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47-year-old Voyager 1 fired up thrusters it hasn't used in decades

cnn.com

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Re: 47-year-old Voyager 1 fired up thrusters it hasn't used in decades

#71

Post by [deleted] »

secondcoming wrote: post #61
Rinzler89 wrote: post #31

Earlier quoted context omitted.

>It's astonishing to me that Voyager knows where Earth is at all It's not that astonishing when you realize astral navigation is what sailors hundreds of years ago did to navigate the seas. Just look at the stars with a sextant and with some basic trigonometry you'll know where you are exactly. The Apollo space crew had to do that by hand and eyes using a sextant too when the astral navigation computer failed.

Does voyager have optical sensors that detect planets?

[deleted]

Re: 47-year-old Voyager 1 fired up thrusters it hasn't used in decades

#72

Post by quesera »

Rinzler89 wrote: post #31
quesera wrote: post #25

Earlier quoted context omitted.

> A radio signal takes more than 22 hours to reach Voyager 1 Voyager has a 23 watt radio and a 14 foot parabolic dish antenna, pointed directly at Earth which is presently 15 billion miles away. The corresponding earth ground station has a 100 foot dish and transmits at thousands of watts. It's astonishing to me that Voyager knows where Earth is at all. I imagine it uses Sol as a reference? Or maybe the high powered…

>It's astonishing to me that Voyager knows where Earth is at all It's not that astonishing when you realize astral navigation is what sailors hundreds of years ago did to navigate the seas. Just look at the stars with a sextant and with some basic trigonometry you'll know where you are exactly. The Apollo space crew had to do that by hand and eyes using a sextant too when the astral navigation computer failed.

It would be astonishing if Voyager shipped in 1977 with computer vision capabilities that were capable of that level of object detection and discrimination and accuracy. Plus the detailed star maps for correlation. And all designed and built several years before launch!

And in fact I think it's not possible. But orienting on Sol should be achievable. Even at 15 billion miles away, it's still surely the brightest thing in the sky.

Presumably the orientation sensor is precisely in line with the parabolic antenna?

Re: 47-year-old Voyager 1 fired up thrusters it hasn't used in decades

#74

Post by quesera »

dcl wrote: post #37
Rinzler89 wrote: post #31

Earlier quoted context omitted.

>It's astonishing to me that Voyager knows where Earth is at all It's not that astonishing when you realize astral navigation is what sailors hundreds of years ago did to navigate the seas. Just look at the stars with a sextant and with some basic trigonometry you'll know where you are exactly. The Apollo space crew had to do that by hand and eyes using a sextant too when the astral navigation computer failed.

Knowing your longitude is very difficult without a clock... Can't do it with just stars iirc.

This is true and there's a fascinating history for Earth-bound (little v) voyagers!

But Voyager does not have this particular problem. :)

Re: 47-year-old Voyager 1 fired up thrusters it hasn't used in decades

#75

Post by quesera »

Intralexical wrote: post #30
quesera wrote: post #25

Earlier quoted context omitted.

> A radio signal takes more than 22 hours to reach Voyager 1 Voyager has a 23 watt radio and a 14 foot parabolic dish antenna, pointed directly at Earth which is presently 15 billion miles away. The corresponding earth ground station has a 100 foot dish and transmits at thousands of watts. It's astonishing to me that Voyager knows where Earth is at all. I imagine it uses Sol as a reference? Or maybe the high powered…

> 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 Space Network receiving station.

And due to the rotation of the Earth, we need three DSN stations to maintain constant communication with Voyager.

Re: 47-year-old Voyager 1 fired up thrusters it hasn't used in decades

#76

Post by rwmj »

ForHackernews wrote: post #42
akira2501 wrote: post #17

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…

> much of the mission's original design documentation remains in paper form and hasn't been digitized.

The cynic in me says this is why the mission has been so successful. Imagine if important documentation had been on some obsolete tape format.

Re: 47-year-old Voyager 1 fired up thrusters it hasn't used in decades

#77

Post by pbronez »

LinuxBender wrote: post #69
piokoch wrote: post #24

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.

You can agree with me or not I agree with you entirely. I can not think of a single piece of tech with the complexity of Voyager that has been battle hardened and resilient to last that long, keep doing what it was designed to do without a major on-site overhaul, upgrade or tech refresh. Certainly not any of our current satellites or anything created since Voyager. I think I know why this will never occur again but t…

> I think I know why this will never occur again but that's a much bigger topic.

I'd read that blog post

Re: 47-year-old Voyager 1 fired up thrusters it hasn't used in decades

#78

Post by [deleted] »

quesera wrote: post #25
yashg wrote: post #6

A radio signal takes more than 22 hours to reach Voyager 1. And it would take the same to get a response back. Incredible. And imagine the patience needed to send commands and wait for the outcome on the part of the engineering team. You can't afford to send a wrong command and have the luxury of undo. Also, I wonder how many generations of engineers must have worked on the project by now.

> A radio signal takes more than 22 hours to reach Voyager 1 Voyager has a 23 watt radio and a 14 foot parabolic dish antenna, pointed directly at Earth which is presently 15 billion miles away. The corresponding earth ground station has a 100 foot dish and transmits at thousands of watts. It's astonishing to me that Voyager knows where Earth is at all. I imagine it uses Sol as a reference? Or maybe the high powered…

[deleted]

Re: 47-year-old Voyager 1 fired up thrusters it hasn't used in decades

#79

Post by HPsquared »

quesera wrote: post #75
Intralexical wrote: post #30

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…

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?

Re: 47-year-old Voyager 1 fired up thrusters it hasn't used in decades

#80

Post by HPsquared »

unwind wrote: post #52
Aachen wrote: post #49

Earlier quoted context omitted.

$ 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)

Probably ounces ("oz") for something like this, so around 0.005 oz then. The original 100 kg is equivalent to 220.5 lbs (which is pronounced "pounds", of course).

147 mg is about 2.27 grains
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