NASA's race against time to rescue a falling satellite

NASA's race against time to rescue a falling satellite

A valuable NASA satellite observatory is falling to Earth faster than scientists expected. It's called the Neil Gehrels Swift Observatory, or "Swift" for short, and it can respond to celestial events much faster than its sky-gazing counterparts. To save Swift and test out a first-of-its-kind technology, NASA partnered with an Arizona-based startup to launch a refrigerator-sized robot, aptly named Link, into lower Earth orbit. That's on its way right now to meet up with Swift to give it a boost.

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This episode was produced by Berly McCoy. It was edited by Rebecca Ramirez. Tyler Jones checked the facts. The audio engineer was Jimmy Keeley.

Audio transcript

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EMILY KWONG: You're listening to Short Wave from NPR.

NATHAN ROTT: Hey, Short Wavers, Nate Rott here with updates on a daring rescue mission currently underway, one that-- rest assured, if you haven't heard-- has got all the workings of a good sci-fi movie-- rockets, space robots, and a very valuable telescope.

BRAD CENKO: Swift was designed to study the short-lived flashes of high-energy radiation we call gamma ray bursts.

ROTT: Brad Cenko is a research astrophysicist at NASA's Goddard Space Flight Center. And he's the principal investigator in the Neil Gehrels Swift Observatory, or Swift for short.

CENKO: Swift is a NASA astrophysics mission. It was launched in 2004. It has been doing fantastic science for over two decades now, but unfortunately, it's come into a spot of trouble recently.

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ROTT: Swift operates in low Earth orbit, meaning there's still a little bit of atmosphere for it to contend with, atmosphere that causes it and all satellites at that altitude to lose speed, heat up, and slowly fall back to Earth.

CENKO: But what's surprised us in the last few years is that the rate at which it has fallen has accelerated significantly.

ROTT: Thanks to the sun.

CENKO: You may have noticed that the sun has been much more active in the last year or two.

ROTT: Causing colorful auroras that have been seen as far south as Florida.

CENKO: Those are beautiful. I've seen wonderful pictures, but every time I see one of those, I cringe, because every time the sun does that, it causes the Earth's atmosphere to puff up, and that leads Swift to fall at a faster rate.

ROTT: Brad and other scientists used to think that Swift could keep photographing the sky, expanding our understanding of the universe, until the 2030s. Their latest calculations paint a much less colorful picture.

CENKO: If we do nothing now, it will re-enter the atmosphere probably by the end of this year.

ROTT: Which is why NASA has partnered with an Arizona-based startup to launch a refrigerator-sized robot, aptly named LINK, that's on its way right now to meet up with Swift to give it a boost. Today on the show, the first of its kind effort to save a telescope falling from the sky and how it might shape the future of space exploration. You're listening to Short Wave, the science podcast from NPR.

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ROTT: The Swift satellite is descending faster than you guys anticipated because of the sun's proclivities, right? So what's the plan to try to get it back up there and keep doing its thing?

CENKO: So on Friday, a rocket was launched from the belly of an airplane that took off from the Marshall Islands. That rocket was carrying the LINK spacecraft in its nose. Went up into orbit close to Swift, and everything is working well, all the systems on board. That will continue for another week or so. At that point, LINK will then begin its slow approach towards Swift. Over the period of a couple of weeks, it will attempt to sync up its orbit with Swift, get closer and closer, push Swift into a higher orbit, where it can continue to conduct its science observations. And then ultimately, LINK will let go, drop down to a lower altitude, and burn up in the atmosphere.

ROTT: OK, so you're launching a spacecraft that is going to grab on to this observatory and literally boost it further out of the atmosphere.

CENKO: That's exactly right. It has these three robotic arms that come off of the end. I think of them almost like lobster claws. They just, you know, are designed to pinch and grab hold at three stable points on the bottom of Swift. Once they have established a firm grip and the ability to control Swift, they have an electric propulsion system that will allow it to, over the course of several months, gently push Swift up to a higher orbit so that it can then continue its science observations.

ROTT: A Swift lift, if you will.

CENKO: Absolutely. We-- we've definitely been playing on the Swift themes for some time. It's called that because it can slew very rapidly to repoint its sensitive X-ray and UV telescopes anywhere on the sky within a few minutes, which is a very unique capability in the NASA astrophysics portfolio.

ROTT: It's like the rapid response observatory, essentially.

CENKO: Exactly.

ROTT: Swift. It's swift.

CENKO: That's exactly right, yep.

ROTT: [LAUGHS] I mean, I guess that explains why you guys are trying to save this satellite. It's extremely valuable.

CENKO: That's right. And the only other thing I-- I mean, we talk about this a little bit, but just, you know, honestly, we think this is going to work, but we don't know for sure. It's just a very different kind of mission than we're used to doing at NASA. Ultimately, Swift is going to reenter if it's unsuccessful. You know, Swift was going to reenter anyway, and we've learned a lot through this process. You know, we did this because of the scientific opportunity to demonstrate this exciting new technology.

ROTT: OK, so correct me if I'm wrong, but this is, like, the first time that anything like this has ever been attempted, right?

CENKO: Yes, so this is the first ever attempt to do a capture for a satellite that was not intended to do it. You know, Hubble, for example, has been serviced a number of times by astronauts flying on the space shuttle. But Hubble was designed for that, and it was done by astronauts. It's done by people. This is fully robotic, fully autonomous. And Swift was never designed for this. So it really is a technological first of its kind.

ROTT: And it seems like the timeline that you've all been operating under has been really, really short, too.

CENKO: So not only is this a technical, "first of its kind" mission, but the schedule is also very unique. So we identified this problem a little more than a year ago. We brought on Katalyst in September, and they have been responsible for designing, building, testing, and launching Link in nine months. That is really remarkable. It's just not the timescale we're used to working with when we're doing space missions. You want to test them out. We didn't have the luxury of time in that. We had to come up with new ways to do things. And hopefully that will teach us, NASA, how to work with commercial partners, how to, you know, work faster when it's really necessary to do that.

ROTT: And so far, it's seeming like, yeah? I mean, this mission has launched.

CENKO: Yes.

ROTT: OK.

CENKO: The same day, apparently, that another Swift was in the news.

ROTT: [LAUGHS] She's always upstaging people. I was going to ask you at some point if all this work about Swift officially makes you a Swiftie.

CENKO: 100%. I think it comes with the territory, for sure. We would love-- if she's listening, we would love to partner with her.

ROTT: OK. When that partnership happens, I want to be there on the red carpet watching it.

CENKO: You'll be the first invite. Don't worry.

ROTT: Taylor Swift partnership aside, you're talking about how this is a "first of its kind" mission, "first of its kind" attempt. Do you see this technology being used going forward?

CENKO: I think this could significantly change how low Earth orbit environment works. Right now, every satellite, ultimately, it re-enters, burns up in the Earth's atmosphere. But you could easily imagine a world where you replenish them, change the batteries, put new instruments on board. This could potentially lead to a much more sustainable low Earth environment. There are also, obviously, defense applications for this. You can imagine the ability to change the trajectory of a satellite would be of great interest to folks on the, you know, defense world. And NASA, you know, I would say, very wisely saw Swift as an opportunity, not only to save a scientific mission, but also to develop this capability with its broad applications.

ROTT: It's saving a scientific mission, and it's a scientific mission in and of itself.

CENKO: Yeah, absolutely, 100%.

ROTT: Cool. And so in a month, roughly, it's going to make contact, and it's going to start its Swift lift.

CENKO: That's the idea. When it gets a little bit closer, it'll take a bunch of pictures. And this is for two reasons. One is because we actually don't know what state Swift is in. We haven't seen it in 22 years. And we want to verify that the observatory, all is behaving like we think it should and make sure that the points where the robot is going to grab on to Swift are the right ones. And the second reason is because the actual capture itself is all done autonomously. And so the Link spacecraft has a bunch of cameras on board. It needs to train those cameras in the same way that, like, a self-driving car is trained, so that it knows, OK, I'm this far away. I need to fire these thrusters, get a little bit closer. My robotic arms are here. I need to maneuver them in this direction. All that is happening using computer vision software that's on board. And we need--

ROTT: Wow.

CENKO: --actual images of Swift in different orientations and different lighting conditions to train that capability.

ROTT: Would you say you're cautiously optimistic about Swift's chances?

CENKO: Absolutely, 100%. The fact that we have gotten this far, I think, is remarkable. You know, there is something on orbit that is, you know, working thus far pretty well. That leads me to think that, you know, we're going to continue to do well. But still, we have a lot of challenging things ahead of us. And so it's going to be an exciting ride for the next couple of months.

ROTT: All right, Brad. Well, let me know when Taylor Swift gets in touch with you, and you create that partnership. And otherwise, I will keep a close eye on the progress of this mission, and excited to hear how it goes.

CENKO: I appreciate it. Thank you so much.

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ROTT: Short Wavers, do us a favor, and follow us on the NPR app or wherever you listen to podcasts. We're here every Monday through Wednesday, plus Friday for funsies. This episode was produced by Berly McCoy, edited by our showrunner, Rebecca Ramirez, and fact-checked by Tyler Jones. The audio engineer was Jimmy Keeley. I'm Nate Rott. Thanks for listening to Short Wave from NPR.

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