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But when it comes to imagery, phones and computers perform similar functions: snap, store, share and sort.

Of course, with EROS, the “snap” takes place high above Earth, with images beamed down from a series of Landsat satellites for 51 years. EROS stores over 74 petabytes of remote sensing data (over 1 million phones’ worth) and shares it via the internet and, since 2021, the cloud, with an explosion in downloads. 

EROS scientists sort and analyze that data in programs that benefit everyone, from agriculture to fire management to conservation. That’s all made possible by cloud computing and a series of high-performance computers (HPCs) housed in EROS’ Computer Room 2. The latest HPC is Hovenweep, installed in June 2023. Hovenweep is expected to perform 660 teraflops when fully operational (a teraflop is 1 trillion floating operations per second!).

The path from 60 kilobytes to 660 teraflops at EROS in many ways matches the overall trajectory of exponential computer growth that seems commonplace today. However, EROS had to create and innovate to keep up with the demand for imagery and science as the field of satellite remote sensing of Earth grew from its start in the early 1970s.

The IBM 360-30

The IBM 360-30 that started off the computer division was a hand-me-down of sorts—EROS just had to pay the cost of transportation from the USGS Astrogeological Office in Flagstaff, Arizona. The computer was the first equipment to make its home in EROS’ temporary Downtown Office, the former Soo Hudson Building at 10^th Street and Dakota Avenue in Sioux Falls, South Dakota, in late 1971.

The 360-30’s first job seems simple today: Keeping track of the imagery that would pour into EROS once ERTS-1 (Landsat 1) launched in 1972, along with the aerial photography that was already flowing in from other government agencies. But there was no template for the task.

“We’d talk about doing things like databases and image files and stuff like that—we didn’t even know what the terms meant,” said R.J. Thompson, at the time one of the members of the original Computer Services Branch. “But we were learning. We were learning quick.” Employees puzzled out the details on coding sheets or the backs of envelopes, then entered them into the computer via keypunched program cards.

Eventually, staff members routinely would enter information about each Landsat scene into a Main Image File. When someone ordered an image, the computer could generate a list of potential matches printed on tractor-drive-style paper for the customer to choose from.

As helpful as the computer database was, the process was still time- and labor-intensive, requiring mail back and forth as well as typing out replies on IBM Magnetic Card typewriters that weren’t even connected to the IBM 360-30. So the computer staff innovated and wrote their own software to link the machines, improving the response time.

The Burroughs 6700

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When the Burroughs 6700 came in 1976, it took up two-thirds of the only computer room then at EROS. The mainframe was one of the largest computers in the Midwest at the time.

The Burroughs’ chief value, though, was as a gateway to digitally processing film. The EROS photo lab’s expertise at developing film was second to none. But its ability to tailor images for customers was limited by the fact that EROS received already-processed film from Goddard Space Flight Center in Maryland.

With the added horsepower of the Burroughs, the computer branch was able to customize software to digitally process film, helped by photo lab personnel. The result was called EDIES—the EROS Digital Image Enhancement System.

In fact, software was continually being developed in-house during this era:

• In April 1976, EROS installed the IDIMS (Interactive Digital Image Manipulation System) software system, which was used for a decade and allowed scientists to write programs to analyze satellite data.
• The INORAC (Inquiry, Order, and Accounting) system was implemented in February 1977. It tracked repeat customers, standing accounts, orders and payments and created orders for the photo lab and computer branch as well as shipping labels.
• In January 1979 came software that allowed EROS computers to interface with NASA computers and receive satellite data in an electronic form that could be converted to images—the EROS Digital Image Processing System, or EDIPS.

More Innovations

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One of EROS’ key missions was to spread knowledge about how to use Landsat data to other government agencies and to universities. Classes at EROS were well-attended, and there were opportunities to teach outside of EROS as well.

So in 1980, the computer branch developed the Remote Image Processing System (RIPS), a portable computer for digital image processing. It wasn’t as easy to carry as today’s laptops, and there wasn’t a battery pack. But RIPS interfaced with many different host computers, becoming part of EROS workshops.

While the Burroughs was still the main computer, EROS helped set the worldwide standard for computer-compatible tapes in 1981, and in 1982, Landsat data became available on floppy disk.

EROS was also interested in using geographic information systems (GIS) to merge different kinds of data bases, starting in 1984. EROS demonstrated the capability with an Oregon-based pilot project called the Federal Mineral Land Information System (FMLIS), which layered maps of mineral resources, federal mineral rights and regular maps of roads in order to identify where mineral deposits were located.

Software Squabble

In 1985, when the Burroughs was replaced by a new VAX computer system, the computer branch pushed to replace the homegrown IDIMS image software with the Land Analysis System (LAS), a joint project with Goddard Space Flight Center. The LAS was more flexible, able to be installed on other computers.

This annoyed the applications branch. Scientists were fluent in using IDIMS and resisted the shift. Adding insult to injury, the computer branch also switched the EROS operating system to UNIX, which at the time was not well known or thoroughly tested.

Over time, the move to UNIX proved its worth, and the enmity between the two branches eventually died down. Elsewhere at EROS, offices changed along with the rest of the world. Administrative assistants received IBM Model-286 personal computers (PCs) in 1988 along with training in MS-DOS.

Getting Online

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In June 1991, for the first time ever, any customer with a PC could browse data, order products and even directly download some products remotely through EROS-developed software called the Global Land Information System (GLIS), the predecessor of programs still in use today to download Landsat data.

And that data was steadily amassing, creating the need for more digital storage space. In 1992, EROS acquired its first mass storage robotics system, called a silo, for Computer Room 1. The 4400 Automated Cartridge System used tape cartridges and had a capacity of 1 terabyte.

Step by step, EROS’ online footprint expanded in 1993. EROS began using the World Wide Web and other information service protocols and explored using the Mosaic browser on a small scale inside the facility, eventually broadening its use externally. Later that year, the first EROS website appeared online, and employees began to use email. Windows 3.1 was installed on PCs throughout the center.

In 1994, EROS debuted internet access to its products, allowing customers to directly download data to their computers. By September 30, more than 70,000 data files were being downloaded each month.

Exponential Growth

As the amount of data exploded at EROS, a race between growth in data and additional computing power took off. In 1995, the CM-5 supercomputer was installed at the center. By 1998, 25 years into EROS’ existence, 1 terabyte of data was stored in its archive.

But storage had the edge for the moment—the center’s equipment was now able to house 1.5 petabytes of data in anticipation of the 1999 launch of Landsat 7, which would dramatically increase the total data intake. To keep up with the workload after the satellite was operational, an automated server backup system was added in October 2000. This eliminated the need for computer operations staff to perform manual backups, which had become more cumbersome and inefficient as more servers were added. 

In 2008, as data from both Landsat 5 and Landsat 7 continued to accumulate, downloads of Landsat data also increased as the archive was opened to the public at no cost. This was a major undertaking because it required switching from delivering data to users on DVDs, , to providing all the data online via EarthExplorer and GloVis.

By 2012, the center expanded storage again, this time in advance of Landsat 8’s 2013 launch. The 2012 Data Archive System was a StorageTek SL8500 Tape Library with a 50 petabyte capacity.

But something bigger was on its way.

The Era of High-Performance Computing Systems

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With Landsat data as just one source of continually expanding data, the USGS Core Science Systems Mission Area decided to lean forward in its planning for high-performance computers (HPCs) by setting up the Advanced Research Computing (ARC) group. It wasn’t just about storage, of course. Research involving ever-larger data sets also required more computing power.

Rather than reacting to the data squeeze, ARC studied trends to get ahead of the curve. In 2014, the USGS facility in Denver installed the Yeti HPC system, with a performance of 110 teraflops, for use by all USGS researchers, including those at EROS.

It was a welcome advance, but there was a “bandwidth” problem in South Dakota for the biggest projects requiring the most data. Even with ever-improving web connections, the distance between Denver and Sioux Falls sometimes caused a slowdown in data analysis.

However, always looking ahead, ARC had plans for South Dakota, too. In 2019, the Denali and Tallgrass HPC systems arrived at EROS, with Tallgrass described as more of a prototype and Denali clocking in at 440 teraflops. The duo enabled USGS scientists to do their training runs and to explore and develop artificial intelligence and machine learning.

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Leapfrogging Computers

The advent of HPC systems at EROS coincided with the decision to allow users to access Landsat data from the cloud through a contract with Amazon Web Services. The volume of downloads skyrocketed six-fold in 2021 after the advent of the cloud and continues to see record growth, showing continued demand for Landsat data.

But cloud usage doesn’t conflict with the continued addition of new computing power, said Jeff Falgout, the technology lead for ARC. “The cloud is just another tool in the toolbox,” he said, one that ARC carefully looks into as it considers costs for leasing new HPC systems.

Leasing rather than purchasing is yet another facet of ARC’s forward-thinking outlook on computers. Even HPC systems lose their cutting-edge status at facilities like EROS. So whenever a new one is installed, the older one is decommissioned and retired.

That will be the fate of Yeti now that Hovenweep has come to Sioux Falls. “We plan on a five-year lifespan for each machine. And we’re trying to leapfrog each one,” Falgout said.

For now, Hovenweep rests supreme in Computer Room 2 alongside Tallgrass and Denali, secure in its position as (by Falgout’s estimate) the most powerful computer in the Department of the Interior as well as one of the biggest in storage capacity. But Falgout is already working on its replacement, a process that takes several years of careful planning.

Into the Cloud

As EROS and USGS lean into the future with computing, the cloud will play a major role for scientists both inside and outside of the center. The cloud doesn’t just store data—the data can be processed within the cloud.

For example, when EROS upgraded the entire Landsat archive in 2020, creating Collection 2, it took only five weeks to process at a clip of 450,000 scenes per day. By comparison, Collection 1 took 18 months to process in 2017. Researchers at various projects that release large amounts of data, whether housed at EROS or not, also can leverage the speed of the cloud, getting information out that much faster to policy makers and the general public.  

Between the cloud and HPCs, it might seem as though we’re light-years away from the used 60-kilobyte IBM 360-30 at EROS’ beginning. But there’s a clear continuity between the computing innovators at EROS over more than five decades: a drive to adapt and customize existing technology to fit the data and research needs at the center while meeting the needs of customers around the world.