On May 30, SpaceX and NASA made history when a Crew Dragon spacecraft carrying two astronauts (Robert Behnken and Douglas Hurley) launched onto a Falcon 9 rocket and met with the International Space Station (ISS). With this single flight, NASA and SpaceX demonstrated that the United States once again has the ability to launch nationally, something they have not enjoyed since the space shuttle retired in 2011.
In a week, on Sunday, August 2, Robert and Douglas will return to Earth using the same Crew Dragon spacecraft (called Effort) that brought them to the ISS. This is the most crucial part of the Demo-2 flight, where the spacecraft is tasked with bringing astronauts home, safe and sound. As you can imagine, there are plenty of people who are understandably nervous, including SpaceX founder Elon Musk.
This is certainly understandable considering what the Effort and his astronauts will pass to get home. After leaving the station on August 1, Robert and Douglas will re-enter the Earth’s atmosphere by traveling, reaching speeds of up to 25 times the speed of sound (30,870 km / h; 19,180 mph). This will create incredible air friction and cause temperatures outside the spacecraft to reach 1925 ° C (3,500 ° F).
Once Robert and Douglas have addressed the Effort and everything is ready for departure, the spacecraft will separate from the ISS airlock and fire its engines briefly to put some distance between it and the station. Once you are far enough away, it will start your engines again for a longer period to put you on the correct flight path to re-enter Earth’s atmosphere.
the Effort It will then dump its bottom section (also known as the trunk) where your fuel tanks, solar panels, and other hardware are kept. This will expose the capsule’s heat shield just before the spacecraft begins to fall into our atmosphere. As Musk indicated in an interview with Irene Klotz from Aviation Week in May (just before the launch of Demo-2), he fears this stage more, and not just for the obvious reasons.
As he indicated, many of his concerns have to do with the design of the Crew Dragon itself:
“The part I would be most concerned about would be reentry, which hopefully won’t happen in a few months. With Dragon 1, we have a simple taper on the leeward side, essentially the rear shell, of the spacecraft, making it really quite symmetrical, with no particular bumps or anything.
Whereas with Crew Dragon, because we have the side-mounted exhaust thrusters in the rear shell that creates an asymmetry. If it spins too much, it could trap the plasma in the Super Draco exhaust propeller pods and could cause control disturbances or overheat things.
Of course, Musk also emphasized in that interview that his company and its many engineers have thoroughly tested the design of the Crew Dragon. The design was also tested at launch prior to its manned flight, with an unmanned orbital flight (Demo-1) conducted on March 2, 2019, which managed to successfully meet and dock with the ISS and return to the Land of safe way.
This was followed by an explosion during a static fire test on April 20, 2019 (apparently due to a nitrogen tetroxide leak), which destroyed the Demo-1 spacecraft. However, SpaceX did it again on January 19, 2020, where another Crew Dragon spacecraft nailed the test of its in-flight abort system. Therefore, it is not that SpaceX, under the watchful eye of NASA, has not done its due diligence.
“We have looked at these six ways as of Sunday, so it’s not like I think this is going to fail,” Musk said. “It’s just that I’m a little concerned that it’s asymmetric in the back shell and that you might have a weird guy or roller coupling when you go in if you turn too much. I think this is low risk, but that’s what I would put as my biggest concern. “
NASA Administrator Jim Bridestine and the NASA Commercial Crew Program (PCC) took to Twitter to announce that August 1 would be the mission start date. In general, the mission will take between 6 and 30 hours, depending on when NASA decides to start the process. As Bridenstine indicated, it all depends on weather conditions.
After passing through Earth’s upper atmosphere, the Effort It will deploy its parachutes to slow the ship down as it reaches the lowest and densest parts of the atmosphere. The first conduit will be deployed at about 5,500 m (18,000 ft) and the Endeavor’s the rockets will fire, slowing down the capsule until it reaches a speed of 190 km / h (119 mph) at an altitude of 1830 m (6,000 ft).
At this point, more parachutes will be deployed and the The capsule will land 25 to 200 miles (40 to 320 km) off the Florida coast. If all goes as planned, astronauts Bob and Dough will return to Cape Canaveral as the first American astronauts to launch from American soil in nearly a decade.
The next step will take place at the end of September at the earliest, where NASA and SpaceX will conduct the Crew Dragon spacecraft’s first operational mission and its second manned flight. Known as Crew-1, this mission will further dominate the national launch capability and will consist of the four Expedition 64 crew members who will be transported to the ISS.
Further reading: Business Insider, POT
