Early Wednesday morning, NASA will launch a rocket carrying a spacecraft on a mission that could be drawn straight from science fiction lore.
The target is an asteroid about 525 feet wide that is currently orbiting a much larger asteroid millions of miles from Earth. The mission: hurtle into the chunk of celestial rock at 15,000 miles per hour to knock it off course. Impact is expected in fall 2022.
The launch is a first-of-its-kind take on “planetary defense.” Researchers hope it will be a crucial tool in their armamentarium against potentially devastating near-earth asteroids. One of the effort’s lead investigators is a Massachusetts Institute of Technology graduate whose dabbling with asteroid research at the university in his undergraduate years laid the groundwork for this role.
“I’ve always been interested in stars and space and planets since I was a kid,” said Andy Rivkin, who graduated from MIT in 1991 and returned to the school nine years later as a research scientist. “At MIT, I was in the earth, atmospheric, and planetary sciences department, and that’s when I started looking at asteroids. And then as a graduate student, I studied asteroids. And then I ended up doing my dissertation on them. It sort of all started [at MIT].”
Rivkin, who is 52 now and a researcher at Johns Hopkins University, is one of two investigative leads on NASA’s Double Asteroid Redirection Test, also known as DART. If the redirection is successful, it would be a major breakthrough that offers humanity another option of defense in the improbable, yet entirely possible, scenario in which a mid-sized or large asteroid is on a collision course with Earth.
“You know that saying, ‘If all you have is a hammer, then everything looks like a nail?’” Rivkin said in a telephone interview Tuesday morning. He said the mission could demonstrate that there’s an alternative to blowing up the asteroid with a nuclear bomb.
“Right now, the hammer we have is a nuclear device. We’re really just trying to put some more tools in the toolbox,” he said.
To be clear, the asteroid in question, Dimorphos, is not headed for Earth. Neither is its parent asteroid, Didymos. Wednesday’s launch is a test to see whether NASA’s team can pull off a highly complex effort of this nature.
The spacecraft, which is a bit smaller than a typical compact car, is set to launch Wednesday aboard a SpaceX Falcon 9 rocket at exactly 1:21 a.m. EST from the Vandenberg Space Force Base in California. The rocket will carry the DART spacecraft into an orbit with the sun and onto a direct collision course with Dimorphos, a moonlet around the size of a football field.
The mission will be tricky. Dimorphos and Didymos function as what’s known as a binary system. Dimorphos orbits Didymos as its moon. And Didymos, a much larger asteroid measuring 2,500 feet in diameter, roughly the height of the Burj Khalifa, orbits the sun.
NASA and its team of researchers from Johns Hopkins University’s Applied Physics Laboratory will attempt to line up the spacecraft’s orbit around the sun with those of the tandem asteroids. They’ll aim to have the spacecraft collide head-on with Dimorphos in late September or early October at one of the asteroid’s closest points to Earth — about 6.8 million miles away.
In theory, a collision with Dimorphos at such force will alter the asteroid’s orbit ever so slightly. Researchers estimate the asteroid’s current complete rotation around its parent of just under 12 hours will be shortened by about seven minutes.
As minimal as that difference may sound, in an instance where a celestial rock is hurtling toward Earth, it could be the difference between a devastating impact and a near-miss.
It’s after the crash that Rivkin will come in, studying Dimorphos’s orbit around Didymos through powerful telescopes.
The work, Rivkin explained, is much like the research he has done since the outset of his career.
“The roots of his expertise today go back to the undergraduate days at MIT and he’s since become a leading voice in this field,” said Richard Binzel, Rivkin’s undergraduate adviser at MIT who is now his long-time research partner.
Researchers estimate there are somewhere around 25,000 near-Earth asteroids that measure close to 500 feet, or big enough to cause “regional devastation” should they collide with the planet. Only about 40 percent of them have been located.