Fwd: 45 Years Since the Unlucky Voyage of Apollo 13

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From: "Gary Johnson" <gjohnson144@comcast.net>
Date: April 15, 2015 at 9:53:15 PM CDT
To: "'Jack Knight'" <jack77062@sbcglobal.net>, "'Dave Whittle'" <dwwhittle@gmail.com>
Subject: RE: Fwd: 45 Years Since the Unlucky Voyage of Apollo 13

Jack thanks for the Great write up on the mission and your personal involvement. I copied my distribution list on bcc. We need to hear from Jack Garman and others.

Gary

 

From: Jack Knight [mailto:jack77062@sbcglobal.net]
Sent: Wednesday, April 15, 2015 6:48 PM
To: gjohnson144@comcast.net; Dave Whittle
Subject: Re: Fwd: 45 Years Since the Unlucky Voyage of Apollo 13

 

Personal view of Apollo 13- Jack Knight

 

We were very lucky on Apollo 13. The time the event happened made it possible to do what we did. Had it happened much later, especially after we were in lunar orbit, all may have been lost. Had it happened much earlier, it's not clear how it would have turned out due to consumables exhaustion.

 

Apollo 13 was the first Apollo manned Lunar mission which was not on a "free return" trajectory. It was also the first mission where the plan was for the LM flight controllers, and others, to not support during most of the transit time to the moon (boring, overtime costs, etc.). However, we were there for the scheduled entry of the crew into the LM during translunar coast since the crew would power up the LM momentarily and might have something to report.

 

I was not on shift when the event occurred. I had been off-shift and was playing softball in downtown Houston when the accident happened so the first I heard was from the radio while driving back home. When I got home I immediately called in and asked if it was serious or had the media exaggerated. I was told it was pretty serious so I came in. By then, of course, lots of other people were in and were being formed up into teams to address various options.

 

From where I sat, there was one key question - how long was it going to take to get back? That would determine whether the LM consumables would or could support. One of those consumables was extremely limited and virtually unmanageable (3 people had to breathe all the time!) and that was the LiOH. The others, O2, water, and battery power were either manageable (battery power if it didn't take too long) or we had plenty (water and O2).

 

I think that the trajectory guys pretty quickly had a worst case time-to-return number and a possibility to accelerate it by about 24 hours. I recall noting to my boss the issue with LiOH - namely that the LM and PLSS [round] cartridges alone would not support three people for the return time so some way had to be devised to make use of the CSM [square] cartridges.

 

I also had to consider that I had a shift coming up in a few hours and had not been to sleep. It was pretty apparent that the teams Gene Kranz had established to work specific problems did not need excess help and we still had to manage what was still working. So I went home for a few hours sleep and returned for my shift monitoring the LM.

 

The decision had been made to press on and fly around the moon and do the trajectory corrections with the LM prop system after coming around. The Flight Directors were adamant on keeping the LM GNC systems powered up so that we did not lose the attitude reference and state vector in the vehicle. That meant the LM GNC systems were kept powered up for that entire time, depleting LM battery power. The LM TELMU position was constantly re-calculating the power down situation based on the rate and time the higher power levels were being used. After the major burn was done, equipments were powered down and the LM power reduced to a total of about 300 watts. This kept the ECS, EPS and minimum communication systems alive. The MER and other people had solved the LiOH problem with a novel use of tape and paper and plastic wrap to allow the CSM cartridges to be used in the LM.

 

Other events I recall during the transearth coast:

 

- The LM trajectory was being perturbated slightly. But this was not figured out until much later - it turned out to be the LM water sublimator exhaust. It was small but over time it did make slight perturbations. The sublimator was supposed to the "thrust neutralized" but in this configuration it was not quite thrust neutral. There was nothing we could have really done about it, even if we had known.

 

- One of the LM descent batteries "exploded" (the words handed over to me when I came on shift - presumably due to gas buildup) towards the end of its life but fortunately did no obvious damage.

 

- The LM descent prop system had a liquid helium tank. It had a burst disk in case the pressure in the tank exceeded certain limits. Over time, the heat leak continued to raise the pressure and the burst disk let go. The LM GNC was warning it could happen so it was not a big surprise but the release of the gas spun up the vehicle and the crew had to re-establish the wobbly PTC rates.

 

- The lack of power meant that the crew areas got cold. The air being circulated was less than 40F, and it was being forced into the CSM, which was very cold. Ice was forming on the windows and other areas in the CSM. The CSM insulation design was based on it being powered and in a constant PTC state. The LM insulation was designed for lunar surface operations in constant sunlight and no rotation. So they were both operating outside design environments. I suggested that the crew consider getting in their space suits to get warmer but that was vetoed by the surgeons as they thought that if they got in those suits and began sweating then were re-exposed to the cold air, they would be worse off. Toward the end of the transearth coast, the CSM was being powered up and the LM margins had been increasing so we were asked to power some electronics up to add heat to the interior. We did and that helped, according to the crew.

 

- The LM ascent batteries were also used to recharge the CSM entry batteries as much as possible since that was the only power the CSM would have after LM separation. The small heater circuit used during translunar coast for the CSM to power certain LM heaters was used for this.

 

- After LM undock and separation, my technical job was essentially over, but like everyone else, I wanted to be there for the entry. The LM continued toward roughly the same entry corridor as the CM and pretty well burned up during entry, with parts landing in the Pacfic.

 

The period of time awating communications after the blackout period was one of the most tense I ever recall. The team had done everything it could and yet it could have come to naught if the heat shield had been damaged or the chutes didn't open. It was a little over a minute after we should have heard something before comm was established and a camera on the aircraft carrier locked in on the CM hanging on the chutes.

 

- Years later someone projected the original trajectory the stack was on when the incident happened. The projection indicated that the stack would have returned to the earh's vicinity and would have been captured. But it would have swung way out and come back and entered the atmosphere some days or weeks later (I've forgotten which).

Jack Knight

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From: "gjohnson144@comcast.net" <gjohnson144@comcast.net>
To: "Knight, Jack" <jack77062@sbcglobal.net>; Dave Whittle <dwwhittle@gmail.com>
Sent: Wednesday, April 15, 2015 4:50 PM
Subject: Fwd: 45 Years Since the Unlucky Voyage of Apollo 13

 

Jack and Dave you were both LM flight controllers, so I would like here about your involvement and thoughts on Apollo 13 that I can also share with others.

Gary

 

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From: gjohnson144@comcast.net
To: "Charles Mars" <cmars@cfl.rr.com>
Sent: Wednesday, April 15, 2015 4:47:24 PM
Subject: Re: 45 Years Since the Unlucky Voyage of Apollo 13

 

Charlie thanks very much for providing the involvement by you and KSC Launch Operations during Apollo 13. I am still looking for other engineers to respond. I copied the other on my distribution so they could see your note also (bcc). 
Take care,

Gary

 

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From: "Charlie Mars"
To: gjohnson144@comcast.net
Cc: "Jerry Johnson" , "Fred Haise"
Sent: Wednesday, April 15, 2015 7:17:02 AM
Subject: Re: Fwd: 45 Years Since the Unlucky Voyage of Apollo 13

 

Gary,  Got me thinking. I was head of the Lunar Module Project Engineering Office for Launch Operations at KSC. Lots of interface with the Houston bunch.  Especially Rip Bolander, Owen Morris, Dave Ballard and other names that will occur to me about 3 A. M. in the morningl  As we all know, everybody remembers incidents differently. This is how I remember what we did at KSC.  The Command Module batteries were a concern due to the extended deep freeze, as were a lot of other components.  I seem to remember the computer specs were violated such that some folks thought they would not power up??  Came up without a problem. Wish I could still do that

 

Anyway,  I had a team of Gruman, Rockwell and NASA engineers at KSC to figure out how to use the Lunar Module batteries and some rigged wiring to charge the Command Module batteries.  I know that Downey, Bethpage and the Houston bunch were all working that, as well as many other problems. All involved across the country fed information to Houston to be used as they deemed fit. We thought we had a good solution and fed the information to the decision makers.  Not sure of the procedure used, but I believe the procedure was carried out successfully and helped the reentry power situation.  Most folks only knew of the Houston part in bringing Apollo 13 home.  Thousands of man hours were spent across the country in support of that magnificent effort.

 

 

 

 

 

I know a lot of you on my list provided support to the Apollo 13 mission. I have often been asked what I did for engineering support from the MER. Attached is a short write up on my support in the MER during the mission and I would like to hear what your involvement was and I would share that with others.

Thanks,

Gary