'New Horizons' zeroes in on Pluto

When I was a kid, the best image of Pluto from Mount Palomar was a fuzzy dot. The great Hubble Space Telescope later gave us a fuzzy ball, which wasn’t much more satisfying. Something drastic had to be done about this problem. So in 2006, America vented its frustration by sending a grand-piano-sized probe called New Horizons to take a very good look at Pluto and its moons.

We are a patient people. Now it is time to savor and celebrate. After over nine years in space, New Horizons will make its historic close encounter on July 14th. Although New Horizons will scream through the Pluto-system in just a few hours, the results of its 21st century technology will leave the veterans of the Mariner, Pioneer, and Voyager Programs in awe!

New Horizons is capable of far more than taking beautiful color pictures; it also measures high-energy particles streaming from the sun and dust-particle concentrations; its solar wind and energetic particle spectrometers will measure the rate at which Pluto’s atmosphere is escaping into space. As the probe passes close to Pluto, it will be receiving signals beamed to it from four of the massive antennas at NASA/JPL’s Deep Space Tracking Network near Barstow. The signals will pass through Pluto’s (and perhaps Charon’s) atmosphere and be received by the Radio Science Experiment to tell us much about their atmospheric temperatures, pressures, and even surface properties and body mass.

New Horizons was awakened from seven cumulative years of deep slumber on December sixth. It started taking images of Pluto on January 25th for navigation purposes. Now three billion miles from home, roundtrip messages at the speed-of-light take nine hours! Therefore, the probe is executing its maneuvers on its own in accordance with a highly detailed program that it has been rehearsing along the way.

The images captured by New Horizons’ telescopic Long-Range Reconnaissance Imager (LORRI) give mission scientists a continually improving look at the dynamics of Pluto’s moons. The images also will play a critical role in navigating the spacecraft as it covers the remaining distance to Pluto. “We’ve completed the longest journey any spacecraft has flown from Earth to reach its primary target, and we are ready to begin exploring,” said Alan Stern, New Horizons principal investigator from Southwest Research Institute in Boulder, Colorado.

The furthest primary mission objective for a space probe has heretofore been Saturn. The Cassini probe has been doing a truly marvelous job sending back amazing views of that planet, its rings, and its satellites for over a decade. Yet, New Horizons has tripled Cassini’s distance record. Along with the Voyager fly-bys of Uranus and Neptune, NASA will have close-up images and detailed data on all nine of the “traditional planets;” and the Voyagers are now venturing into interstellar space. That’s quite an achievement for NASA, America, and Humanity!

I recently heard a NASA program manger asked what he would do with an infinite amount of money. He said that he couldn’t imagine that. What makes their job fun and interesting is that they don’t have an infinite amount of resources. They have to be clever and bold with what’s available. Well, those people at NASA sure are good at it!

Pluto has five known satellites, or moons. New Horizons is going to fly inside of their orbits, providing a good vantage for imaging two of them. The largest, Charon, was discovered in 1978 by the U.S. Naval Observatory. It’s quite large for a moon, nearly 1/9 the mass of Pluto itself. The other four were actually discovered after the probe left on its mission. Orbital mechanics will not allow close examination of all four on a fly-by mission. However, Nix, the second largest moon, is squarely in the probe’s sights.

New Horizons will skim 12,500 km from the surface of Pluto, far lower than a GPS satellite orbit. Closest approach will be on July 14th at 4:50 a.m., Tehachapi Time. However, don’t bother getting out of bed for the big show! Unfortunately, we won’t be privy to live images of the fly-by. New Horizons can’t point its antenna independently of its camera; the spacecraft must turn as one. Therefore, it will be busy take taking pictures, not beaming them home right away.

The spacecraft will continue to maintain focus on the Pluto system for another six days while Pluto completes an entire turn on its axis (a Plutonian day). Then it will finally turn toward earth and begin downloading a compressed set of images on July 20th (Apollo 11 Day!), after which it will continue its vigil as it continues to scream away into the distant reaches of the Kuiper Belt. It won’t begin to download its complete store of data until September 14th. However, due to the distance involved and the richness of the data, it will take eighteen months to empty its memory banks. Let’s hope it doesn’t meet up with a meteor before then!

Pluto will not be New Horizons’ final destination. While it’s been in hibernation, NASA has been using the Hubble Space Telescope to find another Kuiper Belt Object (KBO) for New Horizons to explore. These bodies are believed to be remnants of the early days of the formation of the Solar System and may be able to tell us much about how it all came about. Three possible targets have been identified, all far smaller than Pluto. A decision is due by the end of this year, at which time New Horizons will fire its thrusters and set a new course to arrive in late 2018 or early 2019. Stay tuned to Tehachapi Sky Watch for more on this far out space probe!

The New Horizons project is run for NASA by some very bright people at Johns Hopkins University’s Applied Physics Laboratory in Laurel, Maryland. To learn more about the project or to follow its progress, go to http://www.nasa.gov/mission_pages/newhorizons/main/. You can also follow its progress on NASA TV.