The NASA Regolith Excavation Challenge featured four teams that used odd machines to attempt to win a $250,000 prize from NASA.  The teams were challenged to dig mock moon dirt, also called regolith, inside of a one-ton sandbox.  None of the teams could dig the required 330 pounds of regolith in 30 minutes, which means no one claimed the prize purse.

A machine built by Technology Ranch of Pismo Beach came the closest, collecting more than 143 pounds of regolith in 30 minutes.  The other teams in the competition were from Rolla, Missouri; Rancho Palos Verdes; and Berkley, Michigan.

Next year's prize purse for the competition will be worth an estimated $750,000.

NASA officials said shuttle Atlantis' hail-damaged external fuel tank has successfully been repaired to meet safety standards.  Engineers were worried the fuel tank would have to be fully replaced, further delaying the shuttle launch an additional month.  The shuttle today began a slow journey back to the launch pad with hopes of a launch in early June.

NASA still hopes to conduct four manned shuttle launches in 2007.  It is unknown if the U.S. space agency will be able to conduct the four manned launches after such a long delay with the Atlantis launch.

Researchers who are working to help astronauts adapt to life back on Earth are also helping insomniacs on Earth.  Research indicates that subjects who were exposed to two 45-minute exposures of bright light in the evening can help the people adjust to a Martian-style day -- which is 24 hours and 39 minutes long.  Humans, plants, animals and fungi all live on Earth with a circadian rhythm, which is a 24-hour cycle that deals with the physiological processes of living beings.

The additional length of day is able to interfere with reaction times, ability to learn, as well as memory and sleep patterns.   Researchers had 12 volunteers -- from 22 to 33 years old -- who slept an average of eight hours.  The circadian days showed in the group ranged from 23.47 hours to 24.48 hour days.

Activities such as using a computer or notebook after dark can interfere with a person's internal clock, which makes it more difficult to fall asleep.