What did NASA Change After the Apollo 13 Disaster?

NASA didn't have time to develop a new spacecraft after Apollo 13, but it did fix the old one. The near disaster (or successful failure) on Apollo 13 was chalked up to a bad combination of human error and poor design. To avoid a second translunar crippling explosion, the agency revisited the oxygen tank inside the service module before launching Apollo 14 to the Moon.


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[MaxHeadroom]

In addition to reworking the electronics, the tanks were placed on 3 different levels of shelving; top, middle, bottom.  They were also oriented at 120 degree intervals in the circular service module so that no two tanks were on top of each other.  Finally, a layer of Kevlar armor was placed on the sides, top and bottom of each assembly to prevent fragments of an exploded tank from damaging other components of the spacecraft.  Grandpa worked at North American and told me that one.

[johanneskristian]

I can't for the life of me understand why anyone would hit the 'thumb down' button on these videos. They're great, and Teitel is brilliant! As someone who's been a Apollo Programme nut since 5th grade(I'm 30 now, I'm old LOL) I love watching these. Thank you, Amy :-)

[C]

Excellent presentation. Just a couple of notes. When the shelf was dropped 2 inches in October 1968, the drain tube, which was difficult to tighten due to it's position became dislodged, preventing de-tanking after the CDDT ( countdown demonstration test). Heating the tank vented the O2 out the vent tube as well as causing the relay to be fused closed by the electrical overload.
Apollo 10 was the first apollo flight to experience a fuel cell failure. It occurred on the way home so it did not affect the mission. If it had occurred outbound to the moon, the mission would have be scrubbed.

Jack Swigert actually volunteered early to be a command module specialist as did Ken Mattingly. He was on the support crew for Apollo 7. Just prior to launch, Wally Schirra, who had a very perfectionistic and overbearing presence in the planning of the flight and manufacture of the CM did something that proved a great asset. He personally asked Jack Swigert to come up with an emergency power down checklist just in case there was an explosion in the service module.
God moves in mysterious ways.

[Funkestech]

I'm just glad it wasn't Kevin Bacon's fault. Such a nice bloke.

[mcsseattle]

Very fortunate that the Apollo 13 defect was not on the Apollo 8 command module since they did not have the lunar module life boat.

[Sutterjack]

Great seeing someone so young with such a passion for space history - I enjoy your channel

[jconradh]

Watching this video again. Thank you, Amy, for the very complete information given concisely and well presented. I have found many narrators speak so slowly I have to watch their videos at 1.5 to 2X speed. Hope you're doing well. I finaly have copies of all your books!

[miked]

Yesterday I toured Johnson space center in Houston and toured the historic mission control room. While I was disappointed that the room was incomplete at this time I was thrilled to be in such a historic place and cannot wait until next summer when restoration is complete in honor of the 50th anniversary of Apollo 11 landing on the moon!

[rhom]

Jim Lovell's biography "Lost Moon" outlines a slightly different sequence of design and procedural failures leading up to the infamous O2 tank explosion (my apologies for the wordy explanation):

(1) The O2 tank heaters were originally specified to operate on 28V power; NASA asked their contractors to change their electrical systems to 60V (which was used on the launch pad systems). Beech Aircraft complied on the heater, but the heater relay was overlooked and designed for 28V (first design mistake). The electrical heaters were only to be used during ground tests to thaw out the O2 tank after draining (to prevent condensation of moisture in the air). A dip tube allow the tank to emptied out through the top of the tank.
(2) Test procedures dictated no higher than 80 Degree C inside of the O2 tank whenever the heater was active and there was a thermocouple installed inside to measure temperature. Unfortunately, this temperature sensor was connected to a dial readout which topped out at 80 Degree C (second design mistake).
(3) When the tank was accidentally dropped, as mentioned in Amy Shira Teite's videol, the dip tube broke off but nobody knew of this damage (not sure if X-Raying the tank would have picked up the problem).
(4) Two weeks before the launch, a full pad test was conducted with both H2 and O2 tanks in the Service Module fully loaded with their cryogenics. At the end of the test, engineers discovered they could not fully empty one of the O2 tanks (which in the post-flight investigation was attribute to the broken dip tube). In an early morning meeting with the astronauts, engineers and managers, was decided to boil-off the liquid O2 using the tank heater. As a safety measure, an engineer was assigned to monitor the tank temperature during the boil-off.
(5) When the heater was turned on, the 28V relay contacted fused shut on the 60V heater power, thereby letting the temperature to reach 1000 Degrees C. The test engineer only saw the needle on the undersized air reaching 80 Degree C. The kiln-like temperature boiled off all of the liquid O2, but also frayed all of the teflon insulation around the heater elements and cryo stir fan motors, exposing bare electrical wires.
(6) During the flight, two O2 tank cryo stirs were done without incident. On the third cryo stir, sparks jumped between the bare fan motor wires and the tank wall which ignited the teflon debris; in the pure liquid O2 environment, the insulation exploded like a bomb.

No one design or procedural mistake would have been fatal, but the combination resulted in a catastrophic explosion. Fortunately, the failure occurred at a point in the mission where it was survivable.

[blueskies]

From Jim Lovells’ book. Before launch In a meeting they described the venting problem to him. They discussed the work around they came up with. But offered to Jim to delay the launch and change out the shelf and tank. Of course no one could fully understood the consequences at the time and they all agreed to press on.

[scottlawton]

Human error and flawed design = 100% human error

[WizzRacing]

I believe the issue was the ground crew had not got the updated schematics of the valve. As NASA changed the voltage from 85 to 28 volts. So when they tested the tanks at the factory they used the 85 volts and the contacts welded shut and burn the wiring to where it was exposed. When they refilled the tank after the test fight prep they used the voltage to bleed off what remained.

It's a damn miracle they made it back. As that tank was in the outside position in the rack and it blew the panel cover off without destroying the CSM inside. They also had extra oxygen for the longer lunar mission duration onboard. They also shut down the CM with only 2 mins left before the AGC went down for good. Just few of the 40 they had to have go right.

[alaingloster]

That is the coolest Apollo visual aid I've ever seen :)

[computername]

My mum took me to this movie in the afternoon after school, when I was ten years old.
20 years later I am an engineer and develop technology every day, with pride and joy.
I would like to thank NASA, Science, everybody who contributed to it and the makers of this movie for the inspiration of a lifetime. And my mum, for her incredibly cheeky way to get her boy motivated for a STEM career - in one afternoon. Not to mention the sentence "I can add".. with a proud smile.. kept me motivated for all the math learning.

Great show, as always. Apollo never gets boring..

[ericbryce]

Apollo 14 had it share of problems. The command module had trouble docking with the lunar module. After separation in lunar orbit a false reading threatened to auto abort the landing until a program was written by M.I.T. to instruct the LM computer to ignore the auto abort command. During the main lunar excursion the small cart used would not roll in the dust and had to be carried.  During that excursion the crew became disorientated and failed to reach their ultimate goal the rim of Cone crater. Some said they failed because Shepard and Mitchell were less than fully dedicated to pre-mission training.

[bhurley]

Your best segment! Love the model used and the technical details/pictures!

[garfieldsmith]

It was not a disaster. It was a victory. Using pencils, paper, slide rules, and a lot of determination NASA brought the crew back home safely. I had the honour of hearing Gene Kranz speak about the mission many years ago when our company invited him to tell the story about how the team work saved the lives of the astronauts. It was a tremendous endeavour and the NASA team is to be commended for their actions.

[mavericktheace]

"Sink or..." Sink or what?! I need to know! this could be important someday.

[jefferydavis]

They also changed filters so that the Command Module and the LM filters were the same

[kerneldbg]

My father was a Bellcom engineer and specialized in pressure vessels. He was part of the Apollo 13 investigation and told me exactly what you said. Nice job. 🙂