Author Topic: SpaceX Crewed Dragon Circumlunar Mission (Read 515425 times)

QuantumG · « **Reply #1100 on:** 04/01/2017 03:10 am »

Maybe he was just saying it's too risky for him. Everyone gets to make that decision for themselves.

Kaputnik · « **Reply #1101 on:** 04/01/2017 11:03 am »

Quote from: QuantumG on 04/01/2017 03:10 am

Maybe he was just saying it's too risky for him. Everyone gets to make that decision for themselves.

I think that's too narrow a view.
If a mission goes bad and people die, that's going to affect everybody who is involved, unless they are psychopaths.

MATTBLAK · « **Reply #1102 on:** 04/01/2017 11:06 am »

I remember the statement that Deke Slayton made in his biography about risk. He was talking in context about the loss of Challenger, the 25th Shuttle mission. He reckoned that if there had been 25 Lunar Landing missions; he guaranteed they would have killed a crew by then.

TrevorMonty · « **Reply #1103 on:** 04/01/2017 02:02 pm »

I think flyby is good idea but would like see an unmanned Dragon do it first.

RDoc · « **Reply #1104 on:** 04/01/2017 03:52 pm »

If Red Dragon actually happens that would be a good confidence builder, but other than that, is there any entity that would pay for any FH Dragon mission, much less an unmanned Lunar flyby demo?

I suppose if there's a real queue for tourists who want to fly deep space missions, maybe SpaceX itself would fund it, but that seems like a pretty big stretch.

billh · « **Reply #1105 on:** 04/01/2017 04:03 pm »

Quote from: Zed_Noir on 03/30/2017 02:37 am

@Space Ghost 1962

Do you think the Chinese government got spooked by the SX circumlunar announcement? Especially just before the SES-10 launch with "flight proven" hardware. So as to accelerate their Space program development.

I'll tell you who spooks me...Space Ghost!!

Space Ghost 1962 · « **Reply #1106 on:** 04/01/2017 05:56 pm »

Quote from: billh on 04/01/2017 04:03 pm

Quote from: Zed_Noir on 03/30/2017 02:37 am
@Space Ghost 1962

Do you think the Chinese government got spooked by the SX circumlunar announcement? Especially just before the SES-10 launch with "flight proven" hardware. So as to accelerate their Space program development.

I'll tell you who spooks me...Space Ghost!!

One of the many reasons for the name ...

Ludus · « **Reply #1107 on:** 04/01/2017 06:02 pm »

Quote from: TrevorMonty on 04/01/2017 02:02 pm

I think flyby is good idea but would like see an unmanned Dragon do it first.

FH Demo flight could throw a reused Cargo Dragon on the same path with just a cheese onboard.

ChrisWilson68 · « **Reply #1108 on:** 04/01/2017 06:21 pm »

Quote from: Kaputnik on 04/01/2017 11:03 am

Quote from: QuantumG on 04/01/2017 03:10 am
Maybe he was just saying it's too risky for him. Everyone gets to make that decision for themselves.

I think that's too narrow a view.
If a mission goes bad and people die, that's going to affect everybody who is involved, unless they are psychopaths.

People also get to choose which companies they work for. SpaceX gets to choose what level of risk it is willing to take and passengers are free to choose to take that risk or not, and potential employees get to choose whether or not they work for a company that is willing to take that level of risk.

I, for one, am glad there are people willing to take such risks, and other people willing to help them take such risks, to advance our expansion into space.

guckyfan · « **Reply #1109 on:** 04/01/2017 06:38 pm »

Quote from: Ludus on 04/01/2017 06:02 pm

Quote from: TrevorMonty on 04/01/2017 02:02 pm
I think flyby is good idea but would like see an unmanned Dragon do it first.

FH Demo flight could throw a reused Cargo Dragon on the same path with just a cheese onboard.

Landing a second stage coming in from a lunar flyby would be a real test.

MATTBLAK · « **Reply #1110 on:** 04/02/2017 12:43 am »

In order to send a Dragon on a lunar flyby; the second stage would also be on TLI - it would not be coming back. And shielding the second stage enough the survive a nearly 25,000 mph re-entry like a capsule would not really be viable.

guckyfan · « **Reply #1111 on:** 04/02/2017 02:02 am »

Quote from: MATTBLAK on 04/02/2017 12:43 am

In order to send a Dragon on a lunar flyby; the second stage would also be on TLI - it would not be coming back. And shielding the second stage enough the survive a nearly 25,000 mph re-entry like a capsule would not really be viable.

I was refering to the announcement by Elon Musk, they will try to get the second stage down. This is not compatible with sending a Dragon around the moon unless we want to assume the stage can do the loop together with the Dragon and then reenter. Sounds really unlikely to me.

MATTBLAK · « **Reply #1112 on:** 04/02/2017 02:28 am »

I doubt they'll be sending anything Circumlunar on the first Falcon Heavy flight - so that would free them up for a recovery attempt. But if they were going Circumlunar - there's no way that upper stage would be coming back; it's needed for TLI.

QuantumG · « **Reply #1113 on:** 04/02/2017 05:10 am »

Do you think they're planning a direct insertion or a separate TLI burn after entering a parking orbit?

I'd been assuming direct, but I can't honestly say why.

MATTBLAK · « **Reply #1114 on:** 04/02/2017 05:39 am »

You could do a direct burn; though I imagine a more precise launch window would be required - but I don't know anywhere near enough about orbital mechanics to say for sure. Otherwise, like Apollo I'd think there would be a coast after first burn, then a relight at the appropriate moment after nearly 2x Earth orbits.

Comga · « **Reply #1115 on:** 04/02/2017 05:48 am »

Quote from: QuantumG on 04/02/2017 05:10 am

Do you think they're planning a direct insertion or a separate TLI burn after entering a parking orbit?

I'd been assuming direct, but I can't honestly say why.

A technical question?
What do you think this is? NSF?

Yes. Thank you.

I always assumed the opposite, that they would send the Dragon and second stage into a parking orbit.
It's the "Apollo thing to do" but maybe that's just what I remember. Take time to check out the capsule before losing the ability to abort. It does however require an extended duration for the second stage.

What other considerations do people see?

Then maybe we can discuss my original question of where they plan to come down, in the ocean or on land

QuantumG · « **Reply #1116 on:** 04/02/2017 05:57 am »

Surely that orbit-and-a-half duration has already been proven a bunch of times now.

Comga · « **Reply #1117 on:** 04/02/2017 06:09 am »

Quote from: QuantumG on 04/02/2017 05:57 am

Surely that orbit-and-a-half duration has already been proven a bunch of times now.

OK. That issue has been put to bed.
Why else would you assume direct injection?
Does it make it easier or harder, more or fewer, longer or shorter windows?

QuantumG · « **Reply #1118 on:** 04/02/2017 06:35 am »

Quote from: Comga on 04/02/2017 06:09 am

Why else would you assume direct injection?
Does it make it easier or harder, more or fewer, longer or shorter windows?

I honestly don't see an advantage. I think it's just all these old thoughts sitting on hold in my head while SpaceX slowly improves their capabilities making them irrelevant.

Comga · « **Reply #1119 on:** 04/02/2017 04:53 pm »

Please stop with the diversions. This thread is about the announced cislunar mission.
I would hope it concentrates on what SpaceX WILL DO, not speculations about fanciful additions.
We are getting to the level of asking what Zephram Cochrane would add to the trunk.
Let's stick to what Musk wants flown, and how and when.