Mystery force on Moon may ‘run’ Apollo station

Press, Volume CXVI, Issue 34146, 6 May 1976, Page 10

Mystery force on Moon may ‘run’ Apollo station

(By

BOYCE RENSBERGER.

of the "New York Times")

A mysterious force on the Moon has been perplexing space scientists in recent months by making one of the remo t e-co n t rolled seien - tific stations set up by Apollo astronauts behave peculiarly.

The station, which had been working on the lunar surface without interruption since it was placed there in February 1971, went dead, then spontaneously returned to life a few weeks later, working better than ever, and then went dead again. Engineers at the Johnson Space center near Houston are now waiting to see whether the unknown influence acts on the station again to switch it back on. “It’s a bit of a mystery,” said Charles R. Redmond, a Houston-based spokesman for the National Aeronautics and Space Administration. "We have a number of people trying to figure out what’s happening up there but we haven’t got an answer yet.”

The station, established on the Apollo 14 mission, is one of five deployed at various sites on the moon at intervals since November 1969. Until this recent incident, all had been going uneventfully, sending back a steady stream of scientific data on such things as moonquakes, the amount

iof heat flowing out of the moon’s interior, and the nature of particles blowing in .the solar wind. i Although the stations, called A.L.S.E.P.s. for Apollo Lunar Scientific Experiment Package were first thought to have a lifetime of one year, their atomic power supplies have proved more durable. The mystery began in March 1975 when the Apollo 14 station’s receiver failed, cutting it of from radio commands from ground controllers. Last January 18 its transmitter suddenly stopped working and nothing was heard from the A.L.S.E.P. until February 19 when, just as suddenly, the entire station came back to life.

Not only did both the transmitter and receiver resume working but one of the experiments that had never worked during the heat of lunar daytime was also now operating flawlessly night and day. Then, exactly a month later, the mysterious force shut the whole station down again.

One theory, Mr Redmond said, is that the start and stops are related to extreme changes in temperature. In the daytime the moon’s surface is 250 degrees Fahrenheit, but after nightfall it drops to 300 degrees below zero. The A.L.S.E.P. has tended to die during the heat of the day and to revive

lat night. “.We’re waiting for midnight again—around April 19,’’ Mr. Redmond said. “We’re hoping it’ll come back on then... Because day and night have been occuring on the moon throughout the station’s lifetime, no one knows why the temperature change, if that is the cause, did not produce its effect from the start. Despite the problem, the scientists at various universities and research centers continues analyse data from the working lunar stations. One of the most important types of information comes from the seismometers that detect moonquakes. Several thousand small ones are recorded each year, most because of expansion and contraction of the crust as a result of alternate heating and cooling.

None of the shocks have penetrated to the moon’s core and from there to the detectors, where they could give signals that could help elucidate the nature of the core. Scientists are hoping a meteorite big enough to do this hits the back side of the moon before the stations die. Recent improvements in earth-based receivers have given scientists better data from the heat-flow experiment and. using this, new calculations have been made that modify an earlier interpretation. From the amount of heat generated within the

I moon, it had been estimated it was three times as radioactive as the earth, suggesting the two bodies were not derived from the same primordial source matter. Now it appears the difference is not so great, making similar origins more likely. Although most scientists would prefer to have their experiments executed during an A.L.S.E.P.’s prime, one has been put off until near the end of its station’s life expectancy, three years from now

It is a mortar, intended to be fired on command and to explode on impact some distance away. The idea is to set up shock waves in the ground that can be detected by the seismometers.

Three other mortars were fired successfully long ago but they jostled the launcher so much that, according to data received in Houston, the fourth mortar is no longer aimed where it was supposed to be. The scientists hope there is an error in the settings they are seeing because they indicate the mortar is now aimed at the A.L.S.E.P.’s central power ( and transmitting station.