Super-antenna could let Mars rover talk directly with Earth
16. 9. 2015 | ExtremeTech | www.extremetech.com
Right now, Mars rovers like Curiosity get roughly 15 minutes to talk to scientists back on Earth, twice per day. If a scientist wants to issue a complex set of orders, or download a whole bunch of new information, it has to all fit into these 15-minute windows.
For scientists on the ground, the necessity of bouncing signals through multiple orbiting satellites means that rover missions progress as a series of quick snapshots, with tense waits in between. Now, they have a prototype for a new and improved type of rover antenna, one that could turn those minutes into hours, and those orbiters into space junk.
The idea comes from a group working on advanced antenna technology at UCLA, in combination with NASA’s Jet Propulsion laboratory. The idea is basically to use an array of 256 antenna elements (a 16 x 16 square) all working together to make a “super-antenna” capable of directly communicating with Earth. Having fewer moving bodies to worry about keeping in alignment, this system could give a rover up to several hours of communication time with operators back on Earth, every day.
The reason it works is not just that the array of mini-antennas creates a more powerful signal, but that the signal is circularly polarized. This has the effect of keeping the signal coherent as it travels through the Martian atmosphere - once a signal gets into the vacuum of space with good signal strength intact, getting the rest of the way to an orbiter around the Earth isn’t hard at all.
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Image Credit: Wikipedia
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