Sunday, January 4, 2009

Surveyor proved the Moon safe for man

This week in space history
Alamogordo Daily News
By Michael Shinabery, New Mexico Museum of Space History

Before America's astronauts ventured forth onto the moon, robotic craft surveyed the surface to ensure the first man to walk there wouldn't sink like quicksand. The seven spacecrafts were, appropriately, named Surveyor. NASA designed them beginning in 1960 when the agency was just two years old.

Launched from 1966-68, not all of them landed successfully. But Surveyor VII did after leaving Earth 41 years ago this week, on Jan. 7, 1968. The flight was purely scientific. The robot took 21,033 photographs over 21 months, and the television camera, for the first time, photographed dual laser beams aimed from Earth.

Surveyor VII landed in the southern highlands. Scientists had recommended the area "near the crater Tycho," in 1967, states a Jan. 4, 1968, NASA release in the New Mexico Museum of Space History archives.

The release says the area was as "geologically different as possible from the lowland mare sites investigated by previous Surveyors." Because four of the first six missions did prove surface stability, "Apollo manned lunar landing officials were satisfied that man could land in the area where Apollo would be aimed," an undated document in the museum archives states. Thus "the Surveyor VII mission Š would attempt to land away from the smooth lunar maria, or 'seas,' and try the rougher highlands." A UPI telephoto taken by Surveyor VII shows the moonscape along Tyco's northern rim crammed with boulders. The cutline describes the area as similar to "a western movie scene."

Hughes Aircraft built the Surveyors. NASA awarded the contract on March 1, 1961. In a booklet printed after Surveyor II and pre Surveyor III, Hughes stated Surveyor VII's goals included radar reflectivity studies, as well as the gathering of thermal data.

All Surveyors were similar. Documents in the museum archives state they weighed 2,200 pounds at Earth liftoff. Once on the moon, after using fuel and shedding guidance and landing equipment, the robotic craft weighed only 600 pounds. The robots were 11 feet high. Their three deployed legs splayed 15-feet in diameter.

Of the preceding six missions, Surveyor I transmitted data and 11,000 photographs, including the first color images from the moon, for 220 days. Homer E. Newell, Ph.D., then NASA associate administrator for Space Science and Applications, wrote in "National Geographic" (October 1966) that among the images was a massive field of small rocks to boulders up to three-feet wide. The material, he said, was "ejected by the constant barrage of meteorites cratering the moon's surface, or rubble thrown out of secondary craters created by the impact of the original flying debris."

Newell said that, among Surveyor I's many triumphs, the craft "proved its ability to survive the furnace heat of the lunar noon, then go through the deep freeze of the 14-day-long lunar night at temperatures nearly 500 degrees colder, and still operate." He wrote that, over the first 14 days alone, Surveyor I executed "more than 100,000 earth orders during the two-week-long lunar day."

A less tangible result, but no less important, was peace of mind.

"For the first time, because of Surveyor, Project Apollo officials feel real assurance that an astronaut can safely set foot on the moon, that the moon's surface will support him, and that he will not be swallowed up in a thick sea of dust," Newell said.

Surveyor II never had the chance to perform. The craft crashed when a stabilization engine, called the Vernier engine, "failed to ignite," according to the Web site The undated document in the archives explains how the Vernier engines stabilized the craft during descent, while retro-rockets fired, slowing the Surveyors "to (three) miles an hour and (bringing the craft) within 14 feet of the surface." Honeycombed blocks and pads cushioned the landing.

Surveyor III took 6,315 photographs, "and its soil sampler made pressure tests, dug small trenches, and picked up several rock-like objects," the undated document states.

Surveyor IV failed when reports the craft lost radio contact 2-1/2 minutes from touchdown.

Surveyor V landed in the Mare Tranquillitatus, or Sea of Tranquility, the Apollo 11 site where Neil Armstrong would be the first to walk on the moon. Surveyor V nearly crashed when pressurized helium, which forced fuel into the Vernier engines, leaked. This mission chemically analyzed the soil.

Surveyor VI took 30,065 pictures and actually re-launched off the lunar surface. The undated document says the craft "rose 10 feet into the air and landed (eight) feet away. For the first time, a manmade spacecraft had lifted off under rocket power from another celestial body."

Dead batteries ended each of the successful missions. Since only Surveyors II and IV were failures, the Surveyor Project had a 71 percent success rate.

Michael Shinabery is an education specialist with the New Mexico Museum of Space History. Michael Smith, the Museum's registrar, contributed to this article.