Shuttle nears goal: smooth, regular operation

America's Space Transportation System (STS) is about to come of age as an operational fleet of spacecraft. The shuttle Challenger, now being refurbished after its recent six-day mission, is to fly again in January. Meanwhile, its sister ship, Columbia, is ready to orbit the European-made Spacelab Oct. 28. And, on Oct. 1 - the 25th birthday of the National Aeronautics and Space Administration (NASA) - a third shuttle, Discoverer, is scheduled to roll out of the factory and join the fleet.

Discoverer's first mission - the 12th in the STS series - is to take place next May, 1 of 11 missions scheduled for 1984. There should be 16 flights the following year, when the fourth shuttle, Atlantis, enters service. NASA expects a rate of 24 missions a year by 1987.

Thus 1983 marks the transition from the initial shakedown of the shuttle system to its full operational status.

At this writing, it was uncertain how much action Columbia would see over the next two years. NASA is studying the possibility of keeping Columbia out of service for perhaps 18 months after the Spacelab flight. Among other things, it would be used as a source of spare parts for the other orbiters. Shuttle program manager Lt. Gen. James A. Abrahamson has acknowledged a spare-parts shortage. He attributes it to tight funding earlier in the shuttle program.

Meanwhile, shuttle missions now will begin to use more of the full STS range of capability. The Spacelab mission will show what an orbiter can do as a temporary work station. The six-man crew - the largest yet to go into space - includes working laboratory personnel.

Then in January, during the STS-10 mission (to use shuttle jargon), Bruce McCandless is to try out the astronauts' new jet-propelled backpack. With this, he is to maneuver as much as 300 feet from Challenger. It will be the first untethered excursion outside an orbiter.

On the following flight in March, George Nelson will again use the backpack. This time, he will try to secure the ailing Solar Maximum Satellite so it can be brought aboard the shuttle for repair. Success in this mission would show the value of the shuttle as a repair and engineering platform.

Next year should also bring completion of the Tracking and Data Relay Satellite (TDRS) system. Challenger's crew found the first TDRS useful in maintaining longer periods of communications with the ground during their recent flight. With two TDRS on station, shuttle crews should have almost continuous communications.

Parked in an orbit 22,300 miles high. the TDRS relays have a clear view of the orbiter. By May, when Discoverer makes its maiden flight, the Air Force expects to have fixed the trouble with the booster rocket that put TDRS-1 in the wrong orbit after it was released from the shuttle last April.

With this kind of schedule ahead of it, the STS program is taking on the character NASA has long planned. It is becoming an effort as routine and smooth running as an airline operation.

Space America

Three US companies have joined together to launch their own resource satellite system. They call it the Space America program.

American Space and Technology Corporation, AEROS Data Corporation, and Space Services Inc. plan a system of three remote sensing satellites. The first launch is to be in 1986 with two subsequent launches at two-year intervals. Space Services' Conestoga II rockets are to be used.

The consortium hopes to sell its data worldwide to governments and companies interested in prospecting, food production, water-system management, and other activities that would benefit from a space-eye view.

This would put the consortium in direct competition with the US Landsat system. However, the Reagan administration wants to sell that system, although there is strong congressional opposition to the sale. The consortium says it will submit a bid.

There are many uncertainties besides normal business risks in starting up such a commercial venture. For one thing, the Department of Defense has said it wants to restrict any such operation so that it does not sell pictures that might show too much detail of US military installations. Also, the State Department warns that it would want to restrict operations that might give away US technology to the Soviets. This would restrict receiving stations to countries outside the Soviet bloc.

First American farmers

Agriculture appears to have developed in the North American Midwest far earlier than has been supposed.

Using a new technique for dating organic material, James A. Brown and colleagues at the University of Rochester have dated squash seeds from Illinois as being at least 7,000 years old. The seeds appear to have come from cultivated plants. This makes agriculture in that area some 2,500 years older than had previously been suggested, according to an announcement from the National Science Foundation.

The dating technique is a refinement of radiocarbon dating. Living plants and animals absorb a radioactive form of carbon that occurs naturally in air. After they die, this carbon slowly decays. Plant and animal remains can be dated by comparing their radiocarbon concentration with that of standard samples. The new technique, which counts the actual number of radiocarbon atoms in a sample, is much more sensitive than earlier methods.