Given that space is expanding at present and maybe contracting at some time in the future...

One of the possible solutions of Einstein's General Theory of Relativity is that the universe may have sufficient density (and insufficient velocity), so that it expands, slows, stops, reverses, and collapses inwards, to a "Big Crunch".

Observations last century suggest that the density of the universe is

*fairly* close to the value that would allow it to expand indefinitely - at least to the accuracy that astrophysicists believe they can measure.

More recent observations deduce the presence of Dark Energy, which seems to be accelerating the expansion of the universe. If this continues, the universe will not start contracting. It won't return to a Big Crunch, and may in fact suffer a

Big Rip...

is it possible (space) is elastic?

An

ideal elastic material follows Hooke's Law - if you stretch it to twice it's original length, the force required will double.

When you have masses in space, if you double their distance, the force between them will decrease by a factor of 4. This is defined by Newton's law of

universal gravitation (or Einstein's General Relativity, if you want to be more accurate on cosmic scales).

So the behavior of ideal elastic materials is quite different from the behavior of masses in spacetime.