CAPE CANAVERAL, Fla. (AP) - A satellite trailing the space shuttle Discovery has gathered evidence that supports the controversial theory that snowballs the size of a house are bombarding Earth's atmosphere.
Robert Conway, a planetary physicist at the Naval Research Laboratory, said Monday that preliminary findings from his ultraviolet telescope on the satellite indicate lots of hydroxyl in the atmosphere at the high northern latitudes. That means lots of water vapor.
Conway said one possible explanation for all this water vapor at altitudes of 43 miles to 56 miles is large space snowballs, a theory presented by a University of Iowa physicist in May.
Another possibility is that it's coming from meteorites, Conway said.
"This is where all the junk that we sweep through as the Earth goes around the sun, this is where it has to come through, and maybe some of that junk is snowy comets," he said. "But there are other things, and I think we need to look at all of them."
When Conway's telescope flew in space in November 1994, it detected almost no hydroxyl above 43 miles, he said. This time, it's checking the far north: Alaska, northern Canada, northern Russia, Greenland and Sweden.
The satellite, which also is gathering data on Earth's ozone layer, has been flying free of Discovery since Thursday. The astronauts will swing by to retrieve it on Saturday, two days before their mission ends.
Monday was the second straight day of robot-arm work for the crew.
Astronauts Jan Davis and Stephen Robinson used the experimental 5-foot arm to repeatedly lift a 11/2 -foot box out in the cargo bay. Japan's space agency developed the jointed, remote-controlled arm, a prototype of what will fly on the future international space station.
Japanese program manager Masanori Nagatomo said he was pleased with the results despite all the interruptions caused by overly strict safety restrictions. Such tight limits won't be necessary on the space station, he said.
Canadian astronaut Bjarni Tryggvason took time out to answer questions from students at a space camp in Saskatoon, Saskatchewan: Yes, his back hurts a little because of an elongated spine, the result of weightlessness, but he has gotten over his motion sickness.
"I was green on the second day of the flight, but I managed to do all of my work," Tryggvason said.