Far-out Planets In U.S. Space Planning

Press, Volume CVI, Issue 31339, 8 April 1967, Page 5

Far-out Planets In U.S. Space Planning

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NEAL STANFORD0

WASHINGTON.

The United States has no commitment to put astronauts on Mars, as it has to land men on the moon. But it has plans, blueprints, schedules, programmes, and volumes of data on how to do it, perhaps in the 1980 s. It also has much more specific plans for trips to Mars and other planets.

This all came out this last week (March 14-21) in a two-day symposium in Washington, staged by the i American Astronautical Society, on the interesting subject: “Voyage to the planets.” Most of the speakers were top officials of the National Aeronautics and Space Administration. NA.SA. has yet to put men on the moon—but it is thinking (and has been for some time) of either manned or unmanned spacecraft visiting Mars, Venus, Jupiter, Saturn, Uranus, Neptune, comets, asteroids, the sun—and even beyond the solar system. If this all sounds fantastic, incredible, improbable, space officials say one has only to think back a decade or two when talk of a moon trip was pure science fiction. Few persons dreamed that by 1967 men would have orbited the earth, walked in space. So one should not belittle today’s space dreamers, even though Congress is not voting any money for manned planetary trips. Space scientists, however, are working on them. Planetary Fly-bys

Sending unmanned spacecraft flights to the planets really will be nothing new. The United States has done it twice. In 1962 it sent a Mariner spacecraft on a fly-by to Venus. Then in 1964 it flew another Mariner by Mars. It picked up a lot of valuable information from these planet flybys. It discovered in the Venus flight, for instance, that the surface temperature was between 600600 degrees F. (too hot for astronauts to land); in the Mars fly-by, that its surface was cratered like the moon.

It is planning more planetary fly-bys, starting this year —trips for which there is hardware, and dates are set Space officials have roughed out unmanned flights to the planets for the next decade. Manned flights come later. Plans for the next five years are fairly firm. Those for the second five years are tentative. Two Spacecraft Two kinds of spacecraft will be used in these unmanned flights to the planets: the Mariner series; the Voyager series. The Mariners will make the first planetary probes. They use the AtlasAgena or Atlas-Centaur vehicles to boost them on their

space flights. The Voyagers are the second-generation planet

spacecraft—larger, and improved. They will use the mighty Saturn 5 vehicle as booster. The Mariners either can make fly-bys of the planets or an atmospheric probe. Hie voyagers are expected to orbit the planets, and some even soft-land. Thus tiie first planet shots will be Mariners; the later ones, Voyagers.

Spacecraft flights to the planets cannot be scheduled to suit the planners. There are only certain launch opportunities. This is the result of the different orbits of the planets around the sun, and the frequency with which the orbiting earth comes closest

to the various planets. Space distances being what they are, one picks the time for .a Mars or Venus shot, for example, when the planet is orbiting closest to the earth—not when it is on the other side of the sun from the earth.

Few Opportunities Thus, favourable launch opportunities come infrequently. And that explains why in their programming space officials have the timetables they have for planetary shots. Here is the picture as they have it now: In 1967 a Mariner Venus fly-by.

In 1969 a Mariner Mars mission.

In 1971 a Mariner Mars flight to include an entry shell to the planet’s surface. In 1972 a mission to Venus and entry probe. In 1973 a unique Venus launch that will also include a fly-by to Mercury. In this flight the position of other planets makes it possible to explore more than one planet at a time—using what is called a “gravity assist” of the second planet to make a dual shot.

In 1975 a Voyager orbiter and lander to Mars.

The period of 1970-1976 is also estimated to be a good time to study the comets—to learn more about these vagrants of the solar system. A Mariner would be directed 1500 miles or so behind the comet, the purpose being to observe the central core of the comet bead from its wake. Two of the most noteworthy comets space officials are aiming to study are D’Arrest’s comet that passes in range in 1976, and Halley’s comet which returns in 1984. When officials get the mightly Saturn 5 as booster for Voyager spacecraft they are going to be able to throw two Voyager systems at Mars at one time. The two would go into Martian orbit separately, spends days or weeks looking for suitable landing sites, and then release their capsules for a soft landing. Looking For Life One of the things they are looking for, of course, is any sign of extraterrestrial life. One reason why Mars gets preference over Venus for planetary exploration is that the prospects of finding signs of life on Mars seem better than on Venus.

In connexion with a try for a look at the planet Jupiter some five years off, space scientists think it may be possible after flying by Jupiter to escape the gravitational dominance of the sun and go beyond our solar system.

Projected For 1970 s Then in the year 1977-78 they speak of a “grand tour” visit to Saturn, Uranus, and Neptune, possible because of the relations of these planets to each other at that time. The gravitational pull of the various planets again would be used to reshape the course of the spacecraft to enable it to fly to other planets. It is pointed out that there is a Mars and Jupiter that could damage a spacecraft. Another projected flight for

i sometime in the early 1970’s would go past Mars and beyond Jupiter, using Jupiter’s pull to cancel the spaceman’s ; velocity around the sun. The probe then would impact the ■ sun. It is apparently impossible with the vehicles now on hand, even the powerful Saturn 5, to send a payload directly into the sun. Manned Flights When it comes to manned flights to the planets, space officials are less precise but no less confident They say they see no technical reason why man cannot fly to Mars, alight, and return—and to Venus, if its temperatures permit such a visit But such trips will take a year or more. And that is why in the very elementary efforts now being made to accommodate man to life in space the time limit is constantly being extended. 670-Day Trip Astronauts have spent up to two weeks in space without apparent dangerous physical or psychological results. But before man can go to Mars or Venus he must learn to live in space for up to two years. A Mars or Venus visit would take in the neighbourhood of 670 days. That is why N.AS.A. is so anxious to get on with the workshop project that would permit the use of the spent S-4B stage of the Saturn 5 as an earth-orbiting laboratory. Men would progress from the present two weeks spent in space to 28 days, to 56 days, and by 1970 or so to a year. How To Keep Busy The time period envisaged for manned flights to Mars is in the 1980 s, if Congress approves these long-range and extended manned space flights. One problem is what six to 10 men in a spacecraft l headed for Mars would do in - the 15 months or more it 1 would take to get there. They ' must not only be kept alive 1 but busy. i It takes a brave man these < days, what with the difficulties that have cropped up in tiie 1 Apollo manned moon shots, to < speak with confidence of man- ; ned trips to Mars, Venus, and ; beyond, even 15 to 20 years 1 off.—Reprinted by arrange- < ment from the “Christian Science Monitor.” (