Skylab's New Crisis: A Rescue Mission?

It was early morning in Houston when the first hint of trouble came. Watching his instrument console, an engineer on duty in Mission Control noticed an unusual temperature drop in the fuel system of one of the clusters of little steering rockets on the Apollo command and service modules (CSM) that had carried the second Skylab crew to their orbital home on July 28 and is needed to ferry them back to earth. About fifteen minutes later, the astronauts themselves became aware of the problem when an alarm went off aboard the space station, jolting them out of their sleep. Later, as they looked out of the window, they saw sparkling particles streaming by the orbital workshop. Said Skylab Commander Alan Bean with the coolness of a lunar-landing veteran: "We thought that was unusual." So it was. The temperature drop and the particles signaled a crisis that could lead to the first rescue mission in the history of space flight.

Controllers quickly determined the cause of the symptoms: a line from the tank containing the oxidizer necessary to fire the thrusters had apparently sprung a leak. That mishap--coupled with the earlier loss of oxidizer from a unit in one of the other four-nozzle clusters when a valve jammed during rendezvous with Skylab--left the ferry craft with part of its attitude control system not working. For several nerve-racking hours last week, NASA officials contemplated bringing the second crew of Skylab astronauts home immediately, lest any further deterioration in the Apollo rocket control system jeopardize their chances of a safe splashdown. By week's end the space agency had settled on a different course. For the time being at least, the Skylab team would be allowed to continue its record-breaking 59-day mission. As a safeguard, however, round-the-clock work was ordered at Cape Kennedy to prepare another Apollo craft for a rescue mission.

Skylab's most recent problem came only a day or so after Bean and Space Rookies Jack Lousma and Owen Garriott had finally overcome a bad case of motion sickness brought on by their exposure to zero G. During the initial stages of their mission, the crewmen--especially Lousma, who vomited several times--were barely able to perform routine housekeeping and experimental chores. But their "stomach awareness," as NASA euphemistically called it, was quickly overshadowed by the oxidizer leak.

The loss of the thrusters on Apollo's service module was not in itself critical. Experience in NASA'S ground simulators has shown that an Apollo spacecraft can be steered with only one service-module rocket cluster--or even with only the thrusters on the command module. What worried space-agency engineers was the possibility of further deterioration in the propulsion system. The small thruster systems, as well as Apollo's big main engine at the rear of the service module, use the same type of oxidizer. What is more, the chemical had come from the same batch at Cape Kennedy. Thus, if it contained some contaminant, all of the spacecraft's engine systems might well be imperiled.

Space Walk. Shortly after the trouble was identified, Christopher C. Kraft Jr., the Johnson Space Center's director, put in a call to Cape Kennedy: How soon could a rescue vehicle be made ready for launch? He also checked with NASA headquarters in Washington about such a mission. By midmorning, after emergency meetings in Washington, Houston and the Cape, Kraft had his answers. A three-shift, 24-hour-a-day operation could get a rescue vehicle (actually the command ship originally designated to be used by the third Skylab team) ready for launch by September 10. NASA headquarters also approved the cost: at least an extra $2,000,000.

As the order went out to begin the preparations, the shape of the proposed rescue became clear. Cape Kennedy's Pad 39B would have to be hastily readied for another launch. The Apollo rescue ship would have to be stripped of other gear to accommodate five passengers instead of the usual three and ballasted with 1,000 lbs. of lead to compensate for the resulting shift in the center of gravity. Astronauts Vance Brand and Don Lind, back-up Skylab crewmen, would pilot the craft to a rendezvous with Skylab and probably dock in an emergency port at the side of the space station (see chart). The three Skylab astronauts would then eject the disabled Apollo from the docking module to make room for the third crew, which NASA still optimistically hopes to send up in November.

The final decision to launch the unprecedented rescue mission will not be made until early in September. At week's end, in fact, space-agency officials were still hoping that there would be no need for it at all. For one thing, chemical tests at the Cape on samples of the oxidizer used for the Skylab mission showed that it was not contaminated and probably not responsible for the leak. Commented Kraft: "You always end up preparing yourself for the worst and you usually end up in a better position." He also sent word to the Skylab crew that they were still "go" for a full mission.

Said the elated Bean: "That's what we've been hoping you would say." In fact, the astronauts got ready to take their repeatedly postponed space walk early this week. That will enable them to erect a second sunshade over the area stripped bare when a micrometeorite shield ripped off during Skylab's launch in May. The astronauts will also take the opportunity to reload their solar-telescope array with fresh film. Underscoring the renewed optimism at Houston that Skylab would survive this latest crisis, Kraft made arrangements to bring Soviet Ambassador Anatoly Dobrynin to Houston at week's end for a look at operations inside Mission Control.

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