My deeper exploration of bringing in geospatial data into planetarium software coincided with the release of Dawn’s high resolution maps from Vesta, and as I worked with my colleagues to develop a variety of educational programs on asteroid missions and research, developing an accurate depiction of Vesta in simulation software to bring these results to the public.
In 2014 Dr. Brian Day of NASA Ames, who I had worked with for a lecture on NASA’s LORRI Lunar Orbiter mission, approached me about working together to share the data from Dawn, and other high-resolution planetary mapping missions such as MESSENGER at Mercury and the Mars Reconnaissance Orbiter at Mars with other planetary geologists at the American Geophysical Union conference. Together, with collaborations from NASA JPL and the American Museum of Natural History, we hosted a “dome night” at AGU’s Winter Meeting in San Francisco, where I piloted though simulation software while Brian toured the audience over the incredible geology we were discovering on these worlds.
Binary Asteroids
That same year, I had the opportunity to work with Dr. Franck Marchis of the SETI Institute to visualize his asteroid research. In particular, I created visuals for a lecture he presented on binary asteroids. We first discovered asteroids could have moons when the Galileo mission flew by the asteroid Ida in 1993, photographing its small moon, Dactyl.
Since then we’ve discovered hundreds of asteroids that exist as complex systems: some with a major body and tiny moons, like the largest Trojan asteroid, Hektor.
Others are pairs of similarly sized bodies co-orbiting, like Patroclus and its companion Menoetius–which are now the final targets for the Lucy asteroid mission–which when then discussed only as a future proposal.
While most asteroids are too small to see their shape from Earth, in some cases we have been able to bounce radar off of them during close passes to infer their rough shape. Marchis and colleagues were able to do even better.
Setting up multiple observations of the asteroid Antiope in 2007 and 2008 they were able to observe the system from multiple locations as it passed in front of background stars. These observations provided just enough information to infer the silhouette of the asteroid pair, including a missing chunk of material on one of the components.
Working from these observations, Marchis had me produce a 3D visualization of that asteroid system.
Sample Return Missions
Since the Apollo missions first returned lunar rock samples to the Earth, space agencies around the world have sought to retrieve such samples from more bodies of the Solar System to enhance our understanding of geologic origins of various bodies, and what, if anything, made the Earth the unique abode of life.
The Japanese Space Agency’s (JAXA) Hayabusa mission in the late 2000s caught the attention of many of my colleagues, especially as it revealed in detail the “rubble pile” structure of its small target asteroid, Itokawa.
Subsequent missions provided fresh, evolving opportunities to visualize these ambitious missions, particularly NASA’s OSIRIS-REx mission to Near Earth Asteroid Bennu.
These missions, and future sample returns, will continue to explore the geochemical similarities and differences of the many bodies in our Solar System, and what clues asteroids hold to the unique status of the Earth. Early samples reveal complex organic molecules and elemental abundances similar to Earth.
Large Asteroid Datasets
Asteroids are interesting because in many ways they are time capsules of the early solar system. Earth’s geology has been reshaped by billions of years of plate tectonics, atmospheric weathering, and interactions with the chemical processes of life. Many asteroids, however, are still representative of the raw materials of the early solar system–although they have collided with and battered each other, they haven’t experienced the chemical reformation that terrestrial rocks have.
We now understand that the planets were built out of the collisions of asteroids like these billions of years ago, and the remaining asteroids are mostly objects that failed to coalesce into the planets, locked in reservoirs around the Solar System that are protected from collision with the planets.
Populations like the Main Asteroid Belt, Jupiter’s Trojan asteroid fields, and the Plutinos beyond Neptune all represent locations in the Solar System where a balance exists between the gravity of the Sun and planets, preserving large volumes of asteroids in orbits that delicately dodge each other, preserving these relics. Realtime simulation software now allows us to visualize the motions of tens or hundreds of thousands of asteroids simultaneously, allowing us to see the complex motions that keep these objects (mostly) safe from collision with the planets.
We can partly study asteroids’ geochemistry from afar by looking at the shape of their spectrum in infrared light. This allows us to divide up the asteroids into populations based on their composition. At the most basic level we are familiar with those made mostly of rock and those made mostly of metals, but more detail reveals other differences and relationships among these bodies.
One population of particular interest are the D-type asteroids. These asteroids are often described as having a more “reddish” spectrum. Scattered around the inner Solar System, their spectrum is similar to that of the dwarf planet Pluto and other objects beyond Neptune.
D-types appear to have high concentrations of organic molecules and volatile ices. The migration of the outer planets early in the Solar System’s history may have served an important role in disrupting the outer asteroid reservoir of the Kuiper Belt, now beyond the orbit of Neptune, and sending D-types into the inner Solar System billions of years ago.
The possible role of these asteroids in our cosmic origins are exactly why the Lucy mission took its name after the famous Lucy “missing link” fossil of our pre-human ancestor.
