NEW HORIZON'S LONG JOURNEY
It has been more than nine years and 3 billion miles since the spacecraft launched in early 2006.
Pluto’s new moons in sight
This is the first mission to Pluto and the Kuiper Belt, a gigantic zone of icy bodies and
mysterious small objects orbiting beyond Neptune. It marks the first direct exploration of this zone of our solar system, beyond the inner rocky planets and outer gas giants.
While still 55 million miles from Pluto, the long-range imager showed the largest known moon, Charon, plus smaller moons Nix and Hydra. New Horizons also saw, for the first time, the tiny moons of Kerberos and Styx, originally discovered in 2011 by the Hubble Space Telescope.
The New Horizons craft was designed at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md. When it reaches Pluto on July 14, it will take almost 4½ hours for a radio signal to travel from it to the mission operations center at APL.
THE ROUTE TO PLUTO AND BEYOND
In February 2007, New Horizons took advantage of a gravity-assist slingshot from Jupiter, speeding New Horizons up to more than 51,000 mph.
JAM-PACKED WITH SCIENTIFIC EXPERIMENTS
Long Range Reconnaissance Imager (LORRI)
LORRI is the highest resolution instrument on board. At Pluto, LORRI will take images in which football-ﬁeld-sized features will be visible.
The star trackers are dual cameras used to compare the observed star ﬁelds against an on-board database of more than 18,000 star patterns.
Solar Wind At Pluto (SWAP)
The SWAP instrument will measure charged particles from the solar wind near Pluto to determine how fast its atmosphere is escaping.
Student Dust Counter (SDC)
The SDC, which was designed, built and operated by students at the University of Colorado, faces in the direction of spacecraft travel so it is exposed to dust particle impacts.
Reaction Control Jets
The New Horizons spacecraft controls its attitude in space through the use of short bursts from these small thrusters arrayed around the vehicle. New Horizons will only be able to alter its course by less than 2 degrees at Pluto.
This tank, made of titanium and nestled in the center of the spacecraft where it can be kept warm, carries enough liquid hydrazine to supply the reaction control jets for the entire 15+ year duration of the New Horizons mission.
Low Gain Antenna 1 (LGA)
Sitting just above the propellant tank is one of two LGAs, which provided communications with Earth during launch and early operations.
Alice is an ultraviolet imaging
spectrometer that separates light into its constituent wavelengths and will probe the atmospheric composition of Pluto.
As the spacecraft passes behind Pluto, with respect to Earth it will precisely measure how incoming radio signals are affected by the thin Pluto atmosphere.
Pluto Energetic Particle Spectrometer Science Investigation (PEPSSI)
PEPSSI is a plasma-sensing instrument that
will search for neutral atoms that escape Pluto's atmosphere and subsequently become charged by their interaction with the solar wind.
High Gain Antenna (HGA)
The HGA main dish collects incoming signals but also forms outgoing signals.
The feedhorn directs the radio signals in and out of the spacecraft.
Pluto is so far from the sun that power production with solar cells is impractical, so New Horizons uses a decaying radioisotope as a battery to produce about 200 watts of electrical power for the spacecraft and its instrument payload at Pluto.
Medium Gain Antenna (MGA) and HGA
The Earth-facing side of the dish redirects incoming and outgoing signals to and from the MGA on the spacecraft-facing side.
For maximum data rate, the HGA must be kept pointing toward Earth. If the spacecraft loses track of its attitude, this sun sensor will allow the spacecraft to regain a sun-pointing orientation and receive commands from Earth.
Using a single telescope with a 3-inch aperture, this compound instrument collects many wavelengths of light to obtain high-resolution surface composition maps of the surfaces of Pluto and its moons both in visual and infrared.
Weight and size of New Horizons
The spacecraft weighed a mere 1,054 pounds at launch (about as much as a couple of snowmobiles).
Aside from the communication dishes and the radioisotope battery tube, the whole framework is about the size of a grand piano.
SOME VERY BUSY HOURS NEAR PLUTO
At its closest point New Horizons will be less than 8,000 miles from the dwarf planet’s surface and about 17,900 miles from the largest moon, Charon.
If all goes as planned at precisely 07:49:58 EDT on July 14, New Horizons, traveling at more than eight miles per second, will be at its closest point to Pluto.
APL scientists may yet decide to redirect the craft farther out from the system if there is a strong possibility of impacting debris.