Eyes on Earth Episode 87 - Landsat 5's Significance, Part 1

JANE LAWSON:

Hello, everyone, and welcome to another episode of Eyes on Earth. Our podcast focuses on our ever-changing planet and on the people at EROS and across the globe who use remote sensing to monitor the health of Earth. My name is Jane Lawson, and Iíll be hosting todayís episode, where weíre talking about the significance of the fifth satellite in the 50-year-old Landsat program. Designed to last three years, Landsat 5 launched in 1984 and overcame serious obstacles along the way as it transmitted data for nearly 29 years, until the launch of Landsat 8 in 2013. Landsat 5 set a Guinness World Record for longest operating Earth observation satellite. And in October 2022, its flight operations team won the 2020 Group Pecora Award during the 22nd William T. Pecora Memorial Remote Sensing Symposium. The satellite is significant because of its length of service and its contribution during that time of millions of scenes to the Landsat archive at EROS. Itís also significant in research because studies of land change over time often start with the mid-1980s to take advantage of Landsat 5ís convenient-to-use Thematic Mapper sensor data. One of our guests today is Steve Covington, who accepted the Pecora Award on behalf of the Flight Operations Team and shared his memories of the beginning of Landsat 5ís life, while he was an engineer at EROS, and at the end of the mission, when he was the Landsat 5 flight manager. He is here to talk about the significance of Landsat 5 and is joined by Jeff Devine, who was the lead operations engineer for the mission. Steve now works for the Aerospace Corporation and is currently the principal systems engineer for the USGS Headquartersí National Land Imaging Program, which, among other things, funds and oversees the Landsat development, flight and archiving at USGS. Jeff works at NASA Goddard Space Flight Center for KBR, leading the GLAST/Fermi Mission Flight Operations Team. Steven, Jeff, welcome to Eyes on Earth.

STEVE COVINGTON:

Thanks for having us here.

JEFF DEVINE:

Nice to be here.

LAWSON:

Steve, do you want to start out by giving us a bit of background of the Landsat 5 flight operations team and your own involvement?

COVINGTON:

Sure. My involvement with Landsat 5 actually started with watching the launch, sitting in a conference room at EROS back in 1984, snow was on the ground, as I recall, and worked with the data initially while I was out at EROS. And then when I left EROS in the middle, late eighties, I didnít have much to do with it until coming back to work with USGS during the development of Landsat 7 in the mid-nineties. I was the liaison between NASA and the USGS during that timeframe, and as part of my work, I worked with NOAA [the National Oceanic and Atmospheric Administration], who was overseeing flight operations for Landsat 5 on behalf of the government. And so I was involved in the monthly briefings with that, and that kind of reintroduced me to where things were at 10, 12 years after Iíd left working with it. Then after the launch of Landsat 7, and I was flight systems manager for that mission, about a year later or so, EOSAT [Earth Observation Satellite Company] gave Landsat 5 back to the government. And so at that point in time, both myself and Ron Smilek were the flight systems managers for that mission for Landsat 5. And that brought me right back into it. And I stayed with it until we pushed the button, turning it off in 2013, June 5th.

LAWSON:

How did your previous work at EROS contribute insights that might have helped you with your later Landsat work?

COVINGTON:

The biggest contribution of working at EROS earlier was it got me the job later to do work on Landat 7, and so that was all good. But it also meant that I had a very good working relationship with the staff at EROS, and as you may know, EROS is the project office for Landsat. So all the Landsat mission development, production, archiving, distribution all happens through management at EROS, and a lot of the work done at EROS. And so even though the missions are actually flown out of NASAís Goddard Space Flight Center with the USGS crew, because itís 1,500 miles away, it was really important, I think, especially in those early years, to have that relationship with R.J. Thompson and Tracy Zeiler and Kristi Kline and Jim Lacasse, Brian Sauer and others to have a level of trust necessary for USGS to feel confident to fly these missions at all, let alone 1,500 miles away. So EROS has been and the USGS in general have been so supportive of the Landsat program and what itís done. Of course, they started archiving data back in the early missions in the early seventies. And so having the opportunity to work with them from a distance from Goddard to EROS was very important. And the crew there really jumped on the bandwagon in support for flight operations, but secondly, are second to none in the world, really, were renowned for their work as a ground station and archivist of Earth observation data. So itís been great working with them all along.

LAWSON:

Jeff, do you want to add your involvement in the mission?

DEVINE:

Sure. My involvement began as Landsat 5 entered its 23rd year of operation. I was happily working a very secure position at NOAA, operating the POES [Polar Operational Environmental Satellites] satellite constellation. And I was approached by a former supervisor of my company who told me that we had just won the contract to operate Landsat 5 and offered me the job of leading the engineering team. Interestingly enough, I had just gotten a new boss at NOAA who had just left Landsat 5 team because he thought the spacecraft was too old and sick and wasnít going to last very long. So he jumped onto a new project, and I didnít take that hint. And I agreed to take the position on Landsat because it came with a nice raise and a significantly shorter commute. Five days later, that spacecraft, Landsat 5, had a major anomaly that looked like would be the end of the mission. And Iím sitting there just not knowing anything about whatís going on, except I wonder if NOAA will take me back. But I stayed on to lead the team of four other engineers who did almost all of the planning, execution and analysis activities for the mission over the next six years.

LAWSON:

So now we know how the life of Landsat 5 played out, lasted nearly 29 years, and its key role in maintaining that unbroken record of Landsat data. But did you have any sense of how significant the satellite would turn out to be in the long run?

COVINGTON:

I think I did from the start because I worked with it right from the start. And let me just expand first on what your point was on the importance of Landsat 5 played in the life, extension and the continuity of land, the Landsat systems, the Landsat observations. Launched in 1984, Landsat 4 has had problems, so Landsat 5 really carried the water to a large extent for global observations and survey. Landsat 6 failed to achieve orbit in 1993, so that meant Landsat 5, which was already well over - at that point in time, it was 9 years old. It was a three-year design life. So Landsat 6 was meant to replace that capability; that failed to reach orbit. So Landsat 5 had to continue on at least until the launch of Landsat 7, which wasnít until 1999. And then in 1999, Landsat 7 launched, and for a couple of years, we had all this great coverage for both Landsat 7 and Landsat 5. And then Landsat 5 rejoined the government ranks and right after that, within a couple of years after that, Landsat 5, Landsat 7, excuse me, suffered a failure of its scanline corrector, which meant its data was now somewhat compromised, still very useful, highly calibrated, but somewhat compromised in the way it looked. And so Landsat 5 became even more important in terms of its collecting. And at this point, like Jeff was saying, itís 20-plus years old and getting older every day, with all these various problems that were creeping up. So the continuity that it provided, running until 2013, was really amazing and so important because it was in 2013 that Landsat 8 launched, which brought in a whole new era of Landsat observations. Right from the beginning, Landsat 5 did all these really amazing things. It was the first satellite to really map the deforestation occurring in the Amazon and in the Congo regions and put a face, if you will, to the problem of deforestation that was occurring. It was the first satellite to image Chernobyl, the after, after that power plant in the Ukraine was crippled by that explosion. It was Landsat 5 that took images that we had images both before and after, so you could see the cooling pond, which normally was hot at the output of the east of the nuclear plant, and then cool as it went around a circle; that became all one temperature. We were using the thermal data from Landsat for that, and that showed that the reactors are no longer operating. And, of course, thereís this big black hole where one of the reactors was. So that was pretty amazing that it did that. But all through time and through all the collections that it did, it became the link between the first images of 1972 and the first images of Landsat 7 in 1999. If it wasnít for Landsat 5, there would have been a very large break in that observational continuity that we work with to this day, for climate change research and in agricultural sciences and all these other great applications.

LAWSON:

Jeff, did you have anything to add?

DEVINE:

For me, I understood the significance because this satellite was flying for 23 years before I even joined the team, and that was 10 years longer than any other satellite I had ever operated to that point. But it was more personal for me. I had, I felt like Landsat 5 was something that I was fated to do. The reason being, when I first started my career in the space industry in the early 1980s, I was operating the Air Force satellites in Sunnyvale, California. I noticed a large framed aerial photograph of the San Francisco Bay area for sale in an art gallery. And I really loved that picture. And back then it cost $100, which you can imagine is probably about $1,000 for today. And I liked it so much that I bought it right then and there and hung it in my living room for a couple of decades. That photo was taken by Landsat 5, which at the time I bought the picture meant nothing to me at all. And 20 years later it was me taking the same pictures, using that same camera.

LAWSON:

Thatís wonderful.

COVINGTON:

Thatís kind of how I feel, because I remember very clearly watching the launch of Landsat 5 back in 1984, just thinking, well, this is pretty darn cool, and Iíll get to work with this data. Had no idea that Iíd end up being there to help push the button that turned it off. 

LAWSON:

Do you want to share with us briefly, Steve, how was it able to last so long?

COVINGTON:

So, obviously good genes help. So the designers, the engineers and the technicians that built the satellite obviously did it right on Landsat 5. So that always helps. But probably if there is one word that you could use is fuel. And thereís lots of, there are lots of answers to the question of why it lasted so long. But if it did not have the fuel supply that it had, it never would have survived. The reason they had so much fuel is because it was launched not only with its three normal tanks but had this large auxiliary tank, that itís, the purpose of it was to lower the orbit when it was launched. It was designed to be shuttle retrievable and serviceable. And there was going to be a polar orbiting shuttle that would fly up into a polar orbit. Landsat 5 would use this external fuel, this auxiliary tank, to lower its orbit down to 450 kilometers, so that it could be captured by a grappling arm on the shuttle, brought into the bay, serviced and refueled and sent back up again. That was the plan. But the polar orbiting shuttle never occurred. They never got to that point with the shuttle program. So all that extra fuel that was to lower the mission was available for us to use to maintain the missionís orbit, which proved critical again, which is what I was talking about in terms of observational continuity. We needed that mission to last as long as it did, and without that fuel, that would not have lasted. Now, we ran out of fuel with the primary tanks around 2023, excuse me, 2003 or so, and the mission would have been done then; we would have been out of fuel. So that auxiliary tank made a huge difference.

DEVINE:

And just to add to that, at the end of the mission when we deorbited, we had enough fuel for another 10, 15 years, I think.

LAWSON:

Do you want to describe any other challenges or big worries that you had while you were on the team? 

DEVINE:

The moment of my biggest worry, and I think Steve and I, Steve, you and I looked into each otherís eyes when this happened and thought it was the end.

LAWSON:

Our next podcast episode, weíll continue this conversation with Steve Covington and Jeff Devine. Theyíll describe the roller coaster ride that Landsat 5 gave their team, including the moment where they were sure they had lost the satellite. Check out our EROS, Facebook and Twitter pages to watch for our newest episodes. You can also subscribe to us on Apple Podcasts and Google Podcasts. This podcast is a product of the U.S. Geological Survey, Department of the Interior.