TERP RAPTOR: A student-built mission to asteroid Apophis

**Sarah Al-Ahmed** (0:03)
A team of university students is building a spacecraft to chase down asteroid Apophis this week on Planetary Radio.
I'm Sarah Al-Ahmed of The Planetary Society, with more of the human adventure across our solar system and beyond.
On Friday, April 13th, 2029, asteroid Apophis will pass closer to Earth than our geostationary satellites. While NASA, ESA, and JAXA are all sending missions to rendezvous with the asteroid, a group of students at the University of Maryland decided to join the fleet. Their mission is called Terp Raptor, a CubeSat-based spacecraft that aims to fly by Apophis and snap images of the surface as it approaches Earth. Four members of the team join us today to talk about how the graduate class project became a space mission, what they hope to learn, and why they're building a spacecraft from scratch before they've even graduated. Then Bruce Betts, our Chief Scientist, joins us for What's Up, where we'll mark the deployment anniversary of the Planetary Society's own CubeSat-based mission, LightSail 2
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When astronomers Roy Tucker, David Tholen, and Fabrizio Bernardi spotted a new asteroid from Kitt Peak National Observatory in June 2004, they had no idea it was about to cause a global scare. The asteroid was named Apophis after the Egyptian serpent god of chaos. Within months, the asteroid was given a 2.7% chance of slamming into Earth in 2029 It was the highest threat rating any asteroid had ever received. For a brief, uncomfortable moment, the world had to reckon with the possibility that a rock roughly 350 meters across, about the height of the Eiffel Tower in France, might be headed straight for us.
The energy of that kind of impact would be the equivalent of more than a thousand of the most powerful nuclear weapons. It wouldn't be enough to end human civilization, but it would be enough to devastate an entire region of our world.
Thankfully, follow-up observations ended up ruling out that impact in 2029, and radar tracking data during its flyby in 2021 confirmed that Apophis poses no threat to Earth, at least not for the next hundred years. But it's still coming really close. On Friday, April 13th, 2029, Apophis will pass just 30,600 kilometers above Earth's surface. Around two billion people across Europe, Africa, and Western Asia are going to be able to see it with the naked eye. This kind of event, a potentially hazardous asteroid that large, passing this close without hitting us? It's estimated to happen only once every 7,500 years. That rare opportunity has drawn a fleet of spacecraft. NASA's OSIRIS-APEX mission, which is a repurposed asteroid sample return spacecraft, is going to rendezvous with Apophis shortly after its flyby. They're going to study how Earth's gravity will reshape its surface and rotation. And then there's the RAMSES mission, which is being built by the European Space Agency and the Japanese Aerospace Exploration Agency. That mission is going to arrive to Apophis several months earlier, so it can observe the asteroid before, during and after the encounter. And then there's the mission that we're about to talk about today. In the fall of 2024, a group of students at the University of Maryland sat down on a graduate aerospace engineering course taught by Brent Barbie, a planetary defense scientist at NASA Goddard. They set out to design a mission to Apophis. But what started as coursework quickly became something much bigger. They named their mission Terp Raptor. It stands for the Terrapin-engineered rideshare probe for rapid response asteroid Apophis profiling, tracking, observing, and reconnaissance. Man, I love space acronyms. Terp Raptor is now an official University of Maryland initiative aiming to build and launch a CubeSat-based spacecraft to image Apophis during its close approach. CubeSats are miniature spacecraft built to a standard size. A single unit is just 10 centimeters on each side. They're designed to make it cheaper and easier for universities and small companies to fly spacecraft. Today, we're joined by four members of the Terp Raptor team. Adrienne Rudolph, who's the student principal investigator, Elena Wu, the lead project manager, Tyler Autrey, the mechanical structure and material lead, and Xander Williams, the propulsion lead. Here's my conversation with the Terp Raptor team.
Hey, everyone. Thanks for joining me.

**Adrienne Rudolph** (5:14)
Thanks for having us.

**Elena Wu** (5:15)
Yeah. Thank you.

**Tyler Autrey** (5:16)
Thank you.

**Alexander Williams** (5:17)
Thank you.

**Sarah Al-Ahmed** (5:18)
Adrienne, I understand that this whole thing started as a graduate course project. At what point did this go from a class assignment to, we're actually going to try to send this to space, you guys.