The Ralph Instrument
Exploring Pluto & Its Moons
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.
Ralph New Horizons
Download this PDF to learn more about the instrument responsible for returning the first high-resolution images of Pluto.
What We Did
Key Instrument Provider
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).
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.
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.