Boeing Starliner Landing: What You Need to Know


Boeing’s test of a spacecraft, the CST-100 Starliner, is being cut short because a problem with its internal clock right after launch on Friday put it into the wrong orbit. The capsule, which was built to resume launches of astronauts from the United States, was not able to dock with the International Space Station because of the error.

The capsule, which looks much like the Apollo spacecraft that took NASA astronauts to the moon 50 years ago, is scheduled to parachute to White Sands Missile Range in New Mexico at 7:57 a.m. Eastern time on Sunday. NASA Television will broadcast coverage beginning at 6:45 a.m.

There is also a backup time of 3:48 p.m. Eastern time if the landing cannot be attempted on the first try.

The Starliner consists of two pieces: the capsule where astronauts will be sitting, and a service module that contains thrusters and other systems that are not needed for landing. A thruster firing will cause Starliner to fall back into the atmosphere. The service module is to fall into the Pacific Ocean while the capsule is to cross over Mexico’s Baja peninsula north and then land in New Mexico, its touchdown softened by parachutes and airbags.

For NASA, attempting to put a capsule down on land is unusual. All previous landings of its capsules — the Mercury, Gemini and Apollo programs of the 1960s and 1970s — were in the ocean. After all, you might be safer diving into water than an expanse of sand.

Russian astronauts have always landed on solid ground, and that approach offers advantages. Salt water corrodes metal, which would complicate plans to reuse Starliner capsules for future missions. Also, a capsule hitting an ocean wave at the wrong angle could sink. (That is what happened during testing of Apollo capsules, requiring a revamping of the design.)

The Starliner capsule currently in orbit is scheduled to be used again for a future mission carrying astronauts.

Quite simply: Starliner got the time wrong.

When the spacecraft separated from the Atlas 5 rocket that lifted it to space, an incorrect clock caused it to start firing its thrusters and try to get into the position and orientation where it thought it should be.

“She thought she was later in the mission,” Jim Chilton, senior vice president of the space and launch division at Boeing, said during a news conference on Saturday, “and being autonomous, started to behave that way.”

That caused it to use much more propellant than was expected. Its communications antennas also were not pointed in the correct position, which meant it did not immediately receive corrective commands from Boeing’s flight controllers on Earth. Because of the initial problem, not enough propellant remains to rendezvous and dock with the space station.

“If I knew, it wouldn’t have happened” Mr. Chilton said. “We were surprised.”

The spacecraft’s software set its clock based on the time it received from the Atlas 5 rocket before launch, and it is still too early to tell how it pulled the incorrect information, said Mr. Chilton. He added that the problem was with the Boeing software, not with the rocket, which was built and operated by the United Launch Alliance.

This flight did not have anyone on board, but NASA and Boeing officials insist that if astronauts had been in the capsule, they would have been safe. The astronauts might even have been able to take over manual control and send the spacecraft on the proper path.

Flight controllers were able to send Starliner the correct time. They then performed a couple of thruster firings to raise its orbit to a circular one 155 miles above the surface. That is lower than the International Space Station, which is at an altitude of about 250 miles.

Mr. Chilton said the spacecraft’s propulsion, navigation and life support systems are now operating well.

“We do have a healthy spacecraft,” said Jim Bridenstine, the NASA administrator. “There are many good milestones we have been able to achieve.”

Boeing and NASA will investigate what went wrong and fix it. NASA officials said it was too early to know whether Boeing will be required to fly another crewless mission to dock with the space station or whether it would be able to put astronauts on the next flight as currently planned.

Although the current mission could not perform all of its tasks, if landing is successful tomorrow, the two portions of greatest danger to astronauts — launch and return to Earth — will have been demonstrated.

NASA still hopes to carry astronauts to orbit again in the first half of 2020, and has hired two companies to take astronauts to the space station, Boeing and SpaceX. Both have encountered hurdles and delays.

The problem with Boeing’s Starliner does not directly affect SpaceX’s Crew Dragon capsule. But that company still has to complete tests of its parachute and conduct an in-flight test of its abort system, currently scheduled for Jan. 11, before it is ready to carry astronauts.

Boeing had been aiming for a demonstration flight taking astronauts to the space station in the first half of 2020. But the problems on Friday’s uncrewed test may lead to further delays.

NASA has already talked to Russia about buying additional seats on the Soyuz rockets, which have been the only transportation available to astronauts to and from the International Space Station since 2011.



Sahred From Source link Technology

Be the first to comment

Leave a Reply

Your email address will not be published.


*