New Horizons Mission Images Pluto’s Largest Moon Charon
April Flowers for redOrbit.com – Your Universe Online
NASA’s New Horizons spacecraft has been Pluto-bound since its launch January 19, 2006. Using its highest-resolution telescopic camera, the Long Range Reconnaissance Imager (LORRI), New Horizons has spotted Pluto’s Texas-sized, ice covered moon Charon for the first time, representing a major milestone on the 9.5 year journey. The spacecraft’s mission is to conduct initial reconnaissance of the Pluto system and the Kuiper Belt, and this series of images begins the mission’s long-range study.
The six images were taken on July 1 and July 3, 2013, when New Horizons was still approximately 550 million miles from Pluto – farther than the distance from Earth to Jupiter. The images revealed Charon at exactly the predicted offset from Pluto. The spacecraft is scheduled to pass just 7.750 miles above Pluto’s surface on July 14, 2015. This distance will allow LORRI to be able to spot features about the size of a football field.
Charon is the largest of Pluto’s five moons, orbiting about 12,000 miles away from Pluto’s surface. The moon was discovered 35 years ago by James Christy of the Naval Observatory. At New Horizons’ current vantage point, Charon is only about 0.01 degrees away from Pluto.
“The image itself might not look very impressive to the untrained eye, but compared to the discovery images of Charon from Earth, these ‘discovery’ images from New Horizons look great!” says New Horizons Project Scientist Hal Weaver of the Johns Hopkins University Applied Physics Laboratory. “We’re very excited to see Pluto and Charon as separate objects for the first time from New Horizons.”
“In addition to being a nice technical achievement, these new LORRI images of Charon and Pluto should provide some interesting science too,” says New Horizons Principal Investigator Alan Stern of the Southwest Research Institute. New Horizons is currently viewing Pluto and Charon at solar phase angles – the angles between the Sun, Pluto and spacecraft – much larger than any Earth-based, or near-Earth observatory can achieve. This could potentially yield important information about the surface properties of both celestial bodies. For example, LORRI images might show the existence of an overlying layer of fine particles.
“We’re excited to have our first pixel on Charon,” Stern continues, “but two years from now, near closest approach, we’ll have almost a million pixels on Charon, and I expect we’ll be about a million times happier too!”
Image 2 (below): Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute