National Aeronautics and Space Administration Logo
Follow this link to skip to the main content NASA Banner
Solar System Exploration
Facebook Twitter YouTube Facebook Twitter YouTube Flickr iTunes
Follow Us
Moons

The Spacecraft
Observing Surface of Moons

NIMS Observation of Europa
NIMS Observation of Europa

You might think that the moons of a planet are all alike -- but the opposite is true. We want to study features on the surface, like mountains, valleys, lava flows, and craters. Is the surface rock or ice -- and what kind? The information helps scientists write the history of each moon, and figure out why a particular moon looks the way it does today. Galileo's camera gives us stunning visual images of these strange worlds, with their volcanoes, craters, or icy terrain. The NIMS identifies the minerals that make up the surface.

Infrared image of Europa taken with Galileo's PPR instrument
This infrared image of Europa, showing heat radiation, was taken with Galileo's PPR instrument

What is the texture of rocks and ice on the surface? Is the surface hard ... or loose.... sandy... fine-grained.... clumpy? The PPR determines the size of crystals on the surface by looking at light that has been polarized by these crystals. Polarization can reveal information about the nature of the object that is reflecting the light. We take advantage of it on Earth by wearing sunglasses with polarized lenses that give a "cool" view of brightly lit objects.

What is the environment on the surface of a moon like? Is it hot, or cold? And how hot or cold? By measuring the infrared light emitted from the surface, NIMS and the PPR can take a moon's temperature.

Next: Observing Magnetic Fields Next

Spacecraft
Mission Operations
Awards and Recognition   Solar System Exploration Roadmap   Contact Us   Site Map   Print This Page
NASA Official: Kristen Erickson
Advisory: Dr. James Green, Director of Planetary Science
Outreach Manager: Alice Wessen
Curator/Editor: Phil Davis
Science Writer: Autumn Burdick
Producer: Greg Baerg
Webmaster: David Martin
> NASA Science Mission Directorate
> Budgets, Strategic Plans and Accountability Reports
> Equal Employment Opportunity Data
   Posted Pursuant to the No Fear Act
> Information-Dissemination Policies and Inventories
> Freedom of Information Act
> Privacy Policy & Important Notices
> Inspector General Hotline
> Office of the Inspector General
> NASA Communications Policy
> USA.gov
> ExpectMore.gov
> NASA Advisory Council
> Open Government at NASA
Last Updated: 9 Jul 2010