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SpaceX to Send Privately Crewed Dragon Spacecraft Beyond the Moon Next Year

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Re: SpaceX to Send Privately Crewed Dragon Spacecraft Beyond the Moon Next Year

#391

Post by lamontcg »

jessriedel wrote: post #322
Retric wrote: post #318

Earlier quoted context omitted.

SpaceX is already docking with the space station which is similar difficulty as launching from the moon and docking in lunar orbit. The problem is getting a rocket with enough fuel on the surface of the moon without damaging it, not the docking in orbit. Which is even easier than doing the same thing from the surface of Mars. The only advantage of Mars is you don't need to burn fuel slowing down but that's more than…

I don't think either of us know much about this, but I do know that docking with the ISS to unload supplies requires completely different equipment than doing a rendezvous between a lunar lander and a lunar orbiter for Earth return. (That's why I didn't say merely "docking".) The only craft SpaceX has that can land on Earth or the Moon is Dragon. I am pretty sure Dragon does not have enough delta-v to do a full propu…

> I am pretty sure Dragon does not have enough delta-v to do a full propulsive landing on the moon.

The information I'm finding on the internet suggests Dragon 2 should run around 400 m/s of delta-V (it only needs on the order of 200 m/s to go from terminal velocity aerobraking to landed on Earth).

TLI to LLO is 800 m/s, and I'd guess that a Circumlunar return trajectory to LLO transfer would be on that order -- which is already out of the Dragon 2's range and you're only trying to get into orbit on the Moon, not return, and definitely not land or take off again.

Its close enough though that a beefed up Dragon 3 might be able to dock with some kind of space station and refueling dock in lunar orbit, then you just need to have a lunar ferry (Apollo sorta downsized all of this and crammed it all on top of a Saturn V for one-time use -- I'm thinking a bit bigger for the whole system and more cough reusable...)

Re: SpaceX to Send Privately Crewed Dragon Spacecraft Beyond the Moon Next Year

#392

Post by rwmj »

ctdonath wrote: post #116
coryfklein wrote: post #98

Earlier quoted context omitted.

Not sure everyone will see it that way. One could look at it as taking the whole "wasteful private jet" to the extreme. Think of the sheer amount of fuel burned in the earth's atmosphere so a rich guy can fly in space. At least, I expect many will spin it that way.

The flight is a necessary step toward viable interplanetary travel. Even NASA slung people around the Moon before later flights landed thereon. Gotta send a rocket up & around & back, with passengers, to make progress toward the "colony on Mars" goal, so may as well do it with someone willing to fund a good chunk of the excursion.

I actually think today we'd be in a better situation if NASA had stopped there and didn't land on the moon (in the 1960s). Here's my reasoning:

(1) It's much easier to orbit the moon than to land on it.

(2) Both the US and the USSR had the capability to send many people on orbital flights around the moon.

(3) With both the US and USSR orbiting the moon, the space race wouldn't have ended (because both had the same capability and neither had put a flag on the surface).

(4) Once both countries are orbiting the moon for a few years, at some point in the 1970s one or the other would have made a landing.

(5) Both great powers would be competing incrementally in the same space, but at the same time it's not a situation which could have plausibly lead to a war, so it would have been safe for humanity.

Re: SpaceX to Send Privately Crewed Dragon Spacecraft Beyond the Moon Next Year

#395

Post by lorenzhs »

hackuser wrote: post #164
ChuckMcM wrote: post #161

Wow. This sends so many thoughts cascading through my head that I'm dizzy. Some things to consider, 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? Dragon has the deltaV to land on the moon (not sure if it…

> The next person to take a picture of the Earth from moon may not be on a government funded mission. Note that the press release says: Most importantly, we would like to thank NASA, without whom this would not be possible. NASA’s Commercial Crew Program, which provided most of the funding for Dragon 2 development, is a key enabler for this mission. Your tax dollars, if you are American, helped pay for this. Thank yo…

Note that NASA encourages its contractors to use their stuff for private missions as well—building more of the things reduces unit price (by amortising development cost) and thus costs for NASA, so it could be that this results in lower overall cost to US taxpayers. In addition it helps collect more data on safety etc, which is in NASA's interest, too.

Re: SpaceX to Send Privately Crewed Dragon Spacecraft Beyond the Moon Next Year

#396

Post by Tepix »

caseyf7 wrote: post #373
rlanday wrote: post #301

Earlier quoted context omitted.

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.

Which is also the record for Farthest Humans From Earth. Any chance they can pass up the chance to break that record?

Yep, they plan to go as far as 400.000 miles from earth, that's quite a bit farther out than Apollo astronauts ever went (less than 300.000 miles).

Re: SpaceX to Send Privately Crewed Dragon Spacecraft Beyond the Moon Next Year

#397

Post by Tepix »

Cerium wrote: post #240
ChuckMcM wrote: post #192

Earlier quoted context omitted.

As a taxpayer (who was just reminded this past weekend of how much that is :-) I'm really glad that NASA had enough budget to spend on the Commercial Crew program. Given that the NASA budget of $18.5B[1] is a rounding error on the overall budget $3,540B[2], seriously it's a half a percent. And commercial crew was only $1.2B [ibid] of that NASA budget. So less than .05%. Again rounding error. And with that money they…

If instead of increasing military spending 54 billion, we gave it all to NASA, we could be quadrupling NASA's budget.

NASA should pass it on to Elon.

If we establish a permanent Mars colony, that would really increase security for all of mankind.

Building more nuclear weapons is NOT increasing security.

Re: SpaceX to Send Privately Crewed Dragon Spacecraft Beyond the Moon Next Year

#398

Post by simonh »

nojvek wrote: post #376
Retric wrote: post #331

Earlier quoted context omitted.

Sorry, butchered that. I was trying to say the figures are less exact depending on how hard you want to hit the earths upper atmosphere. ~8.2km/s if you want to end up in earth LEO ~8km/s if you want to get back to the earth. You can also save a little if your sending an unmanned craft and don't care how long it takes or skip low moon orbit.

I wonder if spaceX is going to send a permanent colony of bots on moon to make a base there. The latency is a lot lower than Mars and would make a good start. Sending a couple of humans around moon for tourism is a waste of resources.

They're said they have no particular interest in going to the Moon as it wouldn't teach them anything useful about going to or living on Mars and would just be a distraction. Of course if someone else wants to contract them to do so and they can make a buck off it, that might be different.

Re: SpaceX to Send Privately Crewed Dragon Spacecraft Beyond the Moon Next Year

#399

Post by grkvlt »

Retric wrote: post #318
jessriedel wrote: post #253

Earlier quoted context omitted.

Right. SpaceX doesn't have a craft capable of 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 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 u…

SpaceX is already docking with the space station which is similar difficulty as launching from the moon and docking in lunar orbit. The problem is getting a rocket with enough fuel on the surface of the moon without damaging it, not the docking in orbit. Which is even easier than doing the same thing from the surface of Mars. The only advantage of Mars is you don't need to burn fuel slowing down but that's more than…

Actually, they are Berthing[1][2] the Dragon craft with the ISS, which means something slightly different - grabbed by the thing you are connecting to and pulled in, vs. a (controlled) bumping into the thing. I believe that Nautical terminology is where that comes from, and means the same there e.g. berthing ships with ropes and dock hands.

1. https://en.wikipedia.org/wiki/Docking_and_berthing_of_spacec...

2. http://space.stackexchange.com/questions/13665/what-is-the-d...

Re: SpaceX to Send Privately Crewed Dragon Spacecraft Beyond the Moon Next Year

#400

Post by simonh »

ChuckMcM wrote: post #192
hackuser wrote: post #164

Earlier quoted context omitted.

> The next person to take a picture of the Earth from moon may not be on a government funded mission. Note that the press release says: Most importantly, we would like to thank NASA, without whom this would not be possible. NASA’s Commercial Crew Program, which provided most of the funding for Dragon 2 development, is a key enabler for this mission. Your tax dollars, if you are American, helped pay for this. Thank yo…

As a taxpayer (who was just reminded this past weekend of how much that is :-) I'm really glad that NASA had enough budget to spend on the Commercial Crew program. Given that the NASA budget of $18.5B[1] is a rounding error on the overall budget $3,540B[2], seriously it's a half a percent. And commercial crew was only $1.2B [ibid] of that NASA budget. So less than .05%. Again rounding error. And with that money they…

A lot of what any government does is a rounding error on the overall budget, but are still absolutely vital. Those rounding errors don't half add up quickly. I'm pro-space exploration and believe it's worth funding, but this particular argument doesn't strike me as useful. Space exploration and technology development should justify it's costs on the same basis as any other government programs, any number of which of which could be revolutionized by 'small' increases in the overall budget.
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