NASA’s Laser Communications Relay Demonstration Principal Investigator Dave Israel discusses the dynamic power of laser communications technologies.
As science instruments evolve to capture high-definition data such as 4K video, space missions will need expedited ways to transmit information to Earth. NASA’s Laser Communications Relay Demonstration (LCRD) will showcase optical communications technologies that will further empower missions with unprecedented data capabilities.
In this episode of Small Steps, Giant Leaps, you’ll learn about:
- How laser communications can empower more discoveries
- The impact of LCRD on future missions
- The LCRD Guest Experimenter Program
David Israel is the Principal Investigator for NASA’s Laser Communications Relay Demonstration (LCRD) and the Division Architect for the Exploration and Space Communications Projects Division at Goddard Space Flight Center. As architect, Israel envisions the future of space communications, developing the capabilities and technologies needed to develop a solar system internet. He has led various space communications projects, including systems that provide links to Earth’s north and south poles, and implementations and demonstrations of space internetworking. Israel has led the development of various Space Network/Tracking and Data Relay Satellite Systems (TDRSS) operational systems and has been the principal investigator for multiple communications technology activities concerning advanced space communications concepts and networking protocols, including the LPT CANDOS experiment on Space Shuttle Columbia (STS-107) and Disruption Tolerant Network demonstrations on the Lunar Laser Communications Demonstration. He received a bachelor’s in electrical engineering from Johns Hopkins University and a master’s in electrical engineering from George Washington University.
David Israel: The optical links will be the equivalent of the transatlantic fiber cables that run between continents. There’ll be these optical links that provide that high bandwidth trunk line in between the Earth and the Moon, or between the Earth and Mars or Earth and wherever.
A primary objective of LCRD is to not just learn and understand how to use this technology operationally for NASA use, but it’s also for commercial use and any other applications.
Deana Nunley (Host): Welcome back to Small Steps, Giant Leaps, a NASA APPEL Knowledge Services podcast where we tap into project experiences to share best practices, lessons learned and novel ideas.
I’m Deana Nunley.
Radio waves have been used successfully in space communications since the beginning of space exploration, but enhanced communications capabilities are a necessity as space missions generate and collect more data.
Optical communications will provide significant benefits for space missions, including as much as 100 times more bandwidth than radio frequency systems.
NASA’s Laser Communications Relay Demonstration – planned for launch in the near future – will showcase the unique capabilities of optical communications. And LCRD Principal Investigator Dave Israel is here to talk with us about the mission.
Dave, thanks for joining us.
Israel: I’m excited to be here.
Host: Can you give us a quick overview of the Laser Communications Relay Demonstration?
Israel: Sure. As the name implies, it is a demonstration of using lasers to perform relay communications. And by relay, means we have two laser communications terminals, or optical communications terminals, which are telescopes connected to modems using laser beams to then set up laser links. The two separate optical terminals allow us to connect to one user using the laser, and then relay that data back to Earth through the second laser communications link.
Our mission will be on a spacecraft, the STPSat-6 spacecraft that will be at a geosynchronous orbital location. In the beginning, we’ll have two ground stations, one in Hawaii and one in California. We’ll have an optical link connected from one of those ground stations up to space, and then we will take the data off of that link and relay it back down to the other ground station.
Host: What are the key objectives of LCRD?
Israel: LCRD is beyond a straight technology demonstration mission. It’s more of an operations demonstration mission. There was a highly successful mission that flew in 2013 on the LADEE spacecraft to the Moon, and that was called the Lunar Laser Communications Demonstration. That was a straight technology demonstration. There were people that had some doubts about whether or not we would be able to successfully connect an optical terminal moving in space with the terminal here on Earth. That mission demonstrated very quickly the two terminals could find each other.
We were able to transmit through the atmosphere and do the highest data rate ever to and from the Moon and do it all by lasers. It was very successful except by design it was short-lived because the LADEE spacecraft that it was on was designed to after a period of taking measurements to actually crash into the Moon and make some measurements when that happened. Our laser communications terminal was still working, but then it was crashed into the Moon. So the amount of experience that we got with free space optical comm was measured in hours for that mission.
So, though the technology has been proven with LCRD, we’re going to have two years of operations and experiments on orbit to do long-term demonstrations and characterization of how optical links work through the atmosphere, refine our models of weather and atmospheric effects, and also just gain experience of operating optical links in a manner that we can try different things. Because it’s a demonstration we’re not supporting operational users yet, so we’ll be able to collect the data from experience that will allow us to come up with the requirements and the designs and understand how once we use this operationally, we will know how to do it.
We’ve got 50, 60 years of experience of how to do communications using RF links, or radio waves to and from space. There’s a lot that we do now that maybe some of us don’t even know why that’s the standard way we do things, but a lot of the things that we do were gained through experience over the years. And we’re getting that first experience now with optical comm through LCRD.
Host: So, we’re seeing this shift from radio waves to optical communications.
Israel: Yeah. The big shift from radio waves to lasers and a good trick question to ask your friends, or I like to use this on a class of things, is which signal gets faster someplace, a laser comm link or a radio wave link? And really the answer is they happen at the same time. They’re both going at the speed of light.
The reason why people think of lasers as being faster is because we’re able to carry higher data rates on those using the laser wavelength as our carrier frequency. Having that smaller wavelength gives us the ability to send more data from a bandwidth point of view. Also the way the physics works out is that, and people use the term laser as like being laser-focused on something, that focus, that power all concentrated in a smaller beam is what allows you to deliver more power to the thing that you’re trying to communicate with, which then means that you’re not wasting your energy sending communication signals to people that aren’t listening, and it makes it a more efficient way to communicate as well.
So, the end result of those factors gives you the benefit of not just higher data rates, but you can have smaller systems. From a size, weight, and power point of view, you can have telescopes that are much smaller in diameter than the antennas that people are used to seeing on Earth to communicate with space or on spacecraft to communicate back with Earth.
Host: Let’s talk about LCRD experiments. How does the Guest Experimenter Program work and who can participate?
Israel: A primary objective of LCRD is to not just learn and understand how to use this technology operationally for NASA use, but it’s also for commercial use and any other applications. So we have our own experiments that we’re doing to emulate how we would use this to support an orbiting mission for us to, like I said, better calibrate and characterize the weather and atmospheric effects. We want to learn how quickly we can hand over from one ground station to another ground station, and how well we can predict based on weather forecasts, how the link is going to degrade. So those are our types of experiments.
But the Guest Experimenter Program makes it an opportunity for others to come in with, some examples would be from a science perspective, somebody saying, ‘I have this mission. It’s going to go out to a Lagrange point. And because of the benefits of laser comm, we think we want to use it, but we’re not sure because of the weather and atmosphere, whether or not we’re really going to get all the data that people think. We think the link’s going to be down all the time.’ So, we can configure our system to match that scenario. Even though the link will be coming from geo orbit, all the weather and the atmospheric data will work.
But then there’s commercial type applications. Optical links from space to ground have commercial benefits. One benefit is what I described, that you can carry a higher data rates. Another benefit is that the optical communications aren’t subject to the same frequency and spectrum regulations that RF frequencies are, so there’s some advantages there as well. There may be some commercial provider, commercial interests that may want to better understand how they would be able to operate, or depend upon, or specify space-to-ground optical link.
There’s a whole assortment of other categories. We have the ability to connect to other people’s modems or systems out at our ground station to communicate with LCRD. Of course, there’s quite a bit we have to go through to make sure it’ll be compatible and work it all out so that it can connect, but that’s possible as well. So there’s a wide range of things possible, and the program is open to anybody. On our LCRD website there’s a link to send an email to inquire further. There’s also a document called Introduction for Experimenters that gives an overview and starts to give more ideas of what types of experiments would be possible.
Host: Sounds good, and we’ll post a link in our related resources.
Israel: That’s great.
Host: Yeah, no problem. Dave, what’s the plan for daily operations, especially from an engineering perspective?
Israel: Once we’re on orbit and the payload is checked out, so that’s after a couple of months, then there’s a virtual handing the keys over to me and the experiment team, and then we will have our prioritized list of our NASA experiments and the guest experiments. In advance we’ll have it planned out, and a schedule will be given to the ops team to run the particular experiments. There’s some experiments that maybe the experimenter will want to be watching or involved in, and it’s more interactive. There’s other types of experiments where it’s like run the link in this configuration for a certain number of hours or days, and tell us what happened.
The ops team will step through each of these experiments. We’ll have primary and backup experiments, so if it’s an experiment that depends on the two ground stations and one ground station is cloudy, then there’ll be backup plans. Currently we’re planning a 40 hour a week running the experiments and activating the links. Those 40 hours are not going to be the same 40 hours every day, because it’ll shift in time because we want to characterize the performance at all times of day through all the seasons. So, we’ll be keeping the links very active and configuring in different ways throughout the whole experiment period.
Host: With so much going on and so many experiments, how will you know that the mission is successful?
Israel: That’s a good question. Success is measured in different ways. The very NASA way that we do it is that we have our minimum and full success criteria that we have where there’s a certain number of experiments for a certain amount of time, and identified experiments that we need to do to claim minimum success and full success. But really for me, the thing that’s less quantifiable but how I’ll know we’re successful is when I start to see either commercial service providers or any other commercial entity, or NASA missions, or any place where future systems are being developed and then put into operations, and they’ve got that last bit of confidence that they need through either data or just working with us or just seeing our success, that it then leads to optical comm not being a NASA technology demonstration anymore, it’s an everyday way that people are operating. Once I start to see that happening, then that’s when I’ll look back and say, ‘Yes, it really was successful.’
Host: And following on with that thought, what do you envision as the impact of this mission on future space exploration?
Israel: I think that grand vision of what I think it will look like to be successful, I do have high confidence that that will happen. One of the great things about this Technology Demonstration Mission program part of NASA’s STMD portfolio is the idea that there are certain technologies that are maybe past the technology demonstration point, like a pure, will the technology work, but they’re still at a stage where folks for whatever combination of reasons, aren’t comfortable to use them operationally, and that’s this gap that missions like LCRD are for.
Once we have our success and we do it, then I think it’ll get things over the hump, so that then the impact on future NASA missions will be things like what comes after JWST. For example, those science missions not only will the scope of their science grow, but they’ll know that they can get a much higher data rate down, so they’ll just be able to collect a whole lot more science. We’ll just start to see that happen.
With the Lunar and Mars Exploration, the optical links will be the equivalent of the transatlantic fiber cables that run between continents. There’ll be these optical links that provide that high bandwidth trunk line in between the Earth and the Moon, or between the Earth and Mars or Earth and wherever. So I think the impact on our NASA plans and goals will directly follow once we get this confidence boost and increased knowledge.
Host: We’re all looking forward to LCRD. This has been very informative. Dave, thank you for taking time to join us today on the podcast.
Israel: Thank you. It’s great to be here. I’m very, I guess, excited is the word that keeps coming up. So yes, thanks.
Host: Do you have any closing thoughts?
Israel: I guess my closing thoughts go really to talking about all the people. I just want to thank and acknowledge all the many people that have done the hard work to make this a reality. I joke to people that my job as a PI is like to draw cartoons and pictures and imagine things, and it’s lots of other people that are doing the hard work to make it really happen. So, I just want to thank those people and tell them how appreciative I am of them.
Host: You’ll find Dave’s bio, links to related resources and a transcript of today’s episode at appel.nasa.gov/podcast. If you want to hear more about LCRD and space communications, check out another NASA podcast, The Invisible Network. And speaking of other NASA podcasts, we want to send congrats to Gary Jordan and our friends at Houston, We Have a Podcast on the release June 18 of their 200th episode. Great work! You can find these and other NASA podcasts at NASA.gov/podcasts.
As NASA gears up for the Artemis I mission around the Moon that will pave the way to send the first woman and the first person of color to the lunar surface, we have an important task for you (yes, you!).
Artemis I will be an uncrewed flight test of the Space Launch System rocket and the Orion spacecraft ahead of the first flight with crew on Artemis II.
There won’t be any astronauts onboard Artemis I, but there will be a very important crewmember — the Moonikin!
A Moonikin is a manikin, an anatomical model that simulates the human body and is commonly used in training for emergency rescues, medical education, and research. The Moonikin on Artemis I will be equipped with two radiation sensors, and sensors in the seat – one under the headrest and another behind the seat – to record acceleration and vibration throughout the mission as Orion travels around the Moon and back to Earth. Data from these and other sensors inside the spacecraft will help NASA understand how to best protect crew members for Artemis II and beyond.
But the Moonikin is currently missing something incredibly important — a name!
We have eight names to choose from, but only one can win. Every other day starting Wednesday, June 16, we will be asking social media users on Twitter, Facebook, and Instagram, to vote between one of two names. The winners of each bracket compete with one another until the final showdown on Monday, June 28. The final name of the Moonikin will be announced on Tuesday, June 29.
So be sure to follow @NASAArtemis on Twitter, Facebook, or Instagram for a chance to vote on your favorite name! For more info, go to nasa.gov/nametheMoonikin.
We’re also interested in your suggestions for future topics on Small Steps, Giant Leaps. If there’s a guest or topic you’d like for us to feature, please let us know on Twitter at NASA APPEL – that’s APP-el.
As always, thanks for listening.