SpaceX Falcon 9 v1.1 - SES-8 - DISCUSSION THREAD

[douglas100]

Yes, neither Atlas nor Delta do static firings on the pad before launch. And I don't think the second Antares did either. Static firings seem to be a SpaceX "specialty."

[Avron]

Hopefully , in the near future the hold down test, will be enough for F9..R

[kevin-rf]

I thought the original Delta IV did an aborted ignition as part of the prep for first flight and a static firing was not done on the Atlas V engine because it would reduce the life of the RD-180. I remember some sort of dust up about that when the first EELV's flew.

Maybe Jim remembers, but it is worth noting that Boeing quickly dropped the test after the first flight. It would make sense for SpaceX to drop the static fire once they build up enough history with the engine.

Edit: Also there was some snide remarks in the orbital threads about Antares hot fire. The Antares hot fire was needed because a full up static test stand was not built and the pad was used for those tests. It was a cost cutting measure that raised a few eyebrows. SpaceX has a test stand in Texas that they use quite often, so once they get the history, there is no reason for it at Vandenberg or the Cape.   

[Lars_J]

Reusability changes the way you test things, I imagine. You no longer have brand new components that have passed individual test back at the production line.

So IF re-usability becomes a reality, I think SpaceX could continue to do hot-fire tests. It might be the best way to verify engine health before each liftoff, if you don't want to disassemble the whole thing every time.

[guckyfan]

Reusability changes the way you test things, I imagine. You no longer have brand new components that have passed individual test back at the production line.

So IF re-usability becomes a reality, I think SpaceX could continue to do hot-fire tests. It might be the best way to verify engine health before each liftoff, if you don't want to disassemble the whole thing every time.

I see them do the test fire for quite a while. But IMO they will not do the qualification firing in McGregor forever. That's where a lot of money goes.

[Lars_J]

Reusability changes the way you test things, I imagine. You no longer have brand new components that have passed individual test back at the production line.

So IF re-usability becomes a reality, I think SpaceX could continue to do hot-fire tests. It might be the best way to verify engine health before each liftoff, if you don't want to disassemble the whole thing every time.

I see them do the test fire for quite a while. But IMO they will not do the qualification firing in McGregor forever. That's where a lot of money goes.

Of course... But the long term plan is probably not to bring reused stages to McGregor between every flight.

[Galactic Penguin SST]

The answer to whether a WDR/static fire is planned and the time of WDR and static fire is on the SES-8 thread at L2.

[Chris Bergin]

The answer to whether a WDR/static fire is planned and the time of WDR and static fire is on the SES-8 thread at L2.

Yeah, we have to run the updates in L2. But I will be writing an article for the upcoming Static Fire dual test.

Launch date is still the 22nd at this time. If a launch date changes I tend to share as soon as is viable for those planning to attend, etc.

[Jim]

I don't think so. Why would they eliminate static fire? I know they don't do static fire on vehicles that use solids because you can't turn a solid off. But confirmation of proper firing capability prior to launch day seems highly desirable to me.

Unneeded.  The stages are static fired before shipped to the launch site.  Same goes for WDR. 

Having strapon solids does not preclude a static fired.  See shuttle

Delta IV still does WDR because the stages has yet to see any cryogens and it is a fairly new design.   Atlas has legacy behind it and feels that it doesn't need a WDR.  Elimination of it is only a schedule risk.  If there is a issue found at the first launch attempt, they fix it and try again. 

[Jim]

I see them do the test fire for quite a while. But IMO they will not do the qualification firing in McGregor forever. That's where a lot of money goes.

Static fire will likely end before qual firings.

[Garrett]

From the updates thread:

CRS-3 article on L2 info on the EMU up and down tasks for Dragon and launch date considerations - including SES-8:

http://www.nasaspaceflight.com/2013/11/spacex-crs-3-dragon-spacesuit-relay/

So no separate WDR on this mission.  Pretty bold to go straight to hot fire if that includes the payload on top (I believe that's what's been done on all prior 1.0 and 1.1).

CRS-1 static fire did not have a Dragon on top. I would not expect SES-8 to be on the stack during the upcoming static fire. Maybe somebody can confirm?

[smoliarm]

From the updates thread:

...

So no separate WDR on this mission.  Pretty bold to go straight to hot fire if that includes the payload on top (I believe that's what's been done on all prior 1.0 and 1.1).

CRS-1 static fire did not have a Dragon on top. I would not expect SES-8 to be on the stack during the upcoming static fire. Maybe somebody can confirm?

Yes, I remember (at least for some F9 - Dragon flights) static fires w/out payload.
However, for the last mission they did static fire with CASSIOPE attached.

http://i.space.com/images/i/000/033/201/original/spacex-falcon-9-upgrade-test-fire.jpg

http://www.space.com/22992-spacex-private-falcon9-rocket-test-launch.html

[IRobot]

How big is the risk of the payload being damaged or destroyed during a static test nowadays?

Has there been any record of a destructive static test, at least in recent years? Or is this more of a insurance company demand?

[Roy_H]

How big is the risk of the payload being damaged or destroyed during a static test nowadays?

How big does a risk have to be, especially if there is no point in taking any risk at all? It is trivial to static fire without the valuable payload, then back to assembly hangar and attach load.

[IRobot]

How big is the risk of the payload being damaged or destroyed during a static test nowadays?

How big does a risk have to be, especially if there is no point in taking any risk at all? It is trivial to static fire without the valuable payload, then back to assembly hangar and attach load.

There are some obvious advantages of doing the static fire with the payload on: cost and time. The question is if it pays off the risk.

[dcporter]

Current plan is no payload for static fire. Not sure if it's insurance, customer request, or what...

Thanks padrat! Is that unusual?

[Roy_H]

There are some obvious advantages of doing the static fire with the payload on: cost and time. The question is if it pays off the risk.

I hate to be picky, but what cost and time? The time to attach the payload should be the same if it was done before or after the static fire test.

[Jim]

Current plan is no payload for static fire. Not sure if it's insurance, customer request, or what...

Thanks padrat! Is that unusual?

that is SOP.

[HIP2BSQRE]

has anyone seen or read either study?  Where can I read them?

[Lar]

There are some obvious advantages of doing the static fire with the payload on: cost and time. The question is if it pays off the risk.

I hate to be picky, but what cost and time? The time to attach the payload should be the same if it was done before or after the static fire test.

If you have a static fire without a payload you have to roll back to attach it. It's conceivable that you could see a flow that looks like

- integrate stages
- integrate payload
- roll out to pad
- WDR
- Static test fire (possibly combined with WDR)
- launch

in which there is only one rollout.

It may not be practical yet, but it's conceivable. And if you are looking to drive out cost from your process flow, one less rollback/rollout seems like it might save a bit.