the Lost in Space episode Visit to a Hostile Planet,
the Robinson family find themselves back on Earth, but 50
years ahead of their proper time of the 1990s. They decide
to return to where they were before in space and time, because
if they remain in the 1940s they will not fit in - they would
be treated as outcasts or lunatics, or their 1990s science
might alter history.
the Jupiter 2 contains freezing tubes for long space
flights. Why can't they just freeze themselves and set the
controls to wake them up 50 years later?
the sort of idea that only an ardent reader/watcher/listener
of time-travel stories (such as you and I) would think of!
Maybe it just didn't occur to the Robinsons to do that.
Alternatively, the notion might have been considered but quickly
ruled out if it was deemed unsafe to use the suspended-animation
tubes for such a long period of time.
There's also the problem of the Jupiter 2 being discovered
while its crew are dormant. Where would they hide the ship?
Anywhere on Earth and it might be found. In space there would
be the problem of fuel running out, an orbit decaying or collision
with asteroids or comets (which, in the Lost in Space
universe, are hot rather than icy!). Even if they were to
set down on one of the other planets or moons in the solar
system, there would still be the risk of discovery by space
probe or of a loss of atmospheric integrity.
Personally, I've always been more mystified as to how they
manage to get back to their own time. I guess we must assume
that, as in Star Trek, re-creating the original conditions
of the time warp (in this case, extreme velocity) allows them
to travel back in the opposite direction. Or maybe they had
created an actual rip in the fabric of space-time, which it
was possible to travel back through.
Other than that, of course, the science of Lost in Space
makes perfect sense... not!