Apollo 11
The first Moon rocks, collected by the first people to walk on another world.
Key facts
- Agency
- NASA (United States)
- Type of mission
- Crewed landing and sample return
- Target
- The Moon: Mare Tranquillitatis
- Launched
- 16 July 1969
- Samples returned
- 21.5 kg of rock and soil
- Status
- Completed 1969
On 20 July 1969 Neil Armstrong and Buzz Aldrin landed the lunar module Eagle on Mare Tranquillitatis, the Sea of Tranquillity, while Michael Collins circled overhead. In about two and a half hours outside, they filled boxes with 21.5 kilograms of rock and soil, set up experiments and took core tubes of the ground.
What the rocks showed
The rocks were basalts, dark volcanic lavas like those of Iceland or Hawaii but unusually rich in titanium and completely dry: they contain no water-bearing minerals at all. Dating showed they had erupted about 3.6 to 3.9 billion years ago, older than almost any rock on Earth's surface.
The soil held something unexpected: small white chips of anorthosite, a rock made almost entirely of plagioclase feldspar, thrown in from the distant highlands. Scientists reasoned that the young Moon had melted into a global ocean of magma, and that feldspar crystals had floated to its surface to make the first crust. That magma ocean idea is now central to how planets are thought to form.
New minerals
Apollo 11 rocks contained three minerals new to science: armalcolite, named after the three astronauts, tranquillityite and pyroxferroite. Armalcolite and tranquillityite have since been found on Earth.
Why it matters to meteorites
The Apollo collection is the yardstick for lunar meteorites. In 1982 a small stone from Antarctica, Allan Hills 81005, was recognised as lunar because it matched Apollo highland samples so closely.
Key dates
| Date | What happened |
|---|---|
| 16 July 1969 | Apollo 11 launched on a Saturn V rocket. |
| 20 July 1969 | Armstrong and Aldrin landed in the Sea of Tranquillity and walked on the Moon. |
| 24 July 1969 | The crew splashed down in the Pacific Ocean with 21.5 kg of samples. |
See where this mission fits among all the others in the mission timeline.
Did you know?
The astronauts left behind a laser reflector that is still used to measure the distance to the Moon to within a few centimetres.
Armalcolite takes its name from the first letters of Armstrong, Aldrin and Collins.