Space Shuttle Status Report

[Astronuc]

The Canaveral site was also chosen since there are not large populated areas downrange that would be endangered in a catastrophic failure.   The Texas coast could have also been a suitable site, but close to the Gulf of Mexico, it also has high humidity - and Florida is down range.  For dryness, West Texas would be great, but then the Texas coast and Florida are downrange of that location.

[Astronuc]

NASA Could Attempt Shuttle Launch Sunday  (Cross your fingers!)

By MARCIA DUNN, AP Aerospace Writer

CAPE CANAVERAL, Fla. - NASA said Thursday that it will not make another attempt to launch space shuttle Discovery until at least Sunday — and even that is a "really optimistic good-luck scenario."

Deputy shuttle program manager Wayne Hale said the space agency still probably faces several days of troubleshooting to figure out what caused the faulty fuel-gauge reading that forced the cancellation of Wednesday's launch.

The only way the shuttle would be able to fly on Sunday is "if we go in and wiggle some wires and find a loose connection," said Hale, who conceded that was unlikely to work.

Wednesday's liftoff would have been the first shuttle flight in 2 1/2 years since the grounding of the space program after the Columbia accident. With little more than two hours to go and the astronauts on-board, the flight was canceled because a fuel gauge read full when it should have read empty.

Hale said the space agency had 12 engineering teams around the country trying to figure out why, but so far they haven't solved the problem.

"I wish I had more answers for you," he said.

He wouldn't rule out the chance of launching Discovery in July, and NASA officials have no immediate plans to move Discovery from the launch pad back to its hangar, which would require more days of delay.

NASA has until the end of the month to send the shuttle and its seven astronauts to space on their 12-day mission or it must wait until September. The launch timing is dictated by both the position of the space station and NASA's desire to hold a daylight liftoff so it can photograph the spacecraft during its climb to orbit and watch out for possible damage.

"I'm not ready to give up on a July window," Hale said. "We still have several days ahead of us."

On Wednesday, shuttle managers found themselves on the defensive, explaining why they pressed ahead with the launch when the same type of potentially fatal problem with the fuel gauges cropped up during a fueling test just three months ago and was accepted as an "unexplained anomaly."

The space agency requires all four of its hydrogen-fuel gauges to be working to ensure that the main engines shut off in space at just the right moment. If the engines shut down too soon or too late because of erroneous gauge readings, the results could be catastrophic. For instance, the engines could rupture if they kept running after the tank sprang a leak and ran out of fuel.

Some engineers had pushed for further testing at the pad before committing to a liftoff, but were overruled by top managers who concluded that the replacement of cables, the electronics box and the tank itself was ample.

However, even if NASA had conducted another fueling test in June, Hale said it's unclear whether the fuel gauge would have malfunctioned the way it did in a checkout test: Instead of showing an empty tank, the gauge kept showing full.

The delayed launch came just a day after an embarrassing turn for NASA, when a plastic cockpit window cover fell off the shuttle and damaged its fragile thermal tiles before the spacecraft had even taken off.

Wednesday's launch delay disappointed space buffs across the country. From Cape Canaveral, where congressmen and astronaut families had come to witness the awe-inspiring sight of a rocket launch, to museums coast to coast where schoolchildren had gathered, the postponement of the long-awaited return to space was disheartening.

"I wanted to see it really, really, really bad," groaned 8-year-old Michael Schamtin of Sherwood, Ore., who had waited for liftoff at the Oregon Museum of Science and Industry.

When the shuttle finally does take off, the astronauts will test new techniques for inspecting and repairing cracks and holes similar to the damage that doomed Columbia in 2003.

In the 2 1/2 years since Columbia broke apart on its return to Earth, NASA has worked to fix its "safety culture," which the accident investigators concluded broke down during the flight.

NASA also has concentrated on making the external fuel tank safer by reducing the risk that foam insulation, ice or other debris will break off at launch. The gauge that caused trouble on Wednesday is in the external fuel tank, but was unrelated to any of the safety modifications.

[Astronuc]

OK - scrap Sunday - 

NASA's shuttle launch off till late next week

CAPE CANAVERAL, Fla. (Reuters) -  NASA said on Friday that the earliest it could launch the space shuttle Discovery on the first shuttle mission since the 2003 Columbia accident would be late next week, after liftoff was postponed two days ago because of a technical problem.

The U.S. space agency said it had formally halted the countdown as engineers searched for the cause of the fault that prevented Discovery's launch.

"We are backing out, standing down from the countdown, which means the next launch attempt will be late next week at the earliest," a NASA spokesman told reporters. More details would be revealed at a news conference late Friday.

Discovery had been due to blast off on Wednesday afternoon from Cape Canaveral in Florida, the first shuttle mission since its sister ship Columbia broke apart over Texas in February 2003, killing the seven crew. But a faulty hydrogen fuel sensor forced NASA to call off the launch two hours before liftoff.

Early on Friday, technicians removed propellants from the shuttle's onboard power generators, NASA spokeswoman Jessica Rye said.

"Technically, in a perfect world and if there was an easy fix, we could get back into the countdown (Friday) night, but we need to let the teams go and figure out the problem and how to fix it," Rye said.

During a typical countdown, removing the onboard propellants would reset a shuttle's three-day launch countdown clock back to the starting position.

HYDROGEN SENSORS

NASA engineers still do not know why one of Discovery's four hydrogen sensors failed a routine test as the clock ticked down toward liftoff and the crew members, led by veteran astronaut Eileen Collins, were being strapped into their seats. Engineers are working through around 200 possible scenarios.

The sensors are designed to make the shuttle's three main engines shut down before fuel runs out.

A premature shutdown of the engines could force the spacecraft to make an emergency landing or prevent it from reaching its desired orbit.

Although launch delays are common, the glitches preventing Discovery from getting off the launch pad are receiving heightened scrutiny because the shuttle is the first to fly since NASA grounded the fleet for safety upgrades following the loss of Columbia.

Columbia's wing was damaged during launch by a piece of foam insulation that fell off its fuel tank. As it flew through the atmosphere for landing, superheated gases blasted into the wing and destroyed the ship.

NASA has until July 31 to launch Discovery, a deadline dictated by its planned rendezvous with the International Space Station and a new requirement that shuttle launches take place in daylight so cameras will have clear views of liftoff.

The next launch window begins on Sept. 9. NASA had planned to use the September launch window to fly the space shuttle Atlantis on the agency's second post-Columbia mission.

"I'm not ready to give up on the July window at this point," deputy shuttle program manager Wayne Hale said on Thursday. "We still have more than two weeks ahead of us, so that's the way we're headed."

He added, however, that flight planners already were trying to figure out if a three-day launch window in November could be expanded to accommodate Atlantis' flight if Discovery had to take the September launch slot.

[Astronuc]

Factors limit shuttle's launch times (Orlando Sentinel)

Fuel requirements and the sun's angle reduce the opportunities Discovery has to lift off.

By Robyn Shelton | Sentinel Staff Writer
Posted July 15, 2005


The targeted window for Discovery's planned launch Wednesday ran from 3:51 to 3:56 p.m.  You might wonder: Why that particular slice of time?

NASA's launches are affected by many factors. One is the shuttle itself.

Because the ship carries a limited amount of fuel, Discovery needs to launch when it can reach its destination -- the international space station -- without running out.

To do this, NASA targets the launch within five minutes of the moment that Earth's rotation carries the shuttle's launchpad into the plane of the station's orbit.

Put another way: "It's when the shuttle can launch to reach the station with the available propellant," said NASA spokesman Rob Navias at Johnson Space Center in Houston.

Because every shuttle now is going to the station, they all must lift off during those small windows of opportunity.

In the past, missions could have much longer windows if they weren't going to the outpost.

The good news is that there's a chance to fly to the station every day. The bad news is that many days are unusable for other reasons.

One potential problem is something engineers call the "beta angle," which refers to how the sun would hit the station and shuttle when they are joined together.

The shuttle can't get too much sunshine, and therefore too much heat, while it's docked at the outpost. So there are periods of time when the angle is unfavorable for a shuttle visit.

Other limitations come from new safety measures.

The space agency has imposed lighting requirements on at least the first two launches after the shuttle Columbia disaster. This means that the ship must fly in daytime so cameras can record the launch to check for any debris that might strike the shuttle.

In addition, the astronauts record the separation of the shuttle's tank once they reach orbit. To do so, the tank needs to be dropped on the sunlit side of Earth.

All these constraints limit the number of available launch days. For example, the entire month of August is ruled out because of the lighting requirements, Navias said.

[Skyjim]

Understand that I spent a long time on the shuttle program and loved the vehcile and the people who fly it - but after Columbia, I lost faith in NASA's ability to recognize flight safety issues before they kill crews.  Now there are memos leaking from supposed administration sources specifying only 15 more shuttle flights. 

OK, fair enough, though it strikes me as a half-measure.  I personally thought we should've grounded permanently after Columbia and spent the money on a cargo system for the remaining ISS hardware, jumpstarting the next human system,  and buying Soyuz, Progress, and ATV flights as gapfillers.  We'd be two years into that effort now, instead of staggering towards return to flight with aging issues still dogging us.

So, what can they do with 15 flights?  8 are needed to get to the so-called "core complete", with a completed power system/truss and Node 2 in place.  You need a flight to get Columbus up, THREE to get Kibo, it's logistics module, exposed facility, and RMS up, one for Science power platform arrays for the Russian segment and possibly one logistics flight can also boost the cupola.  I've heard something about the cancellation of the Centrifuge module (the one I personally thought was most relevant to deep-space mission design), but assume it goes up too, and you've used up all the remaining 7 flight slots without flying a Hubble servicing mission, which seems to be something Griffin wants to do. That is including ZERO MPLM flights among that 7, and kids, the ISS architecture relied on the MPLMs to get large equipment racks both up and down.   The administration is finally asking for some modification to the Iran Nonproliferation Act to allow purchase of Soyuz/Progress services.

SO - my question is, what gets dropped?  What can be transferred to Progress or ATV?  How much equipment already built cannot fit through the aft hatch of Zvezda  (or the PMAs in the U.S. segment) and would require an MPLM (or analog) to get it aboard the station?  How much smaller are those other hatches and mating adapters?  How much gear originally planned for return via MPLM is at risk of "stranding" since we obviously are not going to have the kind of downmass capability represented by several MPLM flights between now and the end of shuttle?  What chance is there of flying some items on other uncrewed systems?  Could ATV be adapted to dock with the lower node hatches by installing  a Kurs sytem on Node 2 and going to U.S. standard hatches and CBMs? 

Inquiring minds want to know! 

Jim

[yale]

Is it possible that the flights are simply "contract fullfilment" missions.. without regard to whether they actually accomplish needed activities?

[Skyjim]

That is precisely my fear, Yale - just enough to physically put the modules up, not enough to actually derive any benefits from the investment they represent.  I don't think Kibo, Destiny, or Columbus can be fully utilized sans the kind of cargo capability  represented by those MPLMs.  But I'm not certain of my facts regarding how many racks for each were planned for transport via MPLM.  All I know is that it appears we are about to hang the partners out to dry here.

Looks like the transfer hatches on the Progress and ATV are 800mm in diameter.  Don't have a number yet for the big Node/lab hatches or the PMAs...

Jim

[Astronuc]

NASA Aims for Shuttle Launch Tuesday
By MARCIA DUNN, AP

CAPE CANAVERAL, Fla. (July 21) - NASA will try to launch Discovery on the first shuttle mission in more than two years next Tuesday, after tracing last week's fuel gauge failure to, most likely, an electrical grounding problem lurking inside the spacecraft.

Shuttle program manager Bill Parsons said Wednesday the only way to thoroughly check the system is to fuel Discovery and have all its equipment running.

''We believe the best way to go through this is to do a countdown,'' he said. ''If the sensors (gauges) work exactly like we think they will, then we'll launch on that day. If anything goes not per the plan that we've laid out in front of us, then we'll have a scrub and we'll have to talk about it.''

In what would be an almost certainly controversial move in the wake of the 2003 Columbia tragedy, NASA may also proceed with the liftoff if the fuel gauge problem recurs but is considered well understood. That would mean revoking a launch rule requiring all four hydrogen fuel gauges at the bottom of Discovery's external tank to be working properly, and instead relying on just three out of four.

That looser three-out-of-four rule was thrown out after the 1986 Challenger launch explosion.

The fuel gauges are intended to keep a shuttle's main engines from shutting down too early or too late after liftoff, both potentially disastrous situations. Only two of the four are needed to ensure safety, but ever since the Challenger accident, NASA has required all four to be operating.

Parsons said there are considerable ''safety nets'' to protect against launching a seriously flawed spacecraft, if an exception to the fuel gauge rule is made at the last minute.

''Right now, we think we have eliminated all the common causes that we believe could do this and we've done everything we possibly could on the vehicle,'' he told journalists at an evening news conference.

Technicians plan to swap some pins and wiring near the electronics box that is associated with the four hydrogen fuel gauges, to better understand what happened last week.

Discovery's countdown was halted with just two hours remaining before liftoff last Wednesday when one of the four fuel gauges malfunctioned. It was the same type of problem that marred a fueling test of Discovery back in April, with a different external tank.

Despite a week of exhaustive scrutiny by hundreds of engineers, NASA has been unable to pinpoint the precise cause or location of the failure, and an electrical grounding problem somewhere in the aft fuselage is considered the most likely cause. The space agency is holding out hope that the grounding problem can be traced to interference from shuttle equipment in the next few days, but will aim for a Tuesday launch even if the mystery persists.

Among the many shuttle parts suspected of possibly causing electromagnetic interference are newly installed heaters on the external fuel tank. The heaters are meant to prevent the kind of lethal damage suffered by Columbia at liftoff.

''We have a great amount of work in front of us to get us through this and get us ready,'' Parsons said. ''But we've all agreed that this work is doable and that it all takes us to a launch on the 26th.''

The countdown is set to begin Saturday for a Tuesday morning launch.

Discovery and its crew of seven will fly to the international space station to drop off supplies and make repairs, and will test inspection and patching techniques for the type of damage that doomed Columbia.

If Discovery isn't flying by the beginning of August, the flight will be bumped to September to ensure a daylight launch and good surveillance photography throughout the shuttle's ascent.

[Skyjim]

OK!  Despite my jaundiced view of the safety of the system (especially as operated by a NASA  hierarchy that I don't believe is CAPABLE of changing itself where shuttle ops is concerned) I'm paradoxically quivering with Go Fever as badly as anybody.   There is still hardware I touched in those SSMEs and I'll sweat ascent like I always do, especially that first 120 seconds - as I've said elsewhere, I really hate those damned SRBs!  I have huge confidence in the SSMEs.  (A bit prejudiced, I know, but they aren't going to fail with no warning!!)

Sounds like they may have a plausible scenario for the sensor glitch - and with the wiring swaps, they can hopefully confirm the location of the fault during tanking Monday night if it recurs.  If nothing acts funny, I'd be nervous, but as anybody who has ever chased ground faults in a complex electrical system can attest, you don't always see the same problem repeating itself.  Nothing makes one crazier than an intermittent glitch!  Hopefully everything is hunky-dory as soon as they turn off the new heaters, which would tend to confirm what appears to be their leading fault tree candidate mechanism.

This is precisely the sort of issue that we can expect to see more and more of until the end of shuttle ops, though. I don't think that any reliability numbers for the shuttle system mean anything at all given the demonstrated aging of the wiring and the huge number of potential faults that can develop.  We're not going to spend the money to gut the vehicles and rewire them completely - nor should we.  That leaves us likely facing many more glitches like this one over the next 5 years.    There are some which can wind up with an orbiter lost, sometimes in a survivable bailout situation for the crew, sometimes with catastrophic consequences like a Lox-rich shutdown of an SSME, the concern with the ECO sensors. 

Anybody remember Eileen Collin's FIRST mission as Commander?  That was the Chandra deployment mission, and a wiring short on Columbia damn near shut down 2 SSMEs right off the pad.  That was the incident that led to the fleet wiring inspections - though it has always been acknowledged that there was some wiring that was simply not accessible for physical inspection.  Had they lost even one SSME in the first few seconds of flight, that is generally an orbiter-in-the-ocean scenario.  Crew has to bail out, since ditching a shuttle has been shown to be non-survivable for them.  The payload and possibly the SSMEs and thrust structure are likely going to wind up impacting the crew compartment on deceleration even if the chines don't dig in and immediately tear the structure apart.

We're flying an aging, hideously complex system whose operational lifetime per orbiter was originally specified as 10 years or 100 flights.  Just because flight rates are low doesn't mean that things like wiring aren't degraded from environmental factors.  Even Endeavour is 13 years past her first flight and exceeding design operational age.  I fervently hope that we can keep slapping adequate fixes on problems as they are found - but I dread the reality that could slap us in the face at any time - a fatal accident from a previously unforeseen and unhinted-at fault that doesn't reveal itself in minor glitches first. 

Jim

[Astronuc]

OK!  Despite my jaundiced view of the safety of the system (especially as operated by a NASA  hierarchy that I don't believe is CAPABLE of changing itself where shuttle ops is concerned) I'm paradoxically quivering with Go Fever as badly as anybody.   There is still hardware I touched in those SSMEs and I'll sweat ascent like I always do, especially that first 120 seconds - as I've said elsewhere, I really hate those damned SRBs!  I have huge confidence in the SSMEs.  (A bit prejudiced, I know, but they aren't going to fail with no warning!!)

We're flying an aging, hideously complex system whose operational lifetime per orbiter was originally specified as 10 years or 100 flights.  Just because flight rates are low doesn't mean that things like wiring aren't degraded from environmental factors.  Even Endeavour is 13 years past her first flight and exceeding design operational age.  I fervently hope that we can keep slapping adequate fixes on problems as they are found - but I dread the reality that could slap us in the face at any time - a fatal accident from a previously unforeseen and unhinted-at fault that doesn't reveal itself in minor glitches first. 

I hear you, Jim!  I hope once they lift-off, it's a smooth, safe and successful round trip.

The materials on those craft, if not replaced are old.  I too worry about the age factor.

I'll be keeping every appendage crossed!

 

[remcook]

Although it seems a bit bizar, it looks like NASA is just going to have to be 'lucky' to fly the shuttle enough time to fulfill its duties... :-/

[Astronuc]

Countdown Resumes for Discovery's Launch

CAPE CANAVERAL, Fla. (July 23) - NASA restarted its countdown clocks on Saturday in preparation for a second attempt to return its space shuttle fleet to flight following the 2003 Columbia accident.

"We are all eagerly looking forward to a successful launch," said NASA test director Pete Nickolenko.

Liftoff of space shuttle Discovery is targeted for 10:39 a.m. EDT on Tuesday. The seven-member crew arrived at Florida's Kennedy Space Center on Friday for final flight preparations.

NASA had planned to launch Discovery on July 13 but a critical fuel sensor failed a routine preflight test and managers called off the flight.

After more than a week of tests, engineers were unable to duplicate the glitch but did find some slight problems with how some parts of the sensor system were electrically grounded. Technicians made adjustments to three groundings.

Attempts to trace possible electromagnetic interference so far have not been successful, but NASA plans to continue tests once the shuttle's fuel tank is filled with 500,000 gallons of cryogenic liquid hydrogen and liquid oxygen on launch day.

"The battery of testing and analysis that we've done so far leads us to believe we are confident that we've got good sensors," Nickolenko said. "The true proof will be when we perform the tanking operation for the launch attempt Tuesday morning."

This will be the fourth flight for Collins.

[Astronuc]

NASA to Launch Even if Problem Recurs
Lift-Off Scheduled for Tuesday Morning
By MARCIA DUNN, AP

CAPE CANAVERAL, Fla. (July 24) - NASA said Sunday it will launch the first space shuttle flight in 2 1/2 years even if Discovery is plagued by the same fuel gauge problem that halted the previous countdown two weeks ago.

Discovery is set to lift off Tuesday at 10:39 a.m.

Deputy shuttle program manager Wayne Hale said the fuel gauge problem has been a vexing one — engineers still don't know exactly what caused it — and he's repeatedly asked himself, "Are we taking care enough to do it right?"

"Based on the last 10 days' worth of effort, the huge number of people and the tremendous number of hours that have been spent in testing and analysis, I think that we're coming to the right place," he said.

At an evening news conference, Hale and other NASA officials found themselves defending the decision to launch with a fuel gauge failure. They stressed that they will proceed with a liftoff only if the problem is well understood and involves the gauges in question — anything else will result in a postponement.

NASA's own launch rule — in place since the 1986 Challenger disaster — requires that all four hydrogen fuel gauges in the external tank be working properly. Going with three out of four would result in a "deviation" of the rule, Hale told reporters.

"I am committed — and I think the whole team is committed — to doing this in a safe manner," Hale said. "I think we're all still struggling a little bit with the ghost of Columbia and therefore we want to make sure we do it right."

NASA Administrator Michael Griffin said he supports the decision and even hopes the problem recurs to further pinpoint the source of the trouble. He acknowledged that the public might perceive that the space agency is rushing to launch, but insisted it was the right technical judgment.

"These are rather arcane matters, I would admit. They're rather difficult and sometimes they don't always present well," Griffin said. "But in the long run, I think if it's the right thing, we can explain it to you, and you want us doing what's right, not what necessarily is obvious or popular."

Workers last week repaired faulty electrical grounding inside Discovery in hopes that would solve the fuel gauge problem that thwarted the first launch attempt on July 13. One of the four gauges failed a routine test two hours before the scheduled liftoff. Technicians also swapped the wiring between the troublesome fuel sensor and another one to better understand the issue if it reappears Tuesday.

The same type of problem occurred back in April during a fueling test, and was written off as an "unexplained anomaly."

The fuel gauges are needed to prevent the main engines from shutting down too soon or too late during liftoff, in the event of an extreme problem like a leaking tank. The first scenario could result in a risky, never-attempted emergency landing; the second could cause the engine turbines to rupture and, quite possibly, destroy the spacecraft.

Only two fuel gauges are needed to avoid such dangerous situations, but NASA normally requires all four to be working at liftoff for redundancy.

Hale conceded there is no way to know with 100 percent certainty that more fuel gauges will not conk out on the shuttle's climb to orbit, if NASA launches with only three functioning ones. But that would involve stacking up multiple failures, he noted, "and the odds become kind of in the acceptable risk category that we have to go fly with."

One person at Sunday's mission management meeting, which was led by Hale, had concerns about the fuel gauge issue and expressed them in an anonymous suggestion box. Hale said the matter was addressed and, in the end, the group came to a consensus — "I would almost say unanimity" — that the game plan was good.

NASA has just one week to launch Discovery and its crew of seven to the international space station, before putting off the mission until September.

The space agency is insisting on good lighting in order to see any signs of the type of launch damage that crippled Columbia. The opportunity for good photography, both at Cape Canaveral and over the North Atlantic when the fuel tank separates nearly nine minutes after liftoff, diminishes in August and is unacceptable until Sept. 9.

Forecasters, meanwhile, put the odds of good launch weather Tuesday at 60 percent, with rain and clouds as the main concerns. What's more, the weather at the overseas emergency landing sites is not looking good at all.

Hale refused to put his own odds on the chance of a liftoff.

"My observation is that when the weather is good, you have vehicle problems. If the vehicle works, you have weather problems," he said, smiling. "Since we have some weather concerns, I'm confident the vehicle is going to be OK."

[Astronuc]

Discovery's Fuel Sensor Passes Pre-Launch Test
By MIKE SCHNEIDER, AP

CAPE CANAVERAL, Fla. (July 26) - A fuel sensor system on Discovery's external tank passed initial tests early Tuesday as NASA finished fueling the space shuttle for the first launch attempt since the doomed Columbia flight 2 1/2 years ago.

NASA officials monitored the fuel sensor system on the gigantic external tank throughout the entire three-hour fueling process to make sure the sensors functioned properly. A faulty reading of a sensor caused a scrub on July 13 as astronauts were boarding the spacecraft.

"All the sensors are performing as expected,'' said NASA commentator Jessica Rye.

Discovery and a crew of seven were set to blast off for the international space station at 10:39 a.m. EDT. The forecast improved early Tuesday to odds of good launch weather at 80 percent, compared to 60 percent the day before.

NASA had the paperwork ready to go in case the equipment trouble reappeared and the space agency's managers decided to press ahead with the launch with just three of the four sensors working, a deviation from a rule instituted after the 1986 Challenger explosion.

Only two sensors are needed to do the job. But ever since NASA's return to space in 1988, the space agency has decreed that all four have to work to proceed with launch.

NASA Administrator Michael Griffin called the deviation "an acceptable risk.''

"Actually, it's quite a low one,'' Griffin told The Associated Press on Monday.

The fuel sensors are designed to prevent the main engines from running too long or not long enough, in case the fuel tank is leaking or some other major breakdown occurs. An engine shutdown at the wrong time could prove catastrophic, forcing the astronauts to attempt a risky emergency landing overseas, or leading to a ruptured engine.

Over the past few days, NASA rewired two of the sensors to try to diagnose the trouble and repaired faulty electrical grounding aboard Discovery in hopes that would solve it.

"We have addressed everything we know on the shuttle that can go wrong that we have the technology to fix,'' Griffin said. "Some things simply are inherent to the design of the bird and cannot be made better without going and getting a new generation of spacecraft.''

But a retired agent in NASA's inspector general office, Joseph Gutheinz, said the space agency does not appear to have learned its lesson with Columbia. Accident investigators criticized NASA's tendency to downplay risks and discourage engineers from speaking up.

"It is clear to me that NASA continues to put mission over safety,'' Gutheinz said. "I fear that if NASA is wrong this time, as they were for Apollo 1, Challenger and Columbia, manned space missions may be halted for a very long time in the United States.''

The launch promised not only to be an appraisal of changes in NASA's safety culture, but also a test of a redesigned fuel tank that was altered after the Columbia disaster to minimize debris falling off it.

Discovery has only until the beginning of August to fly to the space station on a 12-day supply and repair mission; the next launch opportunity will not come until Sept. 9.

The launch window is dictated by the space station's position and NASA's insistence on a daylight liftoff to provide good views for the more than 100 cameras that will be checking for any Columbia-type launch damage.

While in orbit, Discovery's crew will inspect the most vulnerable areas of the spacecraft, using a new 50-foot, laser-tipped boom. They also will practice repairing samples of deliberately damaged thermal tile and panels.

[Skyjim]

OK, we're out of the T-9:00 hold and rolling towards launch with no apparent problems.



LET'S DO LAUNCH!!!!


Jim