“Can any of you tell
Where Pluto here may dwell,
For we, sirs, are two strangers who were never here before?”
Aristophanes — “The Frogs” (405 B.C.E)
In Aristophanes’ comedy “The Frogs,” the ancient Greek comic playwright narrated the adventures of the god Dionysus who journeyed to the Underworld to bring the critically acclaimed tragic poet Euripides back to life, in the hopes of re-instating the desperate state of affairs of Athens’ theatrical plays back to their former glory. In the real world, NASA’s “New Horizons” spacecraft is traversing interplanetary space to unveil new and profound knowledge about the dwarf-planet named after the mythological Greek god of the Underworld.
Having been launched eight years ago this week, on Jan. 19, 2006, “New Horizons” is well into the late-cruise phase of its mission, hurtling through the Solar System to conduct the first ever fly by in human history of Pluto and its moons. A secondary objective is the reconnaissance, if possible, of the vast area lying beyond as well: the frozen realm of minor planetary bodies at the very edges of our Solar System, better known as the Kuiper Belt.
The “New Horizons” mission is the culmination of decades worth of efforts by NASA and the planetary science community to explore this last unknown territory of the Solar System. Going back to the days of the Voyager Grand Tour of the 1970s and ’80s, scientists and engineers had briefly considered at the time sending Voyager 1 toward Pluto following the Saturn Encounter in 1980. Doing so would mean putting the spacecraft toward a trajectory that would prohibit a close examination of Titan, and Saturn’s largest and more intriguing moon was eventually chosen instead as a more interesting scientific target. As Pluto approached perihelion in 1989, many proposals calling for a dedicated mission to the then ninth planet were sent to NASA, with none of them ever advancing beyond the mission concept phase. One of them, the Pluto Kuiper Express, held much potential of being realised in the 1990s, but the space agency eventually cancelled the mission in 2000, reacting to a series of cost overruns and budget cuts imposed by the White House at the time. An intense reaction and a coordinated lobbying campaign by the planetary science community on Congress led to the Senate re-authorising NASA to continue with a Pluto-dedicated mission. It was out of this campaigning effort that New Horizons arose, as the first of a New Frontiers-class of missions, with a cost of $650 million throughout its operational cycle.
Following a successful launch onboard an Atlas V rocket in 2006, and a crucial Jupiter fly by in 2007 that yielded some important science, the New Horizons spacecraft, with the exception of a few brief periods of activity, has spent most of its time since in hibernation, quietly passing the orbits of the outer planets en route toward its final destination. Yet, as is the case with another deep-space mission that currently roams the Solar System, the turn of the calendar year brought an end to the New Horizons’ long slumber.
The Johns Hopkins Applied Physics Lab in Laurel, Md., which is managing New Horizons, activated the spacecraft once again on Jan. 5 to check on the overall health of its systems and prepare it for the Pluto encounter operations that begin in January 2015. “We’ve had busier wakeup periods, but with long-distance Pluto encounter operations starting only a year from now, every activity is important,” says Alice Bowman, mission operations manager for New Horizons at the Johns Hopkins Applied Physics Lab. Wake-up activities included checking on the spacecraft’s High-Gain Antenna, uploading of new commands to the onboard computer, and updating of the onboard star charts used for navigation.
Update and calibration of New Horizons’ navigation star charts are crucial parts of the pre-encounter activities, so that the spacecraft is kept on the correct path toward Pluto while adjusting for any trajectory errors that could otherwise lead it off course. Beginning this month, one of the mission’s scientific instruments, the Long Range Reconnaissance Imager, or LORRI, will initiate an imaging campaign by detecting the dwarf planet’s position against the background stars and start taking photographs that will help mission managers on the ground to keep New Horizons on track for its rendezvous with Pluto in July 2015. “LORRI will photograph the planet against known background star fields,” says Alan Stern, associate vice president of the Southwest Research Institute’s Planetary Science Directorate in Boulder, Colo., and principal investigator for the New Horizons mission. “We’ll use the images to refine Pluto’s distance from the spacecraft, and then fire the engines to make any necessary corrections.”
But that will not be all for New Horizons during 2014. The spacecraft will be awakened again during the summer for more imaging activities with LORRI and will also carry out these correction maneuvers, based on the instrument’s data. The scientists will also go through a full series of testing of the onboard backup systems and science instruments to check that everything is nominal before long-distance science operations begin in January of next year. After that, it will be sleep time again for New Horizons, until the spacecraft is awakened again in December to stay active for the remainder of its mission through the Pluto-Charon system and beyond.
Besides LORRI, New Horizons is equipped with a full set of six science instruments. These include a visible/infrared imaging spectrometer named “Ralph,” a similar instrument for ultraviolet wavelengths named “Alice,” a solar wind and plasma spectrometer called “SWAP,” an energetic particle spectrometer called “PEPSSI,” a passive radiometer for measuring atmospheric composition and temperature called “REX,” and a Student Dust Counter, or “SDC.”
This scientific payload will help provide humanity with its first-ever close-up images and data of the Solar System’s last unexplored frontier. While the New Horizons spacecraft will fly through the Plutonian system at 36,373 mph (58,536 km/h), it will beam back photographs of vistas never before seen from the surfaces of Pluto and its moons Charon, Nix, Hydra, Kerberos, and Styx. “Everything we see on Pluto will be a revelation,” comments Stern. “There is a real possibility that New Horizons will discover new moons and rings as well.”
Coincidentally, New Horizons’ arrival at Pluto in July 2015 will mark the 50th anniversary of the first-ever planetary imaging fly by in the history of space exploration— Mariner 4′s fly by of Mars in July 1965. “The future has finally arrived,” said Stern in early January following the re-awakening of the New Horizons spacecraft from its hibernation. “After all the time and miles in the rearview mirror, the turning of the calendar page last week to 2014, means we’ll be exploring the Pluto system next year!”
The results from the mission promise to be as groundbreaking and revolutionary as those from Mariner 4—the first mission to open our eyes to the beauty, awe, and wonder of the Solar System, five decades ago. What a better way to celebrate this 50th anniversary than with the first-ever close-up images of Pluto!