a screenshot from starship ift3 with visible reentry plasma on the ship
ELI5 what entry plasma is, and why it’s a big deal? Please, and thanks!
As spacecraft reenter the atmosphere from orbital speeds, they’re going so fast that the atmosphere is compressed enough (and so gets hot enough) to free the electrons from the atoms in the air. This forms plasma. The special thing here is that we got live video during this portion of reentry; the free electrons in plasma heavily interfere with radio communications, so in previous missions there has been a full communications blackout at that time. Starship did not experience that blackout, which is unique. I’m not qualified to say exactly why, but the team was stressing that Starship is big enough that it “punches a hole through the atmosphere”. Another factor could be the 4(?) starlink terminals on the leeward side providing redundant communications signals.
I’m not qualified to say exactly why, but the team was stressing that Starship is big enough that it “punches a hole through the atmosphere”
I think Starship is just wider than most spacecraft which have reentered so far, and so the plasma doesn’t completely surround the vehicle. I think the Space Shuttle also had a small hole in the plasma near the tail, through which communications could be sent. Smaller gumdrop-shaped capsules (like Dragon and Soyuz) are completely enveloped in plasma, and thus experience blackout periods.
