First Pluto ‘family photo’ released, NYC Explorers Club holds ‘Plutopalooza’
With just two months remaining until New Horizons’ July 14, 2015, Pluto flyby, the mission team released a complete Pluto “family photo” featuring the entire system with its five known moons. With the spacecraft speeding toward its primary target before continuing on its way to other potential targets located within the Kuiper Belt, the mission is starting to provide humanity its first glimpse of these distant, frozen worlds.
The spacecraft’s Long Range Reconnaissance Imager (LORRI) imaged the Pluto system from a distance of approximately 55 million miles between April 25 and May 1. Each observation consisted of five ten-second exposures.
Once returned to Earth, the images were heavily processed to remove the glare of background stars as well as that of Pluto and Charon, all of which wash out the smaller objects.
The images were then added together to create a “family photo” depicting Pluto and its known moons along with an animation of their orbits.
In New York City, growing anticipation of the flyby was evident among the approximately 120 people who attended a Plutopalooza at the Explorer’s Club on May 13, featuring four members of the New Horizons team who discussed the mission and gave a preview of what to expect in the next few months.
The speakers were Alan Stern, principal investigator of the New Horizons mission; Cathy Olkin, New Horizons deputy project scientist and member of the Pluto Encounter Planning Team; Marc Buie, a New Horizons co-investigator; and Tiffany Finley, principal engineer and member of the Space Operations Team.
Buie was a founding member of an unofficial group known as the “Pluto Underground”, which advocated a mission to Pluto since the Voyager 2 Neptune flyby in 1989.
Finley, as a graduate student, helped build, design, and test the Venetia Burney Student Dust Counter (VBSDC) currently aboard New Horizons and the only student-built instrument on a major NASA mission.
The event began with a video celebrating 85 years of human knowledge about Pluto, beginning with the planet’s 1930 discovery by 24-year-old Clyde Tombaugh.
“This is the fastest mission ever launched, going the farthest that any mission ever has, to make a reconnaissance of a new world, way out in the Kuiper Belt, the third zone of the Solar System,” Stern said.
It took 15 years to design, build, test, and launch, with a total cost of $700 million.
The Kuiper Belt consists not just of small objects but also of small planets, Stern said, showing a scale image of the many objects in the region that are large enough to be spherical.
“The actual estimate is when we’re done [exploring], we will discover hundreds of planets in the Kuiper Belt. This is really a revolution in planetary science.”
This new zone of the Solar System “was just begging for exploration”.
Using a New Horizons model about one-eighth the size of the actual spacecraft, he demonstrated its seven instruments and their functions, comparing them to those on Voyager 2, the most recent spacecraft to first visit a planet. Whereas Voyager’s infrared camera had only one pixel, its counterpart on New Horizons has 64,000. New Horizons’ instruments are miniaturized but far more sophisticated than Voyager’s.
The best image of Pluto, which was taken by Hubble, shows only fuzzy dark and bright regions, but no details providing any information about the planet’s surface and composition.
That is about to drastically change. To emphasize the detail New Horizons will resolve on Pluto, Stern showed an image of New York City from which viewers could easily pick out Brooklyn and Manhattan, the Hudson and East rivers, and the ponds in Central Park, noting this is what New Horizons would see if it flew over Earth and photographed it at the same resolution being used at Pluto.
New Horizons’ instruments will conduct composition spectroscopy, atmospheric spectroscopy, in situ measurements of gases coming off the atmosphere and many other types of science.
“We are so looking forward to discovering what’s there. This is raw exploration,” Stern emphasized.
In her presentation, Finley noted the Student Dust Counter did not spend time in hibernation like the other instruments on the spacecraft, but it has been doing science during the entire nine years of the mission.
Data sent back by the SDC is analyzed by students, she added. No measurements of dust in the Solar System have been conducted beyond 18 astronomical units (AU) from the Sun. One AU equals approximately 93 million miles, the average distance between the Sun and the Earth. SDC is now measuring dust at 40 AU, Finley noted.
SDC was entirely student designed, built, and tested. Because it is located on the outside of the spacecraft, it has to endure extreme cold temperatures. To ensure it would survive, students dumped the detector in liquid nitrogen, then tested it afterwards to see if it still functioned. It did.
The students who built SDC were subject to the same NASA review panels faced by professional instrument-building teams.
Buie spent 17 years working at Lowell Observatory, where Pluto was first discovered. Using data obtained from Hubble, he created the first map of Pluto’s surface, the fuzzy image showing alternating bright and dark spots, representing the colors people would actually see if they were to fly close to the planet.
“What we see here is lots of bright patterns and dark patterns that repeat. We’ve known about these for years,” he said, noting one of the bright regions is abundant in carbon monoxide ice. He also said that most of the surface is known to contain methane and nitrogen ice, while the darker areas are believed to have a high carbon content.
Buie suspects the dark patches are the oldest surface regions and the bright areas the youngest. The bright areas are rich in nitrogen frost, which is sublimating off the atmosphere and racing around the planet.
At half the size of Pluto, Charon is a planet in its own right, he said.
The arrangement and origin of the whole system with its five moons is puzzling. “Getting it there with this assemblage of satellites is hard to do,” Buie stressed, adding he believes New Horizons will find additional moons.
Kerberos was discovered in 2011 and Styx in 2012, both by members of the New Horizons team using Hubble to search for potential hazards to the spacecraft. Styx is estimated to be between four and 13 miles in diameter. Located between the orbits of Nix and Charon, it revolves around Pluto once every 20 days. Kerberos, with an estimated diameter between six and 20 miles, sits between the orbits of Nix and Hydra, orbiting Pluto every 32 days. Both are 20 to 30 times fainter than Nix and Hydra.
Olkin said that New Horizons has the same amount of data storage as an iPhone – eight gigabytes. Data is collected, sent back to Earth, then erased so more data can be collected.
Olkin illustrated the trajectory the spacecraft will take as it flies through the system.
May 11 began what mission team members call “seven weeks of suspense”, during which the mission team will actively search for all possible hazards that could pose a threat to the spacecraft.
If any are found, the team will have to choose between two options – using the antenna as a shield or changing course to one of three alternate trajectories. If the latter is deemed necessary, an engine burn will be conducted two weeks before the flyby date.
Meanwhile, more data is being sent back between May 14 and 28, so new images are likely to be released during this period. Raw, unprocessed images are posted at the New Horizons image site within 48 hours after being received.
Beginning May 28, the spacecraft will start taking full resolution images of both Pluto and Charon.
Laurel Kornfeld is an amateur astronomer and freelance writer from Highland Park, NJ, who enjoys writing about astronomy and planetary science. She studied journalism at Douglass College, Rutgers University, and earned a Graduate Certificate of Science from Swinburne University’s Astronomy Online program. Her writings have been published online in The Atlantic, Astronomy magazine’s guest blog section, the UK Space Conference, the 2009 IAU General Assembly newspaper, The Space Reporter, and newsletters of various astronomy clubs. She is a member of the Cranford, NJ-based Amateur Astronomers, Inc. Especially interested in the outer solar system, Laurel gave a brief presentation at the 2008 Great Planet Debate held at the Johns Hopkins University Applied Physics Lab in Laurel, MD.