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 6010 times)

Online guckyfan

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I vote no. There is no need to do one. The risks are mitigated by Crew Dragon flying to the ISS and Falcon Heavy flying a number of missions first. Given the plentiful data on how PicaX performs from LEO they can trust models for reentry with lunar return speed.
« Last Edit: 05/19/2017 07:13 PM by Lar »

Offline sdsds

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Re: Unmanned Grey Dragon test flight before manned flight?
« Reply #1 on: 05/19/2017 09:33 AM »
I agree there is no need for one but believe it is likely they will conduct such a mission anyway. Yes it will incur costs but those will be outweighed by the benefits.
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Offline TaurusLittrow

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Re: Unmanned Grey Dragon test flight before manned flight?
« Reply #2 on: 05/19/2017 10:24 AM »
I vote no. There is no need to do one. The risks are mitigated by Crew Dragon flying to the ISS and Falcon Heavy flying a number of missions first. Given the plentiful data on how PicaX performs from LEO they can trust models for reentry with lunar return speed.

Exactly. This is like sailing around the world. Pay for the boat and travel at your own risk (well, once the FAA signs off). Seriously though, Apollo 8 circumnavigated the moon (with three astronauts and national prestige aboard) w/o a prior unmanned lunar loop. That was half a century ago and presumably the technology for deep space communication and navigation has advanced since then. Besides, just last week NASA was considering "manning" EM-1 w/o a full up test of the heat shield or ECLSS and only decided against it because of financial (not technical) reasons. So I vote no. "You pays your money and you takes your chance."

Online FutureSpaceTourist

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Re: Unmanned Grey Dragon test flight before manned flight?
« Reply #3 on: 05/19/2017 01:08 PM »
I'm really torn on this one but in the end voted yes.

Unlike Apollo 8, there's no pressing reason to rush this. Elon has said about commercial crew that he wants to do everything possible to ensure their safety, surely the same goes here?

I fully agree they don't have to do an unmanned mission, but why take the risk?

Offline Cherokee43v6

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Re: Unmanned Grey Dragon test flight before manned flight?
« Reply #4 on: 05/19/2017 01:18 PM »
While I voted no,  I always felt that it would be a great marketing stunt if the first launch of the heavy sent a pre-flown dragon on a free-return trajectory around the moon.
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Offline clongton

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Re: Unmanned Grey Dragon test flight before manned flight?
« Reply #5 on: 05/19/2017 01:28 PM »
SpaceX has already said there will be an unmanned flight as part of the certification process. It will be the very first flight of Dragon2. There is no way that SpaceX would do anything so dumb as to make the very first flight of Dragon2 be a manned circumlunar mission.
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Online Lar

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Re: Unmanned Grey Dragon test flight before manned flight?
« Reply #6 on: 05/19/2017 02:07 PM »
SpaceX has already said there will be an unmanned flight as part of the certification process. It will be the very first flight of Dragon2. There is no way that SpaceX would do anything so dumb as to make the very first flight of Dragon2 be a manned circumlunar mission.

I vote no. However that's because I'm interpreting the poll as "will there be an unmanned flight AROUND THE MOON" rather than "will there be some unmanned test flight before the first manned one"  ... I kind of see the D2 sequence as

The FH test flight
Unmanned flight of D2
Unmanned flight of D2 that docks at ISS (these two may be combined)
Manned flight that docks at ISS (all three on F9)
Manned flight that goes around the moon (on FH)

But I may be wrong.

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Offline rockets4life97

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Re: Unmanned Grey Dragon test flight before manned flight?
« Reply #7 on: 05/19/2017 02:35 PM »
I kind of see the D2 sequence as

The FH test flight
Unmanned flight of D2
Unmanned flight of D2 that docks at ISS (these two may be combined)
Manned flight that docks at ISS (all three on F9)
Manned flight that goes around the moon (on FH)

But I may be wrong.

I agree. One thing I'd add is think they'll be at least 3 and probably more FH flights before they will put a crew on top.
It does raise an interesting question about whether FH and F9 are different enough that Dragon should fly with FH once before crew are on top.

Offline Negan

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Re: Unmanned Grey Dragon test flight before manned flight?
« Reply #8 on: 05/19/2017 04:31 PM »
I say no because I see no reason why it wouldn't already have been announced as part of the plan.

Edit: And my interpretation of the question is the same as Lar's.
« Last Edit: 05/19/2017 04:34 PM by Negan »

Offline ZachS09

There should be an unmanned test flight because, in my opinion, that's the logical path to take before putting men aboard the Gray Dragon.
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Online Lar

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Re: Unmanned Grey Dragon test flight before manned flight?
« Reply #10 on: 05/19/2017 05:46 PM »
There should be an unmanned test flight because, in my opinion, that's the logical path to take before putting men aboard the Gray Dragon.

See above. A test flight of WHAT? All the elements in the stack together?

If all of the following are true

FH test works (and maybe even slings a D1 around luna)
FH missions lofting birds work
F9 unmanned test of D2 to ISS works
F9 manned test of D2 to ISS works

is it really necessary to have an unmanned FH/D2 that slings the D2 around luna?  My answer is no, not needed. Elements were tested.

Every rocket is different somehow than all rockets that came before it.
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Online guckyfan

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Re: Unmanned Grey Dragon test flight before manned flight?
« Reply #11 on: 05/19/2017 07:07 PM »
I vote no. However that's because I'm interpreting the poll as "will there be an unmanned flight AROUND THE MOON" rather than "will there be some unmanned test flight before the first manned one"  ... I kind of see the D2 sequence as

The FH test flight
Unmanned flight of D2
Unmanned flight of D2 that docks at ISS (these two may be combined)
Manned flight that docks at ISS (all three on F9)
Manned flight that goes around the moon (on FH)

But I may be wrong.

That was my intended question. It is based on the assumption that qualification and the first crew flight to the ISS goes first, then the moon flight. Maybe that headline was short to express it unequivocally. My post, the first in the thread, where I explained why I vote no, should claify it somewhat.

Online Lar

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I vote no. However that's because I'm interpreting the poll as "will there be an unmanned flight AROUND THE MOON" rather than "will there be some unmanned test flight before the first manned one"  ... I kind of see the D2 sequence as

The FH test flight
Unmanned flight of D2
Unmanned flight of D2 that docks at ISS (these two may be combined)
Manned flight that docks at ISS (all three on F9)
Manned flight that goes around the moon (on FH)

But I may be wrong.

That was my intended question. It is based on the assumption that qualification and the first crew flight to the ISS goes first, then the moon flight. Maybe that headline was short to express it unequivocally. My post, the first in the thread, where I explained why I vote no, should claify it somewhat.

Thanks for the clarification, I edited the thread title and the poll question to reflect that.
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Online hop

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is it really necessary to have an unmanned FH/D2 that slings the D2 around luna?  My answer is no, not needed. Elements were tested.
Some elements significantly different from LEO flight: Cruise GNC, tracking, telemetry and thermal control, reentry GNC and TPS. Whether this requires a dedicated test flight is obviously suggestive, but putting crew on the first one is clearly higher risk.

I voted yes, but a BLEO test flight on a non-lunar trajectory could also cover a lot of the unproven territory.

edit:
Radiation environment is another potentially big one.
« Last Edit: 05/19/2017 08:13 PM by hop »

Offline TrevorMonty

I vote Yes. Dragon needs to proof its self BLEO and the heat shield.

Offline intrepidpursuit

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ISTM that they could test most of the BLEO functions in LEO - GNC, tracking, thermal control - even if you wouldn't otherwise need the enhanced capabilities in LEO. Long range communication and telemetry wouldn't get a full workout, but a loss of telemetry wouldn't not equal a loss of mission. As others have mentioned, there is enough TPS data from lots of LEO reentries that they can have a high level of confidence in lunar velocity performance.

Apollo tested the rocket and the spacecraft, but didn't send it to the moon before they put people on it. They added the LEM for the first time with people and made other configuration changes. I think we are in the same territory here.

NASA has no problem putting people on the first launch of anything they build. Assuming the first D2 missions have BLEO capabilities on board for testing, I think the risk level here is pretty low.

Offline rpapo

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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.
« Last Edit: 05/19/2017 09:10 PM by rpapo »
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Offline robert_d

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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 added the LEM for the first time with people and made other configuration changes. I think we are in the same territory here.


Not quite true: "LM-1 was built to make the first unmanned flight for propulsion systems testing, launched into low Earth orbit atop a Saturn IB. This was originally planned for April 1967, to be followed by the first manned flight later that year. But the LM's development problems had been underestimated, and LM-1's flight was delayed until January 22, 1968, as Apollo 5. At that time, LM-2 was held in reserve in case the LM-1 flight failed, which did not happen."


Offline Khadgars

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Even though the launch vehicle and spacecraft will have been tested, they will never have been tested in this environment.  I vote yes.

Offline DavidH

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Re: Unmanned Grey Dragon test flight before manned flight?
« Reply #19 on: 05/19/2017 10:08 PM »
There should be an unmanned test flight because, in my opinion, that's the logical path to take before putting men aboard the Gray Dragon.

See above. A test flight of WHAT? All the elements in the stack together?

If all of the following are true

FH test works (and maybe even slings a D1 around luna)
FH missions lofting birds work
F9 unmanned test of D2 to ISS works
F9 manned test of D2 to ISS works

is it really necessary to have an unmanned FH/D2 that slings the D2 around luna?  My answer is no, not needed. Elements were tested.

Every rocket is different somehow than all rockets that came before it.
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.
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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.

Online 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.

Online 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.
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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?
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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.

Online 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.
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Offline 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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