Humans have visited Earth’s moon, sent robotic spacecraft to the seven other known major planets of our solar system, and even as far away as the distant dwarf planet Pluto. But, navigating in deep space still remains a daunting challenge.
To precisely determine the position and velocity of a spacecraft far from Earth, navigators must transmit radio signals to the spacecraft from giant dish antennas on the ground, which the spacecraft receives and repeats back. The time the signal takes to return is measured by super-accurate atomic clocks on the ground.
These clocks, about the size of a refrigerator, use vibrating atoms to tell time accurately to within a few trillionths of a second. When the spacecraft is far away, this method of fixing its position can take several hours. For a spacecraft at Saturn, for example, a signal from Earth takes more than an hour just to reach the spacecraft, and for Pluto, almost seven hours.
In 2021a team of NASA researchers reported a breakthrough that could make deep space navigation much simpler. The researchers successfully tested a new kind of miniaturized atomic clock aboard an orbiting satellite. The new clock is only about the size of a toaster, and uses electrically-charged atoms trapped in an electrical field to tell time. Using electrically-charged atoms makes it more stable than traditional atomic clocks that use neutral atoms.The researchers showed that even under the rigors of spaceflight the new clock may be as accurate as its much larger cousins on the ground. When carried aboard a spacecraft in deep space, the new clock will make navigation simpler and much faster. This will make far-off spacecraft more self-sufficient.