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Other-World Mission. Operated for NASA by Caltech, Pasadena's Jet Propulsion Laboratory, which has been in on the U.S. space game from its inception, has franchise described by its director, brilliant, balding Dr. William Pickering, in otherworld terms: "Our mission is the exploration of the moon, the planets anc interplanetary space." In determined pursuit of that mission, Pickering's J.P.L. is working toward a series of space shots, currently planned at five, known as the Ranger series and scheduled to begin in null
Boosted by Atlas missiles. Ranger's second stage will be an Agena-B rocket on top of which will sit what J.P.L. calls an "all-purpose bus." It looks a little like a squat oil well derrick hung with antennae, solar-cell paddles and other odd-looking gadgets. Inside is a shrewd little electronic brain and a gas-jet attitude-control system based on the space capability of the Discoverer series. The most interesting Ranger shots, those intended to land instruments on the moon, will also have one-start hydrazine engines for course correction.
During the launch, the bus will be shrouded to protect its fragile structure from air blast, but as soon as it is safely in space, the shrouding will come off. The bus will separate from the second-stage rocket, and its brain, which contains a preset program of the maneuvers that the bus must perform during flight, will go into action. Its first command in effect will tell the gas jets: "Turn this bus until its two solar panels see the sun equally. Then keep it that way."
When the gas jets obey, the long axis of the bus will be pointing properly at the sun. and the brain will tell the jets to roll the bus around that axis until its dish antenna is pointing at the earth, sending reports and intently listening for orders. In twelve to 17 hours, the first command will arrive. It will tell the brain to make the gas jets tumble the bus into a new and carefully calculated attitude. Then the bus, its course corrected for a collision with the moon, will turn again to look at the sun and point its antenna backwards at the earth.
Soft Moon Impact. During its last hour of falling toward the moon, the bus will turn its bottom downward. A gamma ray spectrometer will go into action, reporting to earth the kind of radioactivity on the moon's surface and giving some idea of its material. A TV camera will take pictures every twelve seconds and transmit them to the earth. At about 100.000 ft. above the moon's surface, an electronic altimeter will tell a 300-lb. survival package (because it is part of the Ranger system, the package inevitably has come to be known as "Tonto") to separate from the rest of the bus. The survival package, slowed by a solid-propellant retrorocket, should land on the moon at something like 70 m.p.h. This is the purpose of the voyage: to set a package of instruments on the moon without too much of a jolt.