With the combined help of NASA’s Cassini spacecraft and Very Long Baseline Array (VLBA) radio-telescope system belonging to the National Science Foundation, scientists managed to pinpoint the position of Saturn and its orbiting moons to within 2 miles. The team will present their findings today Jan.9 at the American Astronomical Society’s meeting in Seattle.
This is the first time researchers managed to determine a planet’s position with such great precision. The calculations were done by a team of scientists from NASA’s Jet Propulsion Laboratory in Pasadena, California and from the National Radio Astronomy Observatory (NRAO) in Socorro, New Mexico. The results are 50 times more accurate than the values determined by optical telescopes on Earth. This method of locating planets will improve basic physics research and future space travels.
The VLBA is actually a group of radio-telescope antennas, positioned in different locations varying from Hawaii to the Virgin Islands. The array was used by scientists to determine the precise location of Cassini as it was orbiting Saturn. During the last 10 years, the spacecraft’s radio transmitter would send signals received by the array of antennas back on Earth. By combining the signals with data regarding Cassini’s orbit (acquired from NASA’s Deep Space Network), the team managed to calculate the position of Saturn’s barycenter which is a planet’s center of mass, then proceeded to calculate the barycenter of each of the saturnian moons.
The research was possible thanks to the spacecraft’s long-term presence around Saturn and due to VLBA’s capability of distinguishing very fine detail. The calculations helped astronomers improve the ephemeris which is one of the basic tools in astronomy, a table of predicted locations in space.
As lead researcher Dayton Jones of JPL said:
“This work is a great step toward tying together our understanding of the orbits of the outer planets of our solar system and those of the inner planets.”
This new method will improve navigation between planets and help determine a more precise mass of objects in the Solar System. The “improved positional information “ even contributed to the analysis of Albert Einstein’s theory of general relativity as scientists are now able to observe small changes in the alleged positions of active black holes or quasars by comparing their position to that of Saturn’s.
The new determined ephemeris will help “steer” the spacecraft easier. The team will continue observing Saturn until the mission ends in 2017. Also, they plan on using this technique to monitor the trajectory of NASA’s Juno spacecraft when it will reach Jupiter in 2016.
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