At the edge of our solar system lies a frigid double planet that has never been visited by spacecraft -- Pluto. NASA's Goddard Space Flight Center, Greenbelt, Md., has joined a team led by the Southwest Research Institute (SwRI), San Antonio, Texas, to begin preliminary design studies for what could be the first spacecraft to visit this remote world -- the New Horizons mission.
Goddard will provide an infrared spectrometer, called the Linear Etalon Imaging Spectral Array (LEISA), to the camera system on board the New Horizons spacecraft. A spectrometer breaks light down into its component colors, much like a prism separates white light into a rainbow. Each compound emits a unique pattern of colors, like an optical barcode. By separating light from a celestial object into various distinct colors, a spectrometer reveals the optical barcode of any material present. With this information from LEISA, astronomers will determine what Pluto and Charon, Pluto's unusually large moon, are made of, at least on their surfaces.
"We are thrilled to collaborate with the Goddard Space Flight Center," said Dr. Alan Stern of SwRI, Principal Investigator for the New Horizons mission. "Goddard has world-class people and world-class technology."
"Pluto is nearly three billion miles from the Sun, more than thirty times farther away than Earth, so remote, very little is known about it," said Dr. Donald Jennings, a Co-Investigator for New Horizons at Goddard. "Even with the Hubble Space Telescope, Pluto's surface features remain a tantalizing blur. Sending a spacecraft for a close-up view is the only way to learn more about Pluto, whose moon, Charon, is so large that Pluto qualifies as a double planet."
Congress provided $30 million in fiscal 2002 to initiate the spacecraft and science instrument development and launch vehicle procurement for a Pluto-Kuiper Belt mission; however, no funding for subsequent years is included in the administration's budget plan.
If the design passes a NASA review and the mission is fully funded by Congress, New Horizons will be sent to explore Pluto, whose orbit takes it farther from the Sun than any planet in the solar system. Pluto is the largest member of the Kuiper Belt. Kuiper Belt Objects (KBOs) are a class of relatively small worlds at the fringe of our solar system, possibly hundreds of millions strong, composed of material believed to have been left over after the formation of the other planets.
The New Horizons mission, planned for launch in January 2006, will explore a number of KBOs after it flies past Pluto between 2016 and 2018. The mission's exact arrival time at Pluto depends on the rocket selected to launch the spacecraft. On the way to Pluto, the New Horizons spacecraft will pass close to Jupiter, gaining a boost from the giant planet's gravity to achieve the speed necessary to reach the outer solar system in a reasonable amount of time. This flight path will present the next opportunity to explore Jupiter's exotic moons, and the mission intends to take full advantage of it.
"Pluto's extreme distance makes it the only planet unexplored by spacecraft," said Dr. Dennis Reuter, sensor program manager for LEISA. "It's an extraordinary challenge to reach. To travel to Pluto in a practical amount of time and survive the trip, the spacecraft and its instruments must be built with unprecedented reliability, low weight, and low power consumption."
The camera team will provide a camera and instrument package called the Pluto Express Remote Sensing Investigation (PERSI) that weighs less than 22 pounds and consumes less than seven watts of power. The package is comprised of three subsystems. First is a system of six cameras, to be provided by Ball Aerospace, Boulder, Colo., called the Multi-spectral Visible Imaging Camera (MVIC). MVIC will take detailed pictures of Pluto and Charon. It is called a multi-spectral camera because it is capable of making images with various kinds of light: visible light, ultraviolet light, and infrared light. Ultraviolet and infrared light are not visible to the human eye.
Second is LEISA, the infrared spectrometer to be provided by Goddard. The third subsystem is an ultraviolet spectrometer, to be provided by SwRI, called Alice because it's such a nice name. Alice will analyze ultraviolet light to reveal the composition of Pluto's extremely tenuous atmosphere. Ball will be responsible for assembling the three PERSI subsystems into a complete package.
"Each instrument team is among the best in its field, so we combined our strengths for the New Horizons camera system, providing a package smaller and less costly than previously possible, which is ideally suited to the Pluto and Kuiper-belt science," said Jennings. "Goddard has supplied infrared spectrometers for many missions, including Voyager, COBE, Cassini and EO-1. SwRI has a strong background in space-borne ultraviolet experiments, and is supplying Alice for the Rosetta mission. Ball has a long and highly successful record of building a variety of space instruments."
The instrument package was developed, lab and flight tested over a period of eight years, beginning with NASA "Advanced Technology Insertion" funds specifically targeted at the advanced sensor and miniaturization needs of a Pluto mission.
In addition to SwRI, Ball, and Goddard, the New Horizons team includes The Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md., NASA's Jet Propulsion Laboratory (JPL), Pasadena, Calif., and a variety of other universities and research institutions. APL will manage the mission for NASA and design, build and operate the New Horizons spacecraft. JPL will provide navigation support, and tracking and communication services through NASA's Deep Space Network. SwRI will lead the science team and guide development of the spacecraft's scientific instruments, while Ball Aerospace and NASA Goddard help develop the payload.