Luna 20
A robot's sample of the bright, ancient highlands of the Moon.
Key facts
- Agency
- Soviet Union
- Type of mission
- Robotic sample return
- Target
- The Moon: highlands near Apollonius crater
- Launched
- 14 February 1972
- Samples returned
- 55 g of lunar soil
- Status
- Completed 1972
Luna 20 was the second successful Soviet sample return, and the first to collect from the lunar highlands. It landed on 21 February 1972 in rugged country near the crater Apollonius, between Mare Fecunditatis and Mare Crisium, only about 120 kilometres from where Luna 16 had touched down.
The ground was hard, and the drill stalled several times, so it collected only 55 grams before the soil was sealed into the return capsule. The capsule landed in Kazakhstan on 25 February 1972, in a snowstorm, and was found on an island in a river.
What the soil showed
Highland soil looks quite different from mare soil. Luna 20's grains were pale, rich in plagioclase feldspar and in rocks called anorthosites, which are made almost entirely of that mineral. Highland rocks are older than the mare lavas, and they had been broken and remelted over and over by impacts.
The sample supported an idea that came from the Apollo 11 soil: that the young Moon was covered by an ocean of molten rock, and that light feldspar crystals floated to the top of it to form the first crust.
Why it matters to meteorites
Most lunar meteorites are highland breccias, because the highlands cover most of the Moon. Luna 20 and Apollo 16 are the reference points for recognising them.
Key dates
| Date | What happened |
|---|---|
| 14 February 1972 | Luna 20 launched. |
| 21 February 1972 | Landed in the highlands near Apollonius crater. |
| 25 February 1972 | The capsule returned to Kazakhstan with 55 g of highland soil. |
See where this mission fits among all the others in the mission timeline.
Did you know?
Luna 20 landed only about 120 km from Luna 16, so the two samples show how sharply soil changes between a lunar sea and the highlands.
Some Luna 20 soil was exchanged with NASA for Apollo samples, so scientists in both countries could study both sets.