SpaceX Falcon 9 CRS/SpX-10 Dragon - Feb. 19, 2017 - Discussion

[Herb Schaltegger]

I didn't hear it on today's loop (maybe I missed it), but isn't there a general announcement they make sometime around T-20 minutes or so that no holds will be called after T-30 seconds or something like that? (Meaning that aborts after that are called by the vehicle health management system itself, right?) If so, did someone override that rule and call an abort late or did the vehicle do it?

[AncientU]

As soon as detanking of the launch vehicle starts, a pad crew will be sent to LC-39A.

Why not wait until de-tanking is complete?  Isn't risk to ground crew then minimized?

[ugordan]

There was an announcement on that, but much earlier than T-20 min IIRC. It said that any operator-called hold after T-30 sec has a probability of causing hardware damage.

[fthomassy]

Throwback preceded by a retraction of arms and a 1.5 degree back-off verification of the strongback per commentary.

Optics are a funny thing, it looked like 5° or more.

[Mighty-T]

Second stage TVC issue

TVC?

Thrust Vector Control.

[rockets4life97]

I didn't hear it on today's loop (maybe I missed it), but isn't there a general announcement they make sometime around T-20 minutes or so that no holds will be called after T-30 seconds or something like that? (Meaning that aborts after that are called by the vehicle health management system itself, right?) If so, did someone override that rule and call an abort late or did the vehicle do it?

I'm pretty sure it is the 10 sec mark that is the last manual opportunity to abort (usually by the launch director). We have seen an abort at T-0 which was done by the computer.

It was pretty clear at t-1.30 when the launch director didn't confirm go for launch that they were taking a look at something.

[toruonu]

On NASA TV webcast you could see at around T-2 minutes Elon and about 8 other guys standing around a laptop discussing it actively. It was clear that this was very much still an ongoing issue and I anxiously waited the T-1 minute mark which previously was said to be when they decide the TVC issue if it's go or no go. Once that rolled past and T-20s etc I assumed it was go... oh well...

[leetdan]

There were callouts on the Technical Webcast for AFTS, is that what I think it is?

[ugordan]

As soon as detanking of the launch vehicle starts, a pad crew will be sent to LC-39A.

Why not wait until de-tanking is complete?  Isn't risk to ground crew then minimized?

I just edited my post to support your concern.

This is not the first time you posted an "update" that is not an actual update, but your understanding/assumption on what *should* be happening at a certain point in the count.

Could we stick to actual *updates* in the future, please?

[Wolfram66]

http://jasc-controls.com/jasc-industry-listing/space/space-actuators/thrust-vector-control-actuator-part-101424-5/

Found a reference to the TVC for those who do not know what one looks like or what it does,

[fthomassy]

http://jasc-controls.com/jasc-industry-listing/space/space-actuators/thrust-vector-control-actuator-part-101424-5/

Found a reference to the TVC for those who do not know what one looks like or what it does,

Great, now my advert ribbon is serving up servos

[Eagandale4114]

There were callouts on the Technical Webcast for AFTS, is that what I think it is?

This is the first launch (at least for SpaceX) of an Autonomous FTS system.

[ChrisC]

Raising the strongback to full position. Vehicle safing in progress.

Zach, was this you just relaying what George was saying on NASA TV?  During the countdown he appeared to be reading from an old timeline that called for strongback retract.

[zubenelgenubi]

Did the rainbirds activate?

[old_sellsword]

Raising the strongback to full position. Vehicle safing in progress.

Zach, was this you just relaying what George was saying on NASA TV?  During the countdown he appeared to be reading from an old timeline that called for strongback retract.

The SpaceX webcast did state that the TE let go of the rocket and retracted to about 1 degree before liftoff. Then after the rocket gave the signal for liftoff, it'd do it's full throwback retract.

[Jdeshetler]

Possible similar issue that the thrust vector control actuator had for the Falcon 9’s second stage that aborted CRS-5 two years ago.

https://forum.nasaspaceflight.com/index.php?topic=36490.msg1311428#msg1311428

[wannamoonbase]

This felt like a dress rehearsal since they mentioned the TVC issue. 

Better luck tomorrow. 

[Johnnyhinbos]

Second stage TVC issue

TVC?

Thrust Vector Control.

This part, specifically. It's on all the engines, but the one(s) on the 2nd stage were questionable.
http://jasc-controls.com/jasc-industry-listing/space/space-actuators/thrust-vector-control-actuator-part-101424-5/

And for those, like me, who simply can't get enough, here's a video of a pair of TVCs in action. Posted in 2003 by SpaceX, this is a test of the actuators in a frequency sweep from 1Hz to 14Hz with a gimbal angle of 1.6 degrees in either direction. 

[Coastal Ron]

Not sure whether the "Elon in the loop" and on the fly "99℅" assessment are part of the certification process or not.
We love you Elon, but please no more of these for upcoming crewed flights.

If anything Musk is showing his employees that it's OK to err on the side of caution, which is part of corrective actions they put in place after the CRS-7 flight failure.

As for NASA, they learned the hard way about the consequences of giving in to schedule pressures, or ignoring an abundance of close calls.  So I would hope that NASA is heartened to see how much care SpaceX is putting into safely launching their cargo on this mission, since that helps them to understand what the thinking will be when humans are the cargo.

My $0.02

[punder]

SpaceX having to scrub this morning makes me very happy.

Because I inadvertently slept through this morning's attempt!