A mothership that emits power with a laser beam to manipulate a probe craft in deep space. A robot that extends its arms to climb in Martian caverns and grasp objects.
These are innovations you might expect to see in a science fiction movie – one where the hero embarks on interplanetary travel across the solar system. But they are also are visionary ideas from the minds of Stanford University researchers that have already received funding from the NASA Innovative Advanced Concepts (NIAC) Program.
Illustration of ReachBot traversing a Martian cavern using microspine grippers across different types of treacherous terrain: (left) a vertically winding tunnel with a rocky and uneven floor, (center) an overhanging wall or ceiling and (right) a sheer vertical wall. Image credit: Marco Pavone
As 2021 NIAC fellows, Sigrid Close and Marco Pavone – both associate professors of aeronautics and astronautics – are being given the chance to prove the feasibility of their inventive concepts, known as SCATTER and ReachBot. Close and Pavone are among 14 other NIAC Phase I recipients who are receiving $125,000 to fund nine-month studies on their research ideas. Though their ideas might seem out of this world, should they succeed, they’d drastically impact space exploration.
Over the course of her funding, Close is working on proving her concept SCATTER, which stands for Sustained CubeSat/CHIPSat Activity Through Transmitted Electromagnetic Radiation. The idea is that a spaceship on a mission to deep space will be able to power and control a probe with a transmitter.
SCATTER focuses on a mission to Uranus, but according to Close’s collaborator Nicolas Lee, a research engineer in the Department of Aeronautics and Astronautics, it can be applied to other deep space missions as well.
Illustration of the mothership and probe subsystems in the SCATTER concept. Image credit: Sigrid Close
“In general, small spacecraft have been powered by either solar or batteries,” said Lee. But on a mission to a planet far out in the solar system, like Uranus, using the Sun’s rays isn’t feasible. “In terms of the other options with batteries, you have limited life so you can use that for very short-term missions.”
By beaming a laser from the mothercraft onto a probe, which can then convert the energy from the laser into electrical energy, the team believes they can sustain long-term missions, especially with small, low mass probes.
“A few years ago, we started thinking, ‘Well, we’re always talking about protecting satellites from the space environment,’ ” said Close. Then, they wondered, What if we can harness some of that energy?
“Even though it’s different from how it started, we started looking at different ways to power spacecraft using the space environment and then just kind of extended it from there,” she explained.
In the coming months, Close and Lee will be working on figuring out how small and simple they can make the deployable spacecraft so that they can use the laser to not only power the spacecraft but communicate and control pointing with it.
According to Lee, the funding they receive will really allow the researchers to explore the mission concept side of SCATTER.
“It’s an honor,” said Close. “I’m really grateful to NASA and the NIAC committee for giving us this opportunity.”
When asked about the inspiration behind ReachBot, Andrew Bylard, a graduate student in aeronautics and astronautics who works in Pavone’s lab, is quick to cite an unlikely couple: Spider-Man villain Doctor Octopus and lovable Star Wars sidekick BB-8.
“The idea of ReachBot was born from this kind of technological gap that exists in robotics today,” said Stephanie Schneider, who is also pursuing her PhD in aeronautics and astronautics while a member of Pavone’s lab.
In microgravity environments like the International Space Station or when climbing under gravity on Mars or the moon, crawling robots have to grab anchor points to move and manipulate objects without floating away or falling. If anchor points are few and far between, the robots are limited by how far they can reach.
ReachBot increases its reach using “extendable booms,” which extend out from its sides, like measuring tape. The booms can be rolled up compactly and, when unrolled, they are sturdy cylinders with lightweight grippers on the ends – which can grab objects, be used to anchor the bot to a certain point or push off of surfaces like a leg to move ReachBot around.
One compelling use for a bot like this is the exploration of Mars. While the Mars rovers are great at rolling along the surface, ReachBot would be capable of climbing on cliffs and through caves.
Right now, the team is in the early stages of working on a hardware prototype of the bot. Over the course of their NIAC Phase I funding, they plan to focus on proving the feasibility of ReachBot concept, including working with mechanical engineering professor Mark Cutkosky and geological sciences professor Mathieu Lapôtre to design new lightweight spiny grippers and to refine the science objectives for a climbing mission on Mars.
The biggest challenge to overcome will be working on the motion and maneuvering of ReachBot’s “arms.” But the rewards for a robot that masters mobile manipulation under such challenging gravity restraints are high.
“The ultimate pay-off for space robotics is really to enable your science,” said Pavone.
Not all NIAC fellows make it past Phase I. The projects are often described as “high-risk, high-reward”: ideas that may seem technologically out-there, but should they succeed, they’d have a huge impact on space exploration.
“I think it’s really important that, as a community, we fund these kinds of cutting-edge ideas and take those risks,” said Close, whose concept for a small satellite to characterize asteroid surfaces received NIAC Phase I funding in 2018.
Pavone, who was previously awarded a NIAC Phase I fellowship in 2011 for his concept of a hopping robot for navigating on asteroids and comets, thinks it’s important to have a different outlook on what “failure” means.
“Even if we fail – or in general one of these concepts fails – typically what happens is that during the process you discover some other things, or some parts of the concept that you develop could be useful for other purposes,” said Pavone.
“So yeah, many of these concepts fail in the sense that the precise proposed mission is often never flown but if you look at the broader picture, I would actually argue that most of the concepts succeed.”