Washington - The space shuttle Discovery was on its way to the International Space Station on Monday as ground crews monitored a piece of space junk that could prompt a change of course.

A piece of an old satellite could require the ISS to perform an avoidance manoeuvre, forcing Discovery to slightly change course in order to arrive at the ISS on Tuesday.

Washington - The launch of the space shuttle Discovery planned for later Wednesday was abruptly cancelled just hours ahead of blast off.

NASA called off the launch after it discovered a leak in a hydrogen vent line between the shuttle and its external fuel tank. The US space agency made the decision ahead of a planned 9:20 pm (0120 GMT Thursday) launch.

Washington  - The launch of the space shuttle Discovery planned for later Wednesday was abruptly cancelled just hours ahead of blast off.

NASA called off the launch after it discovered a leak in a hydrogen vent line between the shuttle and its external fuel tank. The US space agency made the decision ahead of a planned 9:20 pm (0120 GMT Thursday) launch.

Technicians had been filling the tank with fuel and would now have to completely drain it. A new launch time was set for 8:54 pm Thursday (0054 GMT Friday).

Washington  - The launch of the space shuttle Discovery planned for

Washington  - NASA technicians on Wednesday removed three fuel valves from the space shuttle Discovery that they feared could break off and damage the craft during launch.

The valves control the flow of hydrogen from the engines to the external fuel tank. NASA planned to replace the valves with models that had flown on fewer missions, after a piece broke off a similar valve on the space shuttle Endeavour in November. There was no damage, but the incident raised fears that shuttles could be damaged in the future.

Los Angeles  - A NASA satellite meant to help scientists get a clearer picture of how the Earth reacts to carbon dioxide failed to reach orbit after launching early Tuesday from an Air Force base in California, NASA said.

The 278-million-dollar Orbiting Carbon Observatory was meant to take about 8 million measurements every 16 days for the next two years to give researchers a clearer picture of how the carbon cycle affects climate and how net emissions vary by region.