One day traveling around the solar system could be as easy as taking a bus to work. Scientists envision autonomous spacecraft carrying astronauts through deep space and conventional GPS-like systems guiding travelers to other planets and moons. But for those futuristic navigation schemes, spacecraft and satellites would have to be equipped with clocks that measure time with extreme precision, more precise than any clock sent to space so far.
atomic time
NASA’s Deep Space Atomic Clock, or DSAC, counts seconds with about 50 times more consistency and precision than atomic clocks aboard GPS satellites. That’s on par with ground-based atomic clocks used for the agency’s Deep Space Network, the cadre of ground-based facilities that use radio antennas to communicate with missions throughout the solar system. But unlike those refrigerator-sized watches, the DSAC is the size of a toaster and small enough to carry aboard a spacecraft.
Equipped on future spacecraft or satellites, this mini atomic clock could completely change the way we navigate through deep space. After the prototype launches from NASA’s Kennedy Space Center in Cape Canaveral, Florida, researchers will monitor how it behaves in low Earth orbit for a year.
How would the clock change space navigation?
All spacecraft that explore deep space depend on navigation that takes place here on Earth. Ground antennas send signals to spacecraft, which they replicate. By measuring the round-trip time of a signal to within a billionth of a second, ground-based atomic clocks on the Deep Space Network help pinpoint the spacecraft’s location.
With the new Deep Space Atomic Clock, a spacecraft will be able to measure the time it takes for a tracking signal to arrive from Earth, without having to send that signal back to be measured by ground-based atomic clocks. That would allow aircraft to calculate their own trajectory without having to rely on ground calculations.
What are the advantages of one-way tracking?
Having a spacecraft that can track their location would allow astronauts to navigate the solar system without needing instructions from Earth. In a place like Mars, the signal round-trip time can range from eight to 40 minutes, and on more distant planets like Jupiter it can take up to an hour and a half. With a ship enabled to track itself, scouts could execute more agile maneuvers and react more quickly to unexpected situations.
On other worlds, satellites would use onboard deep space atomic clocks to transmit signals with precise timestamps, which could be used by any terrestrial GPS receiver to triangulate their position.
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