ASME – Rock Abrasion Tool for Mars Exploration

Introduction

Built on Earth, Proven on Mars

Before its journey to Mars, the RAT endured hundreds of rigorous tests in Honeybee’s laboratories. Engineers utilized basalt from California’s Mojave Desert to replicate the conditions the rovers would encounter millions of miles away.

“We conducted a full test series of over 300 trials using different Earth environments and Mars ambient conditions, employing a vacuum chamber and varying thermal states,” Indyk recalled.

The core of the tool was a small, powerful cutting bit made with diamond and resin. It spun on its own axis while simultaneously orbiting a larger one, carving out perfectly circular, 45-millimeter openings on rock surfaces. The RAT’s integrated brushes swept away debris during operation, leaving behind what Indyk calls “the highest accuracy polish ever achieved off the planet Earth.”

The instrument’s precision stemmed from a blend of mechanics and control. The RAT was stabilized on the Martian surface by two arms nicknamed “butterflies,” which pressed against the rock to guarantee a steady, controlled abrasion.

“The robotic arm would position the RAT on the rock and apply a specific force,” Indyk said. “This method allowed us to know our position with great accuracy and avoid slipping off the surface.”

Designed to strip away only the outer layer, the RAT could grind to a depth of 12 millimeters when necessary. Each meticulously ground circle provided scientists with an unobstructed view of Mars’ genuine geology.

When Spirit and Opportunity landed in 2004, each carrying a RAT, the mission was planned for 90 days. The rovers, however, continued functioning for years—far surpassing all predictions.

“This year marks the 20th anniversary of a highly successful mission originally intended to last just 90 days,” Indyk noted.

Commanding from 140 Million Miles Away

Operating a robotic tool on Mars demanded a complex communication network and meticulous preparation. Teams at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena wrote daily command sequences that were sent via NASA’s Deep Space Network, a system of large antenna arrays in the U.S., Spain, and Australia. These signals were then relayed to orbiters around Mars before finally reaching the surface.

“A common misunderstanding is that operating a rover on another planet is like using a joystick,” Indyk said. “In reality, it requires days of planning, and everything is executed autonomously.”

Because of the approximately half-hour communication delay between Earth and Mars, the RAT could not be controlled in real time. Instead, Honeybee and JPL teams scripted multi-day sequences in advance.

“Tele-operating something on the Martian surface is nearly impossible,” Indyk explained. “But we have a very reliable team and system that has been tested for many years.”

As the Payload Uplink and Downlink Lead (PUL and PDL) for the RAT, Indyk managed both the transmission of commands to the rover and the analysis of the data it sent back.

“It was my job to send all the commands for the RAT’s operations,” he said.

Once data reached Earth, his team confirmed the success of the operations and made adjustments for the next cycle if required.

The Science That Stayed on Mars

The RAT did not collect or store material. Rather, it ground off the weathered outer layers so other instruments could study the newly exposed surfaces in their original location.

“The RAT abrades material, removing the rock’s outer shell,” Indyk said. “Then the other science instruments would examine the interior surface of that RAT hole.”

All of this scientific analysis remained on Mars, as none of the samples were brought back to Earth.
“That would be a different mission,” Indyk noted, referring to the long-awaited Mars Sample Return project.

Even without returning physical samples, the RAT’s influence was deep. The tool’s performance confirmed Honeybee Robotics’ methods for planetary surface engineering and helped establish how future missions would investigate extraterrestrial geology.

“The Spirit and Opportunity Mars Rover Mission was tremendously successful,” Indyk said. “It truly set the standard and raised expectations for all subsequent Mars exploration missions.”

Twenty years later, the circular marks left by the RAT are still visible on the Martian surface—each one a testament to human ingenuity and mechanical accuracy.

“Simply put, the RAT was the geologist’s hammer on Mars,” he said. “It uncovered the planet’s true secrets, one grind at a time.”