New Horizons Corrects Its Course In The Kuiper Belt

The New Horizons spacecraft is about 300 million miles (483 million kilometers) from 2014 MU69, the Kuiper Belt object it will encounter on Jan. 1, 2019. Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

December 11, 2017 – NASA’s New Horizons spacecraft carried out a short, 2.5-minute engine burn on Saturday, December 9 that refined its course toward 2014 MU69, the ancient Kuiper Belt object it will fly by a little more than a year from now.

Setting a record for the farthest spacecraft course correction to date, the engine burn also adjusted the arrival time at MU69 to optimize flyby science.

Telemetry confirming that the maneuver went as planned reached the New Horizons mission operations center around 11 a.m. MST (1 p.m. EST) at the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland, via NASA’s Deep Space Network (DSN) stations in Goldstone, California. The radio signals carrying the data traveled over 3.8 billion miles (6.1 billion kilometers) and took five hours and 41 minutes to reach Earth at the speed of light.

Operating by timed commands stored on its computer, New Horizons fired its thrusters for 152 seconds, adjusting its velocity by about 151 centimeters per second, a little more than three miles per hour. The maneuver both refined the course toward and optimized the flyby arrival time at MU69, by setting closest approach to 12:33 a.m. EST (5:33 UTC) on January 1, 2019. The prime flyby distance is set at 2,175 miles (3,500 kilometers); the timing provides better visibility for DSN’s powerful antennas to reflect radar waves off the surface of MU69 for New Horizons to receive – a difficult experiment that, if it succeeds, will help scientists determine the reflectivity and roughness of MU69’s surface.

The maneuver was the last trajectory correction during the spacecraft’s long “cruise” between Pluto, which it flew past in July 2015, and the MU69 flyby. New Horizons Mission Design Lead Yanping Guo, of APL, said the next course-correction opportunity comes in October 2018, at the start of the MU69 approach phase. The mission team is using data from NASA’s Hubble Space Telescope and the European Space Agency’s Gaia mission to hone its aim toward MU69, which was discovered in 2014.

“We are on course and getting more excited all the time; this flyby is now barely a year away!” said New Horizons Principal Investigator Alan Stern, of the Southwest Research Institute, Boulder, Colorado.

The mission team will put the New Horizons spacecraft into hibernation mode on December 21, where it will stay until early next June. The spacecraft is healthy and speeding away from the Sun at 31,786 miles (51,156 kilometers) per hour, or over 750,000 miles (1.2 million kilometers) per day.