Author Topic: What if the Apollo missions never left Earth orbit?  (Read 27906 times)

Offline Blackstar

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Re: What if the Apollo missions never left Earth orbit?
« Reply #40 on: 05/28/2009 01:54 pm »
Assuming a fairly benign failure in the S-IVB like no restart for TLI... I wonder if they would even have bothered with extracting the LM?

My assumption is that if they could not get out of Earth orbit, their first priority would be testing out the LM's systems in LEO.  However, there might have been obstacles to doing this.  Without a flight plan, I'm not sure how much they would have wanted to actually do with the LM, like firing its engines and such.  Maybe they would have just extracted it, run its systems, and then dumped it.

Offline DerekL

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Re: What if the Apollo missions never left Earth orbit?
« Reply #41 on: 05/28/2009 03:00 pm »
My assumption is that if they could not get out of Earth orbit, their first priority would be testing out the LM's systems in LEO.  However, there might have been obstacles to doing this.  Without a flight plan, I'm not sure how much they would have wanted to actually do with the LM, like firing its engines and such.  Maybe they would have just extracted it, run its systems, and then dumped it.

Was the PLSS/OPS (required for any spacewalks) stored in the CM or the LM?

Could the LM be flown remotely?  If it could be, then extracting it would mean they could target its re-entry and thus that of the RTG cask.

Offline Jim

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Re: What if the Apollo missions never left Earth orbit?
« Reply #42 on: 05/28/2009 03:10 pm »

1.  Was the PLSS/OPS (required for any spacewalks) stored in the CM or the LM?

2.  Could the LM be flown remotely?  If it could be, then extracting it would mean they could target its re-entry and thus that of the RTG cask.

1.  LM

2.  No, but the SIVB was controllable and depending on the failure could be deorbited by blowdown. 


Offline Blackstar

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Re: What if the Apollo missions never left Earth orbit?
« Reply #43 on: 05/28/2009 05:18 pm »
They could do a spacewalk without the PLSS, using the air hose (I forget the official term).  That's how they retrieved the film from the Pan Cam mentioned earlier.

Offline William Barton

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Re: What if the Apollo missions never left Earth orbit?
« Reply #44 on: 05/28/2009 05:33 pm »
They could do a spacewalk without the PLSS, using the air hose (I forget the official term).  That's how they retrieved the film from the Pan Cam mentioned earlier.

I have a vague memory of it being called an "umbilical."

Offline Jorge

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Re: What if the Apollo missions never left Earth orbit?
« Reply #45 on: 05/28/2009 05:34 pm »

Could the LM be flown remotely?  If it could be, then extracting it would mean they could target its re-entry and thus that of the RTG cask.

There was an Ascent Engine Arming Assembly (AEAA) that allowed remote firing of the ascent stage. This was used to deorbit the ascent stage after docking with the CSM in lunar orbit. However, the RTG cask was on the descent stage and there was no similar capability to remote-fire the descent engine.
JRF

Offline William Barton

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Re: What if the Apollo missions never left Earth orbit?
« Reply #46 on: 05/28/2009 05:35 pm »

1.  Was the PLSS/OPS (required for any spacewalks) stored in the CM or the LM?

2.  Could the LM be flown remotely?  If it could be, then extracting it would mean they could target its re-entry and thus that of the RTG cask.

1.  LM

2.  No, but the SIVB was controllable and depending on the failure could be deorbited by blowdown. 



There'd be enough fuel aboard a lunar CSM to do a retroburn, release the LM, and then to a posigrade burn to reestablish LEO for the CSM.

Offline edkyle99

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Re: What if the Apollo missions never left Earth orbit?
« Reply #47 on: 05/28/2009 07:35 pm »

Could the LM be flown remotely?  If it could be, then extracting it would mean they could target its re-entry and thus that of the RTG cask.

There was an Ascent Engine Arming Assembly (AEAA) that allowed remote firing of the ascent stage. This was used to deorbit the ascent stage after docking with the CSM in lunar orbit. However, the RTG cask was on the descent stage and there was no similar capability to remote-fire the descent engine.

Could the LM have been parked in a "safe" (higher) orbit using the ascent engine?  This would seem to be a better option than dropping an RTG into an atmospheric reentry.  Other RTGs are up there right now, orbiting the earth in relatively high orbits.  (Some of them we don't want to reenter because they were designed to disintegrate, spreading their fuel widely into the atmosphere.  It actually happened once, when a Thor-Able-Star carrying a Transit satellite failed.  About 1 kg of Plutonium 238 was lost off the equatorial east African coast to float down, somewhere).

 - Ed Kyle
« Last Edit: 05/28/2009 08:58 pm by edkyle99 »

Offline the_other_Doug

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Re: What if the Apollo missions never left Earth orbit?
« Reply #48 on: 05/28/2009 07:37 pm »
Starting with Apollo 12, the contingency plans included the details of how the LM would be used, what would be removed from LM storage (mostly cameras and film) prior to jettisoning it, etc.  I get the feeling that, for Apollo 11, they would have ad-hoc'ed the specific mission checkpoints if they had been forced into an alternate mission.  But it's obvious that they had made at least general plans as to what to do with the spacecraft and crew under a wide variety of malfunction conditions.

-the other Doug
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Offline DMeader

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Re: What if the Apollo missions never left Earth orbit?
« Reply #49 on: 05/28/2009 07:42 pm »

Could the LM have been parked in a "safe" (higher) orbit using the ascent engine?  This would seem to be a better option than dropping an RTG into an atmospheric reentry.  Other RTGs are up there right now, orbiting the earth in relatively high orbits.  (Some of them we don't want to reenter because they were designed to disintegrate, spreading their fuel widely into the atmosphere.  It actually happened once, when a Thor-Able-Star carrying a Transit satellite failed.  About 1 kg of Plutonium 238 was lost over or just beyond the equatorial Pacific to float down, somewhere).

 - Ed Kyle

The RTG cask was on the descent stage, ascent stage had to seperate to fire the ascent stage engine.

Offline Blackstar

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Re: What if the Apollo missions never left Earth orbit?
« Reply #50 on: 05/28/2009 07:47 pm »
Other RTGs are up there right now, orbiting the earth in relatively high orbits.  (Some of them we don't want to reenter because they were designed to disintegrate, spreading their fuel widely into the atmosphere.  It actually happened once, when a Thor-Able-Star carrying a Transit satellite failed.  About 1 kg of Plutonium 238 was lost over or just beyond the equatorial Pacific to float down, somewhere).

I think you're thinking of the Soviet reactors.  Off the top of my head the only RTGs in Earth orbit are on LES 8 and 9, and they are at very high orbits.  I think they also date from after the redesign and could survive reentry.

Offline the_other_Doug

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Re: What if the Apollo missions never left Earth orbit?
« Reply #51 on: 05/28/2009 07:47 pm »

Could the LM be flown remotely?  If it could be, then extracting it would mean they could target its re-entry and thus that of the RTG cask.

There was an Ascent Engine Arming Assembly (AEAA) that allowed remote firing of the ascent stage. This was used to deorbit the ascent stage after docking with the CSM in lunar orbit. However, the RTG cask was on the descent stage and there was no similar capability to remote-fire the descent engine.

Could the LM have been parked in a "safe" (higher) orbit using the ascent engine?  This would seem to be a better option than dropping an RTG into an atmospheric reentry.  Other RTGs are up there right now, orbiting the earth in relatively high orbits.  (Some of them we don't want to reenter because they were designed to disintegrate, spreading their fuel widely into the atmosphere).

 - Ed Kyle

Quick answer is no -- the RTG fuel was in a cask attached to the descent stage.  You have to jettison the descent stage before you can fire the ascent engine.  Ergo, nothing you do with the ascent engine can be used to park the descent stage in any kind of orbit.

As for remotely controlling the LM -- didn't the flight controllers have access to start and run programs in the LM's computer?  They could have brought up P40, right?  Maybe, though, they couldn't send a PRO signal at the correct time (or at all) to actually begin the engine start sequence.  (All of this discounts Apollo 5, on which LM-1 was specifically rigged to be able to be flown from the ground.)

-the other Doug
-Doug  (With my shield, not yet upon it)

Offline edkyle99

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Re: What if the Apollo missions never left Earth orbit?
« Reply #52 on: 05/28/2009 08:05 pm »

I think you're thinking of the Soviet reactors.  Off the top of my head the only RTGs in Earth orbit are on LES 8 and 9, and they are at very high orbits.  I think they also date from after the redesign and could survive reentry.

The Soviet reactors were designed to "safe" to higher orbits, but there are other, U.S. RTGs still in Earth orbit, I believe, on four early Transit satellites, on Nimbus 3, and on Triad 01-1X. 
http://nuclear.gov/space/neSpace2c.html

The SNAP-9A RTGs are of concern, because they were designed to "burn up" on reentry.  That means Plutonium 238 fallout - and quite a bit of it compared to what's been released over the years.  Note that tracking data show that some of these Transit satellites have broken up over the years.  It also shows the Transit 5-BN-1 and 5-BN-2 satellites in roughly 1,100 km near polar orbits.

As I understand it, there is currently a shortage of Plutonium 238 in the U.S., since this isotope hasn't been produced for many years.  The U.S. has bought the stuff from Russia in recent years, but now must restart production to provide enough for future NASA RTGs.  This "production line" will only create a few kg of the material.

I wonder how much it costs to restart production.  I wonder, at the same time, what it might cost to go into polar orbit, grab those Transit 5 SNAPs, and bring them back with their 2 or so kg of Plutonium 238.

 - Ed Kyle
« Last Edit: 05/28/2009 08:46 pm by edkyle99 »

Offline DMeader

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Re: What if the Apollo missions never left Earth orbit?
« Reply #53 on: 05/28/2009 10:09 pm »
There'd be enough fuel aboard a lunar CSM to do a retroburn, release the LM, and then to a posigrade burn to reestablish LEO for the CSM.

That might have been a little sporty!   ;)

Offline Kaputnik

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Re: What if the Apollo missions never left Earth orbit?
« Reply #54 on: 05/28/2009 11:46 pm »

I wonder how much it costs to restart production.  I wonder, at the same time, what it might cost to go into polar orbit, grab those Transit 5 SNAPs, and bring them back with their 2 or so kg of Plutonium 238.

 - Ed Kyle

Surely that 238 will be a bit tired by now? It'll be a lot 'cooler' than when it was manufactured.
Secondly, a mission to retrieve parts of a polar orbit satellite would undoubtedly cost billions- you'd need a new return capability as well as a robotic spacecraft disassembly ability.  I'd love to see it but I doubt it'll happen...
"I don't care what anything was DESIGNED to do, I care about what it CAN do"- Gene Kranz

Offline the_other_Doug

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Re: What if the Apollo missions never left Earth orbit?
« Reply #55 on: 05/29/2009 12:56 am »
I wonder how much it costs to restart production.  I wonder, at the same time, what it might cost to go into polar orbit, grab those Transit 5 SNAPs, and bring them back with their 2 or so kg of Plutonium 238.

As has been noted, the Pu238 in orbit, while still toxic, is rather depleted by now.  It might be useful to collect it from a garbage containment point of view, but I doubt anyone is likely to pay the cost any time soon.  (Launching anything into orbit, much less polar orbit, isn't going to be "cheap" for quite a while, obviously, though I suppose Pu238 production ain't cheap, either.)

However, I *have* heard something about a restart of production!  The current administration has apparently at least begun the discussion that can lead to a restart.  Apparently, from what I understand, the initiative has little to do with military uses and mostly to do with powering spacecraft.

And now, back to our historical topic...  :)

-the other Doug
-Doug  (With my shield, not yet upon it)

Offline kevin-rf

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Re: What if the Apollo missions never left Earth orbit?
« Reply #56 on: 05/29/2009 02:04 am »
As has been noted, the Pu238 in orbit, while still toxic, is rather depleted by now. 

Uuummm Pu238 has a half life of 87.5 years! In the 40 odd years it has been up, less than 1/4 of it has decayed. It is still hot and still radioactive as hell.
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Offline Blackstar

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Re: What if the Apollo missions never left Earth orbit?
« Reply #57 on: 05/29/2009 05:19 am »
1-This "production line" will only create a few kg of the material.

2-I wonder how much it costs to restart production. 

1-Approximately 5 kg per year after the production line is up and running in approximately 8 years.

2-Probably $150-$300 million.

Online Herb Schaltegger

Re: What if the Apollo missions never left Earth orbit?
« Reply #58 on: 05/29/2009 08:51 pm »
As has been noted, the Pu238 in orbit, while still toxic, is rather depleted by now. 

Uuummm Pu238 has a half life of 87.5 years! In the 40 odd years it has been up, less than 1/4 of it has decayed. It is still hot and still radioactive as hell.

Actually, my calculation for a 87.5 year half-life over 40 years leads to about 72.8% remaining.  But given the fact that 27% HAS decayed and thus diluted the remaining fraction with what is basically inert thermal mass, I would think that actual output of the radioactive material remaining in the RTG would be similarly reduced.  I would be interested in hearing from someone with a better handle on the RTG engineering involved.
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Offline the_other_Doug

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Re: What if the Apollo missions never left Earth orbit?
« Reply #59 on: 06/05/2009 12:53 am »
Found the document I was looking for -- it was announced about a month ago that Pu238 production will be resumed in the upcoming years:

http://www.msnbc.msn.com/id/30621668/

The baseline production plan seems to be limited to producing roughly 11 lbs of Pu238 per year, to be used solely by NASA spacecraft.  The production needs were apparently expressed to the Department of Energy by Mike Griffin before his departure as NASA Administrator.

The total cost of restarting production is pegged in this article as roughly $150 million, with about $30 million needed in the next fiscal year to do the engineering studies and prepare the paperwork.

-the other Doug
« Last Edit: 06/05/2009 12:55 am by the_other_Doug »
-Doug  (With my shield, not yet upon it)

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