In an important speech US president George Bush said he wants a space shuttle replacement ready for testing by 2008, as well as a moon base.

The space shuttle will go back into space as soon as possible, but will stop flying by 2010.

It will cost loads of money to carry out the new missions, which some say would be better spent on other things.

The moon base could be a starting point for later space missions, because it's much easier to leave the moon's atmosphere than the Earth's and missions will be cheaper.

The US is going to pay for it all by moving money around that Nasa already has, and will hopefully get permission to give them an extra $1bn over five years.

US space goals:

• Finish US work on the International Space Station by 2010
• Return the space shuttle to flight, but retire it by 2010
• Develop shuttle replacement by 2008 for manned exploration by 2014
• Send astronauts back to the Moon as early as 2015, no later than 2020
• Use human and robotic exploration of Moon to prepare for living base and missions to Mars