SpaceX COTS Demo 1 Updates

[blazotron]

It's surprising how many people here seem to think SpaceX wouldn't have done analyses on performance, trajectory, stability and control, thermal issues, structural issues, etc.  Much of the computation and analysis infrastructure (models, meshes, etc) is presumably already in place or easily modified from analyses that were certainly performed for the nominal nozzle configuration.  Based on these results, either new computations could be performed or where large margins exist perhaps scaling or estimates are enough to show that the new configuration is well within safe limits.  No doubt a substantial amount of thermal analysis was done for the second stage roll anomaly investigation.

People seem to forget that while the company has a substantial fraction of (talented) young employees, it also a significant number of experts from Boeing, NGC, TRW, Rocketdyne, Aerojet, NASA, etc, very much like NASA 50 years ago.  It's not like these people just forgot how "things are done" when they left their respective positions to go to SpaceX.  It's likely that they decided that wanted to do some things differently, but you can't get a Falcon 9 to orbit without a great deal of analysis and test.  None of this means they won't get things wrong in the future (they can and have in the past), perhaps even this very issue, but it would make very little sense to delay the launch for weeks to perform additional testing on Dragon and then blindly cut off the end of the nozzle extension unless they were very confident of the root cause and the high probability of success in the new configuration. 

[Antares]

Blazo, I will be rightly impressed if SpaceX can put intuition back in its deserved place in space (systems?) engineering.  I'm just saying there are lots of forces (or maybe just inertia) who think it doesn't work.  I hope (since I lack the evidence to claim) that SpaceX knows its system well enough that its intuition is infallible.

Edit: and still, people are claiming hopes and beliefs on things for which they lack evidence.  I shiver at that.

[jongoff]

I think, though, that you'd have to agree that the only thing worse than having too many systems engineers is... not having enough. ??

I think so...not sure.  If you take small enough steps, and keep the cost of failure or rework low enough though you can compensate a lot more for the latter.  So long as you have other engineers who are good in their technical areas.  To a poin.....yeah I don't really know.

~Jon

[jimvela]

What's going here? Not all of the pictures (different days, different times of day?) show this umbilical like this, but what gives?

Nobody is running with this?  Something is disconnected.
http://forum.nasaspaceflight.com/index.php?topic=22041.msg667684#msg667684

The picture looks to me like that item is ducting for conditioned air being fed to the dragon.  It seems really odd that the air supply would be designed to separate in the middle like that instead of pulling off at the dragon.

I can't imagine that the dragon side of that connection is designed to come off early in flight like a thruster cover... 

It also wouldn't make sense to have it as just an unused mock up as I'd assume that the dragon would actually need conditioned air...

Almost reminds me of the beat up spiral air ducting that is sometimes seen at an [unnamed all-solid launch vehicle] facility...

[butters]

A bit of on-orbit mission summary from SFN:

Engineers have programmed portions of the Dragon's rendezvous sequence with the space station into the craft's computer for this mission. The flight testing will verify the capsule's ability to accomplish tightly-choreographed maneuvers.

So the mission profile is basically to run through the CRS rendezvous sequence, skipping the initial phase angle "chase" for time/power considerations. Except they'll be practicing these maneuvers without the trunk they'll have on the real CRS missions.

[iamlucky13]

Yes, the thermal effect was my first concern as well, but I can't imagine that their analysis did NOT go as far as heat transfer, as you say. THAT would definitely be "systems engineering" failure, IMO. A previous post speculated that they've already done the analysis for vacuum without the extension (which they've said they don't "need"), which would represent a more severe heating case, and therefore they've already bounded the problem. That would seem to make sense, and would explain why they're apparently comfortable going this route.

Ok, I should have given a little more thought to my last comment - they may have a computer model ready to run that allows them to easily adjust the nozzle dimensions.

Typically such up such an analysis is more work at the start, and less work if you have to reiterate.

But my initial instinct, given that the primary design criteria for the nozzle is expansion of the flow, not thermal factors is not to assume that a ready model exists to run. Perhaps it does, perhaps it doesn't, but given an apparent defect made it through QA and integration and how fast things seem to be happening right now, I'm not sure what to think about how much initiative their engineers take in identifying and following up on potential failure scenarios.

By the way, I'm not saying I think it's a problem. I don't, although I also can't entirely dismiss it.

7 hours...

[Skyrocket]

Does anyone know, which Cubesats will be launched on this mission?

[Ben the Space Brit]

I suppose my concern is that SpaceX is feeling a 'pressure to launch', given the imminence of shuttle retirement and the increasingly critical role CRS seems likely to play in this post-Constellation era.

I'm sure that NASA would not have authorised them to go if they weren't sure that the vehicle wouldn't fly safely.  That said, what SpaceX needs, and thus far has had very little of, is a nominal flight where everything works acceptably.  Until that happens, NewSpace commercial is going to continue to be perceived by the politicians as a bunch of enthusiastic, well-funded amateurs who cannot be trusted with America's space program.

The other day, I was watching some early Atlas flights on YouTube (both ICBM tests and Atlas/Agena launches).  Even the big guys have had some hard times, split nozzles and pretty pyrotechnic aborts at T+1 minute.  However, it's been a long time since then and the modern American public has forgotten that getting rocket designs, manufacturing and quality control right is a slow, error-strewn process.  My concern is that if SpaceX does not get up to speed quickly, political and public willingness to give them the needed time might run out.

[joshcryer]

I hope they're feeling the pressure. Once STS retires for good, they will be largest carrier of logistics to and from the ISS. Without them the whole ISS project may be in jeopardy. As a taxpayer I want them to know that if they screw this up they screw up America's astronaut program for years.

[Mapperuo]

NASA TV has live shot of the rocket on the Media Channel beginning in an hour, Then at 1:55pm GMT live coverage of the launch on all channels for those interested.

Should be a bit better than the Space X page. 

[docmordrid]

http://www.spaceflightnow.com/falcon9/002/status.html

0930 GMT (4:30 a.m. EST)

After trimming away a cracked portion of an engine nozzle, SpaceX is readying its Falcon 9 rocket for a launch opportunity this morning.

The launch window opens at 9 a.m. EST (1400 GMT), but SpaceX will likely target liftoff three minutes later at 9:03 a.m. EST (1403 GMT).
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If SpaceX is on track for the 9:03 a.m. launch opportunity, fueling operations are expected to begin after 7 a.m. EST (1200 GMT) today.

[FinalFrontier]

http://www.spaceflightnow.com/falcon9/002/status.html

0930 GMT (4:30 a.m. EST)

After trimming away a cracked portion of an engine nozzle, SpaceX is readying its Falcon 9 rocket for a launch opportunity this morning.

The launch window opens at 9 a.m. EST (1400 GMT), but SpaceX will likely target liftoff three minutes later at 9:03 a.m. EST (1403 GMT).
>
>
If SpaceX is on track for the 9:03 a.m. launch opportunity, fueling operations are expected to begin after 7 a.m. EST (1200 GMT) today.

will return at 8 then

[Kabloona]

the modern American public has forgotten that getting rocket designs, manufacturing and quality control right is a slow, error-strewn process. 

...and Elon is trying to remind them:

http://spaceflightnow.com/falcon9/002/101208risk/

[MP99]

I'm finding myself pretty worried that this issue has escaped until this late in the process. What's to say there isn't another issue that's escaped QA, but where it's not subject to a final visual check? This seems comparable to the intertank issue on STS-133, and ISTM that's not going to fly until we understand what caused it sufficiently to be sure that it will fly safely. (But I guess the alternative is to tear the whole Falcon apart and check it over. [**] )

If SpaceX could replace the nozzle and still fly on Friday, why would you not do that rather than take an unnecessary risk? Imagine if the nozzle fails! I also wonder if there are any failure modes where they could be left wondering if a nozzle issue contributed.



I did wonder whether lopping 4' off the Mvac nozzle would make it the same size as the first stage nozzle, as there would then be some analysis that might be relevant (though not sure if this nozzle would have the same profile as 1st stage?). But I think the first stage nozzle looks smaller than 5'?

cheers, Martin

[**] Has anyone ever done that - built a rocket, put if through WDR and/or static fire, then tear it down and see how the structure coped?

[jabe]

good find..thanks for link..lets hope no one watches it so server doesn't get swamped

[MP99]

Y'all take a lot of things on faith, assuming SpaceX has analyzed this case.

It's hard to conceive that they would fly without analysing, but surprising that they could undertake a comprehensive analysis in such a short time. Jeez, that's a scary thought.

cheers, Martin

[Skyrocket]

Concerning the cubesats in the trunk:

Apparently there are 5 cubesat on this mission:

* 2 cubesats (3U) of NRO's Colony-1 program
* 2 cubesats of the Los Alamos National Laboratory
* 1 cubesat of the US Army - this one is likely the first of eight SMDC-ONE satellites.

http://www.spacenews.com/military/100408-nro-taps-boeing-next-cubesats.html

[docmordrid]

NASA TV (cable) just flashed a promo for its COTS-1 coverage, listing it as "next." The current programming block ends at 7:00 AM EST, so perhaps the're going to cover the fueling on.  We'll see.

[Chris Bergin]

Not sure how people missed it, but the live coverage thread is here:
http://forum.nasaspaceflight.com/index.php?topic=23516.0

[joshcryer]

Chris, I am pretty sure we're respecting the "updates only" request. There were a lot of random discussions in this thread, and I personally am going to try to reduce the noise for people who are trying to get real, substantiative updates. I know I always come to NSF for live play-by-plays, and I think you got a good thing going there. (I bet traffic spikes like crazy during these events.)