spaceSpace and Physics

New Horizons Is Now Halfway Between Pluto And Its Next Target In The Outer Solar System


Jonathan O'Callaghan

Senior Staff Writer


Artist's impression of New Horizons at MU69. NASA

Time flies when you’re having fun at the edge of the Solar System. NASA’s New Horizons spacecraft is now halfway to its next target, an object in the Kuiper Belt.

In case you forgot, this spacecraft became our first emissary to Pluto on July 14, 2015. But after returning stunning images and data on this dwarf planet, it was sent on a new mission to explore 2014 MU69, which it will fly past on January 1, 2019.


And as of yesterday, it has passed the halfway point to this destination. It was 782.45 million kilometers (486.19 million miles) from Pluto, which is exactly half the distance to this Kuiper Belt Object (KBO). Overall, the spacecraft is 5.7 billion kilometers (3.5 billion miles) from Earth, or about 5.3 light-hours.

“It’s fantastic to have completed half the journey to our next flyby; that flyby will set the record for the most distant world ever explored in the history of civilization,” said Alan Stern, New Horizons principal investigator from the Southwest Research Institute in Boulder, Colorado, in a statement.

This image, taken by New Horizons on January 28, 2017, shows the predicted location of MU69 in the yellow diamond. NASA/JHUAPL/SWRI

Interestingly, while it is halfway there in terms of distance, it is not halfway there in terms of time. That’s because the Sun’s gravitational pull is gradually slowing down the spacecraft, so the second half of its journey will take a bit longer. It will reach the halfway point in time at 5.24pm EDT (10.24pm BST) this Friday, April 7.


Once it arrives at MU69, the visit will be brief, with the spacecraft using its cameras and instruments to study this world in mere hours. But it will be our first ever look at an object so far from Earth, believed to be a remnant of our Solar System’s formation. The object is no more than 40 kilometers (25 miles) across, much smaller than Pluto, which is 2,374 kilometers (1,475 miles) in diameter.

The spacecraft is about to enter a hibernation period of 157 days, which will be the first time it has been turned off since December 6, 2014. When it wakes up again, scientists will use New Horizons to study more than two-dozen KBOs from a distance of the way to MU69. It will see MU69 for the first time in September 2018.

Pluto might be long gone, but there is plenty more excitement to come from New Horizons.


spaceSpace and Physics
  • tag
  • nasa,

  • pluto,

  • kuiper belt,

  • New Horizons,

  • flyby