The upcoming total solar eclipse across the United States on August 21 may very well become the single most photographed event in human history, as million of people will journey into a narrow 60-70 miles wide path of totality stretching from Oregon to South Carolina.
Plenty of aircraft can be expected to intercept it as well, from the military to NASA, NOAA, private pilots and more.
But the astronauts onboard the International Space Station (ISS) will arguably have the ultimate view, as they orbit 250 miles overhead at 17,500 mph, with opportunities to observe and photograph both a partial eclipse (when far from the path of totality) and the shadow of the moon moving across the Earth’s surface (when close-by).
In the charts below, segments of the ISS orbit track in sunlight are colored yellow, while segments in darkness are colored black.
During the first pass through the Moon’s penumbra, ISS will experience a partial solar eclipse with 37% of the Sun covered up at maximum. ISS will not see the Moon’s umbra on the Earth’s surface. ISS passes over the western United States and southeastern Canada during this pass. See figure to the right representing ISS’s location at maximum eclipse. At the time of the figure (16:41:02 UT), the total portion of the eclipse has not yet started for the Earth. A partial eclipse is already in progress and is witnessed by ISS.
During the second pass through the Moon’s shadow, ISS will experience a partial solar eclipse with 44% of the Sun covered up at maximum. ISS will witness the Moon’s umbra moving from southwestern Kentucky to northern Tennessee during a portion of this pass. The Moon’s umbra is visible on the Earth from ISS’s viewpoint while ISS traverses from southern Canada just north of the Montana/Canada border to the Gulf of Saint Lawrence. At the closest approach at 18:24 UT, ISS will be just south of the Hudson Bay while the Moon’s umbra shadow is located in southwestern Kentucky just over 1700 km away. While ISS does not pass near the location of the Moon’s umbra, the Moon’s umbra should still be easily visible near the horizon.
During the third pass through the Moon’s penumbra, ISS will experience a partial solar eclipse with 85% of the Sun covered up at the maximum point at 20:18 UT a few minutes prior to orbital sunset. ISS will not see the Moon’s umbra on the Earth surface since the umbra will have just lifted off the Earth’s surface a few minutes prior to the start of ISS’s passage through the penumbra. However, this pass offers the opportunity to see the Sun with “horns” as it sets into the atmosphere assuming an appropriate filter is used to block the Sun’s brightness. At sunset, 27% of the Sun will be covered by the Moon.
All orbit tracks were created using the current ISS orbit ephemeris data. Because of atmospheric friction and other ISS activities, the orbits undergo small changes from week-to-week. The most precise timing information will only be available in the week before the actual eclipse.
Partial solar eclipses have been observed from the ISS many time, because they are not really rare events and the moon’s shadow covers much more surface area when seen from above. But a total solar eclipse is a different ballgame.
More from NASA:
“Observing a total solar eclipse from manned spacecraft is difficult though not impossible. The problem is that Low Earth Orbit platforms such as the ISS and MIR travel at 27,000 km/hr while the lunar shadow travels at about 2,500 km/hr and usually on very different intersecting paths.”
“At a minimum, ISS spends less than 15 seconds traversing the 100-km-wide lunar shadow even when the paths align in space and time. Luckily, ISS astronauts do not have to be right on top of the lunar shadow to see it. From their 400-km vantage point, Earth’s horizon extends about 2,300 km from the ISS. So long as the lunar shadow passes as close as this to the ISS, the astronauts will see in the distance an elliptical shadow near the local horizon, or a nearly-circular shadow in their immediate vicinity. This increases the odds that they will be in the right place at the right time.”
Below are some more views of the moon’s shadow during a solar eclipse captured by astronauts in space.