Author Topic: Apollo 8  (Read 59933 times)

Online catdlr

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Re: Apollo 8
« Reply #60 on: 11/08/2015 03:33 am »
Apollo 8 - Final TV (Full Mission 38)

Published on Nov 7, 2015
Apollo 8 - Final TV (Full Mission 38)

This video covers the 124-129 hour point in the mission, specifically PTC is re-initiated but not entirely sucessfull and the crew give the last TV broadcast from just under 100,000 miles out.

I have added in some pre flight photography.

Audio is presented in two channels at some points. Headphones are advised.

The video is presented in 16:9 to allow use of photos and captions on the right of the screen. Captions are used to show PAO and other events.

NOTE -

Orbiter Space Simulator is used to depict events as they were happening in real time, although I do not claim attitudes/spacecraft orientation are correct.

I sourced the Apollo 8 Flight Journal to assist with photo placement and audio editing. I would recommend the viewer using this as an aid whilst listening as it gives great descriptions of the technical details of the flight as it happened and explains, in laymans terms what is going on.

All video, photos and audio is courtesy of NASA.



Tony De La Rosa, ...I'm no Feline Dealer!! I move mountains.  but I'm better known for "I think it's highly sexual." Japanese to English Translation.

Online catdlr

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Re: Apollo 8
« Reply #61 on: 11/12/2015 11:28 pm »
Onboard Apollo 8 - Genesis

Published on Nov 12, 2015
This is a short video to supplement the Apollo 8 Full Mission series using the audio from the onboard tapes played with the TV broadcast from lunar orbit on 24th December 1968.

The audio starts about 10 minutes before the Genesis reading and the crew can be heard discussing the various lunar features they are seeing before broadcasting their comments to the TV audience on Earth.

The sequence ends with the infamous reading from Genesis and concludes with crew comments about the broadcast as they were worried that the message had not been broadcast.

Tony De La Rosa, ...I'm no Feline Dealer!! I move mountains.  but I'm better known for "I think it's highly sexual." Japanese to English Translation.

Online catdlr

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Re: Apollo 8
« Reply #62 on: 11/14/2015 11:04 pm »
Apollo 8 - Final Reentry PAD (Full Mission 39)

Published on Nov 14, 2015
Apollo 8 - Final Reentry PAD (Full Mission 39)

This video covers the 129-132 hour point in the mission, specifically a JSC briefing and the reading up of an updated reentry PAD along with prep for MCC7.

NOTE - there is missing audio from this sequence - specifically between GET 130:13 and 130:56.

Audio is presented in two channels at some points. Headphones are advised.

The video is presented in 16:9 to allow use of photos and captions on the right of the screen. Captions are used to show PAO and other events.

NOTE -

Orbiter Space Simulator is used to depict events as they were happening in real time, although I do not claim attitudes/spacecraft orientation are correct.

I sourced the Apollo 8 Flight Journal to assist with photo placement and audio editing. I would recommend the viewer using this as an aid whilst listening as it gives great descriptions of the technical details of the flight as it happened and explains, in laymans terms what is going on.

All video, photos and audio is courtesy of NASA.

Tony De La Rosa, ...I'm no Feline Dealer!! I move mountains.  but I'm better known for "I think it's highly sexual." Japanese to English Translation.

Online catdlr

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Re: Apollo 8
« Reply #63 on: 11/22/2015 09:09 am »
Apollo 8 - No MCC-7 (Full Mission 40)

Published on Nov 22, 2015
Apollo 8 - No MCC-7 (Full Mission 40)

This video covers the132-141 hour point in the mission, specifically the cancellation of Mid Course Correction 7 and a final press conference from JSC.

NOTE - there is some missing audio from this sequence which is noted on the screen.

Audio is presented in two channels at some points. Headphones are advised.

The video is presented in 16:9 to allow use of photos and captions on the right of the screen. Captions are used to show PAO and other events.

NOTE -

Orbiter Space Simulator is used to depict events as they were happening in real time, although I do not claim attitudes/spacecraft orientation are correct.

I have added some pre flight and launch photos into the video. These are the final photographs from the mission for this series.

I sourced the Apollo 8 Flight Journal to assist with photo placement and audio editing. I would recommend the viewer using this as an aid whilst listening as it gives great descriptions of the technical details of the flight as it happened and explains, in laymans terms what is going on.

All video, photos and audio is courtesy of NASA.


Tony De La Rosa, ...I'm no Feline Dealer!! I move mountains.  but I'm better known for "I think it's highly sexual." Japanese to English Translation.

Online catdlr

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Re: Apollo 8
« Reply #64 on: 11/22/2015 05:37 pm »
Apollo 8 - Go For Re-Entry (Full Mission 41)

Published on Nov 22, 2015
Apollo 8 - Go For Re-Entry (Full Mission 41)

This video covers the141-145 hour point in the mission, specifically the crew getting ready for re-entry, checking the Service Module pyro arm switch was ready to jettison the SM and testing VHF communications. The vide ends just before SM jettison.

Audio is presented in two channels at some points. Headphones are advised.

The video is presented in 16:9 to allow use of photos and captions on the right of the screen. Captions are used to show PAO and other events.

NOTE -

Orbiter Space Simulator is used to depict events as they were happening in real time, although I do not claim attitudes/spacecraft orientation are correct.

I sourced the Apollo 8 Flight Journal to assist with photo placement and audio editing. I would recommend the viewer using this as an aid whilst listening as it gives great descriptions of the technical details of the flight as it happened and explains, in laymans terms what is going on.

All video, photos and audio is courtesy of NASA.

Tony De La Rosa, ...I'm no Feline Dealer!! I move mountains.  but I'm better known for "I think it's highly sexual." Japanese to English Translation.

Online catdlr

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Re: Apollo 8
« Reply #65 on: 12/19/2015 10:28 pm »
EARTHRISE: The First Lunar Voyage

Published on Dec 19, 2015
See this amazing movie. EARTHRISE: THE FIRST LUNAR VOYAGE recounts the flight many consider to be NASA's most daring and important. Interviews with Apollo 8 astronauts, their wives, mission control staff, and journalists take viewers inside the high-stakes space race of the late 1960s to reveal how a bold decision by NASA administrators put a struggling Apollo program back on track and allowed America to reach the moon before the Soviets.

Preview and full documentary video links:



Tony De La Rosa, ...I'm no Feline Dealer!! I move mountains.  but I'm better known for "I think it's highly sexual." Japanese to English Translation.

Online catdlr

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Re: Apollo 8
« Reply #66 on: 12/28/2015 07:45 am »
Apollo 8 - Splashdown (Full Mission 42)

Published on Dec 27, 2015
Apollo 8 - Splashdown (Full Mission 42)

This video covers the145 hr to recovery point in the mission, specifically the SM jettison, re-entry , splashdown and final recovery to the Aircraft Carrier Yorktown.

This is the final video in the series. I would like to thank all those who have supported and given guidence through the past year, including Jim Lovell who continues to give encouragement and all the viewers on Youtube.

Audio is presented in two channels at some points. Headphones are advised.

The video is presented in 16:9 to allow use of photos and captions on the right of the screen. Captions are used to show PAO and other events.

NOTE -

Orbiter Space Simulator is used to depict events as they were happening in real time, although I do not claim attitudes/spacecraft orientation are correct.

I sourced the Apollo 8 Flight Journal to assist with photo placement and audio editing. I would recommend the viewer using this as an aid whilst listening as it gives great descriptions of the technical details of the flight as it happened and explains, in laymans terms what is going on.

All video, photos and audio is courtesy of NASA.

Tony De La Rosa, ...I'm no Feline Dealer!! I move mountains.  but I'm better known for "I think it's highly sexual." Japanese to English Translation.

Online catdlr

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Re: Apollo 8
« Reply #67 on: 10/18/2016 02:36 pm »
The Daring Adventure of Apollo 8 in 1968

 
Dan Beaumont Space Museum

Published on Oct 17, 2016



Tony De La Rosa, ...I'm no Feline Dealer!! I move mountains.  but I'm better known for "I think it's highly sexual." Japanese to English Translation.

Offline Blackstar

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Re: Apollo 8
« Reply #68 on: 10/18/2016 04:08 pm »

Online catdlr

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Re: Apollo 8
« Reply #69 on: 06/24/2017 12:50 am »
Apollo 8 Launch - USA Radio

lunarmodule5
Published on Jun 23, 2017

The Apollo 8 Launch with audio from USA Radio broadcast live.



Tony De La Rosa, ...I'm no Feline Dealer!! I move mountains.  but I'm better known for "I think it's highly sexual." Japanese to English Translation.

Offline 4throck

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Re: Apollo 8
« Reply #70 on: 12/13/2017 03:35 pm »
My take on the Apollo 8 TV transmissions.

Tried to correct several things:

- wide angle fish-eye lens distortion
- poor contrast and unnatural mid-tone balance
- convert the original 10fps images to 24fps by frame blending instead of simple duplication
- rotate the images to make orientation consistent

I think it's the first time that this correction was attempted, correct me if I'm wrong.
There's some minimal cropping on the fish-eye corrected images, but nothing serious. The edges are always very fuzzy so nothing is lost.

The result is not spectacular, but I think that it looks more natural this way. And easier to understand what you are looking at inside the Apollo capsule.










« Last Edit: 12/13/2017 03:39 pm by 4throck »

Offline Steve G

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Re: Apollo 8
« Reply #71 on: 04/23/2018 04:45 pm »
The original Apollo 8 mission, the E mission profile, would have flown as Apollo 9. As it flew as Apollo 8 as a C prime mission without a lunar module, then I assume LM4 went to Apollo 10, LM 5 to Apollo 11. Somewhere, there should have been a spare LM. When Apollo 15 H mission was cancelled, the CSM CSM-111, flew on the ASTP. The LM LM-9 is a museum piece at KSC. Since Apollo 8 should have had a LM associated for it, I assume somewhere in 1968-69 a LM order was cancelled. Does anyone know if and when NASA cancelled a LM order?

Offline Jim

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Re: Apollo 8
« Reply #72 on: 04/23/2018 05:31 pm »
The original Apollo 8 mission, the E mission profile, would have flown as Apollo 9. As it flew as Apollo 8 as a C prime mission without a lunar module, then I assume LM4 went to Apollo 10, LM 5 to Apollo 11. Somewhere, there should have been a spare LM. When Apollo 15 H mission was cancelled, the CSM CSM-111, flew on the ASTP. The LM LM-9 is a museum piece at KSC. Since Apollo 8 should have had a LM associated for it, I assume somewhere in 1968-69 a LM order was cancelled. Does anyone know if and when NASA cancelled a LM order?

They all skipped to the next mission.  If Apollo 8 had a LM, it would have been LM-3.  We don't know what would have happened to LM-8 & 9, if Apollo 8 had LM-3

LM-2 is at NASM, but it was never going to fly manned.




Offline the_other_Doug

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Re: Apollo 8
« Reply #73 on: 04/24/2018 01:45 am »
The original Apollo 8 mission, the E mission profile, would have flown as Apollo 9. As it flew as Apollo 8 as a C prime mission without a lunar module, then I assume LM4 went to Apollo 10, LM 5 to Apollo 11. Somewhere, there should have been a spare LM. When Apollo 15 H mission was cancelled, the CSM CSM-111, flew on the ASTP. The LM LM-9 is a museum piece at KSC. Since Apollo 8 should have had a LM associated for it, I assume somewhere in 1968-69 a LM order was cancelled. Does anyone know if and when NASA cancelled a LM order?

They all skipped to the next mission.  If Apollo 8 had a LM, it would have been LM-3.  We don't know what would have happened to LM-8 & 9, if Apollo 8 had LM-3

LM-2 is at NASM, but it was never going to fly manned.

Well... yeah, LM-2 never would have flown manned.  But there was some talk of it, in mid-1968.

First LM-1 and LM-2 were each supposed to be unmanned test vehicles.  Sometime in late 1967, ASPO asked Grumman if, assuming the test flight of LM-1 was successful and LM-2 could be released from repeating the B mission, what it would take to make LM-2 capable of supporting an early manned test flight.

It turned out that it would be easier, cheaper, and end you up with a better vehicle, to just proceed on with LM-4 and onwards and retire LM-2 from the flight line for good.  But, when Mike Collins (in Carrying the Fire) discussed the planning for the original sequence of the D and E missions during the late summer of 1968 (as he recovered from his surgery), he commented that the original D mission, Apollo 8, was being pushed to early spring of 1969 at the earliest, due to LM-3 running late with persistent leaks in its plumbing and breakage in its fragile wiring harnesses.  He then mentioned something along the lines of "And Borman's LM was in even worse shape, and was overweight to boot."

It sure sounds like, as of August 1968, Collins is describing LM-2 as "Borman's LM" and not LM-4.

Flying the D and E missions as planned would not have resulted in an earlier lunar landing, I don't think.  LM-3 wasn't going to be ready to fly until late February to early March, 1969, "even," as one manager told Rocco Petrone, "if you gave it to God."

So, if you just wait from Apollo 7 in October '68 to Apollo 8 (McDivitt's crew) in early March of 1969, flying LM-3, then Borman's crew, flying the E mission on Apollo 9, would fly out to a 4,000-mile apogee and test out LM-4.  The earliest LM-4 would have been ready was around May of 1969.

Apollo 10 would then fly with LM-5 in July of 1969, when it was ready.  If the D and E missions had been flown as planned, this would have been the very first flight of humans to the Moon.  Even though LM-5 was light enough to land, I seriously doubt the first landing would have occurred on the first flight out to the Moon.

That would have left the first landing to Apollo 11, flying LM-6, in September of 1969, when it would be ready.  Commanded by the very memorable first man on the Moon -- Pete Conrad.  Who, as backup to McDivitt's Apollo 8, would rotate to command Apollo 11.

In this scenario, it's more likely the E mission would have been extended to a lunar orbital flight, and may even have been canceled as such (i.e., no E mission at all), and Borman's crew would have basically flown the F mission.  Which would have resulted in Apollo 10 landing in July.

But in any event, if the D and E missions were flown as planned, LM-2 still ends up in the Smithsonian, and LM-6 would accomplish the first landing on Apollo 11, on 9/18/69, with Pete Conrad commanding.  If the E mission had been skipped and Borman's crew had flown the F mission, then the landing would have been accomplished on Apollo 10 by LM-5, on 7/20/69, with Tom Stafford commanding.

There was no set of goals in the Grumman LM contract that stated "OK, we will procure a vehicle per each lettered mission."  They just set up a production line and had an order for 12 LMs, with contract language allowing NASA to order additional vehicles.  The LMs were modified for their individual missions, as well as undergoing major modifications for the J mission lifetime extension enhancements, but there wasn't a "Oh, we needed to build an extra LM if we flew the E mission" moment.

Had the E mission flown and Apollo 11 failed to land in September, Apollo 12 would have a chance to try it, with Armstrong and Aldrin, in November.  And if they hadn't managed it, I imagine there would have been a push to launch Apollo 13 in December to try and beat the end-of-1969 deadline.  The Grumman assembly line was going full blast by this time; LMs 7, 8 and (if need be) 9 would have been ready for flight to support those attempts.
« Last Edit: 04/24/2018 01:57 am by the_other_Doug »
-Doug  (With my shield, not yet upon it)

Offline WallE

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Re: Apollo 8
« Reply #74 on: 04/24/2018 02:11 pm »
As is well-known, Apollo 8 was originally supposed to be a HEO test of the combined command and lunar modules, but this was dropped as being unnecessary, and then quickly converted to a solo CSM flight to lunar orbit.

This was a pretty big gamble to go to the Moon with just the CSM, because even well before Apollo 13, NASA were conscious of the need to have the LM along as a backup spacecraft if the CSM malfunctioned. One of the big reasons for the flight was worry about what the Soviet space program might be doing and how many manned circumlunar missions they might have up their sleeve. Nobody knew of course just how behind and totally disorganized the Soviet manned program was in 1968, and even the Soviets themselves were surprised that we'd attempt Apollo 8 without a prior unmanned test flight. Frank Borman states in his memoirs that the decision for a solo CSM lunar mission was not made until August 1968.

That also doesn't include the fact that the Saturn V was being committed to a manned flight after just two tests, one of which had some rather serious problems, or that the Apollo CSM itself was only on its second manned flight and was still something of a question mark. In regards to the second point, the hardware on Apollo 7 had performed almost flawlessly--the SPS and RCS systems were given an extensive workout and passed these tests with flying colors (in fact the crew were the only part of Apollo 7 that left something to be desired). This gave NASA sufficient confidence that the CSM was man-rated and could be trusted for Apollo 8's mission. If there had been problems on 7, then 8 would have flown another Earth orbital CSM test.

The SPS was considered pretty much failsafe anyway; in the entire Apollo program, only two SPS malfunctions occurred--on AS-201, the very first test of an Apollo CSM, and on Apollo 16, and neither was serious enough to prevent the main mission goals from being achieved.

Offline the_other_Doug

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Re: Apollo 8
« Reply #75 on: 04/24/2018 02:48 pm »
As is well-known, Apollo 8 was originally supposed to be a HEO test of the combined command and lunar modules, but this was dropped as being unnecessary, and then quickly converted to a solo CSM flight to lunar orbit.

This was a pretty big gamble to go to the Moon with just the CSM, because even well before Apollo 13, NASA were conscious of the need to have the LM along as a backup spacecraft if the CSM malfunctioned. One of the big reasons for the flight was worry about what the Soviet space program might be doing and how many manned circumlunar missions they might have up their sleeve. Nobody knew of course just how behind and totally disorganized the Soviet manned program was in 1968, and even the Soviets themselves were surprised that we'd attempt Apollo 8 without a prior unmanned test flight. Frank Borman states in his memoirs that the decision for a solo CSM lunar mission was not made until August 1968.

That also doesn't include the fact that the Saturn V was being committed to a manned flight after just two tests, one of which had some rather serious problems, or that the Apollo CSM itself was only on its second manned flight and was still something of a question mark. In regards to the second point, the hardware on Apollo 7 had performed almost flawlessly--the SPS and RCS systems were given an extensive workout and passed these tests with flying colors (in fact the crew were the only part of Apollo 7 that left something to be desired). This gave NASA sufficient confidence that the CSM was man-rated and could be trusted for Apollo 8's mission. If there had been problems on 7, then 8 would have flown another Earth orbital CSM test.

The SPS was considered pretty much failsafe anyway; in the entire Apollo program, only two SPS malfunctions occurred--on AS-201, the very first test of an Apollo CSM, and on Apollo 16, and neither was serious enough to prevent the main mission goals from being achieved.

One thing the official histories don't mention is that George Low, in proposing C' for the second manned Apollo mission, was violating one of the early primary mission rules, as you've pointed out -- prior to C' planning, you were NO-GO for LOI if you could not dock with and extract the LM during TD&E.  Without the LM's DPS available to correct the kinds of trajectories you could end up in if the SPS failed partway through LOI, you introduced some particularly ghastly LOC options where the CSM went off into solar orbit, or an eternal HEO.

Also, I will point out that AS-201 had the only major in-flight issues with the SPS itself, during which it failed to develop full thrust (due to helium ingestion issues, IIRC).  There were problems with the supporting electronics for the SPS on both Apollos 15 and 16, actually, but in neither case did the malfunctions render the engine unusable.

On Apollo 15, a diode in the direct thrust switching system -- a way to turn the engine on and off directly by simply opening the ball valves that fed propellants to the engine without invoking the computer control circuits -- failed such that, when one of the two redundant valve banks was armed, the engine would fire.  (IIRC, the "bad" bank of valves was Bank B.)  This had a simple work-around that let the crew follow nearly normal procedures -- they simply didn't arm that bank of valves for two-bank burns, like LOI and TEI, until after the computer initiated SPS ignition automatically.  They then disarmed it prior to commanded shut-off.  All other burns, such as lunar orbit shaping burns and mid-course corrections, were normally done as single-bank burns, so the "good" bank was simply selected for them.

Apollo 16, of course, had an issue with the thrust vector control (TVC) engine gimballing system.  The SPS was a gimballed engine, which would point the thrust vector (hence the name) through the center of gravity of the spacecraft.  The primary TVC control circuits worked fine on 16 but, after operating just fine through LOI and DOI, the secondary TVC control circuits induced a sharp shaking, or "nodding", motion in the engine bell.  It was only when data indicated that the engine was simply nodding around the desired vector, and would point the engine properly (though it would shake the crew pretty good), that the mission was allowed to proceed after the problem was first seen.

The really interesting thing about the Apollo 16 issue is that, as Ken Mattingly realized during flight and the investigation teams realized only after the mission was over, the only real likely failure mode that would cause the symptoms they saw would have been a connector in the line that ran from the CM computers and electronics down to the gimbal motors coming partially disconnected.  Mattingly knew those connectors and had the pin maps memorized -- the only way for the observed symptoms to appear, he was certain, was if one side of that connector had pulled apart and gapped the pins on one side.

Of course, you couldn't recover the service modules, so there was no way to tell for certain, but if the SM wiring harness that led to the gimbal motors was either misrouted or made a tiny bit too short, engine movement to one edge of the gimbal envelope could have pulled on that connector, and pulled it partially apart.  The thing that Ken knew, but the ground troops didn't really get until later, was that both the primary and secondary TVC control inputs came through the same cable.  Had the connector come completely unplugged (and hey, it had already been pulled partially apart, by event unknown) there would have been *no* thrust vector gimbal control at all on that engine.  Which led to Ken telling ASPO manager Jim McDivitt, after the flight, that considering the layout of the control wiring, he was really surprised that Houston had let the mission continue.  To which McDivitt responded "At the time, you were the only one who really understood where the problem had to be located.  Had we realized it, you're right -- we wouldn't have let you land!"
« Last Edit: 04/24/2018 02:54 pm by the_other_Doug »
-Doug  (With my shield, not yet upon it)

Offline WallE

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Re: Apollo 8
« Reply #76 on: 04/25/2018 10:18 am »
Also, I will point out that AS-201 had the only major in-flight issues with the SPS itself, during which it failed to develop full thrust (due to helium ingestion issues, IIRC.

But that was the first flight of a CSM, so that was ok. Any maiden flight of a new vehicle is going to have a few problems, it's more surprising if it doesn't.

The helium ingestion was due to a broken piece of plumbing that allowed helium to enter the oxidizer line and cause a 30% drop in engine performance 80 seconds into the SPS burn. A second burn, lasting 10 seconds, resulted in unstable combustion, dropping to as low as 12%. Lucky this was a pressure-fed engine because on a turbopump engine, helium entering the fuel system would cause pump cavitation and end pretty badly.

Offline the_other_Doug

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Re: Apollo 8
« Reply #77 on: 04/25/2018 03:55 pm »
Also, I will point out that AS-201 had the only major in-flight issues with the SPS itself, during which it failed to develop full thrust (due to helium ingestion issues, IIRC.

But that was the first flight of a CSM, so that was ok. Any maiden flight of a new vehicle is going to have a few problems, it's more surprising if it doesn't.

The helium ingestion was due to a broken piece of plumbing that allowed helium to enter the oxidizer line and cause a 30% drop in engine performance 80 seconds into the SPS burn. A second burn, lasting 10 seconds, resulted in unstable combustion, dropping to as low as 12%. Lucky this was a pressure-fed engine because on a turbopump engine, helium entering the fuel system would cause pump cavitation and end pretty badly.

Yep, that's one reason why pressure-fed engines were chosen for the major Apollo spacecraft engine systems.  Turbopumps can fail, and often have Bad Day results when they do.  Like, you thought Apollo 13's SM looked ripped up?  You ain't seen nuthin'... :(

That plus boil-off concerns was also one of the reasons why repeated suggestions, when looking at the Apollo mission mode, to use pump-fed hydrolox engines for LOI, descent and TEI were ignored.  Hydrolox for those maneuvers would have made a Direct Ascent mode semi-feasible, even with just a Saturn V launcher.  But it contained too many catastrophic failure modes (especially turbopump failure modes) for comfort, and hydrogen boil-off over the week or more it would have been happening was, and remains, beyond engineering capabilities.

Once someone actually demonstrates maintaining LH2 in-flight with acceptable boil-off rates, I'll happily amend that last statement.  But as of now, no LH2 stage has ever had a loiter time of more than about, what, six hours?  Apollo Direct Ascent with hydrolox LOI, landing and TEI stages would have required low boil-off rates for from three to seven days, which has not yet been achieved, I don't believe.  Not even within a couple of orders of magnitude...
-Doug  (With my shield, not yet upon it)

Offline WallE

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Re: Apollo 8
« Reply #78 on: 04/25/2018 05:37 pm »
Yep, that's one reason why pressure-fed engines were chosen for the major Apollo spacecraft engine systems.  Turbopumps can fail, and often have Bad Day results when they do.  Like, you thought Apollo 13's SM looked ripped up?  You ain't seen nuthin'

There were plenty of Atlas and Thor flights that demonstrated the evil things that can happen when a turbopump malfunctions.

That plus boil-off concerns was also one of the reasons why repeated suggestions, when looking at the Apollo mission mode, to use pump-fed hydrolox engines for LOI, descent and TEI were ignored.  Hydrolox for those maneuvers would have made a Direct Ascent mode semi-feasible, even with just a Saturn V launcher.  But it contained too many catastrophic failure modes (especially turbopump failure modes) for comfort, and hydrogen boil-off over the week or more it would have been happening was, and remains, beyond engineering capabilities.

I'm not sure who thought equipping the CSM with an LH2 engine was a good idea, but anyone with even so much as a rudimentary knowledge of how rocket engines work wouldn't be able to take the idea seriously. Putting reliability aside, turbopumps also increase the weight of the engine and weight limits on the Apollo missions were tight.

Aide from that, cryo engines need an igniter mechanism which adds yet more weight, complexity, and failure points.
« Last Edit: 05/05/2018 01:44 am by WallE »

Offline hygoex

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Re: Apollo 8
« Reply #79 on: 04/29/2018 09:21 pm »
Has there been any formal celebration planned for the Cape in December for the 50th anniversary?  Wanting to take my cousin's grandkids there then.

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