Author Topic: ASTP SPS Abort To Orbit  (Read 6528 times)

Offline BigRIJoe

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ASTP SPS Abort To Orbit
« on: 06/14/2015 05:19 pm »
Lets say that an under performing S-4-B stage required the Apollo 18 service propulsion system burn to get into orbit. The docking module would be left behind on the S-4-B stage. What kind of alternative mission would have been flown?
« Last Edit: 06/14/2015 05:23 pm by BigRIJoe »

Offline Kaputnik

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Re: ASTP SPS Abort To Orbit
« Reply #1 on: 06/14/2015 08:07 pm »
I would imagine the resulting mission may have resembled Atlantis' first flight to Mir- or Gemini 6/7- perhaps with an opportunity for an artificial eclipse study?
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Offline DaveS

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Re: ASTP SPS Abort To Orbit
« Reply #2 on: 06/14/2015 08:13 pm »
I would imagine the resulting mission may have resembled Atlantis' first flight to Mir- or Gemini 6/7- perhaps with an opportunity for an artificial eclipse study?
Atlantis first flight to Mir was STS-71 which was the first Shuttle/Mir docking mission. Perhaps you're thinking of STS-63 where Discovery just performed a rendezvous with Mir. Discovery did not get to dock with Mir until STS-91.
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Offline the_other_Doug

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Re: ASTP SPS Abort To Orbit
« Reply #3 on: 06/15/2015 04:09 am »
Because the docking itself was such an important part of ASTP, the abort modes were changed slightly for it.

If the S-IVB underperformed or cut off fairly close to orbital insertion speed, the final abort mode was for the CSM to fire its plus-X RCS thrusters down to a given redline, while still attached to the S-IVB.  This was followed by an emergency separation, turnaround and docking with the DM, and then a quick boost into a safer, more permanent orbit.  As I recall, they would have attempted this had the first orbit been at least 60 miles in perigee, figuring they could get to the bail-out burn in time to save the mission.

The OP's concern was valid, though -- earlier S-IVB cutoff would have resulted in just the SPS abort he was speaking about, and the DM would have been lost to the mission.
-Doug  (With my shield, not yet upon it)

Offline BigRIJoe

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Re: ASTP SPS Abort To Orbit
« Reply #4 on: 06/15/2015 05:25 pm »
I should have been more specific, Doug. I was assuming that an SPS abort to orbit would involve S-4B shutdown and separation, RCS firing to insure no re-contact happened , and then an SPS burn to orbit. I'd love to see the specifics for this mode of RCS abort to orbit mode. Are they covered in the ASTP press kit..........anyone?

Offline DMeader

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Re: ASTP SPS Abort To Orbit
« Reply #5 on: 06/15/2015 05:43 pm »
I've never seen ASTP referred to as "Apollo 18".
« Last Edit: 06/15/2015 05:44 pm by DMeader »

Offline djellison

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Re: ASTP SPS Abort To Orbit
« Reply #6 on: 06/15/2015 05:57 pm »
If the S-IVB underperformed or cut off fairly close to orbital insertion speed,....

To be fair it's a pretty fringe case - it was the final 1.5 seconds of powered flight.

http://history.nasa.gov/astp/documents/Astp-recoveryreq.pdf  ( sec 2-2 )


Offline kch

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Re: ASTP SPS Abort To Orbit
« Reply #7 on: 06/15/2015 05:59 pm »

Offline the_other_Doug

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Re: ASTP SPS Abort To Orbit
« Reply #8 on: 06/15/2015 06:01 pm »
I should have been more specific, Doug. I was assuming that an SPS abort to orbit would involve S-4B shutdown and separation, RCS firing to insure no re-contact happened , and then an SPS burn to orbit. I'd love to see the specifics for this mode of RCS abort to orbit mode. Are they covered in the ASTP press kit..........anyone?

I'm as positive as I can be about anything that happened 40 years ago that I read this in Aviation Week in the two to three months before the mission.  Not sure if it's in the press kit.

Keep in mind that they still had the COI abort available (CSM Orbit Insertion, also called Command Orbit Insertion), and there was a threshold fairly late in the S-IVB burn where that abort mode came in.  But after that, this new RCS to orbit mode was added.  If they got enough speed and altitude for the RCS abort mode to work, they moved into that mode and, if the S-IVB shut down after that point, they tried to save the DM and the mission.

They didn't skip the COI abort mode just because of the DM, though.  If they had to get off the S-IVB for their own safety, and to ensure a safe re-entry, they would have done it in a heartbeat, I'm sure.
-Doug  (With my shield, not yet upon it)

Offline gwiz

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Re: ASTP SPS Abort To Orbit
« Reply #9 on: 06/16/2015 09:42 am »
I've never seen ASTP referred to as "Apollo 18".

http://history.nasa.gov/apollo/soyuz.html

:)
I've never seen a contemporary NASA source refer to ASTP as Apollo 18.  Apollo 18 was a cancelled lunar mission.

Offline deaville

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Re: ASTP SPS Abort To Orbit
« Reply #10 on: 06/16/2015 10:16 am »
I haven't looked for these but you may well find the answers to your question in 'Flight Plan Guidelines ASTP 40 300' and 'Contingency Plan ASTP 40 500'. I'm assuming that these documents are available to a diligent search on-line.
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Offline edkyle99

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Re: ASTP SPS Abort To Orbit
« Reply #11 on: 06/16/2015 02:05 pm »
I've never seen ASTP referred to as "Apollo 18".

http://history.nasa.gov/apollo/soyuz.html

:)
I've never seen a contemporary NASA source refer to ASTP as Apollo 18.  Apollo 18 was a cancelled lunar mission.
I don't recall anyone calling it Apollo 18 when it took place.  It was Apollo Soyuz Test Project, which was distinct from Project Apollo.  The official ASTP Press Kits (from both countries) are still easy to find.

Apollo 18 doesn't make sense anyway.  What about the three Apollo spacecraft that flew to Skylab?  What about SA-513?

 - Ed Kyle
« Last Edit: 06/16/2015 03:17 pm by edkyle99 »

Offline kevin-rf

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Re: ASTP SPS Abort To Orbit
« Reply #12 on: 06/16/2015 02:50 pm »
Would that be Apollo 23 then, since Apollo 22 would have been the backup Skylab rescue mission that never flew?
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Offline the_other_Doug

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Re: ASTP SPS Abort To Orbit
« Reply #13 on: 06/17/2015 03:06 am »
There was definitely a set of mixed signals sent by NASA PAO and NASA HQ in re the "Apollo 18" designation.  I do recall that, at the time, since the Soyuz was going to be numbered in the existing Soyuz flight numbering system (it was Soyuz 19, IIRC), NASA seemed to feel it needed to number the Apollo mission as well.  (Who knows, maybe it was the State Department that thought there should be "parity" in the spacecraft numbering scheme.)

I did hear the popular media at the time (read: CBS, NBC and ABC) refer to it as Apollo 18 several times prior to the flight, but called the mission ASTP.  I'm pretty sure it was also designated Apollo 18 in several articles in AW&ST in the year or so preceding the flight.

However, during the flight, the Russians used their standard procedure of having the commander select a call sign (I'm not sure if I have ever read what Leonov's was), and in English, calls to the Soyuz were just made to "Soyuz."  Similarly, calls to the Apollo were made to "Apollo," without a mission number.

So, everyone is sort of right.  CapCom never hailed the American spacecraft was "Apollo 18" or even just "Eighteen."  And the mission press documents once the mission was underway, including the press kit, referred to the American spacecraft as just Apollo and the Soviet just as Soyuz.  Apollo 18 was at one time the official designation of the flight, but doesn't seem to have been the official designation once the flight actually occurred.

The Soviets still maintained the designation Soyuz 19 within their own flight documentation, though.  Of course, they had to worry about what to number the next Soyuz flight, while NASA didn't have that worry with the final flight of an Apollo CSM.

Oh, and as for the CSMs that flew in Skylab, they held the designations Skylab 2, Skylab 3 and Skylab 4.  Not being part of mainline Apollo, and having been somewhat modified to remain in orbit for up to three months before returning their crews (which the ASTP CSM was not), they got a different mission designation and numbering entirely.
-Doug  (With my shield, not yet upon it)

Offline deaville

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Re: ASTP SPS Abort To Orbit
« Reply #14 on: 06/18/2015 12:46 pm »
Further to my previous post, there is on the NASA Technical Reports Server a document that lists contingency plans for an early or late lift-off and extra provision made to cater for this eventuality but nothing that I can find that deals specifically with an under performing Saturn stage.

This site also has on-board voice transccripts of the mission - NASA-TM-X-72912, JSC-09966 - that  make an entertaining read. As far as call signs are concerned Apollo was simply "Apollo" and Soyuz was simply "Soyuz".
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Offline BigRIJoe

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Re: ASTP SPS Abort To Orbit
« Reply #15 on: 06/18/2015 08:23 pm »
Also, in the official transcripts, there was no "Mode 5" call made to the spacecraft during ascent

Offline the_other_Doug

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Re: ASTP SPS Abort To Orbit
« Reply #16 on: 06/18/2015 10:58 pm »
Also, in the official transcripts, there was no "Mode 5" call made to the spacecraft during ascent

As Doug Ellison pointed out above (he's the original Doug, by the way, in relation to whom I'm the Other Doug -- goes back to days on sci.space usenet discussion boards, and thence onto his excellent unmannedspaceflight.com forum), it was such a short period at the end of an otherwise-nominal S-IVB burn during which Mode V would have been in effect that there would be no call-out until and unless there was an underspeed shutdown.  It's also not like the RCS abort-to-orbit had to be done within seconds of the condition being called out.  They had several minutes during which they could configure for the RCS burn.  A Mode IV needed you to power up the SPS gimbal motors and initialize the TVC logic (i.e., all the stuff you needed to do before burning the SPS engine), so the call-out for it was needful.  Also, the call-outs on the abort modes tended to let the crew know what abort procedure was now in effect, up until the time the next mode kicked in; since they were in Mode IV until seconds before shutdown, and since Mode V would not have required any staging, separation or main engine events, you just didn't need to worry about prepping for it.

I'm sure, too, that the crew trained to be prepared for a Mode IV right up to the end of the S-IVB burn, but to treat a potential Mode V as a special type of underspeed trim burn, rather than a full-on abort condition.
-Doug  (With my shield, not yet upon it)

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