SpaceX Crew Dragon Departs, Carrying NASA Astronauts Toward Home

Two astronauts who took the first commercial trip to orbit have left the International Space Station. They are scheduled to return home on Sunday.

The astronauts, Robert L. Behnken and Douglas G. Hurley, traveled to the space station in May aboard a Crew Dragon capsule built and run by SpaceX, the private rocket company started by Elon Musk.

The Crew Dragon undocked from the space station at 7:35 p.m. Eastern time on Saturday, with brief thruster firings pushing the spacecraft back.

As the capsule backed away from the station, Mr. Hurley thanked the current crew of the space station and the teams on the ground that helped manage their mission.

“We look forward to splashdown tomorrow,” he said.

If the weather conditions remain favorable, it will splash down in the Gulf of Mexico off Pensacola, Fla., at 2:48 p.m. on Sunday, NASA announced.

The capsule is now performing a series of burns to move away from the station and then line up with the splashdown site.

For much of the trip, Mr. Behnken and Mr. Hurley will be sleeping. Their schedule sets aside a full night of rest.

Any return journey that exceeds six hours has to be long enough for the crew to get some sleep between undocking and splashdown, Daniel Huot, a NASA spokesman, said in an email.

Otherwise, because of the extended process that leads up to undocking, the crew would end up working more than 20 hours straight, “which is not safe for dynamic operations like water splashdown and recovery,” Mr. Huot said.

Just before a final burn that will drop the Crew Dragon out of orbit on Sunday afternoon, it will jettison the bottom part of the spacecraft, known as the trunk, which will then burn up in the atmosphere.

At re-entry, the Crew Dragon will be traveling at about 17,500 miles per hour. Two small parachutes will deploy at an altitude of 18,000 feet when the spacecraft has already been slowed by Earth’s atmosphere to about 350 miles per hour. The four main parachutes deploy at an altitude of about 6,000 feet.

Once the capsule splashes in the water, it is expected to take 45 to 60 minutes to pluck them out.

The storm complicated where splashdown could take place. At the splashdown site, winds must be less than 10 miles per hour for the capsule to land safely. There are additional constraints on waves, rain and lightning. In addition, helicopters that take part in the recovery of the capsule must be able to fly and land safely.

The first landing opportunity will aim for only the primary site, Pensacola. If weather there is inconsistent with the rules, the capsule and the astronauts will remain in orbit for another day or two, and managers will consider the backup site, which is Panama City.

Spacecraft can safely return to Earth in either environment.

During the 1960s and 1970s, NASA’s Mercury, Gemini and Apollo capsules all splashed down in the ocean while Soviet capsules all ended their trips on land. Russia’s current Soyuz capsules continue to make ground landings, as do China’s astronaut-carrying Shenzhou capsules.

When Boeing’s Starliner capsule begins carrying crews to the space station, it will return on land, in New Mexico. SpaceX had originally planned for the Crew Dragon to do ground landings, but decided that water landings, employed for the earlier version of Dragon for taking cargo, simplified the development of the capsule.

After launch, re-entry through Earth’s atmosphere is the second most dangerous phase of spaceflight. Friction of air rushing past will heat the bottom of the capsule to about 3,500 degrees Fahrenheit. A test flight of the Crew Dragon last year successfully splashed down, so engineers know the system works.

A successful conclusion to the trip opens the door to more people flying to space. Some companies have already announced plans to use Crew Dragons to lift wealthy tourists to orbit.

In the past, NASA astronauts launched on spacecraft like the Saturn 5 moon rocket and the space shuttles that NASA itself operated. After the retirement of the space shuttles in 2011, NASA had to rely on Russia, buying seats on the Soyuz capsules for trips to and from orbit.

Under the Obama administration, NASA hired two companies, SpaceX and Boeing, to build spacecraft to take astronauts to the space station. NASA financed much of the work to develop the spacecraft but will now buy rides at fixed prices. For SpaceX, the trip by Mr. Behnken and Mr. Hurley — the first launch of astronauts from American soil since the last space shuttle flight — was the last major demonstration needed before NASA officially certifies that the Crew Dragon is ready to begin regular flights.

The astronauts are Robert L. Behnken and Douglas G. Hurley, who have been friends and colleagues since both were selected by NASA to be astronauts in 2000.

Author: ApnayOnline is an oline news portal which aims to provide latest trendy news around the Asia

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