Solar riches survive probe crash

Precious information is extracted from the remains of the Genesis space capsule that crashed into a US desert in 2004..... BBC News

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Space shuttle flight pushed back to July

NASA will delay the next space shuttle launch until at least July to replace fuel sensors inside the external tank, officials announced Tuesday.

The space agency had hoped for a May liftoff for the shuttle Discovery. However, NASA officials said glitches in one of the tank's hydrogen fuel sensors, which monitor fuel levels during liftoff, prompted the decision to replace all four sensors and push back the date.

"We want to make sure we have a really good set of cutoff sensors, because, after all, that is a critical function and we want to be safe when we fly," NASA shuttle program manager Wayne Hale said after two days of meetings about the issue.

NASA officials have been cautious since the shuttle Columbia disintegrated upon re-entry in 2003, killing all seven crewmembers on board. The accident was caused by foam debris that fell off the fuel tank and punched a hole in the shuttle's wing.

Last summer, Discovery made the first shuttle flight since the accident. Though debris again fell off the tank, it didn't hit the shuttle, and the vehicle landed safely in August. That launch was delayed by the same type of fuel sensor issue.

This time, one of the sensors gave unexpected readings during an electrical test before the tank was shipped from its New Orleans factory to the Kennedy Space Center in Florida late last month. NASA engineers have been debating what to do ever since.

The sensors are precise fuel gauges that measure the amount of liquid hydrogen in the tank during the shuttle's climb to orbit. In the last critical seconds of the ascent, they ensure that fuel levels are sufficient to support normal engine cutoff.

A malfunction could cut off engines early and force the shuttle commander to make an emergency landing. Another possible consequence: The engines could continue running until all fuel is gone, potentially causing them to overheat and break up.