GeoLog

International Space Station

Imaggeo on Mondays: Watching the world from space with EarthKAM

Imaggeo on Mondays: Watching the world from space with EarthKAM

This photo was taken from the International Space Station (ISS), approx. 400 km above the Earth, in the NASA-led educational project Sally Ride EarthKAM (www.earthkam.org), Mission 58, April 2017. The image was requested by a team of 10th and 11th grade students from the National College of Computer Science, Piatra-Neamț, Romania, coordinated by me. The lenses used on the digital camera mounted on the ISS are 50 mm focal length. The area photographed is a region of 185.87 km wide and approx. 123.5 km long, from Utah, USA. The view is spectacular, a perfect equilibrium between mountains, canyons, lakes and bays.

It’s just one of the pictures that my students had the opportunity to get from the ISS. Even though we weren’t there on the ISS to trigger the camera, all the locations in which the photographs were taken were chosen by us, on the track of the ISS.

The project activities were very complex. The students learned about the Earth, its rotation and gravity, and about the space station and its orbit. They completed their knowledge of physics, understanding how from the ISS orbit we can have another perspective of the Earth. They chose the places on the Earth to be photographed, studied these regions and monitored the weather conditions for better photo opportunities. They identified the places on Google Earth, analysed the photos and then created QR codes for some of them.

Below are the QR codes for the photo “Awesome trip above the Earth”:

 

The ISS became an innovative learning environment for the students. The astronauts’ availability for engaging in educational programmes, sharing their extraordinary experiences of becoming aware of the beauty and fragility of the Earth from the ISS orbit, has increased the attractiveness of learning about space. As Sally Ride, the first American astronaut woman on the ISS, said:

“When I was orbiting Earth in the space shuttle, I could float over to a window and gaze down at the delicate white clouds, brilliant orange deserts, and sparkling blue water of the planet below. I could see the coral reefs in the oceans, fertile farmlands in the valleys, and twinkling city lights beneath the clouds. Even from space, it is obvious that Earth is a living planet.”

The photo was integrated into a photo exhibition called “The Earth’s Colors” that I realised with my students at my college, which led the viewer on a global trip, discovering how beautiful and fascinating the Earth viewed from Space is. Satellite photography offered my students a new world perspective, encouraging them to ask questions and to search for the answers. It was a new and exciting way to travel and discover our planet.

The project was a great opportunity, not only for my students but also for thousands of other students around the globe, to study the Earth in a way that complements different subjects in order to better understand our world. It also has strengthened my conviction that, as the teacher and Challenger astronaut Christa McAuliffe said:

“…space is for everybody. It’s not just for a few people in science or math, or for a select group of astronauts. That’s our new frontier out there, and it’s everybody’s business to know about space.”

By Diana Cristina Bejan, physics teacher, The National College of Computer Science, Piatra-Neamț, Romania

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/.

Geosciences column: Making aurora photos taken by ISS astronauts useful for research

Geosciences column: Making aurora photos taken by ISS astronauts useful for research

It’s a clear night, much like any other, except that billions of kilometers away the Sun has gone into overdrive and (hours earlier) hurled a mass of charged particles, including protons, electrons and atoms towards the Earth.  As the electrons slam into the upper reaches of the atmosphere, the night sky explodes into a spectacular display of dancing lights: aurora.

Aurora remain shrouded in mystery, even to the scientists who’ve dedicate their lives to studying them. Photographs provide an invaluable source of data which can help understand the science behind them. But, for aurora images to be of scientific value researchers need to know when they were taken and, more importantly, where.

You’ve got to be in the right place at the right time to catch a glimpse of the elusive phenomenon. In the Northern Hemisphere, aurora season peaks in autumn through to winter. Geographically, the best chance of seeing them is at latitudes between 65 and 72 degrees – think the Nordic countries.

That is unless you are an astronaut on the International Space Station (ISS), in which case, you’ve got the best seat in the house!

The orbit of the ISS means it skims past the point at which aurora intensity is at its peak, which also happens to be the point at which they look their most spectacular. Its orbital speed means it can get an almost global-scale snapshot of an aurora, passing over the dancing lights in just under 5 minutes.

Not as much is known about Aurora Australis (those which occur in the southern hemisphere) as we do about the Northern Lights (visible in the northern hemisphere), because there are far less ground-based auroral imagers south of the equator. The ISS orbit means that astronauts photograph Aurora Australis almost as frequently as Aurora Borealis, helping to fill the gap.

Testament to the privileged viewpoint is the hoard of photographs ISS astronauts have amassed over time – perfect for scientists who study aurora to use in their research.

Time-lapse shot from the International Space Station, showing both the Aurora Borealis and Aurora Australis phenomena. Credit: NASA

Except that, until recently, the ISS photographs were of little scientific value because they aren’t georeferenced. The images are captured by astronauts in their spare time using commercial digital single lenses reflector cameras (DSLRs), which can’t pinpoint the location at which the photographs were taken – they were never intended to be used in research.

Now, researchers at the European Space Agency (ESA) have developed a method which overcomes the problem. By mapping the stars captured in each of the photographs and the timestamp on the image (as determined by the camera used to take the photograph), the team are now able to geolocated the images, giving them accurate orientation, scale and timestamp information.

Despite the success, it’s not a straightforward thing to do. One of the main problems is that the timestamps aren’t always accurate. Internal clocks in DSLRs have a tendency to drift. Over the period of a week they can be out by as much as a minute, making it difficult to establish the location of the ISS when the image was captured. This has implications when creating the star map, as the location of the station is used as a starting point.

To resolve the issue, aurora images which also include city lights can be aligned to geographical maps using reference city markers to get a timestamps accurate to within one second or less. In the absence of city lights, images which also capture the Earth’s horizon are aligned with its expected position instead. The correction works best if both city lights and the horizon can be used.

Errors are also introduced when the star maps can’t be fully resolved (due to the original image being noisy, for example) and because the method assumes that auroras originate from a single height, which isn’t true either.

detailed comparison between the ISS image plotted in Fig. 11 (b) and the contemporaneous image acquired by the SNKQ THEMIS ASI (a) . The original ISS image is plotted in (c) . Red and blue symbols trace the locations of the j shaped arc and northern edge of the main auroral arc, respectively, derived from their locations in the THEMIS image. The features are marked with the same coloured arrows in (c) . The magenta arrows point out a vertical feature projected very differently in (a) and (b) .

A detailed comparison between an ISS image of aurora (a) plotted and (b) the contemporaneous image acquired by the SNK THEMIS ASI [ground-based]. The original ISS image (a) is plotted in (c). For more detail see Riechert, et al., 2016.

Comparing images of an aurora on 4 February 2012, captured both by the ISS crew and a ground-based instrument, has allowed the researchers to test the accuracy of their method. Overall, the results show good agreement, but highlight that the projection of the ISS images has to be taken into account when interpreting the results.

Now, a trove of thousands of Aurora Borealis and Australis photographs can be used by researchers to decipher the secrets of one the planet Earth’s most awe-inspiring phenomenon.

By Laura Roberts Artal, EGU Communications Officer

 

References:

Riechert, M., Walsh, A. P., Gerst, A., and Taylor, M. G. G. T.: Automatic georeferencing of astronaut auroral photography, Geosci. Instrum. Method. Data Syst., 5, 289-304, doi:10.5194/gi-5-289-2016, 2016.

Automatic georeferencing of astronaut auroral photography: http://www.cosmos.esa.int/web/arrrgh

The research was accomplished using only free and open-source software. All the images processed to date are made freely available at htttp://cosmos.esa.int/arrgh, as is the software needed to produce them.