The Shuttle Story: Short but Sweet

Despite a malfunction that cut its mission in half, scientists at NASA and Harvard say last week's flight of the space shuttle Columbia--the first spacecraft to be re-used--was a success, and that data from on-board experiments will reveal valuable information about the earth's natural resources.

Columbia's flight was "reasonably successful, considering everything," Alistair G.W. Cameron, chairman of the Astronomy Department and associate director of the Harvard-Smithsonian Center for Astrophysics, said this week. "One has to expect all sorts of things will go wrong on these test flights, and that's what they're for," he added.

While National Aeronautics and Space Administration (NASA) officials are disappointed that the Columbia had to come home Saturday, three days earlier than planned, astronauts Joe Engle and Richard Truly still accomplished almost 90 per cent of the mission objectives, NASA spokesman Terry White said Monday.

Besides putting the orbiter itself through a rigorous series of maneuvers, Engle and Truly conducted several successful tests of a 50-foot mechanical arm, which on future missions will be used to retrieve satellites for in-flight servicing or later repairs on earth, and to deploy payloads from the shuttle's cargo hold. On this mission, the 15-foot by 60-foot cargo bay held its first scientific payload, with experiments designed to study a variety of geologic, atmospheric, and oceanic features.

Designated OSTA 1, for NASA's office of space terrestrial applications, the payload contained several instruments to help scientists refine their techniques for observing the earth from space, and for identifying untapped mineral, gas and oil deposits.

The first of these instruments is the feature identification and location experiment (FILE), which examines the brightness of such features as vegetation, water, desert areas, snow, or cloud cover, using light sensors and television cameras. By classifying each feature in terms of its brightness reading, scientists can use FILE information to select which objects they want to focus on. Essentially, FILE acts as a data censor, and is one solution to the problem of land observation satellites continuing to collect unnecessary data even when clouds block their view.

Also on the Columbia were two devices designed to map various geological resources. An imaging radar, a 30-foot long rectangular antenna, bounced sonar waves off terrain and oceans to produce images of the reflecting surfaces. And a multispectral radiometer scanned selected areas at ten infrared wavelengths.

Scientists hope to use the data from both the imaging radar and the radiometer, combined with pictures from Landsat satellites, to identify the most useful infrared band for surveying specific minerals.

As the astronauts recorded the occurrence of lightning for weather analysts, instruments checked the amount of carbon monoxide at different levels of the atmosphere and monitored the rate of growth of sunflower seedlings in the weightless environment.

Finally, the ocean color experiment (OCE) scanned ocean areas for traces of chlorophyll, the green pigment in plants. The presence of chlorophyll would indicate the location of marine plants and large concentrations of fish, information of great interest to commercial fisheries.

The OCE is a "very fancy color camera" that makes "homogeneous observations over an entire ocean basin," Richard M. Goody, Mallinckrodt Professor of Planetary Physics, said this week, adding that by mapping an entire ocean surface at the same time, oceanographers can obtain "data that has never been available."

For the future exploration of world oceans, these experiments will be revolutionary," Goody said.

NASA engineers believe that a "re-grouping" of objectives into the shortened flight plan provided them with more than half the expected OSTA 1 data, even though Columbia's second mission was 54 hours and 36 orbits, instead of a planned 124 hours and 83 orbits, spokesman White said. Shuttle managers will not know exactly what data they missed, however, until debriefing meetings with the astronauts and flight controllers begin tomorrow.

One test that was eliminated from the mission was a rehearsal for an emergency space walk, which would have been performed if automatic devices to close the four payload-bay doors failed to work, or if the robot arm had malfunctioned.

Post-flight inspections of the thermal protection system, a blanket of 31,000 silica tiles which protects the 122-foot long orbiter from the heat of reentry, revealed only minor damage and no missing tiles, White said. The tiles had been a problem on Columbia's first flight in April, and were a source of many of the delays that set the $10-billion shuttle project more than three years behind schedule.

Engineers have yet to examine the electricity-producing fuel cell that failed soon after a perfect launch from the Kennedy Space Center last Thursday, causing the flight to be shortened. White said the cell will be analyzed when the shuttle is returned next Wednesday to Cape Canaveral, Fla., from Edwards Air Force Base, Calif., where Engle and Truly brought Columbia to a pin-point landing Saturday afternoon.

As a platform for scientific observations, the shuttle "may not be absolutely perfect for purposes of astronomy, but it is clear that it is the only main line of development that we have," George B. Field, Paine Professor of Practical Astronomy and director of the Harvard College Observatory, said this week. Terming the flight a "limited success," Field added that the main purpose of the test flights is to "prove out" the shuttle systems.

The curtailed mision, White said, will "probably not affect" planning for the third orbital test flight, scheduled to be launched next March on a seven-day mission. A more extensive test of the manipulator arm is planned for the third flight, which will carry a payload of astronomical sensors. After a fourth flight in June, the shuttle will begin operational flights in which the primary mission objective will be to carry payloads, rather than to test the capablities of the vehicle.