CU’s Laboratory for Atmospheric and Space Physics
By Terri Cook
When the Cassini spacecraft successfully dropped into orbit around Saturn on June 30, 2004, jubilant Boulder scientists celebrated with the public. But at a private barbecue, they raised the roof by mixing a few “Cassini Martinis” made ofSKYY vodka, orange juice and dark-red crème de cassis, garnished with a floating maraschino “planet” encircled by a sliced-orange ring. Although the orbit insertion signified merely the start of Cassini’s primary scientific mission, the team from LASP—the University of Colorado’s Laboratory for Atmospheric and Space Physics—was toasting its 14 years of preparation for that moment.
The day’s euphoria was justified: Cassini’s cutting-edge instruments, one of which was designed, built and operated by LASP, quickly began to transmit spectacular images and startling scientific data, including the discovery of huge saltwater geysers on Saturn’s moon Enceladus. Near the moon’s south pole, Cassini imaged an astonishing series of 1,600-foot-deep “tiger-stripe” fractures that spout dozens of large jets of water. Scientists now believe the geysers come from a subterranean saltwater ocean, making Enceladus a place where primitive life-forms might have evolved.
A decade later, the Cassini-Huygens Mission has twice been extended, and its list of discoveries is as long as your arm. One key instrument is LASP’s $12.5 million UVIS (UltraViolet Imaging Spectrograph), which has revealed the shape and composition of Enceladus’ geysers, given us a detailed look at Saturn’s rings, and penetrated the cloud tops of mysterious Titan, Saturn’s largest moon and the one body in the solar system that many scientists think has a composition very similar to Earth’s during its infancy.
“The best part of my job,” says LASP’s Larry Esposito, UVIS principal investigator, “is being a part of NASA discoveries as they are made, including volcanoes on Venus and Enceladus, and new rings around Saturn.”
Esposito got hooked on astronomy as a boy and has never looked back. “As a kid I taught astronomy at summer camp. As an undergrad, I saw Saturn and its rings through a telescope; it was the most beautiful thing I had seen,” he recalls. “In graduate school, I developed math models of Saturn’s rings. After that, I came directly to LASP, and I’ve been here for 37 years.” Such longevity is not unusual at LASP, and jobs there are highly coveted. “We are always looking for talented scientists and engineers,” Esposito says. “However, competition is stiff for all our openings. We are looking for experience, drive and creativity in new hires.”
Cassini is but one of the nine launched missions in which LASP is currently involved. Founded in 1948—a decade before NASA—LASP is the only space-research institute in the world to have sent instruments to every planet in our solar system, as well as one to Pluto. It has also operated more spacecraft than all the country’s other university-based programs combined, making CU truly the “University of the Universe.”
At LASP these explorations are not limited to professional scientists; the lab includes students in every step of the process, from design and construction of instruments to hardware calibration, software development, analysis of mission data, and even mission operations.
One example of the depth to which students are integrated into LASP projects is the Student Dust Counter (SDC), which is currently riding aboard the New Horizons mission to Pluto. This first-ever exploration of the “dwarf planet” will begin when New Horizons arrives next year. The SDC is the first instrument that was entirely designed, built and tested by students to fly on a NASA planetary mission. Keen CU students will continue to operate it for at least another decade as it probes the Kuiper Belt, a region of small, icy bodies at the edge of the solar system.
Despite the long times between launch and arrival, it’s not hard for LASP staff to maintain their excitement. “There’s always things to do to keep us busy,” says Fran Bagenal, professor of astrophysical and planetary sciences at LASP. “In the case of Pluto, as the spacecraft was being built we only knew of one moon around Pluto. Now we know [from Hubble observations] that there are five! This has meant changing our observing strategy.”
The SDC is gathering information on the dust that strikes the spacecraft. Far more important than their small size would suggest, these precious particles provide evidence of and insight into violent cosmic collisions, the formation of our solar system, and extraterrestrial volcanism. Space dust can help scientists answer questions about star and nebula formation and the birth of planets, and dust gathered from the Kuiper Belt will help planetary scientists determine how quickly dust is generated during the frequent collisions between its icy objects.
Mars’ Disappearing Atmosphere
LASP is also leading efforts to explore the inner solar system, including NASA’s recently launched MAVEN (Mars Atmosphere and Volatile Evolution) Mission. Scheduled to arrive at Mars on Sept. 21, 2014, MAVEN will study, among other things, what happened to Mars’ atmosphere, which may once have been dense enough to shield any primitive life-forms that may have evolved from damaging ultraviolet radiation.
As the lead institution for MAVEN, LASP serves as the science operations and data center under the direction of Principal Investigator Bruce Jakosky. LASP is also directing the educational and public-outreach efforts for this mission. LASP also designed and built two of MAVEN’s eight onboard instruments, including the crucial Imaging UltraViolet Spectrometer (IUVS) that will serve as the spacecraft’s “eyes” on the Red Planet’s upper atmosphere.
Today the Martian atmosphere is composed almost entirely of carbon dioxide and has less than 1 percent the thickness of Earth’s, leading to surface temperatures that average about -50°C [-58°F] on its arid surface. But scientists don’t believe Mars has always had a cold and dry climate. Data from other missions show ancient features like channels and deltas that were carved by flowing water, as well as the widespread presence of chemical compounds, such as opal, that contain water. The difference is crucial because if water was present early in Mars’ history, microbes may have been able to survive.
So how and why did the Martian atmosphere change? Scientists speculate this may be due to the loss of volatile gases, such as carbon dioxide and water, to space, and that this loss could be the key to explaining Mars’ dramatic climate change over the last 4 billion years. MAVEN will analyze the upper atmosphere’s composition and structure, determine the current rate at which gases are escaping, and calculate the amount of gas the Red Planet has lost over time to determine whether such leakage is responsible for its disappearing atmosphere.
Searching for Goldilocks
LASP also manages Mission Operations for the Kepler Mission, a space-based telescope orbiting the sun. It was designed to scan a nearby portion of the Milky Way galaxy for “Goldilocks” planets: Earth-size planets in or near the “just-right” habitable zone where life-giving liquid water may be found.
Kepler uses a photometer, an instrument that measures subtle variations in brightness, to detect a dimming of starlight when a planet passes in front of its star. The spacecraft’s ability to measure variations in the brightness of more than 100,000 stars every half hour has shown us that planets are a dime a dozen in the galaxy, Earth-size planets are common, and hundreds of star systems host multiple planets. Kepler also discovered a new type of planetary system, like Star Wars’ Tatooine, where planets orbit multiple suns.
In February, NASA excitedly announced a Kepler bonanza: the discovery of 715 new planets, four of which are less than 2.5 times the size of Earth and orbit in their sun’s habitable zone. This brings the confirmed number of planets outside our solar system to nearly 1,700. The implications of these discoveries are staggering. Astronomers detected the first planet outside our solar system just over 20 years ago, but they now estimate there could be as many as 40 billion habitable Earth-size planets in the Milky Way alone.
Unfortunately in August a faulty reaction wheel, which controls Kepler’s orientation, ended the initial mission. Resourceful scientists have since devised a method by which they can continue to use Kepler, and NASA approved their second-generation proposal in May. Meanwhile, astronomers are poring over a huge backlog of Kepler data, with many more discoveries likely to come.
LASP’s future remains bright. MAVEN will arrive at Mars this fall, New Horizons at Pluto in 2015, and two years later Cassini will hurtle very close to Saturn’s rings, offering scientists an up-close look the likes of which has never been seen before.
“We are lucky to work in an area of exploration that keeps finding interesting new things—surprises turning up around the next corner,” Bagenal says. With current missions extending into the next decade, and its scientists and students already hard at work developing eight future missions, LASP is sure to keep celebrating and reaching for the stars.
Terri Cook is a Boulder-based science writer who vividly remembers the first time she saw Saturn’s beautiful rings. Temporarily living in Australia, she searches for the Southern Cross constellation each night. She is the co-author of three books, including Geology Underfoot Along Colorado’s Front Range.