Laser communication systems
Lasers could one day carry interplanetary communication signals between Earth and Mars.
Current Mars rovers and satellites send and receive signals from Earth via radio waves at a data rate of a few megabits per second[1]. If lasers could be used instead, the transmission would form a tighter beam, with more of the total energy being delivered to the receiving antenna and less wasted. This means a higher data rate, for the same power consumption[2]. With current technology, at Earth-Mars range, a laser could increase bandwidth by a factor of 10 compared to radio waves, making high-definition video streams possible. Future refinements in the technology could lead to a data rate 100 times that of radio waves[1].
Laser communication has never been tried at this distance. NASA plans to test long-distance communication using an infrared laser in conjunction with an upcoming mission that will send a probe to an asteroid, scheduled to launch in 2022 and arrive at its destination in 2026.
A new Deep Space Network antenna currently under construction will have dual functionality for both radio and laser signals[1].
Engineering challenges for Earth-Mars laser communication include interference from sunlight, precise pointing of the narrow beam despite spacecraft motion and vibrations[2], interference from Earth's atmosphere, space temperature extremes, radiation, and forces on delicate equipment during launch[1].
Lasers on the ground may be scattered by Dust storms, where as radio waves are not effected. If the laser was in orbit, then this is a non-issue.
Alternatively, if enough power is available, radio communications may continue to be used for high bandwidth communications. In particular if cheap space transportation allow for the launch of dedicated orbit communication satellites rather than the use of Earth ground stations. Large and powerful satellites could also be installed in Mars orbit.
References
- ↑ 1.0 1.1 1.2 1.3 Carter, J., 2020, NASA Will Soon Use 'Space Lasers' To Give Us Live Video From Mars And The Moon, Forbes, https://www.forbes.com/sites/jamiecartereurope/2020/02/11/how-space-lasers-will-bring-the-solar-system-its-broadband-moment-and-live-video-from-mars.
- ↑ 2.0 2.1 Seffers, G.I., 2018, NASA Counts Down to Laser Communications for Mars, SIGNAL Magazine, https://www.afcea.org/content/nasa-counts-down-laser-communications-mars.
