Less than two hours remain until the launch of Landsat 8, the latest leg of a satellite mission that’s creating the “longest continuous record of changes in Earth’s surface as seen from space.” The mission has been tracking the Earth’s changing face since 1972 and has unveiled everything from the near-disappearance of the Aral Sea to the devastation of Mount St Helens and the development of Alberta, Canada’s expansive tar sands projects.
The size of a large jeep, the US$855-million spacecraft will circle Earth at an altitude of about 700 kilometres, carrying sensors of even higher precision than its predecessors. Instead of scanning the terrain below it with a mirror and sending the signal to a few sensors, it will capture instantaneous views of a 185-kilometre swathe of Earth, using some 7,000 sensors for each bandwidth
The new satellite will take the place of the failed Landsat 5 satellite (which broke down in December, after circling the Earth for a 29 years) and of the Landsat 7 satellite (which has been flying for 14 years and now bears some failed equipment). Landsat 5′s nearly three decades of service are extraordinary; the satellite was designed to fly for just three years.
Since Landsat’s mission is to track changes in the Earth’s surface, from water and forest cover to the sprawl of cities, having a gap in the record would be devastating. Back in 1993, the Landsat 6 satellite failed to reach orbit. Though a failed launch for Landsat 8 is unlikely, Wired‘s Betsy Mason points out that it would lead to an gap in the record, as “Landsat 7 would run out of fuel near the end of 2016, before a replacement could be built and put into orbit.”
Aside from its scientific usefulness, Landsat has also been a favorite for those looking at the Earth as art. Indeed, the United States Postal Service recently released a stamp series based on some of the Landsat satellite’s stunning images. Landsat 8 is scheduled to launch from Vandenberg Air Force Base in California at 10 am PST, 1 pm EST. You can follow allow with the Landsat mission on twitter, or watch the launch live.
More from Smithsonian.com:
Scenes From a Changing Planet
Share a Bit of Earth’s Majesty With Every Letter You Send