Author Topic: SpaceX COTS Demo 2 Updates (Read 460383 times)

starsilk · « **Reply #160 on:** 04/20/2011 09:02 pm »

Quote from: Jason1701 on 04/20/2011 07:56 pm

I thought Nov/Dec was the earliest a combined flight could happen. If that's true, the statement is anticipating a non-combined test.

the statement says the Canadarm will be used to grapple it. I thought the plan for COTS-2 was to come close, but not that close...

mr. mark · « **Reply #161 on:** 04/20/2011 10:03 pm »

"the statement says the Canadarm will be used to grapple it. I thought the plan for COTS-2 was to come close, but not that close"...

Dragon most likely now will be a combined mission of COTS 2 and 3 meeting the objectives of "docking" with the station. Yes they may be bring up some supplies as early as next flight.

Jim · « **Reply #162 on:** 04/21/2011 12:50 am »

A press release is not a valid source

sdsds · « **Reply #163 on:** 04/21/2011 03:38 am »

McGregor test report:

Quote

Posted by: JR Location: Texas on Apr 20, 2011 at 07:30 AM

We live 30 miles away and saw it out the window. Thought it was a nuke! Then a minute later felt the rumble and heard the roar. Good grief! How do those that live closer stand it?

http://www.kwtx.com/ourtown/headlines/SpaceX_90_Second_Test_Could_Provide__120174669.html

starsilk · « **Reply #164 on:** 04/21/2011 04:48 am »

Quote from: mr. mark on 04/20/2011 10:03 pm

"the statement says the Canadarm will be used to grapple it. I thought the plan for COTS-2 was to come close, but not that close"...

Dragon most likely now will be a combined mission of COTS 2 and 3 meeting the objectives of "docking" with the station. Yes they may be bring up some supplies as early as next flight.

that was my point. if the press release is about the canadarm grappling Dragon, it *cannot* be discussing COTS-2. only COTS-3 (or combined 2+3).

but as Jim says, press releases have been known to be 'inaccurate'.

DaveH62 · « **Reply #165 on:** 04/21/2011 04:50 am »

Quote from: starsilk on 04/19/2011 05:11 pm

Quote from: ugordan on 04/19/2011 03:09 pm
No. All those tests were 9-engine, stage tests. Merlin 1d is probably at most at qualification testing stage at this point.

from the article:

Quote
SpaceX has performed multiple 10 and 90 second tests at the McGregor facility over the past month

why perform 'multiple 10 and 90 second tests .. over the past month' on a single stage?

and why would qualification tests not be done at McGregor? that's where they did (some of) the other qual tests..

I can imagine many issues to test on the same engine, most of which don't require firing nine concurrent engines:
1. Reuse, if they are going to reuse rockets, they'll need to test how many times an engine can be reused. Is there loss of power or capability after repeated use. What components are most subject to wear and tear. Can their design be changed to improve durability and reuse?
2. Tweaks to fuel and components. Same rocket, but you could modify a component and have weekly build tests as they test changes. Continual improvement methodology. Common in many industries, perhaps not for NASA.
3. Metrics: I am not one of the rockets scientists in the forum, but I expect getting quality metrics is a big challenge.

Apologies if I've misunderstood the question.

Antares · « **Reply #166 on:** 04/21/2011 11:37 am »

Occam's razor would say that it was because the preceding tests did not go as planned. Sacrilege among the amazing people, I know.

Dave G · « **Reply #167 on:** 04/21/2011 11:57 am »

Quote from: Jim on 04/19/2011 06:43 pm

Falcon 9 would not require increased testing for any specific COTS mission. The critical parts of a COTS mission is ISS approach.

Honest questions: Will all COTS/CRS flights use Merlin 1C? When will Falcon 9 start to use Merlin 1D? If SpaceX flies F9 w/1D for other customers first, will NASA be OK with using 1D?

In general, it seems to me that commercial companies will tend to be constantly tweaking the design to improve cost and performance, but this kind of goes against the idea of flight heritage. I'm wondering how this issue will play out.

Dave G · « **Reply #168 on:** 04/21/2011 12:14 pm »

Quote from: Antares on 04/21/2011 11:37 am

Occam's razor would say that it was because the preceding tests did not go as planned. Sacrilege among the amazing people, I know.

The Merlin 1D is a significant redesign from the 1C. 1D has many fewer parts, more performance, and is more amenable to mass production (up to 800 units per year). It makes sense that they would want a lot of test data on this new design. They may also be tweaking the design slightly with different tests to see what works best. I'd be surprised if they haven't scheduled for all this.

But with the FH announcement, I'd think initial 1D testing must have been pretty good, otherwise they wouldn't have been so confident on FH.

Nate_Trost · « **Reply #169 on:** 04/21/2011 02:06 pm »

The 90 second test runs were of the F9-003 stage, not Merlin 1D.

Robotbeat · « **Reply #170 on:** 04/21/2011 02:21 pm »

Quote from: Nate_Trost on 04/21/2011 02:06 pm

The 90 second test runs were of the F9-003 stage, not Merlin 1D.

And there is a zero chance that F9-003 includes Merlin 1D, right?

SpacexULA · « **Reply #171 on:** 04/21/2011 02:29 pm »

Quote from: Robotbeat on 04/21/2011 02:21 pm

Quote from: Nate_Trost on 04/21/2011 02:06 pm
The 90 second test runs were of the F9-003 stage, not Merlin 1D.
And there is a zero chance that F9-003 includes Merlin 1D, right?

They have not specified what engine is on that 1st stage.

Surely they are going to just place 1 Merlin 1D on a Falcon 1st stage with 8 other Merlin 1C for it's 1st launch, and put the 1D in the early off position on the rocket.

Is itpossible to have 8 Merlin 1C and 1 Merlin 1D on the same stage or is there not enough information?

kevin-rf · « **Reply #172 on:** 04/21/2011 02:51 pm »

Quote from: SpacexULA on 04/21/2011 02:29 pm

Surely they are going to just place 1 Merlin 1D on a Falcon 1st stage with 8 other Merlin 1C for it's 1st launch, and put the 1D in the early off position on the rocket.

Is itpossible to have 8 Merlin 1C and 1 Merlin 1D on the same stage or is there not enough information?

1. We do not have enough info.

2. You are suggesting mixing engines... Engines that have different startup, shutdown, and operating characteristics. Sounds like a headache waiting for a RUD. With out any insight, I would guess they would go all up when they fly the 1D.

Rockets are not the General Electric's 747-121 Engine Testbed N747GE!

bob the martian · « **Reply #173 on:** 04/21/2011 03:20 pm »

Quote from: Robotbeat on 04/21/2011 02:21 pm

Quote from: Nate_Trost on 04/21/2011 02:06 pm
The 90 second test runs were of the F9-003 stage, not Merlin 1D.
And there is a zero chance that F9-003 includes Merlin 1D, right?

Not a rocket scientist or engineer, but I can't imagine they'd mix engines with different performance characteristics on the same stage; seems like it would be a bit of a headache. It would either have to be 9 1Cs or 9 1Ds, and I didn't think the 1D was that far along in production yet.

Could be wrong, though. I usually am.

Chris Bergin · « **Reply #174 on:** 04/21/2011 05:28 pm »

Looking like a good chance NASA will approve C2 and C3 combined flights. We're seeing NASA documentation and memos (L2) giving dates and preps for readiness meeting dates in the event of approval.

NASA do like to prep things, but initial comments back claim it is within context to say it's looking positive.

Will aim to write it up after some asking around for additional notes and context.

robertross · « **Reply #175 on:** 04/21/2011 05:29 pm »

Quote from: Chris Bergin on 04/21/2011 05:28 pm

Looking like a good chance NASA will approve C2 and C3 combined. We're seeing NASA documentation and memos giving dates and preps for readiness meeting dates in the event of approval.

Will write it up after some asking around for context.

(Burns moment) Excellent.......

mr. mark · « **Reply #176 on:** 04/21/2011 05:30 pm »

Let's rock and roll................

ugordan · « **Reply #177 on:** 04/21/2011 05:36 pm »

Quote from: bob the martian on 04/21/2011 03:20 pm

It would either have to be 9 1Cs or 9 1Ds, and I didn't think the 1D was that far along in production yet.

Agree and my 2c would be that the M1d isn't in production yet, rather in a test phase to qualify the design (and any tweaks being done at this point).

I would bet there'll be a press release when the engine finishes development and that it won't happen before end of this year, but I've been wrong before.

Dave G · « **Reply #178 on:** 04/21/2011 09:29 pm »

Quote from: ugordan on 04/21/2011 05:36 pm

Agree and my 2c would be that the M1d isn't in production yet, rather in a test phase to qualify the design (and any tweaks being done at this point).

Yes, obviously, but the original question stands:
At what point (if ever) will the NASA COTS/CRS flights switch over to Falcon 9 with Merlin 1D?

COTS/CRS missions are scheduled through 2015. It seems probable Merlin 1D will be in production by then.

If SpaceX wants to use F9 w/1D for ISS resupply, will NASA let them? How much testing would NASA require for the new engine? If F9 w/1D flew for a commercial customer first, would NASA then follow suit on COTS/CRS with Merlin 1D?

ugordan · « **Reply #179 on:** 04/21/2011 09:35 pm »

My guess is M1d will replace M1c for all vehicles, even if derated for the current core propellant load. The SES contract requires them to fly M1d two times beforehand (probably at least one of those will be CRS) and the Falcon Heavy is virtually guaranteed to use only M1d. That puts the latter half of 2012/beginning of 2013 as the likely time for the switch.

I don't see a reason for NASA to prevent M1d on CRS flights, it's not the vehicle that goes near ISS, it's Dragon.