New Horizons Chooses Flyby Target for Extended Mission


WASHINGTON — As an encore to their successful Pluto flyby, the team behind the New Horizons probe is planning a close pass of the distant Kuiper Belt object 2014 MU69, which orbits the sun more than 1.5 billion kilometers beyond Pluto.

The flyby, which would take place in January 2019, is contingent on New Horizons receiving extended mission funding from NASA’s planetary science division. The New Horizons team will submit an extended mission proposal some time next year, NASA said in an Aug. 28 press release. NASA will take about a year to review that and other extended mission proposals.

The Kuiper Belt is a ring of millions of small worlds beyond Pluto’s orbit. Scientists believe Pluto itself is a Kuiper Belt object that somehow got trapped in its current orbit.

Since 2011, ground- and space-based telescopes, including the Hubble Space Telescope, have been searching for Kuiper Belt objects New Horizons might be able to reach with whatever fuel was left in its tanks after its mission to Pluto. The search was narrowed down to five finalists over the last year. The easiest of the five to reach, NASA said, was 2014 MU69.

New Horizons will get “a lot closer” 2014 MU69 than it got to Pluto, Alan Stern, the mission’s principal investigator, said at an Aug. 25 meeting of the NASA-chartered Outer Planets Assessment Group. Pluto is about 1,200 kilometers in diameter; 2014 MU69 is only about 45 kilometers in diameter.

Because orbital mechanics are indifferent to the management protocols of NASA’s Science Mission Directorate, the New Horizons team must begin preparing for the 2014 MU69 encounter now, lest they miss the opportunity to put the spacecraft on the correct course.

Once a NASA planetary science spacecraft or lander has accomplished its primary task, the team operating it must seek funding for an extended mission or switch off the spacecraft. NASA reviews batches of operating missions about every two years to determine if it is scientifically worthwhile to keep funding them. Most missions continue for as long as they are physically able to operate.