Double take: Satellites to get an eye on asteroid pairs

In just three years, a new space mission led by CU Boulder could examine some of the solar system’s most dynamic duos: binary asteroids.

NASA announced this week that the Janus: Reconnaissance Missions to Binary Asteroids mission had been selected as a finalist in the space agency’s new small satellite program called SIMPLEx.

The SIMPLEx program seeks to send miniature spacecraft, in many cases weighing less than 100 pounds, into space to explore diverse scientific questions. Each of the three selected finalist missions will have a maximum budget of $55 million, and Janus has a proposed launch date of 2022.

Janus, named for the two-faced Roman god, will employ a pair of these small satellites to collect unprecedented data on systems in which two asteroids revolve around each other a bit like Earth and the moon.

Daniel Scheeres, a professor in the Ann and H.J. Smead Department of Aerospace Engineering Sciences, leads the Janus project. 

He said that while binary asteroids make up at least 15 percent of all asteroids, scientists have never been able to get a close look at one. 

“There are many theories of how binary asteroids form, but we haven't had the proper measurements to sort through them all and see which is correct,” Scheeres said. “The Janus mission will do this and also help us better understand how primitive bodies in the solar system have formed and evolved over time.”

Other CU Boulder team members on the mission include Jay McMahon, an assistant professor in aerospace engineering, and Paul Hayne, an assistant professor in the Department of Astrophysical and Planetary Sciences and the Laboratory for Atmospheric and Space Physics.

Solar system origins

If NASA gives the mission final approval, Lockheed Martin will build the twin spacecraft and manage their operations. Malin Space Science Systems will build the mission’s scientific instruments.

“The Janus mission is a testament to CU Boulder’s legacy of exploring the solar system and our close partnerships with aerospace industry leaders like Lockheed Martin,” said Bobby Braun, dean of the College of Engineering and Applied Science. “The university is a national leader in the development and operation of small spacecraft that generate unprecedented insights on our home planet, our sun, our solar system and exoplanets for a fraction of the cost of traditional space missions.”

McMahon added that the mission could gather important new clues to how the solar system—and the planets that populate it—first came into existence.

Billions of years ago, bodies like Earth formed from smaller rocks that clumped together and grew over time. Binary asteroids, he said, are part of the subsequent evolution of asteroids that were left over from those planet-sculpting days. 

“Every clue we get about how binary asteroids have evolved since that time puts more constraints on how the solar system formed, how Earth formed,” McMahon said.

The team already has its eyes on two sets of these duos—binary asteroids called 1991 VH and 1996 FG3, both of which have orbits that periodically bring them close to Earth.

Once the group’s twin satellites meet up with those asteroids, the spacecraft will image them using visible light and infrared cameras, recording detailed information about how they move and what they’re made of. 

“We can’t wait to get started,” McMahon said. “We’re really excited to be selected, and I’m looking forward to gaining an unprecedented look at these never-before explored solar system bodies.”

The Janus science team also includes CU Boulder alumnus Christine Hartzell at the University of Maryland and researchers from NASA’s Jet Propulsion Laboratory, the Planetary Science Institute, the University of Hawaii and the Czech Academy of Sciences.