The Mars One mission aims to establish a permanent human settlement on Mars. Sending messages back and forth to Earth wouldn’t be a problem, though it would be delayed by light speed. But, could these future Mars colonists be able to receive TV channels from Earth?
I don’t mean ordinary broadcasts, of course; I mean, could NASA build a transmitter powerful enough using current technology to send TV signals to Mars that people could actually watch?
NASA doesn’t have anything to do with the Mars One project. It’s being sponsored by a non-profit organization from the Netherlands. In fact, it is being criticized as a scam by most experts.
Assuming it does go as planned, however, according to the article in your link, they plan to have 24/7 communications using two satellites. One will be in orbit around Mars, and the other one will be at the Earth-Sun L4 or L5 point. There’s no reason TV signals couldn’t be sent by satellite, although they would of course be subject to the time delay of electronic signals to reach Mars.
But how much bandwidth is available at that distance? Could you receive a 1080p TV signal? More than one?
The data rate to the Mars Reconnaissance Orbiter (MRO) is up to 6 megabits/sec. That’s enough for one Netflix-quality 1080p stream, though not enough for normal broadcast quality.
However, the options are more limited from the surface. The Curiosity rover can communicate to the MRO at up to about 2 megabits/s. That’s still an OK quality stream, but not 1080p. The rover can communicate directly with Earth, but only at a few thousand bits/s; not nearly enough for TV of any kind.
At any rate, it’s clearly possible to improve on this. With all the other tech that would be needed for a Mars mission, data transfer would not be the most difficult. As cochrane implied, avoiding line-of-sight blackouts through redundancy is the more important problem.
Is this my opportunity to once again pitch the [POST=18517898]Planetary Telemetry and Positioning System?[/POST] (-;
Stranger
I like the proposal, but it seems like power is the killer. Since nukes are a non-starter at the moment, solar is it. Have there been any serious developments in ultra-lightweight, thin-film, inflatable solar arrays?
Of course, beamed power would also be cool, but that seems much farther off.
(BTW, Disney at least knows how to make a cute-looking platypus)
L’Guarde, among others, have been working on inflatable solar arrays for smallsats, but I’m not aware of anything that would be the size to power this system. The two basic opions are a large solar concentrator which inflates a parabolic reflector into a high intensity solar thermal array, or thin film photoelectric panels on an rigidizable inflatable structure that unfolds. To get sufficient area you’d probably need to deploy an array of panels that are strung out using tidal forces to maintain separation and orientation, which is practicable in concept but fraught with potential for failure during deployment. In general, inflatable textiles are difficult just because it isn’t really possible to test them in their operational essentially freefall conditions in a terrestrial laboratory environment, and textiles in general behave structurally in a very nonlinear fashion which makes analytical prediction more of an art than a science. But it is probably the only practical way to launch and deploy a power supply system of this scale in a unitary payload. However, there has been no interest by JPL in pursuing this concept and it died on the vine like so many other proposals.
Beamed power, in general, is most useful in distributed low power applications for small maneuvering satellites for which integrating solar arrays is not practical or desireable. Once the power requirements get to a certain threshold, the amount of area necessary for a receiver rivals the area you would need for a solar power array, so there is no real advantage to beamed power. It wouldn’t be practical for this type of system which requires essentially constant power supply, and would just represent another component with cost and potential failures. The only advantage would be from a maintenance standpoint in not having to deal with aging degradation loss in the onboard solar collectors, but those could be designed for modular replacement over regular intervals, albeit at a non-insigificant cost; assuming that these systems would see regular use it probably makes more sense just to plan for spacecraft replacement with design improvements as the first production block ages out.
Stranger
