Watch: Prince William's criticism of billionaire space race addressed by astronaut Tim Peake - 'It's incredibly important'
Astronaut Tim Peake has disputed Prince William's criticism of the space race, saying space is "incredibly important to us" as it provides climate change data and supports the national infrastructure.
Speaking after Star Trek actor William Shatner became the oldest person to reach space, the Duke of Cambridge said the space race detracts focus from addressing climate change on Earth.
The royal told the BBC: "We need some of the world's greatest brains and minds fixed on trying to repair this planet, not trying to find the next place to go and live."
Commenting on Mr Shatner's journey to space, Mr Peake said: "It's the most incredible thing to leave your home planet behind and to go and look at the Earth from space and look back on this beautiful planet we live on."
But the astronaut, who served on the International Space Station for six months between December 2015 and June 2016, disagreed with the prince's remarks.
"Space is incredibly important to us right now," he told Sky News's Kay Burley.
"More than 50% of all our climate change data comes from space-based assets. It's part of our critical national infrastructure. Everybody is using space on a daily basis, probably without even knowing it. But we need to use space sustainably. We need to consider the environment."
He added: "When you look at rocket fuel, some of the best rocket fuel is liquid hydrogen and liquid oxygen, and the byproduct is water. And actually space has a very tiny impact on the environment but that doesn't mean that we can't be better at it."
Watch: Prince William takes swipe at billionaire rocket men
Mr Peake said he was working with companies to develop environmentally-friendly rocket fuel.
He also gave the example of SpaceX's efforts to look at the sustainability and reusability of rockets and plans to clear up space to "protect it as an environment for future generations".
He added: "People are doing as much as they can.
"This obviously needs everybody to collaborate and work together and it needs everybody to be responsible. There's no point in just one small part of the industry or one small nation doing this.
"This needs to be a global effort to make sure that we protect space, we use it responsibly, and we clean up the mess that's already there."