NASA's Robonaut to Return to Space Station With Legs Attached

NASA has fixed Robonaut and is nearly ready to send it back to the International Space Station

7 min read

NASA's Robonaut
NASA wants to use Robonaut as a test-bed to develop future robotics technology for space outposts on the moon and Mars.
Photo: Evan Ackerman/IEEE Spectrum

A little over a year ago, we reported on the status of the Robonaut 2 on the International Space Station. Things had not gone all that well for R2 ever since an attempt had been made to install a pair of legs back in 2014, leading to an intermittent power problem that was very hard to diagnose. NASA brought Robonaut back to Earth last year for repairs, and a few weeks ago, we stopped by NASA’s Johnson Space Center (JSC) in Houston, Texas, to visit the Robonaut lab and get an update on what’s been happening with R2.

NASA's RobonautThe Robonaut team plans to perform a variety of mobility and motion-planning experiments using the robot’s legs, which can grab handrails on the ISS.Photo: Evan Ackerman/IEEE Spectrum

The Robonaut lab is in Building 9 at JSC, attached to the space vehicle mockup facility. JSC’s Valkyrie lives in this massive high bay, and was busy practicing a bomb disposal task (!) when we peeked in. NASA also keeps a bunch of other robots in here that have been gently retired, including Centaur, which is kind of like a Robonaut torso stapled to a wheeled rover. In the Robonaut lab next door, three different Robonaut 2s (one with legs) were busy doing Robonaut things, and we sat down with Julia Badger, Robonaut Project Manager, for an update.

IEEE Spectrum: Can you get us caught up with what’s been going on with Robonaut since our last article a year ago? Did it make it back to Earth from the ISS?

Julia Badger: Robonaut came back last May, and we got it back a few weeks later. Within the first few days, we found that what we’d thought was wrong with it on-orbit was indeed what was wrong with it: We were missing a ground path, so the computer chassis [in its stomach area] essentially didn’t have the correct path to return its current, and it was finding sneak paths. The sneak path it went through ended up causing more damage than we would have expected, so we’ve been spending these past eight months fixing it.

We also spent a decent amount of time figuring out what else about Robonaut we didn’t have up-to-date documentation for. The first time around, the certification unit (R2-C) was built after we’d actually flown the flight unit. So one of our major objectives has been to make our certification unit identical to our flight unit. As we did that, we decided to go through and assess and mitigate some other problem areas. It’s not a complete redesign or anything, but there was a decent amount of electrical reworking. The same boards are in place, and they’re doing the same functions; we’ve just moved around some power components. 

That all finished up at the end of last year, and we’ve been taking the flight unit through panels and certification tests since then. We’ve done EMI [electromagnetic interference], and we’re almost all the way done with the computer network tests. We’re going to be doing vibration testing in a couple weeks. We’re actually on the integrated payload list now to return R2-B (our flight unit) back to station. We’re not on a flight yet—we have to get through all of our safety certifications and everything signed off before we can be assigned to a flight, but we’re not far off. So we’re working pretty hard to get to the end line. Our aim is that we have a bow on it by May, which would be one year to turn it all around, which isn’t so bad. 

Why send up the same R2-B unit when you could send up a newer C-series R2 instead?

We thought about that. There are a number of things that we had to do to R2-B to make sure it could go up, like conformal coating all of the electrical boards, which takes a lot of time and costs a lot. Those are not done on R2-C1. So it’s essentially all the same except for a few things, but those things were actually fairly costly and time consuming.

And R2-B is no longer really a true B, it’s now a C. We brought the B up to where the C is. We’ve been using C1 [the certification unit] on the ground, and it’s been working just fine. Our workhorse is C6; that one will do 8 hours a day no problem; we’ve put thousands of hours on it. So really, when we did our documentation, we went from C6, to C1, to B.

What’s the plan with Robonaut’s legs? Will you be able to send them back up already installed?

The legs and the upper body will be connected, hopefully—I think the only thing we’re going to have to take off is the backpack [used for power processing] when we fly it again. We’re working with the people who do the [packing] foam to make sure that’s the case. [The backpack] is just four screws, it’s not terrible.

The legs are key to all of our research objectives when we get back up on ISS. Since we last talked, Gateway became a program, so we’re going to have a space station in orbit around the moon. One of the systems on board Gateway is going to be intravehicular robots. They’re not going to necessarily look like Robonaut, but they’ll have some of the same functionality as Robonaut—being mobile, being able to carry payloads from one part of the module to another, doing some dexterous manipulation tasks, inspecting behind panels, those sorts of things. And so the legs are really key to being able to push the readiness level of some of the pieces of technology we’ve been demonstrating on the ground for the past three to five years. 

“We really want Robonaut to be a test-bed to advance the technology so that the next generation that will be on the Gateway lunar outpost is the workhorse that goes and does all the things that will need to be done.”

Will Robonaut be using its legs to move away from the position that it’s been stuck in until now?

Yes. There are these blue handrails that the crew uses to either stick their feet under to stay stationary, or to move through the labs. Robonaut’s feet grip  those, and we’ve been working to string together multiple steps. It should, theoretically, be able to do what we can do on the ground, which is, take two or three steps completely unassisted. It’s only going to be in one lab, because it’ll have a [power and communications] tether, but I think we’re going to be able to show quite a bit even with that.

How much autonomy will Robonaut have?

We’re trying to be really specific about the types of tasks that we want the robot to be doing so that the robot can do those tasks without human intervention as much as possible. Otherwise, if you have to have a ground controller doing it for the robot, it’s not worth it. So the robot doing tasks where it needs to be “flown” by a ground controller is going to be outside the realm of the usual. Not that we’re not ever going to do it, but it’s going to be because something unexpected happened and we need to step in. What we’ve found is that the teleoperation, telling it exactly what to do, isn’t really conducive to the low bandwidth that you get from here to station, and Gateway is supposed to be lunar and Mars forward, and then you get even farther out of that range.

We’ve been working with Lydia Kavraki’s group at Rice University to get the motion planning and path planning such that it can handle all of our 58 degrees of freedom, and it does a really good job on its own. 

How dependent will Robonaut be on crew time?

We’ll need crew time to get set up, but we don’t need crew time for most of our work. We can do 8 hours of experiments [including moving around] while the crew does other things. We’re probably going to be stowed in a bag, so we’ll need to be unstowed and attached to structure. We’ll need a couple cords for power and for Ethernet, and then they’ll need to flip the switches. Unless something goes wrong, we won’t need to see them again until they pack us away.

Would this generation of Robonaut be able to help out the astronauts with any practical tasks?

That’s not really what we’re going for—what we’re going for is the technology development to be able to get to there. We’re hoping that Robonaut will be a test-bed for other NASA research, and even university research. ISS isn’t really meant for a robot to service it, and there’s always people, and people are going to be faster. So could it go and clean off handrails and stuff? Yes. But are we going to push for that? No. We really want it to be a test-bed to advance the technology so that the next generation that will be on Gateway is the workhorse that goes and does all the things that will need to be done when there’s no humans on board.

Does that mean that Gateway will be designed more with robots in mind rather than being just an environment for humans?

Yeah, absolutely. We think that the systems approach is the right approach to the designing of Gateway. If want a system that can be serviced by robots and humans, it should have a design that both humans and robots can use.

NASA's RobonautWhile Robonaut can be teleoperated, NASA wants the robot to be able to perform tasks without human intervention as much as possible.Photo: Evan Ackerman/IEEE Spectrum

Gateway is still a few years out, even under the best of circumstances, but it’s clear that robotics will be an integral part of NASA’s plans to expand beyond low Earth orbit. Robots like Robonaut and Astrobee are part of a larger push toward automated systems in space, and frankly, it’s about time—we humans are fragile, needy little things, not at all designed for space, and robots can do many of the things that we can do in a safer and more affordable way. Or at least, they have the potential to be that useful, if we can program them to be, and we’re looking forward to Robonaut proving its usefulness over the next few years on-station.

We don’t yet know exactly when Robonaut will be launched back to the ISS, but we hope that it’ll be as soon as possible. Astrobee is already up there, and it could (literally) use a hand. And with the power problems fixed and new legs already installed, Robonaut is more capable than ever. Let’s see what it can do.

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