Apollo XV

Endeavour & Falcon



David R. Scott - CDR
Alfred M. Worden - CMP

James B. Irwin - LMP

Photo Courtesy of JL Pickering

Apollo 15 CSM



Al Worden's deep space EVA
196,000 miles from Earth

Deep Space EVA distance
from Earth record for
microgravity "space walk"
still holds since accomplished
in 1971.

Photo Courtesy of JL Pickering



The mission patch for Apollo 15 was basically designed by the Italian dress designer, Emilio Pucci. We had as a crew evaluated some 540 different designs for our crew patch. They appeared either too mechanical or to have nothing to do with the flight, so finally, through a mutual friend, we asked Pucci if he would help us with the design. Now, Pucci, as I best recall, was an aeronautical engineer and had a good feeling for flight. With his artistic nature, we felt that he would be very helpful in the patch design. He did send us a design which was basically the same as the patch we eventually used, however the colors were in the normal Pucci blues, purples, and greens. We took his design, changed it from a square to a circular patch, made it red, white and blue, and put a lunar background behind the three stylized birds that were the major Pucci contribution. The symbology is of three stylized birds flying over the lunar surface, each indicating one of us who were on the flight. The lunar surface behind the patch shows the landing site (next to Hadley Rille at the foot of the Appenine Mountains) and directly behind the stylized birds is a crater formation that spells "15" in Roman numerals. You can also see from the stylized birds that they fly in formation with one on top and two closer to the lunar surface, indicating those who actually landed.

Lift Off: Saturn V July 26, 1971 9:34 a.m. EDT KSC, Florida Complex 39
On-orbit Dry Mass: 30371 kg
Lunar Landing: July 30, 1971 6:16 p.m. EDT Hadley Apennine
Lunar Lift Off:
Aug. 2, 1971 1:11 p.m. EDT
Splashdown: Aug. 7, 1971 4:45 p.m. EDT Pacific Ocean
Duration: 12 days, 7 hours, 12 minutes


Apollo 15 was the fourth mission in which humans walked on the lunar surface and returned to Earth. On 30 July 1971 two astronauts (Apollo 15 Commander David R. Scott and LM pilot James B. Irwin) landed in the Hadley Rille/Apennines region of the Moon in the Lunar Module (LM) while the Command and Service Module (CSM) (with CM pilot Alfred M. Worden) continued in lunar orbit. During their stay on the Moon, the astronauts set up scientific experiments, took photographs, and collected lunar samples. The LM took off from the Moon on 2 August and the astronauts returned to Earth on 7 August.

Mission Profile

Apollo 15 launched on 26 July 1971 at 13:34:00 UT (9:34:00 a.m. EDT) on Saturn V SA-510 from Pad 39A at Kennedy Space Center. The spacecraft was inserted into Earth orbit at 13:45:44 UT and translunar injection took place at 16:30:03 UT. The CSM separated from the S-IVB stage at 16:56:24 UT and docked with the LM at 17:07:49 UT. The S-IVB stage was released and burns at 19:22 UT and 23:34 UT sent the stage into a lunar impact trajectory. (It impacted the lunar surface on 29 July at 20:58:42.9 UT at 1.51 S, 11.81 W with a velocity of 2.58 km/s at a 62 degree angle from the horizontal.) A short was discovered in the service propulsion system and contingency procedures were developed for using the engine. A mid-course correction was performed on 27 July at 18:14:22 UT and another on 29 July at 15:05:15. During cruise it was discovered that the LM range/range-rate exterior glass cover had broken and a small water leak had developed in the CM requiring repair and clean-up. The SIM door was jettisoned at 15:40 UT and lunar orbit insertion took place at 20:05:47 UT. The descent orbit maneuver was executed at 00:13:49 UT on 30 July.

Scott and Irwin entered the LM and the LM-CSM undocking maneuver was initiated at 17:48 UT but undocking did not take place. Worden found a loose umbilical plug and reconnected it, allowing the LM to separate from the CSM at 18:13:30 UT. The LM fired its descent engine at 22:04:09 UT and landed at 22:16:29 UT on 30 July 1971 in the Mare Imbrium region at the foot of the Apennine mountain range at 26.1 N, 3.6 E. Scott and Irwin made three moonwalk EVAs totaling 18 hours, 35 minutes. During this time they covered 27.9 km, collected 76.8 kg of rock and soil samples, took photographs, and set up the ALSEP and performed other scientific experiments. This was the first mission which employed the Lunar Roving Vehicle which was used to explore regions within 5 km of the LM landing site. After the final EVA Scott performed a televised demonstration of a hammer and feather falling at the same rate in the lunar vacuum. The CSM remained in a slightly elliptical orbit from which Worden performed scientific experiments.

The LM lifted off from the Moon at 17:11:22 UT on 2 August after 66 hours, 55 minutes on the lunar surface. After the LM docked with the CSM at 19:09:47 UT the lunar samples and other equipment were transferred from the LM. The LM was jettisoned at 01:04:14 UT on 3 August, after a one orbit delay to ensure LM and CSM hatches were completely sealed. The LM impacted the Moon on 3 August 03:03:37.0 UT at 26.36 N, 0.25 E, 93 km west of the Apollo 15 ALSEP site, with an estimated impact velocity of 1.7 km/s at an angle of ~3.2 degrees from horizontal. Experiments were performed from orbit over the next day. After Apollo 15 underwent an orbit-shaping maneuver the scientific subsatellite was spring-launched from the SM SIM bay at 20:13:19 UT on 4 August into a 102.0 x 141.3 km lunar orbit. Transearth injection began on the next orbit with a 2 minute, 21 second main engine burn at 21:22:45 UT. On 5 August, Worden carried out the first deep space EVA when he exited the CM and made three trips to the SIM bay at the rear of the SM to retrieve film cannisters and check the equipment. Total EVA time was 38 minutes, 12 seconds. The CM separated from the SM at 20:18:00 UT on 7 August. During descent, one of the three main parachutes failed to open fully, resulting in a descent velocity of 35 km/hr (21.8 mph), 4.5 km/hr (2.8 mph) faster than planned. Apollo 15 splashed down in the Pacific Ocean on 7 August 1971 at 20:45:53 UT (4:45:53 p.m. EDT) after a mission elapsed time of 295 hrs, 11 mins, 53 secs. The splashdown point was 26 deg 7 min N, 158 deg, 8 min W, 330 miles north of Honolulu, Hawaii and 9.8 km (6.1 mi) from the recovery ship USS Okinawa.

Performance of the spacecraft, the first of the Apollo J-series missions, was excellent for most aspects of the mission. The primary mission goals of exploration of the Hadley-Appenine region, deployment of the ALSEP and other scientific experiments, collection of lunar samples, surface photography, and photography and other scientific experiments from orbit, and engineering evaluation of new Apollo equipment, particularly the rover, were achieved. Scott, 39, was an Air Force Colonel on his third spaceflight (he'd flown previously on Gemini 8 and Apollo 9), Worden, 39, was an Air Force Major on his first spaceflight, and Irwin, 41, was an Air Force Lt. Colonel also on his first spaceflight. The backup crew for this mission was Richard Gordon, Vance Brand, and Harrison Schmitt. The Apollo 15 command module "Endeavor" is on display at the USAF Museum at Wright-Patterson Air Force Base, Dayton, Ohio.


Did you know that all three of the Apollo 15 space crew are alumni of the University of Michigan? The crew flew to the moon from July 26-August 7, 1971 with astronauts:
  • David Scott, '49-'50
  • Alfred Worden, MSE'63
  • James Irwin, MSE'57

Apollo 15 was the first expedition with a lunar rover vehicle (used by Scott and Irwin who went to the surface of the moon) and the first flight in which all three astronauts were from the same university. They carried three U-M items: a miniature U-M flag, a miniature of the U-M Department of Aerospace Engineering seal and a charter of the U-M Alumni Club of the Moon, which was left on the moon.




Apollo 15 Lunar Module / ALSEP

NSSDC ID: 1971-063C


The Apollo 15 lunar module (LM) "Falcon" was the fourth crewed vehicle to land on the Moon. It carried two astronauts, Commander David R. Scott and LM pilot James B. Irwin, the seventh and eighth men to walk on the Moon. The LM also carried a Lunar Roving Vehicle (LRV), an Apollo Lunar Surface Experiments Package (ALSEP) that contained scientific experiments to be deployed and left on the lunar surface, and other scientific and sample collection apparatus. The experiments performed on the Moon, in addition to the ALSEP suite, were geologic sample collection, surface photography, soil mechanics investigations to study physical properties of the lunar regolith, and the solar wind composition experiment which collected samples of solar wind particles for return to Earth.

Mission Profile

The LM separated from the Command/Service Module (CSM) at 18:13:30 UT and landed at 22:16:29 UT (6:16:29 p.m. EDT) on 30 July 1971 in the Mare Imbrium region at the foot of the Apennine mountain range at 26.1322 N latitude, 3.6339 E longitude (IAU Mean Earth Polar Axis coordinate system). Scott and Irwin made three moonwalk extra-vehicular activities (EVAs) totaling 18 hours, 35 minutes. During this time they covered 27.9 km and collected 77.31 kg of rock and soil samples. The LRV was used to explore regions within 5 km of the LM landing site. This was the first time a vehicle of this type had been used, and its performance on the lunar terrain was very successful. Two hours after landing the cabin was depressurized and Scott performed a standup EVA for 33 minutes, describing and photographing the surrounding terrain from the LM upper hatch. The first moonwalk EVA was on 31 July from 13:13:10 UT to 19:45:59 UT, during which time the LRV was unloaded, deployed, and driven. Photographs of the lunar surface were taken and geologic samples were collected from the LM site and during the three geological traverses. The traverse on the first EVA covered 10.3 km to the edge of Hadley Rille to Elbow Crater and near St. George Crater and back to the LM, where a core sample was taken from three meters below the surface. The ALSEP was deployed at the end of the traverse. On the second EVA, on 1 August from 11:48:48 UT to 19:01:02 UT, the LRV was driven on a 12.5 km traverse southeast along the base of the Appenine Mountains near Index, Arbeit, Crescent, Dune, and Spur craters and back to the ALSEP site. On the third EVA on 2 August from 08:52:14 UT to 13:42:04 UT the LRV was driven a total of 5.1 km west to Scarp Crater and northwest along the edge of Hadley Rille and back east across the mare. After the final EVA Scott performed a televised demonstration of a hammer and feather falling at the same rate in the lunar vacuum. The astronauts also left a plaque and small figure on the surface in memory of all fourteen American and Soviet space explorers who had died during the two nation's space programs. The LM lifted off the Moon on 2 August at 17:11:22 UT after 66 hours, 55 minutes on the lunar surface. After docking with the CSM (piloted by Alfred M. Worden) at 19:09:47 UT the LM was jettisoned on 3 August at 01:04:14 UT and impacted on the Moon 2 hours later (03:03:37.0 UT) at 26.36 N, 0.25 E.

Lunar Module Spacecraft and Subsystems

The lunar module was a two-stage vehicle designed for space operations near and on the Moon. The spacecraft mass of 16,434 kg was the mass of the LM including astronauts, expendables, and approximately 12,000 kg of propellants. The fully fueled mass of the ascent stage was about 4971 kg and the descent stage 11,463 kg. The ascent and descent stages of the LM operated as a unit until staging, when the ascent stage functioned as a single spacecraft for rendezvous and docking with the command and service module (CSM). The descent stage comprised the lower part of the spacecraft and was an octagonal prism 4.2 meters across and 1.7 m thick. Four landing legs with round footpads were mounted on the sides of the descent stage and held the bottom of the stage 1.5 m above the surface. The distance between the ends of the footpads on opposite landing legs was 9.4 m. One of the legs had a small astronaut egress platform and ladder. A one meter long conical descent engine skirt protruded from the bottom of the stage. The descent stage contained the landing rocket, two tanks of aerozine 50 fuel, two tanks of nitrogen tetroxide oxidizer, water, oxygen and helium tanks and storage space for the lunar equipment and experiments, and in the case of Apollo 15, 16, and 17, the lunar rover. The descent stage served as a platform for launching the ascent stage and was left behind on the Moon.

The ascent stage was an irregularly shaped unit approximately 2.8 m high and 4.0 by 4.3 meters in width mounted on top of the descent stage. The ascent stage housed the astronauts in a pressurized crew compartment with a volume of 6.65 cubic meters. There was an ingress-egress hatch in one side and a docking hatch for connecting to the CSM on top. Also mounted along the top were a parabolic rendezvous radar antenna, a steerable parabolic S-band antenna, and 2 in-flight VHF antennas. Two triangular windows were above and to either side of the egress hatch and four thrust chamber assemblies were mounted around the sides. At the base of the assembly was the ascent engine. The stage also contained an aerozine 50 fuel and an oxidizer tank, and helium, liquid oxygen, gaseous oxygen, and reaction control fuel tanks. There were no seats in the LM. A control console was mounted in the front of the crew compartment above the ingress-egress hatch and between the windows and two more control panels mounted on the side walls. The ascent stage was launched from the Moon at the end of lunar surface operations and returned the astronauts to the CSM.

The descent engine was a deep-throttling ablative rocket with a maximum thrust of about 45,000 N mounted on a gimbal ring in the center of the descent stage. The ascent engine was a fixed, constant-thrust rocket with a thrust of about 15,000 N. Maneuvering was achieved via the reaction control system, which consisted of the four thrust modules, each one composed of four 450 N thrust chambers and nozzles pointing in different directions. Telemetry, TV, voice, and range communications with Earth were all via the S-band antenna. VHF was used for communications between the astronauts and the LM, and the LM and orbiting CSM. There were redundant tranceivers and equipment for both S-band and VHF. An environmental control system recycled oxygen and maintained temperature in the electronics and cabin. Power was provided by 6 silver-zinc batteries. Guidance and navigation control were provided by a radar ranging system, an inertial measurement unit consisting of gyroscopes and accelerometers, and the Apollo guidance computer.

Apollo Lunar Surface Experiments Package (ALSEP)

The Apollo Lunar Surface Experiments Package (ALSEP) consisted of a set of scientific instruments emplaced at the landing site by the astronauts. The instruments were arrayed around a central station which supplied power to run the instruments and communications so data collected by the experiments could be relayed to Earth. The central station was a 25 kg box with a stowed volume of 34,800 cubic cm. Thermal control was achieved by passive elements (insulation, reflectors, thermal coatings) as well as power dissipation resistors and heaters. Communications with Earth were achieved through a 58 cm long, 3.8 cm diameter modified axial-helical antenna mounted on top of the central station and pointed towards Earth by the astronauts. Transmitters, receivers, data processors and multiplexers were housed within the central station. Data collected from the instruments were converted into a telemetry format and transmitted to Earth. The ALSEP system and instruments were controlled by commands from Earth. The uplink frequency for all Apollo mission ALSEP's was 2119 MHz, the downlink frequency for the Apollo 15 ALSEP was 2278.0 MHz.

Radioisotope Thermoelectric Generator (RTG)

The SNAP-27 model RTG produced the power to run the ALSEP operations. The generator consisted of a 46 cm high central cylinder and eight radiating rectangular fins with a total tip-to-tip diameter of 40 cm. The central cylinder had a thinner concentric inner cylinder inside, and the two cylinders were attached along their surfaces by 442 spring-loaded lead-telluride thermoelectric couples mounted radially along the length of the cylinders. The generator assembly had a total mass of 17 kg. The power source was an approximately 4 kg fuel capsule in the shape of a long rod which contained plutonium-238 and was placed in the inner cylinder of the RTG by the astronauts on deployment. Plutonium-238 decays with a half-life of 89.6 years and produces heat. This heat would conduct from the inner cylinder to the outer via the thermocouples which would convert the heat directly to electrical power. Excess heat on the outer cylinder would be radiated to space by the fins. The RTG produced approximately 70 W DC at 16 V. (63.5 W after one year.) The electricity was routed through a cable to a power conditioning unit and a power distribution unit in the central station to supply the correct voltage and power to each instrument.

ALSEP Scientific Instruments

All ALSEP instruments were deployed on the surface by the astronauts and attached to the central station by cables. The Apollo 15 ALSEP instruments consisted of: (1) a passive seismometer, designed to measure seismic activity and physical properties of the lunar crust and interior; (2) a lunar surface magnetometer (LSM), designed to measure the magnetic field at the lunar surface; (3) a solar wind spectrometer, which measured the fluxes and spectra of the electrons and protons that emanate from the Sun and reach the lunar surface; (4) a suprathermal ion detector, designed to measure the flux, composition, energy, and velocity of low-energy positive ions; (5) a cold cathode ion gauge, designed to measure the atmosphere and any variations with time or solar activity such atmosphere may have; (6) a lunar dust detector, to measure dust accumulation, radiation damage to solar cells, and reflected infrared energy and temperatures; and (7) a heat flow experiment, designed to measure the rate of heat loss from the lunar interior and the thermal properties of lunar material. The central station, located at 26.1341 N latitude, 3.6298 E longitude, was turned on at 18:37 UT on 31 July 1971 and shut down along with the other ALSEP stations on 30 September 1977.

Alternate Names

  • Apollo 15C
  • Apollo 15 LM/ALSEP
  • LEM 15
  • Falcon
  • LM-10
  • Rover 15
  • 05366

Facts in Brief

Launch Date: 1971-07-26
Launch Vehicle: Saturn 5
Launch Site: Cape Canaveral, United States
Mass: 16434.0 kg

Funding Agencies

  • NASA-Office of Space Science (United States)
  • NASA-Office of Manned Space Flight (United States)


  • Earth Science
  • Human Crew
  • Planetary Science
  • Space Physics

Additional Information

Experiments on Apollo 15 Lunar Module / ALSEP

Data collections from Apollo 15 Lunar Module / ALSEP


Questions or comments about this spacecraft can be directed to: Dr. David R. Williams.



Name Role Original Affiliation  
Dr. John B. Hanley Program Scientist NASA Headquarters  
Mr. Wilbert F. Eichelman Project Manager NASA Johnson Space Center  
Mr. Floyd I. Roberson Program Manager NASA Headquarters  

Selected References

Apollo 15 preliminary science report, NASA, SP-289, Wash., D.C., 1972.

Davies, M. E., and T. R. Colvin, Lunar coordinates in the regions of the Apollo landers, J. Geophys. Res., 105, No. E8, 20277-20280, Aug. 2000.

[Apollo LM diagram]
Diagram of the Apollo LM courtesy of NASA History Office.

Apollo 15 Command Module record
Apollo 15 Subsatellite record
The Apollo Lunar Roving Vehicle
Apollo 15 Home Page
Apollo landing sites and ALSEP and LRRR locations - and information on the modified DMA/603 control network

Apollo Home Page
Lunar Science Home Page
Moon Home Page


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