The United States is expected to put two scientific satellites into orbit around the moon in October 1996, University of Utah physicist Richard W. Shorthill said Friday.
The Lunar Observer project is a preliminary step toward a manned mission to Mars in the next century, possibly as soon as 2005.Shorthill arrived in Utah Friday evening after spending several days at a NASA-sponsored space exploration conference in Pasadena, Calif., where scientists were invited to contribute ideas about the planned Lunar Observer mission and conduct research aimed at making the 1996 unmanned expedition a success.
Shorthill said it has not been decided whether to push the satellites toward the moon with an Atlas or a Titan rocket. "The Titan will cost $100 million more than the Atlas, but it will push much more weight - 1,194 kilograms more.
"The project is expected to cost between $500 million and $700 million and has been approved by the Bureau of the Budget, but it is not a line item yet and hasn't been named, so scientists are waiting for that final line item approval that will mean the project is certain."
Shorthill, former director of the Geospace Laboratories at the U. Research Institute and now a research associate professor in mechanical engineering in the university's College of Engineering, said the mission now calls for a large satellite - perhaps 6 feet long and weighing 2,600 pounds - to arrive at the moon in four days.
"It will then take 25 days to get into its projected orbit around the moon. Soon after arriving near the moon, the main satellite will put a smaller satellite into orbit. The main Lunar Observer will travel around the moon in a polar orbit at about 70 kilometers above the moon's surface.
"It may get as close as 50 kilometers on occasion. The smaller satellite will travel around the moon in a polar orbit at a height of about 200 kilometers.
"The smaller satellite will map the moon's gravity field. The larger satellite will contain a variety of instruments to measure X-rays, gamma rays, visible and near-infrared radiation and thermal emissions (far-infrared)."
He said the satellite also will take black and white pictures and have a laser altimeter to measure the moon's topography.
"The larger satellite will map all of the moon's surface over a period of one year and then conduct further mapping the second year. There is a possibility the satellite will be able to take measurements for three years.
"The subsatellite will probably crash into the moon after three years, but the larger satellite will continue to orbit the moon for many years."
Shorthill said the satellite mission will not only map the surface of the moon but will be able to measure the structure of the moon beneath its surface and to its core.
"The satellites will send whatever information they get back to earth by radio signals, so scientists will be able, in effect, to see what the satellites are seeing.
"The Soviets are interested in working on the U.S. subsatellite and there is a possibility they will get involved in the Lunar Observer mission, but for the most part this is an American venture."
He said the Japanese are sending a satellite into space in March that will dispatch a football-size satellite around the moon. It will measure the moon's electrical fields and particles, which may be electrons or molecular material, and will orbit for a year at about 100 kilometers from the moon's surface.
Shorthill said he will travel to a Lunar and Planetary Science Conference at the Johnson Spacecraft Center, Houston, Texas, March 12-16, where further discussions of lunar missions and the manned Mars mission will be held.