Leading scientists have paid tribute to Colin Pillinger, the "eccentric professor" who failed to land a British spacecraft on Mars but inspired a generation.
Prof Pillinger, the driving force behind the Beagle 2 mission, died aged 70 after suffering a brain haemorrhage while sitting in his garden.
A short statement from his family said he passed away "peacefully" at Addenbrooke's Hospital, Cambridge, and referred to "this devastating and unbelievable time".
Despite a long and distinguished career in planetary science, Prof Pillinger will always be remembered for Beagle 2 - a very British space mission largely funded by private money.
The tiny craft was supposed to land on Mars on Christmas Day 2003 and search for signs of life. But contact with the probe was lost soon after it separated from its European Space Agency (ESA) mothership Mars Express on December 19.
Imran Khan, chief executive of the British Science Association, said: "Colin Pillinger was a true ambassador for science. Not only did his work capture the public's imagination, he was incredibly warm and generous with his time, especially in inspiring younger generations of scientists to follow in his footsteps.
"I'm sure the thoughts of everyone who had the privilege of meeting him will be with his friends and family at this time."
The Beagle 2 mission was estimated to have cost £50 million, with £5 million contributed by the UK government and £9 million by the ESA.
After the mission's failure Prof Pillinger spoke of his frustration and determination to see his dream of landing British technology on Mars come true, even after being diagnosed with primary progressive multiple sclerosis.
Prof Pillinger gained a PhD in chemistry from Swansea University in 1968 before becoming a research fellow at Cambridge.
He began his career at the American space agency Nasa, analysing samples of moon rock on the Apollo programme.
In 1991, he was appointed professor in interplanetary science at the Open University. He was awarded the CBE in 2003.
Prof Pillinger is survived by his wife Judith and children Shusanah and Nicolas.