Astronomers to Track NASA Juno Spacecraft to Solve Flyby Mystery (Video)

Astronomers may be one step closer to solving the flyby anomaly that has stumped scientists for decades. ESA tracking stations will carefully record signals from NASA's Juno spacecraft as it swings by Earth today at around 19:21 GMT. This could allow researchers to understand an unexplained variation in spacecraft speeds detected during some swingbys.

NASA's deep-space probe is scheduled to zip past our planet to within 561 km as it picks up a gravitational speed boost to help it reach Jupiter in 2016. During this speedy flyby, radio signals from the Juno spacecraft will be carefully recorded.

Since 1990, mission controllers at both ESA and NASA have noticed that their spacecraft sometimes experience a strange variation in the amount of orbital energy that they pick up from Earth during flybys.

"We detected the flyby anomaly during Rosetta's first Earth flight in March 2005," said Trvor Morley, flight dynamics expert at ESA's ESOC operations center, in a news release. "Frustratingly, no anomaly was seen during Rosetta's subsequent Earth flybys in 2007 and 2011. This is a real cosmic mystery that no one has yet figured out."

The unexplained variation is usually noticed as a tiny difference in the expected speed gained (or lost) during the passage. Since the variations are extremely small, it can sometimes not be confirmed. For example, the difference during a swingby of NASA's Cassini in 1999 couldn't be properly confirmed.

This new effort, though, could help matters. Engineers and flight dynamics teams will watch closely as telescopes track Juno. The stations will record highly precise radio-signal information that will indicate whether Juno speeds up or slows down more or less than predicted by current theories. This will potentially help explain what is causing this anomaly, which could help calculations in the future. It won't be easy, though.

"Our Malargue station is designed to track very distant and relatively slow-moving spacecraft, while Juno will pass by moving very, very fast at just 561 km altitude," said Daniel Firre of the ESA in a news release. "This makes tracking Juno technically very challenging, but it's how the scientific process works. Gathering more data that can be analyzed by experts is critical if we are ever to solve this perplexing mystery."

Want to learn more? Check out the video below, courtesy of YouTube.