Space: the final frontier.
Last Friday, Hap McSween, Ph.D. and a UT Chancellor's professor of Earth and Planetary Sciences, held a presentation on NASA's current goal to explore Mars' moons.
Titled "Exploring the Asteroid Vesta: NASA's Dawn Mission," McSween outlined details of the spacecraft's mission at this week's Science Forum, held in Thompson-Boling Arena.
According to NASA's Dawn Mission website, the objective "is to characterize the conditions and processes of the solar system's earliest epoch by investigating in detail two of the largest protoplanets remaining intact since their formations. Ceres and Vesta reside in the extensive zone between Mars and Jupiter together with many other smaller bodies, called the asteroid belt."
McSween presented a timetable chronicling important past and future dates for the spacecraft, as well as the current mission status.
"The Dawn spacecraft has completed its orbital investigation of asteroid Vesta and is now en route to asteroid Ceres," McSween said in a press release. "These are the two most massive asteroids, and their properties provide an interesting view of the diversity of planetary building blocks."
McSween provided the schematics of spacecraft, listing the different instruments on board and their purpose. During Dawn's approach to Vesta, NASA utilized the instruments to full effect, gathering data regarding the asteroid.
One particular instrument onboard the spacecraft, called the Visual and Infrared Spectrometer (VIR), maps the surface of the asteroids with a spectrometer.
This allows Dawn to examine the reflected light intensity in select wavelength bands, which is used to determine chemical composition, property and temperature.
"As we approached Vesta, we had Dawn use the VIR to sample sunlight from numerous points on the surface," McSween said Friday during his lecture. "We then compared it to the spectrum measured in the laboratory of diogenite, eucrite and howardite – three types of meteorites that we have from Vesta. We found that the average surface of VESTA appears to be made of howardite, which is made of a unique chemical composition that is characteristic of asteroids."
Another gadget, called Gamma Ray and Neutron Detector (GRaND), measures the abundances of several key rock-formation elements, including Oxygen, Aluminum and Magnesium. By analyzing how much of each element is present, rough estimates of the composition of the different regions on the asteroids can be created. The instrument, however, provided a surprise to the NASA scientists.
"We used GRaND to gather data to supplement what we gathered from prior findings, but GRaND can also measure another element – hydrogen," McSween said. "We expected to see no hydrogen on Vesta, but lo and behold, we made a map that showed areas with high amounts of hydrogen, in the form of water, and it was a big surprise.
"We also found a different type of meteorite, called Carbonaceous chondrites, which contains water. This is important because it tells us about the possibility of delivery of water to our own planet early in its history."
Students and faculty each left with new views and thoughts on the work required to pull off the Dawn mission.
"I thought the presentation was excellent," said Tom Kosidowski, a sophomore at Tusculum College. "I heard about the forum online, and was curious enough to come and see what it was about. It gave a lot of amazing information about the asteroid Vesta, its mineral makeup, and composition.
"I particularly like the analogy of the work required of the engineers – it's like having to hit a hole-in-one from Knoxville to California while California was moving. It really shed some insight as to just how intelligent and brilliant these engineers working for NASA are."
Mark Littmann, the program chairman of the UT Science Forum and professor of journalism and electronic media, said he hopes the presentation will stimulate students to attend more forums and work with a renewed vigor.
"It's amazing how much progress has been made, especially in astronomy," Littmann said. "To meet Dr. McSween and hear him present this ingenious work and new information about a world so different that we cannot imagine what it looks like – I hope it will motivate students to get more involved with the forum and plan projects as grand as this."
The UT science forum meets every Friday, in Thompson-Boling Arena Café, from noon to 1 p.m.