Thursday, August 27, 2009

Live At KSC: NASA Plans For Friday Night Launch

NASA aims to launch shuttle Discovery and seven astronauts late Friday, but mission managers still must approve a plan to blast off with a suspect main propulsion system valve and what appears to be a faulty sensor.

Discovery and its crew are tentatively scheduled to lift off from launch pad 39A at Kennedy Space Center at 11:59 p.m. -- the middle of a 10-minute window during which the spaceship can be propelled into the same orbit as the International Space Station.

NASA managers on Thursday decided to pass up a launch opportunity at 12:22 a.m. today so engineers could make certain a critical main propulsion system valve will work as intended before and during flight.

Tests on Wednesday showed the valve and a sensor designed to indicate when it is closed were both working properly. But managers said engineers needed more time to develop a strategy for handling a repeat of valve trouble that triggered a launch scrub earlier this week.

"The better part of valor here is to take a day, let us go polish that (strategy) off, really make sure we understand what's going on," said Mike Moses, chairman of NASA's Mission Management Team.

Engineers on Thursday already were 80 to 90 percent finished with an analysis that will be presented to the Mission Management Team at noon today. A decision on whether to proceed with the near-midnight launch attempt will be made at that time.

The weather forecast calls for a 60 percent chance conditions will be good to go at launch time. But there also is a 40 percent chance that seasonal afternoon thunderstorms could prohibit external tank propellant-loading operations set to begin at 2:34 p.m.

Thunderstorms forced NASA to scrub an initial launch attempt early Tuesday. Then an apparent main propulsion system valve failure resulted in a launch scrub near the end of propellant-loading operations later that day.

NASA engineers think a sensor designed to indicate valve closure might have failed rather than the valve itself. The valve was cycled -- opened and closed -- five times during tests Wednesday evening. Both the valve and the position indicator worked as intended.

Mission managers, however, want to make certain it would be safe to fly if a repeat of the apparent sensor failure cropped up when the valve is exposed to supercold liquid hydrogen -- which is Minus 423 degrees -- during propellant-loading operations. So engineers were sent off to develop a strategy that would enable NASA to ensure the position of the valve even in the event of a sensor failure.

NASA plans to pick up Discovery's stalled launch countdown at 8:34 a.m.. The propellant-loading operation would be complete about 5:30 p.m.

The Discovery astronauts would suit up around 7:39 p.m. and depart crew quarters at the Kennedy Space Center Operations & Checkout Building and arrive at the 195-foot-level of the launch tower at 8:39 p.m.

The Close Out Crew would assist the astronauts as they crawled through the side hatch of the orbiter and strapped into their seats on the flight deck and middeck of the spaceship. The side hatch would be closed for flight at 9:54 p.m.


Anonymous said...

Question for Todd Halvorson or anyone else with actual knowledge:

They say the second most dangerous job in NASA is being a diver involved in retrieving spent shuttle SRBs from the Atlantic. The bigger the ocean swell or "heave," the more dangerous the job.

Tropical Storm "Danny" is sitting off Florida and is supposed to give us a big groundswell for a couple of days, including Friday night - Saturday. Good for surfers; not so great for SRB divers.

Do you know if there is a constraint for wave height in the SRB recovery zone at launch time? And if so, what the maximum allowable wave height is?

Many thanks...

Anonymous said...

Unfortunately, and many probably think of me as way too critical, but this Mike Moses fellow reminds me waaaay too much of Wayne Hale and not nearly enough of Leroy Cain.

Can we get Leroy Cain back?

Next thing you know, Mike Moses will tell me that this valve problem is like if one of the pistons in my pick-up has a tap.

When I want to read Shakespeare, I will read Shakespeare. When I want the shuttle launched, I need someone to sh!+ or get off the pot.

Mike Moses: I you aren't going to launch, send the armed guards home and let me go back to the beach. It's "We the People," not, "We the civilians in charge of NASA" who own the beach. NASA, as part of the Executive Branch of gov't, holds the Canaveral National Seashore "in trust." Well, excuse me, but this track record of yours doesn't inspire too much "trust" from me.

Now, I don't begrudge you all the time in the world to get it right and launch that rocket safely.

But, really, would you just quit closing the beach and refuge weekend after weekend all summer long while you figure out what in God's name you need to do?

Is that too much to ask as a citizen of this country whose ancestors date back to 1647?

Like I said, do what you need to do or get off the pot.


Anonymous said...

By the way, it should be NASA policy, if not law, that the post of shuttle launch director (whatever job Mike Moses has) be filled by an ex-astronaut.

100 years of manipulating a sliderule doesn't begin to equate to riding that beast into space.

There's a place in the world for techno-nerds. Shuttle Launch Director isn't one of them.


Anonymous said...

Is viewing a night launch from Satellite Beach a good view?

Anonymous said...

"Do you know if there is a constraint for wave height in the SRB recovery zone at launch time? And if so, what the maximum allowable wave height is?"

I'm no expert but the SRB's are jettisoned to land in the Indian Ocean, so I'm sure TS Danny isn't a factor. Did make for some pretty good waves, though, if you're willing to work for it.

Todd Halvorson said...


Actually, it's the external tank that drops toward the Indian Ocean. The SRBs are jettisoned and drop into the Atlantic Ocean about 120-150 miles off the coast of Jacksonville. So TS Danny definitely could be a factor for the divers.

And here's a copy-n-paste post from a reader a couple of days back:

Downrange sea states are a consideration, but there is no hard and fast rule:

"A downrange weather advisory shall be issued by the Shuttle Weather Officer to the Mission Management Team for their consideration if the wind in the solid rocket booster recovery area is forecast to exceed 26 knots during retrieval operations. Seas in excess of Sea State 5
(8-13 feet) may also be a factor considered by the Mission Management Team"

Anonymous said...

Where does the external fuel tank drop when the shuttle's trajectory is north along the coast? Does it actually swing back "down" to the Indian Ocean that fast?

Anonymous said...

Actually the tank hasn't landed in the Indian Ocean for probably 20 yrs. Pacific is the target. About 90 minutes after lift off. In many pieces.

Anonymous said...

I think "Microwave" has had his head in the microwave far too long. Judging by some of the comments posted the "me" generation of entitlement is rampant in his ramblings. After all, what is national advancement to one persons tanning?