If the weather holds, NASA will launch its newest Earth-observing satellite from Vandenberg Air Force Base in southern California late Monday morning.
An Atlas V rocket is scheduled to carry Landsat 8 into space just after 2 p.m. Eastern time. Once in orbit, the $855 million probe will begin capturing detailed images of Earth’s surface, adding to an unbroken record that began with Landsat 1 in 1972.
“Since the launch of Landsat 1, we have seen and we have caused dramatic changes to the global land surface that continue today at rates unprecedented in human history,” Jim Irons, a project scientist at NASA’s Goddard Space Flight Center, told reporters in January. “These changes are due to increasing population, advancing technologies and climate change.”
Scientists have used Landsat data to follow the growth of cities, monitor the use of groundwater, track shrinking glaciers and map coral reefs. Satellite images have revealed the march of bark beetles through western U.S. forests and captured the destruction wrought by natural disasters.
But as reliance on Landsat imagery has grown, the program’s aging satellites have stumbled. A successful Landsat 8 launch would be a relief to researchers who have watched and worried as NASA has scrambled to keep its current pair of orbiters in working order.
The problems began with Landsat 6, which failed at its 1993 launch. Landsat 5, which was decommissioned last month after 28 years of service, has also run into problems.
That satellite lost the ability to collect images in 2005, when its batteries failed to charge, and again in 2009. Later that year, Landsat 5’s transmitter stopped sending information back to NASA. The problem flared again in 2011.
And about a decade ago, Landsat 7, which was launched in 1999, developed sensor problems that blank out about a fifth of each image it collects.
“Landsat 8 couldn’t come at a better time, because of the way things are changing right now,” said Ted Scambos, a senior scientist at the National Snow and Ice Data Center and a member of NASA’s Landsat 8 science team.
For scientists who study ice, like Scambos, Landsat has been “a phenomenal tool,” he said. “Being able to see how glaciers used to flow, used to appear, used to extend, and then to come back and see rapid changes, especially in the last decade, is invaluable.”
Scott Loarie, an ecologist at the Carnegie Institution for Science, said the Landsat probes have “been the bread-and-butter” of the country’s array of Earth-observing satellites.
Landsat imagery is coarse enough to allow the satellite to scan the entire Earth’s surface every 16 days, but detailed enough to be used in mapping applications like Google Earth.
“It’s a really nice balance,” Loarie said.
The new satellite, which will carry two instruments, will collect images of Earth’s surface at a higher resolution than any its predecessors — including Landsat 7, which will remain in use — and more of them.
Landsat 8 was designed to capture up to 400 pictures per day, NASA officials said, adding to the existing archive of roughly 3.5 million Landsat images freely available online.
But even as scientists cheer the new satellite’s impending launch, questions remain about what will replace it.
According to NASA, which designs and launches Landsat probes, and the U.S. Geological Survey, which handles the data they produce, there is no plan yet for a “Landsat 9.”
“Right now, NASA and the USGS are in discussion with the administration and our other stakeholders trying to determine what path we’re going to take forward,” said David Jarrett, the NASA program executive in charge of Landsat 8.