The New Horizons Mission to Pluto
What is the atmosphere of Pluto made of, and how does it behave? What does the surface of Pluto look like? What causes those colors? Are there interesting and unique geological features? How do particles in the solar wind interact with Pluto’s atmosphere? These are but some of the questions NASA scientists hope to answer during the coming flyby in 2015.
On January 19, 2006, NASA launched the New Horizons spacecraft for a dramatic flight past icy dwarf planet Pluto and its moons two years from now in July 2015. After a 10 year and more than 3 billion mile journey, New Horizons will reveal information about worlds on the edge of the solar system. Plans for the mission include flybys of one or two Kuiper Belt Objects. These icy bodies are found orbiting the Sun in a zone beyond the orbit of Pluto. They range from about 25 to 55 miles (40 to 90 kilometers) in diameter.
The objects in the Kuiper Belt are presumed to be remnants from the formation of the solar system about 4.6 billion years ago. The Kuiper Belt probably contains hundreds of thousands of icy bodies larger than 100 km (62 miles) across and a trillion or more comets. Some of these pass near Earth. One will pass very near the Sun in late 2013. It is hoped that it will give us an exceptional show.
New Horizons is packed with seven instruments selected to meet the mission’s science goals. Follow the link for details about each one.
Where is New Horizons Now?
The spacecraft is more than halfway between the orbits of Uranus and Neptune. This image is copied from a site which plots the position hourly. Follow this link for the most current position plotted on that site. Because the distances are so large, no significant changes in the plot can be seen unless weeks have passed. It looks like the spacecraft is near Pluto. But, it will take another two years for it to reach Pluto.
The Kuiper Belt and KBO
Arrival at Pluto is approaching with great anticipation. But, that will not be the end of the mission. The spacecraft will continue to coast from the Sun into a region called the Kuiper Belt. The asteroid belt is mostly metal and rock. The Kuiper Belt is made mostly of icy chunks of various substances. Kuiper Belt Objects KBO have similar composition to comets. They are a made of combinations of frozen water, ammonia and hydrocarbons, such as methane. Occasionally, the KBO objects collide or attract each other gravitationally and divert their paths. One of them might then be on a new path toward the Sun and produce a comet for us to see.
Pluto is one of the largest known KBOs. There are a number of other objects of substantial size. Quaoar is more than half the size of Pluto, and Makemake and Haumea are much closer in size to Pluto. A number of KBOs, including Pluto and Haumea, also have moons of their own.
After passing Pluto and Charon, the spacecraft can change course slightly for a flyby of a KBO. The KBO target will not be selected until shortly before the Pluto encounter. It will be similar to the Pluto-Charon encounter. Scientists will map the KBO with high resolution images, measure its surface and atmosphere compositions, and look for evidence of craters and moons. To find the potential icy KBO targets, thousands of ground based images were analyzed. They were taken specially for this purpose using ground based telescopes. These images contained undiscovered slow-moving Kuiper Belt Objects, asteroids moving through the foreground, and millions of background stars.
I participated in the search of these images during 2011 as a citizen scientist at a web site called Zooniverse. The IceHunters project was one of several citizen science projects available at Zooniverse. Dr. Pamela Gay and Corey Lehan of Southern Illinois University produced an easy to use and effective interface for searching for and identifying potential KBO candidates. The KBO IceHunters search project is no longer operational.
What is the Science in the Image Analysis?
The images were taken by the 8-meter Subaru telescope on Mauna Kea, or the 6.5-meter Magellan telescope in Chile. The same star regions were imaged a few days or weeks apart. The images were balanced for brightness and contrast. Then the images were overlaid and subtracted. Objects which don’t move like stars will effectively disappear. Objects which do move will appear in different locations. What is left in the final product is an image with most bright stars subtracted out of the blotchy field. But there are some asteroids, KBOs, and variable stars still clearly present. Those were viewed and marked by the large number of volunteers in the Zooniverse membership.
For example, here is a potential KBO marked with a circle.
Here is likely an asteroid noted by the 3 fuzzy dots in a row below center when 3 images were subtracted. Most of these asteroids were known. Some were newly discovered by the IceHunters volunteers. They received credit as an official discoverer of the new asteroid.
Please Join the Zooniverse Citizen Scientists Projects
Sign up and take part in one of the interesting projects available at Zooniverse. Join the nearly 850,000 people worldwide. Citizen science is a lot of fun and can help advance the research more quickly due to the large numbers of volunteers. There are now seventeen projects in areas of space, climate, nature, humanities, and biology.