Poll

Will there be an unmanned test flight around Luna before they send people around Luna?

Yes
55 (51.9%)
No
51 (48.1%)

Total Members Voted: 106

Voting closed: 06/18/2017 07:13 PM


Author Topic: Unmanned Grey Dragon test flight around Luna before manned flight around Luna?  (Read 4371 times)

Offline gospacex

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NASA has no problem putting people on the first launch of anything they build.
Had no problem.  Today's NASA is not your grandfather's NASA.

OTOH, NASA can't tell SpaceX that they are not allowed to launch a manned craft, as long as the flight has nothing to do with any NASA assets.

Offline hop

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Apollo tested the rocket and the spacecraft, but didn't send it to the moon before they put people on it.
They did test high speed re-entry and various other mission specific aspect of the flight though.

The Soviet Zond program also attempted all-up test flights, and would have required two successes before sending crew. This turned out to be a good decision.

A number of people have stated that Dragon is fine for lunar return. IIRC this goes back to comments by Elon, but it's not obvious to me what level of analysis it's based on. Things that seem OK at a BOTE level sometimes turn out to be less certain under rigorous analysis.

I certainly think SpaceX would have a decent chance of success on the first try, but it also seems likely that dedicated tests would significantly reduce risk. It will be interesting to see what they choose, if the mission actually flies.

Offline Lar

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Which part of this tests the ability to navigate to and around the moon with sufficient precision (and the ability to make course corrections) to make it back? I don't guess it needs to be a Dragon.
FH with D1, if slung around Luna.
"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk
"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

Offline RocketmanUS

Voted Yes

Would you want to be the paying customer on an untested craft beyond LEO. I would expect they would want it tested first.
What about the added radiation beyond LEO?
Mars and beyond, human exploration
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Offline kevinof

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This gets my vote. They will be testing Heavy, have a lot of used D1's around so why not send it on a jaunt out and back. Would get them some good data, test the nav and comms and especially the heat shield. Seems the obvious way to go.


Which part of this tests the ability to navigate to and around the moon with sufficient precision (and the ability to make course corrections) to make it back? I don't guess it needs to be a Dragon.
FH with D1, if slung around Luna.

Offline darkenfast

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What is likely to bite them if they only test Dragon in LEO, as opposed to BEO?  Is there something not understood about heat shield technology that SpaceX might not take into account?  The engineering for heat shields at that velocity has been fairly well researched and proven.  Radiation?  Well, we know what the levels are and what is needed to protect people and electronics.  GNC?  This might be the trickiest area, but again, is it harder than what SpaceX does now with the various orbits it delivers to?  Life Support?  What about the system would be different than a multi-day flight in LEO, other than it takes longer to get back on the ground (which is the biggest risk in this whole scenario)? 

As noted above, Apollo 8 flew to the moon because the one manned test of Apollo 7 in LEO gave NASA and the astronauts the confidence to do so.  We have a lot more experience.  The two people who are paying for this are probably not stupid.  They will have the information to make an intelligent choice and I think they will go for it without benefit of an unmanned test flight beyond LEO.
 

Online guckyfan

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I find it very interesting how undecided this poll is.

BTW it was a NASA study for Inspiration Mars that evaluated PicaX and found it capable of surviving even the very high speed of reentry from the free return trajectory from Mars. That was for an older version of PicaX.

Offline TaurusLittrow

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As noted above, Apollo 8 flew to the moon because the one manned test of Apollo 7 in LEO gave NASA and the astronauts the confidence to do so.   

True for NASA management at the time especially after Apollo 7 was deemed "101 percent" successful. I think Frank Borman would have flown Apollo 8 around the moon regardless (with Lovell and Anders in tow). Borman was a no-nonsense cold warrior and has been quoted as saying the mission was more important than his life. You have to love the guy.

Offline hop

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As noted above, Apollo 8 flew to the moon because the one manned test of Apollo 7 in LEO gave NASA and the astronauts the confidence to do so.
NASA flew Apollo 4 and 6 uncrewed, beyond LEO before that.

Offline robert_d

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BTW it was a NASA study for Inspiration Mars that evaluated PicaX and found it capable of surviving even the very high speed of reentry from the free return trajectory from Mars. That was for an older version of PicaX.

The PicaX may survive, but what about the rest of the spacecraft? Specifically, I thought the shape of the Apollo capsule was chosen to avoid the plasma wake upon the high-speed return. Obviously the folks at SpaceX have modeled this, but wouldn't you want to be sure that those super draco pods weren't going to do something like what the broken wing on Columbia did?

Offline darkenfast

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As noted above, Apollo 8 flew to the moon because the one manned test of Apollo 7 in LEO gave NASA and the astronauts the confidence to do so.
NASA flew Apollo 4 and 6 uncrewed, beyond LEO before that.

They didn't fly anywhere near the Moon.  I don't believe that they were of very long duration, either, but were basically just to test the heatshield.   We know a lot more about heatshields now.

Offline rpapo

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As noted above, Apollo 8 flew to the moon because the one manned test of Apollo 7 in LEO gave NASA and the astronauts the confidence to do so.
NASA flew Apollo 4 and 6 uncrewed, beyond LEO before that.

They didn't fly anywhere near the Moon.  I don't believe that they were of very long duration, either, but were basically just to test the heatshield.   We know a lot more about heatshields now.
The Apollo 4 test was considerably higher and faster than even the Orion EFT-1 test, though it seems that in the case of EFT-1 they may have been more concerned with radiation testing than with reentry testing.  Apollo 4 was also about testing the Service Module, which they used to improve the realism of the reentry by altering and speeding up the return trajectory.

Such a test would be useful for Dragon 2, both to test the reentry characteristics and the behavior under higher radiation levels in the Van Allen belts.

Essential?  That's somebody's judgement call.
An Apollo fanboy . . . fifty years ago.

Online rockets4life97

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Elon has said he thinks the radiation concern is overplayed. I doubt he would choose to do a manned BLEO test flight on the basis of radiation concerns.

Offline Roy_H

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Elon has said he thinks the radiation concern is overplayed. I doubt he would choose to do a manned BLEO test flight on the basis of radiation concerns.

Was that statement concerning humans or electronics?

I think they should verify their capability to do the flight, verify radiation levels inside the capsule, verify communications at moon orbit, not just say according to our calculations everything will be ok. I voted yes.
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Offline oldAtlas_Eguy

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Elon has said he thinks the radiation concern is overplayed. I doubt he would choose to do a manned BLEO test flight on the basis of radiation concerns.

Was that statement concerning humans or electronics?

I think they should verify their capability to do the flight, verify radiation levels inside the capsule, verify communications at moon orbit, not just say according to our calculations everything will be ok. I voted yes.
From the standpoint of real data on radiation they have multiple data sets on the radiation inside and outside of the CRS Dragons to model the interior radiation levels from external radiation levels. Many more than what Apollo had. Dragon 2 and Dragon 1 share significant structural and shape heritage. Also the van Allen belts are now highly modeled vs what they were at the time of Apollo. So a little math and physics will result in highly accurate predictions of radiation levels in the interior. Plus they have had multiple reentries to validate the reentry models of the Dragon. It only needs the tweaks from real data from a few reentries of D2.

In all I believe the risks for the D2 Lunar flight without a precursor is less than those that the Apollo 8 mission faced. How much less is probably only known by SpaceX and their two customers at this point.

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