On the 26th July 1971, the Apollo 15 mission launched from Cape Canaveral, Florida, with David Scott (commander), Alfred Worden (command module pilot) and James Irwin (lunar module pilot) on board. A few days later, the Apollo 15 lunar lander “Falcon”, landed on the edge of the Imbrium Basin in an area known as the “Marsh of Decay”. Scott and Irwin became the seventh and eighth people, respectively, to walk on the moon. The Apollo 15 mission had four main goals:
1. To explore the geology of the landing site and surrounding area.
2. To deploy scientific experiments on the lunar surface.
3. To evaluate the performance of new technology and equipment.
4. To undertake experiments and photograph the lunar surface whilst in lunar orbit.
Despite Apollo 15 being the fourth Apollo mission to land on the Moon’s surface, it was actually a mission of firsts in many ways! Apollo 15 was the first of NASA’s “J” missions designed to stay for longer periods of time on the Moon. Astronauts David Scott and James Irwin spent almost 3 days on the lunar surface, beating the previous record set by Apollo 14 of 33 hours. The Lunar Roving Vehicle (LRV) was also used for the first time enabling the astronauts to drive a total of 17.5 miles across the lunar surface. A camera mounted to the LRV allowed geologists and other scientists back on Earth to see the surface in real-time and assist the astronauts easier. At the time, back in 1971, Apollo 15 set further records for the largest payload in lunar orbit, longest duration spent doing extravehicular activities (EVAs), longest time spent in lunar orbit, longest crewed mission and the first deep space EVA.
Apollo 15 returned a total of 77 kg of rocks back to Earth, including over 350 individual samples ranging from 1g up to 9.5 kg. Two of the most famous samples collected by Apollo 15 are the Genesis Rock and a sample known as Great Scott. The Genesis Rock was an exciting discovery, as it was originally thought to be a piece of the Moon’s original crust. The sample is rock called anorthosite that is made up of a light coloured mineral called feldspar and forms the lunar highlands. However, age dating of the sample revealed the rock to be ~4.1 billion years old which is too young to be part of the original crust, but was still an important discovery and one of the oldest rocks collected! The largest single sample collected by Apollo 15 was a 9.5 kg rock known as Great Scott, named after the mission commander David Scott. This sample is a mare basalt, a volcanic rock erupted onto the lunar surface over 3 billion years ago. Great Scott went on to be one of the most studied rocks within the whole Apollo 15 sample collection.
I nominated Apollo 15 as I was fortunate enough during my PhD to be able to study some of the mare basalts (volcanic rocks) brought back to Earth during this mission (including Great Scott!). Analysing samples like these allows us to understand more about how magma travelled through the Moon’s crust and was erupted onto its surface billions of years ago!
Apollo 15 isn’t as well-known or as famous as some of the other Apollo missions but it certainly made an important contribution to the Apollo program, lunar exploration and to the future of crewed missions. Please show this mission the appreciation it deserves and vote for Apollo 15 in Mission Cup 2021!