New Horizons course correction puts spacecraft on target to Ultima Thule
This composite image of Ultima Thule was taken just 33 hours before the Dec. 2, 2018, course-correction maneuver that fine-tuned New Horizons’ trajectory for its New Year’s 2019 flyby. At left is the full Long Range Reconnaissance Imager or LORRI image, which is an average of 10 individual 30-second exposures, with a yellow circle centered on the location of Ultima Thule. Unlike the LORRI images taken in August through October 2018, Ultima is now evident among the many background stars even without further processing. Nevertheless, Ultima really stands out after subtracting the background stars; the region within the yellow box has been expanded in the star-subtracted version of the image on the right although many artifacts from the imperfect star subtractions are visible in this difference image. Ultima was 4.01 billion miles or 6.47 billion kilometers from the Sun and 24 million miles or 38.7 million kilometers from the New Horizons spacecraft when the images were taken.
Caption & Image Credit: NASA / Johns Hopkins University Applied Physics Laboratory / Southwest Research Institute
NASA’s New Horizons spacecraft conducted the most distant ever course-correction maneuver by any vehicle on Sunday, Dec. 2, firing its thrusters for just 105 seconds to adjust its velocity by approximately 2.2 miles per hour.
Mission engineers conducted the maneuver to refine the spacecraft’s course so it meets the goal of closest flyby of Kuiper Belt Object (KBO) Ultima Thule at 12:33 a.m. EST on Tuesday, Jan. 1, from a distance of just 2,200 miles (3,500 km).
New Horizons was 4.03 billion miles (6.48 billion km) from Earth and just 40 million miles from its second target when the maneuver was carried out on Sunday at 8:55 a.m. EST (12:55 GMT). A radio signal confirming its success was conveyed via NASA’s Deep Space Network (DSN) at 5:15 p.m. EST that day.
Travel time for radio signals from New Horizons back to Earth now takes some six hours, with the signals traveling at the universal speed of light.
Up to three more course-correction maneuvers are under consideration by the team in charge of the mission as the spacecraft closes in on Ultima Thule.
Thirty-three hours before the maneuver, New Horizons‘ Long Range Reconnaissance Imager (LORRI) captured 10 individual 30-second exposures of the KBO that it was heading toward, which the mission team combined and released as a single image. Ultima Thule can now be detected against the background of stars without any image processing. When mission scientists subtract the background stars and expand the section of the image containing the KBO, it can be clearly seen.
“As the New Horizons spacecraft closes in on its target, Ultima Thule is getting brighter and brighter in the LORRI optical navigation images. It’s now standing out much more clearly among the sea of background stars,” said mission project scientist Hal Weaver of the Johns Hopkins University Applied Physics Laboratory (JHUAPL).
From now through Dec. 21, children and adults can select a greeting to beam to Ultima Thule along with their name and email address through a web page set up by the mission for this occasion.
In honor of the upcoming flyby, Queen‘s Brian May, who is also an astrophysicist and who joined the mission team for the Pluto flyby three years ago, will release a new video with original music on Jan. 1 paying homage to New Horizons. He is creating three brief video clips, the first of which has just been released, as previews. About one minute in legnth, this video features the spacecraft’s launch in January of 2006.
Laurel Kornfeld
Laurel Kornfeld is an amateur astronomer and freelance writer from Highland Park, NJ, who enjoys writing about astronomy and planetary science. She studied journalism at Douglass College, Rutgers University, and earned a Graduate Certificate of Science from Swinburne University’s Astronomy Online program. Her writings have been published online in The Atlantic, Astronomy magazine’s guest blog section, the UK Space Conference, the 2009 IAU General Assembly newspaper, The Space Reporter, and newsletters of various astronomy clubs. She is a member of the Cranford, NJ-based Amateur Astronomers, Inc. Especially interested in the outer solar system, Laurel gave a brief presentation at the 2008 Great Planet Debate held at the Johns Hopkins University Applied Physics Lab in Laurel, MD.
