Space Crew is not great at communicating its controls, and there is no manual.* This is a quick & dirty rundown of what I have gathered from reading the Steam forum and from in-game experimentation.

Number keys 1-6: each selects an individual crew member.
(Goes up to 7 if you use that option.)

H: send the selected crew member to the medical bay.

W: zoom camera in.
S: zoom camera out.

Z: toggle camera between ship interior and exterior. NOTE: this replaces the SHIFT key from Bomber Crew.

SHIFT: hold to look at a CCTV view of the ship interior. Use A/D or L/R arrow keys to switch cameras. Note this mode appears strictly cosmetic - you can't use other controls here. But it does look cool.

Do nothing: if you leave your game idle, it will switch between all CCTV cameras within the ship as a kind of "screensaver". Cool! Touching any game control leaves this mode. (e.g. W or left click will leave this mode, but J or M won't.)

That's all I know for now. Did I miss something? Quite possible. Please comment below if you're aware of other controls and I will update the guide as appropriate. Thank you for reading.