How a Solo Cup and an Air Filter Became an Asteroid Collection Tool

Get hype, space nerds. We are just days away from what could be the most exciting launch this year. On September 8, the OSIRIS-REx spacecraft will embark on a seven year mission to do what no other NASA spacecraft has done before: return a substantial amount of asteroid to Earth.

This may sound simple enough, but collecting bits of an asteroid is no easy feat. The target asteroid, a carbon-rich space rock dubbed Bennu, spans 500 meters in diameter and is essentially a big, rotating pile of rubble covered in a layer of dusty surface material called regolith. How do you land on that? The short answer is, you don't.

Physics is the glue that keeps this floating cosmic rubble pile together and understanding the inner workings of these small bodies is crucial to unlocking the secrets of planet formation and evolution.

OSIRIS-REx, which is short for Origins Spectral Interpretation Resource Identification Security and Regolith Explorer, is designed to answer a number of science questions including "Where did we come from?"

NASA's deputy scientist, Christina Richey explained that asteroids, like Bennu, are remnants of the original building blocks of our solar system, and can tell us a lot about the formation that occurred over 4.5 billion years ago.

Asteroids rich in carbon are also teeming with other organic compounds, including the building blocks of life—amino acids—so, scientists believe these small, rocky bodies hold the secrets of how life began.

"We think that these asteroids are a source of water and organic material that eventually made its way to Earth and other planetary bodies early in their history," Richey said.

In order to answer these fundamental science questions, engineers first had to figure out the best way to collect a sample from the asteroid. But how exactly do you do that in microgravity?

Cue Lockheed Martin's own engineering MacGyver: Jim Harris.

Lockheed Martin knows how to build spacecrafts, it's been doing it for decades, so to help solve this engineering quandary, the company held an internal contest among their engineers to generate ideas on how best to scoop up some Bennu.

Regolith is like the dirt we see here on Earth, so naturally when you think of how best to collect dirt, things like scoopers and drills come to mind. All of these devices work great here on Earth; however, in Bennu's microgravity, Harris knew that the traditional methods of collection, like a scooper, would be risky. "The problem is that you have loose material covering a surface with very low gravity," he said. "As soon as you touch it, the material could scatter."

Designs like drills, even a clam-shell scoop proved to be no match for the asteroid's reduced gravity. The team couldn't collect the sample they needed.

Rather than attempting the difficult feat of landing on the surface of Bennu, the team decided on a touch and go approach—basically the spacecraft would give Bennu a smooth, gentle high-five while taking a piece of it home.

Lockheed Martin's chief scientist at the time, Dr. Ben Clark, suggested that Harris take a look at a paper he wrote several years earlier, detailing sample collection on comets. Harris now had a plan. Using a solo cup and an air compressor in his driveway, he came up with the idea to blast dirt particles with air and then collect the ejected particles.

Picture this: a solo cup with holes poked in it. Now picture air being puffed into the cup, with an air filter on the outside. "We used a compressor to blow air against the ground," Harris said. "As the air went out the holes and through the filter, we collected the particles."

To test this theory, Harris and his son went out to their dirt-covered driveway. Armed with his holy solo cup, he set out to prove that blasting compressed air into the dirt would result in dirt being kicked up into the cup. He was right.

Originally dubbed Muucav (vacuum spelled backwards), Jim's design is now officially called the Touch And Go Sample Acquisition Mechanism, aka TAGSAM. Starting as nothing more than a solo cup and an air compressor in one engineer's driveway, ten years and a few iterations later, that bit of crafty engineering has turned into the instrument we see today.

The TAGSAM is attached to the end of an 11-foot-long robotic arm, complete with elbow and wrist joints to help it maneuver into place. What was once a solo cup now resembles the carburetor on a '57 Chevy.

Once the spacecraft has maneuvered itself into prime sample collecting position, the TAGSAM will blast Bennu's surface with nitrogen gas and then hoover up the displaced particles—a process that takes no more than five seconds to complete. TAGSAM is packing three containers of gas, so they will have three chances to collect a minimum of 60 grams (2 oz of asteroid).

It took a bit of work to go from driveway to launch pad, including extensive testing on NASA's vomit comet. However, engineers are pleased with the outcome and testing has shown that the device can collect up to 4.5 pounds (2 kilograms) of material, making it the largest sample returned since the Apollo Moon missions.

We can expect to see the sample back on Earth in 2023 when the spacecraft's asteroid-toting capsule will touch down under parachute in Utah, carrying with it the secrets of the solar system.