Barack Obama promises to help send people to Mars within 20 years

Barack Obama has vowed to help send people to Mars within the next two decades, saying he will work with private firms to achieve the goal.

The US President also says he is getting scientists, engineers and students together this week "to dream up ways to build on our progress and find the next frontiers".

Not all experts think his goal is achievable by the 2030s.

Dr Scott Pace, from George Washington University, is one of them.

He said: "It's possible to imagine putting astronauts in orbit around Mars, it's possible to imagine visiting Martian moons by that time.

"But the technical challenges and the budgetary challenges I think are pretty daunting."