No space mission can succeed without communication, so our second set of Rough Science space challenges are all based around making contact. Jonathan and Kathy have to come up with a way of communicating that doesn't use sound waves - because in the vacuum of space, there's nothing for them to move through.

It took two years and a million pounds to develop a pen for use in space - one that would work in zero gravity. Ellen and Mike have no money and just three days to come up with their own version.

Iain's challenge is very different. He has to find a way to communicate with aliens! NASA faced this problem when they sent the Pioneer probe out into deep space. Their solution was a plaque with crucial information about the creatures (us) who had sent the craft out into space. So Iain has to come up with a plaque that would communicate information about the Rough Science team to aliens.

Kathy and Jonathan come up with a truly extraordinary Rough Science way of communicating without sound waves. They find a way to carry a voice on a sunbeam! Their technique involves getting a voice to "wiggle" a light beam, then reflecting the wiggling light beam to a receiver which turns the light beam back into sound.

Down on Earth, pens rely on gravity to deliver ink to the nib. But in space there's no gravity, so Mike and Ellen need some other force to push ink to the nib. Although we can't take them into space to test their pen, there is another way to find out if they've succeeded; if their pen can write upside down then it will prove it isn't using gravity to make the ink flow. Mike comes up with two designs; a pen that uses capillary action, and a ballpoint pen with a balloon inside it to put pressure on the ink. And Ellen goes hunting amongst the plant - and animal! - communities in her quest to make a workable ink.

Iain's plaque to communicate with aliens is inspired by the local geology - he decides to make it out of plaster of Paris because there should be gypsum in the hills around the mine, and gypsum is the raw material for plaster of Paris. The trouble is, his geology lets him down; what he thinks is gypsum turns out to be something else. He has to rely on some clever chemistry to get his challenge back on track. But he eventually comes up with an ingenious design for his plaque.