Wednesday, June 29, 2016

"The smells of Earth are just so strong*"

Tim Peake, UK astronaut (source)

Tim Peake, the first UK astronaut, returned to Earth from the International Space Station (ISS) a short time after its 100,000th orbit. Peake was in space for six months, during which time he conducted a spacewalk and ran the length of the London marathon on a treadmill. Just after he left, the Landsat 8 sensor caught a glimpse of the ISS as it passed between the sensor and the Earth. (See here if you're interested in spotting the ISS yourself.)

In terms of earth observation, the ISS isn't a popular platform, even though it's in a fairly low orbit and there plenty of images (and beautiful video) taken from the station. The ISS orbit isn't ideal for earth observation, because it passes over the earth at different times of the day in different regions. Most earth observation satellites, at least the ones that detect reflected solar energy, are sun-synchronous, and collect imagery at a standard time during the day for everywhere on earth. That way, when we are comparing regions, or looking for features, we can worry less about variability in the sun angle due to the time of day. The best time of day for a satellite overpass depends on what you're looking for, with geologists and archaeologists preferring the start or end of the day with long shadows to help identify structures, and ecologists often wanting midday measurements when ecosystem productivity is at its peak. But everyone wants consistency in overpass time so we can reliably use the same methods in different places or on different dates.

If you're not constrained by needing images to be nadir-view (i.e., looking straight down at the Earth's surface) and sun-synchronous, there are lots of opportunities to see images collected by astronauts themselves. The beauty of these images has been highlighted by American astronaut Scott Kelly, who presents his photos as art. As someone who sometimes spends lots of time looking through satellite imagery, trying to find patterns among the noise, it's hard for me to step back and just appreciate the images as art or abstraction. I knew what this one was immediately, though, and recognizing what it was felt similar to appreciating art**.

Even without providing lots of useful geospatial imagery of the Earth, the ISS inspires curiosity about it (not just in kids), and shows our planet to us in new ways. There's certainly plenty of extremely important research that happens on there too. The images from the ISS supply us with lots of fodder for the imagination, which gets people thinking about how we can conceive of the planet we live on and the space around it. Without that, it would be almost impossible for me to communicate with people about what I do.

*The title of this post comes from a quote from Tim Peake upon returning to Earth, but the smells of Earth are changing...

**Not that appreciating art is the same thing as the spark of recognition, it may well be more like experiencing something for the first time ever or some eery combination of the two. As a kid who had a poster of "Earthrise" above her bed, I have appreciated both the familiar and unfamiliar aspects of earth observation.

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