Our Spaceflight Heritage: Roving on the lunar surface with Apollo 15
On July 31, 1971, Apollo 15 astronauts Dave Scott and Jim Irwin became the first to use the Lunar Roving Vehicle (LRV), traveling more that 17 miles on the surface of the Moon. LRV was a four-wheeled, manually controlled, electrically powered vehicle that carried the crew and their equipment over the lunar surface. Apollo 15 was the first of the longer expeditions to the moon, where we actually began to explore the terrain in some detail.
The primary objectives assigned to the Apollo 15 mission were as follows:
- to perform selenological inspections, survey and sampling of materials and surface features in a preselected area of the Hadley-Appennius region;
- to emplace and activate surface experiments;
- to evaluate the capability of the Apollo equipment to provide extended lunar surface stay time; and
- to conduct inflight experiments and photographic tasks from lunar orbit.
Apollo 15 was launched from NASA Kennedy Space Center at 9:34:00 a.m. EDT (13:34:00 GMT) on July 26, 1971. The combined command-service module (CSM), lunar module, and SIVB booster stage were inserted 11 minutes, 44 seconds later into an Earth orbit of 91.5 × 92.5 nautical miles. After normal systems checkout in Earth orbit, translunar injection was accomplished 2 hours, 50 minutes after launch.
Because of the variety of surface features, the Hadley-Apennine landing site permitted extensive geological exploration.
During the approximately 67 hours on the Moon, the crew conducted a 33-minute stand-up extravehicular activity (EVA) in the upper hatch of the of the lunar module as well as three EVAs totaling about 18.5 hours on the lunar surface.
Improvements to the Portable Life Support System used with their space suits allowed the crew to perform longer EVAs (up to 7.5 hours) than was possible on earlier missions.
During these EVAs, they performed lunar rover traverses totaling nearly 17 miles (28 km), collected samples at 12 locations, deployed 10 experiments, and photographed the lunar surface.
Apollo 15 was the last mission on which a contingency sample was collected. The sampling consisted of seven samples taken approximately 12 meters west of the lunar module footpad.
The site is a small flat area between two subdued 1-meter-diameter craters. This sample was collected to ensure that some lunar material would be returned for study on Earth in the event that an emergency required the rapid, unplanned end to the EVA.
The increased mobility using the LRV and ease of the travel made possible by this vehicle permitted the crew to travel much greater distances than on previous lunar landing missions. The vehicle was designed to carry the two crewmen and a science payload at a maximum velocity of about 8.6 mph (16 kph) on a smooth, level surface and at reduced veolocities on slopes up to 25 degrees. It could be operated from either crewman’s positions, as the control and display console was located on the vehicle centerline. The deployed vehicle was appoximately 10 feet long, 7 feet wide, and 45 inches high. Its chassis was hinged such that the forward and aft sections folded back over the center potion, and each of the wheel suspension systems rotated so that the folded vehicle would fit in quadrant I of the lunar module. The gross operational weight was approximately 1535 pounds, of which 455 pounds was the weight of the vehicle itself. The remainder was the weight of the crew, their equipment, communications equipment, and the science payload.
After returning to the lunar module, the astronauts prepared for leaving the Moon. They retrieved the Solar Wind Composition foil and canceled the First Day Issue stamp. They performed the hammer and feather drop. They parked the lunar rover and positioned it to obtain color television coverage of the LM ascent. As their final act, they placed a memorial to “fallen astronauts” in a small crater about 20 feet north of the parking site.
On August 2nd, Falcon fired its ascent stage engine and lifted off the moon for its rendezvous with command module, Endeavor. For the first time, the lunar liftoff was seen on Earth via the LRV television camera. During the return flight aboard Endeavour, Worden became the first man to perform a space walk outside of earth’s orbit as he went outside to retrieve some film from the side of the space craft.
Apollo 15 set several new records for crewed spaceflight: heaviest payload in a lunar orbit of approximately 107,000 pounds, maximum radial distance traveled on the lunar surface away from the spacecraft of about 17.5 miles (previous high was 2.1 miles on Apollo 14), most lunar surface EVAs (three) and longest total of duration for lunar surface EVAs (18 hours, 37 minutes – almost the total time spent in lunar orbit by Apollo 8), longest time in lunar orbit (about 145 hours; only two hours less than the entire Apollo 8 mission), longest crewed lunar mission (295 hours), longest Apollo mission (295 hours – previous high was 244 hours, 36 minutes on Apollo 12), the first satellite placed in lunar orbit by a crewed spacecraft, and first deep space and operational EVA.
They collected over 170 pounds of lunar samples to bring back to Earth.
Heather Smith's fascination for space exploration – started at the tender age of twelve while she was on a sixth-grade field trip in Kenner, Louisiana, walking through a mock-up of the International Space Station and seeing the “space potty” (her terminology has progressed considerably since that time) – she realized at this point that her future lay in the stars. Smith has come to realize that very few people have noticed how much spaceflight technology has improved their lives. She has since dedicated herself to correcting this problem. Inspired by such classic literature as Anne Frank’s Diary, she has honed her writing skills and has signed on as The Spaceflight Group’s coordinator for the organization’s social media efforts.