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View Full Version : Are shuttle altitudes in feet, or meters?



tracer
2004-Mar-27, 09:04 PM
While watching my DVD of everyone's favorite *cough* movie, The Core, I noticed something in the space shuttle landing sequence. Just before re-entry began, Beck tells Houston that they're at "400,000 feet" altitude. Later, when they're off-course descending toward Los Angeles, Iverson reports that they're at "One five thousand feet."

Now, I remember hearing somewhere that Apollo was the last manned NASA program to use feet and miles and pounds, and that all subsequent manned missions (e.g. STS) use metric units exclusively. However, I also know from my own experience that both U.S. civilian and U.S. military aviation still use feet for altitude, and the landing of the space shuttle is more like an aviation mission than a space mission.

So ... what units does the real space shuttle use for altitude during re-entry and descent? Do they use feet, or do they use meters?

Glom
2004-Mar-27, 09:16 PM
I know unmanned use metric exclusively but I thought NASA MSF still uses imperial.

scottmsg
2004-Mar-27, 11:39 PM
When the space shuttle is below 60,000 feet it enters Class A airspace and would use feet for its altitude as all other aircraft do (at least in the US). I imagine it would be a pain to switch between feet and meters at a critical point, so NASA would probably use feet for the entire mission.

Scott

Mr. X
2004-Mar-28, 02:23 AM
I know unmanned use metric exclusively but I thought NASA MSF still uses imperial.
Really... why the double standard?

Brady Yoon
2004-Mar-28, 02:29 AM
I think the United States uses the metric system for all measurements regarding science.

archman
2004-Mar-28, 03:08 AM
I think the United States uses the metric system for all measurements regarding science.

Well, being a scientist myself I can certify that as not being absolutely true! I see feet, miles, and gallon still used quite a bit in the journals... it IS frowned upon though.

Oh yeah, this is my first post on the board. I've been lurking for months, like a mouse.

ZaphodBeeblebrox
2004-Mar-28, 03:30 AM
I think the United States uses the metric system for all measurements regarding science.

Well, being a scientist myself I can certify that as not being absolutely true! I see feet, miles, and gallon still used quite a bit in the journals... it IS frowned upon though.

Oh yeah, this is my first post on the board. I've been lurking for months, like a mouse.

Welcome to The Board!

Now, become the Cat, Stalking its Prey!

John Kierein
2004-Mar-28, 02:12 PM
A couple of years ago I was working on a Navy high tech program that specified velocity in kiloknots!
Actually many high tech programs have gotten away from metric because tooling is still built in english units and all metric drawings have to be converted to english for fabrication by many low bidders. I work on lots of high tech jobs for a living and find all sorts of mixed units.

tracer
2004-Mar-28, 04:45 PM
Really? That's odd. I'd heard that in the electronics manufacturing industry, all dimensions have to be specified in millimeters -- if you give them a motherboard spec in inches, they won't build it.

And as far as the U.S. using the metric system for all measurements regarding science, I hasten to point out that the re-entry portion of a Shuttle mission doesn't really count as "science." All the sciency stuff associated with a Shuttle mission is done before they head back to Earth.

So, back to my original query: Would a shuttle pilot report to Mission Control that they were at "400,000 feet"?

Glom
2004-Mar-28, 04:50 PM
I was told by an electronics engineer at BAe that his dealings with Americans involve thousandths of an inch.

tracer
2004-Mar-28, 04:54 PM
Well, being a scientist myself I can certify that as not being absolutely true! I see feet, miles, and gallon still used quite a bit in the journals... it IS frowned upon though.
Back in grad school, my astro prof. told me about a guy who did his master's/doctoral thesis on the amount of alcohol molecules in some giant interstellar dust cloud. He reported the total volume of alcohol in units of shot glasses.

When his thesis committee objected, saying that a shot glass wasn't an S.I. unit, he replied, "Sure it is! It's a barn-parsec." ;)

tracer
2004-Mar-28, 04:56 PM
I was told by an electronics engineer at BAe that his dealings with Americans involve thousandths of an inch.
Oh, sure, go ahead, dash my hopes for a metric world why don't you!

hedin
2004-Mar-28, 06:19 PM
I do believe that the russians, and the former Soviet republics are the only ones using meters in aviation. To my knowledge every one else uses feet. This actually caused a mid air colission a few years back in India when a russian cargo plane collided with a 747. The russian pilot had made an error in his conversion causing the two planes to be at the same flight level.

QuagmaPhage
2004-Mar-28, 06:52 PM
I was told by an electronics engineer at BAe that his dealings with Americans involve thousandths of an inch.
Oh, sure, go ahead, dash my hopes for a metric world why don't you!
It's common that older PCB layout software uses thousandts of an inch, commonly called mils, as basic measurement unit. Newer software usually offers a choice between metric and mils but some firms will keep using mils because it is too much work converting old board designs to metric.

frenat
2004-Mar-28, 09:35 PM
So, back to my original query: Would a shuttle pilot report to Mission Control that they were at "400,000 feet"?

I would think the reporting would not be necessary as Mission Control should be be receiving the telemetry. Also unless they are getting the altitude from GPS, their regular aviation instruments would not be able to read 400,000 feet (they use air pressure and there is no appreciable air pressure at that altitude.) They may have another way of determining altitude but I think Mission Control would first be receiving the telemetry and second have them on multiple radar designed for that purpose.

Andreas
2004-Mar-29, 02:18 AM
I do believe that the russians, and the former Soviet republics are the only ones using meters in aviation. To my knowledge every one else uses feet.
That's because the ICAO (International Civil Aviation Organization) standardized it at that and most western states follow that. Certainly in commercial aviation, but around here every sailplane has instruments in meter (altitude), kilometer / hour (speed) and meter / second (vertical speed).

And before the end of WW2, there were more countries having metric aviation.

tracer
2004-Mar-29, 03:33 PM
around here every sailplane has instruments in meter (altitude), kilometer / hour (speed) and meter / second (vertical speed).
Hmmm ... I wonder if they'd be willing to go that final step and list airspeed in meters/second too. (km/h may be metric, but it sure as heck isn't S.I.)

tlbs101
2004-Mar-29, 10:33 PM
I am an electronics engineer for a large aerospace company. We design alot of electronic "boxes" for launch vehicles and satellites. Sorry to say, we are still using English inches to design and manufacture them.

All the Delta family, all the Atlas family, and Sea Launch vehicles that have our (partially my) designs are based (mechanically) on English units. I just asked one of our ME's and he confirmed this for me.

At least the electronic portions are based on Amperes, volts, and Ohms -- all SI units and derivations.


One of my physics teacher's favorite units of speed: furlongs per fortnight.

Andreas
2004-Mar-30, 03:01 AM
around here every sailplane has instruments in meter (altitude), kilometer / hour (speed) and meter / second (vertical speed).
Hmmm ... I wonder if they'd be willing to go that final step and list airspeed in meters/second too. (km/h may be metric, but it sure as heck isn't S.I.)
Historical reasons --- that's how it's always been done. :wink:

Besides, air speed is also used for navigation and you're not dealing in seconds there. Maybe it's more practical to have an hour based speed unit.

tracer
2004-Mar-31, 04:14 PM
At least the electronic portions are based on Amperes, volts, and Ohms -- all SI units and derivations.
Don't worry, I'm sure some red-blooded American is working on converting from Volts to BTUs-per-Coulomb. And then only because there's no foot-pound-Fahrenheit equivalent for the Coulomb.


One of my physics teacher's favorite units of speed: furlongs per fortnight.
ABE SIMPSON: "The metric system is a tool of the devil! My car gets 40 rods to the hogshead, and that's the way I likes it!"

hedin
2004-Mar-31, 05:19 PM
At least the electronic portions are based on Amperes, volts, and Ohms -- all SI units and derivations.
Don't worry, I'm sure some red-blooded American is working on converting from Volts to BTUs-per-Coulomb. And then only because there's no foot-pound-Fahrenheit equivalent for the Coulomb.


One of my physics teacher's favorite units of speed: furlongs per fortnight.
ABE SIMPSON: "The metric system is a tool of the devil! My car gets 40 rods to the hogshead, and that's the way I likes it!"


LOL so typical for old people. Im probably gonna end up that way.(hopefully many many nanoseconds from now) :wink:

calliarcale
2004-Mar-31, 10:03 PM
So ... what units does the real space shuttle use for altitude during re-entry and descent? Do they use feet, or do they use meters?

Going purely from memory, I seem to recall they announce feet on the live broadcast. Sorry to dash anybody's hopes of a metric world. Then again, this may be simply because most American listeners will be more familiar with feet. (I apologize for my countrymen. We're just metricaphobic.)