Author Topic: Apollo Q&A  (Read 138739 times)

Offline butters

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Re: Apollo Q&A
« Reply #20 on: 07/20/2009 02:59 AM »
Mine may be a little of a bad question but I have always wondered. How did the Apollo crews access the SM? They had their seats behind them and under them they had the solid heat shield. Also how did they access the LM? They had the panels in front of them. Diagrams and pictures would be very helpful.

Sorry if these questions sound kinda dumb.

Thanks

Apollo SM had no crew-accessible volume, only conduits for power, water, oxygen, and comms to/from the CM. 

LM was accessible through a forward docking tunnel aligned with the axis of symmetry.  The crew couches and control panels were offset to one side of the vehicle (toward the hatch) so that the axis of symmetry would be just beyond the CM pilot's feet when seated in the center couch.  The control panels didn't extend much beyond waist-level, so the crew could slide feet-first out of the couches, clear the control panels, and then stand up with their head in the docking tunnel.  The side of the capsule opposite the hatch/heads is an equipment bay, so while the docking tunnel is in the center of vehicle, from the inside it may not seem that way at first glance.
« Last Edit: 07/20/2009 03:07 AM by butters »

Offline Aobrien

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Re: Apollo Q&A
« Reply #21 on: 07/20/2009 03:02 AM »
Wow well that makes everything seem different. On Apollo 13 which I know makes everything look big but it seemed like the SM was an extension to the CM.

Well thanks. My mind is all mixed up now!
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Offline C5C6

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Re: Apollo Q&A
« Reply #22 on: 07/20/2009 11:39 PM »
I would like to know about the micrometeoroid impact probability and the dangerous physical phenomenons the astronauts where exposed to (cosmic rays, radiation, etc).

Lots of people argue that we never went to the moon because of these things... I have no doubt we went to the moon, but would really like to know more about this since I know nothing...

Offline Jorge

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Re: Apollo Q&A
« Reply #23 on: 07/21/2009 12:00 AM »
I would like to know about the micrometeoroid impact probability and the dangerous physical phenomenons the astronauts where exposed to (cosmic rays, radiation, etc).

Lots of people argue that we never went to the moon because of these things... I have no doubt we went to the moon, but would really like to know more about this since I know nothing...

The quick and dirty summary:

Van Allen belts - occurred soon after TLI and soon before entry, so velocity was still relatively high (passed through belts quickly); during outbound leg crew was confined to the (relatively) better shielded CM to minimize exposure.

Solar flares - just plain lucky that one didn't occur during an Apollo mission. There was one observed flare (between 16 and 17, I believe) that would likely have killed a crew had there been one up at the time.

Cosmic rays - crew undoubtedly took doses; effects minimized due to short missions.

Micrometeoroids - odds of impact very low over mission duration.

Bottom line is that future missions will still need to get crews through the Van Allen belts quickly (rules out low-thrust propulsion for crew) and will need better shielding for long-duration surface stays.
JRF

Offline ugordan

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Re: Apollo Q&A
« Reply #24 on: 07/21/2009 12:54 AM »
Cosmic rays - crew undoubtedly took doses; effects minimized due to short missions.

A notable effect of this were sporadic, faint flashes of light in the astronauts' eyes as high energy cosmic rays struck their retinas. Even with eyes closed, of course. A human version of radiation noise we see in digital cameras in space.

« Last Edit: 07/21/2009 12:55 AM by ugordan »

Offline Archibald

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Re: Apollo Q&A
« Reply #25 on: 07/21/2009 06:43 PM »
I would like to know how the Apollo 11, 12, 14 are similar to Apollo 15, and also how they differ from Apollo 15.

 :)

Apollo mission types were referenced with letters - A to J. Each letter designed a different mission profile.

Of course this was in 1961-1963. Many events, such as the Apollo 1 fire, wrecked the ordonnance.

In the end Apollo 11 was a "G" mission - basically a lunar landing, period.

Apollo 12/13/14 and original 15 were "H" missions - more capable than Apollo 11. More time on lunar surface, for example. Still no rover.

Apollo 16 /17/18 /19/20 were  "J" missions - long stays, lot of science, lunar rover for more mobility.

Three Apollo missions were cut in January and September 1970. Because the hardware had already been built, Apollo 15 used the said hardware and was switched from a "H" to a "J" profile, along Apollo 16 and 17.
The "H" LM was never flown.

So according to performance it would be something like

Apollo 11 > Apollo 12 /13 /14 > Apollo 15 / 16 /17

Offline glen4cindy

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Re: Apollo Q&A
« Reply #26 on: 07/22/2009 02:31 AM »
Mine may be a little of a bad question but I have always wondered. How did the Apollo crews access the SM? They had their seats behind them and under them they had the solid heat shield. Also how did they access the LM? They had the panels in front of them. Diagrams and pictures would be very helpful.

Sorry if these questions sound kinda dumb.

Thanks

I know there was 1 or 2 missions where the Command Module Pilot did a space-walk toward the end of the mission and before they separated from the SM, where he retrieved a film magazine and possibly other things but I think it was only on 1 or 2 missions.

Offline Jorge

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Re: Apollo Q&A
« Reply #27 on: 07/22/2009 02:43 AM »
Mine may be a little of a bad question but I have always wondered. How did the Apollo crews access the SM? They had their seats behind them and under them they had the solid heat shield. Also how did they access the LM? They had the panels in front of them. Diagrams and pictures would be very helpful.

Sorry if these questions sound kinda dumb.

Thanks

I know there was 1 or 2 missions where the Command Module Pilot did a space-walk toward the end of the mission and before they separated from the SM, where he retrieved a film magazine and possibly other things but I think it was only on 1 or 2 missions.

3, actually. All the J-series missions (15,16,17) had a SIM-bay in the SM and needed an EVA during transearth coast for the CMP to retrieve the data.

http://www.myspacemuseum.com/simbay.htm#III
JRF

Offline ginahoy

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Re: Apollo Q&A
« Reply #28 on: 08/05/2009 03:02 AM »
I just read that the cabin atmosphere in the Apollo CM was modified from 40% Nitrogen/60% Oxygen at sea level pressure to 100% pure Oxygen at 2 psi after the TLI burn. The amount of O2 at that point is probably similar to 10,000 feet MSL. However, I didn't realize humans would be happy at 2 psi, even if with pure O2.

Assuming one is wearing an O2 mask, how low does the pressure have to go before there would be detrimental effects?

Offline Jim

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Re: Apollo Q&A
« Reply #29 on: 08/05/2009 11:47 AM »
I just read that the cabin atmosphere in the Apollo CM was modified from 40% Nitrogen/60% Oxygen at sea level pressure to 100% pure Oxygen at 2 psi after the TLI burn. The amount of O2 at that point is probably similar to 10,000 feet MSL. However, I didn't realize humans would be happy at 2 psi, even if with pure O2.

Assuming one is wearing an O2 mask, how low does the pressure have to go before there would be detrimental effects?

It was 5 psia

Offline ginahoy

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Re: Apollo Q&A
« Reply #30 on: 08/05/2009 03:58 PM »
It was 5 psia

If you'll provide a reference, I'll edit the Apollo 1 Wiki page which currently reads:

"At launch the cabin atmosphere would be at sea-level pressure and consist of 60% oxygen and 40% nitrogen, lowering to 5 psi during ascent and gradually changing over to 100% oxygen at about 2 psi during the first 24 hours of the trans-lunar coast."
« Last Edit: 08/05/2009 04:01 PM by ginahoy »

Offline Hungry4info3

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Re: Apollo Q&A
« Reply #31 on: 08/12/2009 05:23 AM »
I'm building a functional model of the Apollo spacecraft. I would like to know more about how the command module separated from the service module toward the end of the mission. Especially how the device I have drawn an arrow to is related (I'm sorry, I am sure it hurts to read that for some v_v. What is it called?).

Thanks in advance =)

Offline Analyst

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Re: Apollo Q&A
« Reply #32 on: 08/12/2009 08:30 AM »
This is the SM-CM umbilical. I am sure it has a fancy name and acronym. It carries power, oxygen, commands etc. between the two modules. You don't want to run these lines through the heat shield and therefore go arround it.

Analyst

Offline Hungry4info3

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Re: Apollo Q&A
« Reply #33 on: 08/12/2009 08:33 AM »
This is the SM-CM umbilical. I am sure it has a fancy name and acronym. It carries power, oxygen, commands etc. between the two modules. You don't want to run these lines through the heat shield and therefore go arround it.

Yes, I knew what function it performed, I'm just unsure how command module separation occurred without the CM snagging up against it. Did the umbilical detach and rotate back?

Offline Analyst

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Re: Apollo Q&A
« Reply #34 on: 08/12/2009 08:37 AM »
Yes. Detach and rotate by less than 90 degress. The famous Apollo 13 picture of the SM (with the "whole side of the spacecraft missing") shows it quite nicely.

Analyst

Offline Hungry4info3

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Re: Apollo Q&A
« Reply #35 on: 08/12/2009 10:03 AM »
The famous Apollo 13 picture of the SM (with the "whole side of the spacecraft missing") shows it quite nicely.

Ah that must be this image.
I can sort of see it now, yeah. I didn't notice that before.

Thank-you for the replies  ;D

Offline jhf

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Re: Apollo Q&A
« Reply #36 on: 08/26/2009 06:51 PM »
Q:  In the movie Apollo 13 the actor playing Fred Haise calls out "SECO" at S-IVB shutdown.  I know it's Hollywood but that film is just about as close as Hollywood ever gets to accurate.

Does SECO make sense in that context; i.e. whether Haise said it or not, was the S-IVB used as a sustainer in some way during launch?  My understanding of sustainers (and orbital mechanics for that matter) is anecdotal at best.

A: there are a lot of questions in this thread about the atmosphere on Apollo.  From reading "The Partnership: A History of The Apollo-Soyuz Test Project", I came away with the notion that the Apollo spacecraft was only good for about 9psi pressure differential; i.e. they designed Apollo to use pure oxygen to save weight (as previously noted in this thread) and were unable to change it to a partial oxygen environment after Apollo 1 because the pressure vessel would burst at 9psi with a vacuum outside, and it was too late to change it.  Pure oxygen at 5psi is less of an issue than at the 19-some psi on Apollo 1 (14.7 psi + 5-ish).

[EDIT: clarify I was referring to pure oxygen]
« Last Edit: 08/26/2009 06:55 PM by jhf »

Offline Jim

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Re: Apollo Q&A
« Reply #37 on: 08/26/2009 07:19 PM »
  Pure oxygen at 5psi is less of an issue than at the 19-some psi on Apollo 1 (14.7 psi + 5-ish).


Apollo 1 was never at 19 psia.  The issue was that is was at 100% O2 at sea level pressure prelaunch, which was suppose to be vented down to 5 psia on orbit.

It was changed to 60 N2/ 40 O2 , at sea level pressure prelaunch, which was vented down to 100% O2 at 5 psia on orbit.
« Last Edit: 08/26/2009 07:19 PM by Jim »

Offline Jim

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Re: Apollo Q&A
« Reply #38 on: 08/26/2009 07:24 PM »
Q:  In the movie Apollo 13 the actor playing Fred Haise calls out "SECO" at S-IVB shutdown.  I know it's Hollywood but that film is just about as close as Hollywood ever gets to accurate.

Does SECO make sense in that context; i.e. whether Haise said it or not, was the S-IVB used as a sustainer in some way during launch?  My understanding of sustainers (and orbital mechanics for that matter) is anecdotal at best.

sustainer and SECO applies only to classic Atlas

SECO is used by Delta meaning second stage engine cutoff

But the term for SIVB on the Saturn V would be TECO.  SECO would only apply to the Saturn IB

Another movie screw up


Offline Jorge

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Re: Apollo Q&A
« Reply #39 on: 08/26/2009 08:02 PM »
Q:  In the movie Apollo 13 the actor playing Fred Haise calls out "SECO" at S-IVB shutdown.  I know it's Hollywood but that film is just about as close as Hollywood ever gets to accurate.

Does SECO make sense in that context; i.e. whether Haise said it or not, was the S-IVB used as a sustainer in some way during launch?  My understanding of sustainers (and orbital mechanics for that matter) is anecdotal at best.

sustainer and SECO applies only to classic Atlas

SECO is used by Delta meaning second stage engine cutoff

But the term for SIVB on the Saturn V would be TECO.  SECO would only apply to the Saturn IB

Another movie screw up



The S-IC and S-II stages both had early Center Engine Cutoff (S-II a bit earlier than planned on 13) and I imagine "CECO" would be pronounced the same as "SECO".

Still a movie screwup since they had Haise calling it out for the wrong stage.
JRF

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