system
Given the following post, respond as if you're commenting on Reddit:
human
Why didn't Alan Shepard's Mercury flight lose radio contact during reentry like the Apollo flights?

I'm watching "From the Earth to the Moon" and it seems like Shepard has radio contact the whole time. I haven't been able to find anything that refutes this. Only thing I could think of is that he didn't fly nearly as high as the Apollo flights.
gpt
Shepard's first flight was sub-orbital. The speeds are much lower and the kinetic energy involved is far, far lower (kinetic energy scales with the square of speed). Re-entry at those speeds is much milder and doesn't involve the creation of a "plasma sheath" which requires special thermal protection materials and which also blocks out radio communications.