Asked by Gerald Bryant
The main asteroid belt lies between the orbits of Mars and Jupiter and consists of a huge number of rocky objects ranging in size from a grain of sand to 950km (590 miles) across for the belt’s only dwarf planet, Ceres.
While it is difficult to know exactly how many asteroids are present, the sheer number concerned the mission scientists on Pioneer 10, the first man-made object to traverse the belt in 1972. However, as images from flyby missions have shown us, the huge belt is not so densely populated with asteroids as to cause too many problems. There can be many kilometres of space between asteroids allowing plenty of room to manoeuvre and the chances of a craft colliding with an asteroid are less than one in a billion. As a result, a total of 12 spacecraft have successfully travelled across this region of space and, if you had a suitable spacecraft, it is very likely that you could, too.
Answered by Sophie Allan, National Space Centre