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

[nblackwell]

Flight 5 has slipped under the radar with little news...
I don't even hear the crickets

The news I heard indicates that both parties(especially the SC side) did a lousy job on the basic integration requirements, analyses, design, compatibility and verification.  Connectors were not even compatible.  Concerns now exist about design margins on the spacecraft.  Spacecraft may need to be shipped back to the factory.

On what do you base the assertion that the connectors were not compatible?

[Patchouli]

That's kind of hilarious. And sad. If that's the case, the utter silence from both parties doesn't surprise me anymore.

Concerns about design margins on the spacecraft or on the LV? Wasn't ATSB already involved in a prior F1 flight to acquire integration experience, etc?

My understanding is that the spacecraft was not designed with robust margins.  So any significant updates in the environments, loads, analyses or any evaluation of them could cause problems.

F1's engine was changed to the higher thrust regen Merlin 1C and they likely designed RazakSat for loads seen with the Merlin 1A Falcon without much margin.

One big problem is a lot of other rides they could use likely have worse loads then you see on F1 which may explain why they don't just move to a new LV.

I think the problem area on the satellite likely is the optics.
It is an earth observation sat and if the optics even get knocked out alignment by even the tiniest amount the satellite becomes pretty much blind.

Think about it how many times did NRO have to try back in the early 60s before they got it right?

[Art LeBrun]

Not sure how much optics were an issue in the NRO satellites but the film and film transport were a major concern as well as Agena reliability.

[McDew]

On what do you base the assertion that the connectors were not compatible?

Just that I was told the electrical connections were not compatible.  I guess this could also mean the PIN assignments were messed up instead or

[Nomadd]

F1's engine was changed to the higher thrust regen Merlin 1C and they likely designed RazakSat for loads seen with the Merlin 1A Falcon without much margin.

One big problem is a lot of other rides they could use likely have worse loads then you see on F1 which may explain why they don't just move to a new LV.

I think the problem area on the satellite likely is the optics.
It is an earth observation sat and if the optics even get knocked out alignment by even the tiniest amount the satellite becomes pretty much blind.

Think about it how many times did NRO have to try back in the early 60s before they got it right?

 I'm not sure if the Merlin 1C is a factor. I know they went with it, but I think it was mostly because that's the engine they were producing at that point. It's throttled back to 78,000 pounds because that's all the F1 can handle. The Merlin 1A was rated at 77,000lb, so they're not getting much more thrust by going with the 1C.

[nblackwell]

On what do you base the assertion that the connectors were not compatible?

Just that I was told the electrical connections were not compatible.  I guess this could also mean the PIN assignments were messed up instead or

I do seem to remember something saying that there was a "compatibility" issue, which might be the source of confusion.  Compatibility in this context could easily mean some kind of vibration thing as others have suggested.  Can you give a source that would indicate electrical incompatibility?

[mlorrey]

On what do you base the assertion that the connectors were not compatible?

Just that I was told the electrical connections were not compatible.  I guess this could also mean the PIN assignments were messed up instead or

I do seem to remember something saying that there was a "compatibility" issue, which might be the source of confusion.  Compatibility in this context could easily mean some kind of vibration thing as others have suggested.  Can you give a source that would indicate electrical incompatibility?

Oh man, if its merely a matter of pin assignments, thats fixable in a few hours. If there is an electrical compatibility issue it could mean voltage, frequency, possibly even the payload has excessive power draw on the vehicle bus, or the payload requires signals of a higher voltage than the vehicle sends, or vice versa, and one side of the other is concerned about damage to their side of things.

[Jim]

Oh man, if its merely a matter of pin assignments, thats fixable in a few hours. If there is an electrical compatibility issue it could mean voltage, frequency, possibly even the payload has excessive power draw on the vehicle bus, or the payload requires signals of a higher voltage than the vehicle sends, or vice versa, and one side of the other is concerned about damage to their side of things.

Launch vehicles avionics typically (almost always) don't interface directly with the payload avionics.   Launch vehicles don't provide to power spacecraft.   Spacecraft connectors are for interfacing with spacecraft GSE at the pad.  The spacecraft connectors mate to LV connectors on a harness which lead to umbilical mast and then to the customer's GSE in the pad area.

Any "electrical" interface problems usually are wrong clocking or location of the connectors (mechanical issues)

[Nomadd]

 I've troubleshot many bad interfaces that turned out to be things like people getting sloppy on RS-232/422 standards. The transition points between marks and spaces being off a few percent because of improper impedances is a big one. Any time I integrate serial devices from different manufacturers I use a homemade test box to find the middle of the working signal range to keep everything happy.
 It's one of those things that an old guy who's been taking things apart to see how they work since he was four, and doesn't think Heathkit is a cartoon cat is good at fixing.
 Clocking and pinnout is in the specs, so that would mean a foulup by somebody. 3.2 volt marks because the input imperdence is too low, where the circuit needs at least 3.4v is different people in different countries getting a little sloppy with the standards.
 Then again, it did take me way too long to find b8zs on one end and ami on the other last year.

[butters]

How did we get from "potential impact of predicted vehicle environments on the satellite" to "detected vibration at unsafe level on the launch vehicle" to talking about electrical connector compatibility?

This is my wild speculation: payload dynamic environment at second stage ignition may not have been accurately modeled during the design process, and/or the loads may have increased in flight 4 when they added the five second delay between MECO and separation.

[ugordan]

According to you, what effect would increase the loads at 2nd stage ignition merely due to a delayed ignition, opposed to a much more stressful 1st stage flight?

[butters]

According to you, what effect would increase the loads at 2nd stage ignition merely due to a delayed ignition, opposed to a much more stressful 1st stage flight?

Maybe the change in acceleration.  On flight 2, the first stage engine was still producing residual thrust when the stages separated, so the vehicle never decelerated.  Now the vehicle is allowed to go to neutral thrust before separation, so the ignition may be more violent.  Also the second stage is less massive relative to the payload.

But I'm no expert.  I'm just guessing.

[Nomadd]

According to you, what effect would increase the loads at 2nd stage ignition merely due to a delayed ignition, opposed to a much more stressful 1st stage flight?

Maybe the change in acceleration.  On flight 2, the first stage engine was still producing residual thrust when the stages separated, so the vehicle never decelerated.  Now the vehicle is allowed to go to neutral thrust before separation, so the ignition may be more violent.  Also the second stage is less massive relative to the payload.

But I'm no expert.  I'm just guessing.

It sounds like you might be referring to flight 3, where they had a stage recontact because the new regen engine bled out H2 after separation and caused a burp, pushing the first stage back up. But why would residual thrust on a separated first stage have anything to do with second stage ignition? The second stage is always in freefall before ignition, whether for 1 second or 5.

[dunderwood]

they had a stage recontact because the new regen engine bled out H2 after separation and caused a burp

H2?

[Ben the Space Brit]

IIRC, the troubleshooting on F-1 v5 &RazakSat was expected to last six weeks.  Has there been any indication of a revised launch date?

[ugordan]

IIRC, the troubleshooting on F-1 v5 &RazakSat was expected to last six weeks.

at least six weeks.

[Analyst]

I am not known for being a SpaceX amazing people, but why should they be more specific with their updates, failure reports, delay explanations etc. than the other guys (ULA, Orbital ...)? Shuttle is different because it is NASA.

Analyst

[kraisee]

they had a stage recontact because the new regen engine bled out H2 after separation and caused a burp

H2?

1) An ancient Sanskrit term for kerosene.
2) Or me typing on more many pages than my brain can handle

(My emphasis)

I'm going with Option 2    LOL

Ross.

[Comga]

Does anyone here get Aerospace Defense?
In a news summary this morning there was this from that source on 5/8/2009:

"SpaceX hopes to reschedule a second launch attempt of the Malaysian RazakSAT Earth resources satellite next month. The April delay was due to a potential compatibility issue between the Falcon 1 vehicle and the payload."

Anyone have any information on where this comes from, if it is a real news item or just a rehashing of the old news?

[Antares]

Nothing new in that.