SpaceX COTS Demo 2/3 Updates (THREAD 2)

[Robotbeat]

So this F9/Dragon could have been able to launch as early as November as far as the vehicle was concerned?

Based on what?  They still might not be finished testing.

You'll never know. Big difference between gov't orgs and private industry. Private industry always plays "schedule chicken" as I like to call it. See who blinks first. Elon said they were ready to fly in November when, of course, the Soyuz failure meant there was no chance they would be allowed to. So were they really ready? My guess is no. Now that there's a real launch date, you'll see things get adjusted to make it. For example, Orbcomm got dropped. My industry is similar in at least that regard. Always interesting to see the features on a chip at PDR versus what gets axed as the tapeout date approaches. It's always something, and always more than one thing. Of course, we'd never advertise that. No, no. Our stuff is perfect. Always.

Good post.

[simonbp]

Software wasn't really ready, though.

It never is. That's called job security.

[Lars_J]

Private industry always plays "schedule chicken" as I like to call it. See who blinks first. Elon said they were ready to fly in November when, of course, the Soyuz failure meant there was no chance they would be allowed to. So were they really ready? My guess is no.

Everyone does it, not just "private industry". NASA did it with the early ISS construction. In public they were concerned about Russian delays in launching the service module - but behind the scenes they were very thankful for the breathing room, as the US Lab module was far from ready to launch. In the end the delay ended up working out well for NASA, and the lab module was delivered during the Expedition 1 stay.

[Antares]

So this F9/Dragon could have been able to launch as early as November as far as the vehicle was concerned?

Based on what?  They still might not be finished testing.

You'll never know.

Good post.

No.  On NSF many of us do know, but commercial contractors are protected by proprietary restrictions that we weren't subject to under Shuttle.

[Robotbeat]

So this F9/Dragon could have been able to launch as early as November as far as the vehicle was concerned?

Based on what?  They still might not be finished testing.

You'll never know.

Good post.

No.  On NSF many of us do know, but commercial contractors are protected by proprietary restrictions that we weren't subject to under Shuttle.

I was referring to the rest of the post about playing "schedule chicken."

[2552]

Update:

Photo Update: Falcon 9 in the hangar at Cape Canaveral. Getting ready to make history. http://pic.twitter.com/tKynEKwc

[Lars_J]

A new angle! (at least better than the same pic that has been twittered many times)

[wolfpack]

So this F9/Dragon could have been able to launch as early as November as far as the vehicle was concerned?

Based on what?  They still might not be finished testing.

You'll never know.

Good post.

No.  On NSF many of us do know, but commercial contractors are protected by proprietary restrictions that we weren't subject to under Shuttle.

I'm sure that you guys know. Don't spill any beans here, everyone needs a job these days!

Interesting work you guys do, makes me wish sometimes I had done an aeronautical engineering degree vs an electrical one. Too late for me now, I've had kids and my brain doesn't work right anymore!

[Antares]

Way more electricals and mechanicals than aero/astro folks.  It sounds like you'd make a great civil servant

[corrodedNut]

In the photo, we can see about half of each pontoon.  I see six openings.  Four appear to be for access to the latches that hold the pontoon to the trunk during launch.  Anyone have any information (or guesses) as to the purposes of the access ports on the upper left and lower right?

There are accesses for each separation fitting, see photo of old "trunk", each one connects the trunk to the Dragon with a pyrotechnic frangible nut. They need to access these through the pontoons now that they are in the way.

As for the Trunk-to-2nd stage separation system, these yet to be flown "release mechanisms" will also need accesses. If they are similar to the 2nd stage-to-interstage "pneumatically actuated mechanical collets" then there could be as many as nine, but it appears that there are only six.

You can see that the trunk has evolved from carbon composite to an all aluminium design, but the new pontoons are still composite.

The 2nd stage design has evolved as well, it's now longer (presumably to accommodate these new "release mechanisms") and may or may not have boat-tail fairings to fit onto the new pontoons. So far they've only been seen as part of the test article in the bottom photo.

[Comga]

The old photo is a good illustration of how the ports on the pontoons line up for access to the 2nd-stage-to-trunk and trunk-to-Dragon attach and release mechanisms.

However, the "boattail" in that photo is odd.  It is much wider than the pontoons, and not lined up with either.  It doesn't appear to be the equivalent of something that would fly.  However, the bottom of the pontoons appear open, although one would expect them to close off the volumes.

[corrodedNut]

It's hard to see, but it doesn't look like there is sufficient room for the pontoon covers to pivot away from the PICA-X heatshield.  That implies that these covers are ejected.   Has anyone seen this event on a timeline?  There was a CRS CGI video somewhere that showed the solar panels deploying, but it predates this configuration.

In every animation/simulation that shows this, the pontoons are jettisoned post Dragon-2nd stage sep. Assuming that Dragon is directly injected like the last flight, to me this seems like unnecessary orbital debris. At the very least it's a mass penalty. Why not jettison them at the same time as the nose cap? Of course, these animations may not be accurate.

[corrodedNut]

However, the "boattail" in that photo is odd.  It is much wider than the pontoons, and not lined up with either.  It doesn't appear to be the equivalent of something that would fly.  However, the bottom of the pontoons appear open, although one would expect them to close off the volumes.

I think that the separation has already occurred in that photo, and that the trunk/pontoon article has rotated and or swayed out of alignment while suspended from the counter balance cables. SpaceX has released video of all previous separation tests, just not this one. Too bad, then we'd know. I guess we'll have to wait for a photo of the integrated vehicle.

In any case, the "boat tails" seem to be missing in this photo of the Flight3 2nd stage.

[Robotbeat]

Is the aluminum trunk likely cheaper (assuming it was as simple as the previous one)? It's most probably a little heavier. I doubt they had much choice, since aluminum is generally easier to use when you've got lots of details and odd shapes you need stuff to be in (carbon fiber isn't "black aluminum").

[MikeMelga]

Aluminium is certainly heavier than a CF piece. Carbon fiber has several problems, namely cost, delamination, construction time and expertise, etc.

[apace]

Aluminium is certainly heavier than a CF piece. Carbon fiber has several problems, namely cost, delamination, construction time and expertise, etc.

As SpaceX is currently looking for composite and carbon specialists to hire, I think they will change to carbon a soon as they have the people and the experience to do it.

[Jim]

Aluminium is certainly heavier than a CF piece. Carbon fiber has several problems, namely cost, delamination, construction time and expertise, etc.

Not always, it depends on how many items are bonded to it.

[baldusi]

Aluminium is certainly heavier than a CF piece. Carbon fiber has several problems, namely cost, delamination, construction time and expertise, etc.

Not always, it depends on how many items are bonded to it.

I've read a paper on Orion's composite pressure vessel test. And the result was that the binding constraint was not the structural strength, but the resistance to integration damage. So it ended weighting the same than the aluminum one, yet cost a lot more and made it very difficult to integrate and perforate. So composite has its places, but the inter stage might or might not be a part. And the Dragon pressure vessel, most probably won't.

[manboy]

Aluminium is certainly heavier than a CF piece. Carbon fiber has several problems, namely cost, delamination, construction time and expertise, etc.

Not always, it depends on how many items are bonded to it.

I've read a paper on Orion's composite pressure vessel test. And the result was that the binding constraint was not the structural strength, but the resistance to integration damage. So it ended weighting the same than the aluminum one, yet cost a lot more and made it very difficult to integrate and perforate. So composite has its places, but the inter stage might or might not be a part. And the Dragon pressure vessel, most probably won't.

Is this that paper?
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110020665_2011021823.pdf

[baldusi]

Aluminium is certainly heavier than a CF piece. Carbon fiber has several problems, namely cost, delamination, construction time and expertise, etc.

Not always, it depends on how many items are bonded to it.

I've read a paper on Orion's composite pressure vessel test. And the result was that the binding constraint was not the structural strength, but the resistance to integration damage. So it ended weighting the same than the aluminum one, yet cost a lot more and made it very difficult to integrate and perforate. So composite has its places, but the inter stage might or might not be a part. And the Dragon pressure vessel, most probably won't.

Is this that paper?
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110020665_2011021823.pdf

Exactly. Red the part previous to the conclusions (small agile teams can do things cheaper and faster, I kid you not!).