Author Topic: Dream Chaser suffers landing failure after first flight  (Read 69394 times)

Offline adrianwyard

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Re: Dream Chaser suffers landing failure after first flight
« Reply #20 on: 10/26/2013 10:41 PM »
Pure speculation: the landing gear and front skid got twanged around pretty hard when the DC was lowered to the ground - spinning clockwise under the Sky crane - after captive carry tests. Perhaps it was over-stressed in one of the helicopter landings this morning, and then failed during the first drop test.

See from 1:30 on in this video:

I'm guessing the rotation was caused by the SkyCrane's propwash...
« Last Edit: 10/26/2013 10:44 PM by adrianwyard »

Offline renclod

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Re: Dream Chaser suffers landing failure after first flight
« Reply #21 on: 10/26/2013 10:57 PM »
... perhaps even an uneven touchdown on the mains ...

Very uneven - the article says "left landing gear (failure to deploy)"


Offline NovaSilisko

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Re: Dream Chaser suffers landing failure after first flight
« Reply #22 on: 10/26/2013 11:15 PM »
The gear is a totally different design (and deployment mechanism) from what will actually be on the spacecraft. I'm not too worried. The biggest roadblock here is repairing (or rebuilding) the ETA, and dealing with potential political fallout ("what do you mean something what wrong? that's not what we pay you for!")

Offline mr. mark

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Re: Dream Chaser suffers landing failure after first flight
« Reply #23 on: 10/26/2013 11:19 PM »
This may have been the last flight... just saying. Not sure if the the program survives down select. We will have to see.

Online Lee Jay

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Re: Dream Chaser suffers landing failure after first flight
« Reply #24 on: 10/26/2013 11:22 PM »
If SNC loses in down select due to failure of a non-flight component then I'll lose all respect for the selectors and the selection process.  Recent history has shown both to be thoughtful and rational.

Offline mr. mark

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Re: Dream Chaser suffers landing failure after first flight
« Reply #25 on: 10/26/2013 11:26 PM »
There will be pressure from outside the program. It's not just about engineering, everyone knows that. There's two other competitors. Boeing has conducted a successful parachute droptest and SpaceX has flown three cargo Dragons to the ISS all of which came home safely. The pressure is mounting and down selection is near.
« Last Edit: 10/26/2013 11:29 PM by mr. mark »

Online Lee Jay

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Re: Dream Chaser suffers landing failure after first flight
« Reply #26 on: 10/26/2013 11:35 PM »
The choice should be based on what's best for the program over the long term and DC has significant advantages over the other vehicles in this respect.  This vehicle was due to be retired in favor of the FTA at some point.  Now they may just have to use that vehicle for more of the flight testing if this one can't be quickly returned to flight status.

Offline Rocket Science

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Re: Dream Chaser suffers landing failure after first flight
« Reply #27 on: 10/26/2013 11:42 PM »
The Shuttle program chose the simplicity of gravity for gear deploy and for good reason. This could be a take away lesson from this unfortunate turn of events...
"The laws of physics are unforgiving"

Offline joek

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Re: Dream Chaser suffers landing failure after first flight
« Reply #28 on: 10/26/2013 11:47 PM »
If SNC loses in down select due to failure of a non-flight component then I'll lose all respect for the selectors and the selection process.  Recent history has shown both to be thoughtful and rational.

I think it would have more to do with how much of a setback this represents to SNC's timeline.  SNC had a bad day.  They'll make it up or they won't.  If they do it shouldn't matter.  If they don't and they're not ready when the clock chimes, that does not necessarily reflect badly on the selection process. 

Online Lee Jay

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Re: Dream Chaser suffers landing failure after first flight
« Reply #29 on: 10/26/2013 11:49 PM »
Don't forget that this deployment mechanism has nothing to do with the flight mechanism.  Also Shuttle gear could fail to deploy and had backup pyro deploy for such a circumstance.

Offline Lars_J

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Re: Dream Chaser suffers landing failure after first flight
« Reply #30 on: 10/26/2013 11:54 PM »

Don't forget that this deployment mechanism has nothing to do with the flight mechanism.  Also Shuttle gear could fail to deploy and had backup pyro deploy for such a circumstance.

Why would they have flown with such a different leg deployment mechanism compared to what they intend to use?


Online Lee Jay

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Re: Dream Chaser suffers landing failure after first flight
« Reply #32 on: 10/26/2013 11:56 PM »
Because the flight mechanism wasn't ready when this vehicle was built.  So they borrowed an existing system.

Online Lee Jay

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Re: Dream Chaser suffers landing failure after first flight
« Reply #33 on: 10/27/2013 12:01 AM »
Carefully worded release.

http://www.sncspace.com/press_more_info.php?id=369

The focus is correct, however.

Good release.  Basically it flew perfectly to an on-glideslope on-centerline touchdown.  Probably would have been a good rollout as well.  This means they have a good handle on at least some of the low-speed aerodynamic behavior.  Supersonic and hypersonic performance are another issue.

Offline ChrisWilson68

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Re: Dream Chaser suffers landing failure after first flight
« Reply #34 on: 10/27/2013 12:05 AM »
If SNC loses in down select due to failure of a non-flight component then I'll lose all respect for the selectors and the selection process.  Recent history has shown both to be thoughtful and rational.

Just because it's not a flight component doesn't mean it shouldn't legitimately be held as a point against SNC.  SNC was responsible for making sure the landing gear on the ETA worked properly.  They failed at that.  It's legitimate to consider that error in the down select process.

A landing gear failure is a pretty bad, basic mistake.  Lots of companies develop aircraft and test fly them without having landing gear failures.  It calls into question SNC's management and oversight practices.

This one mistake by SNC isn't the only factor of course.  It will have to be weighed against the successes and failures of the other two contenders, as well as other considerations such as the predicted long-term projected costs and financial stability of the contenders, commonality of components with non-crew systems giving greater operational testing over time, etc.

Offline ChrisWilson68

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Re: Dream Chaser suffers landing failure after first flight
« Reply #35 on: 10/27/2013 12:09 AM »
Carefully worded release.

http://www.sncspace.com/press_more_info.php?id=369

The focus is correct, however.

From the press release:

Quote
11:10 a.m. Pacific Standard Time

Actually, it's Pacific Daylight Time.

Offline Rocket Science

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Re: Dream Chaser suffers landing failure after first flight
« Reply #36 on: 10/27/2013 12:11 AM »
The selection of the F-5 gear was an artifact from heritage of the HL-20...
"The laws of physics are unforgiving"

Offline ChrisWilson68

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Re: Dream Chaser suffers landing failure after first flight
« Reply #37 on: 10/27/2013 12:48 AM »
The real damage to the Dream Chaser program is the schedule slip.  It sounds like the ETA will at best require very substantial repairs and at worst be a complete write-off.  That likely means many months of delay in the program.  Which means that by the time the down select decision is made, Dream Chaser will have less of its testing program done and hence more unretired risk and a lower technology readiness level.  Dream Chaser was already looking like a long shot for the down select, and this makes it look even less likely Dream Chaser can be selected for the next phase of NASA funding.

So, this crash, while it might have been just a temporary problem in a program with an already-assured future, might mean the end of Dream Chaser given its tenuous situation already.

Offline a_langwich

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Re: Dream Chaser suffers landing failure after first flight
« Reply #38 on: 10/27/2013 01:17 AM »
If SNC loses in down select due to failure of a non-flight component then I'll lose all respect for the selectors and the selection process.  Recent history has shown both to be thoughtful and rational.

I think it would have more to do with how much of a setback this represents to SNC's timeline.  SNC had a bad day.  They'll make it up or they won't.  If they do it shouldn't matter.  If they don't and they're not ready when the clock chimes, that does not necessarily reflect badly on the selection process. 

Agreed.  In addition, the winged lifting body is a more ambitious project than a capsule, so they had more engineering work to tackle than SpaceX or Boeing.  And they probably started a little behind SpaceX and Boeing; SpaceX had built Dragon and has been flying and recovering it, and Boeing had fairly extensive experience with capsules and capsule designs they could re-use.  And, to my perception, they have expended less money per unit time than SpaceX or Boeing, when the above two factors would require more money spent faster to stay even or catch up.

Still, the clock hasn't yet chimed.  We'll see what measures are needed to recover.

P.S.  You could make a drinking game on how many times the shuttle is mentioned on any article about DreamChaser, or any quote from SNC about DC.  The references get a bit thick sometimes.  Those references are a good excuse to stop talking about DC and wax nostalgic about the good old shuttle, but really the focus needs to stay on Dream Chaser, what it has actually accomplished and how far it still needs to go.

Offline sdsds

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Re: Dream Chaser suffers landing failure after first flight
« Reply #39 on: 10/27/2013 01:18 AM »
The upside is that this gives senior SNC leadership an opportunity to "step up" and show they have "the right stuff." If on the other hand they don't really have the right stuff, the project would have been skating on very thin ice indeed, regardless of the outcome of this (and other) test flights.
-- sdsds --

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