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Raumfahrt - SpaceX CRS-3 Cargo-Start verschoben auf 18.April - UPDATE

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14.04.2014

Monday's scheduled launch of a robotic SpaceX cargo craft to the International Space Station will proceed despite the failure of a backup electronics box for the station's truss system, NASA says.
Mission managers said they would be able to work around the problems caused by the faiure. "We're good to go," Michael Suffredini, NASA's space station program manager, said during a Sunday news conference.
Suffredini said a spacewalk to replace the box is being planned for April 22, after the SpaceX delivery.
SpaceX, a California-based company founded by billionaire Elon Musk, has a $1.6 billion contract with NASA to deliver supplies and other payloads to the space station. For the next supply mission, about 4,600 pounds (2,100 kilograms) of cargo has been packed inside a Dragon capsule for launch atop a two-stage SpaceX Falcon 9 from Cape Canaveral Air Force Station in Florida.
Liftoff is scheduled for 4:58 p.m. ET Monday, with the chances of acceptable weather set at 80 percent or better. The only concern is the potential for increasing clouds at the launch site.
Redundancy recovered
The electronics box, known as a modulator-demodulator, failed to respond to commands on Friday — and NASA determined that it had to be replaced. The box serves as the backup for another modulator-demodulator that's operating normally. Either box can be used to send commands to components on the space station's main truss, including the robotic arm's rail car system, the station's external cooling system and the movable joints for the power-generating solar arrays.
Suffredini said the main concern about going ahead with Monday's launch was to keep the station's solar arrays in the proper position while avoiding a conflict with the Dragon's arrival and berthing. Astronauts will have to use the station's robotic arm to bring the unmanned capsule in for its berthing on Wednesday, and if both boxes were out of commission, that would have affected the ability to move the arrays.
"We're able to essentially get back the redundancy we need."
NASA planners found a way to keep the arrays in a fixed position during the Dragon's visit, Suffredini said.
"We're able to essentially get back the redundancy we need because we can position the solar arrays such that we're OK," he told reporters.
The plan for the April 22 spacewalk to replace the electronics box is still being fine-tuned, Suffredini said. The operation is expected to take about two and a half hours, and it's considered one of the space station's "Big 12" routine maintenance tasks. Suffredini said replacing the box is "one of the simplest [tasks] we can do."
Critical items on Dragon
Suffredini noted that the Dragon payload included critical items — including a replacement spacesuit and other spacesuit components that would reduce the potential for water leaks like the one that almost drowned an Italian spacewalker last year.
The capsule is also bringing up supplies for the crew, scores of scientific experiments, five nanosatellites and the legs for the station's Robonaut 2 android.
After the supplies are unloaded, the station's astronauts will load it back up with about 3,600 pounds (1,650 kilograms) of cargo for return to Earth. The Dragon will then unhook from the station and descend to its splashdown and recovery from the Pacific Ocean.
This mission is particularly notable because it's the first tryout of a system that could eventually enable the Falcon 9's first stage to fly back to a landing pad. The Falcon 9 due for launch on Monday has been outfitted with deployable landing legs, and the first stage will restart its engines after separation to slow its descent toward the Atlantic Ocean.
SpaceX will try to recover the first stage for potential reuse, said Hans Koenigsmann, the company's vice president of mission assurance. But he cautioned reporters that the procedure was "experimental," and gauged the chances of success at 30 to 40 percent.
Quelle; NBC
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SpaceX Resupply Mission 'Go' For Monday Launch

International Space Station Program officials, the international partners and representatives of SpaceX agreed Sunday to proceed with Monday’s scheduled launch of the SpaceX Falcon 9 rocket and its Dragon cargo craft on the company’s third commercial resupply mission to the orbital laboratory. Launch is targeted for Monday at 4:58 p.m. EDT from Launch Complex 40 at Cape Canaveral Air Force Station, Fla.
Quelle: NASA
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Update: 22.00 MESZ
CRS-3 Update
Today’s launch has been scrubbed due to a Helium leak on Falcon 9’s first stage. A fix will be implemented by the next launch opportunity on Friday April 18, though weather on that date isn’t ideal. Check back here for updates.
Quelle: SpaceX
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Update: 16.04.2014
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SpaceX on track for Friday launch try

Irene KlotzSpaceflight Correspondent 16 April 2014 15:24

Sen—Space Exploration Technologies will make another attempt Friday, 18 April, to launch its Falcon 9 rocket and Dragon capsule on a resupply run to the International Space Station for NASA.

A launch attempt Monday from Cape Canaveral Air Force Station in Florida was canceled an hour before liftoff.

“Preflight checks detected that a helium valve in the stage separation pneumatic system was not holding the right pressure. This meant that the stage separation pistons would be reliant on a backup check valve,” SpaceX said in a statement issued Wednesday.

“No issue was detected with the backup valve and a flight would likely have been successful, but SpaceX policy is not to launch with any known anomalies,” the statement said.

The rocket has been returned to a horizontal position so technicians can replace the faulty valve.

The next launch try will be at 3:25 p.m. EDT/1925 GMT, but the weather could be a problem. Air Force meteorologists are predicting a 60 per cent chance of rain, and thunderstorms could force another delay.

The rocket will carry a Dragon capsule loaded with food, science experiments and gear for the space station, which flies about 250 miles (about 400 km) above Earth.

If the Falcon 9 launches as planned, the capsule would reach the station on Sunday.

As part of the flight, SpaceX plans to test technology it has been developing to recover and reuse its rockets.

The Falcon 9’s first stage carries extra fuel for two more burns after the upper-stage and Dragon capsule separate. The idea is to slow the rocket’s descent and position it for a soft touchdown on the ocean.

The booster also has four landing legs to help stabilize the vehicle. 

Quelle: SEN

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A Falcon 9 rocket that was supposed to launch Monday has been rescheduled for Friday afternoon.

The launch is now set for 3:25 p.m. Friday after a first-stage helium leak scrubbed the first attempt.

There is a 40 percent chance of favorable weather at launch time, with a chance of showers and thunderstorms that could violate launch constraints.

If there is a second scrub, SpaceX will attempt to launch Saturday, April 19 at 3:02 p.m.

NASA said this is an instantaneous launch time. That means it must happen for the rocket to launch and the Dragon capsule to catch up to the International Space Station within two days.

Despite a computer problem at the International Space Station last week, NASA gave the go-ahead over the weekend for SpaceX to launch its rocket later Monday.

The launch will also dictate when a contingency spacewalk will be performed to replace a failed multiplexer-demultiplexer aboard the ISS.

The rocket will deliver the Dragon capsule, with 2.4 tons of cargo for astronauts, to the space station.

Once there, astronauts there will unload the cargo, which includes research experiments, food and four high-definition cameras that will stream live video of Earth for online viewing.

The Falcon 9 rocket being used in this launch has been modified with new, 60-foot-long legs designed to help the rocket land back on Earth after launch, making the spacecraft reusable for future launches, like the space shuttles before it.

The plan is that after the Dragon capsule separates and heads for the ISS, the first stage of the rocket will make a soft splashdown in the Atlantic Ocean.

SpaceX said it wants to test the landing legs in the ocean first to improve precision, but eventually the private company wants to land the rocket near the launch pad. The company could save millions of dollars by reusing the rocket instead of having to build a new one for each launch.

SpaceX issued the following statement Wednesday morning:

NASA and SpaceX have confirmed Friday, April 18 for the next launch attempt for the Falcon 9 rocket to send the Dragon spacecraft on the company's third commercial resupply mission and fourth visit to the space station. Launch is targeted for 3:25 p.m. ET. The launch will be webcast live at www.spacex.com/webcast beginning at 2:45 p.m. ET.
 
A launch on Friday results in a rendezvous with the space station on Sunday, April 20 and a grapple at 7:14 a.m. ET.
 
During Monday’s launch attempt, preflight checks detected that a helium valve in the stage separation pneumatic system was not holding the right pressure. This meant that the stage separation pistons would be reliant on a backup check valve.
 
No issue was detected with the backup valve and a flight would likely have been successful, but SpaceX policy is not to launch with any known anomalies. We have brought the vehicle back to horizontal and are replacing the faulty valve, as well as inspecting the whole system for anything that may have contributed to the valve not working as designed.
Quelle: NEWS13
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Update: 20.04.2014
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SpaceX successfully launches The Dragon with supplies for International Space Station

The SpaceX company returned to orbit Friday, launching fresh supplies to the International Space Station after more than a month’s delay.

The Dragon cargo ship will reach the orbiting lab on Sunday — Easter morning. That pushes urgent spacewalking repairs to Wednesday; NASA wants a bad computer replaced before something else breaks.

This was the second launch attempt this week for SpaceX.

NASA’s commercial supplier was foiled by a leaky rocket valve Monday. The valve was replaced, and the company aimed for a Friday liftoff despite a dismal forecast. Storms cleared out of Cape Canaveral just in time for the mid-afternoon launch into overcast skies.

 

The unmanned cargo ship contains 2½ tons of station supplies, including material originally intended for the spacewalking repairs.

A critical backup computer failed outside the space station last Friday. The primary computer is working fine, but numerous systems would be seriously compromised if it broke, too. A double failure also would hinder visits by the Dragon and other vessels.

“It’s imperative that we maintain” backups for these external command-routing computer boxes, also called multiplexer-demultiplexers, or MDMs, said flight director Brian Smith said Friday. “Right now, we don’t have that.”

 

NASA decided late this week to use the gasket-like material already on board the space station for the repair, instead of waiting for the Dragon. Astronauts trimmed the thermal material Friday to fit the bottom of the replacement computer, and inserted a fresh circuit card.

Much-needed food is also aboard the Dragon, along with a new spacesuit and spacesuit replacement parts. NASA wants all these things at the space station as soon as possible.

The shipment is close to five weeks late. Initially set for mid-March, the launch was delayed by extra prepping, then damage to an Air Force radar and, finally on Monday, the rocket leak.

 

The space station’s six-man crew watched the launch via a live TV hookup; the outpost was soaring 260 miles above Turkey at the time of ignition. Video beamed down from Dragon showed the solar wings unfurling.

Earlier, as the countdown entered its final few hours, NASA’s space station program manager Mike Suffredini said an investigation continues into the reason for last summer’s spacesuit failure. The helmet worn by an Italian astronaut filled with water from the suit’s cooling system, and he nearly drowned during a spacewalk.

 

Routine U.S. spacewalks are on hold until engineers are certain what caused the water leak. The upcoming spacewalk by the two Americans on board is considered an exception because of its urgent nature; it will include no unnecessary tasks, just the 2½-hour computer swap.

NASA is paying the California-based SpaceX — Space Exploration Technologies Corp. — and Virginia’s Orbital Sciences Corp. to keep the orbiting lab well stocked. Russia, Japan and Europe also make periodic deliveries.

Unlike the other cargo carriers, the Dragon can bring items back for analysis. Among the science samples going up on the Dragon and slated to return with it in a month: 200 fruit flies and their expected progeny, and germs collected from stadiums and sports arenas, as well as such notables as America’s Liberty Bell and Sue, the T. rex fossil skeleton at Chicago’s Field Museum.

 

Scientists will study the hearts of the returning flies — as many as 3,000 are expected for the trip home, if the males and females do as they should. The germ samples, once back on Earth, will be compared with duplicate cultures on the ground.

Staying up there — for as long as the space station lives — will be new legs for NASA’s humanoid, Robonaut. The indoor robot has been in orbit for three years, but only from the waist up.

Quelle: SE

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