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New Horizons begins Pluto encounter operations

Elizabeth Howell, News Writer
Jan 15, 2015, 18:03 UTC

Sen—It was almost exactly 85 years ago that Pluto—once considered the farthest planet of our Solar System—came to light in images examined by astronomer Clyde Tombaugh. Today NASA's New Horizons probe, on its way to study it, began operations to prepare for the encounter.

The dwarf planet is so far and so small that it always appeared as a point of light or a smudge in our telescopes, no matter how big or how powerful.

That is all about to change. In July of this year, New Horizons will cap nearly a decade of flying through space by taking images of Pluto and its various moons. Catching a glimpse of Pluto's surface and atmosphere is expected to give astronomers a better idea of how the Solar System formed.

"Next year, New Horizons will be taking the first high-resolution views of the Pluto system, which represents an unexplored class of Solar System bodies—small planets in the Kuiper Belt," wrote Dennis Reuter, the New Horizons co-investigator, in a December blog post on the Johns Hopkins Applied Physics Laboratory website. 

"While we have some idea of what we expect to see, I can’t help but think that history will repeat itself, and we’ll find ourselves astounded by something new, something we had never expected to see."

For most of its journey towards Pluto, New Horizons has been asleep to conserve energy and also preserve its instruments for the big close-up. On occasion, controllers turned it on to do checkouts of the instruments, upload software updates, and to take distant pictures of Pluto and its moons.

New Horizons also was awoken before it flew past Jupiter in 2007, allowing it to take a spectacular set of images and collect data from the Solar System's largest planet and its moons.

In December, New Horizons ended its last lengthy hibernation before Pluto. According to principal investigator Alan Stern, it was a busy few weeks prior to the beginning of Pluto operations today (15 January).

"Since waking New Horizons, we’ve been checking out spacecraft systems and some of the instruments, calibrating gyroscopes, collecting trajectory tracking information, and undertaking many other spacecraft preparations," he wrote in a blog post in late December.

"At the same time, our science, engineering and operations teams have been planning and testing spacecraft command loads (detailed flight plans) for the first parts of encounter operations in early 2015."

Pluto is still 220 million km (135 million miles) from the spacecraft, too far away for the probe yet to capture pictures better than Hubble has managed. Nevertheless, the spacecraft has many duties to perform in the coming weeks, up until mid-May.


When New Horizons zoomed by Jupiter and its moons in 2007, it captured changes in the volcanic Io since this Galileo view in 1999. Image credit: NASA/JHUAPL

Every day in the next few months, the spacecraft will take measurements of dust, the solar wind and high-energy particles in the region near Pluto. Meanwhile, NASA's Deep Space Network of radio telescopes will keep close track of the spacecraft to assist with its path to the dwarf planet, and the spacecraft's Long-Range Reconnaissance Imager (LORRI) will image Pluto hundreds of times to monitor New Horizons' distance to its target. All this information will help controllers figure out if they need to burn the engines for a course correction in March.

Some of the extensive imagery planned, Stern added, includes movies of Pluto and its satellites and by April, some colour pictures of the dwarf planet and its largest moon, Charon.

"These datasets will provide important science information because they will be taken from angles that can’t be observed from Earth, and taken more frequently than observations we typically make from the ground. We plan to release results from these approach observations one to several times each month, at a pace that quickens with time," he wrote.

After Pluto, it's possible that New Horizons will fly past a more distant Kuiper Belt object. This follows imagery that the Hubble Space Telescope took in support of this goal in June and July. A budget request will be made in 2016 to see if NASA has the funds available to support another flyby.