Astronauts Doug Hurley and Bob Behnken are dropped from the International Space Station on Saturday in their Crew Dragon “Endeavor” capsule, en route for a parachute-assisted spray Sunday in the Gulf of Mexico to conclude a 64-day trial flight human commercial SpaceX spacecraft.
With favorable wind and sea conditions expected in the Gulf of Mexico on Sunday, mission control gave the green light to Hurley and Behnken to board their Crew Dragon spacecraft and close the doors between the capsule and the space station. .
After a series of leak checks, a release command at 19:30 EDT (2330 GMT) began a series of automatic passes on Saturday to leave the station. The power umbilicals broke away inside the latch mechanism, then 12 hooks opened before the Dragon Endeavor spacecraft fired the thrusters with a couple of short pulses to rise from the research complex at 1
SpaceX’s Dragon Endeavor disengaged from the International Space Station, starting the journey on Earth with astronauts Doug Hurley and Bob Behnken.
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Wearing pressure suits made to measure for SpaceX, Hurley and Behnken monitored departure on touchscreen displays inside their Dragon Endeavor spacecraft. NASA astronaut Chris Cassidy, commander of the station’s Expedition 63 crew, rang the “ship’s bell” on the research complex and ceremoniously announced the release of the Dragon.
Cassidy and her two Russian crewmates – Anatoly Ivanishin and Ivan Vagner – will remain on board the space station until October, when they return to a landing in Kazakhstan on a Russian Soyuz spacecraft. Three new crew members will launch to the space station on October 14 on a new Soyuz spaceship.
During their two-month stay, Hurley and Behnken assisted Cassidy, Ivanishin and Vagner in the duties of the space station, carrying out experiments and maintenance. Behnken joined Cassidy on four spacewalks in June and July to replace the batteries in the space station’s solar power modules.
“Chris, we can’t really thank you enough,” Hurley said in a radio exchange with Cassidy shortly after going off-hook. “It has been an honor and a privilege to be part of Expedition 63 with you, Anatoly and Ivan. It has been a fantastic two months and we appreciate everything you did as a crew to help us try Dragon on his maiden flight.”
Hurley also thanked NASA’s mission controllers at the Johnson Space Center in Houston and the SpaceX teams in Hawthorne, California for their support.
“We can’t wait to splash tomorrow,” said Hurley. “Also, I would like to wish you great success for the rest of the expedition and a safe return flight in the fall. Take care of yourself friend. “
“Bob and Doug, I sincerely agree with those feelings,” replied Cassidy. “It was a real pleasure. It was an honor to serve you. Safe travel and successful landing. Endeavor is a great ship. Godspeed”.
A series of rockets maneuvered the crew capsule at a safe distance from the space station and the astronauts planned to begin an eight-hour sleep period at 11.40 pm. EDT (0340 GMT).
Hurley and Behnken will close their 64-day test flight – designated Demo-2, or DM-2 – on Sunday with a braking burn to get out of orbit and enter the atmosphere, hitting a crash in the Gulf of Mexico near Pensacola , Florida.
“Our mission is not over,” said Hurley on Saturday before dropping off. “The DM-2 test flight is, in some ways, only two thirds complete. We made the ascent, the appointment and the docking. We have completed our anchored objectives and it is now the entry, descent and descent phase. “
“The hard part was getting us thrown, but the most important part is getting us home,” said Behnken.
Astronauts are expected to wake up at 7:40 am EDT (1140 GMT) on Sunday to begin preparations for their return to Earth.
Hurley and Behnken will pack their bags and prepare the spaceship cabin for entry. They will also drink liquids in a process known as “fluid loading” aimed at facilitating their adaptation to Earth’s gravity after two months in orbit.
Assuming that a final assessment of weather and sea conditions appears favorable in the recovery area near Pensacola, the Dragon Endeavor spacecraft – flying on autopilot – will eliminate the section of its non-pressurized trunk at 13:51. EDT (1751 GMT). The trunk is attached to the rear of the Dragon’s crew module and contains the ship’s solar panels and energy-generating radiators used to disperse the interior heat of the spacecraft into space.
The trunk will remain in a relatively low orbit and will naturally fall back into the atmosphere and burn.
Meanwhile, the Dragon crew module will move in the correct orientation for a deorbit burn using the spacecraft’s Draco thrusters. The braking maneuver will begin at 13:56 EDT (1756 GMT) and last for more than 11 minutes, slowing down the ship’s speed by nearly 168 mph, or 75 meters per second.
That change in speed will allow Earth’s gravity to bring the spacecraft back into the atmosphere, which will do most of the rest of the work to slow down the dragon’s speed for splashing.
The spacecraft will close the front anterior cone at 14:11 EDT (1811 GMT) before plunging into the recognizable atmosphere at 14:36 EDT (1836 GMT), moving at around 17,500 miles per hour (28,000 kilometers per hour).
Hurley and Behnken will wear their SpaceX flame resistant pressure suits at the entrance, the same clothes they wore during their launch on May 30 from the Kennedy Space Center in Florida atop a SpaceX Falcon 9 rocket.
Flying with its blunt end facing the heavier weight of the airflow, the spacecraft’s heat shield will encounter temperatures of up to 3,500 degrees Fahrenheit (1,900 degrees Celsius) as it dives into the atmosphere.
The accumulation of overheated around the capsule should interrupt communications with the crew for about six minutes during entry. Engineers expect to restore communications with astronauts once Dragon Endeavor exits the hottest part of the entrance around 14:42 EDT (1842 GMT).
The Drogue parachutes will be released from the top of the capsule at 14:44 EDT (1844 GMT), followed by the deployment of four main orange and white parachutes approximately one minute later.
The drug chutes will deploy when Dragon Endeavor is descending approximately 18,000 feet, or 5,500 meters, when the capsule is moving at around 350 mph, or more than 550 kilometers per hour. The four main slides come out at an altitude of around 6,000 feet, or 1,800 meters, and at speeds of around 119 mph, or 191 kilometers per hour.
Parachutes will slow the capsule’s speed due to a slight drop at 14:48 EDT (1848 GMT) in the Gulf of Mexico, hitting a position south of the Alabama-Florida border.
Entering Sunday’s entry and splashdown, mission control identified a backup recovery site in the Gulf of Mexico near Panama City, Florida. SpaceX and NASA have a total of seven Crew Dragon abatement sites – four in the Gulf and three in the Atlantic – but tropical storm Isaias is expected to move near mission recovery areas off the east coast of Florida on Sunday.
If weather conditions deteriorate in the Gulf of Mexico, control of the mission could thwart Sunday’s return opportunities. NASA officials said astronauts have food, water and other supplies for at least three days on the Crew Dragon after being dropped from the space station on Saturday night.
A SpaceX recovery ship called “Go Navigator” will be on the station in the Gulf of Mexico to retrieve the spaceship Crew Dragon after it crashed.
Two “fast boats” will line up from Go Navigator and approach the capsule, which measures approximately 13 feet (4 meters) in diameter and 16 feet (5 meters). After verifying that the spacecraft is secure, the larger recovery vessel will position itself next to the dragon and lift the capsule out of the water using a lifting frame.
Once the dragon is on the Go Navigator bridge, Hurley and Behnken will disembark the capsule and undergo medical checks.
Benji Reed, SpaceX’s crew director of mission management, said the recovery ship will have around 44 people on board, including SpaceX and NASA officials, doctors, nurses, and other medical personnel. Spacecraft technicians will also be on board to recover and protect the dragon capsule.
After an initial health assessment, Hurley and Behnken will board a helicopter to reach Pensacola Naval Station, where they will board a NASA plane for the return flight to their home base in Houston.
Astronauts are returning to Earth with approximately 150 kg of cargo, including specimens of frozen experiments, personal equipment and a U.S. flag left on the space station by the space shuttle crew in 2011.
Hurley was the pilot of the last space shuttle flight.
The flag also flew on STS-1, the first shuttle mission, in 1981. The last crew of the shuttle left it on the space station to be returned by subsequent astronauts to fly to the research laboratory on a US spacecraft.
In the end, SpaceX won the “catch the flag” contest on the high frontier.
NASA awarded billions of dollars in contracts for the development and piloting of new commercial crew capsules built in the United States on SpaceX and Boeing in 2014, after several years of preliminary design work.
SpaceX launched a successful unmanned Crew Dragon demonstration flight to the space station in March 2019, then broke a halt during ground tests of the Crew Dragon’s dropout system last year. After redesigning part of the interruption system and checking new changes to the capsule’s parachutes, SpaceX launched the first Crew Dragon mission with astronauts on May 30th.
Boeing’s CST-100 Starliner crew capsule was launched into orbit for its first unscheduled test flight last December, but encountered software problems that prevented the spacecraft from reaching the space station. Boeing recovered the spacecraft with a successful landing in New Mexico, but officials plan to fly the unmanned demonstration mission again later this year before authorizing the Starliner to transport astronauts for the first time in 2021.
With the Crew Dragon on the verge of completing its first round-trip space mission with astronauts, SpaceX and NASA will analyze the data of the Demo-2 test flight before formally certifying the commercial capsule for the operational rotational launches of the crew.
The first crew rotation flight, called Crew-1, is slated to launch this fall on a Kennedy Space Center SpaceX Falcon 9 rocket. Four astronauts are assigned to flight Crew-1 and last week NASA announced the crew’s duties for the Crew-2 mission in spring 2021, Crew Dragon’s second operational mission to the space station.
Subsequent Dragon Crew missions to the space station will also be launched with up to four passengers and the spacecraft – once certified after the return of Demo-2 – will be able to perform missions of a maximum duration of 210 days.
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