NASA's New Horizons spacecraft, which was flown by Pluto in July 2015, woke today from hibernation mode to prepare for their next rendezvous with a space rock on the edge of the solar system. The vehicle came out of its sleep 3.7 billion miles from Earth as it lashed out on an icy body nicknamed Ultima Thule, orbiting the sun far beyond Neptune. Now that the spacecraft is awake, the mission team will have a full schedule by 2018: the flyby will take place on January 1, 2019.
New Horizons has gone into hibernation twice since April 2017. Hibernation, the spacecraft basically runs on autopilot, with only its essential components and some of its instruments turned on. The probe also works with a long list of commands uploaded to the spaceship's memory before snaps it off. All of this helps to reduce spacecraft wear and minimize the mission team's work on the ground.
New Horizons mission team sent orders to wake the vehicle out of its six-month hibernation on June 4 and early morning. This morning, the spacecraft sent a signal confirming it was officially operational. For the next two and a half months, Bowman says they'll take care of the spacecraft, such as testing and uploading new software. This includes downloading scientific data collected during hibernation and data stored in the vehicle's recorder.
Then on August 13 The New Horizons team will bring the spacecraft out of its spin state, which contributes to it to keep the probe stabilized. And in the middle to the end of August they will try to photograph the target of the vehicle, Ultima Thule, with one of the New Horizons cameras. The Space Rock is located in the Kuiper Belt – the big cloud of icy bodies beyond Neptune. "We think we'll see it first," says Bowman.
After August New Horizons finishes with Ultima Thule, and then the team is in crisis. They plan and refine the exact commands needed for the spacecraft's flyby sequence. And that's going to be difficult considering the goal: Ultima Thule is small, only about 20 to 23 miles across, or nearly twice as long as the island of Manhattan. (By comparison, Pluto is nearly 1500 miles in diameter.) It's a dark body in front of a bright field of stars, making it hard to see. And the team wants to fly closer to Ultima Thule than to Pluto. "We have a lot to do," says Bowman. "It will be very difficult."
The challenge is that New Horizons is now incredibly far from Earth, making communication with the spaceship a lengthy process. A radio signal takes about 12 hours to travel to and from the spacecraft – three hours longer than the orbital period in Pluto. In the next six months, the spacecraft will also collect a lot of data. The mission team will upload commands every few weeks instructing the vehicle to compress and erase the data to make room on the vehicle computer. That means they will have a lot of work and a lot to wait for.
Then in October, New Horizons will fire his thrusters and make the first of seven maneuvers to change trajectory. The deadline is December 22nd, and on Christmas Day the flyby sequence begins. Today's milestone is only the beginning of many exciting things that will come for New Horizons. Or, as Bowman says, "It's the beginning of something great."