Apollo Expeditions to the Moon|
TAN DUST ON SURVEYORWe found some green rocks, and some gray soil that maintained its light color even below the surface, which is not common, and we finally reached the Surveyor crater. I was surprised by its size and its hard surface. We could have landed right there, I believe now, but it would have been a scary thing at the time. The Surveyor was covered with a coating of fine dust, and it looked tan or even brown in the lunar light, instead of the glistening white that it was when it left Earth more than two years earlier. It was decided later that the dust was kicked up by our descent onto the surface, even though we were 600 feet away.
We cut samples of the aluminum tubing, which seemed more brittle than the same material on Earth, and some electrical cables. Their insulation seemed to have gotten dry, hard, and brittle. We managed to break off a piece of glass, and we unbolted the Surveyor TV camera. Then Al suggested that we cut off and take back the sampling scoop, and so we added that to the collection.
Then we headed back to the Intrepid. We retrieved the solar- wind experiment, stowed it and the sample bags in the Intrepid, got in, buttoned it up, and started repressurization. Altogether we brought back about 75 pounds of rocks, and 15 pounds of Surveyor hardware. We also brought back the 25-pound color TV camera from Intrepid so that its failure could be investigated.
While we were busy on the surface, Dick Gordon was busy in lunar orbit. The Yankee Clipper was a very sophisticated observation and surveying spacecraft. One of the experiments that Dick performed was multispectral photography of the lunar surface, which gave scientists new data with which to interpret the composition of the Moon.
After Al and I got back to Yankee Clipper following lunar liftoff and rendezvous, all three of us worked on the photography schedule. We were looking specifically for good coverage of proposed future landing sites, especially Fra Mauro, which was then scheduled for Apollo 13. That's a rough surface, and we wanted to get the highest resolution photos we could so that the crew of the Apollo 13 mission would have the best training information they could get.
We changed the plane of our lunar orbit to cover the sites better, and we also elected to stay an extra day in lunar orbit so that we could complete the work without feeling pressured. We took hundreds of stills, and thousands of feet of motion-picture film of the Fra Mauro site, and of the Descartes and Lalande craters, two other proposed landing sites.
Meantime the experiments we had left on the lunar surface were busy recording and transmitting data. They all worked well, with one exception, and were really producing useful data. One unexpected result came from the seismic experiment recording the impact of Intrepid on the surface after we had jettisoned it. The entire Moon rang like a gong, vibrating and resonating for almost on hour after the impact. The best guess was that the Moon was composed of rubble a lot deeper below its surface than anybody had assumed. The internal structure, being fractured instead of a solid mass, could bounce the seismic energy from piece to piece for quite a while.
The same phenomenon was observed at two ALSEP stations when the Apollo 14 crew jettisoned their lunar module Antares and programmed it to crash between the Apollo 12 and 14 sites.
With every mission after Apollo 12, additional seismic calibrations were obtained by aiming the Saturn S-IVB stage to impact a selected point on the Moon after separation from the spacecraft. The seismic vibrations from these impacts lasted about three hours.
Apollo 13 was supposed to land in the Fra Mauro area. The explosion on board wiped out that mission, and it became instead a superb example of a crew's ability to turn a very risky situation into a safe return to Earth.
So the Fra Mauro site was reassigned to Apollo 14, because scientists gave that area a high priority. The following account is by Alan B. Shepard, Jr., the first American into space and of the original seven astronauts.
The Fra Mauro hills stand a couple of hundred of miles to the cast of the Apollo 12 landing site. I was selected to command this mission, my first since the original Mercury flight in 1961. With me to the lunar surface went Edgar D. Mitchell in Antares, while Stuart A. Roosa was the command module pilot of Kitty Hawk.