This still image from International Space Station crew member, Don Pettit, shows the edge of the Earth during a solar eclipse on May 21, 2012, as seen from the station. (NASA)
View large image
It boggles the mind to consider how different the wonders of the universe look when viewed from outside our usual perspective. We are used to seeing everything with our heads tilted back, looking up, and through the distinct filter of the Earth's atmosphere. From aboard the International Space Station, however, the point of view is uniquely altered. The crew can be eye-level or even above amazing sights!
While the images and videos astronauts capture from station are impressive for their beauty, there is real science behind the data astronauts collect and share through photography. Their imaging efforts can also be part of the Crew Earth Observations, or CEO, investigation on the station. This study provides researchers with station-level views of the planet to improve knowledge of surface changes over time, along with dynamic events such as storms, floods, fires and volcanic eruptions.
NASA astronaut Don Pettit recently captured two phenomena from aboard station: the Lyrid meteor shower on April 22, and a solar eclipse on May 21. Pettit also is primed to record images of the upcoming transit of Venus across the Sun on June 5 -- something that happens only twice a century.
For the Lyrid meteor shower, which peaked April 21, Pettit focused his camera equipment on the Earth below while watching the celestial event. The resulting video, which shows the meteors ablating or burning up in the atmosphere, is a composite of 316 still images he took while from his orbital vantage point.
During the rare solar eclipse, a month later, the moon cast its shadow across the Earth as it moved between the planet and the Sun. Pettit shared his experience of capturing the solar eclipse in a recent "Solar Eclipse from Space" blog entry. "It is amazing to see an eclipse from orbit," Pettit said. "The shadow on Earth looks just like what you see in the physics books and the astronomy book where those folks figured all that out without ever having seen what that shadow looks like."
According to William Stefanov, Ph.D., a terrestrial remote sensing scientist and a crew trainer in Earth science, the crew keeps eyes alert for other types of phenomena. These include aurora displays in both the Northern (aurora borealis) and Southern (aurora australis) Hemispheres, and polar mesospheric clouds, also known as noctilucent clouds. The auroras are caused by interactions between the solar wind and the Earth's magnetic field, while the processes behind polar mesospheric clouds are not as well understood.
Astronomical events like the upcoming transit of Venus, or the partial eclipse of the paired stars known as Epsilon Aurigae, which took place during 2009-2011, also are of interest, due to the unique orbital perspective of the station. The transit of Venus, where the planet will cross the face of the Sun producing a silhouette, is particularly exciting, as it will not happen again until December 2117.
This image shows the peak of the Lyrid meteor shower, as photographed by crew member Don Pettit from aboard the International Space Station on April 22, 2012. (NASA)
View large image
Sometimes researchers make specific imaging requests to the astronauts aboard station, but there is no guarantee they will be able to photograph the objects. Some complications include crew availability to take imagery, as they have full schedules performing other experiments and maintaining the operation of the space station. There also are the orbital position of the station and the location of its windows, which may not present the right opportunity for observing a desired phenomena at a specific time. For land surface target requests, there is the additional concern of whether cloud cover may obscure the view of a particular area of interest on the ground.
These challenges, however, can lead to innovation in imaging techniques and even be fun for the crew to tackle. Stefanov notes that necessity is frequently the mother of invention aboard the space station. "Whether it's mounting two cameras together to obtain simultaneous, coregistered images or improvising a camera motion tracking system from parts on hand, the crew has demonstrated the ability to find solutions to unforeseen technical imagery challenges," Stefanov said.
There also is evidence that pursuing images of Earth and the activity of photography on orbit may support the health of the crew, as discussed by NASA's International Space Station Program Scientist Julie Robinson, Ph.D., in a post on her blog, A Lab Aloft. Regardless of whether the images are part of time-off opportunities or assigned objectives, the end results are a sight to behold for all who see them.