We're There! New Horizons Begins Approach Phase 1

On January 15, exactly six months before its closest flyby of the Pluto system, NASA's New Horizons mission officially began the first of three approach phases, meaning its instruments will now begin taking pictures of the planet and its five moons.

Approach Phase 1, which will last until April 4, coincides with several major anniversaries. January 19 marks the ninth anniversary of the mission's launch from Cape Canaveral. Patsy Tombaugh, widow of Pluto discoverer Clyde Tombaugh, then in her 90s, attended the launch. It was a special event for her because some of her husband's ashes are onboard the New Horizons spacecraft.

Patsy had hoped to see the flyby and came reasonably close to doing so. She died at age 99 in 2012. Had she lived, she would now be 102.

Tombaugh took the photographic plate images from which he would discover Pluto on January 21, 23, and 29, 1930.

New Horizons has traveled farther and faster than any other mission toward its primary target. Its nine-year journey traversed three billion miles, to this and as yet unexplored zone of the solar system.

Pluto and its moons will appear as faint dots in the photos taken during this first approach phase. Their purpose is not to provide the impressive close-up images for which so many are waiting. These pictures are being taken for the purpose of optical navigation.

The spacecraft is still 100 million miles from Pluto, and it is traveling at an incredible speed of 27,000 miles per hour. At that speed, impacting even the tiniest piece of dust or debris would destroy it completely.

On January 25, New Horizons' Long Range Reconnaissance Imager (LORRI), a long focal length telescopic instrument, began taking high resolution photos of the Pluto system in visible wavelengths for the specific purpose of finding any debris that could threaten the mission. If necessary, a course correction maneuver to avoid such debris will be undertaken.

LORRI's images will serve another important purpose. They will enable the mission team to obtain precise measurements of Pluto's orbital position and its exact distance from New Horizons.

“The flyby timing has to be exact, because the computer commands that will orient the spacecraft and point the science instruments are based on precisely knowing the time we pass Pluto–which these images will help us determine,” explained Mark Holdridge, encounter mission manager at Johns Hopkins University Applied Physics Lab (JHUAPL).

LORRI's third goal during this period is observing the dynamics between Pluto and its moons.

At closest approach, the probe will come within 7,700 miles of the Pluto system though it will not orbit the small planet.

Even in this first approach phase, New Horizons will be doing science. Its instruments will measure high energy charged particles in the solar wind and the concentration of dust particles in this region.

With its actual work underway, New Horizons is getting significant media coverage worldwide, as is Pluto. This coverage is raising tremendous awareness about the mission. At the same time, many writers and media outlets are once again repeating the old standby that Pluto was a planet at the time New Horizons was launched but is no longer "officially" a planet now.

This reporting is unfortunate and misleading. Pluto is very much a planet to many planetary scientists and to many on the New Horizons team. There is no scientific reason to give so much weight to the 2006 IAU decision, to grant it an "official" status it does not merit. There is no scientific reason for writers to state that our solar system has only eight planets. After all, it was New Horizons Principal Investigator Dr. Alan Stern who first coined the term "dwarf planet," and his intention was to designate a third class of planets, not to refer to non-planets.

Now is Pluto's moment to shine, its time in the spotlight. Pluto will speak for itself, and I am far from alone in being confident its features will clearly "say" planet.

As Dr. Stern says, “What I am most excited about is taking this point of light and transforming it into a planet.”

There are many ways to follow this exciting mission online. Here are some good sites to watch and follow regularly.

The New Horizons mission website: http://pluto.jhuapl.edu/
NASA's New Horizons website: http://www.nasa.gov/mission_pages/newhorizons/main/index.html
Pluto encounter countdown: http://seeplutonow.com/
New Horizons e-news signup: http://pluto.jhuapl.edu/signup/index.php
New Horizons email alerts: http://guinan.space.swri.edu/nhepo/majorevents
New Horizons Twitter feed: https://twitter.com/NASANewHorizons
Principal Investigator Alan Stern's Twitter feed: https://twitter.com/NewHorizons2015
Pluto Picture of the Day: http://www.boulder.swri.edu/ppod/
New Horizons on Facebook: https://www.facebook.com/new.horizons1

The February 2015 issue of Astronomy magazine, both in print and online, has a good write up on the New Horizons mission. See http://www.astronomy.com/issues/2015/february-2015 .

In addition to following the mission on this blog, I will also be writing about New Horizons for an exciting new website, Spaceflight Insider. Its main page is http://www.spaceflightinsider.com , and it covers all the news on spaceflight, manned and unmanned, including regular updates on the Dawn mission to Ceres. My latest article on New Horizons can be found at http://www.spaceflightinsider.com/missions/solar-system/new-horizons-starts-first-phase-pluto-encounter/ .

Get ready for a wild ride ahead!