suits is a good point, but to the degree that they are NOT insulated, that's the degree you'd want a heat source. Sort of a catch-22 situation, if you see what I mean.

This whole endeavor is basically a glurge anyway, so I wouldn't read to deeply into it.

Irishman
2002-Nov-19, 01:54 PM
Okay, why do you need shelter from the sun? You're in a space suit that is designed to handle the temps, no? And why do you need a heater and shelter from the sun? Sun = heat, no sun = no heat. Hmmm.

Unless you're in darkness. Then you might need the heater, but how do you use it and walk?

Of course they probably expect you to assume items are compatible with your space suit - the air bottles, the food and water. Maybe even the heating unit - it plugs into your suit, that's how it works. That still leaves the matches as useless.

Regarding the guns, the astronauts and their suits could mass 300 lbs. That's mass, not weight. (I know that's screwy units. Call it "mass the equivalent to have 300 lbs weight on Earth".) And if they're carrying all their gear, that would be a whole lot more.

Hey, you folks thinking the pistols could be used for propulsion, what about those air tanks and your heating unit you're trying to carry? Did you factor that into your propulsion equation? Say you're dragging it all in your life raft. That makes a pretty good anchor.

I imagine that with the lunar dust, the raft would hold up okay for a while.

daver
2002-Nov-19, 08:36 PM
On 2002-11-19 08:54, Irishman wrote:
Okay, why do you need shelter from the sun? You're in a space suit that is designed to handle the temps, no?

You're going to be sleeping for maybe 1/3 of your trip. Maybe your suit uses evaporation of water (well, sublimation of ice) to cool itself (i believe the Apollo suits did); you're short on water anyway so you rig a tent when you're sleeping and a parasol when you're trekking. Most heat is transferred through conduction; you might want to rig the parachute as a hammock even in daylight to avoid touching the ground with the less insulated parts of your suit.



And why do you need a heater and shelter from the sun? Sun = heat, no sun = no heat. Hmmm.

Well, it's daylight now, but will it be daylight by the time you get there? If you were on the farside and the sun went down before you got to the base you'd be dead, dead, dead, but most likely you're nearside, so earthlight may be sufficient to light the way.


Unless you're in darkness. Then you might need the heater, but how do you use it and walk?

You use it when you're resting and not producing as much heat.


That still leaves the matches as useless.

Yep.


I imagine that with the lunar dust, the raft would hold up okay for a while.

Not really. Lunar dust is extremely abrasive. If you're actually dragging it, i don't suppose it would last a mile. It might be feasible to use it as a ground cover while sleeping, but i don't expect it would last more than a couple of sleep periods.

aporetic_r
2002-Nov-20, 01:34 AM
I imagine that with the lunar dust, the raft would hold up okay for a while.


Not that it really matters, considering how inane the whole test is, but the raft does not need to be inflated and/or dragged. The un-inflated (nonflated?) raft can simply be wrapped up around the stuff and carried by one or more strandees.

Colt
2002-Nov-20, 06:49 AM
^ Taking into account that this test is a ripoff of a "You have been shipwrecked on a desert isle.. blah..", that stuff is probably Terran weights for it, so just devide it all by six and there you go ./phpBB/images/smiles/icon_smile.gif -Colt

bArt2
2003-Jan-23, 07:28 PM
I don't like to bring back old topics, but it so happens that I had to do this test today, guess which team had (by far) the best results http://www.handykult.de/plaudersmilies.de/happy/bigok.gif

P.S. We had to give back the test by the way, because they want to keep it from being spread because then it looses it's value

<font size=-1>[ This Message was edited by: bArt2 on 2003-01-23 14:31 ]</font>

daver
2003-Jan-23, 11:16 PM
On 2003-01-23 14:28, bArt2 wrote:
I don't like to bring back old topics, but it so happens that I had to do this test today, guess which team had (by far) the best results http://www.handykult.de/plaudersmilies.de/happy/bigok.gif

P.S. We had to give back the test by the way, because they want to keep it from being spread because then it looses it's value

<font size=-1>[ This Message was edited by: bArt2 on 2003-01-23 14:31 ]</font>


Was this the homicidal version, where you had just enough air for two crew members to complete the journey?

Lexx_Luthor
2003-Jan-24, 04:53 AM
/phpBB/images/smiles/icon_biggrin.gif One thing not mentioned was a whistle. Never backpack without a whistle. tsk tsk

Lots of sunscreen.

A pistol could be useful if you fail to get saved.

If you travel to the moon, you better know your constellations. You don't need a sky map.


/phpBB/images/smiles/icon_lol.gif http://www.sanffo.co.uk/~holo/lexx/vidcaps3/390l.jpg

ToSeek
2003-Jan-24, 05:24 PM
On 2003-01-23 23:53, Lexx_Luthor wrote:

If you travel to the moon, you better know your constellations. You don't need a sky map.



I was thinking that, since it's not as if they change that much. Actually, the position of the Earth is a better clue: if it's directly overhead, you're at the "front" of the Moon. If it's not directly overhead, face toward it, and you're facing toward the "front" of the Moon, with the angle of the Earth above the horizon an indication of just how close you are to the "front."

Colt
2003-Jan-25, 06:04 AM
On 2003-01-23 14:28, bArt2 wrote:
[snip]

P.S. We had to give back the test by the way, because they want to keep it from being spread because then it looses it's value

<font size=-1>[ This Message was edited by: bArt2 on 2003-01-23 14:31 ]</font>


ROFL. /phpBB/images/smiles/icon_biggrin.gif -Colt

Rue
2003-Jan-25, 11:58 PM
In a book called Mars Crossing by Geoffrey Landis. A group of astronauts find themselves in a similar situation, but fortunetly NASA outfitted them with more useful stuff...such as vehicles!

jokergirl
2003-Jan-26, 01:26 AM
If you have to walk, it's going to take on the order of 10 days (20 miles/day seems fairly reasonable given the cumbersome lunar suit, maybe you could go faster. If this situation ever occurred the captain would have a better idea). Anyway, one person uses perhaps 10 lbs of O2 a day. So you have enough air for two people to survive the journey. So the first thing you do is grab the pistols and shoot everyone except someone who can also do arithmetic. Then maybe you and your crony can cart out all the useful items (and maybe use the box of matches to set a fire to blow up the wreckage).

You still can't use the box of matches, unless you want to spend the air you just acquired on the fire...
Shoot people in spacesuits? Wouldn't the air get lost?

A short addition on the life raft... We did this puzzle ourselves, and maybe you *could* use it for something, e.g. ride down a very steep incline, but I suppose it would be an *inflatable* liferaft too to fit on the moon lander? How would you inflate it? And if it had a tank of compressed air to do the trick, wouldn't you rather use it for yourself?

_________________
There are two things that are infinite: The Universe and Stupidity, although I'm not so sure about the Universe. -A. Einstein

Trying to weigh up plot device and BA... (http://auroracity.keenspace.com)

<font size=-1>[ This Message was edited by: jokergirl on 2003-01-25 20:27 ]</font>

joema
2003-Jan-26, 10:23 AM
I also took this exact same test about 30 yrs ago in Jr. high school.

Ironically a very similar scenario was vividly depicted in the Robert A. Heinlein novel "Have Space Suit -- Will Travel". Having to choose between carrying extra oxygen vs other items, how to mate the tanks to your space suit in a vacuum, predicting your speed across the lunar surface, water, heat, navigation difficulties -- it's all there.

It was a favorite book of mine, so I was excited in school when we got the test. Like many here I was technically oriented and had lots of deep thoughts about prioritizing the items.

Alas, it was a management exercise to observe group dynamics and decision making. In my case the teachers didn't even care what the "right" answer was, nor the technical validity of our reasoning. They just wanted to observe the group decision making process.

I vaguely recollect they finally announced the "right" sequence, which was totally wrong, technically. I remember thinking some non-technical management consultant probably devised this test after reading a newspaper article on Apollo.

Here are a few misc. thoughts on the list:

If you assume the 200 mi. will be on foot, that's a long way, even at 1/6th g. It's a 20+ hr trip, assuming an Apollo-era space suit at 1/6th g. By contrast the Apollo LRV "lunar rover" had a max range of 40 mi. Typical PLSS life support duration is about 8 hr, not long enough without supplemental oxygen. In reality suit coolant and CO2 scrubbing would also be limitations, not just O2. However the extra O2 is probably important, assuming it could be connected to the suit. A spare O2 tank without proper fittings and pressure equalization would be problematic (Heinlein described this well).

Water would be important, if you could get it into the suit. If you can't -- useless. Apollo-era suits had drinkable liquids tanks in the helmet, just as Heinlein predicted a decade prior. Maybe top it off before starting out?

Re the FM transceiver, this sounds very useful. However it's typically line of sight, so you'd need to be quite close for it to reach the mother ship. Lunar horizon is also much closer than on earth, further limiting the range.

Signal flares (if designed for a Lunar environment) might be more useful than the radio. However this would depend on flare height, brightness, number of flares, etc. The daylight lunar surface is very, very bright. If you assume people are looking for you, some kind of lunar surface dye marker might be more useful.

The stellar map sounds useful for navigation. However the lunar sun elevation is constant for long periods. You could maintain the same approximate travel direction by sun orientation as easily as by stellar orientation. Now if it was a lunar *surface* map, that would be useful. The test makers probably weren't smart enough to include that.

Likewise the magnetic compass wouldn't be useful for two reasons: sun angle would provide sufficient directional guidance, plus the moon doesn't have a magnetic field!! Compass wouldn't work, period!! Now if they offered a portable strap-down inertial reference unit (the LRV had one), coupled with a lunar surface map -- that would be useful.

The nylon rope might be useful for strapping on the extra O2 tanks, or climbing a lunar obstacle. Not needed if you're on a level plain.

Just some misc. thoughts. That test made an impression on me, but it wasn't the impression my teachers wanted to make!

-- Joe


<font size=-1>[ This Message was edited by: joema on 2003-01-26 05:30 ]</font>

cable
2003-Jan-26, 02:20 PM
_11__Portable heating unit what will it heat? no air to conduct it to your body

Are u sure ??
infrared rays may reach your skin even with no air ......

joema
2003-Jan-26, 10:44 PM
Here's a link to a web site with more info on the test, inc'l a supposed NASA answer: http://www.engin.umich.edu/dept/aero/msgc/lessons/alphabetical/moon.html Note they made some obvious mistakes such as using the pistols for self-propulsion, already proved here unworkable due to basic physics. However overall (considering there's no *one* right answer) their choices are plausible.

A few more thoughts:

.45 cal pistols -- guns work just fine in a vacuum. Gun powder contains both fuel and oxidizer. This question is frequently asked on sci.space.tech. See http://tinyurl.com/4xen for details.

Portable heating units -- In spacesuits, the problem on the moon is getting rid of heat, not getting cold. If the Apollo spacesuit water cooling mechanism failed on the moon, this was a serious problem due to heat build up.

First aid kit with hypodermic -- the above web site says the suits contain a special aperture for injection. If so it would definitely useful. Typically such kits contain dexedrine, morpheine, etc. Similar kits are used on Mt. Everest expeditions. On a multi-day journey across the moon, there are plausible scenarios where these could help boost energy or reduce suffering.

Food concentrate -- some spacesuits had a small pressure-tight aperture in the face plate where you'd insert a feeding tube and squeeze in food concentrate from a toothpaste-like tube. If available, on a 20+ hr journey, nourishment would help your strength.

Dehydrated milk -- if above food aperture not available, could be mixed with water and put in the helmet water tank. This would provide some food value. Apollo astronauts on long 8-hr lunar EVAs mixed orange juice concentrate with water and put in their helmet water tank. About 1 qt capacity if I recall.

In a real scenario using real Apollo space suits, the most criticle items would probably be oxygen, lithium hydroxide for CO2 scrubbing (the Movie Apollo 13 depicted this), suit cooling water, and battery power for the suit (batteries only last one 8-hr EVA). Remember a space suit is not like an open-loop SCUBA tank. It's an electronic, closed-loop rebreather system, so CO2 scrubbing and battery power is critical. Here's more info: http://quest.arc.nasa.gov/space/teachers/suited/5emu4.html

Some items are obviously of no use in most cases: matches, life raft.

If anyone is further interested in a realistic fictional depiction of this scenario, I highly recommend Robert Heinlein's 1958 book "Have Space Suit, Will Travel": http://tinyurl.com/4xf3

-- Joe

daver
2003-Jan-28, 07:16 PM
On 2003-01-25 20:26, jokergirl wrote:


If you have to walk, it's going to take on the order of 10 days (20 miles/day seems fairly reasonable given the cumbersome lunar suit, maybe you could go faster. If this situation ever occurred the captain would have a better idea). Anyway, one person uses perhaps 10 lbs of O2 a day. So you have enough air for two people to survive the journey. So the first thing you do is grab the pistols and shoot everyone except someone who can also do arithmetic. Then maybe you and your crony can cart out all the useful items (and maybe use the box of matches to set a fire to blow up the wreckage).

You still can't use the box of matches, unless you want to spend the air you just acquired on the fire...
Shoot people in spacesuits? Wouldn't the air get lost?



Well, you're all seasoned adventurers, you can all do the math, you all know that only two of you might be able to make the journey while the rest of the crew stay behind and play gin rummy until the air starts getting thick and one of them opens the air lock. The pistol is just to make sure that everybody sees reason.

If there are enough people who refuse to see the logic of the situation, you might be able to use the matches to cover up the evidence (air inside the spacecraft isn't going to do the people making the trek any good).




A short addition on the life raft... We did this puzzle ourselves, and maybe you *could* use it for something, e.g. ride down a very steep incline, but I suppose it would be an *inflatable* liferaft too to fit on the moon lander? How would you inflate it? And if it had a tank of compressed air to do the trick, wouldn't you rather use it for yourself?



The inflator might not use air (some solid fuel substance that relatively slowly and coolly). It might be possible to use the inflator for something (propulsion, signal flare). The raft probably wouldn't stay inflated long if used in a lunar environment (lunar soil is extremely abrasive).




_________________
There are two things that are infinite: The Universe and Stupidity, although I'm not so sure about the Universe. -A. Einstein

Trying to weigh up plot device and BA... (http://auroracity.keenspace.com)

<font size=-1>[ This Message was edited by: jokergirl on 2003-01-25 20:27 ]</font>

daver
2003-Jan-28, 07:26 PM
On 2003-01-26 05:23, joema wrote:
I also took this exact same test about 30 yrs ago in Jr. high school.
...

If you assume the 200 mi. will be on foot, that's a long way, even at 1/6th g. It's a 20+ hr trip, assuming an Apollo-era space suit at 1/6th g. By contrast the Apollo LRV "lunar rover" had a max range of 40 mi.


I think that is seriously underestimating the amount of time it would take. 20 miles is reasonable day's travel on earth. 10 mph sustained on the moon doesn't seem at all reasonable. However, presumably that's one of the things that the crew in question would know that we don't. One of the many reasons its an annoying test.




Typical PLSS life support duration is about 8 hr, not long enough without supplemental oxygen. In reality suit coolant and CO2 scrubbing would also be limitations, not just O2. However the extra O2 is probably important, assuming it could be connected to the suit. A spare O2 tank without proper fittings and pressure equalization would be problematic (Heinlein described this well).



Heinlein's space suits were an open system--the exhausted air was used as a coolant. Most of the air they carried was in the form of O2; once (i've forgotten the names) Junebug gave PeeWee an air cylinder instead of an O2 cylinder as a bit of relief.

Something that wasn't on the list that in any conceivable situation would be is duct tape. As i remember, that was pretty useful in the Heinlein story.




Water would be important, if you could get it into the suit. If you can't -- useless. Apollo-era suits had drinkable liquids tanks in the helmet, just as Heinlein predicted a decade prior. Maybe top it off before starting out?

Re the FM transceiver, this sounds very useful. However it's typically line of sight, so you'd need to be quite close for it to reach the mother ship. Lunar horizon is also much closer than on earth, further limiting the range.

Signal flares (if designed for a Lunar environment) might be more useful than the radio. However this would depend on flare height, brightness, number of flares, etc. The daylight lunar surface is very, very bright. If you assume people are looking for you, some kind of lunar surface dye marker might be more useful.

The stellar map sounds useful for navigation. However the lunar sun elevation is constant for long periods. You could maintain the same approximate travel direction by sun orientation as easily as by stellar orientation. Now if it was a lunar *surface* map, that would be useful. The test makers probably weren't smart enough to include that.

Likewise the magnetic compass wouldn't be useful for two reasons: sun angle would provide sufficient directional guidance, plus the moon doesn't have a magnetic field!! Compass wouldn't work, period!! Now if they offered a portable strap-down inertial reference unit (the LRV had one), coupled with a lunar surface map -- that would be useful.

The nylon rope might be useful for strapping on the extra O2 tanks, or climbing a lunar obstacle. Not needed if you're on a level plain.

Just some misc. thoughts. That test made an impression on me, but it wasn't the impression my teachers wanted to make!

-- Joe


<font size=-1>[ This Message was edited by: joema on 2003-01-26 05:30 ]</font>

tracer
2003-Jan-28, 11:28 PM
On 2002-11-13 20:50, Quasi wrote:
Another thing, any truth this being an actual NASA test? A couple things about it make me think not.......
You mean like the fact that it says you're part of a "spcae crew"? /phpBB/images/smiles/icon_wink.gif

<font size=-1>[ This Message was edited by: tracer on 2003-01-28 18:29 ]</font>

MadChemist
2003-Jan-30, 07:06 AM
heh... somewhat unrelated but has anyone taken an even more diabolical "test?" I can't remember much about it, just that it involves a lot of people on a liferaft that can only float with one less than the total number in the group. We were supposed to assign values to the different people based on occupation and/or station in life (such as doctor, pregnant woman, etc.) ... Sometimes I wonder what kinda of sadistic freaks sit around to think up these tests!

David Hall
2003-Jan-30, 02:23 PM
On 2003-01-30 02:06, MadChemist wrote:

heh... somewhat unrelated but has anyone taken an even more diabolical "test?" I can't remember much about it, just that it involves a lot of people on a liferaft that can only float with one less than the total number in the group.

No, but I did once take one of the more common "liferaft" tests, where we had to rank the items according to their usefulness in such a situation.

It was really funny because I had just finished reading Adrift (http://www.amazon.com/exec/obidos/ASIN/1885283164/002-3668669-6823238), a true story about a man lost at sea for 76 days. I got a little angry because some of the things on the "official" list didn't seem to be all that useful to me, and vice-versa. I particularly remember one, I think it was some plastic sheeting, that they ranked rather low, but which I could think of several uses for, like catching rain water with.

The big problem with tests like these are the built in assumptions that the authors just assume the takers will take into consideration. Especially this Moon one has a ton of unwritten assumptions that affect the decision-making. Just look back at all the posts here. Nearly all of them have some variation of "if...then...". That alone makes it a poorly-designed exercise.

I agree with joema. These things are designed by people who don't care much what the final result is, just how it was made. This just seems wrong to me. I also think the teachers are wrong for marking "wrong" answers that have sound basis behind them. Refusing answers just because the sheet says so actually promotes poor decision-making. If someone in the group has technical knowledge that affects the final outcome, then good decision making depends on recognizing it. What good does it do to make decisions by committee if the decisions end up making your party dead?

I suppose these tests are good for one thing though. They provide a realistic simulation of actual business meetings. Perhaps that's what they are really teaching? /phpBB/images/smiles/icon_biggrin.gif

MadChemist
2003-Jan-30, 03:10 PM
On 2003-01-30 09:23, David Hall wrote:
I suppose these tests are good for one thing though. They provide a realistic simulation of actual business meetings. Perhaps that's what they are really teaching? /phpBB/images/smiles/icon_biggrin.gif



By Jove, I think he's got it! That really does make a lot of sense... who cares if you live or die if you can exhibit good teamwork /phpBB/images/smiles/icon_biggrin.gif

joema
2003-Jan-30, 03:31 PM
Heinlein's space suits were an open system--the exhausted air was used as a coolant.

He wasn't consistent on this. He referred to a CO2 scrubber and several times to an ear lobe pulse oximeter for monitoring blood oxygen levels. There are typical of a closed loop system. Also the EVA durations were far beyond what a two-tank open loop system can support.

However he also referred to adiabatic cooling and exhausted air, plus mentioned the different cooling characteristics of pure O2 vs oxy-helium. These are typical of an open system.

Heinlein's description wasn't perfect, but for a supposedly "juvenile" fiction book written in 1958, he did pretty well.

GrapesOfWrath
2003-Jan-30, 03:51 PM
On 2003-01-30 02:06, MadChemist wrote:
heh... somewhat unrelated but has anyone taken an even more diabolical "test?" I can't remember much about it, just that it involves a lot of people on a liferaft that can only float with one less than the total number in the group. We were supposed to assign values to the different people based on occupation and/or station in life (such as doctor, pregnant woman, etc.) ... Sometimes I wonder what kinda of sadistic freaks sit around to think up these tests!

And, there's a reason that a corporate team training consultant is never listed in the occupations on the raft--it would make the test too easy.

daver
2003-Jan-30, 06:42 PM
On 2003-01-30 10:31, joema wrote:


Heinlein's space suits were an open system--the exhausted air was used as a coolant.

He wasn't consistent on this. He referred to a CO2 scrubber and several times to an ear lobe pulse oximeter for monitoring blood oxygen levels. There are typical of a closed loop system. Also the EVA durations were far beyond what a two-tank open loop system can support.



It's been a while; i don't remember the CO2 scrubber. I do remember the ear lobe O2 monitor. That should be trivial to do with current technology. Every now and again i read about some people dieing after wandering into a room filled with N2. Unfortunately, i don't think the monitor would help in this case--you might hear the monitor going off before you pass out.

You're right about the EVA durations. I remember SCUBA dives, and how long a bottle of air lasted. I suppose the system could be semi-closed--scrubbers and air exhaust for cooling.

As i said, i don't remember the scrubbers, or if they needed to be replaced. Maybe there was some sort of centrifugal concentrator (built into the pumps) that would exhaust CO2 enriched air.




However he also referred to adiabatic cooling and exhausted air, plus mentioned the different cooling characteristics of pure O2 vs oxy-helium. These are typical of an open system.

Heinlein's description wasn't perfect, but for a supposedly "juvenile" fiction book written in 1958, he did pretty well.




Yep. When were the first self-contained space suits? Probably Gemini--at least the suit i found a picture of had provisions for a backpack. OK, i found a web site. It says that Gemini used a gas cooling and ventilation system, that it was not very effective. Apollo was the first liquid cooled suit.

joema
2003-Jan-31, 09:12 AM
Regarding the test, a key element in formulating your prioritization strategy is your estimate of travel speed across the lunar surface for 200 miles. You'd need different items for a 20 hr journey than for a 100 hr journey. Previously I estimated 20+ hrs, because I figured 10 mph was the absolute fastest possible speed, with slower sustained speeds more likely.

I wonder if it's possible to figure this out using currently available information? It seems at 1/6th g, you could go pretty fast. Most of the Apollo footage isn't of much help, for several reasons: they weren't *trying* to go fast -- just be safe. They didn't have far to go on foot. Early missions had stiffer, less mobile suits so they couldn't go that fast. Later missions had more flexible suits, but those also had the LRV, so long distence, higher speed travel on foot wasn't needed.

In actual "real" life, with a real Apollo suit, the 200 mi. trip just wouldn't be possible with the items from the NASA test. It's just too far, and a real suit would run out of battery power, cooling water, and LiOH CO2 scrubbers. All these need replenishing at about 8hr intervals. Under heavy exertion, the cooling water (which the sublimator gradually releases to the vacuum for cooling) doesn't even last 8 hr.

However momentarily disregarding these, how fast could you go, both short term, and sustained over long periods? On earth a marathon runner averages about 11 mph for 2.5 hrs. The Apollo 11 suit inc'l PLSS weighed about 180 lbs on earth. A Shuttle EVA suit weighs about 150 lbs. Split the difference and divide by 6, and you're carring about 28 lbs on the moon. Combined with your body weight that's about 60 lbs total.

Considering all this, how fast could you go on the moon in a life-or-death situation? The key point is over what distence. I think you could break 20 or 30 mph for a few min. It's 1/6th g, there's no wind resistence, your liquid cooling garment controls heat build up, and you're going to die if you don't go fast -- falling down is less a concern than normal. For a 200 mi trip, I'd say about 7 mph, not including time to sleep, if needed. But that's just a wild guess. It would also depend on how much extra equipment you're carrying. If each person carried an extra 100 lb (16 moon pounds) O2 cylinder, that would slow you down further.

Re oxygen capacity, the Apollo 15-17 suits had two bottles at 1430 psi, holding 1.5 lbs O2 mass each, with an endurance of about 8 hr. So each person would consume 2 (bottles) x 1.5 (lbs/bottle) x 3 (8 hr periods) per day or 9 lbs oxygen mass per day. This means each "100 lb" extra O2 bottle in the test would last roughly 8 days, assuming 80% of the 100 lb weight was compressed O2 (which is impossible for gaseous O2. Maybe it's LOX?) That places an outside limit on the trip duration for this theoretical exercise, regardless of speed.

-- Joe

daver
2003-Jan-31, 07:34 PM
On 2003-01-31 04:12, joema wrote:
Regarding the test, a key element in formulating your prioritization strategy is your estimate of travel speed across the lunar surface for 200 miles. You'd need different items for a 20 hr journey than for a 100 hr journey. Previously I estimated 20+ hrs, because I figured 10 mph was the absolute fastest possible speed, with slower sustained speeds more likely.

I wonder if it's possible to figure this out using currently available information? It seems at 1/6th g, you could go pretty fast. Most of the Apollo footage isn't of much help, for several reasons: they weren't *trying* to go fast -- just be safe. They didn't have far to go on foot. Early missions had stiffer, less mobile suits so they couldn't go that fast. Later missions had more flexible suits, but those also had the LRV, so long distence, higher speed travel on foot wasn't needed.

In actual "real" life, with a real Apollo suit, the 200 mi. trip just wouldn't be possible with the items from the NASA test. It's just too far, and a real suit would run out of battery power, cooling water, and LiOH CO2 scrubbers. All these need replenishing at about 8hr intervals. Under heavy exertion, the cooling water (which the sublimator gradually releases to the vacuum for cooling) doesn't even last 8 hr.

However momentarily disregarding these, how fast could you go, both short term, and sustained over long periods? On earth a marathon runner averages about 11 mph for 2.5 hrs. The Apollo 11 suit inc'l PLSS weighed about 180 lbs on earth. A Shuttle EVA suit weighs about 150 lbs. Split the difference and divide by 6, and you're carring about 28 lbs on the moon. Combined with your body weight that's about 60 lbs total.

Considering all this, how fast could you go on the moon in a life-or-death situation? The key point is over what distence. I think you could break 20 or 30 mph for a few min. It's 1/6th g, there's no wind resistence, your liquid cooling garment controls heat build up, and you're going to die if you don't go fast -- falling down is less a concern than normal. For a 200 mi trip, I'd say about 7 mph, not including time to sleep, if needed. But that's just a wild guess. It would also depend on how much extra equipment you're carrying. If each person carried an extra 100 lb (16 moon pounds) O2 cylinder, that would slow you down further.

Re oxygen capacity, the Apollo 15-17 suits had two bottles at 1430 psi, holding 1.5 lbs O2 mass each, with an endurance of about 8 hr. So each person would consume 2 (bottles) x 1.5 (lbs/bottle) x 3 (8 hr periods) per day or 9 lbs oxygen mass per day. This means each "100 lb" extra O2 bottle in the test would last roughly 8 days, assuming 80% of the 100 lb weight was compressed O2 (which is impossible for gaseous O2. Maybe it's LOX?) That places an outside limit on the trip duration for this theoretical exercise, regardless of speed.

-- Joe


The lunar rover was said to enormously increase the range over which the astronauts could explore. Which has some bad implications for lunar marathons.

I'm eyeballing from memory here, but it looks as if the lunar skip was about the equivalent of a fast walk. Just guessing, maybe a 12-minute mile. Which makes a 40 hour trip. If you don't have some decent keep-awake drugs, you're going to have to take at least one sleep break (the lunar surface is not a good place to start hallucinating). So close enough to 48 hours. I'm assuming the terrain is mostly navigable--you don't have to waste time exploring and backtracking. It'd sure be nice to have an extra day for contingency purposes.

The rule of thumb that i heard was about one cubic meter of air per hour. So 24 kg of air per day, or about 10 pounds of O2 per day. That's while resting. Moderate activity would probably double that. I found an exercise site that says that well-conditioned athletes can consume better than 6 liters O2/minute. That works out to be about 20 pounds/day. Our crew wouldn't be able to sustain that level of exertion, but we're probably talking 15 pounds/day. We're looking for light, athletic crew members to make the trek, preferably women.

One tank might allow two crew members to make the journey. Once there they could load up a rover with air and water and head back to the crash site to bury the corpses or rescue the survivors.

So. If you have four or fewer crew members, all healthy, everyone can make the trip. Round trip might take three days if you're lucky (two to get there, one to drive back). Maybe that's enough air for four or five crew members to stay behind with the other oxygen bottle. If the ship has more O2 available that wasn't in the carry list (maybe some oxidizer left in the descent engine) you can leave more people behind. Otherwise you draw straws (here's where you can use those matches).

dgavin
2003-Feb-02, 04:25 AM
Here is what I would take.
The Tanks of O2, the parachute, the pistol, and the radio.

I would attach the paracute cords to one tank of O2, then lean the O2 tank against some wreckage so it's roughly aimed at a 35 degree angle above the horizion towrds the direction of the mother ship. Placing the other tank and myself in the canopy of the chute, I'd then use the pistol to shoot off the value. Viola! One make shift torpeo, that in moons gravity might actually have some pull power as everything weighs 1/6 less. After landing, if survive that, would repeat this with the second tank of O2, during that flight I'd use the radio to call the mother ship and yell...

"INCOMING!!!!!!!"

SeanF
2003-Feb-03, 02:48 PM
On 2003-02-01 23:25, dgavin wrote:

...lean the O2 tank against some wreckage so it's roughly aimed at a 35 degree angle above the horizion...



Wouldn't a 45-degree angle be more efficient? /phpBB/images/smiles/icon_smile.gif

nebularain
2003-Mar-04, 11:48 PM
Interesting. I was looking through a list of curriculum designs for high school space science classes on the web, and I found this test!! There was a link to the answers:
http://www.nat.k12.la.us/wf/crash2.jpg

I found some of the answers to be interesting, such as the parachute being used as a sun shield. Of course, the answers didn't take into account how people could eat and drink through their space suits.



_________________
The lesser lights to rule the night, glimmers of glory, distant suns

<font size=-1>[ This Message was edited by: nebularain on 2003-03-05 00:52 ]</font>

Charlie in Dayton
2003-Mar-05, 03:43 AM
On 2003-02-03 09:48, SeanF wrote:


On 2003-02-01 23:25, dgavin wrote:

...lean the O2 tank against some wreckage so it's roughly aimed at a 35 degree angle above the horizion...





Wouldn't a 45-degree angle be more efficient? /phpBB/images/smiles/icon_smile.gif



Nope...at least for a bullet or artillery shell, so I'm guessing that in this instance that's what's being thought of...

I do wish I could remember where I got this info, but as I recall, the most efficient (read longest shot) angle of launch for artillery etc is right around 40 degrees. Any higher elevation, and you lose so much velocity in the vertical that there's not enough to translate to the horizontal. Your objective is to get OVER there, not UP there.

I'm gonna have to go dig out those old physics textbooks and look up the sections on velocity and ballistics again...

Of course, a rocket (such as the tank in question comes out to be) may be totally different. A steady shove is not the same as an explosive bang/long coast...
_________________
I am Dyslexia of Borg; prepare to have your *** laminated. - Lori Martin

Yours in cogno-intellectualism
Charlie in Dayton

<font size=-1>[ This Message was edited by: Charlie in Dayton on 2003-03-04 22:44 ]</font>

RichField
2003-Mar-05, 04:16 AM
45 degrees is the angle for the longest distance in a vacuum. The equations end up requiring the maximization of cos(q)sin(q) where q is the angle of fire. The angle that maximizes this is 45 degrees. The key here is that there is no horizontal acceleration.

For artilery and ballistics air resistance adds both horizontal and vertical acceleration which brings the optimal angle below 45 degrees.

Rich

Irishman
2003-Mar-05, 05:42 AM
bArt2 said:

P.S. We had to give back the test by the way, because they want to keep it from being spread because then it looses it's value

Part of the purpose is the problem solving skills. This purpose is defeated when the people have seen the problem before, and already thought about the answer. If you share the test with others in later classes, then they have a head start. Of course, participation here gave you a head start. So much for intentions. /phpBB/images/smiles/icon_wink.gif

dgavin, that plan doesn't seem very well thought out. Consider the discussions of the LM, and the effects of the thrust from the engines as it landed. The exhaust quickly disperses in a wide plume. Also, how much pressure is the oxygen under, and how far away from the parachute is the bottle? Finally, even if you got some lift out of this plan, the optimistic assessment of how far this would take you is a few hundred yards.