Anonymous
Anonymous asked in Science & MathematicsAstronomy & Space · 1 month ago

How was the LEM used as a lifeboat on Apollo 13?

The LEM engines should not be powerful enough to propell the Command and Service modules - that was the Service Module's job.  Nor was it designed to sustain three people for four days.  How did the astronauts ride the LEM all the way home?

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  • 1 month ago

    This sounds sarcastic but but im being serious, watch the movie... they simplified things for brevity but they actually explained everything pretty well.

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  • Anonymous
    1 month ago

    Multiple stories on this.  Have you heard of Google?

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  • 1 month ago

    One lunar module functioned as a lifeboat for the crew of Apollo 13, providing life support and propulsion when their CSM was disabled by an oxygen tank explosion en route to the Moon, forcing the crew to abandon plans for landing.

    Source(s): Google.
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  • 1 month ago

    You clearly don't grasp how space travel works.

    At the time of the accident, the spacecraft was on course to the Moon. It only needed a relatively small course correction to put the craft back on a free return trajectory so that it would return to the Earth after rounding the Moon. The LM Descent Engine was more than sufficient to that job.

    Indeed, the LM's supplies were not entirely sufficient, which is why the crew had to build an adapter so as to use the CM's lithium hydroxide canisters in addition to the differently sized LM canisters.

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  • D g
    Lv 7
    1 month ago

    Watch the movie the LEM attached to the command module just after launch when the accident occured they lost power in the command module to last the flight do the men moved to the LEM while it was attached to the Command module and the oxygen and power kgpt them slice there as it was not damaged  the command module was not using engines 

    After it leaves orbit a space craft does not need engines 

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  • 1 month ago

    After aborting their Lunar Orbit they still had their Momentum

     They Maximised the LEM's engines to engage maximum Velocity for their Earthbound journey

    With the Descending rocket used first to capacity then Jettisoned then the Ascending Engine

    The LEM still had Air Supply for two on the Moon

     The only problem was the Air Scrubbers in the two different craft

    Nobody had actually thought about that

    The LEM scrubbers had a Square Fastening to the Duct

    Where the Command Modules were round

     A guy came running out from the Technical Room in Houston control with the two Scrubbers Duck Taped together !!

    Don't leave home without it so they went ahead and copied the design and it helped get them home

    " Snoopy " was sadly jettisoned to burn up in re entry, but it has gone down in History as the LEM that didn't make it to the Moon

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    • Funnelweb
      Lv 7
      1 month agoReport

      The Apollo 13 LEM was called Aquarius, while the Command / Service module was Odyssey. The famous quote "Houston, we've had a problem here." echoes a line by H.A.L. in the movie "2001: A Space Odyssey".

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  • 1 month ago

    Read the book Apollo 13. It details the entire mission.

    A really good read.

    The movie is close, but dramatised and doesn't cover everything.

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  • Clive
    Lv 7
    1 month ago

    Never mind should or shouldn't, it DID.  There was enough fuel in the LEM descent engine to make burns at the right time to change direction and send the whole lot round the Moon and back to Earth.  Obviously they weren't going to need it to land on the Moon now that had been scrubbed.

    Remember that the engine doesn't have to be working all the way, as there's no friction in space - once you're going in the right direction at the right speed, you can turn it off and your spaceship just keeps going in a straight line.  (Newton's good old 1st law of motion!)  All you have to do now is wait.  Keep firing and you just go faster, and then you'll need more fuel to slow down when you get to your destination.  With no friction, all you have to do to keep going at the same speed in a straight line is nothing, as Newton said.  You only need an engine to change direction.

    If the descent engine hadn't had enough fuel, they could have jettisoned the bottom half of the LEM and used the ascent engine as well.  But as it happened, they never needed the ascent engine and it wasn't ever used.  See - you need a huge amount of fuel to get the thing off the Earth and up to escape velocity, so you have to start with a huge rocket, but once that's done, all you need are little nudges.

    There was enough food and water, toilet facilities, what else do you need for life support?  It was dark and cold in the CM because the SM wasn't working, but the LEM's own systems were still working.  The only real problem was air.  Carbon dioxide built up in the LEM and the scrubber cartridges in the two modules were different shapes, but NASA on the ground came up with a way to make the CM ones fit into the LEM scrubber equipment and they followed the instructions.

    So they could eat, drink, breathe, pee, poop and stay warm for long enough to continue on round the Moon and get back.  Stop and turn round wasn't an option - carry on round the Moon used the least fuel.

    • Tom
      Lv 7
      1 month agoReport

      Since the LEM had a smaller engine, they only burned it LONGER for the same course changing effect.

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  • 1 month ago

    >>How was the LEM used as a lifeboat on Apollo 13?

    The Command/Service modules had to be completely powered down. If the astronauts were to survive, the systems of the LM had to sustain them... they rationed the power available by turning everything off, and saving the 3 small reentry batteries in the Command Module for when they were needed. 

    >>The LEM engines should not be powerful enough to propell the Command

    >> and Service modules - that was the Service Module's job. 

    Actually, the LM just needed to correct the course - not propel them.  They *left* free-return trajectory to reach the Fra Mauro highlands; they needed a push by the LM to return to that trajectory - that happened as they were still headed out-bound.  After rounding the moon, they just needed to course-correct, and they did use the LM for a long burn - to accelerate them as much as possible to return to Earth quicker. 

    >>Nor was it designed to sustain three people for four days. 

    Correct. With all systems running, it could sustain 2 astronauts for about a day and half;  with all systems off (except the radio and a fan), the power was stretched for the necessary time home - and, they had a small surplus at the end. 

    >>How did the astronauts ride the LEM all the way home? 

    They used the power sparingly, and as such - they had to endure the cold;  In the command module, temperatures dropped below freezing in some places. 

    Here's a documentary that came out before Apollo 13 - the movie did - it answers all the questions you have... it's very well done:  https://youtu.be/H7cX0Q_sEpk

    Youtube thumbnail

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  • Joseph
    Lv 7
    1 month ago

    Whether or not the LEM engines were designed to propel the Command and Service module, they still did.  The difference is the duration of the burn to get the required velocity change.  A more powerful engine will burn less time, a less powerful will burn longer to get the required delta V.  Since they were not going to land on the Moon, there was no reason to bring all that fuel back.

    And yes, the LEM wasn't designed to sustain three people. The Carbon Dioxide concentration in the LEM did reach elevated level but the engineers on the ground came up with the procedure for the crew to jury rig a system where they could use the Command Module's CO2 scrubber cartridges with the LEM's life support system.  

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