Author Topic: Shuttle Q&A Part 5  (Read 1542553 times)

Offline ginahoy

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Re: Shuttle Q&A Part 5
« Reply #280 on: 07/29/2009 12:45 am »
1)What is METOX?

Metal Oxide == refers to the technology used for recyclable CO2 scrubbing canisters. The crew bakes them in a special oven to release the CO2 to the station's atmosphere, which is then removed by one of the central scrubbers.

Quote
2) why were two coverings taken off parts of pieces, then jettisoned into space?   Where they dropped? I mean they could have been brought in and put with the other "space junk.

This question came up in one of the briefings. Those that weren't needed were thrown overboard to save the time/hassle of trying to wiggle them into a storage bag. Because of their low mass, they will reenter in a matter of days, IIRC, rather than becoming a long-term debris risk.
« Last Edit: 07/29/2009 12:57 am by ginahoy »

Offline ginahoy

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Re: Shuttle Q&A Part 5
« Reply #281 on: 07/29/2009 12:57 am »
Why is an astronaut always on capcom, I mean they all speak english don't they?

Not sure who you mean by "they", but astronauts are uniquely qualified to serve as the communications liaison between the on-orbit crew and the flight control team. They're not just reading a script. During shuttle missions, they are often members of the back-up crew, so they will be familiar with all aspects of the mission.

It is my observation that capcoms during shuttle missions are always astronauts while ISS stage operations sometimes have non-astronaut  capcoms. That's probably just a function of the large number of hours during stage operations.

Offline padrat

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Re: Shuttle Q&A Part 5
« Reply #282 on: 07/29/2009 01:39 am »

Tests have shown hydrogen can give you a blast because it can mix then go off. 

in about 90% of the jobs that we do one of the first steps we do before we open the system is to verify that the system is at less than 1% H2 and less than 1% O2. Then while the system is open it is purged with GN2/GHe to prevent air intrusion. The reason is to prevent what is called an "in-line detonation" which can, if severe enough, damage or destroy equipment. I've seen photos of one such detonation that occured in a vent line at Stennis. Every 90 degree turn in the line was split or blown out from the shockwave traveling through the line, since the shockwave resists sharp turns. Earlier this year we actually had a detonation for the first time that anyone could remember. We were between waves during tankers and got shut down for weather. It was an extremely windy day (at least 30 knot sustained winds) with a hot (H2 rich) vent line since we vent to the flare stack during tankers. We were in the shop and kept hearing this weird noise that sounded like something hitting the side of the shop, about every 15 mins or so, but couldn't figure out what it was. What was happening was that due to the low pressure in the line from no flow the wind was blowing out the flame and actually blowing air back into the line. It would mix, then the pressure would finally build enough to push the mixture out of the line, where it would ignite when it hit the propane igniters. We finally got the all clear to continue so we went back out and continued tanker offload. When tankers were done flow slowed again, but with an enriched line the wind blew it out again. This time when it lit it sounded like a bomb going off. It actually knocked all of the frost off the line all the way back to the storage area. Definately got our attention. There was alot of leak checking and inspections after that to make sure nothing was damaged.
« Last Edit: 07/29/2009 01:42 am by padrat »
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Offline Jorge

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Re: Shuttle Q&A Part 5
« Reply #283 on: 07/29/2009 01:44 am »
Why is an astronaut always on capcom, I mean they all speak english don't they?

Not sure who you mean by "they", but astronauts are uniquely qualified to serve as the communications liaison between the on-orbit crew and the flight control team. They're not just reading a script. During shuttle missions, they are often members of the back-up crew, so they will be familiar with all aspects of the mission.

Just to clarify, *ISS* CAPCOMs during shuttle missions are often members of the ISS backup crew. Shuttle missions themselves do not have backup crews.
JRF

Offline Danny Dot

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Re: Shuttle Q&A Part 5
« Reply #284 on: 07/29/2009 02:40 am »

Tests have shown hydrogen can give you a blast because it can mix then go off. 

in about 90% of the jobs that we do one of the first steps we do before we open the system is to verify that the system is at less than 1% H2 and less than 1% O2. Then while the system is open it is purged with GN2/GHe to prevent air intrusion. The reason is to prevent what is called an "in-line detonation" which can, if severe enough, damage or destroy equipment. I've seen photos of one such detonation that occured in a vent line at Stennis. Every 90 degree turn in the line was split or blown out from the shockwave traveling through the line, since the shockwave resists sharp turns. Earlier this year we actually had a detonation for the first time that anyone could remember. We were between waves during tankers and got shut down for weather. It was an extremely windy day (at least 30 knot sustained winds) with a hot (H2 rich) vent line since we vent to the flare stack during tankers. We were in the shop and kept hearing this weird noise that sounded like something hitting the side of the shop, about every 15 mins or so, but couldn't figure out what it was. What was happening was that due to the low pressure in the line from no flow the wind was blowing out the flame and actually blowing air back into the line. It would mix, then the pressure would finally build enough to push the mixture out of the line, where it would ignite when it hit the propane igniters. We finally got the all clear to continue so we went back out and continued tanker offload. When tankers were done flow slowed again, but with an enriched line the wind blew it out again. This time when it lit it sounded like a bomb going off. It actually knocked all of the frost off the line all the way back to the storage area. Definately got our attention. There was alot of leak checking and inspections after that to make sure nothing was damaged.

And some people think we will be putting this stuff in cars at gas stations someday.  I think not. 

Danny Deger
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Offline oxford750

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Re: Shuttle Q&A Part 5
« Reply #285 on: 07/29/2009 02:53 am »
1)What is METOX?

Metal Oxide == refers to the technology used for recyclable CO2 scrubbing canisters. The crew bakes them in a special oven to release the CO2 to the station's atmosphere, which is then removed by one of the central scrubbers.

Quote
2) why were two coverings taken off parts of pieces, then jettisoned into space?   Where they dropped? I mean they could have been brought in and put with the other "space junk.

This question came up in one of the briefings. Those that weren't needed were thrown overboard to save the time/hassle of trying to wiggle them into a storage bag. Because of their low mass, they will reenter in a matter of days, IIRC, rather than becoming a long-term debris risk.

Thanks for answering my questions ginahoy.

As for question 2: Am I to assume then that something that is bigger and has a higher mass will stay in orbit longer?

Makes no sense to me, if that is the case.

Oxford750

Offline oxford750

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Re: Shuttle Q&A Part 5
« Reply #286 on: 07/29/2009 03:07 am »
Why is an astronaut always on capcom, I mean they all speak english don't they?

Not sure who you mean by "they", but astronauts are uniquely qualified to serve as the communications liaison between the on-orbit crew and the flight control team. They're not just reading a script. During shuttle missions, they are often members of the back-up crew, so they will be familiar with all aspects of the mission.

It is my observation that capcoms during shuttle missions are always astronauts while ISS stage operations sometimes have non-astronaut  capcoms. That's probably just a function of the large number of hours during stage operations.

Thanks again ginahoy.

I just thought that "anybody" at mission control in Houston that works on the specific mission (i.e. STS-127) can speak to the astronauts as  most of MCC-H know the mission "like the back of tere hand",but you had good answer to things I never thought of.


oxford750

Offline Jorge

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Re: Shuttle Q&A Part 5
« Reply #287 on: 07/29/2009 03:42 am »
Why is an astronaut always on capcom, I mean they all speak english don't they?

Not sure who you mean by "they", but astronauts are uniquely qualified to serve as the communications liaison between the on-orbit crew and the flight control team. They're not just reading a script. During shuttle missions, they are often members of the back-up crew, so they will be familiar with all aspects of the mission.

It is my observation that capcoms during shuttle missions are always astronauts while ISS stage operations sometimes have non-astronaut  capcoms. That's probably just a function of the large number of hours during stage operations.

Thanks again ginahoy.

I just thought that "anybody" at mission control in Houston that works on the specific mission (i.e. STS-127) can speak to the astronauts as  most of MCC-H know the mission "like the back of tere hand",but you had good answer to things I never thought of.

Flight controllers are trained as specialists. Astronauts are generalists. A flight controller will not necessarily have any training in systems outside their particular console position. They know their systems like the backs of their hands, and they know how their system fits into the big picture of the mission, but that does not grant them particular insight into other systems nor to communicate those insights to the crew.
JRF

Offline Danny Dot

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Re: Shuttle Q&A Part 5
« Reply #288 on: 07/29/2009 03:49 am »
snip

Flight controllers are trained as specialists. Astronauts are generalists. A flight controller will not necessarily have any training in systems outside their particular console position. They know their systems like the backs of their hands, and they know how their system fits into the big picture of the mission, but that does not grant them particular insight into other systems nor to communicate those insights to the crew.

Why don't we just pump the flight loop up to the crew and let them sort that mess out  :o

Just kidding.  It takes years of training to learn to listen to that chatter. 

An experienced instructor might make a better capcom than an experienced flight controller.  At least the instructor speaks the language of the flight crews.

Danny Deger
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Offline ginahoy

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Re: Shuttle Q&A Part 5
« Reply #289 on: 07/29/2009 05:43 am »
As for question 2: Am I to assume then that something that is bigger and has a higher mass will stay in orbit longer?

Lightweight objects loose energy quicker due to atmospheric drag. Remember, there's enough atmosphere still present at 220 miles to cause the space station to require periodic reboost.

Offline oxford750

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Re: Shuttle Q&A Part 5
« Reply #290 on: 07/29/2009 06:08 am »
Why is thr ISS "red".

Oxford750

Offline oxford750

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Re: Shuttle Q&A Part 5
« Reply #291 on: 07/29/2009 06:35 am »
As for question 2: Am I to assume then that something that is bigger and has a higher mass will stay in orbit longer?

Lightweight objects loose energy quicker due to atmospheric drag. Remember, there's enough atmosphere still present at 220 miles to cause the space station to require periodic reboost.


So are you saying that two idenical cases in orbit, -one lighter than the other-,  that the lighter one will fall faster.

OR


something that is round and flat (ie a cover or blanket) will fall faster because of its shape?

Oxford750

Offline Danny Dot

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Re: Shuttle Q&A Part 5
« Reply #292 on: 07/29/2009 07:20 am »
As for question 2: Am I to assume then that something that is bigger and has a higher mass will stay in orbit longer?

Lightweight objects loose energy quicker due to atmospheric drag. Remember, there's enough atmosphere still present at 220 miles to cause the space station to require periodic reboost.


So are you saying that two idenical cases in orbit, -one lighter than the other-,  that the lighter one will fall faster.

OR


something that is round and flat (ie a cover or blanket) will fall faster because of its shape?

Oxford750

It is a combination of size, shape, and weight.  But for the most part, small objects slow down at a faster rate.  Having said this, a 100 pound object the size of a school bus will probably slow down faster than a 10 pound metal sphere.

Danny Deger
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Offline elmarko

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Re: Shuttle Q&A Part 5
« Reply #293 on: 07/29/2009 11:15 am »
Why is thr ISS "red".

Oxford750

I could be wrong but I think that means the system isn't pulling in any data for range and rate?

Offline Antares

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Re: Shuttle Q&A Part 5
« Reply #294 on: 07/29/2009 02:05 pm »
As for falling out of orbit, look up ballistic coefficient or ballistic number.

http://en.wikipedia.org/wiki/Ballistic_coefficient
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Offline padrat

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Re: Shuttle Q&A Part 5
« Reply #295 on: 07/29/2009 02:15 pm »

And some people think we will be putting this stuff in cars at gas stations someday.  I think not. 

Danny Deger

Well, I wouldn't necessarily say that. I'm one all for a hydrogen society. It will just take a learning and education process like it was for gasoline way back when. We will develop processes and safety guidelines, develop new specialized hardware and safety equipment. I'm sure there will be accidents and we will learn from them. It's just that, here, we work for a government entity that has it's own safety regulations, industry-wide safety regulations, and we are dealing with a much, much larger amount of commodity that most of the public will ever have to at one time.
« Last Edit: 07/29/2009 10:50 pm by padrat »
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Online kenny008

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Re: Shuttle Q&A Part 5
« Reply #296 on: 07/29/2009 05:24 pm »
A quick question on astronaut training:

When using the Shuttle Mission Simulator, does the crew periodically wear their ACES suits?  I'm sure they don't wear them for every session, but I'm curious to know whether they often get the chance to practice reacting to anomalies while wearing the full flight suit.  It seems like this can make quite a difference in their learned automatic responses if they practice in the simulator differently than when in actual flight.

Offline Jorge

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Re: Shuttle Q&A Part 5
« Reply #297 on: 07/29/2009 05:49 pm »
A quick question on astronaut training:

When using the Shuttle Mission Simulator, does the crew periodically wear their ACES suits?

Yes.
JRF

Offline darren1

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Re: Shuttle Q&A Part 5
« Reply #298 on: 07/29/2009 10:32 pm »
Ok, apologies for this but I HAVE looked (as much as I will at bed time :) ) , but when was STS-134 announced???  I thought the schedule went to STS-133 but the NASA site is showing an additional flight for launch on Sept 16th.  Cant believe I'm the 1st to see this but can not see a thread?????


Offline ChrisGebhardt

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Re: Shuttle Q&A Part 5
« Reply #299 on: 07/29/2009 10:42 pm »
Darren1,

Officially, about a year ago. It started out as the LON mission for STS-133 before being confirmed via an Act of Congress which mandated the delivery of AMS-2 to the ISS.  STS-134 is currently scheduled to launch BEFORE STS-133 in July 2010 on Endeavour with STS-133 on Discovery following in September 2010.   STS-335 (on Atlantis) is scheduled to be the LON flight for STS-133 now.
« Last Edit: 07/29/2009 10:49 pm by ChrisGebhardt »

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