Space Shuttle Discovery to Launch July 26

thhamm writes "According to Space.com: 'NASA will restart the countdown for the space shuttle Discovery Saturday, with plans to launch the orbiter spaceward on July 26 after more than a week of work to pin down a fuel sensor glitch, mission managers said late Wednesday'. In the meantime, technicians will work with grounding wiring associated with the liquid hydrogen engine cutoff sensor system, as well as adjust the configuration of components within Discovery's point sensor box."

Comments

good luck :)

[thhamm]

(HAL 9000 on Discovery): "I am fully operational, and all my circuits are functioning perfectly. I have the highest enthusiasm for this mission."

Re:good luck :)

[thhamm]

And the ISS needs this flight too. badly. (they`ve run out of beer).

Re:good luck :)

[thhamm]

This is an ordinary L-unit: L

Without it, space travel would be nothing more than the dream of a mad man.

But this is the L-unit we removed from the Shuttle: l

I call it sabotage!

What now?

[bassgoonist]

This time the check engine light won't turn off...

Re:What now?

[kzinti]

Actually, it's more like the check engine light went on, but by the time you get the car to the mechanic, it's gone off and won't come on again.

In the shuttle's case, they can't repeat the problem. The theory now is that it only occurs when the tanks are loaded (and thus at cryo temperatures versus ambient).

Re:What now?

[Xaroth]

This time the check engine light won't turn off...

That's what electrical tape is for: to cover that light so you don't have to look at it any more.

Re:What now?

[Mark Hood]

That's what electrical tape is for: to cover that light so you don't have to look at it any more.

My father has experience in this matter. He once got a lift in a chinook helicopter and noticed over the pilot's shoulder that about half the warning lights in the cockpit were flashing. Being an engineer, he was concerned that it might be overdue a maintenance cycle, and asked the pilot about them. He replied 'oh, they're all minor, nothing to worry about'.

On the way back a couple of days later, he realised it was the same helicopter and the same pilot, but this time none of the warnings were flashing. 'So you found time for a service then?' he joked.

'Oh, I just got sick of the flashing lights, so I unscrewed the bulbs' he replied.

My father never worked out if he was joking or not...

Mark

PS I know it's not rocket science, but it's a great story :)

Get Them In The Air

[rk_cr]

I'm afraid that NASA shuttles will never get in the air again, due to the now incredibly high standards of NASA. The last problem may have been pretty big, but we can't turn off every shuttle launch just because it's not absolutely perfect.

Believe me, I want the astronauts to survive. But you also have to understand that going into space is dangerous. Things go wrong even in the most tested of scenarios. The astronauts know the risk.

The best thing that could happen...

[Anonymous Coward]

would be for some sort of non-lethal disaster to happen that severely damages/destroys the Shuttle but doesn't kill the crew. Perhaps some accident on the landing, or some sort of problem before launch but where they can get the crew off safely but still destroys the shuttle.

This way, we can finally get rid of the pork politics blasphemeies known as the Shuttle and the ISS and start investing money into a real, sustainable manned space program, instead of this ridiculous horse and pony show.

Re:The best thing that could happen...

[Y-Crate]

I think a lot of fans of the space program (and NASA employees as well) would love to see all of the Shuttles just fall apart in storage ala the Bluesmobile at the end of The Blues Brothers

Sadly, that will not happen, and any damage sustained during a flight would give more ammunition to those who believe NASA's funding should be eliminated altogether (or at least the funding for the manned side of things).

Another accident would simply doom the organization. When Challenger was lost, NASA was allowed some breathing room to rework itself as an organization. When Columbia disintegrated, it was the death knell for the shuttle program much sooner than anyone could have expected or hoped for. Anything else at this point, would likely put the entire organization back another 10 years, if they were even allowed to fly people up again.

NASA is running on its last chance here. All of the remaining shuttles will be decommissioned in 5 years. Period. The CEV is being worked on at an accelerated pace. No more of the "Yeah, that one part failed during a test and it will take 18 months to fabricate a new one, so everyone involved with the project can sit on their hands while we make this thing" like we had with the previous attempts to remaking the shuttle without really having technology ready to see it through.

Some would like to argue that private industry could do manned exploration better. I'm sure they could do launches quite nicely, but no company is anywhere close to having an orbital craft. And good luck on finding me a private company that will drop a few billion on pure research for the sake of knowing more about our galaxy.

Re:The best thing that could happen...

[Rei]

A couple things:

1) Destroying the shuttle, like the parent hoped for, would be disastrous. Not only would we see NASA cuts, as others have suggested, but there'd be another multiyear downtime in which nothing occurs: Including the development of a replacement vehicle.

2) The focus on complete re-usability.

What focus on complete reusability? The external tank is disposable.

3) The reliance on the tiles alone, without any ablative shielding

Ablatives are just as problematic for a reusable craft. Ablatives, too, can chip, and have to be reapplied with care and detailed inspection. They're even more problematic around moving parts, btw, than tiles and RCC panels are. Lastly, they weigh more, something that the shuttle simply couldn't afford.

The shuttle's main problem isn't something that you stated: it is having such a huge reentry vehicle. A huge, *dense* reentry vehicle (dense because it doesn't have big empty voids where large drained fuel tanks would normally be). This means a lot of energy to dissipate over a proportionally small surface area. Even with its low beta entry (it takes almost an hour from the LEO deorbit burn to landing), well, you know how much heat it has to deal with.

Heat problems don't scale linearly. A material with 500MPa tensile strength at 500 degrees may be down to 200MPa at 600, 40MPa at 700, 4MPa at 800, and molten shortly thereafter. It becomes a *lot* harder the higher the temperatures you have to deal with; your options quickly become quite limited.

3) tiles alone

The shuttle's TPS (Thermal Protection System) involves two different types of tiles, reinforced carbon-carbon leading edges, and insulating blankets.

4) fragile to the point of being delicate

I doubt you could damage a tile without tools short of throwing it as hard as you can onto a hard surface (in which case, you'd probably just chip it). They're nothing like steel or even aluminum in terms of resistance to damage, but they're not nearly as delicate as people around here pretend, especially given their density. The problem is, when you go hundreds to thousands of meters per second (depending on where you're at in ascent/descent), even raindrops become fierce impactors.

The biggest problems with the tiles are that they have to be repaired at all. Attaching a tile (or RCC panel, for that matter) to a metal frame, securely so that it won't fall off, when the metal is expanding at a different rate than the tile, is no simple task (it was resolved with the SIP - Strain Isolation Pad). You can't have any significant loose spaces, because at hypersonic speeds cracks tend to funnel in plasma like a blowtorch. The tiles have to endure the large vibrational loads of ascent as well. Consequently, it's a huge task to make sure that they're all A) intact, and B) securely attached.

5) Why use a vehicle in LEO to launch a satelite

It's called a stage. Even vehicles that we "launch from the ground" typically use a separate stage to get to GEO. Now, why you'd want to use a *manned* craft for the first few stages is a good question; however, the shuttle usually doesn't deal with such missions, and leaves them to things like Atlas and Delta rockets.

Rename it

[Winterblink]

I think it might be time to rename this shuttle Longhorn

A step in the right direction...

[d3m057h3n35]

with plans to launch the orbiter spaceward on July 26

I think we all needed that clarified. I can never guess what those wacky people at NASA will think of next!

The Second Round of a Difficult Situation for NASA

[ausoleil]

There are three possible outcomes to the launch attempt, only one of them is completely positive:

1. Discovery launches Tuesday during the launch window and has a routine and successful mission. After that, there will be plenty of time to determine the root cause of the sensor issue.

2. The weather does not co-operate or another tenchnical glitch surfaces, causing Tuesday's attempt to be scrubbed. NASA is hounded in the press for being unable to manage their spacecraft, when in fact they are doing exactly that according to their safety protocols, which have been generally tightened post-Columbia.

3. Disaster. Unthinkable and possibly the end of an American manned space presence until the Crew Exploration Vehicle is completed and launched in the next decade.

The Space Shuttle is an aging flying compromise that has been updated as much as possible, and it is what NASA has been given to work with. I almost expect Outcome #2, given their justifiable prudence in halting launches when they are not 100% satisfied that the system is as operationally ready as they can make it. NASA may be criticized for delays, but when seven lives and a multi-billion dollar spacecraft are on the line, not to mention all of their political capital, once can understand why they do what they do.

Bottom line is that all eyes will be back on the Cape come Tuesday morning. Godspeed Discovery.

Hmm. Ground wire... hydrogen tank...

[RetiredMidn]

I'll watch from a distance, thank you.

Re:It's amazing how many electrical problems

[vtrac]

Thanks, I'll be sure to forward this info to NASA.

How did it come to this?

[iShaman]

For god's sake, how did it come to this, anyway?!? 30 years in and the STS program is still considered an experimental program with experimental vehicles.

I remember cutting out time magazine stories about Congress funding the space station in 1983! This is probably very simplistic thinking, but we could've taken the money we wasted on ISS in the 80's and designed a much more dependable shuttle fleet where loose wiring didn't mess the whole launch up.

And we're still talking about a Mars mission?1? Step by step, folks...not all at once.

Having just finished a test sensor application...

[Jtheletter]

I can totally relate to the problems and frustrations of improper (or in my case, disconnected) grounds in a system causing bad readings and being difficult to debug.

Now what I can't imagine is how many times more difficult that is when true "ground" ends up being over 100 kilometers away!

Have they learned nothing?

[linuxwrangler]

This sounds hauntingly familiar. In the first disaster NASA had simply gotten used to seeing some burn-through on the o-rings to the point that it was "normal", in the second disaster they had seen foam and ice come off the orbiter but nothing bad had happened so far.

In the third disaster they couldn't find the cause of the fuel sensor problem so they declared that only three were needed and launched anyway.

Bob Cowell writes an excellent column in Computer magazine. In one column titled "Murphy Was Wrong" he points out that unlike Murphy's Law, things usually go right in spite of a myriad of glitches. In fact, they go right so often that people start ignoring the warning signs. It usually takes a severe or multiple failures to cause an actual catastrophe.

If something is failing it is failing for a reason. Don't launch till you know the cause and for gods sake don't "solve" the problem by simply rewriting the rules to say that it's OK for a "critical" system to fail.

As cool as the space exploration and the shuttle are, it may be time to say that the program has utterly failed to meet its goals, will never be able to meet its goals, and that we should cut our losses, take the information we have learned from the shuttle program, and move forward on a replacement.

Consider that the stated goal for the shuttles was 100 missions each. Unfortunately that's pretty close to the tally for the whole fleet. Oh, and there is that little annoying fact that 40% of the orbiters have crashed killing all aboard.