Scientists have made a discovery that could lead to a revolutionary drug that actually reverses ageing.
The drug could help damaged DNA to miraculously repair and even protect Nasa astronauts on Mars by protecting them from solar radiation.
A team of researchers developed the drug after discovering a key signalling process in DNA repair and cell ageing.
During trials on mice, the team found that the drug directly repaired DNA damage caused by radiation exposure or old age.
'The cells of the old mice were indistinguishable from the young mice after just one week of treatment,' said lead author Professor David Sinclair.
Human trials of the pill will begin within six months.
'This is the closest we are to a safe and effective anti-ageing drug that's perhaps only three to five years away from being on the market if the trials go well,' said Professor Sinclair.
The work has drawn the attention of Nasa, which is considering the challenge of keeping its astronauts healthy during a four-year mission to Mars.
Even on short missions, astronauts experience accelerated ageing from cosmic radiation, suffering from muscle weakness, memory loss and other symptoms when they return.
On a trip to Mars, the situation would be far worse: Five per cent of the astronauts' cells would die and their chances of cancer would approach 100 per cent.