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JohnD
2004-Nov-09, 11:45 PM
I've just been watching the first episode of this new TV miniseries on BBCtv in the UK. Has it been shown on US? In case of different US title - vast 2001 style space craft explores Venus, Mars, Jupiter and next week, Saturn, Neptune and Pluto. It sets out to be a serious minded projection of what might be possible a few years from now.

If it has not been shown statside, contribuotrs there may not be able to comment, but if it has, is this bad science or not? Eg. Humans landing on Venus, to sample Venara probe.
John

mickal555
2004-Nov-10, 04:33 AM
Humans on venus NOT likely
I mean not even robots can survive for over 30mins.
after maby 100's of years who knows

kucharek
2004-Nov-10, 06:49 AM
As it was co-produced with a German tv channel, it will be aired already next week here. It's on Pro 7, 18. November, 20.15h. I'm looking forward to that.

Harald

eburacum45
2004-Nov-10, 07:12 AM
the ship uses fusion and liquid hydrogen fuel, together with some other features such as a magshield which seem very desirable.

http://www.siderealgames.com/uploads/mship.jpg

Apparently this ship has a 400-metre aerobraking shield at one end, which can be used to slow sown the ship on arrival at a planet with a respectable atmosphere- this technique was used at Jupiter to insert the ship into orbit. It also serves as a sun shield- the ship has solar panels as well while in the inner system.

A similar concept was used in Arthur Clarke's 2010; but the 'ballute' in that movie was somewhat poorly suited to the task by all accounts.
Perhaps this design will be better. Aerobraking can cut down on fuel requirements considerably.

In the centre of the shield is a fusion motor of some sort, the main method of propulsion; apparently the motor uses hydrogen, but I cant see where the tanks are supposed to be; perhaps they are in the aerobrake shield. Some possible heat issues there.

The main hab area is made of recycled Shuttle Tanks; This reminds me of Dave Dietzler's interplanetary nuclear rockets-
http://groups.msn.com/DaveDietzler/newnuclearthermalrockets.msnw

and there is a small rotating centrifuge area to alleviate the effects of zero gee exposure. The main habitats have a small magshield at each end to protect against solar radiation events. How effective that would be I'm not sure.

The Y shaped effort at the near end appears to be a Brayton cycler turbine power generator; also mentioned on Dave's site (highly recommended site by the way)

Van Rijn
2004-Nov-10, 07:36 AM
How did they handle the Venus landing? Did they describe the difficulties? It might just be possible to create something like an ocean hardsuit, heavily insulated. You would need a truly impressive "air conditioner" - probably a hose connection to a lander with a nuclear reactor and monster heat exchangers. It wouldn't be easy but not absolutely impossible.

Sounds interesting, though. Star Trek is fun, but it is time we remember that there are plenty of worlds in our own neck of the woods.

eburacum45
2004-Nov-10, 07:55 AM
How did they handle the Venus landing? Did they describe the difficulties? It might just be possible to create something like an ocean hardsuit, heavily insulated. You would need a truly impressive "air conditioner" - probably a hose connection to a lander with a nuclear reactor and monster heat exchangers. It wouldn't be easy but not absolutely impossible.

It was a hard suit alright; it could withstand Venus' environment for one hour supposedly.

The best thing was the heat distortion of the optics, making the surface of Venus look like a bowl;

on Mars, too, the low gravity was well depicted.

JohnD
2004-Nov-10, 08:44 AM
Ok, if it has been seen elswhere, we can discuss it.

On the Venus 'landing'. The only activity that the single human achieved was to set up some instruments, one of which imploded and to inspect the Venera probe, which they managed to land beside (!). Another stood by in the lander. I'm a romantic supporter of human exploraration, but are we really persuaded that the effort to put humans on Venus would be worth this?

The transit from Venus to mars was shown as by a gravity sling around the Sun, apparently penetrating the corona. Oh, come on! One to two MILLION degrees K.

Mars - I liked!

The Jupiter aerobraking. A 400metre disk, on the end of a 2 kilometre thin spike, with the CofG about two thirds of the way down. Reminds of those plate spinning acts, with a plate that isn't spinning, so no gyroscopic stability, and no way of adjusting the stick. Is this a serious engineering concept? If the plate and stick get even slightly out of line, the whole thing becomes unsteerable.

Lastly, and not science, the programme failed to bridge the gap between a scientific projection and a dramatic story. The characters are stereotypes and there is very little exposition. The only characterisation is that the human who walks on Venus is the son of the Russian Venera designer! Possible, even likely, but a desperate attempt at human interest. I don't want a 'love interest', but films like Apollo 13 and the Right Stuff vividly showed the drama of space exploration (IMHO), and the interaction between the protagonists.

John

kucharek
2004-Nov-10, 08:49 AM
The transit from Venus to mars was shown as by a gravity sling around the Sun, apparently penetrating the corona. Oh, come on! One to two MILLION degrees K.
I doubt if the 2MK would be the real problem, as it is a very thin gas and so not very much heat energy is transported. I see a bigger problem in the sun itself with all its radiated heat.

And also to me a manned landing on Venus makes no sense, except for the "because it is there".

Harald

mickal555
2004-Nov-10, 08:50 AM
Ok, if it has been seen elswhere, we can discuss it.

On the Venus 'landing'. The only activity that the single human achieved was to set up some instruments, one of which imploded and to inspect the Venera probe, which they managed to land beside (!). Another stood by in the lander. I'm a romantic supporter of human exploraration, but are we really persuaded that the effort to put humans on Venus would be worth this?

The transit from Venus to mars was shown as by a gravity sling around the Sun, apparently penetrating the corona. Oh, come on! One to two MILLION degrees K.

But remember Temperature isn't a guarantee of heat, if there are hardly any particles the heat transfer won't be much. The same reason why you don't instantly freeze when in space (without suit).
Oh someone allready ansered :(

Glom
2004-Nov-10, 09:15 AM
It was okay. I found it a little bit boring because they were trying to cross a speculative documentary with a dramatisation and did neither superbly. There was little talk of the cool things about their mission, just a collection of shots of them milling about. It was produced well though. The effects were good, there were no stars in a lot of the shots and I liked the near miss thing in the asteroid belt.

Richard of Chelmsford
2004-Nov-10, 10:31 AM
http://bbc.co.uk/science

I thought it was brilliant. Of course it wasn't as good as the real pictures we've had from the moon way back when, and those we get from planetary probes, but it was very well done.

Plus the fact that all we got was the science, not all the girly stuff..you know, human relationships, marital problems back home, political implications and so on.

Someone said 'No way!' to Venus..true, but it was fascinating to see a fictional landing..right from the moment they broke through the cloud cover to see the red hot landscape spread out below. Yes, they landed close to Venera, but Apollo 12 landed close to another previous moon probe, didn't it? (forget its name)

The suits for Venus were made of titanium, by the way, and tested in a blast furnace. The astronaut made the comment that the atmosphere was very thick..like water..sounds like my house with the heating turned up too much!

Fascinating to see the lander blast off from Venus..it would have to be very powerful to get off an Earth sized planet, and this came across very well.

The shots on Mars reminded me rather of some of the Mars films..the one with Tim Robbins comes to mind. Something was made of the danger of solar falres..reminds me rather that if one of Proxima Centauri's stars went supernova, that's curtains for us, isn't it?? :evil:

The ship was called Pegasus..Arthur C. Clarke -ish.

And international crew? Two Yanks, Two Brits, one Russian cosmonaut. No taikonauts or French ESA or Indians.

But it was still great.

Book me on the first trip when they build the thing, I've still got 27 years to go before I make it as oldest astronaut status. :)

Oh yes, and as Glom says, don't miss the near miss in the asteroid belt..two giant rocks whooshing past like an express train.

Glom
2004-Nov-10, 10:34 AM
I thought the mission was weird. Going to six planets and a KBO all in one mission. A bit demanding. But it was still a good vehicle for giving a demonstration of how a manned exploration of those different bodies would be conducted.

Sleepy
2004-Nov-10, 11:34 AM
No lag in radio comms.

The whole lets land on Venus: Why? What possible science justifies risking 2 crew just so one guy can place a camera and seismograph and see the probe his grandfather made? Surely a seismograph which would only last a few hours at most is a pointless waste of time. Wouldn't you need a lot longer to collect meaningful data?

Venus lander: just what fuel does it use to escape from Venus.

Just how did they detect the asteroid with over 30 warning minutes when travelling at over 1Km/sec (my estimate)?

eburacum45
2004-Nov-10, 12:37 PM
There was lag in radio comms between the ship and ground control, but no lag between the ship and the various landers.

The asteroid; unexplained. Radar perhaps; but the 'number of data points' was mentioned, suggesting this asteroid had been observed from Earth.

The fuel in the Venus lander- unexplained; whatever it is, why don't we use it on Earth?

To pack such a punch. I would suspect some kind of nuclear rocket- hope the crew compartment is well protected (unless it is aneutronic fusion)

Amadeus
2004-Nov-10, 12:54 PM
Personaly I thought it as good. Remember this was not a hard core science problem but an attempt to get accross the ideas to lay-people.

It was made by the same team that did the series "walking with dinosours"

There was time lag between the mission and earth.

The mission to venus collected tock samples as well as placeing the doomed sensors so there was some merit in that. Plus it was on the way!

As for detecting the asteroid with 30 mins warning, well it was a bit big! I can asume it was some kind of radar.

There was a follow-up program on bbc4 that went into the science behind it a lot more and looked at the robotic missions to these planets.

Sleepy
2004-Nov-10, 02:13 PM
I dont think there was lag in the comms between Earth and Pegasus.

As they had over 30 minutes warning of the asteroid thats one hell of a radar to detect an object 1800 + miles away. Plus if they had radar then they would have had enough data to quickly work out whether they were going to collide.

As for collecting samples from Venus, well thats what robots are good for. And it wasn't on the way as you have to match orbits to land so it was a destination.

Mellow
2004-Nov-10, 02:40 PM
Well,

Agreed with most comments. I enjoyed the programme and you have to remember their target audience. I think it struck a pretty good balance betwen science and pseudo-drama. These days a pure science lecture in the old style of television science programmes would guarantee tiny viewing figures and hence, wouldn't get made in the first place.

Comments on the choice of mission, well it was done purely to make for one continuous story, rather than describing several planetary missions.

Venus..... well, everyone is in agreement that any instruments would not last for long, they even made reference to that in the programme. I just wonder if some of the recent advances in ceramic technology could produce casings for such instruments that would last for longer, anyone care to take up that one?

I think the programme makers should be applauded, I'm pleased to see anything that raises the general publics interest in space exploration.

:D

Richard of Chelmsford
2004-Nov-10, 04:18 PM
No lag in radio comms.

The whole lets land on Venus: Why? What possible science justifies risking 2 crew just so one guy can place a camera and seismograph and see the probe his grandfather made? Surely a seismograph which would only last a few hours at most is a pointless waste of time. Wouldn't you need a lot longer to collect meaningful data?

Venus lander: just what fuel does it use to escape from Venus.

Just how did they detect the asteroid with over 30 warning minutes when travelling at over 1Km/sec (my estimate)?

Of course this is the common sense view.

But it's a bit boring.

eburacum45
2004-Nov-10, 04:41 PM
I dont think there was lag in the comms between Earth and Pegasus.
They mentioned the comm lag once, but during the various landing episodes the cutting was rather rapid, so you couldn't tell when the laner was talking to Pegasus, or to Earth.


As they had over 30 minutes warning of the asteroid thats one hell of a radar to detect an object 1800 + miles away. Plus if they had radar then they would have had enough data to quickly work out whether they were going to collide.
That is the sort of radar that will be needed, though; if they insist on having a 400 metre shield, they will need to scan a 400 metre wide cylinder dead ahead for thousands of kilometers- if they spot a rock they would need enough warning to be able to move at least 200 metres sideways- say 200 seconds - at 1 km/s that is 200 km- but they will need more warning - say 1000 km.




As for collecting samples from Venus, well thats what robots are good for. And it wasn't on the way as you have to match orbits to land so it was a destination.
Absolutely; drop off a lander full of robots- no need to land at all.

Van Rijn
2004-Nov-10, 11:04 PM
Venus..... well, everyone is in agreement that any instruments would not last for long, they even made reference to that in the programme. I just wonder if some of the recent advances in ceramic technology could produce casings for such instruments that would last for longer, anyone care to take up that one?

I think the programme makers should be applauded, I'm pleased to see anything that raises the general publics interest in space exploration.

:D

I see no reason why hardware couldn't last long term on the Venus surface, though design would be tricky. For something that doesn't need to last long, you can just use good insulation and batteries (this is what Venera did). For something that needs to last awhile, you'd want an RTG or nuclear reactor, with a good heat exchange system. The reactor would need to operate at a higher temperature than ambient. There's some possibility for custom high temperature electronics, or you can put most of it in a thermos bottle, with a good air conditioner/heat pump (but what a heat gradient!).

Of course, having people walking on Venus is much harder.

I do have trouble with the near miss with the asteroid. Large asteroids would likely have been seen via telescope before the mission started. But it adds drama.

Agreed about programs like this. After a long dry spell, I think the idea of humans exploring the solar system is starting to be taken seriously again, not just as something we might do in the distant future. I hope we see this show in the U.S.

Sticks
2004-Nov-12, 08:49 AM
If only to see what Jay Utah makes of it :lol:

For those outside the UK, you will have to settle for this link (http://www.bbc.co.uk/sn/tvradio/programmes/spaceodyssey/)

Just one point, the visit Venus, then Mars, before the slingshot around the Sun. They make a passing reference to Mercury.

The problems I have seen with this so far are these:

1) A nuclear reactor in space
The only people I know who got away with this were the Russians. In the west, no government would allow nuclear material to go into space incase of an accident on launch. This would be politically unacceptable and there would be massive protests and lawsuits to stop this.

2) The landers
To get off of the gravity well we know of as the Earth, we need quite a lot bigger, expendable rockets than were depicted on the landers. The LEM's got away with it, because they were yanked by a larger wire - oops sorry :) it was only 1/6th g

3) Sun Fly by
Going through part of the Sun's atmosphere ???

Would anything withstand that intense heat and radiation? There is reference to a "magnetic" shield. How viable is that. Would not a magnetic field present it's own dangers (See the debate about Leukima clusters and high voltage power lines here on Earth)

4) the Asteroid Belt
Ignoring the near miss, what about the micro-meteroids, those too small to be detected, but big enough to punch holes through the craft. A micrometeroid the size of a grain of sand, if going fast enough can be lethal.

As for the rest, I will have to hope my video recorder works, as I will be away next week. 8-[

kucharek
2004-Nov-12, 09:18 AM
1) A nuclear reactor in space
The only people I know who got away with this were the Russians. In the west, no government would allow nuclear material to go into space incase of an accident on launch. This would be politically unacceptable and there would be massive protests and lawsuits to stop this.

A nuclear reactor is much less a danger than the Plutonium in RTGs and RTHs. An unused reactor is only very little radioactive, so even a catastrophic launch failure wouldn't do to much harm.


4) the Asteroid Belt
Ignoring the near miss, what about the micro-meteroids, those too small to be detected, but big enough to punch holes through the craft. A micrometeroid the size of a grain of sand, if going fast enough can be lethal.
From the point of view of a spcecraft, the belt isn't nearly non-existing. Before Pioneer 10/11, it was considered a danger and the scientists and engineers held their breath until they were through. Instrument showed, that it is pretty empty. Meanwhile, we had the Voyagers, Ulysses, Galileo and Cassini passing it without a hint of a danger.

Harald

Sticks
2004-Nov-12, 09:29 AM
1) A nuclear reactor in space
The only people I know who got away with this were the Russians. In the west, no government would allow nuclear material to go into space incase of an accident on launch. This would be politically unacceptable and there would be massive protests and lawsuits to stop this.

A nuclear reactor is much less a danger than the Plutonium in RTGs and RTHs. An unused reactor is only very little radioactive, so even a catastrophic launch failure wouldn't do to much harm.


Even so, in the mind of Jo Public, and their elected representatives and various pressure groups it is the greatest threat to human kind. Politics being what it is, it would be political suicide to allow this. The actual facts of the matter are irrelevant, only the perception counts, even if it is wrong by a parsec.

Van Rijn
2004-Nov-12, 11:52 AM
Apparently, though, this craft is supposed to use a fusion reactor - quite a different animal than a fission reactor. Anyway, nuclear is an absolute requirement if people are to seriously explore the solar system. And the U.S. is starting to get serious about nuclear space again. Look at project Prometheus, for instance:

http://spacescience.nasa.gov/missions/prometheus.htm

Hopefully, by the time we could build a fusion spacecraft, there won't be quite as much of a hysterical reaction to anything nuclear in this country.

Sticks
2004-Nov-12, 02:21 PM
If I recall, every time they try and send up anything with a small nuclear component, someone rushes to court to get an injuction on the basis that should the rocket explode all life will be extinguished by the debris.

Any politician with any political sense will do all in his power to block such advances, so he can present himself as defending the environment from mad scientist bent on world destruction.

And it will help him get elected.

Would you like to live next to a site where they are sending these things up, where there is a chance your home will be irradiated when their over priced and exravegant wastes of public money projet go boom, as it most certainly will. :roll:

Our minds are made up, don't bother us with the facts

dummy
2004-Nov-12, 03:01 PM
My DVD of the miniseries arrived today and I watched it again all the way through. I won't reveal anything that'd spoil it (since the last part of the show won't be shown on tv till next tuesday).

I thought it was a pretty interesting look at how human space flight would be and the effects were really good. The only slight problem I had with the series is that it felt as if they added a sense of danger and drama to every sub mission just to try and keep people interested. I'd have preferred a more scientific-documentary style approach than a 'reel in the viewers with tension' one, but I guess the latter gives higher ratings.

One last minor criticism; was it just me or were a few of the actors too exaggerated to be believable (the science director, 'Alex lloyd' in particular)? Overall though I thought it was excellent series depicting space flight that could be scientifically/technologically feasible in the near future.

JohnD
2004-Nov-12, 06:46 PM
All,
Thanks for the discussion, maybe I was a bit too hard on them. Goodish science seems to be the consensus.

John

PS Except for Sticks - magnetic fields and high voltage cable cause leukemia? The trouble is that if you look hard enough in any population you will find 'clusters' of anything you are looking for.

See Br J Cancer 2000 Sep;83(5):692-8 A pooled analysis of magnetic fields and childhood leukaemia. Quote "In summary, the 99.2% of children residing in homes with exposure levels < 0.4 microT had estimates compatible with no increased risk, while the 0.8% of children with exposures >/= 0.4 microT had a relative risk estimate of approximately 2, which is unlikely to be due to random variability. The explanation for the elevated risk is unknown, but selection bias may have accounted for some of the increase. " This study is a 'metanalysis' including the results of nine earluier studies, over 3000 children WITH leukemia and 300 without.

Or better still: Br J Cancer 2000 Dec;83(11):1573-80
Childhood cancer and residential proximity to power lines. UK Childhood Cancer Study Investigators. 3380 cases, 3390 matched controls. Quote "There was no evidence that either proximity to electrical installations or the magnetic field levels they produce in the UK is associated with increased risk of childhood leukaemia or any other cancer."

That's articles published in B.J.Cancer, not the Generating Board Gazette, or the Earth Huggers weekly. Sorry, but this is a 'Bad Science' Forum!
J.

johnwitts
2004-Nov-12, 11:31 PM
If only to see what Jay Utah makes of it :lol:

For those outside the UK, you will have to settle for this link (http://www.bbc.co.uk/sn/tvradio/programmes/spaceodyssey/)



Or you could try this.

http://www.uknova.com/browse.php?page=4

It's at the bottom of the page. Or it may have moved to the next page by now.

Van Rijn
2004-Nov-13, 01:05 AM
Would you like to live next to a site where they are sending these things up, where there is a chance your home will be irradiated when their over priced and exravegant wastes of public money projet go boom, as it most certainly will. :roll:

Our minds are made up, don't bother us with the facts

Heh. Sure, there are always the woo-woos. A bit off topic, but near my city there is a farm of huge fuel tanks. After 9/11 it occured to somebody that they could make a good target for terrorists. There was minimal security, and one guy with a rocket launcher could probably blow the whole farm up. Soon after that came out, I saw a number of interviews of people living near the tanks, absolutely shocked that nobody had ever told them of the potential danger of these ... massive fuel tanks practically sitting in their backyard. :roll:

Of course, they beefed up security somewhat, but these things are pretty common all over, in some cases hundreds or thousands could die, and they don't begin to have the security around a nuclear plant (and good luck firing a rocket at a reinforced concrete containment shell) but still, the news had a lot more bits on nuclear plant safety than fuel tank safety.

JohnD
2004-Nov-13, 10:39 AM
Van Rijn,
Shocked were they?
What did they think was in those tanks, beer?

By the way, thinking beer, a rocket into just a grain tower would probably make it explode. Not fall down, explode, the grain dust being the fuel in an air/fuel bomb.

Forgive me, but the US has been protected from the wild world for a long time. Here in the UK we know that a rocket into a tank farm is not necessary to kill a lot of people and is pretty unlikely. It is so much easier to build a bomb into a car and park it in a high street (shopping mall) or leave a bomb in a litter bin to kill even more - Omagh, Manchester, London Docklands, Warrington to name merely four horrors. For ages, there have been posters in the London Underground advising people to report suspicious packages, and litter bins in UK city centres are bomb resistant (blast goes up, not out). That's just in the UK. Madrid, Pakistan, India, Bali, Nairobi, Jakarta. Iraelis and Arabs get bus bombs and rockets into their houses. Yes, the US has had car bombs, at Oklahoma City and at the World Trade Centre, before 9/11, but the rest of the world has been living with this level of violence for long time.

And people worry about power cables.

John

Sticks
2004-Nov-13, 03:26 PM
Van Rijn,
And people worry about power cables.

John

And Mobile phone masts, lets not forget them :P

Richard of Chelmsford
2004-Nov-17, 10:39 AM
The next episode was on last night..not got much time, but here's one or two points.

Some of it was a bit vague and unclear, just noise, flashy goings on and mutterings you couldn't hear.

Plus one astronaut (female) landed on Io and managed to make a complete cock-up of her visit (typical! :lol: )

The rings of Saturn are OK. Looked like superstrings.

But the best bit by far was the landing on Pluto..first time I've ever seen anything like that in a sci-fi context.

The surface was flat ice with black rocks sticking up here and there. In the sky was Charon, very big, close and a kind of murky white. It was daytime, but the sky was like a gloaming, and the sun was still visible as a sun (not just a big star) but the geezer covered it up with his finger.

Plus he complained about the cold coming through his boots.

Pluto chilblains eh?

Gotta go.

JohnD
2004-Nov-17, 10:25 PM
All,
The second episode suffered from script writer's desperation.

A crew member died - I never did understand what from - I must have fallen asleep for that bit. But it did set the scene for some tearjerking scenes as his wrapped body floated away in a space burial in the Rings of Saturn.

That Io landing - same crits as for the Venus landing, plus. They could have had no idea of the surface nature, only observation. Before Moon probes landed, or rather crashed, there was serious worry that the maria were full of dust like quicksand. See AC Clarke " A Fall of Moondust". Lots of heavily volcanic regions on Earth have a thin crust over extremely hot and unstable undersoil. People have died from falling through.
Though you are either heavily ironic or misogynistic about the female character whose mission was cut short by her controllers (aka script writers).

And that comic, sorry, COMET interlude. First, they find a comet out in the region of Pluto. How? Comet cores are tiny in an ENORMOUS empty space. Then they match orbits with it, just before it starts outgassing from the Sun's heat. Predictable or not? Then, the gravel storm that results causes several penetrations of the spacecraft cabins AND the chest of a crew member. Cue for lots of ER style shouting. Oh, come on. Meteoric dust could penetrate a space craft, if their orbits intersected so that their relative speeds were high enough. But the comet and Pegasus were in the same orbit. Do we accept that an outgassing comet could drive gravel fast enough for penetration?

Lastly, if the Pegasus needed to aerobrake in Jupiter's atmosphere to make orbit, how did it slow down enough to make Earth orbit after falling three BILLION miles towards the Sun? I can't work out how fast it would be going, but it would be FAST.

John

eburacum45
2004-Nov-18, 08:36 AM
That chap was exposed to a lethal dose of solar radiation in the first episode, like that lass in Stephen Baxter's Titan.
In many ways the voyage reminded me of Titan; except that they didn't land on the clouded moon...
which incidentally must be about the coldest place in the Solar system to go in a space suit, as you would lose heat rapidly to the dense, cold atmosphere.

Hmm.
When the russian guy got a piece of comet in his lung, and experienced decompression, surely the decompression would have made the wound hideously complicated?

Ah well- it all happened so quickly you never got to find out.

JohnD
2004-Nov-18, 11:40 PM
eburacum,
Good point! One that I didn't spot and the script writers didn't mark up - maybe a bit medical.
A penetrating chest wound is likely to cause a pnuemothorax - air in the chest between lung and chest wall. The lung collapses, but the patient will manage for a while thanks to the evolved redundancy of mammal anatomy -they have plenty of lung tgissue still working. However, sometimes the pneumothorax may become "tension", if there is a flap valve type tear in the lung. Breathing pushes air into the chest outside the lung and it cannot get out. Increasing pressure forces the central compartment of the chest, the mediastinum containing th heart and major blood vessels, over the opposite side, compressing the heart, vessels and remaining lung. This can be rapidly fatal.
In a decompressing spacecraft, ANY pneumothorax will rapidly become a "tension" pneumothorax, as the air in the chest expands against the falling external pressure.
Perhaps the ER shouting was correct!
John

kucharek
2004-Nov-19, 07:11 AM
It aired yesterday on German tv, all in one part.
I've not finally decided if it was good or bad, depends a little bit on which hat I wear.
So, I for now stay on the technical side. :)
-The plotted trajectories were often beyond everything you could fly with this craft. They used relatively short impules to change trajectories, not permanent low thrust, which possibly could explain some.
-Beyond Mars, they got rid of the solar panels, because they were not any longer efficient. But that would mean that they must have some other source of electrical energy, too. And if they have a power source that is sufficient for the part beyond Mars, which was some 5 of the 6 years, then why bother to take solar collectors at all.
-When launching from Venus, pretty soon after launch they announce "pitchover". That's okay when launching from a planet without an or with a relatively thin atmosphere. From Venus, you'd go a longer way straight up to get out of the thick atmosphere before you go to use some energy to get orbital speed
(BTW, many dialogues sounded pretty familiar from Apollo flights. And that wishlist of the crew sounded much like the Skylab-4 revolt).
-They say the aerobraking manoeuvre at Jupiter may build up up to 15 Gs. The spacecraft didn't look like being able to withstand such loads.
-How would they break at Earth when returning from Pluto. They would be pretty fast and so would have not very much time for an aerobraking.
-One of the first things Armstrong did on the Moon was grabbing a contingency sample. Why didn't they do it on Io?
-Was it always the same lander they gave different names depending on where they landed? Using a Venus lander to land on Mars would be pretty silly.
-During Mars landing, they put out a chute while the craft still had a heated shockwave.
- During the fly-by of the sun, the shield was alwas oriented towards the sun. The best time for the thrust manoeuvre would be at perihel, but then the thrust direction would be perpendicular to the direction of travel.
-The asteroid belt is too full with asteroids... But I liked the wry remark that they named them "Hybris" and "Desaster".
-When they drove on Mars to Valles Marineries, mission control had the rover on their screens traveling along. Who held the camera? (Obviously, the movie is fake).


-They made good use of the Cupola (http://www.esa.int/export/esaHS/ESA65K0VMOC_iss_0.html). Maybe they used the one that never made it to the ISS on the Pegasus.

Maksutov
2004-Nov-19, 07:44 AM
1) A nuclear reactor in space
The only people I know who got away with this were the Russians. In the west, no government would allow nuclear material to go into space incase of an accident on launch. This would be politically unacceptable and there would be massive protests and lawsuits to stop this.

A nuclear reactor is much less a danger than the Plutonium in RTGs and RTHs.
Which means it's close to 100% safe, since the way the plutonium is configured in an RTG provides a reliable safety margin for even the most violent catastrophes.


An unused reactor is only very little radioactive, so even a catastrophic launch failure wouldn't do to much harm.[edit]

As is the case with RTGs.

Maksutov
2004-Nov-19, 08:06 AM
If I recall, every time they try and send up anything with a small nuclear component, someone rushes to court to get an injuction on the basis that should the rocket explode all life will be extinguished by the debris.
Some groups attempt to do this, but have failed in every instance. Back in 1997 various groups, and Dr. Michio Kaku, tried to do that very thing with the Cassini launch. The success of their attempts can be seen by looking at the beautiful pictures and incredible data currently being sent to Earth from Saturn.


Any politician with any political sense will do all in his power to block such advances, so he can present himself as defending the environment from mad scientist bent on world destruction.
None have.


And it will help him get elected.
Hasn't happened yet.


Would you like to live next to a site where they are sending these things up, where there is a chance your home will be irradiated when their over priced and exravegant wastes of public money projet go boom, as it most certainly will. :roll:
No problem here. In fact, I lived near where the nuclear materials were being produced and fabricated. Additionally, I worked at the facility where the nuclear materials were being produced and fabricated. Finally, the department I worked for was responsible for assuring the quality of these materials and the safety of not only the workers there, but the surrounding population and the populations where these materials were used, including the launch sites.

I suggest you seriously consider a steel-reinforced roof over your head or moving to a cave. Not to protect yourself from an exploding rocket, though. The likelihood of your being done in by a meteorite landing where you live is many factors more probable than your being even slightly injured by a space probe that is nuclear powered.


Our minds are made up, don't bother us with the facts
That is well-represented in your post. But as Jay's quote of John Adams states, "Facts are stubborn things."

Maksutov
2004-Nov-19, 08:13 AM
[edit]That Io landing - same crits as for the Venus landing, plus. They could have had no idea of the surface nature, only observation. Before Moon probes landed, or rather crashed, there was serious worry that the maria were full of dust like quicksand...

The Ranger probes crashed intentionally. The Surveyor probes soft-landed.

astrosapien
2004-Nov-19, 09:21 AM
I also saw it last night. In view of the fact that normally space provides the setting for movies like "Armageddon" or far future stuff like "Star Trek" (which I absolutely don't like, I have to admit), I was rather surprised when a movie (or series) with a quite science based approach was announced.


-One of the first things Armstrong did on the Moon was grabbing a contingency sample. Why didn't they do it on Io?
That's what I was thinking. But wasn't Armstrong reminded to do so? Maybe she forgt?
In the case of Io - a quite unstable world - wouldn't it have been better to use a robot? The robot could be controlled from the orbiting spacecraft in real time, thus allowing the human operator of the robot to react to unexpected events accordingly. The point that sending humans to the planets' surfaces was made several times - and with the example of the "failed" Venera mission, they had an important argument for that. But obiously there are circumstances, where sending a robot is safer.


-Was it always the same lander they gave different names depending on where they landed? Using a Venus lander to land on Mars would be pretty silly.
I had the impression that they had several bays for different landers and the lander looked different. Refitting the lander each time with a descent stage, refueling it and rigging it according to the needs dictated by the target object's gravity, atmoshere etc. - I guess that would be to difficult to be done in space. Although they had enough time during transits. In any case that means they carried a lot of stuff around with them. Which raises the question: what is better? A mission like this - comparable to Magellan's, Cook's or the Beagle's voyages, where the whole solar system is traveleld and a lot of stuff has to be transported? Or individual missions to each planet (or planets, I guess when visiting Saturn, you might stop by Saturn), where only the landing craft and other equipment for the specific mission is being carried?
And: a huge spacecraft that might require repair during transits, quite a number of difficult missions, probably a lot of samples to be examined during the voyage, the high risks that someone dies or is incapacitated to fulfill his or her task - and a crew of five? The fantastic five?
However, I still liked the movie. At first, I doubted that any suspense would build, but in the end it turned out that it has not a clean Hollywood mission, but it depicted the problems missions of this kind entail. And it gave the audience an idea what amazing things are out there - just waiting to be explored. I think it was good to win people over for the cause of space exploration.

JohnD
2004-Nov-19, 11:42 AM
Astrosapien,
Thanks - yes, it was better to have a 'hopeful' rather than disaster based space story. And maybe I was comparing it too closely with, say Apollo13. That had a cracking story line, even if we knew the ending, must have cost a LOT more to make and was, to some extent, a prolonged commercial for NASA, so lots of extra support. I don't know if ESA supported Oddyssy, beyond a surplus Cupola!
John

Matsutov,
Crash/Land - thanks for reminding me which probe did which. I couldn't remember and wanted to make the point that the crashes gave information used to enable the landing.

All in all - 8/10?
John

johnwitts
2004-Nov-21, 12:32 AM
I found both episodes good. Although we can pick holes, like with everything, the programme was on during mainstream hours on BBC1 in the UK, and midweek also.

When the miniseries 'From the Earth to the Moon' was shown, it was on Channel 4, and at midday on a Sunday (I think, anyway, it was at the weekend), and was not advertised at all. I stumbled upon it accidentally, just videoing it because it had 'Moon' in the title. What a gem that was!

Space Odyssey was meant for mainstream viewing, so had to be a little 'hyped'. There were a lot of ads for it in the weeks beforehand. I also think that the message was not to show how a mission would be done, but to show what's out there with the Pegasus being a device to show that, much as the Enterprise was a device for getting people into situations that they had to cope with each week. It doesn't really matter how it works, but what it achieves.

Space Odyssey was good because it showed that the crew would face the real danger of radiation on that long a journey. For a mainstream audience, you need to show that places are potentially dangerous, not just state that temperatures and pressures are such and such, but really show people struggling with what's going on.

Drama? Yes. But with a few bits of interesting science thrown in.

Sticks
2004-Nov-22, 10:39 PM
I suggest you seriously consider a steel-reinforced roof over your head or moving to a cave. Not to protect yourself from an exploding rocket, though. The likelihood of your being done in by a meteorite landing where you live is many factors more probable than your being even slightly injured by a space probe that is nuclear powered.


Our minds are made up, don't bother us with the facts
That is well-represented in your post. But as Jay's quote of John Adams states, "Facts are stubborn things."

I suspect I was a tad too subtle in my sarcasm and cynicism here. Anything with the word "nuclear" in it brings all sorts of Eco-alarmists out of the woodwork

Ilya
2004-Nov-23, 01:01 AM
If I recall, every time they try and send up anything with a small nuclear component, someone rushes to court to get an injuction on the basis that should the rocket explode all life will be extinguished by the debris.


"Someone" does, yes. And they always fail.



Any politician with any political sense will do all in his power to block such advances, so he can present himself as defending the environment from mad scientist bent on world destruction.

Not a single member of Congress did anything of the kind. A few (including John Kerry) voted to kill Cassini project, but it is unclear whether it was for environmental or budgetary reasons.

eburacum45
2004-Nov-23, 03:26 PM
They had a differently designed lander for each planet;
http://www.bbc.co.uk/sn/tvradio/programmes/spaceodyssey/pegasus.shtml
the Orpheus for landing on Venus, the Ares for landing on Mars, the Hermes for Io, the Clyde for Pluto and the Messier for the comet.

I am most interested in the Orpheus; such a powerful aerospike engine could be used to escape the Earth's atmosphere, if it were feasible.
Somehow I would imagine the rocket would be bigger-
it needs to be as powerful as an Atlas rocket at the very least.