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> China has been working up to getting a space capability to send people to the Moon with the full backing of the government funding, by 2035[1]. They started i

> China has been working up to getting a space capability to send people to the Moon with the full backing of the government funding, by 2035[1]. They started in 2003. SpaceX was founded in 2002 and they are saying they will fly someone around the moon next year? I don't want to downplay SpaceX at all because I'm a huge fan, but isn't flying someone to the moon (and presumably back) more complicated than just flying around the moon and back? As I understand, apart from the challenge of achieving orbital velocity (no small feat), flying around the moon might require ~41% more velocity (assuming escape velocity to orbital velocity being a ratio of something like sqrt(2):1) and you can use the moon's gravity to redirect you back to earth, whereas landing on the moon and returning requires even more energy (slowing down to land + escaping the moon and returning), not to mention the various other technical requirements involved with the landing itself. "Beyond the moon" makes this sound like it'll be a greater achievement than the Apollo moon landings, but I'm not sure that's really true. Don't get me wrong, the fact that it's a private (ish) company doing this is incredible, just not quite "moon landing" incredible... yet.

lisper 10y ago
Yes, that is exactly right. They are not going to land, for exactly the reasons you say.
jessriedel 10y ago
Right. SpaceX doesn't have a craft capable of lunar orbit rendezvous https://en.wikipedia.org/wiki/Lunar_orbit_rendezvous https://en.wikipedia.org/wiki/Lunar_orbit_rendezvous so they would need to return to the Earth directly from the surface of the moon https://en.wikipedia.org/wiki/Direct_ascent https://en.wikipedia.org/wiki/Direct_ascent Direct ascent requires a much larger initial launch mass, i.e., a larger rocket than has ever been built. Since it took the massive Saturn V to complete the Apollo missions using lunar rendezvous, and SpaceX's Falcon Heavy is smaller, I don't think they are even close to having the ability to land on the moon and return. (And that's assuming there's not other insurmountable factors preventing Dragon from landing on the moon and taking off, which there probably are.) Hopefully someone with more knowledge can chime in.
- XorNot 10y ago
  SpaceX for a landing mission wouldn't try and build a larger rocket, they'd definitely argue to just do multiple launches instead. Fuel tankering is within their area of interest for Mars.
  - ChuckMcM 10y ago
    I believe this (mating tanks given multiple missions) is what they were considering. Imagine you have your reusable falcon 9 boost into orbit a 'fuel only' second stage. Land the first stage, put another one on it, and send it up again. Once you have your 'boost pack' up in orbit, presumably docking with each other into a single unit, you launch your crew which attaches to the 'tug' that takes them to the moon. ULA has a great writeup of how you might do this if you have on orbit refueling capabilities. And on the one hand it seems like total science fiction but on the other, Elon is talking about next year.
    - yellowapple 10y ago
      This can be applied to much more than just fuel, mind you. Interplanetary manned vehicles might very well end up looking like space stations, with a bunch of modules docked together in order to provide the necessary creature comforts to sustain a crew for months on end. In fact, a permanently-in-orbit transfer vehicle might make sense here; have this vehicle run the actual Earth<->Mars transfers, then just shuttle in fuel/supplies/crew on each Earth arrival. Either way, a Falcon-like reusable launch system makes plenty of sense here in terms of making this sort of thing possible.
      - pheldagryph 10y ago
        > a permanently-in-orbit transfer vehicle might make sense here Buzz Aldrin is a big proponent of this approach: https://buzzaldrin.com/space-vision/rocket_science/aldrin-mars-cycler/ https://buzzaldrin.com/space-vision/rocket_science/aldrin-ma...
    - skookumchuck 10y ago
ChuckMcM 10y ago
Between flying to the moon and back (no landing) the only difference is fuel and consumables (air/food). The key capabilities are launch, landing, spacecraft communication and operations, and navigational support for computing and executing maneuvers to get into (and out of) a trans-lunar orbit. The more fuel you have the easier it is on the equipment. Or to put it differently, the difference is that when you get to the Moon you make an orbital injection burn in order to slow yourself down to the point that you can stay in lunar orbit, and then when your done you make another burn to put you back into the trans-lunar orbit. When you get back you can either do a high speed re-entry or you can do an Earth orbit injection burn. You still need a vehicle that can carry people for the duration of the trip. You need to get it into a translunar orbit so that you can get out to the Moon. You need to be able to precisely locate yourself in space relative to the Earth-Moon system and course correct to achieve your orbit goals. All of that stuff has to happen either way. There is an excellent discussion of the various orbit options for getting to the moon in this paper: http://www.esa.int/esapub/bulletin/bullet103/biesbroek103.pdf http://www.esa.int/esapub/bulletin/bullet103/biesbroek103.pd... definitely worth looking over to get a better appreciation on what is involved.
rlanday 10y ago
It's not a greater achievement than the Apollo moon landings (it's basically the mission flown on Apollo 13, swinging around the moon without going into orbit and then coming back), but it's still something that hasn't been done since the Apollo 17 mission in 1972.
- foobarbecue 10y ago
  Hopefully more like Apollo 8 than 13!
  - cswilly 10y ago
    I understand that SpaceX is not proposing to orbit the moon. Therefore it is more like Apollo 13. Apollo 8 orbited the moon.
    - sqeaky 10y ago
      Somehow I think the details of flyby vs orbit were not the intended subject I suspect he wants a generally smooth mission like what Apollo 8 and to avoid any unplanned rapid disassembly like what Apollo 13 had.
    - foobarbecue 10y ago
      Good point cswilly, I didn't think of that part! And yeah, I meant let's try and not explode stuff too much...
- astrodust 10y ago
  Hurray for progress! We're able to repeat what was done in 1972!
  - dwg 10y ago
    For a fraction of the cost.
    - astrodust 10y ago
saganus 10y ago
Well, it says in the article: "Once operational Crew Dragon missions are underway for NASA, SpaceX will launch the private mission on a journey to circumnavigate the moon and return to Earth." I don't know why people are arguing over whether they are landing or not...
- vans 10y ago
  because no one read the article :)

lisper 10y ago

Yes, that is exactly right. They are not going to land, for exactly the reasons you say.

jessriedel 10y ago

Right. SpaceX doesn't have a craft capable of lunar orbit rendezvous https://en.wikipedia.org/wiki/Lunar_orbit_rendezvous https://en.wikipedia.org/wiki/Lunar_orbit_rendezvous so they would need to return to the Earth directly from the surface of the moon https://en.wikipedia.org/wiki/Direct_ascent https://en.wikipedia.org/wiki/Direct_ascent Direct ascent requires a much larger initial launch mass, i.e., a larger rocket than has ever been built. Since it took the massive Saturn V to complete the Apollo missions using lunar rendezvous, and SpaceX's Falcon Heavy is smaller, I don't think they are even close to having the ability to land on the moon and return. (And that's assuming there's not other insurmountable factors preventing Dragon from landing on the moon and taking off, which there probably are.) Hopefully someone with more knowledge can chime in.

XorNot 10y ago
SpaceX for a landing mission wouldn't try and build a larger rocket, they'd definitely argue to just do multiple launches instead. Fuel tankering is within their area of interest for Mars.
- ChuckMcM 10y ago
  I believe this (mating tanks given multiple missions) is what they were considering. Imagine you have your reusable falcon 9 boost into orbit a 'fuel only' second stage. Land the first stage, put another one on it, and send it up again. Once you have your 'boost pack' up in orbit, presumably docking with each other into a single unit, you launch your crew which attaches to the 'tug' that takes them to the moon. ULA has a great writeup of how you might do this if you have on orbit refueling capabilities. And on the one hand it seems like total science fiction but on the other, Elon is talking about next year.
  - yellowapple 10y ago
    This can be applied to much more than just fuel, mind you. Interplanetary manned vehicles might very well end up looking like space stations, with a bunch of modules docked together in order to provide the necessary creature comforts to sustain a crew for months on end. In fact, a permanently-in-orbit transfer vehicle might make sense here; have this vehicle run the actual Earth<->Mars transfers, then just shuttle in fuel/supplies/crew on each Earth arrival. Either way, a Falcon-like reusable launch system makes plenty of sense here in terms of making this sort of thing possible.
    - pheldagryph 10y ago
      > a permanently-in-orbit transfer vehicle might make sense here Buzz Aldrin is a big proponent of this approach: https://buzzaldrin.com/space-vision/rocket_science/aldrin-mars-cycler/ https://buzzaldrin.com/space-vision/rocket_science/aldrin-ma...
  - skookumchuck 10y ago

ChuckMcM 10y ago

Between flying to the moon and back (no landing) the only difference is fuel and consumables (air/food). The key capabilities are launch, landing, spacecraft communication and operations, and navigational support for computing and executing maneuvers to get into (and out of) a trans-lunar orbit. The more fuel you have the easier it is on the equipment. Or to put it differently, the difference is that when you get to the Moon you make an orbital injection burn in order to slow yourself down to the point that you can stay in lunar orbit, and then when your done you make another burn to put you back into the trans-lunar orbit. When you get back you can either do a high speed re-entry or you can do an Earth orbit injection burn. You still need a vehicle that can carry people for the duration of the trip. You need to get it into a translunar orbit so that you can get out to the Moon. You need to be able to precisely locate yourself in space relative to the Earth-Moon system and course correct to achieve your orbit goals. All of that stuff has to happen either way. There is an excellent discussion of the various orbit options for getting to the moon in this paper: http://www.esa.int/esapub/bulletin/bullet103/biesbroek103.pdf http://www.esa.int/esapub/bulletin/bullet103/biesbroek103.pd... definitely worth looking over to get a better appreciation on what is involved.

rlanday 10y ago

It's not a greater achievement than the Apollo moon landings (it's basically the mission flown on Apollo 13, swinging around the moon without going into orbit and then coming back), but it's still something that hasn't been done since the Apollo 17 mission in 1972.

foobarbecue 10y ago
Hopefully more like Apollo 8 than 13!
- cswilly 10y ago
  I understand that SpaceX is not proposing to orbit the moon. Therefore it is more like Apollo 13. Apollo 8 orbited the moon.
  - sqeaky 10y ago
    Somehow I think the details of flyby vs orbit were not the intended subject I suspect he wants a generally smooth mission like what Apollo 8 and to avoid any unplanned rapid disassembly like what Apollo 13 had.
  - foobarbecue 10y ago
    Good point cswilly, I didn't think of that part! And yeah, I meant let's try and not explode stuff too much...
astrodust 10y ago
Hurray for progress! We're able to repeat what was done in 1972!
- dwg 10y ago
  For a fraction of the cost.
  - astrodust 10y ago

saganus 10y ago

Well, it says in the article: "Once operational Crew Dragon missions are underway for NASA, SpaceX will launch the private mission on a journey to circumnavigate the moon and return to Earth." I don't know why people are arguing over whether they are landing or not...

vans 10y ago
because no one read the article :)