SCRUB: SpaceX Falcon 9 v1.1 - SES-8 - Nov. 28 - SECOND LAUNCH ATTEMPT UPDATES

[Hauerg]

Can someone translate to English?

"The stationary ignition equipment was contaminated." Or somesuch. 

[MP99]

@elonmusk: Abort was caused by oxygen in ground side TEA-TEB. Upper stage on separate internal circuit, so doesn't face same risk.

Good news there is this should either cause clean abort (per Fri), or the engines will start (if a bit slowly) then be OK for the ascent (I presume).

Pad issue helps to explain diff between LC-40 & SLC-4e performance.

Would be interesting to be fly on wall over discussions whether increasing helium pressure would have had desired effect / not interacted badly with poor TEA/B combustion.

I wonder if this is why rocket stayed vertical - to allow continuity checks on pipes / connectors / cabling in the launch config?

Cheers, Martin

[MP99]

Can someone translate to English?

Merlin uses TEA + TEB to help it start up.

These are fed into the vehicle from the pad for launch, but the feed was contaminated so didn't ignite correctly / didn't provide the necessary kick to get the engines started properly.

Interesting question whether this is the same reservoir used for restarts for 1st stage recovery? Edit: IE if marginal for launch might have caused an issue for a restart.

Cheers, Martin

[docmordrid]

Could the "oxygen" have been just air in the lines? Struggling with how a cross contamination could happen from the LOX circuit.

[malu5531]

Could the "oxygen" have been just air in the lines? Struggling with how a cross contamination could happen from the LOX circuit.

According to wikipedia, TEA will react with Oxygen, even LOX, which is why it's useful for starting rocket engines. If there was oxygen contamination in ground side TEA/TEB mixture, does that mean already burning / partially consumed starter fluid (TEA/TEB/O) was used?

[Galactic Penguin SST]

According to Bill Harwood of CBS News the launch window on Monday is 5:41-7:07 pm EST (22:41-00:07 UTC).

[Avron]

I'm not in position to do a full forecast, but looks fairly good. Some unsettled weather Sunday should move out by mid-day Monday. Maybe some leftover clouds and wind.

Rest of the week is beautiful.

Look forward to your update..  So from wx looks like Sunday would not be good Monday is better, lets hope its clear..

[smoliarm]

...

According to wikipedia, TEA will react with Oxygen, even LOX, which is why it's useful for starting rocket engines. If there was oxygen contamination in ground side TEA/TEB mixture, does that mean already burning / partially consumed starter fluid (TEA/TEB/O) was used?

Blue = correct; Red = incorrect.

"oxygen contamination in ground side TEA/TEB mixture" means that "partially depleted starter fluid (TEA/TEB/O)" was supplied to engines.

[smoliarm]

Could the "oxygen" have been just air in the lines?

Unlikely - to spoil significantly just 1 liter of TEA-TEB you need tens of liters of air. I don't think their lines are that long. Also, simple nitrogen purge will do the trick.
A leak which occurred during some (long) time seems more likely. "Leak" here means some flux of air INTO the tank or tubing.

Struggling with how a cross contamination could happen from the LOX circuit.

Me too  any amount of LOX added to TEA in a closed volume = explosion, not contamination.

[MP99]

Three questions if I may.

1) Would M1Dvac likely have TEA/TEB loaded in the hangar, rather than the pad?

2) If so, for flights with a restart, would first stage M1Ds likely have their internal supplies loaded in the hangar?

3) Could, in theory, first stage use its internal hypergol tanks for liftoff (at expense of restarts) if the ground infrastructure is suspect at time of the next attempt?

Thanks, Martin

[ChrisC]

Apologies if this has been posted here already, but I didn't see it.

Here's a nice little writeup by Ben Brockert, CEO of Able Space Co., explaining TEA-TEB ignition systems.  Including a description of the beloved RUD acronym

http://www.wacotrib.com/blogs/joe_science/the-tea-teb-glitch-can-t-light-a-falcon-without/article_1b7c4ae6-5a16-11e3-afbb-0019bb2963f4.html

And don't miss the caveat at the end.

[oiorionsbelt]

Three questions if I may.


3) Could, in theory, first stage use its internal hypergol tanks for liftoff (at expense of restarts) if the ground infrastructure is suspect at time of the next attempt?

Thanks, Martin

I believe only three 1st stage engines are capable of restart. If that's true, then I doubt it would be possible to use the onboard supply to ignite all 9 engines.

[Chris Bergin]

Apologies if this has been posted here already, but I didn't see it.

Here's a nice little writeup by Ben Brockert, CEO of Able Space Co., explaining TEA-TEB ignition systems.  Including a description of the beloved RUD acronym

http://www.wacotrib.com/blogs/joe_science/the-tea-teb-glitch-can-t-light-a-falcon-without/article_1b7c4ae6-5a16-11e3-afbb-0019bb2963f4.html

And don't miss the caveat at the end.

HA! Good info, funny follow up.

Ok, so the thread for the third attempt will be late tonight.

Third time's a charm.

[MP99]

Apologies if this has been posted here already, but I didn't see it.

Here's a nice little writeup by Ben Brockert, CEO of Able Space Co., explaining TEA-TEB ignition systems.  Including a description of the beloved RUD acronym

http://www.wacotrib.com/blogs/joe_science/the-tea-teb-glitch-can-t-light-a-falcon-without/article_1b7c4ae6-5a16-11e3-afbb-0019bb2963f4.html

And don't miss the caveat at the end.

HA! Good info, funny follow up.

Ok, so the thread for the third attempt will be late tonight.

Third time's a charm.

Actually, ISTM that's exactly the caveat you'd hope one of our own on-site experts would post, given the public information he's working with. Something like "there's a small amount of public information, and when I combine that with my own knowledge, this is the interpretation I end up with".

cheers, Martin

[tigerade]

Elon Musk ‏@elonmusk 1m

Engines are cycling cleanly w ground pneumatics. Replaced gas generator on engine 9 (center) as a precautionary measure.

[rdale]

USAF forecasters have a 40% of no-go weather for Monday's attempt - honestly I don't see where that's coming from. I'd put that at about a 4% chance Rest of the week still looks near perfect.

[Chris Bergin]

Hold that thought sir. New thread in about an hour. Please copy and paste latest into it

[Avron]

USAF forecasters have a 40% of no-go weather for Monday's attempt - honestly I don't see where that's coming from. I'd put that at about a 4% chance Rest of the week still looks near perfect.

4% good news.. but will they go tomorrow>

[deltaV]

USAF forecasters have a 40% of no-go weather for Monday's attempt - honestly I don't see where that's coming from. I'd put that at about a 4% chance Rest of the week still looks near perfect.

They're apparently worried about clouds: http://www.patrick.af.mil/shared/media/document/AFD-070716-028.pdf .

[Chris Bergin]

Just so everyone is notified, we're going to the new Attempt 3 Thread now:

http://forum.nasaspaceflight.com/index.php?topic=33398.0

(Remember that is the new UPDATE thread, so updates only. Continue in the discussion threads for other stuff relating to this mission).