NASA’s New Horizons probe is en route for the outer solar system. After scoring a spectacular flyby of Jupiter and its moons in 2007, the craft is now heading for Pluto and beyond. It will be the first probe to reach Pluto, a goal which has been delayed by repeated budget cuts. After that, it will be the first to make a close approach to a Kuiper Belt object.
The Jupiter flyby was a huge success, allowing observations of the giant planet and its moons in unprecedented detail. Among other things, information was gathered about the atmosphere and weather of Jupiter. Data on cloud composition was collected by the visible light, infrared and ultraviolet remote sensing devices, and ammonia was observed welling up from the lower atmosphere to form clouds. Lightning strikes were observed at the poles, the first polar lightning ever seen off Earth, and from this it was learned that heat moves evenly through water clouds at all latitudes across Jupiter. New Horizons also made size and speed measurements of waves in the Jovian atmosphere, indicating strong storm activity beneath, and obtained close-up images of the Little Red Spot, a smaller version of the Great Red Spot. The smaller feature is about half the size of the bigger one, or about 70 per cent of Earth’s diameter.
New Horizons obtained the clearest images yet of the tenuous Jovian rings. Here clumps of material were observed that may be from a recent impact within the ring system. The probe got a detailed view of the ring dynamics involved here, with moons Metis and Adrastea shepherding the materials around the rings. A search for small moons within the rings yielded negative results.
The probe performed observations of Jupiter’s four largest moons, focusing especially on Io, closest to Jupiter and volcanically active. Eleven volcanic plumes of varying size were seen, three for the first time. One of these, a 200-mile-high eruption from the volcano Tvashtar, offered a chance to see the structure and motion of the plume as it condensed and fell back to the surface. Instruments picked up infrared radiation from at least 36 volcanoes on Io with lava temperatures about 1900 degrees Fahrenheit, which is comparable to volcanoes on Earth. Io is the most active body in the solar system, and more than 20 geological changes had occurred since the Galileo Jupiter orbiter was there in 2001. Observations of Io while in Jupiter’s shadow showed glowing clouds over many of the volcanoes, a possible source of gas for Io’s atmosphere.
The probe passed down Jupiter’s magnetotail and got the closest-ever look at this region. Particle detectors indicated that volcanic material from Io moves down the tail in slow-moving blobs. Scientists are hoping to learn how these gases are ionized, trapped and energized by Jupiter’s magnetic field, and then finally ejected from the system.
New Horizons left Cape Canaveral in January, 2006. It is the fastest spacecraft ever built, reaching Jupiter in only 13 months. It is now about halfway between the orbits of Jupiter and Saturn, more than 743 million miles from Earth, and it will fly past Pluto and its moons Charon, Nix and Hydra in July 2015 before going deeper into the Kuiper Belt.
At present, the mission continues to go well. In November of 2009, the probe was brought out of hibernation to repoint the communications dish antenna in order to keep up with the changing position of Earth around the sun. This wake-up also provided an opportunity to download several months of stored data, correct a minor bug in the fault protection system software, perform adjustments to refine the craft’s trajectory, and upload instructions for the running of the craft from now until its next scheduled wake up in January 2010.
While New Horizons will not reach its destination until 2015, it will be able to perform some observations of Pluto and its largest moon, Charon, about a year earlier. It will be taking pictures of the two at that point, and a few months later, it will be able to generate a map of Pluto.
The long approach will give an opportunity to watch seasonal changes in Pluto’s atmosphere. Since 1989, Pluto has been heading away from the sun. In 1999, it crossed the orbit of Neptune, once again becoming the outermost of the nine traditional planets. It is now heading into its 200-year winter, when its atmosphere is expected to freeze and fall to the surface as snow, and because of this, the New Horizons mission will be the last chance to study the atmosphere of Pluto. The probe will obtain information about its chemical composition, and also allow observations of cloud formation. Clouds, probably composed of nitrogen or carbon monoxide, have already been observed in the thin atmosphere of Pluto.
Once New Horizons has passed Pluto, it will head out into the Kuiper Belt to find and study some of the mysterious bodies that exist there, which are thought to be icy and comet-like. The probe will conduct a search for Kuiper Belt bodies, and when it finds them, will modify its own course to approach and observe them. It is hoped that New Horizons will find six to ten of these bodies to study.
The outermost region of the solar system is a vast, dark area that is only beginning to reveal its secrets. What else is out there? Over the next few years, we will begin to find out.
This is great news about the progress of the probe going to Pluto. With so many probes in space it is nice to be informed of the progress of the probe that will give us the answers about the outer solar system and the Kupier belt. Thank you for bringing the video to us.