The ISS consists of a large assembly of habitation, life support, observational, communication and experimental systems, as well as solar arrays capable of producing over 120kW of power. By adding a low-thrust propulsion system, could the station be adapted for orbital exploration of other planets, rather than simply being dumped in the Pacific at the end of its operational life, or would critical systems have deteriorated by that time?

At school the teacher said that before the Big Bang, the Universe was like a small tennis ball. But where WAS this ball?

We are constantly releasing materials such as gases and sattelites into space, surely it would eventually fill up with them. Even if it won't, if we increased the amount of materials we released into space to an amount that was at a faster rate than the rate that the universe is expanding, would it fill up?

I have recently heard that a boomerang will return to the thrower, even in space. I was under the assumption that a boomerang works because of it's unique aerodynamic properties, these would be useless in the vacuum of space so I don't think the boomerang can return to the thrower, am I right?

I remember there was a lot of debate about the information about the Earth and the human race carried by the Pioneer/Voyager spacecraft becoming an invitation to invade by hostile aliens.

We consider ourselves an advanced/space-faring civilization but if a similar spacecraft from another civilization was to pass say between the Earth and the Sun (a) would it be detected? and (b) Could we capture it? I imagine that stopping a Kombi van sized object travelling at + 10 km/s without damaging it would be difficult. Also, the time between detection and being able to mount a capture mission would probably be impossibly short.

If you were to take a huge long tube with both ends covered over and stick one end up into space and leave the other one here, before uncovering both ends, would there be a huge vacuum effect? Assuming the tube is strong enough not to be crushed!

When I was lighting my candle last night I was thinking about if the flame on your candle would react in the same manor if it where lit and how it would burn in zero gavity for example on the international space station?

Why can't one of our space telescopes, capable of seeing galaxies many light years away, be pointed at the site of the moon landings where one can assume there are some remnants from the visits.

Would this definitely prove to any sceptics that humans landed on the moon? It would be a nice way to celebrate the 40th anniversary of the first landing.

Liza Brooks, Shrivenham, Wiltshire, UK