The Deep Space Atomic Clock (DSAC) is an incredibly small atomic clock, much smaller than any that are currently on Earth. It is significantly more precise than any other atomic clock that has been sent to space and more resilient. Unlike other clocks, which tend to “lose” time, the DSAC is expected to lose no more than 2 nanoseconds of time over the course of a day, adding up to about seven millionths of a second after 10 years.
Atomic clocks are vital to the sciences. If the timing of an event is even a fraction of a second off, it could be catastrophic, at worst, and could spoil scientific results, at best. Atomic clocks measure time by observing atoms that have predicted behaviors, and then calculating how often they repeat them. These devices provide the most accurate time in the world.
Obviously, precision matters when in space. Each and every mission must communicate with ground control, who also rely on atomic clocks to determine how long the signals take to arrive. This information gives them the ability to determine the craft’s position in space, allowing the craft to navigate the vastness of the universe. If the timing is off by even a millisecond, it could impact the mission.
Unfortunately, this process is slow and time-consuming, meaning that the ground crew can only offer assistance to one space craft at a time. By launching the DSAC into space, the crew aboard the craft can make their own measurements, without waiting for any information from ground control. This also allows for the completion of scientific experiments without pausing and waiting for guidance and feedback from Earth. The DSAC is expected to arrive in space with the next Falcon Heavy launch, which is currently scheduled to take place in June of 2018.