Denial

Keep going... I think you're asking yourself the right questions...
(I forgot to write a walkthrough and I'm not sure I can solve it myself now )

Yes, I made it
Yes, the egg is the solution!

(some spoilers below)

It was an Eureka moment when I noticed that I was teleported in a non-random way after the "suddenly you feel a lurch of acceleration" message. Then I just had to drop the egg in the right room and plan my 2 routes (back to the main engine & back to my escape pod). Btw, nice touch with the long/short ladder that thwarted my first escape attempt!

Smooth egg and rough egg both worked for teleportation but when i used the smooth egg I die of old age when I return to earth - I guess it is radioactive or something?

It doesn't seem to matter if I pull the final switch in the control room (present) or chaos room (past). And the priceless rock doesn't get me robbed when I make my final escape after destroying the comet. I guess that only happens when you make premature escape attempts.

Very creative puzzles, but very tricky. I concur with hasseapa: I would probably not have made it past the first locked door if I had played it as a kid.

Thanks for a very well-written and well-crafted adventure, Kweepa!