Watch report below by Heather Edwards:
They are the brains that put probes into Space to orbit the sun and are building huge telescopes to find ancient stars.
They are, of course, the incredible scientists working at the Rutherford Appleton Laboratories outside Oxford. Their work may be sensitive but they have opened their doors to hundreds of local schoolchildren.
The idea - to mark International Space Week - is to get the next generation hooked on space and all its possibilities.