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Sunita Williams, a veteran astronaut, was supposed to be on the ISS for only eight days as part of a mission aboard the Boeing Starliner spacecraft.
The sight of 16 sunrises and sunsets from the ISS serves as a stunning reminder of the unique vantage point astronauts have in space.
Can 16 sunrises and sunsets occur in a single day on Earth? The answer is no – at least, not on Earth’s surface. However, this extraordinary phenomenon can be experienced in low-Earth orbit, particularly aboard the International Space Station (ISS). On New Year’s Day, NASA astronaut Sunita Williams experienced this celestial marvel, witnessing 16 sunrises and 16 sunsets in a single 24-hour period. While this is routine for astronauts aboard the ISS, the science behind it continues to fascinate people worldwide.
So, how does this happen? How can one witness 16 sunrises and sunsets in a day? Let’s delve into the science.
What Made This Possible?
The ISS orbits Earth at an altitude of approximately 400 kilometres and travels at a staggering speed of 28,000 kilometres per hour. At this velocity, the space station completes one orbit around Earth in just 90 minutes. This means that the ISS experiences the full cycle of a day – daytime and nighttime – 16 times in a 24-hour period.
If the ISS revolved around Earth at the same pace as our planet’s rotation (once every 24 hours), it would experience just one sunrise and one sunset per day, much like we do on the ground. However, due to its incredible speed and low-Earth orbit, the ISS passes into and out of Earth’s shadow multiple times during a single day. Each time it emerges from the shadow, the astronauts onboard witness a sunrise. Similarly, as it enters the shadow, they see a sunset.
Why Was Sunita Williams on the ISS for New Year’s Day?
Sunita Williams, a veteran astronaut, was supposed to be on the ISS for only eight days as part of a mission aboard the Boeing Starliner spacecraft. However, due to technical issues with the spacecraft, it was returned to Earth without her and her fellow astronaut Butch Wilmore. As a result, Williams’s stay on the ISS extended to more than a month. During this time, she assumed the role of commander of the space station and has been conducting scientific experiments.
What’s Next for Sunita Williams?
There has been much speculation about when Williams and Wilmore will return to Earth. Initially, NASA planned for them to return on a SpaceX spacecraft in September. However, that mission was already scheduled to bring back four other astronauts — two from NASA and two from Russia. To ensure safety and operational efficiency, NASA decided to keep Williams and Wilmore aboard the ISS until the next available flight.
The duo is now expected to return on a subsequent SpaceX mission, which will be arranged soon. In the meantime, they continue to contribute to vital scientific experiments and maintain operations on the ISS, demonstrating the resilience and adaptability of astronauts during extended space missions.
The sight of 16 sunrises and sunsets from the ISS serves as a stunning reminder of the unique vantage point astronauts have in space. It also highlights the engineering marvels of the ISS and the dedication of astronauts like Sunita Williams, who push the boundaries of human exploration and scientific discovery.
