LIVE: SpaceX Falcon 1 Launch 5 (RazakSat) - July 13/14

[pm1823]

Wonder, what can "vibrate at unsafe level" for satellite in LV - before the launch? Do they shake Falcon and listen "rattle-bladder" sounds?  

[tobi453]

Maybe they did a static fire test?

[pm1823]

Maybe, but they always report about "static fire test" in Updates. It's kinda "milestone".

[edkyle99]

Wonder, what can "vibrate at unsafe level" for satellite in LV - before the launch? Do they shake Falcon and listen "rattle-bladder" sounds?  

A couple of possibilities related to "vibration". 

One, they may have monitored vibration with accelerometers during shipping.  If some maximum level, probably from a shock, was recorded, they may have to perform some type of extensive inspection or re-qualification protocol on whatever part (stage, engine, fairing, etc.) was involved.

Two, something may have cropped up during a propellant loading test.  I once heard a Centaur stage *scream* when something "vibrated" during a pressurization test.  Techs had to wear ear protection during subsequent troubleshooting tests.   

 - Ed Kyle

[[email protected]]

There is one other possible explanation, and it isn't technical, but political.

Suppose the SATELLITE has a problem, and it would be embarassing for the Malaysian gov't (or the cronies therein) to acknowledge that they missed an important design / assembly flaw.

What better way for a politician to CYA than to declare that the launcher isn't ready?

SpaceX needs the contract, and can notify others through back-channels what the "real" deal is.

The politicians need to protect their phony-baloney jobs. 

Launch occurs, hopefully a complete success (at least for SpaceX), and everybody is happy -- and the Malaysian people are none the wiser.

[William Barton]

Are rocket stage tanks purged with dry nitrogen (or some equivalent) prior to fueling? I can't imagine you'd want any condensation, especially in the LOX tank. Or leak checked with freon (or modern equivalent), for that matter? Forgive me for being such an old timer. I switched from big, dangerous machinery to safe (warm, indoor) computers 25 years ago. Anyway, that'd be a couple of ways you might start an unexpected vibration in a fuel line or something.

[Jim]

There is one other possible explanation, and it isn't technical, but political.

Suppose the SATELLITE has a problem, and it would be embarassing for the Malaysian gov't (or the cronies therein) to acknowledge that they missed an important design / assembly flaw.

What better way for a politician to CYA than to declare that the launcher isn't ready?

SpaceX needs the contract, and can notify others through back-channels what the "real" deal is.

the back channel idea isn't valid.  Spacex would need to make a public statement

[Nomadd]

 Maybe a chance they didn't have F1 specs in hand when they designed the satellite, and were late in realizing the normal max vibration of the launcher was higher than the sat was rated for? It seems unlikely Spacex wouldn't pick that up when they accepted the contract, but it wouldn't be the first dumb mistake in the business.
 
 I wonder if they do like I do when evaluating dish mounts and tie wrap an Iphone with the vibration app to the structure. The thing is remarkably accurate measuring 3 axis frequency and amplitude. Even e-mails you the results so you don't have to climb up to see them.

[G-pit]

Since the NET date is tomorrow, could someone comment on whether or not the rumors of a delay have been reliably confirmed? Thanks.

[carlosn]

Re: Vibration Issue
It is not uncommon for  some eager engineer to do one last analysis and find out that something is wrong days before a launch.  In this case I would speculate that someone figured out the vibration levels at some component on the s/c were probably unsafe.

Re: Satellite Issue
Again, not uncommon for satellite provider and launch provider to play launch chicken in trying to place the blame for the delay on the other party - even though in all likelihood both parties might have had delays of their own.

[Jim]

Maybe a chance they didn't have F1 specs in hand when they designed the satellite,

no chance, they have been available for years

[Patchouli]

A new rocket and a new sat from someone new to manufacturing satellites and a remote sensing satellite at that.

Making optics able to survive launch vibrations is not a trivial task so a delay is to be expected.

F1 is one of the few small LVs that can place a payload in NEqO due to it's launch site in Omelek.
Pegasus is the only other small LV I know of that can reach near equilateral orbit but the vibration environment on it is probably worse then F1.

[braddock]

SpaceX has apparently released a PR (not yet on web site nor sent to the usual mailing lists).

http://www.spaceflightnow.com/news/n0904/19falcon1/
http://www.space-travel.com/reports/SpaceX_Delays_Falcon_1_Razaksat_Launch_999.html

"While both the Falcon 1 vehicle and satellite passed all preliminary checkouts and are cleared for launch, a concern has been identified regarding the potential impact of predicted vehicle environments on the satellite."

[William Graham]

Maybe a chance they didn't have F1 specs in hand when they designed the satellite,

no chance, they have been available for years

IIRC, this was originally intended for launch on the Merlin-1A powered F1. The 1C version could have a slightly different profile.

[ugordan]

<speculation>

The Merlin-engine-induced difference is an interesting possibility. The higher thrust on Merlin 1c would imply a more stressful max-Q acoustic environment than the original Merlin 1a would produce. If this is the case I wonder where the requirement change was lost and who is to blame. So far we have two news reports pointing the finger at SpaceX and coming from the customer.

If it's a max-Q thing I can imagine two possible fixes:
1) downrate the Merlin 1c
2) beef up acoustic blankets in the fairing

Option #2 seems more reasonable to me, easier to implement and less dangerous from a systems engineering standpoint than further downrating the Merlin from nominal thrust levels. Certainly looks more favorable than lowering the performance of the booster.

One also wonders if the 6+ week figure is the actual amount of time required or if it's primarily driven by range availability.

</speculation>

[Jim]

The higher thrust on Merlin 1c would imply a more stressful max-Q acoustic environment than the original Merlin 1a would produce

That shouldn't be that big of difference and it just would be max-q.  Max-q environment is more vibration than acoustical.

[kevin-rf]

F1 is one of the few small LVs that can place a payload in NEqO due to it's launch site in Omelek.
Pegasus is the only other small LV I know of that can reach near equilateral orbit but the vibration environment on it is probably worse then F1.

Now retired Scout from the San Marco platform east of Kenya.

Is Vega going to fly from San Marco?

[Skyrocket]

Is Vega going to fly from San Marco?

No

[kch]

Is Vega going to fly from San Marco?

No

ELA-1 at Kourou.

[Spacenuts]

Can anyone with experience in this specific problem answer a quick question?  Couldn't it be as simple as the Razaksat being built too close to the margin for vibration or acoustics while at the same time the Falcon 1 in its current configuration also comes close to being maxed out?  Then during final checks someone spoke up and said "Hey! Shouldn't we have more margin for error here?"  Given how close this is to launch after such a long time a few weeks seems a small price to pay to eliminate a tight squeeze.  Since the launcher can be modified with greater ease it gets the attention.  SpaceX wants a flawless event so it would be to everyones benefit.  The press releases all seem to follow that pattern.