Dr Jim Green has warned that two rovers from Nasa and the European Space Agency (ESA) could find evidence of life within months of arriving on Mars in March 2021.
Those samples will then be crushed up and examined for organic matter in a mobile laboratory.
Dr Green compared the potential discovery to when the astronomer Nicolaus Copernicus stated that the Earth revolves around the Sun in the 16th century.
“It will start a whole new line of thinking. I don’t think we’re prepared for the results,” he told The Sunday Telegraph. “I’ve been worried about that because I think we’re close to finding it and making some announcements.”
Nasa’s rover Mars 2020 will drill into rock formations on the planet before sending test-tubes of rock samples back to Earth – the first time material from Mars will have been brought onto this planet.
Dr Green added that the discovery of life on Mars will give scientists a new set of questions to explore.
“What happens next is a whole new set of scientific questions. Is that life like us? How are we related?” he said. “Can life move from planet-to-planet or do we have a spark and just the right environment and that spark generates life – like us or do not like us – based on the chemical environment that it is in?”
Recent research has shown that planets which were previously thought to be uninhabitable may have once had suitable conditions for life.
Earlier this year, scientists discovered that there may be a vast and active system of water running underneath the surface of Mars.
A study released this month also claimed that Venus may have been habitable for 2 to 3 billion years before its atmosphere became incredibly dense and hot about 700 million years ago.
Recent research suggests that civilisations could exist on other planets, according to Dr Green.
“There is no reason to think that there isn’t civilisations elsewhere, because we are finding exoplanets [planets outside the solar system] all over the place,” he said.
His comments came less than 24 hours before technology entrepreneur Elon Musk unveiled a SpaceX spacecraft designed to carry crew and cargo to Mars or other planets in the solar system before returning to Earth.
Mr Musk said the company’s Starship was essential for the viability of space travel by introducing a spacecraft that can be reused.
The ship is expected to take off for the first time in about two months and reach 65,000 feet before it lands back on Earth.
Join our new commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies