KLEOS I

Mission 01 · The Moon · July 1969

Apollo 11: Eagle

“Houston, Tranquility Base here. The Eagle has landed.” A two-stage spacecraft with two very different jobs: one stage landed the astronauts, and the other carried them back to orbit.

Start Chapter 1 →Explore in 3D
20 Jul 1969Lunar landing date
20:17:40 UTCTouchdown time
0.67416° N, 23.47314° ELanding site, Sea of Tranquility

The Eagle's bottom half says:

I'm the descent stage of Apollo 11's lander, Eagle. I look like an eight-sided box, about 4.2 meters (14 feet) across, on four folding legs. I landed safely on the Moon on July 20, 1969 at 20:17:40 UTC. (13:32 UTC was the Saturn V launch time on July 16.) My legs have crushable honeycomb shock absorbers, so landing feels like a gentle squish.

My engine could be turned up and down, with up to 10,125 pounds of push. On July 20, 1969, Neil Armstrong and Buzz Aldrin rode me down to the Sea of Tranquility. Long feelers on my footpads told the commander the moment we touched the ground.

When it was time to go home, the top half, the ascent stage, lit its own engine and blasted off after 21 hours and 36 minutes on the Moon. I was its launch pad, and my job was to stay.

A plaque is bolted to one of my struts, right behind the ladder. The astronauts read it aloud: "Here men from the planet Earth first set foot on the Moon July 1969, A.D. We came in peace for all mankind."

I'm not alone. Six of us, one from each Moon landing, are parked at six different places. Cameras on a NASA orbiter can still spot us from above.

Interactive

Explore the Lunar Module in 3D

Rotate and inspect NASA's digital Apollo Lunar Module. Drag to rotate, scroll or pinch to zoom. Find the four landing legs, the ladder and the descent engine bell at the bottom.

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Interactive 3D model: Apollo Lunar Module. Credit: NASA / Michael D. Carbajal. Source: NASA 3D Resources ↗

Seven chapters

Eagle's journey, one step at a time

Choose a stage of the mission to explore its engineering, people and science. Each card opens a dedicated story chapter.

0 of 7 read
✓01Meet the Descent StageStructure, landing legs and the job I was built to doChapter 1✓02The Landing20 July 1969, the Sea of Tranquility and exact coordinatesChapter 2✓03How Landing WorkedDescent engine, propellants, probes and shock absorbersChapter 3✓04Meet the Ascent StageCrew cabin, navigation, communications and return engineChapter 4✓05Liftoff and JettisonLeaving the Moon, docking with Columbia and separationChapter 5✓06The Plaque and Our LegacyThe message left behind and hardware still on the MoonChapter 6✓07EASEP: Science on the MoonSeismometer, dust detector, solar power and laser reflectorChapter 7

The Moon's first science station says:

I'm EASEP, the Early Apollo Scientific Experiments Package. Armstrong and Aldrin set me up about 17 meters south of Eagle. I'm a seismometer that feels moonquakes, a dust detector that checks how dust builds up on solar cells, and two solar panels that power me.

Because I run on sunlight, I could only work during the Moon's daytime. Mission control switched me on from Earth on July 21, 1969, while the astronauts were still outside. It got hotter than planned, 30 degrees Celsius over my limit, but I kept working fine.

On August 3, 1969, just before sunset, my power began to drop as expected, so NASA turned me off. I woke up for the next lunar day, but on August 27 I stopped answering commands, and my work ended.

About 5 meters away sits my mirror buddy, a laser-ranging retroreflector. It's a special mirror that bounces laser light straight back, and it needs no electricity at all.

Mission records

Armstrong stepped onto the lunar surface at 02:56:15 UTC on July 21. Aldrin followed about 19 minutes later. The astronauts collected 21.55 kilograms of lunar samples and deployed the EASEP about 17 metres south of the Lunar Module. A laser-ranging retroreflector was placed nearby and can still be used for lunar distance measurements.

This NASA image streams from NASAConnect to the internet to see it, or view it on NASA.gov ↗
Apollo 11 photograph, frame AS11-44-6642 · Credit: NASA. More in NASA's Apollo 11 archive ↗

By the numbers

Apollo 11 in figures

  • 6Apollo descent stages still on the Moon
  • 10,125pounds of push from the descent engine
  • 21.55 kgof lunar samples collected
  • 21 h 36 mon the lunar surface before liftoff

Did you know?

Why did astronauts crash the top halves on purpose?

The astronauts left seismometers (Moon-quake detectors) on the surface. Crashing the empty ascent stages gave those instruments a known thump to record. Apollo 11's top half was dropped into lunar orbit instead. NASA's records say its fate isn't known, but it is assumed to have crashed within a few months. Apollo 13 never landed.

Which lander became a lifeboat?

Apollo 13's lander, Aquarius. After an oxygen tank burst in the main spacecraft, the crew moved into it. It was built to support two astronauts for about 45 hours, and it kept three alive for about 90 hours.

Next mission

Surveyor 3: the bouncing scout

Before Eagle, a robot had to prove the Moon would hold. Meet the lander that bounced twice.

Continue →