Is there Ice on the Moon?

Is there Ice on the Moon? Source: aerospacescholars.jsc.nasa.gov Presentation to the Haggerty School March 29th, 2005

What did the Apollo missions to the moon find? • We gathered 382 kilograms of rocks and dirt. None have water! • There are no surface features on the moon made from flowing water!

Now scientists say… The moon may have ice at permanently dark regions near the south pole of the moon. There may be 1 BILLION cubic meters of water! Why are there permanently dark regions near the moon’s poles? Where did this water come from?

Why are there permanently dark regions near the moon’s poles? • Because of the Sun and shadows! • The Sun shines on the moon’s poles at a very low angle • So, the Sun shines at low angles on the moon’s craters, creating shadows.

How do scientists prove this? First, they use spacecraft to look at the lighting of the moon’s poles over one lunar day (29 Earth days)

How do scientists prove this? • Scientists also need to look at lighting of the lunar poles over the whole year. • The angle of the Sun on the Earth changes with the seasons. • The angle of the Sun on the moon changes too! • But we don’t have pictures of the lunar poles through every season. What do scientists do? They create models.

Let’s create a model too!

Coldest Temperature Possible Today Hot Summer Day Temperature in Crater Temperature of Dry Ice -109 deg F 80 deg F -389 deg F Why would there be ice in these permanently shadowed craters? • The moon has many craters. This means meteorites hit it very often. Scientists believe that many, if not most, meteorites have water ice. • Permanently shadowed regions are so cold (-389 deg F) that this water ice in these regions could exist for billions of years!

Why is there no ice elsewhere? • Places on the moon exposed to sunlight can reach 250 deg F. Therefore, water ice from meteorites will evaporate into water vapor. • The moon’s low gravity cannot hold gas for very long and so the water vapor escapes out to space. Coldest Temperature Possible Temperature In Sunlight on Moon Today Hot Summer Day Temperature in Crater Temperature of Dry Ice Boiling -109 deg F 80 deg F 250 deg F -389 deg F

What evidence do we have for ice? • The Clementine spacecraft (in 1996) reflected radio waves off the moon. • Radio waves are reflected in all directions from rocks and dust. • Ice reflects radio waves like a bicycle reflector reflects light. • Is there another explanation for this result?

What other evidence do we have for ice? • The Lunar Prospector spacecraft (in 1998) had an experiment to detect hydrogen on the moon. The experiment was designed to detect very very small amount of water (<0.01%).

What other evidence do we have for ice? • The Lunar Prospector detected 3-4.6% at the moon’s poles.

What other evidence do we have for ice? • Can this hydrogen come from anything other than water?

Why is ice important for manned missions to the moon? • Shipping water to the moon is very expensive. • It costs between $2,000-$20,000 for every kilogram of water sent to the moon. • Each astronaut on the moon will require about 30 kg of water per day!

Why is ice important for manned missions to the moon? • Hydrogen and oxygen is a very good rocket propellant. • Engineers estimate that using water on the moon to make this rocket propellant would make it ten times less expensive to transport people and cargo to and from the moon.

LunarDREEM NASA Competition • We are designing systems that will go to a permanently shadowed crater to check and see if there is ice there • This requires: • A system to gather ice and rock and soil • A system to separate the ice from the rock and soil

System to Gather Lunar Soil and Ice • Drill

System to Separate Ice from Rock and Soil Water Vapor is condensed (cooled) to liquid water Heat up Rock/Soil/Ice Mixture using a Microwave Ice Evaporates to Water Vapor

Questions?

Is there Ice on the Moon?