Shuttle Launch Delayed

fizzix writes "Weather has delayed the launch of Discovery to tomorrow (Sunday the 2nd), but not everyone thinks it is ready to go. CNN reports both the chief engineer and the chief safety officer gave it a 'no go' for launch. Despite their reservations, barring inclement weather the shuttle is planned to liftoff at 3:26 ET." Update: 07/02 05:00 GMT by Z : I said launch not lauch. Fixed headline.

Comments

SpaceFlightNow (as usual) has great coverage

[xmas2003]

STS-121 Mission Status Center - 'nuff said.

Slight confusion over the submital

[beebware]

The details in the Slashdot posting are slightly incorrect. Todays/yesterdays launch (the scheduled on on the 1st of July) was postponed at T-9minutes after a 40 minute scheduled hold (if it's scheduled, why didn't they add it into the count down?) and approximately 3 minutes of 5 into an "extended hold" (after they "polled" all the various sections of the launch team). Then the decision was made the "scrub" (abort) the launch due the weather being too unpredictable and there being storm clouds (anvil clouds) within 20 miles of the emergency landing strip (although they have got backup landing strips in France and Spain). They will retry the launch tomorrow, and can abort for any reason up to 31 seconds before main ignition.

At the moment, they are still "go" for the launch tomorrow.

BTW: You learn a lot from watching the live stream on nasa.gov!

Re:Slight confusion over the submital

[DarthBart]

can abort for any reason up to 31 seconds before main ignition.

The folks in the firing room can abort up to 31 seconds before T-0, but the onboard computers can abort anytime before the SRBs light. Once those puppies light, you're going whether you like it or not.

Re:Slight confusion over the submital

[endernet]

The 45 min hold at T-9:00 is standard. It's used for making up time if they take too long on some pre-flight procedures. I think there is a 10min scheduled hold in there at about T-20:00 as well. Why is it not included in the countdown? Because they can chose to use all the 45 min, or only some of it.

Re:Slight confusion over the submital

[Anonymous Coward]

storm clouds (anvil clouds) within 20 miles of the emergency landing strip (although they have got backup landing strips in France and Spain)

Just a small correction there; the strips in France and Spain aren't backup strips, the two locations serve different purposes. If there is a failure early in the launch sequence then they can in theory just ditch the attachments, turn around, and land at the emergency strip near the launch site. ("In theory" because this maneuver is so insanely difficult that it's been said to require about seven different miracles to be successful.) Past a certain point the shuttle can no longer make it back to Florida, so then the abort procedure changes to continue approximately on course and land on the far side of the Atlantic. This part is where the sites in France and Spain come into play. There are few, if any, scenarios where either side could be used, so you end up with a weird situation where bad weather in a place four thousand miles away can scrub the launch because you need to be able to abort there if something goes badly wrong.

Today was the opposite. The transatlantic sites were clear but the strip in Florida itself was too cloudy, so they couldn't go.

This is yet another advantage of simpler capsule systems. The abort modes for those are all extremely simple and reliable compared to the Shuttle's. You fire the escape tower, get away from the rockets, ride down and open the parachutes when you get to the right altitude. As long as the weather isn't so horrible that it sinks the capsule in the ocean, everything should be pretty much fine.

Apollo 12 got hit by lightning during launch and still landed on the Moon, but the Shuttle can't launch if there are storm clouds within 20 miles. The wonders of modern technology.

Re:Slight confusion over the submital

[LoveMuscle]

Just to be clear: T-0 is defined as SRB ignition.

Re:From the article ...

[glitchvern]

There's no good reason for NASA to launch the shuttle over the July Fourth holiday weekend

Sure there is, the launch window is 10 minutes a day from June 30 to July 19. The two previous sets of launch windows were March 4 to 19 and May 3 to 22. Nasa missed both of those so now they are trying this one. I am not sure why a launch on June 30 was not tried, but that still would have been part of the 4th of July weekend. Generally speaking you want to try launching early in the set of launch windows so if you have a delay you might be able to launch in the next day's window. More info on launch windows here, here, and here.

Re:Hold on

[RedWizzard]

So if the engineer says no, and the safety officer says no then who is saying yes? Whose opinion could be more important than these two people?

The chief engineer Chris Scolese and the associate administrator of Safety and Mission Assurance Bryan O'Conner are there to advise. That is what they do. The decision is made by the NASA Administrator Mike Griffin. His rationale for proceeding include that there is no undue risk posed to the crew (the crew can wait for rescue at the ISS), no short or medium term fix has been identified, and continued delays may cause greater risk down the line as NASA scrambles to complete the 16 missions they need to before the fleet is grounded in 2010. There is also the feeling that since the external tank redesign they've just done is so significant (biggest change to the aerodynamics since the shuttle started flying), it would be wise to have a flight with that change alone rather than waiting for further redesigns.

Re:End the damn program already

[evanbd]

Commercial efforts so far? Almost, but not quite, recreating a 57 year old X-15 flight, courtesy of a couple of very rich angels. Commercial efforts will get there, but not anytime soon. Gotta satisfy those shareholders.

Don't sell SpaceX quite so short -- they've attempted one *orbital* launch, and will be trying again in a couple months. There's good reason to believe it will work -- the failure was a procedural one, not a design one, and they've added multiple checks to prevent it and similar problems. The current rocket (Falcon 1) is a small TSTO semi-expendable launcher; they have a larger Falcon 9 and some variants also already in production, and a much larger rocket (codename: BFR) and manned (!) capsule in development. I'd lay better than even money they repeat the Sputnik flight (with a useful payload) this year, and even money they do a manned launch in 5.

Commercial will get there, it's just a matter of putting enough investment in to get to the point that there's a market, and SpaceX has already sold 10 launches -- strongly suggesting that there is in fact a market for better, cheaper, more reliable vehicles.