NASA and United Launch Alliance deployed a new Landsat satellite in orbit Monday after liftoff on an Atlas 5 rocket from Vandenberg Space Force Base in California, marking the 2,000th launch from the West Coast spaceport since 1958 and extending a series of Earth observations used by farmers, urban planners, and climate scientists.
The Landsat 9 satellite is the next in a line of remote sensing satellites developed by NASA and the U.S. Geological Survey, providing a continuous, unbroken stream of imagery of Earth’s land surfaces since 1972.
The Atlas 5 launch team resolved minor during Monday’s countdown and gave the all-clear for liftoff of the 194-foot-tall (59-meter) rocket with the Landsat 9 satellite at 11:12 a.m. PDT (2:12 p.m. EDT; 1812 GMT).
Running on an automated countdown sequencer, the Atlas 5 fired up its Russian-made RD-180 main engine and hold-down restraints opened, allowing the launcher to begin a climb away from foggy Space Launch Complex 3-East at Vandenberg.
The kerosene-fueled RD-180 engine produced 860,000 pounds of thrust to drive the Atlas 5 rocket through the atmosphere, swiveling its dual nozzles to maintain control as the launcher headed south from the California coastline over the Pacific Ocean.
After surpassing the speed of sound, the Atlas 5 continued downrange until cutoff of the RD-180 main engine about four minutes into the flight. Seconds later, the expendable, single-use bronze booster stage detached to fall into the Pacific Ocean.
— Spaceflight Now (@SpaceflightNow) September 27, 2021
A Centaur upper stage ignited its cryogenic engine, fed by liquid hydrogen and liquid oxygen, for a 12-minute firing to give Landsat 9 enough velocity to enter a stable orbit around Earth.
The upper stage’s RL10 powerplant hit its marks, placing Landsat 9 into a near-circular orbit around 420 miles (675 kilometers) above the planet. After an hour-long coast over Antarctica and back north over Africa, the Centaur stage released the 5,975-pound (2,710-kilogram) Landsat 9 spacecraft at 12:32 p.m. PDT (3:32 p.m. EDT; 1932 GMT).
A few minutes later, the spacecraft, built by Northrop Grumman, extended its solar array to begin producing electricity for its mission, expected to last least five years. A ground station in Norway acquired the first signals from the spacecraft, confirming Landsat 9 was alive and healthy in orbit.
The Centaur upper stage’s mission wasn’t over.
Two more RL10 engine burns, each lasting about 10 seconds, reduced the rocket’s altitude for separation of four CubeSat rideshare payloads. The small satellites — two for NASA and two sponsored by the U.S. military’s Defense Innovation Unit — ejected from carrier modules on the Centaur stage, according to ULA.
One of the CubeSats, named CuPID, will study the interactions between solar activity and Earth’s magnetic field, probing dynamics that impact space weather. Another NASA-supported CubeSAT, known as CUTE, carries a tiny telescope to look at atmospheres on planets outside our solar system.
The two military-sponsored CubeSats were developed by an Austin, Texas, based company called CesiumAstro to test advanced communication technologies.
The Atlas 5’s first stage has shut down and jettisoned, and the Centaur upper stage’s RL10 engine has ignited for the first of four firings on today’s flight.
— Spaceflight Now (@SpaceflightNow) September 27, 2021
“Today’s successful launch is a major milestone in the nearly 50-year joint partnership between USGS and NASA who, for decades, have partnered to collect valuable scientific information and use that data to shape policy with the utmost scientific integrity,” said Secretary of the Interior Deb Haaland in a press release.
“As the impacts of the climate crisis intensify in the United States and across the globe, Landsat 9 will provide data and imagery to help make science-based decisions on key issues including water use, wildfire impacts, coral reef degradation, glacier and ice-shelf retreat, and tropical deforestation,” Haaland said.
NASA is responsible for spacecraft development and launch services on the Landsat program. The USGS is in charge of ground systems and the Landsat data archive, and will operate the Landsat 9 mission after it completes initial post-launch checkouts.
Landsat 9 will maneuver into a polar orbit 438 miles (705 kilometers) above the planet, surveying the globe every 16 days in image swaths 115 miles (185 kilometers) wide. The two instruments on Landsat 9 will observe Earth in infrared and visible light bands, revealing insights about vegetation and other types of land cover.
Each pixel in the images captured by Landsat 9’s Operational Land Imager 2, or OLI 2, instrument will be about 100 feet (30 meters) across, about the size of a baseball diamond. Landsat 9’s other instrument — the Thermal Infrared Sensor 2, or TIRS 2 — can resolve features about 330 feet (100 meters) in size, roughly the length of a football field.
The Landsat 9 mission is based on the Landsat 8 satellite, which launched in 2013. The Obama administration directed NASA and the USGS to develop Landsat 9 in 2015, using new copies of the OLI and TIRS instruments on Landsat 8.
The Landsat 8 satellite, designed for a five-year lifetime, remains operational. Landsat 8 and 9, working in tandem, will cover all of Earth’s land masses every eight days, according to Jeff Masek, NASA’s project scientist for the Landsat 9 mission.
“This frequency is really critical for assessing change, both for within a single year and between years,” Masek said.
Landsat 9 will also work in concert with other land imaging satellites, such as the European Sentinel 2 missions, to extend the continuous global coverage of land masses since the launch of Landsat 1 in 1972.
“When we further add in the data from the similar Sentinel 2A and 2B (satellites), we can get that refresh down to two to three days,” St. Germain said.
The Landsat data archive catalogs changes in land cover, water quality, glacier flow, and other properties of Earth’s surface, according to NASA. The thermal infrared data from Landsat satellites provide information on irrigation and water usage.
Scientists and forest managers use Landsat data to measure the impact of wildfires and chart the growth of cities.
“I like to think of Landsat as something like a Swiss Army knife,” Masek said. “Out of one basic set of observations or measurements, we feed a whole range of different Earth science applications.
“It’s key role is to track both human-induced and natural changes to the land environment to better support land management decision-making,” Masek said. “And along the way, we’re able to assemble and visualize an amazing history of how the planet has changed over the last half-century.”
The first Landsat satellite launched in 1972. Here’s a list of the Landsat missions to date:
• Landsat 1: Launched July 23, 1972, on a Delta 900 rocket. Operational until January 1978.
• Landsat 2: Launched Jan. 22, 1975, on a Delta 2910 rocket. Operational until February 1982.
• Landsat 3: Launched March 5, 1978, on a Delta 2910 rocket. Operational until March 1983.
• Landsat 4: Launched July 16, 1982, on a Delta 3920 rocket. Operational until 1993.
• Landsat 5: Launched March 1, 1984, on a Delta 3920 rocket. Operational until 2013.
• Landsat 6: Launched Oct. 5, 1993, on a Titan 2 rocket. Did not reach orbit due to apogee propulsion system failure.
• Landsat 7: Launched April 15, 1999, on a Delta 2 rocket. Remains operational.
• Landsat 8: Launched Feb. 11, 2013, on an Atlas 5 rocket. Remains operational.
The new Landsat 9 satellite will replace Landsat 7, which is operating well beyond its design life. Once Landsat 9 is operational, Landsat 7 will be moved into a different orbit, where it will wait for docking of a NASA robotic satellite servicing mission that will attempt to refuel the aging satellite later this decade.
Landsat satellites have detected changes in the health and coverage of forests, and observed the impacts of climate change of ecosystems around the world. Masek said the Landsat satellites have noticed increased plant cover and melting of ice caps at higher latitudes due to warming temperatures.
“We can look at the types of crops being grown, we can measure their health, we can look at agricultural productivity,” Masek said. “We can also use the surface temperature measurements from TIRS, and energy budget models, to measure crop water consumption, which is an important application in the western U.S.”
While Landsat satellites are focused on land imaging, observations can also track changes in lake sizes, water quality, and help with the early detection of algal blooms, according to Masek.
“New applications are emerging all the time, so with the launch of Landsat 9, the user community, the science community, is absolutely looking forward to this launch, and for Landsat 9 to join the Landsat constellation,” Masek said.
NASA says the Landsat archive includes more than 8 million images captured since 1972.
David Applegate, acting director of the USGS, said the Landsat 8 and 9 satellites will combine to downlink nearly 1,500 images per day for distribution to hundreds of thousands of users around the world, free of charge.
“Much like GPS and weather data, Landsat data are used every day to help us better understand our dynamic planet,” Applegate said.
Landsat data are also widely used in the Western United States, where farmers, ranchers and city managers divide up scarce water resources.
“Landsat is our most economically impactful Earth science mission,” St. Germain said.
Like Landsat 8, the new Landsat 9 spacecraft is has a design life of five years, but carries enough fuel to operate for at least a decade.
“If you put the two satellites side by side, they would look very similar,” said Del Jenstrom, Landsat 9 project manager at NASA’s Goddard Space Flight Center. “Like Landsat 8, we have two instruments. We have the Thermal Infrared Sensor 2, which we call TIRS 2, which is a two-band thermal imager, and we have the Operational Land Imager 2, OLI 2, which is a nine-band reflective imager with spectral coverage from visible to shortwave infrared.”
Jenstrom said the new satellites biggest improvement over Landsat 8 was to make changes to the TIRS 2 instrument, built in-house at Goddard. Engineers added more backup components to make the TIRS 2 instrument more reliable, and improved optics inside the sensor to correct an issue with stray light reaching the focal plane.
Teams on the ground compensated for Landsat 8’s stray light issue with changes to the way they process the imagery, but the underlying problem has been fixed for Landsat 9.
The OLI 2 instrument, supplied by Ball Aerospace, has two additional imaging bands to detect cirrus clouds and improve images of coastal waters. Jenstrom said the Landsat 9 satellite will downlink 14-bit data from OLI 2, compared with 12-bit data from OLI on Landsat 8, improving sensitivity by about 25%.
Landsat 9 also flies with a new generation of avionics and software. The satellite is also better shielded against orbital debris impacts and static charge build-up, according to Jenstrom.
Emerging commercial space capabilities, such as privately-funded Earth-imaging spacecraft, aren’t a replacement for the government-owned Landsat satellites, St. Germain said.
New commercial startups provide “additional science” and “additional observations” for Earth scientists, she said.
“They don’t today replicate or replace the kind of data we collect with Landsat, but they generally have complementary strengths and can augment our base of understanding,” St. Germain said.
“As an example, commercial systems, generally they can observe more often, but they generally don’t observe in all the wavelengths we need to do the work we do with Landsat,” she said. “And also those commercial systems often rely on systems like Landsat as an anchor for their calibration and stability.”
NASA and the USGS are in the early stages of planning for the next Landsat mission, tentatively named Landsat Next, that could launch in the late 2020s.
Monday’s launch was the penultimate flight of an Atlas 5 rocket from Vandenberg. One more Atlas 5 mission remains on ULA’s launch schedule at Vandenberg in September 2022. That flight will carry a NOAA weather satellite into orbit.
It was the 88th Atlas 5 flight overall, and 16th Atlas 5 launch from Vandenberg.
There are 28 Atlas 5 launches remaining overall before ULA retires the workhorse in favor of the new Vulcan Centaur rocket, which the company hopes to debut in 2022.
The rest of the Atlas 5 missions will blast off from Cape Canaveral in Florida. ULA’s next launch is an Atlas 5 flight from Florida set for Oct. 16 with NASA’s Lucy robotic asteroid probe.
Email the author.
Follow Stephen Clark on Twitter: @StephenClark1.