Cameron Mackie, of Ilam School, asks :-

How would you plan plan a manned mission to Mars?

Colin Keay, a space scientist at the University of Newcastle, Australia, responded.

Very slowly, I'm afraid. Because most of the people who control such ventures are going cold on the idea. The politicians are baulking at the truly enormous cost; scientists are slowly realising that instrumented robots are much much better than human explorers in conditions as hostile as Mars; and medics are having grave doubts that humans could reliably function throughout such a lengthy mission, mostly under weightlessness.

Because of the cost, it seems the best bet is to proceed by stages: first establish permanently manned space stations in Earth orbit, then in lunar orbit; second, when the problems there are understood and overcome, send the components of a similar station to orbit Mars and use it as a base for the third stage, which is a manned landing and establishment of an outpost on Mars.

This will take decades. In the meantime, more and more sophisticated robot probes will explore Mars very thoroughly before humans set foot there. Gradually it is being realised that human sense organs, marvellously adapted to Earth conditions, are very inferior to instruments tailored to unearthly environments. So robots will be the trail-blazers.

Lastly the medical problems for humans undertaking the 250-day trip (it takes that long using a minimum-energy Hohmann trajectory) must be solved. The major difficulty is weightlessness, leading to bone and muscle wastage. We need space stations and transfer vehicles capable of providing a fair amount of artificial gravity: these have yet to be developed.

Yes, there will be manned missions to Mars sometime. Hopefully within your lifetime. Personally, I'd rather see viable space colonies happen.