spaceSpace and Physics

It's Just One Year Until We Visit An Object At The Edge Of The Solar System


Jonathan O'Callaghan

Senior Staff Writer

We won't know what MU69 looks like until after Christmas Day this year. NASA/JHUAPL/SwRI/Steve Gribben

In just under a year, one of the most audacious space missions ever will take place when NASA's New Horizons spacecraft visits an object in the outer Solar System. It will be the most distant object we’ve ever explored, one that could give us a fascinating insight into our own beginnings.

The target is 2014 MU69, a mysterious Kuiper Belt Object (KBO) that orbits a billion miles beyond Pluto – itself visited by New Horizons in July 2015. Thought to be a remnant of the early Solar System, MU69 is a possible binary object no more than 32 kilometers (20 miles) across that’s hiding plenty of secrets.


On January 1, 2019, those secrets are set to be revealed, when New Horizons will swoop past the surface before continuing on its path out of the Solar System. Preparation for this groundbreaking moment begins much earlier, however, with a number of key dates throughout 2018 leading up to the climax.

“This dot in the distance is going to grow brighter and brighter all the way until the very last days of the year,” Alan Stern, New Horizons principal investigator, told IFLScience. “Our project schedule has hundreds of milestones.”

The excitement begins on June 4, when the spacecraft will be woken from hibernation. In August, it will begin taking observational images of the object from afar to ensure it’s on the right track to fly past at a distance of 3,500 kilometers (2,175 miles) – more than three times closer than the Pluto flyby.

In September, the team will start searching for moons orbiting the object, important for ensuring the flyby goes smoothly. From October onwards, the quality of images snapped by New Horizons will surpass that of Hubble, used to discover MU69 in 2014.

A timeline of what New Horizons will be doing in 2018 and 2019. NASA/JHUAPL/SwRI

It won’t be until just after Christmas Day, however, that we actually know what MU69 looks like. Its shape will be revealed just days prior to the flyby, and then just after midnight on New Year’s Day 2019, New Horizons will make its closest approach, sending its images and data back to Earth.

“We’re going to see something that dates back to the formation of the Solar System,” Marc Buie, a New Horizons science team member, said in a statement.

During the flyby, New Horizons will be using all of its instruments, including its camera, to gather as much data as possible – comparable to the Pluto flyby in the quantity of data. It will take until September 2020 to send all of this data back.

This extended phase of the mission is scheduled to continue until 2021, with the rest of New Horizons’ time devoted to studying another two dozen KBOs from a greater distance. The mission isn’t expected to end there, though, as the spacecraft continues on its way out of the Solar System.


“Probably in 2020, we will put together a second extended mission proposal to do more science further out,” said Stern. “There’s no reason we shouldn’t continue to operate out to the 2020s and 2030s.”

There’s even a small possibility that New Horizons could be sent to visit another KBO after it leaves MU69. That will depend on another suitable target being found. None has emerged so far, but the team are constantly on the lookout, considering the unique science this would afford.

For now, all eyes are on MU69. As champagne corks pop on Earth on New Year's Eve, a spacecraft 4 billion miles away will be having a celebration of its own – one that will not be bested for the forseeable future.


spaceSpace and Physics
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  • solar system,

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  • pluto,

  • New Horizons,

  • MU69,

  • encounter