Dr. Robert Herrick is probably Alaska’s foremost expert on Venus.
“Venus right now does not have a magnetic field. It also rotates extremely slowly. It also rotates in the opposite direction from the direction it goes around the sun. So it's unusual among the planets that it does that,” Herrick said.
There are three missions to Venus planned in the next decade. Herrick says Venus is now getting attention because it is about the same size as earth. And more and more astronomical discoveries of earth-sized planets revolving around stars brings up the question:
“Does earth size mean earth-like?”
Earth and Venus are sister planets with similar mass, and close enough to their sun. But the surface of Venus is uninhabitable, and Herrick wants to know if it ever had life. He’s hoping this mission will get a good look at the surface of the planet, and what it is made of.
“On earth, the rocks, that make up the continents have more of the mineral silica than the rocks that make up the ocean floor. It's very difficult to make these silica-rich rocks on a large scale without having plate tectonics circulating water into the interior. And so this would be a big indicator that at some point in Venus' past, it had a lot more hospitable climate and it might have been inhabitable for a big portion of its life,” he said.
Herrick is working on a type of synthetic aperture radar that can penetrate Venus’ dense cloud layers and image and map the planet’s surface. It is called VenSAR instrument, and NASA will build it in the next few years in California.
The radar system will launch as part of the European Space Agency’s EnVision mission to Venus.
Herrick was selected for his expertise on Venus, but it didn’t hurt that he’s at the Alaska Satellite Facility, where planetary synthetic aperture radar systems attract researchers and graduate students.
UAF alum Zhong Lu, who obtained his Ph.D. in geophysics at UAF in 1996, is also on the VenSAR science team. Lu is a professor at Southern Methodist University’s Dedman College of Humanities and Sciences.
Herrick is also working on the science team for a U.S. Venus mission: the Venus Emissivity, Radio Science InSAR, Topography and Spectroscopy mission, or VERITAS. And NASA has a second US mission to Venus called Deep Atmosphere Venus Investigation of Noble gasses, Chemistry, and Imaging mission, or DAVINCI. VERITAS and DAVINCI are the first U.S. space flights to Venus since the Magellan program ended in 1994.
“I entered grad school right as, uh, the Magellan mission was launching. And so, um, so yeah, I've been studying Venus since the late 1980s,” he said.
“Because VenSAR operates at a similar wavelength to the NASA Magellan mission from the 1990s, we will be able to identify surface changes over a four-decade time span,” Herrick said.
Right now, the Japanese spacecraft Akatsuki is orbiting Venus, but too high up for surface research.
VERITAS, DAVINCI, and EnVision are scheduled to launch at three time points when earth and Venus are close together, called inferior conjunctions, starting in December 2027.
“I'm old enough that I'll be retired semi-retired by the time particularly the European mission is collecting data,” he said.
He came to UAF to help develop a once-imagined Planetary Space Research project, and stayed to do his own research.
But there is a new generation of space scientists getting ready. Researcher Indujaa Ganesh arrives in Fairbanks this fall, making UAF the only organization with two scientists on the 14-member VenSAR science team.
Robert Herrick says VenSAR’s imagery might confirm some theories about Venus and throw others out. It could show the chemical composition of the crust, and the context between different geologic features that will tell more of the planet’s history.
