Engineers performed last-minute repairs to an electrical glitch with NASA鈥檚 Aqua satellite on Friday enabling the spacecraft to launch only two days behind schedule on 4 May.
The satellite鈥檚 key task will be to monitor the Earth鈥檚 water systems. Its creators say it could improve weather predictions and aid global climate studies.
The launch was placed in doubt when final checks by engineers revealed a problem with the electrical cables that would connect the spacecraft to its Boeing Delta launch rocket.
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The connections have now been repaired and a NASA spokeswoman says: 鈥淲e鈥檙e very confident that everything is safe for launch.鈥� The satellite is set to take off from the Vandenberg Air Force Base in California.
Water watch
Once in orbit, Aqua will focus in on the planet using six onboard instruments. Some will study infrared and visible parts of the light spectrum to determine cloud properties, sea surface temperatures and ocean colour. Others will use microwaves to determine atmospheric temperature and humidity.
鈥淎qua will provide unprecedented information on the global water cycle,鈥� says Ghassem Asrar, Associate Administrator for NASA鈥檚 Earth Science Enterprise.
NASA built four of Aqua鈥檚 six instruments while Japan鈥檚 National Space Development Agency and the National Institute for Space Research in Brazil constructed the other two.
Aqua will perform a similar job to Envisat, another Earth-monitoring satellite launched by the European Space Agency on 1 March. This satellite has already begun returning environmental data to scientists.
Aqua comprises one part of a NASA鈥檚 Earth Observing System (EOS), a three-satellite mission to closely monitor Earth鈥檚 land, sea and atmosphere. The first of these spacecraft named Terra was launched in December 1999 and has focused on the planet鈥檚 surface. A satellite named Aura is set to study Earth鈥檚 atmosphere from orbit in January 2004.