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albumentoday at 1:16 AM2 repliesview on HN

No, the plasma forms a teardrop shape around small craft like Orion, completely cutting off radio comms. Larger craft like starship or the shuttle which have a roughly cylindrical shape (vs Orion’s circular cross section) aren’t fully enclosed by the plasma. The shuttle had a transmitter attached to its tail for later flights, which could send back telemetry during re-entry.


Replies

m4rtinktoday at 4:59 AM

Well, provided you had a 30 MW microwave transmitter on board, you could punch through the plasma just fine, it has been done:

https://en.wikipedia.org/wiki/Sprint_(missile)

"Sprint accelerated at 100 g, reaching a speed of Mach 10 (12,000 km/h; 7,600 mph) in 5 seconds. Such a high velocity at relatively low altitudes created skin temperatures up to 6,200 °F (3,400 °C), requiring an ablative shield to dissipate the heat. The high temperature caused a plasma to form around the missile, requiring extremely powerful radio signals to reach it for guidance. The missile glowed bright white as it flew."

llbbddtoday at 1:39 AM

Awesome, thank you! I wonder if some kind of very long-tethered deployed antenna could enable this for the capsule or if the ratio of long-enough-to-work vs thick-enough-to-not-burn-off-completely just doesn't work. Time to read about the shuttle.