Mariner Ready For Pictures

Press, Volume CIV, Issue 30803, 15 July 1965, Page 15

Mariner Ready For Pictures

(N .Z .P .A.-Reuter—Copyright) PASADENA (California), July 14. Mariner IV streamed to within 110,000 miles of Mars today, all set for an historic picturetaking mission which may help answer some centuries-old riddles about the mysterious red planet. Australia and New Zealand both have a share in the exciting project. Tidbinbilla, just outside Canberra, is one of three major tracking stations. The others are at Goldstone, California, and Hartbeeshoek, South Africa. Dr. William Pickering, director of the project, is New Zealand-born. A ground station in Johannesburg will send out the command signal at 2.15 a.m., July 15, New Zealand time, to start the spacecraft’s camera platform bobbing up and down in a 10-hour warmup period. This will give scientists at Pasadena the chance to check the operation of the camera, the sensors “looking” for the approaching planet and the tape recorder. At 12.20 p.m. Mariner’s television cameras will convert the scene on Mars some 6000 miles below into about 21 sets of electronic signals to be stored on the tape recorder.

They should show a strip of Mars from north of its equator down, in a southeasterly direction, across its south pole.

The camera is set to run for 25 minutes as it crosses the planet before entering the Martian night. Twelve hours later, when

the craft emerges from behind the planet, the taped pictures will be transmitted to earth —very slowly, to avoid garbling of signals over the 134-million-mile void.

Engineers at the Jet Propulsion Laboratory said each transmission will take eight hours 35 minutes to arrive on earth.

As preparations stepped up

in the Jet Propulsion Laboratory, its director. Dr. Pickering, warned against expecting too much from the pictures. “We don’t hope for really first-class pictures such as the Ranger spacecraft sent back from the moon. These will be much less elaborate pictures,” he said. Ten Days

He said it will take 10 days altogether to get the complete set of pictures radioed back to earth. They are expected to show detail 100 times better than pictures of the planet taken through the most powerful telescopes on earth. One scientist remarked last night: “It will be a miracle if all goes well.” Even if there are no pictures, J.P.L. scientists will be hanpy enough with the volumes of scientific data Mariner IV has so far radioed back about the deep-space environment it has cruised through. And they know that its magnetic detectors are working well enough to be able to tell them as it passes Mars whether the planet has a magnetic field and whether that

field has trapped high-energy radiation in the same way as the Van Allen belts around the earth. Another new and valuable fact about Mars should also come from an experiment ranked almost as important as the picture-taking—the effect of the Martian atmosphere on Mariner TV’s radio signals as the spacecraft passes behind the planet. The spacecraft will be blacked out from radio contact for 52 minutes when this happens, but just before and just after this event, its radio signals will have to pass through the thin atmosphere believed to surround Mars.

They will be bent slightly by this atmosphere and a careful measurement of this effect should provide scientists with a clue to the density of the air.

Scientists fear it is too thin to give lift to wings and parachutes as earth’s atmosphere does—an important point for the men designing the spacecraft which will land instrument packages and later astronauts on Mars in the next 20 years.