A NASA astronaut has shared a rare photo snapped from space that “cannot be taken anymore”.
Astronaut Donald Pettit shared an image he had taken from the International Space Station, explaining why it’s no longer possible to get a similar shot.
Taking to Instagram to share the photo he’d captured of stars from aboard the ISS.
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In the caption, Pettit revealed that things had changed on the station, meaning photos like that one were no longer possible.
Pettit said: “Star field image of the Southern Cross from @iss during Expedition 6 in 2003 showing the atmosphere on edge illuminated by green airglow from atomic oxygen.
“At this time Space Station’s orbital attitude was a solar inertial attitude (XPOP) that allowed the solar panels to point towards the sun without any tracking (solar tracking was not added to ISS until much later).
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“Essentially, the station itself was the tracking mechanism thus for a camera mounted to Space Station, a time exposure yielded stars as pinpoints.
“Since about 2006, ISS has flown an Earth pointing attitude where one side remains pointed nadir towards Earth (LVLH) and time exposures yield stars that are arcing trails. This attitude limits sharp star images to less than a half second.
“For my upcoming flight, I am bringing a wind up tracking device that will compensate for the current space station motions and once again allow long time exposures with pin point stars.
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“With our current generation of digital cameras, I hope to continue these astrophotography star field images.”
In other words, the ISS adjusted its angle, meaning that one side would be pointing at Earth.
Using a 30-second exposure to snap stars, now taking the same pic would cause the stars to appear as arcing trails.
Posting another image which shows these trails, Pettit wrote: “One of my star trails from @iss, blurring golden city lights with the arcing stars of deep space.
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“Composites like this are made from many images, creating a time history of earthly and cosmic phenomena that maps our universe as a function of time. The blue marks of lighting strikes personify this, reflecting storm intensity. Science revealed through art.”
Now, the astronaut has plans to take a tracking device to compensate for the motion of the ISS in an upcoming trip.
This will hopefully mean that once again, he’ll be able to capture more star field images from above our atmosphere.