5 ms·

Simulating the Apollo 11 LM Ascent Stage Orbit [pdf]

54 points by marbu 5y ago

everyone 5y ago
Scott Manley did a video on this. Apparently the ascent stage could still be in orbit as we speak. https://youtu.be/dBHbLV7xEhc https://youtu.be/dBHbLV7xEhc
- MayeulC 5y ago
  https://news.ycombinator.com/item?id=27865232 https://news.ycombinator.com/item?id=27865232
imglorp 5y ago
Suppose it's in a stable orbit and we want to preserve it for historical artifact value, for study by the public. Should we leave it where it is? Visitors could go match orbits and observe it in flight. Should we create a static display monument on the surface, with a plaque, like the USS Arizona? If you say bring the LM back to the Smithsonian, for atmospheric entry you'd need something like a Starship with a widely opening fairing, a rigid mounting system inside, and maybe a manipulator arm of some kind to capture.
- marbu 5y ago
  Assuming the orbit is and remains stable, the best way to preserve it would be to keep it where it is now. But I'm not sure we can assume that the orbit remains stable in the long term, even if we confirm via observation that the orbit is stable now (few issues I see here includes increasing number of satellites orbiting Moon, asteroid impacts and fly-bys, ...).
  - jcims 5y ago
    It really feels like we’re not that far away from space tugs that can latch on to a satellite and nudge its orbit to desired parameters. Given that it would have to have a high thrust-to-weight ratio, you could probably push things pretty deep, relatively speaking, into the atmosphere so that they would have a high decay rate while the tug can muscle its way back out.
    - fergbrain 5y ago
      Northrop Grumman already have the MEV-2, which does just that: https://www.theverge.com/2021/4/12/22380581/northrop-grumman-mev-2-satellite-servicing-intelsat-mrv-docked https://www.theverge.com/2021/4/12/22380581/northrop-grumman...
      - messe 5y ago
        The issue with latching onto it with something like the MEV-2 is that the LEM, if it's still in orbit, is almost certainly tumbling. That makes an automated intercept / latching-onto non-trivial, to say the least.
        skykooler 5y ago
        I wonder how feasible it would be to surround it with a coil of wire carrying a strong electric current, to slow its rotation via magnetic induction?
        jcims 5y ago
        You might be able to harpoon it with a wound-up yoyo on a stick. https://www.youtube.com/watch?v=ZKAQtB5Pwq4&t=390s https://www.youtube.com/watch?v=ZKAQtB5Pwq4&t=390s
- scrooched_moose 5y ago
  Theoretically, it could have easily returned to Earth with the Space Shuttle, assuming another vehicle could rendezvous and transport it to LEO. The Ascent State was 2.8 x 4.2 x 4.04m with a dry mass of 2150 kg. The Shuttle's cargo bay was 18 x 4.6 x 4.6m (at least...can't find a depth weirdly) with a return-to-Earth payload capacity of 14,400 kg.
- numpad0 5y ago
  Suspend it in the Smithsonian museum Bezos Jr Center made out of surplus habitat cylinders without atmosphere, run a couple tubes and rails around so visitors can ride on robotic arms to get close
bronson 5y ago
The blog article includes more detail & discussion: https://snoopy.rogertwank.net/2020/09/has-eagle-landed.html?m=1 https://snoopy.rogertwank.net/2020/09/has-eagle-landed.html?...

54 points by marbu 5y ago

Scott Manley did a video on this. Apparently the ascent stage could still be in orbit as we speak. https://youtu.be/dBHbLV7xEhc https://youtu.be/dBHbLV7xEhc

MayeulC 5y ago
https://news.ycombinator.com/item?id=27865232 https://news.ycombinator.com/item?id=27865232

imglorp 5y ago

Suppose it's in a stable orbit and we want to preserve it for historical artifact value, for study by the public. Should we leave it where it is? Visitors could go match orbits and observe it in flight. Should we create a static display monument on the surface, with a plaque, like the USS Arizona? If you say bring the LM back to the Smithsonian, for atmospheric entry you'd need something like a Starship with a widely opening fairing, a rigid mounting system inside, and maybe a manipulator arm of some kind to capture.

marbu 5y ago
Assuming the orbit is and remains stable, the best way to preserve it would be to keep it where it is now. But I'm not sure we can assume that the orbit remains stable in the long term, even if we confirm via observation that the orbit is stable now (few issues I see here includes increasing number of satellites orbiting Moon, asteroid impacts and fly-bys, ...).
- jcims 5y ago
  It really feels like we’re not that far away from space tugs that can latch on to a satellite and nudge its orbit to desired parameters. Given that it would have to have a high thrust-to-weight ratio, you could probably push things pretty deep, relatively speaking, into the atmosphere so that they would have a high decay rate while the tug can muscle its way back out.
  - fergbrain 5y ago
    Northrop Grumman already have the MEV-2, which does just that: https://www.theverge.com/2021/4/12/22380581/northrop-grumman-mev-2-satellite-servicing-intelsat-mrv-docked https://www.theverge.com/2021/4/12/22380581/northrop-grumman...
    - messe 5y ago
      The issue with latching onto it with something like the MEV-2 is that the LEM, if it's still in orbit, is almost certainly tumbling. That makes an automated intercept / latching-onto non-trivial, to say the least.
      - skykooler 5y ago
        I wonder how feasible it would be to surround it with a coil of wire carrying a strong electric current, to slow its rotation via magnetic induction?
        jcims 5y ago
        You might be able to harpoon it with a wound-up yoyo on a stick. https://www.youtube.com/watch?v=ZKAQtB5Pwq4&t=390s https://www.youtube.com/watch?v=ZKAQtB5Pwq4&t=390s
scrooched_moose 5y ago
Theoretically, it could have easily returned to Earth with the Space Shuttle, assuming another vehicle could rendezvous and transport it to LEO. The Ascent State was 2.8 x 4.2 x 4.04m with a dry mass of 2150 kg. The Shuttle's cargo bay was 18 x 4.6 x 4.6m (at least...can't find a depth weirdly) with a return-to-Earth payload capacity of 14,400 kg.
numpad0 5y ago
Suspend it in the Smithsonian museum Bezos Jr Center made out of surplus habitat cylinders without atmosphere, run a couple tubes and rails around so visitors can ride on robotic arms to get close

bronson 5y ago

The blog article includes more detail & discussion: https://snoopy.rogertwank.net/2020/09/has-eagle-landed.html?m=1 https://snoopy.rogertwank.net/2020/09/has-eagle-landed.html?...