The Crew Dragon spacecraft, produced by private company SpaceX, is scheduled to return from the International Space Station (ISS) and fly into the Atlantic Ocean on August 2. astronauts Robert Behnken and Douglas Hurley will begin the auction procedure on Aug. 1, and re-enter Earth’s atmosphere the next day – a total of 64 days from the lift off.
The historic launch took place on May 30 from NASA’s Kennedy Space Center in Florida, which marked the first time a commercial space company has brought humans into orbit around the Earth. But while the launch was a nail-wielding experience to watch, re-entry will be even more risky ̵1; presenting a tense moment for mission control. SpaceX founder Elon Musk said reentry is indeed his “biggest concern.”
The joint SpaceX and NASA mission was successful in coupling with the ISS, enabling astronauts to complete scientific and maintenance work, including four spacecraft.
Importantly, the primary purpose of the mission is to test and demonstrate the ability of the vehicle to carry a crew safely to and from Earth orbit, as a first step in the initial plan of regular ISS missions and commercial spaceflight.
Danger points again
The extreme speeds and temperatures the vehicle has to endure present a major challenge for engineers and make it again the most dangerous part of a mission.
The hazard begins with finding the right angle of trajectory as the spacecraft enters the upper atmosphere. If it is too stationary, astronauts will experience potentially deadly g forces, and the friction of the air suction can cause the spacecraft to explode. If it is too low, the capsule will instead catastrophically miss the atmosphere and re-enter Earth’s orbit.
The spacecraft enters the upper atmosphere at 27,000km / hour. That is 7.5km / second, or more than 20 times the speed of sound. In each unit you prefer – this is fast. At these speeds, a very strong shock wave forms around the front of the vehicle, compressing and overheating the air. Managing immense thermal load is a huge re-engineering challenge.
At the most extreme stage, the temperature of the air in the shock layer exceeds 7,000 ° C. By comparison, the temperature at the surface of the Sun is about 5,500 ° C. the heat shield of the vehicle so hot that it starts to glow – a process called incandescence. SpaceX’s new and advanced PICA-X material heat shield has managed to protect the capsule in test flights, after which it is recovered in a highly burned state.
The air molecules around the vehicle also break down into positively charged atoms and free electrons – the so-called plasma. When some of the molecules recombine, the extra energy is released as photons (light particles) – which gives the air around the vehicle an amber glow.
This plasma layer can be beautiful, but it can cause a radio outage. When an electron travels along a conductive wire, we are getting electricity. Similarly, when free electrons move through the plasma around the vehicle, we get an electric field. If the electric field becomes too strong, it may reflect and reduce the radioservices trying to reach the spacecraft.
Stopping not only leads to loss of connection to onboard crew and flight data, but can also make remote control and guidance impossible. The Apollo missions, the Mars Pathfinder and the recent, failed 2018 Soyuz rocket, launch the cessation of all communications made in the order of the minutes. NASA mission control is anticipating a nerve-wracking six-minute blackout during the peak heating phase of Crew Dragon’s return – if anything goes wrong at this time, it’s in hands the astronauts.
Another risky stage is parachute-assisted landing. The Dragon Crew will send four parachutes in the final stage of reentry, as the vehicle lands toward a light spill in the Atlantic Ocean off the Florida coast. This maneuver has been tested by SpaceX 27 times before next week’s crew landing, so it should work.
Successful landings will have major implications – reducing the costs of space exploration through the use of reusable rockets that allow private space exploration. While SpaceX engineered the Dragon crew vehicle under contract with NASA, the company is free to use the spacecraft for commercial flights without NASA’s involvement after operational certification.
SpaceX has a partnership with commercial aerospace company Axiom Space, which has the ultimate goal of building the world’s first commercial space station. The proposed commercial activities for the station are broad: from space research and manufacturing to support space exploration.
Then there is space tourism. Private citizens are already queuing for their ticket to space, and with a successful Dragon Crew splashdown, they won’t be waiting long. An American space tourism company, Space Adventures (partners with SpaceX), is planning to offer zero-gravity atmospheric flights, orbital flights with a choice of space and Moon orbit until late 2021.
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Whether space tourism is debatable is whether the costs, environmental impact and hazards of space flow are justified. As this article shows, providing the necessary security information for Space Adventure ticket holders will be far more comprehensive than your ordinary “Please take a moment to read the security card at seat pocket in front of you “.