The International Space Station has been left by two astronauts who made the first commercial trip into orbit. They ‘re set to go home on Sunday. The astronauts, Robert L. Behnken and Douglas G. Hurley, flew to the space station in May in a SpaceX-built and operated Crew Dragon spacecraft, the private aerospace company founded by Elon Musk.
The Dragon crew undocked at 7:35 p.m. from the space station Eastern time on Saturday, driving back the spacecraft with brief thruster firings.
As the capsule backed away from the station, Mr. Hurley thanked the space station’s current crew and on-the-ground teams who helped manage their mission.
“Tomorrow we are looking forward to splash-down,” he said.
If the weather stays good it should splash off at 2:48 p.m. in the Gulf of Mexico off Pensacola, Fla. NASA reported Sunday.
A successful return will open up further journeys aboard the spacecraft to and from the orbit for potential astronaut teams, and probably space tourists.
Isaias is expected to sweep through weekend along Florida’s Atlantic coast. NASA and SpaceX have seven splashdown sites in the Gulf of Mexico and the Atlantic, but the storm’s track ruled the Atlantic out of the three.
“We ‘re sure the teams on the ground are of course watching it even better than we are,” Mr. Behnken said during a news conference on Friday, “and we’re not going to leave the space station without any decent landing opportunities in front of us, decent splashdown conditions in front of us.”
How do I watch astronauts return?
The coverage of the undocking by NASA Television will continue through splashdown. It can be seen in the video player below.
What happens after they have left the station?
The capsule now performs a sequence of burns to push away from the station and reconnect with the splashdown site afterwards.
Mr. Behnken and Mr. Hurley will be asleep for much of the trip. Their calendar sets aside a whole night of rest.
Any return trip that reaches six hours will be long enough for the crew to get some sleep between undocking and splashdown, NASA spokesman Daniel Huot said in an email.
Otherwise, the crew would end up working more than 20 hours straight because of the extended process leading to undocking, “which isn’t safe for dynamic operations such as water splashdown and recovery,” Mr. Huot said.
Just before a final burn on Sunday afternoon that will drop the Crew Dragon out of orbit, it will jettison the lower part of the spacecraft, known as the trunk, which will then burn up in the atmosphere.
The Crew Dragon will travel at around 17,500 miles per hour upon re-entry. Two small parachutes will be deployed at an altitude of 18,000 feet when the Earth’s atmosphere has already slowed the spacecraft to some 350 miles per hour. The four primary parachutes are deployed at an altitude of approximately 6000 feet.
Once the capsule splashes in the water, plucking them out is expected to take 45 to 60 minutes.
Why does the departure impact Isaias?
The storm has complicated where splashdown could occur. At the splashdown site, winds for the capsule to land safely need to be less than 10 miles per hour. Waves, heat, and lightning are further restrictions. In addition, helicopters involved in capsule recovery must be able to safely fly and land.
Only the primary site, Pensacola, will target for the first landing chance. The capsule and astronauts will stay in space for another day or two if the weather is incompatible with the rules, and managers will call the contingency site, which is Panama City.
Back to Earth
The SpaceX Crew Dragon is expected to splash off on Sunday near Florida, but Hurricane Isaias may change those plans.
Is Landing on water or on land safer?
In either scenario Spacecraft can safely return to Earth.
NASA’s Mercury, Gemini, and Apollo capsules all splashed in the ocean during the 1960s and 1970s, while Soviet capsules all ended their journeys on land. Russia ‘s current Soyuz capsules continue to make landings in the ground, as do the Shenzhou capsules carrying astronauts from China.
When the Starliner capsule of Boeing starts carrying crews to the space station, it will return to New Mexico on land. Originally, SpaceX had designed ground landings for the Crew Dragon but decided that water landings, used for the earlier version of Dragon to take cargo, would simplify the capsule production.
Why is the return voyage an important part of the first flight of the Crew Dragon?
The second most dangerous phase of spaceflight is re-entry through Earth’s atmosphere after launch. Friction from air that rushes past will heat the capsule’s bottom to about 3,500 degrees Fahrenheit. A Crew Dragon test flight sprinkled successfully last year so engineers know the system is working.
A successful end to the trip opens the door to more people flying out into space. Some firms have already revealed plans to use Crew Dragons to carry rich tourists into space.
NASA astronauts have flown on rockets in the past, such as the Saturn 5 moon rocket and the space shuttles that NASA operated itself. NASA had to rely on Russia after the 2011 removal of the space shuttles, purchasing seats on the Soyuz capsules for trips to and from orbit.
NASA recruited two firms under the Obama administration, SpaceX and Boeing, to develop spacecraft to carry astronauts to the space station. NASA has funded much of the spacecraft construction research, but will now be purchasing trips at fixed rates. For SpaceX, Mr. Behnken and Mr. Hurley’s trip — the first American soil launch of astronauts since the last space shuttle flight — was the last big demonstration required before NASA officially certifies that the Crew Dragon is able to start daily flights.
Who are those astronauts?
The astronauts are Robert L. Behnken and Douglas G. Hurley, who were friends and colleagues when NASA named them both as as astronauts in 2000.
Both men have experience as military test pilots and both flew on space shuttle flights twice before, but this is the first time they have served on a mission together. Mr. Hurley took off on the last flight of the space shuttle in 2011.
They were among the astronauts chosen in 2015 to work with Boeing and SpaceX on commercial space vehicles that were being built by the companies. They had been given the first SpaceX flight in 2018.
What did the astronauts do aboard the space station?
Originally, the mission was to last for only two weeks, but Mr. Behnken and Mr. Hurley ended up staying at the space station for a longer and busier period. Because of repeated delays by SpaceX and Boeing, when the Crew Dragon and its two passengers docked, NASA ended up short-handed, with only one astronaut, Christopher J. Cassidy, aboard the space station.
They remained at the space station for two months, helping Mr. Cassidy with chores. Mr. Behnken and Mr. Cassidy did four spacewalks to complete the installation of new space station batteries. Mr. Hurley assisted with the operation of the robotic arm at the station.
The men have also contributed to low earth orbit research studies. We assisted with the use of a shower head in a test of water droplet formation in the space station’s low gravity environment, and another that used fruit punch and foam to look at how to handle space fluids. They also assisted in installing new equipment inside the station that will be used in future studies.
Mr. Cassidy and two Russian astronauts, Anatoly Ivanishin and Ivan Vagner, will remain aboard the station. All three will remain aboard until October when they will be replaced by another crew of one American and two Russian astronauts.
When are next Crew Dragon flights, and who are they going to be carrying?
The Crew Dragon’s first operational flight starts no earlier than late September. It will take three NASA astronauts to the space station — Michael S. Hopkins, Victor J. Glover, and Shannon Walker — and one Japanese astronaut, Soichi Noguchi,.
Tentatively planned for February 2021 the second operational flight will bring two NASA astronauts, Robert S. Kimbrough and K. Megan McArthur; Japanese Akihiko Hoshide; and The European Space Agency ‘s Thomas Pesquet.
Ms. McArthur and Mr. Behnken are married.