SpaceX COTS Demo 2/3 Updates (THREAD 2)

[baldusi]

It seems to me more like a panoramic head for a DLR camera.

[Space Pete]

if this was the COTS2/3 Dragon.

I doubt that it was - this looks like a lower fidelity mock-up than the C2/C3 Dragon.

[Comga]

Do we have enough information to estimate the phasing tolerance of Dragon?  That is how far out of phase can the ISS be at launch, and how quickly can the ISS be brought within that tolerance?  IIRC, one of the issues for carrying the Orbcomms was that deploying it would eat into the delta-V margin of the COTS-2/3 Dragon.

With 2 Soyuz, 3 Progress, 3 Dragon, 2 Cygnus, an HTV and an ATV in a year that's a lot of phasing.  HTV and ATV take a long time to get to the ISS so they must have huge ranges of allowed phasing.

I ask this because it would seem necessary to have an extended period after the preceding rendezvous to be able to include Dragon in the ISS VV schedule.  A casual perusal of anik's schedule points to the end of May as the next quiet period.

[Wyvern]

Here's some interesting news via twitter
"Kathryn Lueders of ISS program office shows complex chart of vehicles visiting ISS over next few years, "like a spaceport'"

"According to that chart, 1st SpaceX CRS mission slated for Aug 9 launch; 1st Orbital CRS mission launch Oct 2."
From Jeff Foust :https://twitter.com/#!/jeff_foust

This was from the FCC commercial space conference.

This would imply a second launch in early Oct, but interestingly it also implies an April 9th launch.  I wonder is the chart was made before the news that COTS 2/3 was going to be delayed to late April or if Spacex has changed their minds and are aiming for an early April launch again.

There is more news that may be relevant to the COTS 2/3 launch on Jeff fousts twitter stream but I don't want to create a giant post consisting entirely of tweets.

[Ben the Space Brit]

This would imply a second launch in early Oct, but interestingly it also implies an April 9th launch.  I wonder is the chart was made before the news that COTS 2/3 was going to be delayed to late April or if Spacex has changed their minds and are aiming for an early April launch again.

I understood that the most recent delay was due to ISS logistical and crew issues (too much activity around the station and/or not enough trained crew aboard).  Would there be any drawbacks or reasons not to launch the spacecraft and let it loiter in a stable orbit until the ISS is available for the berthing?

[mr. mark]

Wondering if SpaceX will still have vehicle integration and pad roll out as planned for testing in the remaining days of February? Musk commented on this several weeks ago. The plan was to integrate, do a pad test and then seperate the vehicle to continue capsule system tests.

[Namechange User]

Wondering if SpaceX will still have vehicle integration and pad roll out as planned for testing in the remaining days of February? Musk commented on this several weeks ago. The plan was to integrate, do a pad test and then seperate the vehicle to continue capsule system tests.

Unless this is required for some very specific reason, this would seem to be more work for the sake of more work at this point in time. 

Without knowing specifically what they are chasing, I see little reason at this point to integrate Dragon and Falcon (which is more than just attatching it to the top of the rocket) then taking it apart to do more tests on Dragon. 

You would likely lose more of the schedule for whatever really needs to be worked. 

[Kabloona]

This would imply a second launch in early Oct, but interestingly it also implies an April 9th launch.  I wonder is the chart was made before the news that COTS 2/3 was going to be delayed to late April or if Spacex has changed their minds and are aiming for an early April launch again.

I understood that the most recent delay was due to ISS logistical and crew issues (too much activity around the station and/or not enough trained crew aboard).  Would there be any drawbacks or reasons not to launch the spacecraft and let it loiter in a stable orbit until the ISS is available for the berthing?

More time on orbit = more time for something to go wrong. I can't imagine Musk wanting Dragon to spend more time on orbit than absolutely necessary for mission objectives on a maiden voyage.

[Kabloona]

Wondering if SpaceX will still have vehicle integration and pad roll out as planned for testing in the remaining days of February? Musk commented on this several weeks ago. The plan was to integrate, do a pad test and then seperate the vehicle to continue capsule system tests.

Unless this is required for some very specific reason, this would seem to be more work for the sake of more work at this point in time. 

Without knowing specifically what they are chasing, I see little reason at this point to integrate Dragon and Falcon (which is more than just attatching it to the top of the rocket) then taking it apart to do more tests on Dragon. 

You would likely lose more of the schedule for whatever really needs to be worked. 

From the Feb 3 SFN article by Stephen Clark, it sounds like what is being discussed is a wet dress rehearsal (WDR) that's part of the baseline launch ops plan, not an attempt to "chase" any recent issue, just like they've run WDRs on previous launches.

Only difference is, after this WDR, they demate Dragon before final pre-launch processing (fuel Dragon, load cargo, etc).

As for when they run the WDR, given the recent slips, you could argue that it's still prudent and desirable to run it as soon as it fits into the schedule. The whole point of the WDR is to (a) familiarize the launch team with the procedures, and (b) wring out the hardware, and the sooner you can accomplish both of those objectives, the better, especially if it gives you extra time to adress any technical issues that come up during WDR.

The less time you have between WDR and target launch date, the less time you have to work issues from WDR.

[kevin-rf]

Interesting blurb on flightglobal blaming the two month delay on a software test failure. A little short on details http://www.flightglobal.com/news/articles/software-test-failure-cited-as-cause-of-delay-to-falcon-9dragon-test-flight-368028/

[QuantumG]

Can't see anything wrong with this one. I'm amazed. Seems the only way to prevent Flight Global articles from including incorrect information, blatant errors in arithmetic or spelling errors is to keep them this short.

Oh wait, he did spell "criticised" with an "s".. but seeing as he's a Brit, you can't hold that against him. Especially seeing as he can spell NASA.

[Kabloona]

Interesting blurb on flightglobal blaming the two month delay on a software test failure. A little short on details http://www.flightglobal.com/news/articles/software-test-failure-cited-as-cause-of-delay-to-falcon-9dragon-test-flight-368028/

That's actually a lot less informative than the Feb 3 SFN article that has already been linked previously, but I'll link it again:

http://spaceflightnow.com/falcon9/003/120203update/

I don't know anything about software development, but those who do can probably read between the lines.

[iamlucky13]

Can't see anything wrong with this one. I'm amazed. Seems the only way to prevent Flight Global articles from including incorrect information, blatant errors in arithmetic or spelling errors is to keep them this short.

Oh wait, he did spell "criticised" with an "s".. but seeing as he's a Brit, you can't hold that against him. Especially seeing as he can spell NASA.

Their focus is aviation. They don't really have any dedicated space writers, as far as I know. I read Flightglobal regularly, but I go elsewhere for space-related articles.

[spacetraveler]

Interesting blurb on flightglobal blaming the two month delay on a software test failure. A little short on details http://www.flightglobal.com/news/articles/software-test-failure-cited-as-cause-of-delay-to-falcon-9dragon-test-flight-368028/

That's actually a lot less informative than the Feb 3 SFN article that has already been linked previously, but I'll link it again:

http://spaceflightnow.com/falcon9/003/120203update/

I don't know anything about software development, but those who do can probably read between the lines.

I'm a developer and this is how I read it.

Basically at this point in the workflow (earlier this month) the software would have already been completed and undergone a fairly extensive test program. Then, during some final simulations, they discovered a failure or defect. This means that not only was the software not ready for flight, but also that their testing regimen was insufficient because it did not identify this failure until it was encountered in the simulation in a build that was supposed to be production ready.

So now they've needed to go back and develop a much more robust testing workflow to make sure there are not any additional failures they've missed. This will naturally take more time as they first have to determine exactly what their test cases and strategy will be, and how much more testing needs to happen, then they have to conduct the testing.

After the testing, any additional defects identified will need to be corrected, then another round of testing (regression testing) to ensure that the fixes for these defects did not introduce additional defects. This is a nasty thing that can crop up sometimes. Occasionally you will apply a fix for one problem but this might change a behavior in your program that was relied upon for some other function and now that other function will not work as expected.

Finally, after the regression testing is passed and the software satisfies all required functions in runtime, it will be certified as ready.

[Antares]

SpaceX should consider themselves fortunate if software is the only concern at this stage of development.

[spacetraveler]

SpaceX should consider themselves fortunate if software is the only concern at this stage of development.

It's really no less of an issue than other things though. Software can just as easily lead to LOM as hardware.

[Robotbeat]

SpaceX should consider themselves fortunate if software is the only concern at this stage of development.

I don't think it's just software. As I recall, there was some concern about thermal management issues.

[ugordan]

SpaceX should consider themselves fortunate if software is the only concern at this stage of development.

I don't think it's just software. As I recall, there was some concern about thermal management issues.

And Merlin engine delamination.

[kevin-rf]

Actually in my mind

from the SpaceFlightNow

No significant problems arose during the Monte Carlo testing, but a simulation in mid-January exposed some concerns with the Dragon spacecraft's real-time operations tools.

Is quite different from FlightGlobal had said, referring to it as a test failure. Oddly, it looks like FlightGlobal has pulled the article.

Of course I live in a world where I constantly get marketing people referencing spelling errors in the data libraries the marketing group produces and ships with our product as "Software Bugs". (Between the lines that should tell what I think of the process the Marketing people follow) So I'm a little sensitive to the distinction.   

[Kabloona]

SpaceX should consider themselves fortunate if software is the only concern at this stage of development.

I don't think it's just software. As I recall, there was some concern about thermal management issues.

Yes, but Musk was quoted in the Feb 3 article as saying that the software was the long pole in the tent now. It sounds like the other issues are workable in less time than it's going to take to re-verify all the software.