Mission MoonSpace Knowledge
Moon • Astronomy • Exploration
The Moon & Space Knowledge Guide
A growing library of practical explainers, lunar science notes, mission history and quick facts for anyone curious about the Moon and humanity's exploration of space.
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Moon
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How far is the Moon from Earth?
A Practical Guide
How long does it take light to reach the Moon?
A Practical Guide
How long is a day on the Moon?
A Practical Guide
Why does the same side of the Moon face Earth?
A Practical Guide
Does the Moon have an atmosphere?
A Practical Guide
How strong is gravity on the Moon?
A Practical Guide
How old is the Moon?
A Practical Guide
How did the Moon form?
A Practical Guide
Why are there craters on the Moon?
A Practical Guide
What are lunar maria?
A Practical Guide
What are lunar highlands?
A Practical Guide
What is the Moon's regolith?
A Practical Guide
Why is lunar dust difficult?
A Practical Guide
Can you hear sound on the Moon?
A Practical Guide
Why does the Moon have phases?
A Practical Guide
What is a new moon?
A Practical Guide
What is a full moon?
A Practical Guide
What is a lunar eclipse?
A Practical Guide
What is a solar eclipse?
A Practical Guide
Why doesn't an eclipse happen every month?
A Practical Guide
What is lunar libration?
A Practical Guide
How fast does the Moon orbit Earth?
A Practical Guide
How fast does the Moon rotate?
A Practical Guide
How big is the Moon?
A Practical Guide
How does the Moon compare with Earth?
A Practical Guide
How cold is the Moon?
A Practical Guide
Why are lunar polar regions interesting?
A Practical Guide
Is there water on the Moon?
A Practical Guide
Why is lunar water important?
A Practical Guide
What is a permanently shadowed region?
A Practical Guide
What is the Moon's south pole?
A Practical Guide
What was Apollo 11?
A Practical Guide
Who was the first person on the Moon?
A Practical Guide
Who was the second person on the Moon?
A Practical Guide
What did Michael Collins do on Apollo 11?
A Practical Guide
How long did Apollo 11 stay on the Moon?
A Practical Guide
How many Apollo missions landed humans on the Moon?
A Practical Guide
How many people have walked on the Moon?
A Practical Guide
When was the last human Moon landing?
A Practical Guide
Who was the last person on the Moon?
A Practical Guide
Why was Apollo 12 important?
A Practical Guide
Why was Apollo 15 important?
A Practical Guide
Why was Apollo 16 important?
A Practical Guide
Why was Apollo 17 important?
A Practical Guide
What was the Lunar Roving Vehicle?
A Practical Guide
What is a lunar sample?
A Practical Guide
Why are Moon rocks valuable to science?
A Practical Guide
What was Apollo 13?
A Practical Guide
What is the Saturn V?
A Practical Guide
How tall was Saturn V?
A Practical Guide
How powerful was Saturn V?
A Practical Guide
What is translunar injection?
A Practical Guide
What is lunar orbit?
A Practical Guide
What is lunar orbit insertion?
A Practical Guide
What is a lunar lander?
A Practical Guide
Why is landing on the Moon difficult?
A Practical Guide
What is a soft landing?
A Practical Guide
What is a lunar rover?
A Practical Guide
What was Lunokhod 1?
A Practical Guide
What is Chang'e in lunar exploration?
A Practical Guide
What is the Artemis program?
A Practical Guide
Why is the Moon a testbed for Mars?
A Practical Guide
How long does a trip to the Moon take?
A Practical Guide
Why do spacecraft take different routes to the Moon?
A Practical Guide
What is a Hohmann transfer?
A Practical Guide
What is an Earth–Moon Lagrange point?
A Practical Guide
What is Gateway?
A Practical Guide
What is a lunar habitat?
A Practical Guide
How do astronauts breathe on the Moon?
A Practical Guide
How do spacesuits work on the Moon?
A Practical Guide
Why are lunar nights a power challenge?
A Practical Guide
What is a lunar solar day?
A Practical Guide
Why are lunar shadows so dark?
A Practical Guide
Why does the Moon look bright?
A Practical Guide
What is Earthshine?
A Practical Guide
Why does the Moon influence tides?
A Practical Guide
Is the Moon moving away from Earth?
A Practical Guide
What are lunar laser retroreflectors?
A Practical Guide
What is the far side of the Moon?
A Practical Guide
Why is the far side useful for astronomy?
A Practical Guide