To Pluto and beyond: UAF space scientist looks to solar system's edges

January 29, 2014

Diana Campbell
907-474-5229
1/27/14

In the outer reaches of our solar system, a NASA spacecraft is moving toward a 2015 rendezvous with Pluto.

The spacecraft launched in 2006, and by the time it gets to Pluto, it will have traveled over 3 billion miles, a trip that would have taken a jetliner 700 years.

Called New Horizons, its mission is to get a better understanding of Pluto and its moons, and to look at the Kuiper Belt, the rocky swath of ice worlds that encompass our solar system. It will provide the first close look at Pluto and its many moons.

Scientists plan to map geology and surface composition, take high-resolution images, assay Pluto’s atmosphere and measure temperatures of Pluto and other objects in the Kuiper Belt. They hope the findings will provide insight into the origin of the solar system.

It is a mission of discovery, noted Peter Delamere, a space physicist at the University of Alaska Fairbanks Geophysical Institute and a long-time New Horizon mission science collaborator. The Pluto encounter begins at the end of this year and the craft will closely pass by Pluto in July 2015 before moving deeper into the Kuiper Belt. Delamere specifically wants to know how the solar wind flows around Pluto and engages with its expanded atmosphere. He spent three years developing a model of the solar wind and atmosphere interaction, which was used in part of mission planning before the 2006 New Horizons launch from the Kennedy Space Center.

“It will take nine years to get there, but careful initial planning for the encounter was essential,” Delamere said.

Solar wind and atmospheres

Solar wind is caused from eruptions from the sun, or solar flares, which then send waves of charged gas, called plasma, into space. The winds travel at 400-600 kilometers per second, moving around objects they encounter.

Some planets, including Earth, have a magnetic field around them. The field affects a region, called the magnetosphere, around the planet. Delamere studies what happens when the solar wind meets the magnetosphere.

KENNEDY SPACE CENTER, FLA. — Into a cloud-scattered blue sky, NASA’s New Horizons spacecraft roars off the launch pad in 2006 aboard an Atlas V rocket spewing flames and smoke. Liftoff was from Complex 41 on Cape Canaveral Air Force Station in Florida. It was the third launch attempt in as many days after scrubs due to weather concerns. The compact, 1,050-pound piano-sized probe got a boost from a kick-stage solid propellant motor for its journey to Pluto. New Horizons was the fastest spacecraft ever launched at that time, reaching lunar orbit distance in just nine hours and passing Jupiter 13 months later.

Pluto is not expected to have a magnetic field. It has an extended atmosphere, rich in nitrogen, methane and carbon monoxide, that may behave like Earth’s primordial atmosphere. How the solar wind interacts with Pluto’s atmosphere was the subject of Delamere’s three-year study before the mission.

Pluto is interesting, but Jupiter is really cool.
Pluto and the Kuiper Belt is the focus of New Horizon’s mission, but it’s most astounding discovery so far was made when the craft flew by Jupiter, said Alan Stern, the project’s principal investigator.

When the solar wind blows around an object, a tail is created on the backside. This is called a magnetotail. Scientists believed Jupiter's magnetotail had layers and structure, based on what is known about Earth’s.

The New Horizons spacecraft had to launch in January 2006 in order to reach Jupiter for a gravitational fling toward Pluto the next year. The spacecraft flew directly down the middle of Jupiter’s magnetotail and gave scientists the first look inside one.

Instead of a simple layered structure, New Horizons indicated Jupiter’s magnetotail had “blobs” of plasma, sort of like a lava lamp.

“It was the groundbreaking discovery about Jupiter,” Stern said. “This was the single headliner. Peter played a significant role in the interpretation.”

The spacecraft is a breakthrough in low-cost planetary exploration, he said. The price of the 10-year mission, about $700 million, amounts to $2.50 for each person in the United States. Mission planners were careful in selection of measurement instruments and mission objectives. However, the craft does not have a magnetometer, something that would have measured the strength of the magnetism in the magnetosphere. Delamere and others have to rely on New Horizons’ measurement of magnetic direction only.

“It hurts,” he said. “But it was justifiable.”

Peter Delamere, a space physicist with UAF's Geophysical Institute, has a Jupiter/Pluto connection.

Looking up

It’s a space scientist’s job to look up into the sky and wonder, Delamere said. Alaska’s auroras led him to study Jupiter and now Pluto. Jupiter has auroras that are likely caused by gas and plasma flowing from Io, Jupiter’s volcano-peppered moon, he said.

Recently, he and his family visited Mauna Loa in Hawaii, the world’s largest volcano. While looking at the landscape, Delamere couldn’t help but wonder whether a view on Io would be similar.

“If the sky was orange instead of blue, maybe,” he said.

ON THE WEB:
www.scienceforalaska.com
pluto.jhuapl.edu