Two astronauts will make a hastily-planned spacewalk to try to fix an ammonia leak in the International Space Station’s power system.

NASA scrubbed space shuttle Discovery’s first landing plan tonight because of rain at Kennedy Space Center and was considering ordering a New Mexico landing - something it has done only once before.

Nasa managers cleared Discovery to return home today, planning for a possible touchdown in New Mexico for only the second time in space shuttle history because of bad weather on both coasts.