Author Topic: SCRUB: SpaceX - Falcon I (Mk.II) NET March 19 (Read 178702 times)

R&R · « **Reply #160 on:** 01/23/2007 11:04 pm »

Anyone know anything about testing of the second stage? like post build tests at the factory? integrated tests at the factory or Kwaj?

I'm curious because I wonder if they found the problem with the only testing they do e.g. countdown. It's not likely they test the engine movement horizontal and I don't see anything obvious on the website to indicate how they test it. I hope they are not so naive as to believe in a ship and shoot approach.

edkyle99 · « **Reply #161 on:** 01/24/2007 05:28 pm »

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R&R - 23/1/2007 6:04 PM

Anyone know anything about testing of the second stage? like post build tests at the factory? integrated tests at the factory or Kwaj?

I'm curious because I wonder if they found the problem with the only testing they do e.g. countdown. It's not likely they test the engine movement horizontal and I don't see anything obvious on the website to indicate how they test it. I hope they are not so naive as to believe in a ship and shoot approach.

SpaceX did a wet dress rehearsal with this launch vehicle a week or two before the static test countdown. I don't know if that test included slewing the engines.

EDIT: Now I suspect that the wet dress probably would have slewed the engines, based on the following statement on the SpaceX web site (emphasis mine):

"Following the FRR, the Falcon 1 was rolled out to the pad and we completed our wet dress rehearsal, which is a full countdown that holds approximately one minute before T-0. "

- Ed Kyle

BarryKirk · « **Reply #162 on:** 01/25/2007 11:45 am »

When the upper stage is stacked on top of the lower stage, can it's engine still be slewed?

Or is it constrained by structural elements that are discarded during the staging process?

Jim · « **Reply #163 on:** 01/25/2007 01:22 pm »

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BarryKirk - 25/1/2007 7:45 AM

When the upper stage is stacked on top of the lower stage, can it's engine still be slewed?

Or is it constrained by structural elements that are discarded during the staging process?

If it can't then it is a bad design. Most LV's slew their engines late in the count

BarryKirk · « **Reply #164 on:** 01/25/2007 04:49 pm »

I never knew that. That is a nice tidbit of info. Thanks.

aero313 · « **Reply #165 on:** 01/25/2007 06:48 pm »

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Jim - 25/1/2007 9:22 AM

Most LV's slew their engines late in the count

You're telling us that the Delta II has adequate clearance in the "beercan" to slew the Stage 2 nozzle pre-launch? I'd be surprised. Also, many launch vehicles (certainly solid propellant ones with which I'm familar) use thermal batteries to power electromechanical actuators and thus cannot slew the nozzles until the batteries are activated just prior to staging.

Yes, every LV exercises TVC actuators during I&T, and all perform some sort of nozzle sweep on the first stage prior to liftoff, but many upper stages with large expansion ratio nozzles cannot physically slew the nozzles prior to staging. I'm sure the Centaur has that capability, but upper stages with large expansion ratio nozzles typically do not.

Jim · « **Reply #166 on:** 01/25/2007 07:29 pm »

Delta II & IV do it every countdown. I said most.

spacedreams · « **Reply #167 on:** 01/25/2007 07:43 pm »

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aero313 - 25/1/2007 11:48 AM but many upper stages with large expansion ratio nozzles cannot physically slew the nozzles prior to staging. I'm sure the Centaur has that capability, but upper stages with large expansion ratio nozzles typically do not.

We studied the RL-10 (Delta IV upper stage engine) in a combustion class I took and it has a nozzle that is retracted on launch and extended after separation so they have a little more wiggle room in the "can". It is actually a pretty amazing little engine with regen cooling and the works.

reubenb · « **Reply #168 on:** 01/25/2007 08:52 pm »

There's a new update on the SpaceX site: http://www.spacex.com/updates.php
Due to an "excess of caution" they did not go through with the static fire and are postponing until mid to late February.

HIP2BSQRE · « **Reply #169 on:** 01/25/2007 09:40 pm »

rather safe than lose the rocket and maybe a year getting back to this point again

Nate_Trost · « **Reply #170 on:** 01/25/2007 10:44 pm »

I'm a bit curious if they were *starting* to do a static fire test in the days after discovery of the second stage anomaly and scrubbed it due to some countdown issue causing them to pull it off the pad, or if the second stage issue was enough in and of itself.

Comga · « **Reply #171 on:** 01/25/2007 11:18 pm »

January 25, 2007: DemoFlight 2 Launch Update

In an excess of caution, we decided not to proceed with the static fire this month. The vehicle is now back in the hangar, where the stages are being demated for careful inspection.

The static fire and launch window is now mid to late February, due to Kwaj having to configure for an incoming Minuteman and then reconfigure back to handling a Falcon launch. During this downtime, we will take the opportunity to go over every inch of the rocket with a microscope again.

As Andy Grove said, "Only the Paranoid Survive".

---Elon

R&R · « **Reply #172 on:** 01/28/2007 02:52 pm »

Too bad their design for the rocket and pad force them to take apart the stages. I'm sure part of this is that the rocket is very small but from all the pictures I can find I don't see any large doors on the interstage to look through. It's basic engineering principle to maintain configuration to the greatest extent possible when troubleshooting a problem. As soon as they disconnected and layed it down they lost that.

Delta and Atlas both have the access to do inspections without taking things apart and Delta's with their MST's and Atlas with it's quick return to the VIF don't have to go back to horizontal. Plus they can do better testing to repeat and better understand the problem.

As it is now SpaceX will have the same kind of crank it vertical and shoot design for the F9. Hopefully they are learning a lesson or already have it in mind to provide better access into the interstage and maybe a re-think about access on the Pad.

aero313 · « **Reply #173 on:** 01/28/2007 03:37 pm »

Isn't it ironic that every space launch venture that criticizes the traditional way of doing business and claims to be "smarter" eventually finds out that just maybe the traditional launch systems do things for a reason and not just to arbitrarily make their rockets more expensive...

Sort of like how as you get older, your parents don't seen as stupid as they did when you were a teenager.

dreamweaver · « **Reply #174 on:** 01/31/2007 03:50 am »

Keep in mind that there are not insignificant costs associated with maintaining the launch facilities that provide vertical access.

Delta Manager · « **Reply #175 on:** 01/31/2007 04:00 am »

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aero313 - 28/1/2007 10:37 AM

Isn't it ironic that every space launch venture that criticizes the traditional way of doing business and claims to be "smarter" eventually finds out that just maybe the traditional launch systems do things for a reason and not just to arbitrarily make their rockets more expensive...

Sort of like how as you get older, your parents don't seen as stupid as they did when you were a teenager.

I see the Orbital guys are still hanging around this SpaceX section

aero313 · « **Reply #176 on:** 01/31/2007 03:38 pm »

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Delta Manager - 30/1/2007 12:00 AM
I see the Orbital guys are still hanging around this SpaceX section

That's EX-Orbital by a lot of years, thank you very much.

braddock · « **Reply #177 on:** 01/31/2007 04:00 pm »

They're keeping us honest.

Cretan126 · « **Reply #178 on:** 02/05/2007 04:03 pm »

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aero313 - 28/1/2007 9:37 AM Isn't it ironic that every space launch venture that criticizes the traditional way of doing business and claims to be "smarter" eventually finds out that just maybe the traditional launch systems do things for a reason and not just to arbitrarily make their rockets more expensive... Sort of like how as you get older, your parents don't seen as stupid as they did when you were a teenager.

So, Aero, where in the maturing process do you put SpaceX now? I'm going for High School Junior: ~ 16 years. Maybe they'll get a drivers license if they can pass the test in February.

edkyle99 · « **Reply #179 on:** 02/06/2007 07:42 pm »

The Falcon 1 launch date is now listed as no earlier than March 9, 2007.

- Ed Kyle