NASA has a lot spacecraft on Mars that it is a challenge to communicate with all of them, but the technology launched later this month can eliminate the problem in the future.
That technology is Space Atom Clock, a testing system that NASA has developed for two decades. This is intended to help navigate spacecraft and communicate without the need for so much support from Earth. The STP-2 mission, scheduled to be launched on board a SpaceX Falcon Rocket Heavy on June 24, will conduct the first hour test in space.
"Every spacecraft that explores space today relies on navigation carried out on Earth to say where it is and, more importantly, where it goes," Jill Seubert, a space navigator at NASA's Jet Propulsion Laboratory in California , said during a press conference held on June 10. "We have to navigate from Earth because the clock on a spacecraft is really not good at measuring time accurately, but if we can change it, we can revolutionize the way we can navigate deep space."
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And that's where Deep Space Atomic Clock comes in. As atomic clock it will not travel into space, it can measure time to a billionth of a second – but requires space from a gallon jug, not from a refrigerator. Miniaturization means that the instrument can be loaded into the spacecraft and launched.
Once in space, the clock must be able to maintain time accurately without any intervention from Earth. That contrasts sharply with modern clocks GPS satellites, which must be repaired twice a day to stay on time. But maintaining accurate time is very important for spacecraft navigation, said Seubert.
"Tracking a spacecraft while crossing space is basically a problem in measuring time," he said. "We can't just issue a ruler and measure how far our spacecraft is. So instead, we measure how long it takes a spacecraft to echo radio signals sent from Earth."
Radio signals come coded with the exact time stamp when they are produced. And because the radio signals are light waves and the speed of light is constant, this is a direct mathematical problem to solve for the distance traveled by the signal. Signals only need to travel from Earth to spacecraft, and the onboard computer of the spacecraft can navigate itself from there.
This autonomy will offer great benefits for crowded destinations such as Mars and for spacecraft on outer edge of the solar system, where communication back and forth with Earth takes too long to be practical.
Only one or two outposts at NASA's Deep Space Network are communicating with all agency spacecraft that can point to Mars at any given time. And now, the network needs to ping each visitor of the spacecraft one by one to help him stay on track. "All spacecraft on Mars now need to share time tracking with Deep Space Network," Seubert said. "They basically share time."
That's why the ability of atomic clocks to navigate based on simple one-way radio signals is so interesting: All spacecraft on the Red Planet can simultaneously check their location using the same signal, without the need for time sharing. "What this means is that you can basically support the unlimited number of spacecraft going to or around Mars with this architecture," Seubert said.
And the system can also be used by inventors and humans on the surface of Mars or at a more ambitious goal, said Seubert; the system will function like a more exotic GPS form.
"Just imagine an astronaut climbing on Mars, and maybe Olympus Mons rises in the background," Seubert said. "He checked his Google Maps Mars Edition to see where he was and planned the course to reach the goal he had to go."
The scenario is still a long way off, but getting real data about the performance of Deep Space Atomic Clock in space is the first step. After the instrument is safely in orbit, Seubert and his colleagues will confirm that it keeps the time as expected and can last a year in a dangerous space environment, and they will use GPS data to check the reading of the instrument.
Mission Deep Space Atomic Clock costs NASA $ 80 million.
Visit Space.com on June 24 for full coverage of the launch of Falcon Heavy and the STP-2 mission.