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Pathways to Pluto - Part 2 of 2: The Dream Machine

by Perry Pezzolanella, MVAS

The cost of a spacecraft to Pluto kept ending up expensive no matter who attempted to design it. The latest spacecraft under development, Pluto-Kuiper Express, soared past one billion dollars and by September 2000 the mission was cancelled. This created a huge uproar among everyone from the science community to schoolchildren. Petitions circulated and this time Congress and NASA listened. NASA reopened the chance to explore Pluto to the science community by letting several independent teams design a new mission, provided the cost could be capped at $650 million.

Several ideas were proposed and on November 29, 2001 the mission to Pluto was reborn when New Horizons, designed by the John Hopkins University/Applied Physics Laboratory (JHU/APL), was chosen. The name said it all because Pluto and the Kuiper Belt were a whole new distant horizon in the Solar System which was ripe for exploration and discovery. New Horizons was to be a larger and more capable spacecraft than any other ever designed and carry seven experiments versus three for Pluto Kuiper Express. It would use the most powerful booster of all, the tried-and-true Atlas V rocket.

The Atlas V would guarantee that New Horizons would get to Pluto in about nine years, provided the spacecraft used Jupiter's powerful gravity to give it an additional boost. Fortunately, two launch windows were approaching where Jupiter would be in the right position to give New Horizons a swift kick to Pluto. One launch window opened on December 18, 2004 that would send New Horizons past Pluto as early as December 24, 2012 for a beautiful Christmas present for the scientific world and to all who were interested in Pluto. The second launch window would open on January 11, 2006 and send New Horizons past Pluto as early as July 14, 2015 for a slightly belated U.S. Independence Day reason for a celebration.

Focus was the mantra of the New Horizons team, which kept the cost down by using tried and true technology; only experiments designed for what was actually needed for a successful mission were included with no fancy extras such as Pluto atmospheric probes or hard landers. Sticking with this, a successful Pluto encounter would include the best imaging possible of Pluto, its moons, and any potential rings along with a thorough mapping of the chemical composition of the surfaces, the atmosphere, and a complete map of any magnetic field. The spacecraft would hardly weigh more than 1000 pounds and would be no larger than a grand piano, but just like the school-bus sized, 6-ton Cassini Saturn orbiter, it was designed as a dedicated spacecraft capable of serious exploration. This focused concept kept the mission close to the $650 million cap and was able to meet the 2006 launch deadline. The instruments were designed to be energy efficient and include:

  • Alice: An ultraviolet imaging spectrometer that will probe the composition and structure of Pluto's atmosphere.
  • Ralph: This is the main eye of New Horizons. It will take the first good look at the fringe worlds and will map Pluto, its moons, and selected Kuiperoids. Ralph and Alice are coupled to work in unison and were named after the famous characters of "The Honeymooners" TV show.
  • REX (Radio Science Experiment): A simple circuit board that is tied into the telecommunication system which will measure atmospheric temperature and pressure.
  • LORRI (Long Range Reconnaissance Imager): The eagle eyes of New Horizons will study geology by producing the highest resolution images possible. It is an 8.2-inch telescope with a CCD camera that can resolve details as small as 150 feet.
  • SWAP (Solar Wind at Pluto): This instrument will study the interaction of Pluto with the solar wind along with the escape rate of Pluto's atmosphere into space.
  • PEPSSI (Pluto Energetic Particle Spectrometer Science Investigation): An extremely sensitive instrument that will study the density, composition, and nature of the energetic particles and plasmas of Pluto's atmosphere as they escape into space.
  • SDC (Student Dust Counter): This instrument was built by students at the University of Colorado at Boulder and will measure the concentration of dust particle in the outer Solar System. It is the first science instrument on a planetary mission to be designed and built by students.

Even though New Horizons was nearly built with all the instruments designed and in the process of being tested, Congress continued to threaten funding, which was actually absent in the 2003 budget. Through clever intervention of the scientific community, the funding was restored every time. A shortage of plutonium oxide in 2004, which would power the scientific instruments, and damage to a booster from Hurricane Wilma in 2005 threatened to compromise or seriously delay the mission, but engineers and scientists pulled through to make sure that New Horizons would be ready for launch by the opening of the launch window on January 11, 2006. Another gremlin struck as cracks were detected in several of the trusty Atlas rockets late in 2005, therefore the Atlas rocket that was attached to New Horizons also had to be tested. The launch date slipped to January 17, 2006, but fortunately no cracks were detected.

Finally the day everyone awaited for arrived; New Horizons was ready for launch towards Pluto. Unfortunately, a January 17 launch was not to be as high winds throughout Florida scrubbed the launch. The gremlins seemed to work overtime; the weather at Cape Canaveral, Florida was good on January 18, but a violent thunderstorm knocked out the power to the command center at the John Hopkins University in Laurel, Maryland so it was impossible to launch that day. Finally, on January 19, 2006 at 2 P.M. EST, New Horizons roared into space beautifully and flawlessly as the fastest spacecraft ever launched from Earth, reaching a speed of 36,256 miles per hour.

With a successful launch, New Horizons will officially fly within 6200 miles of Pluto on July 14, 2015 after a gravity assist from Jupiter on February 28, 2007. At last, a dream that was so hard to bring to reality, taking 17 years to get from Washington, D.C. to Florida, but only taking about 9 _ years to get from Florida to Pluto, is coming true. Hard work, dedication, and perseverance led to the ultimate pathway to Pluto and the Kuiper Belt, enriched with the promise of adventure and discovery.

New Horizons Flight Facts:
It passes the orbit of:

  • Mars 4/7/06
  • Jupiter 2/28/07 (actual encounter)
  • Saturn 6/8/08
  • Uranus 3/22/11
  • Neptune 8/29/14
  • Pluto 7/14/15 (actual encounter)