NASA and the U.S. Geological Survey (USGS) are only months away from the launch of the long-awaited Landsat 9 mission, following the recent completion of Design Status Review 3. This third and final design review of the combined Landsat 9 Evolved Expendable Launch Vehicle Secondary Payload Adapter (ESPA) Flight System (EFS) allows a critical element of this important Earth resources mission to move forward into the final stages of integration.
Developed by the U.S. Space Force, the EFS will support up to 18 National Security Space and Civil multi-manifest payloads to be deployed separately to Landsat 9. After having already succumbed to delays in response to the worldwide march of the COVID-19 coronavirus pandemic, the mission is set to fly atop a United Launch Alliance (ULA) Atlas V from Space Launch Complex (SLC)-3E at Vandenberg Air Force Base, Calif., in September.
Despite its numerical designation, Landsat 9 is actually the eighth satellite in a lengthy collaborative effort between NASA and the USGS and will provide moderate-resolution observations of Earth’s terrestrial and polar regions at visible and infrared wavelengths.
Like its predecessors, the data from Landsat 9 will support future land planning, disaster response, water-use monitoring and, more generally, the spacecraft will keep watch over our planet’s ever-changeable climate, ecosystems, water cycle and surface and interior. Like Landsat-8—originally known as the Landsat Data Continuity Mission (LDCM) and launched way back in February 2013—this new spacecraft will ride ULA’s Atlas V 401 booster.
Originally conceived in the mid-1960s as the Earth Resources Technology Satellite (ERTS), one of the Landsat program’s primary instruments—its multispectral scanner—was completed and tested a few months after Neil Armstrong and Buzz Aldrin walked on the Moon[BE1] . The first mission in the series roared into near-polar orbit on 23 July 1972, also from Vandenberg, and three years later the program name was changed to “Landsat”. Solar overheating caused it to be shut down in January 1978, but it was merely the start of a remarkable journey.
Landsats 2 and 3 continued to function, well beyond their planned one-year operational life spans, but the arrival of Landsat 4 in mid-1982 brought disappointment: shortly after launch, it lost half of its electrical power, together with its ability to transmit science data. To compensate for this loss, a backup spacecraft, Landsat 5, was boosted into orbit in early 1984. At one stage, plans were advanced to launch a shuttle mission from Vandenberg in March 1987 to retrieve, repair, and refuel Landsat 4, but these were shelved in the wake of the Challenger tragedy.
However, with the arrival of NASA’s Tracking and Data Relay Satellite (TDRS) network, Landsat 4 rallied and even aided Landsat 5 for a time in 1987 when the latter encountered its own problems. Landsat 4 marked the program’s first use of the Thematic Mapper, which gathered seven spectral bands of data and achieved far higher resolution than its predecessors. Not until the end of 1993 was it finally decommissioned.
As for Landsat 5, it was finally deactivated in June 2013 after a remarkably lengthy period of successful functionality, tempered by serious difficulties in its later years with its backup solar array drive, power and attitude control systems and fluctuations in a critical data-transmission amplifier. Landsat 6 failed to reach orbit in late 1993 and Landsat 7 was successfully launched in April 1999. Despite a malfunction in its Enhanced Thematic Mapper, Landsat 7 continues to operate—with hopes that it may be visited and refueled by NASA’s Maxar-built Restore-L vehicle in the next year or two—and in February 2013 the arrival of Landsat-8 provided an important addition to the fleet.
“Landsat has given us a critical perspective on our planet over the long term and will continue to help us understand the big picture of Earth and its changes from space,” said former NASA Administrator Charlie Bolden in remarks to commemorate Landsat’s 40th anniversary in July 2012. “With this view, we are better prepared to take action on the ground and be better stewards of our home.”
It has even produced an island, 12 miles (20 km) off the northeast coast of Labrador, named in its honor. “Landsat Island” was found in 1976, during a Canadian survey which utilized Landsat 1 data to find uncharted landmarks. Lowered by a helicopter harness, Dr. Frank Hall of the Canadian Hydrographic Service narrowly missed being swiped by a polar bear and thus almost became the first person to meet his maker on the island.
Initiation of the Landsat 9 program got underway in early 2015, with an expectation that the mission would utilize similar instrumentation to Landsat 8: an Operational Land Imager (OLI-2), built by Ball Aerospace & Technologies Corp., which is sensitive to the visible, near-infrared and shortwave-infrared portions of the electromagnetic spectrum, and NASA Goddard Space Flight Center’s (GSFC) Thermal Infrared Sensor (TIRS-2) to examine land-surface temperatures across two thermal infrared bands. This dynamic duo can cover wide areas, yet still provide adequate imagery of urban centers, farms and forests.
With launch originally targeted for December 2020, contracts worth $129.9 million to build Landsat 9 were awarded to Northrop Grumman Corp. were awarded in October 2016.
The program passed smoothly through its System Requirements Review (SRR) and Preliminary Design Review (PDR) stages the following year and in October 2017 ULA was contracted to launch Landsat 9 atop its Atlas V 401 from SLC-3E at Vandenberg—the same rocket type, configuration and launch site as was used for Landsat 8.
During 2018, the flight cryocooler for TIRS was delivered ahead of schedule and the Critical Design Review (CDR) was satisfactorily concluded. In January 2020, OLI-2 and TIRS-2 were successfully integrated aboard Landsat 9.
Under the terms of the contract with ULA, launch was scheduled for June 2021, whilst protecting the possibility of flying the mission as soon as December 2020. However, the worldwide march of COVID-19 pushed both dates inexorably to the right; firstly to no sooner than June 2021 and now September.