Public event at CU to mark Pluto fly-by

BOULDER — The University of Colorado Boulder will host a free public event at Fiske Planetarium Tuesday evening to mark the New Horizon spacecraft’s closest approach to Pluto.

The three-hour event, beginning at 5 p.m., will include the showing of a new documentary, “The Year of Pluto,” followed by live feeds from NASA headquarters and a live panel discussion. The planetarium is located at 2414 Regent Drive on the CU-Boulder campus.

A team of CU-Boulder students designed, built and tested the Student Dust Counter for the mission to measure dust particles along the way that are remnants of collisions between solar-system bodies. The device is the first student-built, student-operated instrument ever to fly on a NASA planetary mission, and the only one of the seven instruments aboard New Horizon that has been collecting data since its launch.

The closest point of New Horizon’s fly-by will occur at 5:49 a.m. Tuesday, and the craft is expected to “phone home” between 7 and 8 p.m. with the first up-close images of the tiny world at the edge of our solar system, said CU spokesman Jim Scott.

Scott was at Johns Hopkins University’s Applied Physics Laboratory in Baltimore today along with other CU-Boulder scientists and students involved in New Horizons for the Pluto encounter. APL designed, built and operates the mission and manages it for NASA.

The fly-by will culminate a nine-year, 3 billion-mile journey for New Horizon, a piano-sized, power-packed spacecraft.

“We have waited a long time for this,” said CU-Boulder physics professor Mihaly Horanyi of the Laboratory for Atmospheric and Space Physics and a New Horizons co-investigator. From 2002 to 2005, Horanyi shepherded a revolving group of about 20 students as they developed the dust counter, which is helping researchers learn more about the origin and evolution of our solar system and the formation of planets from dusty disks around other stars.

The dust counter is a thin plastic film resting on a honeycombed aluminum structure the size of a cake pan mounted on the spacecraft’s exterior. A small electronic box inside the spacecraft functions as the instrument’s “brain” to assess each individual dust particle that strikes the detector. The tiny dust grains hitting the dust counter create unique electrical signals, allowing the students to infer the mass of each particle.

“This mission will complete the first reconnaissance of our solar system and will reshape our understanding of the region where Pluto resides,” said CU-Boulder doctoral student Marcus Piquette, a member of the SDC science team, in a media statement issued by CU.

CU-Boulder professor Fran Bagenal, a mission co-investigator who leads the New Horizons Particles and Plasma Team, was a member of the original “Pluto Underground” — a small, dogged band of planetary scientists who began lobbying NASA in 1989 for a Pluto mission. The Pluto Underground also included then-CU-Boulder doctoral student Alan Stern, who now leads the New Horizons mission from the Southwest Research Institute’s Planetary Science Directorate in Boulder.

Bagenal, a faculty member in the Department of Astrophysical and Planetary Sciences and LASP affiliate, said the interactions of the solar wind with Pluto’s tenuous atmosphere, which is leaking into space, is of high interest.

“It’s clear that when Pluto’s orbit takes it closer to the sun, like it is today, the atmosphere is escaping like crazy,” she said.

Scientists don’t yet know what happens to Pluto’s atmosphere when the dwarf planet moves further from the sun, since a single solar orbit takes 248 years.

Bagenal and her colleagues also want to learn more about why Pluto and some other objects in the Kuiper Belt — a region spanning more than a billion miles past Neptune’s orbit and believed to harbor thousands of moon-sized objects and billions of comets — seem to have a reddish hue.

“It could be that energetic solar particles and cosmic rays are causing chemical reactions on the planet’s surface, turning the methane ice on Pluto’s surface to a reddish-brown gunk,” she said.

In addition to the dust counter, New Horizons is carrying two cameras, two imaging spectrometers and two particle spectrometers to gather data on the surfaces, atmospheres and temperatures of Pluto, its five moons and several Kuiper Belt objects.

“We really have little sense of what Pluto looks like,” Bagenal said. “But with New Horizons we will get our first detailed glimpse of the surface. We will see whether there are craters, or volcanoes, or frost, or tectonic cracks — or something totally unexpected. I think we are in for a good ride, and it’s going to be lots of fun.”

“The fly-by also is an emotional capstone for all the students who worked on SDC,” Horanyi said. “They have moved on to have families and kids and busy lives, but I know that all of them will closely follow the encounter, and remember their contributions with tremendous pride. The encounter is a landmark event along the way to explore the outskirts of the solar system, even beyond Pluto, for possibly decades to come.”