I am amazed. Ok, so that nothing new, cz I am not a scientist and so get amazed easily by some of these scientific thingies. What I am amazed today is to find out that the distance between the Earth and Mars is about 35 million miles. Well, thats not really why I am amazed, actually.
Its the fact that the scientists sitting in NASA’s Jet Propulsion Laboratory somewhere in US are able to control the Spirit Rover through a remote control. 35 Million Miles?? Wow! What kinda radio technology works that far in space?
I look at my TV’s remote which doesn’t work from 5 feet away if I am not pointing it directly towards the television. These NASA scientists surely know their stuff
You'd sure me pissed if you pressed your channel change button and it took 20 minutes to complete the command. I think it involves a lot of patience too.
I'm waiting for the day they actually get there in orbit at least and remote fly a drone through the martian skies, thats a little more troublesome from earth.
Its the fact that the scientists sitting in NASA's Jet Propulsion Laboratory somewhere in US are able to control the Spirit Rover through a remote control. 35 Million Miles?? Wow! What kinda radio technology works that far in space?
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In space radio waves travel much further because there are on obstacles. They might have some satellite in orbit around mars with powerful transmitter as a relay station.
As Abdali says, the distance is no problem cos all you need is a strong power source to create the radio waves. The main issue with such long-distance communication is being able to clear out the noise from background radiation waves from your radio communications. Recent improvements in computing power have enabled this.
It depends on the wavelength and frequency of transmitted waves...along with the technique being used for modulation of waves...
secondly the main thing is output power of signals... more the power more the penetrating ability ...
Power of signal directly proprtional to Distance
I am sure the signals from Mars are not directly being received on earth from... those signals must be transmitted to any space station or satellite and then boosted again towards earth!
Mars <--> Satellite <--> Earth
The medium in space has less magnetic and electric filed hence less interference, so less chances to for being lost for the signals... then afterward same receiving technique!
35 Million Miles distance away how much time it will take the signal from earth(satellite) to mars and then the feed back.
-are they converging the waves in beam form like laser to increase signal penetration?
Change the battery of yer remote control. Yes, you have to POINT towards the TV, thats how these Infra-Red transmitters/receivers work. BTW, these “universal communications” also need the “beam-forming” so the transmit-power is focused in the direction of “target”. Other communications like Cell phones don’t use such POINTED communication… the antennas form BROADer beams to cover particular geo-region.
If they can calculate the position of Mars, won’t they be able to calculate where to point there antennas?
Hmm.. 35 Million miles... a large distance to travel as it seems... but not a very big deal for radio signals.. mind it it takes about 15 minutes in which a radio signal is transmitted gets to the prob orbiting around MArs... all they need a powerful transmiter... in this case a 20W transmittter is enough for this distance... In satellite communicatiion you also need to point towards the probe, not because you must, but because of transmiting power optimisation...you can acheive the same results just by transmiting a signal in any direction but then you need massive transmiter... simplest example is Sun and a tourch... sun light travels in all directions hence need a massive light source, on the other hand a tourch is used to brighten just a specific area, as required......
the main problem is Modulation and then Demodulation of the signal, normaly three techniques are used for this purpose...
I think a simple scientific class is in order here...
So at what speed the radio signal travels in space when it is sent from a 20W tranmisttor? Speed as in miles/second or something which I can understand.
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*Originally posted by Faisal: *
I think a simple scientific class is in order here...
So at what speed the radio signal travels in space when it is sent from a 20W tranmisttor? Speed as in miles/second or something which I can understand.
Thanks.
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almost same as the speed of light... which is 3x 10^8 meter/second... and signal strength has nothing to do with transmiting power... its same for 1mW or 20KW transmiter... in great distances signal will simply fade away.
Hey hey.. I dunno this wattage thingie (I only know that 100w Philips bulb is for reading and 40w is for everything else, pretty much). Anyway, someone up there mentioned that a 20W transmitter will be enough to send a message through space to Mars, so I just kept that assumption.
Change the battery of yer remote control. Yes, you have to POINT towards the TV, thats how these Infra-Red transmitters/receivers work. :)
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IRs work on line of sight, UHFs are much better.
Another interesting question that popped up while I was working the other day, and got the senior project engineer baffled too...
We were installing an infrared heat sensor module in a vacuum inside a motor, now heat needs a medium to propogate, would the IR sensor (thats infra red) work or not? Very interesting answer to this one.
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*Originally posted by dejavu: *
Another interesting question that popped up while I was working the other day, and got the senior project engineer baffled too...
We were installing an infrared heat sensor module in a vacuum inside a motor, now heat needs a medium to propogate, would the IR sensor (thats infra red) work or not? Very interesting answer to this one.
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It should work. Infra-red is a form of low-frequency radiation, which can propgate easily as easily in vacuum as in a medium.
It's just like visible light. Infra-red radiation is just off the lower end of the light frequecies that the human eye can see. Like visible light travels through a vacuum, so does infra-red.
