New spacecraft experience setbacks all the time. SpaceX Starship prototype violently disassembled several times. Boeing launched the CST-100 but ended up in the wrong orbit. China isn’t a stranger to setbacks either.
China tested a prototype spacecraft on May 5th, 2020 in efforts to prove the technology was ready. It’s good it was a test and not an actual mission since the spacecraft did not perform as expected. The news agency Xinhua reported the spacecraft launched from Hainan China, operated abnormally during its return.
Heat Shields Need to work or expect a terrible day.
Spacecraft experience tremendous heat during the last minutes of their mission. The heat shield protects the spacecraft from that heat. NASA looked at lots of materials and tested many before using for heat shields.
NASA’s Space Shuttle used a thermal soak heat shield approach. The Shuttle tiles act as an insulating material. The design absorbs and radiates the heat away from the spacecraft structure. A second common approach is an ablative heat shield like those used for Mercury, Gemini, Apollo, and Orion spacecraft. These ablative heat shields commonly have a layer of plastic resin which experiences intense heating while entering the atmosphere. The heat shield wears away, carrying the heat away through convection.
If damage to the heat shield results in compromised performance, disaster can strike like the loss of the Space Shuttle Columbia and all crew aboard. With Columbia, during takeoff, the heat shield tile damage occurred. While returning to Earth, super-heated gasses snuck in through the damaged tiles and resulted in the accident.
Newer heat shield design strives to increase reliability and safety. NASA developed the Phenolic Impregnated Carbon Ablator (PICA) heat shield. SpaceX continued to develop and adopted the technology for a segmented 3.6-meter PICA-X shield used on its Dragon spacecraft. SpaceX shared that PICA-A’s usefulness potentially extends for hundreds of times for Earth orbit reentry with only minor degradation each time. This performance allowed NASA’s Stardust comet sample return mission to survive reentry from its deep-space mission.
