how is it possible for NASA to establish a signal/connections so far in outer space but we can’t find signals in certain rooms in our homes?
In: Physics
Their instruments are significantly more sensitive and specialised than the mass-produced router with Wi-fi you got for free when you signed up for broadband. NASA will also have spent slightly more on their equipment (ie millions) than you.
NASA can afford a large electricity bill. Lower bill would definitely be great since congress likes cutting their funding, and they definitely do their best to lower it, but what needs to be done will be done.
Space is pretty empty. Not much to block the signal.
They know where the signal needs to go or is coming from. They can point their satellite dishes exactly where they need to be. We could put motorized satellite dishes on our routers and track our phones, but that’d just be ridiculously expensive and fragile.
Not many people are trying to communicate with things in deep space, so the airwaves aren’t exactly crowded.
NASA’s stuff don’t need to look nice. They can be as clunky as they need to be to function. All of our devices are hiding their antennas so we can have nice, neat rectangles.
Comparing NASA’s [Deep Space Network](https://en.wikipedia.org/wiki/NASA_Deep_Space_Network) to commercial WIFI or cellular technology is comparing apples and oranges. NASA has a global network of gigantic (70m/230ft wide) radio telescopes that send and recieve powerful signals (up to 400 kilowatts) in narrow beams that must be carefully aimed, and their space probes likewise have gigantic antennae that send and recieve in one direction.
For example, NASA was able to maintain a connection with Curiosity Rover on Mars and receive images taken by it.
Also the Cassini (I think it was called) took a photo of Earth so far away in the rings of Saturn and sent it back to Earth.
How is this sort of connection possible?
Are there satellites in outer space that are just really strong?
If you take the entire spherical coverage around your wifi router, and concentrated it into a tight beam which was always directed straight at your phone, you could probably make it quite a ways from your house and still receive signals from (note: but not necessarily send to) your router. The fact that the signal strength is being diluted by being omnidirectional is part of it.
Another part of it is how empty space is. It’s a lot easier to transfer electromagnetic signals across (almost) nothing than it is through solid matter, like your home is made of. Specifically certain arrangements of metal are ideal shielding against it. The netting on the door of your microwave oven, for instance, perfectly blocks out the wavelength of electromagnetic radiation that the emitter is using to heat your food.
There are two main reasons for this.
The first is simply a matter of the quality of equipment, NASA has a budget in the billions and uses transmission equipment that requires acres of land. That equipment is designed with an effectively unlimited budget to send a signal to mars. Your Wifi router is designed to cost less than $100, fit on an end table and do the best it can within those parameters.
The second is the fact that it’s in space, which is filled with, well space. Your house has walls, which block signal, and those walls have wiring and other metal components, which severely block signal, whether it be from Wifi or cell towers. This is why a metal shed, even with thin walls, tends to wreck cell reception. NASA has (almost) perfect line of sight through space to whatever it is trying to contact because there is (almost) nothing in space between it to distort or block the signal, so even though it takes time to travel over the distance, it’s much more comparable to you standing outside for cell signal or within line of sight to your wifi router.
Plenty of people have mentioned the difference of equipment, but the main factor is that electromagnetic waves transmit indefinitely through the vacuum of space, and without much, if any, interference.
Your house is full of wood, metal, insulation, and plaster, which get in the way, and also cell phones, game controllers, a microwave oven and maybe a baby monitor that all emit similar signals.
I remember someone commenting that between the voyager & world, there is less material compared to you and the phone in the next room.
Many people here have mentioned how signals can travel easier through vacuum and are sent with higher power than usual, but there is another much more important technique – forward error correction.
Imagine that you wanted to send the message 001001 between two mountain tops by voice during a windy or noisy day. If you just shouted “ZERO” or “ONE” some of those might get missed or swapped but if instead you shouted a sequence representing zero like “CAT DOG MOUSE FISH BIRD” and a sequence representing one like “BLUE RED GREEN YELLOW ORANGE” you dramatically raise the chance of the other person hearing one of those words and if they all are unique and the order is known, you can reconstruct the message easily even with little information actually received.
It is important to note that you absolutely destroy the rate of information transfer to gain improvements in noise reduction. There are many techniques like this that NASA uses for error correction to ensure that the data they get arrives without error, without requiring much much larger receivers and transmitters than required.
I worked on a program that was targeted design a transmitter capable of sending 1ish watt (1/1000th the power of a microwave) signals from Alpha Centauri back to our solar system – a distance of 4.367 Light Years or 25.67 trillion miles.
WiFi uses [these](https://www.tdtprofesional.com/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/a/n/antwifiqviart_foto.jpg). They’re omnidirectional and the ones meant for home use transmit at a tenth of a watt, give or take.
NASA uses [this](https://www.researchgate.net/profile/Mark_Johnston7/publication/242559177/figure/fig1/AS:298447807762432@1448166910147/The-70m-antenna-at-the-Goldstone-DSN-complex-in-California_Q640.jpg) (along with a bunch of other dishes “only” half the size of this thing). It’s quite directional and transmits at around **twenty thousand** watts.
The power difference alone makes the big dish hundreds of thousands of times more powerful, and it also only points at a certain part of the sky so it doesn’t waste energy by radiating it all over the place.
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