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Landsat celebrates 40 years of photographing our planet

Forty years ago today, the first in a string of Landsat satellites was launched to keep continuous track of our planet — and on the 40th birthday, Landsat's handlers demonstrated that satellite observations are the gifts that keep on giving. But for how much longer?

"Landsat has really become the gold standard of remote sensing from space," Anne Castle, the Interior Department's assistant secretary for water and science, said during a birthday celebration at the Newseum in Washington. "It's provided an invaluable, indelible record of the recent history of our planet."

From the beginning, Landsat was designed as a system that would provide freely available data about Earth's condition — documenting agricultural shifts, urban development, deforestation, floods and the impact of climate change and natural disasters. On the flip side, Landsat has chronicled the planet's ability to bounce back from disaster.

The Mount St. Helens eruption of 1980 serves as a perfect example: The time-lapse video below shows how the blast created a dead zone around the volcano in Washington state, and how Mother Nature slowly crept in to reclaim the gray terrain. You'll also see how Landsat tracked the rise of Beijing, the shrinkage of the Aral Sea and other "top 10" changes in our planet's landscape.

Castle said Landsat has provided a "thoroughly objective, continuous look at ourselves in the mirror since 1972," when the first Landsat satellite was launched into polar orbit from Vandenberg Air Force Base on July 23. In a NASA news release, she went even further, calling Landsat's data archive "the world's free press, allowing any person, anywhere, to access vital information without charge."

Landsat's past and future

This "free press" is paid for by the federal government, at an estimated cost of 80 cents per person per year. The seven-satellite Landsat project is the result of a long-term collaboration between NASA and the Interior Department's U.S. Geological Survey as well as the Commerce Department's National Oceanic and Atmospheric Administration.

"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," NASA Administrator Charles Bolden said in the news release. "With this view we are better prepared to take action on the ground and be better stewards of our home."

The eighth satellite in the series, now known as the Landsat Data Continuity Mission, is due for launch from Vandenberg in February 2013. Once it's in orbit, LDCM is to be renamed Landsat 8, joining the 28-year-old Landsat 5 and the 13-year-old Landsat 7 spacecraft on the job.

And then what? That's the problem. The most important benefit of the Landsat program is the continuous, long-term monitoring of the planet's ups and downs — and some observers worry that not enough money or attention has been devoted to what comes after Landsat 8. If, heaven forbid, one or both of the other satellites should go on the blink before LDCM is launched, a 40-year-plus chain would be broken. And Landsat 5 is already faltering.

In May, the National Research Council issued a report saying that U.S. earth observation systems were in an increasingly precarious position due to budget shortfalls, launch failures and shifts in mission plans. "The projected loss of observing capability will have profound consequences on science and society," University of Washington atmospheric scientist Dennis Hartmann, the chair of the committee that wrote the report, warned at the time.

Even during today's Newseum celebration, concerns about the future cast a bit of a pall over the party. Tom Loveland, a USGS senior scientist at the Earth Resources Observation and Science Center in Sioux Falls, S.D., acknowledged during the press briefing that LDCM was currently cast as the last of the Landsat line.

"We still are on a tenuous path, in which we don't know when the next mission takes place," Loveland said.

New ways to use the data

Amid Landsat's midlife crisis, scientists keep finding new ways to use the database that's been built so far. Waleed Abdalati, chief scientist at NASA Headquarters, touted the NASA Earth Exchange, or NEX, which can help scientists easily put together mosaics of satellite imagery "like a giant jigsaw puzzle."

Google is in on the celebration as well: On its Lat Long Blog, the company highlighted its work with USGS and Carnegie Mellon University to create a monster series of interactive time-lapse videos. "With them you can travel through time, from 1999 to 2011, to see the transformation of our planet ... whether it’s deforestation in the Amazon, urban growth in Las Vegas or the difference in snow coverage between the seasons," Google's Eric Nguyen and CMU visiting scholar Randy Sargent wrote.

The Google Earth Engine is among the new tools being developed for mining the quadrillions of bytes of data in the Landsat archive.

Will Landsat still be going 40 years from now? Maybe there'll be a whole new approach to Earth observation that will make the current system and data set look laughably obsolete. But for at least the next couple of decades, if we're going to chronicle the effects of climate change on Earth's surface in a methodical manner, we're going to need Landsat.

"I don't think it's an overstatement to say the success of humanity hangs in the balance," NASA's Abdalati said. Do you agree? Feel free to weigh in with your views, or birthday wishes, in the comment space below.

More from Landsat:

Alan Boyle is's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the dwarf planet and the search for new worlds.