Less than a week after staying at the space station, Boeing's new passenger spacecraft CST-100 starliner returned to earth on the afternoon of May 25 local time. It landed completely in the desert of New Mexico with the help of parachutes and airbags The successful landing put an end to starliner's key test flight, which demonstrated the aircraft's ability to launch into space, dock with the space station and finally return safely.
Boeing's starliner capsule, shaped like a chewing gum, was built in cooperation with NASA to launch its astronauts to the international space station. The mission is part of NASA's commercial crew program (CCP), which challenges private companies to build space taxis and send people to low earth orbit. But before NASA lets its staff ride on the aircraft, the space agency hopes starliner can prove that it can complete all the actions to the ISS - no one is on it.
With this landing, this unmanned test flight -- called oft-2 -- has ended, and starliner has completed every major step it has to complete. The capsule was successfully launched into orbit on May 19 (local time in the United States) and entered space by Atlas V rocket; Approaching and docking with ISS on May 20; On the afternoon of the 25th, the docking with the space station was undocked before going home. However, it was not a completely smooth flight. Throughout the mission, starliner encountered some problems with its various thrusters. These tiny engines are used to manipulate and drive the aircraft to fly in space. However, none of these problems proved fatal to the flight, and starliner was able to complete oft-2 as planned.
The road to the launch is also very rough. The name of this test flight -- oft-2 actually refers to orbital flight test-2. This is because it is a remake of the same test flight that Boeing tried to carry out as early as 2019. In December that year, Boeing launched starliner without a crew, when it sent it into space with another atals V rocket. However, a software failure on starliner led to the wrong launch of thrusters after the capsule separated from the rocket. Finally, the spacecraft entered the wrong orbit. This problem prevented starliner from reaching the space station, and Boeing was unable to demonstrate the spacecraft's ability to dock with the ISS. Boeing had to take the spacecraft home early and land the capsule at the White Sands Missile Launch Site in New Mexico, where the starliner landed.
Boeing tried to launch starliner again last summer, but just hours before takeoff, the company found that more than a dozen propellant valves were stuck and could not be opened normally, so it stopped the countdown. Boeing has not solved these problems until now, and the company said it may redesign the valve in the future. But now, two and a half years after the initial failed flight, starliner has finally shown that it can launch and dock with ISS autonomously - it will have to perform this key function repeatedly when someone is on board.
Landing is also a key task for starliner. In order to demonstrate these capabilities of this flight, the capsule decoupled from the ISS at 2:36 p.m. Eastern time this afternoon, and then began to fly slowly around the space station, and then kept a distance from the laboratory in orbit. At 6:05 EDT, starliner used its onboard thrusters to slow itself down and out of orbit, allowing it to enter orbit on the earth's surface. Soon after, the aircraft passed through the earth's atmosphere and experienced temperatures as high as 3000 degrees Fahrenheit. Starliner then uses a series of parachutes to slow it down, and then lands on the white sand's airbag to help cushion the landing. This marks starliner's second successful landing, as Boeing has demonstrated the aircraft's landing capability in its first failed test flight in 2019.
"This landing was at 5:49 p.m. (US) Central time, almost the sixth day of the mission," NASA communications officer Brandi Dean said in the live broadcast of the landing. "A beautiful landing in Baisha tonight."
However, people were worried about the landing because starliner had several problems with its propeller during the whole flight. When the capsule was launched into space last week, two of the 12 thrusters starliner used to insert itself into the correct orbit failed. Boeing pointed out that the pressure drop in the cabin caused the thruster to cut off in advance. Eventually, starliner's flight control system turned to a backup propeller in time to put the capsule into orbit as planned. However, the same thrusters also need to take the starliner out of orbit, but although there are two thrusters that can't work normally, they seem to work as planned.
Other errors occurred throughout the flight. Several different small thrusters used to operate the starliner during docking also failed due to low cabin pressure. However, this does not hinder the docking of the capsule with the ISS. "We have a lot of redundancy and it really doesn't affect the rendezvous operation at all. In addition, the Boeing team also noticed that some starliner thermal systems used to cool the spacecraft showed ultra-low temperatures, which the engineering team had to manage during the docking," ssteve stich, NASA CCP project manager, said at a press conference after the docking
Starliner still achieved many goals when docking with ISS. Astronauts on the space station opened starliner's hatch at the weekend, entered the aircraft and retrieved the cargo brought to the space station. The module has brought about 600 pounds of cargo back to Earth - and rocket man Rosie, a mannequin riding in starliner to simulate human riding.
Now, with starliner back on earth, Boeing and NASA still have a lot of work to do. They will call this manned flight test in the coming months, and determine whether it is ready for the manned flight this year. Although this success will be a huge milestone for Boeing, it has fallen far behind SpaceX, another CPP supplier of NASA. SpaceX has conducted five manned flights for NASA using its manned dragon spacecraft, which carried the first passengers in 2020.
But if starliner is approved for manned flight, NASA will eventually have what it has always wanted: two different American companies have the ability to bring institutional astronauts into orbit.