New Horizons/Ralph

The Ralph instrument 

Exploring Pluto & its moons

NASA’s New Horizons mission is shedding light on some of the most distant worlds in our solar system. Over nearly 10 years, the spacecraft traveled more than 3 billion miles to come within 12,500 km (7,400 miles) of Pluto on July 14, 2015.  The instruments onboard began collecting images and other data about the planet and its moons and will take up to 16 months to download all the data collected during the flyby. 

At a speed of 14.7 km/sec (31,000 miles per hour), New Horizons is the first and fastest spacecraft to travel such a great distance to study Pluto, a dwarf planet with a complex system of moons never before seen up-close.

What we did 

Key Instrument Provider

We built the Ralph instrument, a core member of the seven instruments aboard New Horizons, in cooperation with the Southwest Research Institute (SwRI). Ralph includes the Multispectral Visible Imaging Camera (MVIC) and the Linear Etalon Imaging Spectral Array (LEISA), provided by NASA/Goddard. 

Ralph’s suite of detectors is fed by a three mirror telescope with a resolution 10 times higher than the human eye. Small but powerful, Ralph weighs only 23 pounds and uses only about seven watts, the power of a standard night light. The entire telescope operates around 220 K (-60°F).  

Engineer working on Ralph instrument
Ralph instrument

With a resolution as high as 250 meters (800 feet) per pixel, Ralph provided color and black-and-white maps of Pluto’s surface and temperature and mapped the presence of nitrogen, methane, carbon monoxide, water and other materials across the surfaces of Pluto and its moons. Ralph also provided navigation images that were critical to achieving a precise flyby. 

Ralph is a joint project of Southwest Research Institute, Ball Aerospace and NASA’s Goddard Space Flight Center. SwRI’s Dr. S. Alan Stern is the principal investigator for Ralph and the New Horizons mission. The Applied Physics Laboratory at Johns Hopkins University built and operates the New Horizons spacecraft and manages the mission for NASA. 

Hello Pluto!

Ball built the New Horizons Ralph instrument in just 22 months. Watch our engineers look back at the instrument's journey from build to launch to discovery.

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    Hello Pluto!
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    Pluto's Close Up