IT WILL be hard to build a moon base when just getting off Earth burns up so much fuel – even with a tiny payload. An orbiting fuel depot could solve the problem.
The idea is not new, but a snag has always been that sunlight falling on the fuel tanks would make them hot enough to vaporise the liquid hydrogen and liquid oxygen needed to propel many spacecraft. So Bernard Kutter of the United Launch Alliance in Boulder, Colorado, and colleagues have designed a tank with a sunshade made of and aluminium attached to it. This would unfurl…
