corona satellite

2 Articles

Solar Dynamics Observatory: Our Solar Early Warning System

July 9, 2024 by 3 Comments

Ever since the beginning of the Space Age, the inner planets and the Earth-Moon system have received the lion’s share of attention. That makes sense; it’s a whole lot easier to get to the Moon, or even to Mars, than it is to get to Saturn or Neptune. And so our probes have mostly plied the relatively cozy confines inside the asteroid belt, visiting every world within them and sometimes landing on the surface and making a few holes or even leaving some footprints.

But there’s still one place within this warm and familiar neighborhood that remains mysterious and relatively unvisited: the Sun. That seems strange, since our star is the source of all energy for our world and the system in general, and its constant emissions across the electromagnetic spectrum and its occasional physical outbursts are literally a matter of life and death for us. When the Sun sneezes, we can get sick, and it has the potential to be far worse than just a cold.

While we’ve had a succession of satellites over the last decades that have specialized in watching the Sun, it’s not the easiest celestial body to observe. Most spacecraft go to great lengths to avoid the Sun’s abuse, and building anything to withstand the lashing our star can dish out is a tough task. But there’s one satellite that takes everything that the Sun dishes out and turns it into a near-constant stream of high-quality data, and it’s been doing it for almost 15 years now. The Solar Dynamics Observatory, or SDO, has also provided stunning images of the Sun, like this CGI-like sequence of a failed solar eruption. Images like that have captured imaginations during this surprisingly active solar cycle, and emphasized the importance of SDO in our solar early warning system.

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The CIA’s Corona Project Was About Satellites, Not A Virus

August 23, 2020 by 14 Comments

We take orbital imagery for granted these days, but there was a time that it was high technology and highly secretive. [Scott Manley] has a good overview of the CIA’s Corona spy satellites, along with declassified images from the early days of the program.

It seems strange today, but the spy images needed high resolution and the only practical technology at the time was film. The satellite held a whopping 3,000 feet of film and, once shot, a capsule or bucket would return to Earth for retrieval and development. They didn’t make it to land — or at least they weren’t supposed to. The CIA didn’t want opponents sweeping up the film so an airplane was supposed to snag the bucket as it descended on a parachute, a topic covered in [Tom Nardi’s] article about the history of catching stuff as it falls from space.

The early cameras could see detail down to about 40 feet. By the end of the program in the 1970s, improved cameras could see down to 3 feet or less. Later satellites had a 3D-capable camera and multiple return buckets. The satellites were — officially — a program to expose biological samples to the space environment and return them for analysis. The Discover program was pure cover and the whole thing was declassified in 1992.

Of course, film from airplanes also had a role. Some spy satellites tried to scan film and send the data back, but that saw more use on lunar missions where returning a capsule to Earth was a lot more difficult.

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