(on-screen text) Landsat 9: Contenting the Legacy
Matt Bromley: Absolutely. As a native Nevadan, we're aware of the value of water.
(on-screen text) Episode Two: Designing for the Future
Narrator: This is Matt Bromley. Understanding water scarcity? That’s his second nature. He's one of the key players tracking water usage in Nevada and the western United States from space.
Matt Bromley: Everything from public service commercials telling you to turn off your faucet while you're brushing your teeth to knowing which days you're allowed to water your lawn based off of whether or not you have an odd or even address. There's years where the water in the river is very, very low, and then there's years where it's really plentiful. And so we're really tied into that variability from year to year.
Narrator: For a state like Nevada, somewhere between 70 and 80% of the water in the state is used for agriculture.
Matt Bromley: And so if we can do better with managing irrigation water agricultural water, it goes a long way with water conservation.
Narrator: The Landsat program has had its eyes in the sky for almost 50 years. Remember how USGS and NASA teamed up, made a revolutionary satellite and launched into space? Yeah, that was great. The point is, Landsat’s success is due in large part to its forwarding-thinking tech. Each new generation produces better and better measurements. And you can’t conserve what you can’t measure.
Phil Dabney: Just in agriculture, the ability to look at the consumption of water... the economic value of Landsat to agriculture alone is several times the cost, or a few times the cost, of the entire system. And that's pretty significant.
Narrator: That’s Phil Dabney. A self proclaimed dinosaur, Phil has worked for Landsat since Landsat 7 back in the nineties.
Phil Dabney: It's always been about the detector, I actually had a bumper sticker that people tease me that only, uh, the nerds at NASA would understand. And that was "it's the detector stupid!" And that's been our limitation.
Narrator: The detector that Phil is talking about is basically the most important piece of technology on the entire satellite. It’s where light gets turned into data. In the early days, the detector was made out of just silicon, the same material you’d find in your smartphone camera today. Technological limitations prevented Landsat from seeing anything too far beyond the visible light spectrum. Fast forward to today, when our detectors span infrared frequencies. Landsat 8’s thermal sensor is so sensitive, scientists can calculate Earth’s temperatures down to a fraction of a degree.
Phil Dabney: The addition of thermal is a major addition. And then things came out of that like evapotransporation, the ability to estimate how much water the plants are taking out of the ground based on how well they can cool themselves by sweating essentially. And, and that's been used a lot in agriculture water managment.
Narrator: This detector seems to be a pretty big deal. But what does it do? I’m so glad you asked. There are two instruments aboard Landsat 9. So that means there are different detectors. Let’s start with OLI. When you’re building hardware for space flight, you have to keep it in a clean room to protect it from any dust that might block light …and OLI is all about light. Once in orbit, OLI collects sunlight reflected off Earth’s surface. The reflected light bounces between a few mirrors to focus the beam on a plane of detectors, all lined up in a row. The light passes through a set of filters, to separate out nine specific wavelength bands, in visible and infrared frequencies. Each band provides different pieces of information about the land cover. The second instrument aboard Landsat 9, called TIRS, is a little different. It collects the thermal infrared wavelengths, or "temperature signatures" emitted by the Earth itself. But to accurately calculate the temperature, the detector needs to be much colder than what it is measuring from Earth. So along with the lenses and the detectors, TIRS carries a condenser that cools the detectors down to 43 Kelvin. That’s -382 degrees Fahrenheit! To put it all together, let’s go to an engineer.
Melody Djam: The spacecraft is not just a piece of structure that holds this instrument. The spacecraft responsibility is to provide the juice or information or power that the instrument needs in order to function.
Narrator: Melody’s right. The detector may be the most important part of the spacecraft, but it’s far from being only tech on board. As the TIRS-2 Deputy Project Manager and systems engineer by trade, she understands first hand what kinds of life-support systems are required to keep these two instruments operational. Picture this: The entire satellite stands about 15 feet tall and is the length of a school bus. TIRS-2 and OLI-2 occupy about this much space. The rest is occupied by other critical systems that power the satellite, cool the instruments down, package the data, send it back to Earth, along with many other duties.
Melody Djam: And looking at the data and seeing the smile from the scientists that they’re getting the right data, that by itself is great, a great experience.
Matt Bromley: Yeah, so I don't know if you noticed, but I get kind of a smile when I start thinking of this Landsat data, because it is very unique. It's very special and it feels good to be part of work like this.
Phil Dabney: Yeah, it's being surrounded by people that can do, you know, failure is not an option, which is a famous NASA phrase. We can do that. We'll make it happen. [chuckles]
Narrator: It’s clear that Landsat tech is delivering on its promise to provide game-changing data. Landsat 9 represents the best of what NASA has to offer. But what happens when your satellite works so well that keeping up with all the information it’s sending back to Earth becomes its own monumental challenge?
(on-screen text) Coming Next…
Jeff Masek: You're seeing before your eyes, you know, how the environment of forest change, how agriculture changes, urban expansion, the whole, the whole thing, how the planet has changed over 50 years. So it's, to me, it's that historical perspective that I find really fascinating.
(on-screen text) Episode Three: More Than Just a Pretty Picture
Landsat is a joint program of NASA and USGS