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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| 486958 Arrokoth | 8/8 | https://en.wikipedia.org/wiki/486958_Arrokoth | reference | science, encyclopedia | 2026-05-05T13:09:12.451441+00:00 | kb-cron |
Having completed its flyby of Pluto in July 2015, the New Horizons spacecraft made four course changes in October and November 2015 to place itself on a trajectory towards Arrokoth. It is the first object to be targeted for a flyby that was discovered after the visiting spacecraft was launched, and is the farthest object in the Solar System ever to be visited by a spacecraft. Moving at a speed of 51,500 km/h (858 km/min; 14.3 km/s; 32,000 mph) New Horizons passed by Arrokoth at a distance of 3,538 km (2,198 mi), equivalent to a few minutes of travel at the craft's speed, and one third of the distance of the spacecraft's closest encounter with Pluto. Closest approach occurred on 1 January 2019, at 05:33 UTC (Spacecraft Event Time – SCET) at which point it was 43.4 AU from the Sun in the direction of the constellation Sagittarius. At this distance, the one-way transit time for radio signals between Earth and New Horizons was 6 hours. New Horizons closest approach was towards the celestial north of Arrokoth. Owing to Arrokoth's tilted rotation (with its rotational axis south pole facing towards the Sun), the rotational north pole hemisphere was mostly in darkness during New Horizons flyby. The science objectives of the flyby include characterizing the geology and morphology of Arrokoth, and mapping the surface composition (searching for ammonia, carbon monoxide, methane, and water ice). Surveys of the surrounding environment to detect possible orbiting moonlets, a coma, or rings, were conducted. Images with resolutions showing details of 30 m (98 ft) to 70 m (230 ft) are expected. From Hubble observations, faint, small satellites orbiting Arrokoth at distances greater than 2,000 km (1,200 mi) have been excluded to a depth of >29th magnitude. The object has no detectable atmosphere, and no large rings or satellites larger than 1.6 km (1 mi) in diameter. Nonetheless, a search for a related moon (or moons) continues, which may help better explain the formation of Arrokoth from two individual orbiting objects. New Horizons made its first detection of Arrokoth on 16 August 2018, from a distance of 172 million km (107 million mi). At that time, Arrokoth was visible at magnitude 20, in the direction of the constellation Sagittarius. Arrokoth was expected to be magnitude 18 by mid-November, and magnitude 15 by mid-December. It reached naked eye brightness (magnitude 6) from the spacecraft's point of view just 3–4 hours before closest approach. If obstacles were detected, the spacecraft had the option of diverting to a more distant rendezvous, though no moons, rings or other hazards were seen. High-resolution images from New Horizons were taken on 1 January. The first images of mediocre resolution arrived the next day. The downlink of data collected from the flyby was expected to last 20 months, through September 2020.
== Gallery ==
== See also ==
List of minor planets and comets visited by spacecraft 132524 APL – Another minor planet visited by New Horizons List of trans-Neptunian objects
== Notes ==
== References ==
== External links ==
Arrokoth (2014 MU69): Most Distant Object Explored Up Close at NASA Solar System Exploration About Arrokoth (2014 MU69) LORRI Images from the Arrokoth Flyby 486958 Arrokoth at AstDyS-2, Asteroids—Dynamic Site Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info 486958 Arrokoth at the JPL Small-Body Database