Rebbeca Bangma, of Woodend School, asks :-

We have been talking about Concorde and would like to know if a plane can keep flying upwards into space?

Jim Rankin, a physicist who is a pilot and flying instructor in the Royal New Zealand Air Force at Ohakea, responded.

Unfortunately, no, for two reasons.

`Space' is exactly that - space - with virtually nothing there. In particular, there is no atmosphere. Normal aircraft can only fly because their wings produce a force called LIFT when air flows past them. The higher you go above the ground, the air becomes thinner, or less dense. Eventually, a climbing aircraft reaches a height beyond which there is sufficient air to produce the required lift, and it can't climb any more.

Rockets don't need wings to get lift, so they can climb into space.

As the air gets thinner, there is also less oxygen available to breathe. High altitude mountaineers and pilots carry oxygen to help them breathe in the thin air. Big passenger aircraft `pressurise' instead, so that while the aircraft might be flying 12 km high the air inside is the same as at 2.5 km and you can breathe normally.

Similary, jet engines need oxygen, which is burnt with fuel to produce thrust. Eventually the engines of a climbing aircraft would stop through lack of oxygen - just like a fire that goes out when it is covered up and can't get any fresh air. Rockets get around that problem by carrying their own oxygen with them. The Space Shuttle carries an enormous tank on lift-off which is mostly full of liquid oxygen to power the rocket engines.

So, normal aircraft can't get into space. Some special aircraft use wings to get as high as possible, then rockets after that. The X-15 rocket plane climbed to over 105 km this way. Hopefully, in your lifetime, passenger-carrying rocket planes, with new engines that can be jets at low altitudes and rockets higher up, will mean that aircraft will fly into space.