SpaceX: Falcon 9 Hotfire Attempt 2 Updates

[mlorrey]

I think its a positive thing to see that they are operating tightly right now. Looking forward to hearing more about this spin start issue. Curious as to why they need to have such tight tolerances wrt the spin starts and why it causes so many aborts in Texas.

[kkattula]

That is definitely something that should not become SOP. Aborting after ignition and safing a vehicle should be a safety net, not an accepted thing. Like a LAS for crewed launches.

Just my 2c.

Unless maybe you have designed a vehicle that can startup & shutdown, tank & de-tank, repeatedly, without a great deal of effort or adverse effects or undue expense.

Avoids 'Go Fever'.

Aircraft abort take-offs, flights & landings all the time.  It is SOP and contributes to safety.

[A_M_Swallow]

That is definitely something that should not become SOP. Aborting after ignition and safing a vehicle should be a safety net, not an accepted thing. Like a LAS for crewed launches.

Just my 2c.

Unless maybe you have designed a vehicle that can startup & shutdown, tank & de-tank, repeatedly, without a great deal of effort or adverse effects or undue expense.

Avoids 'Go Fever'.

Aircraft abort take-offs, flights & landings all the time.  It is SOP and contributes to safety.

Having an abort facility is useful.  However frequent aborts means that something is not being controlled properly or operates outside the limits the design is built to handle.  I hope this is not a symptom of a deeper problem.

[kevin-rf]

I would be worried about the second stage. If the rpm's are not in the proper range on startup will it not fire in flight? With the first stage you never leave the pad and can recycle. At staging you end up in the hydrosphere.

[ugordan]

I would be worried about the second stage. If the rpm's are not in the proper range on startup will it not fire in flight?

There is a difference between "would not fire" and "ignition was aborted". I take it there are no tight abort limits for MVac simply because the launch commit was already given and there's nothing to lose. Who's to say the 9 Merlins wouldn't have fired up anyway if the sequence wasn't cut off prematurely?

[kevin-rf]

I ment abort the ignition... That we do not know.

[kkattula]

I would be worried about the second stage. If the rpm's are not in the proper range on startup will it not fire in flight?

There is a difference between "would not fire" and "ignition was aborted". I take it there are no tight abort limits for MVac simply because the launch commit was already given and there's nothing to lose. Who's to say the 9 Merlins wouldn't have fired up anyway if the sequence wasn't cut off prematurely?

Exactly.  If the first stage isn't quite perfect, you can abort and try again in an hour, or tomorrow, or next week.

If the second stage isn't quite perfect, you might as well keep going. There's no reset option.

[William Barton]

I would be worried about the second stage. If the rpm's are not in the proper range on startup will it not fire in flight?

There is a difference between "would not fire" and "ignition was aborted". I take it there are no tight abort limits for MVac simply because the launch commit was already given and there's nothing to lose. Who's to say the 9 Merlins wouldn't have fired up anyway if the sequence wasn't cut off prematurely?

Exactly.  If the first stage isn't quite perfect, you can abort and try again in an hour, or tomorrow, or next week.

If the second stage isn't quite perfect, you might as well keep going. There's no reset option.

Which points to an interesting (slightly OT) speculation: If they ever succeed in getting second stage recovery, would they then want to implement in-flight abort for it? I realize throwing the payload in the sea would be a big complication, but if the stage fails, it's going in the sea anyway.

[ugordan]

Which points to an interesting (slightly OT) speculation: If they ever succeed in getting second stage recovery, would they then want to implement in-flight abort for it?

If they want to eventually man the F9, they'd need abort checks on the 2nd stage anyway. That would include startup checks. The point of the first couple of flights is to characterize the engine startup and just get it to light, then once man-rating is attempted some limits on anomalous startup/operation can be set, based on what would be dangerous for the engine.

[go_spacex]

Which points to an interesting (slightly OT) speculation: If they ever succeed in getting second stage recovery, would they then want to implement in-flight abort for it?

If they want to eventually man the F9, they'd need abort checks on the 2nd stage anyway. That would include startup checks. The point of the first couple of flights is to characterize the engine startup and just get it to light, then once man-rating is attempted some limits on anomalous startup/operation can be set, based on what would be dangerous for the engine.

Clarification:
With humans on board you would have active startup and mainstage operation aborts that would trigger the crew escape system. These abort levels would not be established using flight data, they would be established during ground qualification testing (which would be performed to man rating standards).

With any other payload, you would never run S2 in-flight aborts. Once you’re in the air there’s nothing you can do.

[Robotbeat]

Which points to an interesting (slightly OT) speculation: If they ever succeed in getting second stage recovery, would they then want to implement in-flight abort for it?

If they want to eventually man the F9, they'd need abort checks on the 2nd stage anyway. That would include startup checks. The point of the first couple of flights is to characterize the engine startup and just get it to light, then once man-rating is attempted some limits on anomalous startup/operation can be set, based on what would be dangerous for the engine.

Clarification:
With humans on board you would have active startup and mainstage operation aborts that would trigger the crew escape system. These abort levels would not be established using flight data, they would be established during ground qualification testing (which would be performed to man rating standards).

With any other payload, you would never run S2 in-flight aborts. Once you’re in the air there’s nothing you can do.

Mightn't SpaceX allow DragonLab aborts? If you have millions of dollars in equipment (plus the cost of the capsule), it might make sense to recover it, especially since spacecraft tend to be much more expensive than their launch vehicles. It might help lower insurance rates (eventually) and make relaunching in case of a failed launch vehicle far quicker and cheaper. Usually, if you have a launch vehicle failure, doesn't it take quite a while to relaunch a certain payload, since you have to build a whole new spacecraft? Insurance money can't keep your company in business if you needed to launch a spacecraft. A few years of lost profits isn't going to be recovered by just insurance money.

[ugordan]

http://flametrench.flatoday.net/2010/03/spacex-falcon-9-engine-test-firing.html

SpaceX might try again today to test-fire the nine Merlin 1C engines on the first stage of its Falcon 9 rocket at Cape Canaveral Air Force Station. Officials, however, are putting an emphasis on the word "might".

But as you can see (from the still images above), the weather almost certainly will be a factor. It's been raining at the Cape and conditions at Launch Complex 40 are less than desirable.

Weather forecast is awful for today and tomorrow.

[stockman]

http://flametrench.flatoday.net/2010/03/spacex-falcon-9-engine-test-firing.html

SpaceX might try again today to test-fire the nine Merlin 1C engines on the first stage of its Falcon 9 rocket at Cape Canaveral Air Force Station. Officials, however, are putting an emphasis on the word "might".

But as you can see (from the still images above), the weather almost certainly will be a factor. It's been raining at the Cape and conditions at Launch Complex 40 are less than desirable.

Weather forecast is awful for today and tomorrow.

Yea... foggy down there today...

[ugordan]

I don't think that's fog. Rain curtain comes to mind...

[Avron]

Ok, question, what is the minimum acceptable weather for a Static test fire..

[stockman]

I don't think that's fog. Rain curtain comes to mind...

you could be right... Yuck!!!

[zerm]

Visit...

http://www.klydemorris.com/strips.cfm

[stockman]

Visit...

http://www.klydemorris.com/strips.cfm

LOL... thats funny.. I wonder what 3rd party web site they could be referring to???   hmmmmm 

[kevin-rf]

Which points to an interesting (slightly OT) speculation: If they ever succeed in getting second stage recovery, would they then want to implement in-flight abort for it? I realize throwing the payload in the sea would be a big complication, but if the stage fails, it's going in the sea anyway.

Other than you are talking the difference between recovering a fully fueled upper stage and an empty upper stage... You'll need bigger a parachute

[stockman]

Now reported at SNF

"SpaceX could attempt another static fire this afternoon, but that is a "big maybe," company officials say. Scattered showers and thunderstorms are passing across Central Florida today, but the impact of weather on the Falcon 9 rocket's engine test is unclear.
The strongback will be partially retracted away from the rocket before fueling occurs. "

http://www.spaceflightnow.com/falcon9/001/status.html