Planetary Radio: Space Exploration, Astronomy and Science - Planetary Radio Extra: LightSail Update

Episode Date: February 9, 2016

The Planetary Society's Bruce Betts and Jason Davis join host Mat Kaplan for a status report on LightSail 2, the Society's next solar sail, now being prepared for launch as soon as late this year.Learn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

Hi everyone, it's Matt Kaplan, host of Planetary Radio, back with another Planetary Radio Extra, online-only edition. Special extended conversations this time, looking at a project that is near and dear to all of us at the Planetary Society, and apparently to many of you, it's LightSail. So we have the two best people on staff to talk to about that. Bruce Betts, you know and love, the Planetary Society's Director of Science and Technology. As such, he works on all of our projects, monitors them, contributes to them, and that includes the LightSail project, which he's quite involved with. Bruce, welcome. Thank you. Joining him is Jason Davis, Digital Editor at the Society, who we go to for stuff related to human and commercial spaceflight. But Jason is also our embedded reporter, as we have said in the past, in the LightSail project.

So they come at this from two different angles, and it'll be great to have both of their viewpoints. Jason, welcome also to you. Hello, Matt. Good to be back. to you. Hello, Matt. Good to be back. Bruce, give us just an overview, first of all, for those people who've only just emerged from a cave and aren't aware of LightSail or its successes so far. I have questions for the people who came out of caves, but that's a different issue. Different show. Different show. So LightSail is a Planetary Society project, and it is all about solar sailing. So using the pressure of light as a spacecraft propulsion method. Light's pushing on us all the time.

It's just a little tiny push, so normally we don't notice it at all. But if you put a big reflective mylar sail or something similar in orbit with a small spacecraft, then the light push actually becomes significant. And the Planetary Society flew a test mission several months ago and successfully deployed a solar sail and tested out the systems and learned a lot. And that was in a low Earth orbit where there was still a lot of atmospheric drag, so it was not solar sailing. But we're preparing for later this year a second flight where we will go to a higher orbit and actually try to demonstrate controlled solar sailing, so using the sun's light pressure to adjust the orbit. Can you say something else, a bit more detail about what your role is in the project,

Bruce? I am the program manager for the project, so kind of oversee and do exciting things like contracts and then oversee the project of which we have lots of people and organizations working on it and on the engineering side and design and test. I should mention also to envision this spacecraft, it's only about the size of a loaf of bread. It's five kilograms in size. It's in what's called a CubeSat, a 3U CubeSat. So these are very commonly used for Earth orbiting missions, particularly by universities, but more and more by NASA and others.

And so we're trying to develop solar sailing propulsion as a method you could use to actually, without carrying fuel, really change the orbit, use these on interplanetary trajectories and such. So the light sail focus is not only about solar sailing, but solar sailing using these small spacecraft CubeSats. And Jason, before we go any further, a lot of these basics, if people want more detail, only about solar sailing, but solar sailing using these small spacecraft cube sets. And Jason, before we go any further, a lot of these basics, if people want more detail, if they want to see great images, there's a place they can go, right? Yeah, we have a dedicated light sail website at sail.planetary.org. You can find all of the history of the project there, images, videos, and also our regular blog posts and updates. Jason, as we speak, your two most recent blog entries, another great place to follow what's

going on with the project, were January 26th and January 29th of this year. We're just a few days beyond that now. I want to start with what you wrote about on the 26th, and that had to do with, well, what I'm going to call the new and improved light sail. Is that fair? I mean, are we looking at a better spacecraft than we saw the first time around? Well, if you ask the engineering team that question, I think you're going to get a resounding yes. That virtually no subsystem has gone untouched in one way or another. They've really overhauled a lot of the software that controls all the subsystems and made a few hardware tweaks as well. But the software is one of the things that has really kind of underwent this complete transformation. For instance, when LightSail was in orbit and it gives us these little telemetry

chirps, these radio beacons that contain information about the spacecraft. On the first mission, we had about 80 odd lines of telemetry that told us how LightSail was doing. That's been almost tripled for this second mission. So we're going to have a lot more information about what the spacecraft is doing, which will come in handy if it runs into any problems, and the team will just have better insight into what's going on in space. Bruce, when an upgrade like this is made, it's quite a process. I mean, after all, this is rocket science. It's really pretty complicated when you want to make any kind of change to the software, isn't it? It is, and it's also risky. So remember, we're working in a spacecraft environment where you can't just jump out there and fix something in orbit, to state the obvious. And so the whole key in my mind and people who work on spacecraft is testing. So you make a change or you find a problem, whether with the first mission or in

your testing, you find a problem, you fix it, you develop the software, and then you test as much as you can. And so that's kind of where this light sail spacecraft is in the process, is it's all built and constructed. And in the last few weeks, we've begun the testing process. The individual components have been tested, but now the whole system's getting various tests that I'm sure we'll talk about, because you need to wring out the problems to make sure you find them on Earth rather than in space. Yeah, that's exactly where I want to go next. Jason, you wrote about in your January 26 blog at planetary.org, the ORT. Tell us what that was about. Yeah, ORT stands for Operational Readiness Test or testing. This is when the team

sort of takes the flight software out for a spin and pretends that the spacecraft is in space. They're getting data from it, and they need to perform a few key functions on board the spacecraft. The way they do this, they have a clone of LightSail called BenchSat, and it's kind of a deconstructed version of LightSail that is mounted on this piece of acrylic. And they turn it on, and it starts chirping just like the real light sail would chirp in orbit and they simulate a series of ground station passes. They all get on a phone bridge, the team gets on a phone bridge and it sounds very much like, I was impressed the first time I heard this during the test mission, it's like you're listening into

the flight loop at Mission Control Houston or something like that. Very professional and rigid. If you speak, you identify your subsystem area and who you're talking to. So you get these lines like, mission, this is flight. And the person responds and says, go ahead. They watch the spacecraft fly overhead, or in this case, BenchSat is just sitting there in the laboratory chirping. They get the data down from that. In a few minutes, the ground passes over, and they have small teams that are assigned to each subsystem of the spacecraft. So somebody's going to look at the power data that comes in. Somebody might look at the temperature data that comes in and so on. Everybody reports into the mission manager and tells him, in this case, Dave Spencer, what they're seeing.

And the pass is over and we take it from there. And then they go on to simulate some other critical functions like deploying the solar panels and deploying the solar sail itself. What these simulations allow them to do is find out not just any problems in the flight software itself, but are there any procedural changes that need to be made? For instance, I think during this test, there was a question of what order the commands should be sent to the spacecraft to arm and then deploy the solar sail. And then there was some little quirk around that that they needed to correct. So it's a dry run deploy the solar sail. And then, you know, there was some little quirk around that that they needed to correct. So it's a dry run with the new software to really iron out any

problems. One of the most fascinating things that you wrote about, to me anyway, you touched on there, but I want to emphasize this. This bench sat, so-called, sort of an exploded light sail spread out on the piece of acrylic. It's actually transmitting to a ground station, right? Yeah, yeah. It's really neat. We see this process in the laboratory. It's the exact same process that it will use when the spacecraft is actually in space transmitting.

So Cal Poly's antennas are receiving this signal from bench sat. The only difference is it's sitting in the same building versus flying overhead. And they even have, at Cal Poly, a radio receiver tuned to that specific frequency so that when BenchSat does one of its little telemetry chirps, there's a burst of audible static in the room, and that tells you that the spacecraft is transmitting. So that's just kind of one of those cool little things that they've done to add to the ambiance of

their mission control center that they have. Bruce, the testing is not done. We're going to get to what's coming up next, but what's your assessment of sort of the status, of what you've seen so far? Not just the performance of what we now know is LightSail 2, that is the official name, but of this team. Very good, very professional team with elements from Dave Spencer at Georgia Tech as the project manager and mission manager and Ecliptic Enterprises doing a lot of the integration and test and Cal Poly, Boreal Space, NX Track, all sorts of people involved. It's a fairly big team for a small spacecraft, but they're very professional. The testing, you can look at two ways.

We're finding problems, which can be disturbing. But on the other hand, it's exactly why you're testing. And so all of the engineers obsessively note every problem, and each of them is being worked on and try to ferret out fixes. And in general, like with the deployment tests that have been done, the sale deployed, but there were several minor glitchy things found along the way that are being worked. So that's why we'll be doing another round of deployment tests after corrections are made. And so basically just keep testing, find issues, fix issues, test, find, fix. Let's talk a little bit more about this deployment test. I was

surprised when I read that the actual deployment of the sails that was done on this amazing table on January 28th was the first time that had actually been done in a lab for quite a while. Bottom line is things worked the way you want them. The key test, the sail deployed, the booms deployed, and the boom tests, they're just minor things that need to be worked out and fixed, and that process is already underway. Remind us of this innovative technology that actually does the work of extending the sails. We've got four booms that extend outwards. They're kind of like tape measure material, but fancier. and a custom-made motor extends those booms over the course of a couple minutes out to four meters in length, each one of them.

Each set of two booms extends a triangular mylar panel. And so you end up with these four triangles of mylar that are extended. And it's got various things in the software so that if there's an issue, they can retract and start extending again, and it detects issues going on. But that's the basic concept. Jason, you wrote about this deployment stuff. It has to do, in fact, with some of the software improvements that have been made. And it also made me think of one of the most exciting moments during the flight of the first light sail, light sail one. And that's when we got the word that the motors were turning, that the sail was actually

being deployed. We saw a little counter incrementing. Yeah, it's kind of a dimensionless counter. So meaning when I say dimensionless, it doesn't really correspond to inches or an actual physical measurement like that. But there's a number in the telemetry that increments as the motor spins. When they did the deployment test up at Cal Poly, we saw, as expected, that this motor count started incrementing from zero all the way up to about 134,000. That's just what we saw during the test mission in space. There was this moment of tension where during the ground pass where we commanded the sail to start deploying, the pass was about half over and the team wasn't sure if the spacecraft had received the command to deploy the sail or not. It was about to go out of range for the day.

And then all of a sudden we started seeing those numbers going up and we knew that something on board the spacecraft was actually happening. So it's one of our favorite lines of telemetry. We want to see that number go up. It tells us good things are happening. It was a very exciting moment. Okay, what is the next big milestone, or I guess the science guy would have me say kilometer marker, in the testing, the prep of this spacecraft, LightSail 2? Well, they're going to regroup, as Bruce said, all these little minor issues that came up during this first sail deployment test. They're going to regroup, address all of those, try to find a resolution on all of those items. And then they'll do an intermediate deployment test kind of to verify that they've rung out all of those issues, boom deployment and assail deployment. Assuming that all goes well, they'll be ready to move on to what's called a day-in-the-life test. And that's where they simulate all of the key mission phases,

just like I was describing with BenchSat, only this time they'll do it with the actual flight unit. So they will command the solar panels to deploy. So they'll actually tie the solar panels up and verify that they've sprung away from the spacecraft, go all the way through to an actual sail deployment, just like they would do in the mission. So it's kind of an end-to-end test of the spacecraft. Bruce, when is that currently supposed to take place? Roughly mid to late March. So things are definitely moving along. And if the DITL goes well, then what? Then the spacecraft gets packed up, Bruce? Assuming one's happy with the results from the day in the life test, then the spacecraft gets packed up and shipped nominally

to Georgia Tech for incorporation and integration with their spacecraft that they're building called Prox-1 that LightSail, different than the first mission, LightSail in this case will actually be inside Prox-1. And Prox-1 will be deployed first and then LightSail will be deployed from within Prox-1. And Prox-1, it's things that it's trying to do is proximity operations around another spacecraft. So if all goes well, we'll get nice imagery and tracking from Prox-1 that will kind of stalk LightSail during the process. So it's a little bit of Russian doll action here.

You've got the rocket, you've got Prox-1, and then LightSail, which will pop out of it. And then what is this PPOD technology, Jason? Can you remind us about that? Poly PicoSatellite Orbital Deployer. Easy for you to say. Easy for, yeah. And that's the word poly in there comes from CalPoly, which helped to standardize some of these formats for standard CubeSat sizes. One of these Peapod deployers are essentially just a little shoebox that's just slightly bigger than a three-unit CubeSat, which LightSail is. And it has a coiled spring. So LightSail kind of fits into this Peapod on top of the spring.

The door kind of closes on it to hold it in place. At the right moment in orbit, that little door just springs open, and the spring just pushes the light sail out into space. So that whole peat pod unit will be mounted inside the PROX-1 spacecraft. Bruce, this will all happen, we hope, but it's all got to get up into orbit first. How's that going to happen? PROX-1 with light sail inside. Inside a rocket, the rocket will be a SpaceX Falcon Heavy, and this will be the second flight of the Falcon Heavy, and it will launch along with

the main payload and a bunch of other small satellites that will be spewed out on orbit. What's the current outlook for that launch? spewed out on orbit. What's the current outlook for that launch? Well, right now it's officially scheduled for September of this year, 2016, but because of various delays in the rocket process, it's quite possible that will slip, but everything we're doing is striving towards a September launch. So we'll be ready no matter what. We will be ready. Jason, give us an idea of what we'll be going on back down here on the ground, just sort of the coverage that will allow people to participate in the flight of LightSail 2. We would really like to do what we did last year and improve upon it. So we'll have regular blog coverage and we'll also be encouraging amateur radio operators

to tune in to the spacecraft signal and capture packets and submit them to us. We're working on that aspect of it now. Cal Poly is working on some software packages that might streamline that process, so stay tuned for that. We also hope this time around to have our dashboard up and running that shows some real-time telemetry from the spacecraft on our website. So you'd be able to log in and see at any given point the last time we heard from LightSail what all of its sensors were up to. In case one is interested in what the temperature on a random solar panel in the middle of low Earth orbit is reading. low Earth orbit is reading. And remind us once again of where people will be able to find that dashboard and even before launch, where they can go right now to keep track of what's going on with the mission. Sure, it's sail.planetary.org. And we'll be following LightSail all the way through

these upcoming tests. We'll be live on site for the day-in-the-life test and for integration at Georgia Tech into Prox1. So we'll have all the coverage there. Bruce, what will you be up to during that Day in the Life test, and then later during the actual flight? I will be at the Day in the Life test up at Cal Poly San Luis Obispo, and then during the flight I planned on being somewhere in the South Pacific on a beach, sipping juices. somewhere in the South Pacific on a beach, sipping juices.

No, I'll actually plan to pay attention to the mission. Wringing your hands, no doubt. All right, well, I will be ready for the celebration. I better knock on wood before I talk about that. Of the sort that we had after the flight of LightSail 1. Gentlemen, thank you very much. Great talking to you. And maybe we can do this again, either, well, maybe not during,

but after that day in the life test, which is now maybe just a month and a half or so away. Thank you, Matt. Sounds good. Thanks, Jason. Thanks, Bruce. Bruce Batts is the Planetary Society's Director of Science and Technology.

So LightSail is just one of the many projects that he monitors and contributes to, in this case, as the program manager. All this happens when he's not creating random space fact videos or teaching his online astronomy course or goofing around with me in Planetary Radio's What's Up segment. Jason Davis is a digital editor at the Planetary Society. In addition to his work as our embedded reporter in the LightSail project, he's our go-to guy for news about human and commercial spaceflight.

He had a distinguished and busy career doing print and online aerospace and astronomy journalism before we grabbed him for our staff. Someday soon, you really ought to check out his terrific documentary, Desert Moon, narrated by astronaut Mark Kelly. And I'm Matt Kaplan, the host of Planetary Radio. Hope you will join us on a weekly basis for our recap of what's going on around the solar system and beyond. We'll be back with another Planetary Radio Extra before long as well, probably talking about the NASA budget proposed for 2017 with our Director of Space Policy, Casey Dreyer.

Thanks for listening.