Bob Behnken and Doug Hurley are preparing for a Gulf of Mexico splashdown on Sunday in the Crew Dragon spacecraft.
The Crew Dragon capsule is completing maneuvers to bring the spacecraft out of orbit and splashdown in the sea under parachutes.
beautiful day for a splashdown from space
The first astronaut trip to orbit by a private company is coming to an end. The passengers are two NASA astronauts — Robert L. Behnken and Douglas G. Hurley — but it could be a first step to more people going to space for a variety of new activities like sightseeing, corporate research and satellite repair.
This flight of the Crew Dragon capsule is being operated by SpaceX, the rocket company started by Elon Musk, as part of NASA’s efforts to turn over to private enterprise some things it used to do.
NASA has hired two companies — SpaceX and Boeing — to provide transportation of astronauts to and from the International Space Station, and SpaceX was the first to be ready to take astronauts to orbit, launching Mr. Behnken and Mr. Hurley in May.
After 63 days on the space station, Mr. Behnken and Mr. Hurley reboarded the Crew Dragon and undocked from the space station on Saturday evening.
The capsule and its passengers will land in the Gulf of Mexico off Pensacola, Fla., on Sunday. Splashdown is scheduled for 2:48 p.m. Eastern time. It will be the first water landing by NASA astronauts since 1975, when the agency’s crews were still flying to and from orbit in the Apollo modules used for the historic American moon missions.
SpaceX’s mission controllers told the astronauts that the spacecraft’s status, after a series of maneuvers to prepare it for landing, was “really good for entry, no health issues at this time.”
Earlier concerns about the Isaias storm system working its way up the Florida Atlantic coast prompted the selection of the Pensacola splashdown site. SpaceX officials on Sunday just before 2:30 p.m. described the weather around the landing zone as “very calm.”
Watch the return of the astronauts
NASA Television’s coverage will continue through splashdown. You can also watch it in the video player above. Video below shows the spacecraft’s departure from the space station on Saturday night.
What will happen as the spacecraft begins to land?
On Saturday, the Crew Dragon performed a series of thruster burns to move away from the space station and then line up with the splashdown site.
Before leaving orbit on Sunday, the spacecraft jettisoned its bottom half, known as the trunk, which will no longer be needed. That exposes the heat shield that protects the capsule and astronauts during re-entry.
“Oh yeah, we felt it,” Mr. Hurley said after the maneuver was confirmed on the ground.
One more thruster burn of about 11 minutes in length was completed after 2 p.m. Eastern time, which will cause the capsule to drop out of orbit, headed toward its landing site at sea.
Is it safer to land on water or on land?
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.
The last water landing by NASA astronauts occurred in July 1975 at the end of the Apollo-Soyuz mission, during which an American crew aboard an Apollo module docked in orbit with two Soviet astronauts aboard a Soyuz capsule.
While the crew splashed down safely, a problem with the Apollo spacecraft during re-entry caused fumes from rocket propellant to fill the capsule, causing breathing and eye problems for the astronauts.
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. Elon Musk, the founder of SpaceX, further explained the reasoning on Twitter early on Sunday:
What do astronauts experience during a water landing?
Returning from the free-fall environment of orbit to the normal forces of gravity on Earth is often disorienting for astronauts. A water landing adds the possibility of seasickness.
During a news conference on Friday, Mr. Hurley said he had read some of the reports by the Skylab astronauts. “There was some challenges post splashdown,” he said. “Folks didn’t feel well, and you know, that is the way it is with a water landing, even if you’re not deconditioned like we’re going to be.”
Mr. Hurley acknowledged that vomiting would not be unexpected.
“There are bags if you need them, and we’ll have those handy,” he said. “We’ll probably have some towels handy as well. And you know, if that needs to happen, it certainly wouldn’t be the first time that that’s happened in a space vehicle.”
What have the astronauts been doing since they undocked?
Sleeping mostly.
Following a series of thruster firings to put the spacecraft on track with the landing site, the astronauts’ schedule included a full night of rest. The capsule even completed one of its maneuvers while the astronauts are supposed to be sleeping.
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.
On Sunday morning, the astronauts were greeted with a wake up message sent from Earth by their two sons.
Just before noon, the astronauts began to put their SpaceX spacesuits back on as they completed preparations for landing.
Why is the return trip an important part of the Crew Dragon’s first flight?
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.
Who are the astronauts?
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.
Both men have backgrounds as military test pilots and each has flown twice before on space shuttle missions, although this is the first time they have worked together on a mission. Mr. Hurley flew on the space shuttle’s final mission in 2011.
In 2015, they were among the astronauts chosen to work with Boeing and SpaceX on the commercial space vehicles that the companies were developing. In 2018, they were assigned to the first SpaceX flight.
What have the astronauts been doing aboard the space station?
Originally, the mission was to last only up to two weeks, but Mr. Behnken and Mr. Hurley ended up with a longer and busier stay at the space station. Because of repeated delays by SpaceX and Boeing, NASA ended up short-handed, with only one astronaut, Christopher J. Cassidy, aboard the space station when the Crew Dragon and its two passengers docked.
They stayed two months, helping Mr. Cassidy with space station chores. Mr. Behnken and Mr. Cassidy performed four spacewalks to complete the installation of new batteries on the space station. Mr. Hurley helped by operating the station’s robotic arm.
Credit Source: https://www.nytimes.com/2020/08/02/science/spacex-nasa-return.html