81–90 of 91 posts
Earlier quoted context omitted.
About 680 thousand puffs so far (40 x 365 x 47). Also, "When the team initially switched Voyager over to the trajectory correction thrusters six years ago, the tube opening was 0.01 inches (0.25 millimeters) across".
$ qalc > 100 kg / 680e3 approx. 147.06 mg Each puff would be (Not sure what the USA weight unit is, stones or something? DDG says that's 0.000024 stones)
You can agree with me or not, but Voyager 1/2 is a top technological achievement of the humankind. A piece of hardware so good that it survived working correctly 47 years in a hostile environment, driven by a computer with the power of modern car key. Amazing.
>driven by a computer with the power of modern car key I appreciate the sentiment, but perhaps it is the car key which is impressive here...
Earlier quoted context omitted.
You characterize every single piece of equipment on platform so you can do somewhat accurate simulations. The shuttle flew most of the critical phases of their missions on the ground before ever uploading the code into an actual shuttle computer. The simulation system was continuously updated with real world performance information so it's accuracy continually improves. You also have a command processor on the spacec…
> You characterize every single piece of equipment on platform so you can do somewhat accurate simulations. The shuttle flew most of the critical phases of their missions on the ground before ever uploading the code into an actual shuttle computer. The simulation system was continuously updated with real world performance information so it's accuracy continually improves. This is not true of the Voyager probes: > New…
As opposed to many other modern missions this craft is just flying for distance. It doesn't have to land anywhere or perform any complicated maneuvers. So a standing ground test platform wouldn't be particularly useful. The shuttle, our landers, and probes are obviously a different story.
You can agree with me or not, but Voyager 1/2 is a top technological achievement of the humankind. A piece of hardware so good that it survived working correctly 47 years in a hostile environment, driven by a computer with the power of modern car key. Amazing.
Earlier quoted context omitted.
Which correspondingly means that the received signal strength here on Earth is very low . Internet says approximately -160.48 dBm, which is one thousandth of the minimum strength that the most sensitive commercial FM radio receivers can discriminate. Hence the huge receiving dishes, and apparently one 100 foot dish alone does not collect enough energy to reconstruct the signal, so multiple are required at each Deep S…
I wonder if they could build a very large dish in Earth orbit. Probably cost prohibitive though. Also there's the power and cooling aspect when transporting... Would there be any advantage to a space based station?
Two obvious issues spring to mind;
The orbit would need to be polar to avoid being blocked by the earth (assuming the craft is in the solar plane). Whatever orbit was chosen at least some planes some of the time would be obscured by the earth.
And orientation fuel becomes an issue. Outside of refueling it becomes a hard end-of-life factor.
Contrasted to land-based stations. Which are happily operating 50 years and can be maintained etc.
Frankly I'm not sure there would be any advantage to a space receiver- and it's several orders of magnitude more expensive.
Earlier quoted context omitted.
> It's astonishing to me that Voyager knows where Earth is at all. Wikipedia says that the high-gain antenna has a beamwidth of 0.5° for X-band, and 2.3° for S-band. You have: tan(0.5deg/2)*2*164astronomicalunit You want: astronomicalunit * 1.4311791 So it's so far that you could almost point it straight at the sun, and have the entire orbit of the Earth in the beam. 23 watts, spread out in a cone the size of a plane…
Which correspondingly means that the received signal strength here on Earth is very low . Internet says approximately -160.48 dBm, which is one thousandth of the minimum strength that the most sensitive commercial FM radio receivers can discriminate. Hence the huge receiving dishes, and apparently one 100 foot dish alone does not collect enough energy to reconstruct the signal, so multiple are required at each Deep S…
Around 30k photons a second.
You have: ((23W/(pi*astronomicalunit^2)) * (pi(50ft)^2)) / (6.626e-34J/Hz * 10GHz)
You want:
Definition: 36024.297 / s
Earlier quoted context omitted.
Which correspondingly means that the received signal strength here on Earth is very low . Internet says approximately -160.48 dBm, which is one thousandth of the minimum strength that the most sensitive commercial FM radio receivers can discriminate. Hence the huge receiving dishes, and apparently one 100 foot dish alone does not collect enough energy to reconstruct the signal, so multiple are required at each Deep S…
I wonder if they could build a very large dish in Earth orbit. Probably cost prohibitive though. Also there's the power and cooling aspect when transporting... Would there be any advantage to a space based station?
Earlier quoted context omitted.
I wonder if they could build a very large dish in Earth orbit. Probably cost prohibitive though. Also there's the power and cooling aspect when transporting... Would there be any advantage to a space based station?
I'm no space expert, but I'm not sure this would be say better. It would certainly be epically more expensive. Two obvious issues spring to mind; The orbit would need to be polar to avoid being blocked by the earth (assuming the craft is in the solar plane). Whatever orbit was chosen at least some planes some of the time would be obscured by the earth. And orientation fuel becomes an issue. Outside of refueling it be…
Actually, microgravity means you could have a 50-meter dish unfold neatly from a backpack-sized wad of Mylar.
Earlier quoted context omitted.
Which correspondingly means that the received signal strength here on Earth is very low . Internet says approximately -160.48 dBm, which is one thousandth of the minimum strength that the most sensitive commercial FM radio receivers can discriminate. Hence the huge receiving dishes, and apparently one 100 foot dish alone does not collect enough energy to reconstruct the signal, so multiple are required at each Deep S…
> Hence the huge receiving dishes, and apparently one 100 foot dish alone does not collect enough energy to reconstruct the signal Around 30k photons a second. You have: ((23W/(pi*astronomicalunit^2)) * (pi(50ft)^2)) / (6.626e-34J/Hz * 10GHz) You want: Definition: 36024.297 / s …I don't know if that's a lot, or where the noise floor is.
> For example, the data rate used from Jupiter was about 115,000 bits per second
And I think it affects the calculation slightly that Voyager's downlink transmits at about 8.4 GHz (X-band).
Good stuff here: https://www.allaboutcircuits.com/news/voyager-mission-annive...