Jul 29 1971
From The Space Library
July 29-August 4: Apollo 15 entered lunar orbit with 314.8-km (195.6-mi) apolune and 107.5-km (66.8-mi) perilune after LoI burn at 78:32 GET (4:06 pm EDT July 29). "This is really profound ... it's fantastic," Scott said of view from moon. Apennine Mountains looked unreal. "They stand out in tremendous relief. They appear to be smooth or rounded. But they are cratered and in many places rough in texture. We don't see any jagged peaks. They don't look like ... any other mountains we've seen on earth."
CSM-LM undocking and separation maneuver was initiated during 12th lunar revolution, on far side of moon at 100:14 GET, but spacecraft did not undock, Worden entered tunnel to inspect CSM-LM umbilical and found plug was loose. After he reconnected plug and adjusted spacecraft attitude, undocking and separation were achieved at 100:39 GET-about 25 min later than planned.
LM Falcon touched down in moon's Hadley-Apennine region near Salyut Crater at 104:42 GET (6:16 pm EDT July 30) about 600 m (656 yds) north-northwest of planned target. "OK Houston," Scott said after touchdown, "the Falcon is on the plain at Hadley." He said LM's engine had stirred up so much dust that landing site had been completely obscured from 15-m (50-ft) altitude to touchdown: "We flew IFR from then on down."
Stand-up extravehicular activity (SEVA) to observe and photograph landing site and surrounding area began after cabin depressurization at 106:43 GET. Scott put his head out of upper hatch and described and photographed area for 33 min. Scott said he could describe site for hours. Area was covered with craters, but strewn with very few large boulders; it was hilly, but not rocky or rugged.
First EVA began July 31 at 9:04 am EDT. Scott climbed down ladder, deployed MESA containing camera which recorded his descent, and stepped on lunar surface. Irwin followed and, while Scott removed TV camera from MESA and deployed it on tripod, Irwin collected contingency sample. Crew had difficulty deploying LRV Rover; during check-out they found that front steering mechanism was inoperative and that there were no readouts on LRV battery No. 2 amp-volt meter. Battery was found to be operating satisfactorily and decision was made to perform EVA-1 without Lnv front-wheel steering. Crew mounted LRV and proceeded on EVA-1 traverse at 121:45 GET. Crew described EVA as "exploration at its greatest," and repeatedly used words "fantastic," "breathtaking," and "spectacular" to describe features as they rode LRV at about eight km per hr (five mph). Scott said Rover handled quite well: "It negotiates small craters quite well, although there is a lot of roll. The steering is quite responsive . . . and I can maneuver pretty well.. . There is no accumulation of dirt in the wire wheels." Stops at stations where crew collected lunar samples and took photos were broadcast on TV with excellent transmission. At end of traverse ALSEP was deployed. Scott and Irwin reentered LM after 6 hrs 33 min exploring surface, 28 min sooner than planned because Scott used up more oxygen than anticipated.
After resting inside LM, recharging and repairing portable life sup- port system (PLSS), and reviewing plans for second EVA, astronauts left LM at 142:15 GET (7:49 am EDT Aug. 1). LRV was powered up, circuit breakers were cycled, and L8v front steering was found to be completely operational. EVA-2 traverse included stops at Spur Crater, Dune Crater, Hadley Plains, and area between Spur and Window craters. Numerous samples and photos were obtained and TV transmission was good. Crew completed heat flow experiment initiated during EVA-1, collected core sample, and deployed U.S. flag. After stowing sample container and film in LM, astronauts reentered LM at 149:27 GET, after 7 hrs 12 min on surface during EVA-2.
Third EVA began at 163:18 GET (4:52 am EDT Aug. 2), 1 hr 45 min later than planned because of cumulative changes in surface activities timeline. Late start and requirement to protect nominal liftoff time required shortening EvA. Alternate EVA. plan was devised with traverse west from LM to Hadley Rille. Astronauts traveled to Scarp Crater, "The Terrace" near Rim Crater, and Rim Crater, collecting samples and photographing lunar surface features. Scott tripped over a rock and fell, but experienced no difficulty in getting up. Astronauts retrieved drill-core-stem sections and samples near ALSEP, returned to LM, off-loaded LRV and stationed it for TV coverage of LM liftoff, and reentered LM at 168:08 GET, after 4 hrs 50 min-bringing total EVA time to 18 hrs 35 min.
While LM was on moon Worden, orbiting moon in Endeavor, completed lunar and astronomic photography and prepared for rendezvous. His observations included discovery of fields of cinder cones made by volcanic eruptions, delineation of landslide or rock glacier on north-west rim of crater on lunar farside, interpretation of ray-excluded zone around crater Proculus as result of fault system, and discovery of layers on interior walls of several craters, suggesting volcanic collapse craters of calderas in maria.
Scott and Irwin depressurized LM, discarded excess equipment, re-pressurized LM, and lifted off lunar surface with 77 kg (170 lbs) of lunar samples at 171:34 GET (1:11 pm EDT Aug. 2) -66 hrs 55 min after landing on moon. Liftoff, accompanied by USAF anthem "Off We Go Into The Wild Blue Yonder" taped and broadcast by astronauts from LM, was photographed in color by camera on LRV left on moon and was seen by millions of TV viewers. Spacecraft docked successfully at 173:36 GET, as TV viewers watched. Scott and Irwin transferred from LM to CSM with samples, equipment, and film. CSM-LM separation and LM jettison were delayed one revolution to verify that CSM and LM hatches were completely sealed. LM ascent stage was jettisoned and intentionally crashed onto lunar surface at 26° 22' north latitude and 15' east longitude at 181:30 GET, 93 km (59 mi) west of Apollo 15 ALSEP site. Impact was recorded by Apollo 12, Apollo 14, and Apollo 15 seismometers.
Orbit-shaping maneuver was performed during 73rd lunar revolution in preparation for subsatellite launch. Scientific subsatellite was launched at 222:39 GET (4:13 pm EDT Aug. 4) into lunar orbit with 141.3-km (87.8-mi) apolune and 102.0-km (63.4-mi) perilune. Hexagonal, 36-kg (80-1b) satellite 79 cm (31 in) long and 36 cm (14 in) in diameter carried three experiments and was housed in SIM bay with seven other new experiments. Satellite extended three 1i/2-m (5-ft) booms, one with magnetometer to measure interplanetary and earth magnetic fields near moon and two for stabilization. Satellite also carried charged-particle sensors and equipment to detect variations in lunar gravity caused by mascons. Transearth injection maneuver at 223:49 GET put GSM on trajectory for home after 85 hrs 18 min (74 revolutions) in lunar orbit.
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