Apollo 15
In September 1970, NASA made a decision that would transform the Apollo program from a series of short visits into an era of extended lunar exploration. The agency cancelled three planned landing missions to cut costs, leaving only five landings remaining. This cancellation forced a shift in strategy for the upcoming flights. Apollo 15 became the first of these new extended missions, known as J missions. These missions required longer stays on the Moon and a heavier focus on scientific research compared to earlier attempts. The original plan had designated Apollo 15 to land in Censorinus crater, but budget cuts changed everything. The landing site moved to Hadley Rille, a deep channel on the edge of Mare Imbrium near the Apennine mountains. This location was originally intended for Apollo 19. The Site Selection Committee narrowed their choices to two sites: Hadley Rille or Marius crater. David Scott, the commander, felt Hadley offered more variety and beauty. He believed that when things looked good, they were likely good. The proximity of the Apennine mountains required a steeper landing approach trajectory of 26 degrees. Earlier missions used a 15-degree angle. NASA lacked high-resolution images of this rough terrain before making the choice.
David Scott was born in 1932 in San Antonio, Texas, and graduated from the United States Military Academy in 1954. James Irwin came from Pittsburgh and attended the United States Naval Academy, graduating in 1951. Alfred Worden was born in Jackson, Michigan, and earned two master's degrees in engineering from the University of Michigan in 1963. All three men had attended the University of Michigan, which was the first university to offer an aeronautical engineering program. They received extensive geological training to prepare for their scientific duties. Geologist Lee Silver worked with the crew to teach them field techniques. Silver took the astronauts on monthly field trips throughout their twenty months of training. These trips started as standard lessons but became increasingly realistic as launch approached. Crews wore mock-ups of backpacks while hiking near the Rio Grande Gorge. They communicated using walkie-talkies to a CAPCOM in a tent who relied on their descriptions to interpret findings. Farouk El-Baz trained Worden to describe lunar features from orbit. The demands of this rigorous training strained marriages. Both Worden and Irwin sought advice from Scott fearing divorce might endanger their places on the mission. The Wordens divorced before the flight began.
The Saturn V rocket designated SA-510 launched Apollo 15 on the 26th of July 1971. This was the tenth flight-ready model of the rocket. Changes were made to accommodate the heavier payload. The propellant reserves were reduced and retrorockets on the S-IC stage decreased from eight to four. The Lunar Module LM-10 carried two falcon feathers to honor the crew's Air Force service. A new space suit called the A7LB featured connectors in triangular pairs instead of parallel rows. An entry zipper ran diagonally from right shoulder to left hip. This design allowed astronauts to bend completely over and sit on the rover. The Lunar Roving Vehicle weighed 460 pounds unloaded but reached 1500 pounds with two astronauts. Each wheel had an independent electric motor producing 200 watts. The vehicle could travel up to 8 miles per hour. Boeing received a contract for three rovers costing $40 million total. Cost overruns gained media attention during a time of public weariness with the space program. The rover could fold into a space measuring 5 feet by 20 inches. It bore a plaque reading Man's First Wheels on the Moon.
Falcon landed at Hadley Rille on the 30th of July 1971, at 22:16:29 GMT. Scott and Irwin spent 18 hours outside the lander across four extravehicular activities. They collected approximately 170 pounds of lunar samples. During the second EVA on August 1, they visited Spur crater and found a sample dubbed Genesis Rock. This rock is believed to be part of the early lunar crust. In the third EVA, Scott dropped a hammer and a feather simultaneously. The objects hit the ground at the same time because there was no air resistance. Joe Allen suggested this experiment as a memorable science demonstration. The crew also left a small aluminum statuette called Fallen Astronaut near the rover. A plaque bearing names of 14 deceased astronauts and cosmonauts accompanied it. Scott placed a Bible on the control panel before entering the lander for the last time. The first EVA lasted 6 hours and 32 minutes while the second ran 7 hours and 12 minutes. The final moonwalk took 4 hours, 49 minutes, and 50 seconds.
Alfred Worden orbited the Moon in the Command Module Endeavour while his crewmates explored below. He operated instruments in the Scientific Instrument Module bay including a gamma-ray spectrometer and laser altimeter. A panoramic camera derived from spy technology captured detailed images. An alpha particle spectrometer detected evidence of lunar volcanism. The mass spectrometer boom proved troublesome as it did not always retract fully. Worden took many photographs through the command module windows at regular intervals. His observations informed decisions to send Apollo 17 to Taurus-Littrow. He greeted each resumption of contact with Hello Earth Greetings from Endeavour spoken in different languages. Results showed greater fluorescent X-ray flux than anticipated. Data indicated lunar highlands were richer in aluminum than mare regions. The CSM orbit drifted due to the rotation of the Moon requiring a plane change burn. Worden executed this 18-second burn with the SPS engine to align orbits before docking.
On the 4th of August 1971, Worden performed the first spacewalk in deep space. This EVA occurred approximately 171,000 nautical miles from Earth. It remains one of only three such EVAs performed during the Apollo program. Irwin assisted by remaining at the command module hatch while Worden retrieved film cassettes from the SIM bay. The distance made this operation unique compared to previous moonwalks. Later that day, the crew set a record for the longest Apollo flight to that point. The mission lasted 12 days, 7 hours, 11 minutes, and 53 seconds total. Upon return, the service module was jettisoned before reentry. One parachute failed after deploying but two sufficed for a safe landing. The capsule splashed down in the North Pacific Ocean on August 7.
The careers of all three astronauts were tarnished by an unauthorized deal to carry postal covers to the Moon. Walter Eiermann served as intermediary between the crew and West German stamp dealer Hermann Sieger. Scott carried about 400 covers onto the spacecraft which remained inside Falcon during surface activities. No permission had been received from Deke Slayton to transport these items. In late 1971, 100 covers went on sale for approximately $1,500 each. After receiving agreed payments, the astronauts returned them without accepting compensation. Slayton learned of the unauthorized covers in April 1972 and removed the trio as backup crew for Apollo 17. The matter became public in June 1972 leading to a reprimand for poor judgment. None of the astronauts flew in space again. Worden filed suit and the covers were returned in 1983. During congressional hearings, Bulova timepieces taken by Scott also faced scrutiny. A prototype Chronograph Model #88510/01 sold for $1.625 million in 2015.
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Common questions
When did Apollo 15 launch and land on the Moon?
The Saturn V rocket designated SA-510 launched Apollo 15 on the 26th of July 1971. The Lunar Module Falcon landed at Hadley Rille on the 30th of July 1971.
Who were the three astronauts assigned to the Apollo 15 mission?
David Scott served as commander, James Irwin was the lunar module pilot, and Alfred Worden acted as command module pilot. All three men had attended the University of Michigan which was the first university to offer an aeronautical engineering program.
What scientific equipment did Alfred Worden operate in orbit around the Moon?
Worden operated instruments in the Scientific Instrument Module bay including a gamma-ray spectrometer and laser altimeter. He also used a panoramic camera derived from spy technology and an alpha particle spectrometer to detect evidence of lunar volcanism.
Why did NASA change the landing site for Apollo 15 from Censorinus crater to Hadley Rille?
Budget cuts forced a shift in strategy that moved the landing site to Hadley Rille near the Apennine mountains. Commander David Scott felt Hadley offered more variety and beauty compared to other options like Marius crater.
How long did each extravehicular activity last during the Apollo 15 surface operations?
The first EVA lasted 6 hours and 32 minutes while the second ran 7 hours and 12 minutes. The final moonwalk took 4 hours, 49 minutes, and 50 seconds.