Updates STS-134 Updates

[Star Voyager]

Diller now reports that the scrub could be longer than 48 hours. LD Mike Leinbach will discuss this issue in just a few minutes.

 

[garyw]

And they scrub it just like that? They've got 2h and a half, for Probe's sake. Couldn't they wait, and then scrub it after that time if not resolved?

No. to give it some context

The engineering team saw a problem. Two of the three APU heaters didn't work. They didn't understand the problem and weren't happy. They wanted to do some electrical tests but can't do that with a fueled shuttle as it involves going into the aft section.

Even if the problem fixed itself it's something they can't ignore. It IS against launch commit criteria rules.

therefore the only option they had was to call for a scrub so they can investigate the issue.

Worst case scenario if they ignored it - a launch, two APU's failing and an emergency deorbit. Not worth it at all.

 

[DaveS]

And they scrub it just like that? They've got 2h and a half, for Probe's sake. Couldn't they wait, and then scrub it after that time if not resolved?

They can't resolve it from the Firing Room. They're suspecting a short so they need to enter the aft engine compartment where the APUs live and that can only be done with the RSS in place.

 

[diogom]

Lets hope it's nothing serious, or we'll have another STS-133.

 

[garyw]

It IS serious because it was scrubbed. Right now, all anyone can do is wait for the engineering teams to go out and asses. They won't start looking at the problem until the shuttle is safed which due to the time it takes to drain the tank will be tomorrow at the earliest.

 

[diogom]

Thanks guys for explaining, didn't think it was thathard to troubleshoot.
EDIT: I meant "continuous scrubs and delayed for a month" serious.

 

[garyw]

It's not hard to troubleshoot once they get into the aft and have a good look. Getting into the aft of a fueled shuttle is very dangerous hence the scrub.

It's not yet clear how long it will take to resolve the problem, but launch is off until at least Sunday, at 2:59:38 p.m. EDT (GMT-4). The forecast for calls for an 80 percent chance of good weather, but it's not yet clear whether the problem can be resolved in time to support a launch attempt Sunday.

The problem cropped up as Kelly and his crewmates were suiting up for launch. Two heaters on one of the shuttle's three hydraulic power units failed, allowing the temperature in propellant lines to drop below acceptable limits.

The auxilliary power units, or APUs, provide the hydraulic power to move the shuttle's engine nozzels, wing flaps and landing gear brakes. Engineers suspect a blown fuse may be to blame but it's not yet clear what caused that or what might be needed to fix it.

"Our NASA launch director Mike Leinbach has made the decision ... that we're not able to resolve this situation with the APU heaters in time to make a launch attempt today," said NASA launch commentator George Diller. "There's not a way to do the kind of troubleshooting we need to do and sill be able to stay in a count configuration. So we will be scrubbing for today.

"Right now, it will be at least a 48-hour scrub turnaround while we try to get a better handle on understanding what the problem is. As we've been able to piece it together, there will be some entry into the aft (engine compartment) to do that troubleshooting."

 

[diogom]

Here I was, ready for it, only a pack of popcorns left. :lol:
Due to something about the payloads, couldn't get it fully, maybe a 72h.

 

[Star Voyager]

CONFIRMED. Minimum 72 hours scrub called by Leinbach.

 

[Bonanza123d]

Yep This will be a good time to get to go up and see if for yourselves. Although there must be a meting spot for all the orbinauts out there.

 

[Kyle]

Launch windows:

Mon May 2nd - 02:33:56 PM
Tue May 3rd - 02:11:25 PM
Wed May 4th - 01:45:43 PM
Thu May 5th - 01:23:11 PM
Fri May 6th - 12:57:29 PM

 

[diogom]

Conference scheduled for 4 p.m. EDT.

 

[garyw]

CBS News Update

Well worth subscribing to these updates:

CBS NEWS Coverage of Breaking Space News

-- Posted at 12:46 PM EDT, 04/29/11: Hydraulic system glitch grounds shuttle Endeavour
-- Updated at 01:35 PM, 04/29/11: Launch delayed at least 72 hours; quotes and details

By WILLIAM HARWOOD
CBS News

KENNEDY SPACE CENTER, FL--Problems with the shuttle Endeavour's hydraulic power system forced NASA managers to scrub Friday's planned launch on a space station assembly mission, disappointing thousands of spectators and spoiling a planned visit by President Obama and his family.

It also was a disappointment to commander Mark Kelly's wife, Gabrielle Giffords, who flew to Florida to watch the launch as she recovers from a January assassination attempt.

It's not yet clear how long it will take to resolve the problem, but launch is off until at least Monday, at 2:33:56 p.m. EDT (GMT-4), and possibly longer.

The problem cropped up as Kelly and his crewmates -- pilot Gregory H. Johnson, Michael Fincke, Gregory Chamitoff, Andrew Feustel and European Space Agency astronaut Roberto Vittori -- were suiting up for launch.

Two heaters on one of the shuttle's three hydraulic power units failed, raising the possibility that temperature in propellant lines to drop below acceptable limits. The "astrovan" carrying the astronauts to launch pad 39A was stopped at the launch control center while engineers continued discussing the issue.

A few minutes later, Launch Director Mike Leinbach called off the countdown, ordering a scrub. The astrovan turned around and headed back to crew quarters.

President Obama and his family planned to visit the Kennedy Space Center as planned, but no details were immediately available.

The auxiliary power units, or APUs, provide the hydraulic power to move the shuttle's engine nozzles, wing flaps and landing gear brakes. Engineers suspect a blown fuse may be to blame but it's not yet clear what caused that or what might be needed to fix it.

"The exact problem was a thermostat on one of the fuel lines for that auxiliary power unit and we need to keep those lines warm to prevent them from freezing on orbit," Leinbach said. "So we have two thermostats, two heaters for each fuel line for each APU."

"And on auxiliary power unit No. 1, one of those two heater units failed and the trouble shooting we did on it proved it was a hard failure, we were not able to get it to come to life no matter what we did.

"We tried to let the line cool down just by normal means to see if the thermostat on that heater would kick in. That did not happen. We tried to command the heater from the cockpit of the orbiter, that did not happen either. So we know we had a hard failure in that heater string for that one auxiliary power unit. There was another heater upstream of that that's also exhibing some funny behavior."

As a result, engineers believe a failure occurred in or near a load control assembly, or LCA, in the shuttle's aft engine compartment. The data indicate "we probably have a short in that box or in one of the electrical lines to that box or from that box," Leinbach said. "We're not quite sure yet, we won't know until we get into the aft of the orbiter and do some detailed troubleshooting."

"But the issue is, we didn't want to commit to flight with only one of two heaters on those auxiliary power unit fuel lines??because of the chance if you lost that one good one on orbit, you run the very high risk of freezing the fuel in that line and therefore the auxiliary power unit would not function and therefore you wouldn't have full hydraulic power, which is a case you never want to get into for re-entry."

After draining Endeavour's external tank, engineers will open the aft engine compartment to gain access to the suspect hardware.

"Probably tomorrow afternoon we'll get into the aft, start putting in our platform set to get to this load control assembly, which is down inside the aft quite a ways and so it's going to take us a bit of time to get in and do that," Leinbach said. "And then once we're in the avionics bay we'll be able to do our troubleshooting."

Endeavour's launch window extends through May 4. If the shuttle is not off the ground by then, the team will stand down for three days to reload liquid oxygen and hydrogen fuel cell reactants and to give the Air Force time to launch an Atlas 5 rocket carrying a military missile early warning satellite. The shuttle launch window would re-open around May 8 and extend through May 29.

 

[N_Molson]

Glad they noticed this. An APU failure would have been very nasty ! :hide:

 

[diogom]

Am I mistaken, or has Obama just landed in KSC? Doesn't make sense, since he would have been warned it was scrubbed, and it's not a B-747.

---------- Post added at 06:18 PM ---------- Previous post was at 06:16 PM ----------

Yap, it's Obama.

 

[IronRain]

Scrub announcement

Scrub explanation

 

[jgrillo2002]

goddamnit. this shuttles are falling apart and these scrubs are getting more and more frequent. Id say cancel the whole program right now before more lives are lost

 

[DaveS]

goddamnit. this shuttles are falling apart and these scrubs are getting more and more frequent. Id say cancel the whole program right now before more lives are lost

Calm down. The orbiters are not "falling apart". They're just fine. Sometimes parts fail due to normal wear or processing induced damage. This is exactly the reason why they do have some things called "Launch Commit Criteria". If any LCC is violated and not resolved a launch cannot proceed.

 

[Star Voyager]

Hence the phrase "scrub turnaround".

 

[Orbinaut Pete]

goddamnit. this shuttles are falling apart and these scrubs are getting more and more frequent. Id say cancel the whole program right now before more lives are lost

Oh yes. Brilliant idea. And how do you suggest we get all that vital payload up to the ISS?