Discovery enters final countdown

[Salem6]

By Paul Rincon
BBC News science reporter, at the Kennedy Space Center





The Discovery orbiter is just minutes away from making the first shuttle flight since the Columbia disaster.

Its crew are in their seats, the hatch is closed and the spaceship's external tank is filled with the cryogenic fuels needed to power its huge engines.

US space agency engineers have had no repeat of the fuel sensor problem that scrubbed the 13 July launch attempt.

Lift-off is scheduled for 1039 local time (1439 GMT; 1539 BST) from the Kennedy Space Center in Florida.

Proving doubters wrong

Tuesday's launch is the culmination of two-and-a-half years of arduous work to ensure Nasa learnt the safety lessons of the Columbia disaster, which cost the lives of seven astronauts.

SHUTTLE RETURN TO FLIGHT

Mission known as STS-114
Discovery's 31st flight
17th orbiter flight to ISS
Payload: Raffaello Multi-Purpose Logistics Module
Lift-off: 1039 EDT, 26 July
Location: Kennedy Space Center, Launch Pad 39B
Discovery crew: Collins, Kelly, Noguchi, Robinson, Thomas, Lawrence and Camarda



Columbia broke up as it re-entered the Earth's atmosphere on 1 February 2003. Super-heated gases entered a hole punched in the wing during take-off by a suitcase-sized chunk of foam from the external tank, tearing the vehicle apart.

"There are some doubters out there who think we won't fly again, so it's our job to make this happen and show everyone involved that we can do this and do it safely," shuttle vehicle manager Stephanie Stilson told the BBC News website.

The three-hour process of filling the external fuel tank with super-cold hydrogen and oxygen began just after midnight local time.

Engineers have since been monitoring closely the engine cut-off (Eco) sensors in the tank's liquid hydrogen compartment. One of these sensors, which act like fuel gauges to tell the shuttle's computers when the tanks run dry, failed during routine checks in the lead-up to the 13 July lift-off attempt.

Nasa says Discovery will fly only if all these sensors work properly, or if a sensor fails in a way that Nasa can understand. But a go-ahead to launch if the latter occurs may involve changing a flight rule that four sensors need to be working.

'No pressure'

Agency officials are adamant they are proceeding responsibly and that their decision is informed by the painstaking efforts to isolate the problem.

"There is absolutely no pressure to launch; we're looking for the best possible situation to go," Nasa chief Dr Mike Griffin told the BBC News website.

The chances of bad weather preventing Tuesday's launch have been reduced down to 20%.

Discovery's crew members, led by Commander Eileen Collins, are due to do their traditional walkout at 0649 EDT (1049 GMT; 1149 BST), after which they will proceed to pad 39B, where the shuttle will blast off on its 12-day mission to the International Space Station.

The launch will be attended by First Lady Laura Bush, Florida governor Jeb Bush and family members of astronauts killed in both the Columbia and Challenger disasters.

Discovery will take parts and supplies to the ISS and test new safety features such as a repair-kit for heat shield tiles and a 50ft-long robotic arm that will inspect the shuttle for damage in space.

Discovery is due to touch down at Kennedy Space Center on 7 August at 0546 EDT (0946 GMT; 1046 BST).



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[Salem6]

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[Salem6]

By Paul Rincon
BBC News science reporter, at the Kennedy Space Center

Nasa has launched its first manned space mission in two-and-a-half years.

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Space shuttle Discovery blasted off on its 12-day flight at 1039 local time (1539 BST) from the Kennedy Space Center in Florida.

It roared up into a bright blue sky to the cheers of spectating astronaut families and US space agency staff.

Discovery's crew will test safety measures brought in after the Columbia accident in 2003 and resupply the International Space Station.

US space agency officials said they were happy with the launch, despite the sighting of what appeared to be some debris falling from the vehicle moments after it cleared the pad.

They said they would wait for detailed photo analysis to be done before coming to any conclusions about the structural integrity of Discovery.

According to plan

"On behalf of the many millions of people who believe so deeply in what we do, good luck, God speed and have a little fun up there," Nasa launch director Mike Leinbach told Commander Eileen Collins and her crew just before lift-off.

SHUTTLE RETURN TO FLIGHT

Mission known as STS-114
Discovery's 31st flight
17th orbiter flight to ISS
Payload: Raffaello Multi-Purpose Logistics Module
Lift-off: 1039 EDT, 26 July
Location: Kennedy Space Center, Launch Pad 39B
Discovery crew: Collins, Kelly, Noguchi, Robinson, Thomas, Lawrence and Camarda



It was Nasa's second go at a lift-off in the current launch window.

An earlier attempt on 13 July had to be scrubbed because of the failure of a fuel sensor; but the problem did not recur on Tuesday and the countdown proceeded without interruption.

Collins and were crew were strapped in and the hatch closed as launch controllers went through the pre-flight checks.

On cue, the orbiter raced skyward leaving a huge exhaust plume in its wake.

The separation of solid boosters and external tank all occurred without incident; and after eight-and-a-half minutes, Discovery shut down its engines to enter the planned preliminary orbit.

A series of thruster firings will gradually raise its altitude over the next couple of days.

"We know that the folks back on the planet Earth are just feeling great right now and our thanks to everybody for all the super work that's been done over the past two-and-ahalf-years to get us flying again," Collins told mission control in Houston not long after launch.

Camera watch

"Take note of what you've seen today," said Nasa chief Dr Mike Griffin.

"Of the power and majesty of launch, of course; but also the competence and professionalism, the sheer gall, the pluckiness, the grittiness of this team that pulled this programme out of the depths of despair two-and-half-years ago and made it fly."

Nasa says it has learnt the safety lessons of the Columbia disaster, which cost the lives of seven astronauts, and has made this the most scrutinised shuttle flight ever.

Columbia broke up as it attempted to re-enter Earth's atmosphere.

Super-heated gases entered a hole punched in the wing during take-off by a suitcase-sized chunk of foam from the external tank, tearing the vehicle apart.


The launch was watched by First Lady Laura Bush and Florida Governor Jeb Bush



Nasa had positioned more than 100 cameras both on the ground and in the air to capture as much detail as possible on Discovery's ascent into orbit.

Shuttle managers expect to have all the imagery in and checked over by day six of the flight. If there is an issue over the debris sighted at launch, engineers should have ample information to judge the seriousness of the situation.

US President George W Bush watched the launch on television.

"I thank the men and women of Nasa who have dedicated themselves to putting our space program back on track," he said in a statement.

"Our space programme is a source of great national pride, and this flight is an essential step toward our goal of continuing to lead the world in space science, human spaceflight, and space exploration."

Discovery will take parts and supplies to the ISS and test new safety features such as a repair-kit for heatshield tiles and a 15m-long robotic arm that will inspect the shuttle for damage in orbit.

Discovery is due to touch down at Kennedy Space Center on 7 August at 0546 EDT (0946 GMT; 1046 BST).



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