Shrinking surgical robots for space

Virtual Incision relied on fast prototyping to create spaceMIRA, an FDA-approved robot that could herald a new era in surgery on Earth and beyond.

Adding “must be able to fly to space” as a design constraint adds a whole new level of engineering challenge. There’s new weight and vibration requirements, size limitations, and a whole lot more that can require significant design changes to a perfectly laid out plan.

For MIRA, more formally known as a Miniaturized In Vivo Robotic Assistant, space was just another useful step in a carefully planned out development cycle. Created by company Virtual Incision, this small robotic surgeon recently made headlines by successfully completing a robotic surgery tech demo aboard the International Space Station (ISS). Getting there took more than a decade of engineering, CAD design, motor development, and testing to make those space headlines a reality, but it could have a bigger impact in hospitals here on Earth.

NASA astronaut Loral O’Hara shows off the miniaturized in vivo robotic assistant (MIRA) aboard the International Space Station. (Image: NASA.)

Developing a space robot

Surgical robots on Earth have very large footprints, so until recently sending one to space wasn’t even an option. covered Virtual Incision for the first time in 2014, and they already had their eyes on space. At that point the company’s robot wasn’t yet called MIRA, but it had been in the works for many years.

“The early robots we made were actually like rovers. They would drive around inside the body and do roving type tasks,” Virtual Incision chief technical officer Shane Farritor told “But as we did more and more, we wanted to get more active in what we were trying to do, and we added arms to our device. Now we make a two arm manipulator with an integrated camera.”

There have been more than 100 iterations to get to what is today known as MIRA. That meant there’s been ample time in CAD software and the machine shop. Virtual Incision uses a number of CAD programs for their design, but Solidworks is their primary tool. They use a laser welder, laser cutters, simple CNC equipment, mills and injection molding equipment to develop their prototypes.

“We really build robots quickly and try them quickly. I think that’s been really important in our development cycle,” Farritor said.

Making these robots smaller isn’t just to make them available for niche astronaut emergencies. It’s also about making them deployable in rural areas on Earth, military front lines, and even in your neighborhood hospital where large robots struggle to fit.

“Simplicity is really the key. Size is one aspect of simplicity, but there’s a lot more to it than that. We really work to simplify the cabling, which doesn’t seem like such a big deal, but cabling can get out of control in an operating room,” Farritor said.

MIRA, Virtual Incision’s miniaturized robotic assisted surgery system, is pictured in position to reach simulated surgical tissue. (Image: NASA.)

Measuring under two feet in length and around two pounds, MIRA’s size is driven by a lot of factors which can often be at odds with each other. The robotic arm needs enough range and force to perform surgeries in humans of all sizes at reasonable speeds. It also needs to be as small as possible while accommodating the requirements of the electrical and mechanical elements needed to make that happen.

Farritor credits Virtual Incision’s ability to shrink the size of their device largely to the motors and drive trains they have developed with their partner manufacturer. Rather than using direct drive motors placed on the outside of the robot, they chose to place the motors in the device itself. This eliminated the need for large transmission cables.

“The fact that our motors are co-located with joints makes our device incredibly strong, and in some ways very simple,” Farritor said. “There’s a lot of energy density in our devices.”

ISS as a testbed

Going to space alone is a challenge. Getting FDA approval at the same time is another level of difficulty. Virtual Incision submitted around 40,000 pages of documents and performed a clinical trial to receive Food and Drug Administration (FDA) marketing approval, while also figuring out vibration testing for a space payload.

“Surgery on people is a very serious matter, so we want to make sure we’re doing the best we can,” Farritor said. “Honestly, the space flight was a subset of all that. There were some additional extra things we had to do, but it was pretty manageable because of the rigors we’d already gone through to make sure our device worked.”

spaceMIRA in front of the EXPRESS rack box it was loaded into for launch. (Image: NASA.)

That doesn’t mean changes weren’t required for a trip to the ISS. The custom version of MIRA that went to the ISS, spaceMIRA, is not an exact twin to its Earth counterpart. The arm and its cables are shorter by about three inches. The design change was needed so that it would fit diagonally in one of the ISS’s standard sized experiment boxes.

On January 30, 2024 spaceMIRA lifted off onboard a SpaceX Falcon 9 Rocket in Northrop Grumman’s Cygnus spacecraft. Just to add to that hectic time, in February 2024 Virtual Incision received market authorization from the FDA.

Back on Earth, six surgeons had the chance to try their hand at controlling spaceMIRA while it orbited 250 miles above Earth. Together the team was able to overcome an about 800 millisecond signal lag to remotely cut a set of rubber bands that had been set up alongside the robotic arm in the box launched to the ISS.

One of those surgeons was Dr. Theodoros Voloyiannis, who has performed more than 1,000 robotic-assisted surgeries on Earth.

“It makes you feel like your first years, where you’re very cautious of what you do. And once you get acquainted with it, it becomes a little bit more of a normal task,” Voloyiannis said in a podcast interview with NASA.

Shane Farritor (left) watches as Dr. Michael Jobst remotely operates a surgical robot aboard the International Space Station using controls at the Virtual Incision offices in Lincoln, Nebraska. (Image: University of Nebraska-Lincoln.)

The ISS is just the first space flight step for MIRA. Just as you might test a tractor in a small outdoor space next to a factory, engineers need to perform smaller tests of their devices in Earth’s backyard before sending them on long duration missions or to other planets. The International Space Station has served as that microgravity test bed for about 24 years now. Whether you need to expose a material to the harsh environment of space for a long duration, or you want to quickly test out your space robot, the ISS works for both.

“We hope the NASA mission leads to other NASA missions, but we also hope it really has a big impact on surgery here on Earth,” Farritor said.

A new era in surgery

When we spoke to Farritor, spaceMIRA was sitting in a still-sealed in a box directly behind him. Awaiting him in that box was the arm itself, kinematic and motor current data, an SD card containing tons of unseen video, and information that will allow the engineering team to compare how the robotic arm operated in space with how it operates on Earth. Although the team was able to determine certain levels of success from a distance, now they will get more specifics and see how the robot fared on the ride home aboard a SpaceX Dragon capsule.

Virtual Incision’s next steps are to take this data and continue what the company has been doing all along: making the next version of MIRA.

“I suspect we’re going to have follow-on devices that will continue to improve and continue to reduce in size,” Farritor said.

After getting his hands on the robot controls while it was in space, Voloyiannis is confident MIRA is going to make a big medical impact: “I think it’s the beginning of a new era in surgery.”