mission. it s carrying up about 15,000 pounds of in fact, 15 tons of stuff on the leonardo cargo module up to the space station. spare parts, new science experiments and one of the great things about the shuttle is it can return a lot of material from earth s orbit. they ll load leonardo up with a lot of trash and obsolete experiments and bring that stuff back at the end of the mission. that s important, tom. there are only a few missions left. i mean, a lot of people maybe aren t paying close attention to the fact that what s going to happen to nasa when there are no more missions? well, nasa has got a problem it s facing. when the shuttle retires after the four missions are up, it has a cargo problem, getting carid up to the space station. there s no way to get things back from earth s orbit in the size and volume that the space shuttle can offer. that problem has yet to be solved by nasa. it s one of the quandaries facing the space agency in the