大象传媒

It's been 30 years since the last moon missions, when scientists last got their hands on solid samples from space - until now. In this episode of Frontiers Peter Evans looks at the extraordinary new space missions that have collected particles from the sun, and from a comet at the far reaches of our solar system.

The last time actual solid samples were brought back to Earth was from the Moon with the 1972 Apollo mission and the Russian expedition shortly afterwards. But NASA has now managed to retrieve samples from the sun with a mission called Genesis and from a comet at the far reaches of the solar system with the Stardust mission. In general terms, we know quite a bit about the evolution of our sun and planets.

But, with the Stardust mission to the comet Wild 2, scientists hope that many of the fine details will be filled in, as well as providing information about other stars and their planets. The sample-return capsule landed in Utah in January this year, it allowed NASA's scientists to handle the material that streams out of comets for the first time in human history.

The Genesis set off in 2001 to grab solar wind particles and crashed back to earth three years later, providing invaluable samples which were collected on an array of hexagonal panels. These particles could tell scientists how the sun and the planets grew out of a cloud of dust and gas billions of years ago.

Already both the Stardust and Genesis missions are recognised as a resounding success - technically and scientifically, and the fact that the scientists have only just begun working on the samples they have collected should mean that there will many more revelations about the history of our solar system to come from them.