NASA Gets Response From Spacecraft 13 Billion Miles Away

Science Vibe ^ | 18th March 2018 | Stefan Nestorov

[PapaBear3625]

They’re actually re-cycling a Popular Science article from Dec 2017:

https://www.popsci.com/voyager-1-thrusters

[deport]

LOL

[daniel1212]

Its one thing for a radio to wake up after all this time, but how is there any fuel aboard that thing to make a thruster fire? And how does a radio signal travel that far without (or with, for that matter) billions of watts?

Main article: Voyager program § Spacecraft design

The 3.7 m (12 ft) diameter high gain dish antenna used on the Voyager craft

Voyager 1 was constructed by the Jet Propulsion Laboratory.^[12][13][14] It has 16 hydrazine thrusters, three-axis stabilization gyroscopes, and referencing instruments to keep the probe's radio antenna pointed toward Earth. Collectively, these instruments are part of the Attitude and Articulation Control Subsystem (AACS), along with redundant units of most instruments and 8 backup thrusters. The spacecraft also included 11 scientific instruments to study celestial objects such as planets as it travels through space.^[15]

Communication system[edit]

The radio communication system of Voyager 1 was designed to be used up to and beyond the limits of the Solar System. The communication system includes a 3.7-meter (12 ft) diameter parabolic dish high-gain antenna to send and receive radio waves via the three Deep Space Network stations on the Earth.^[16] The craft normally transmits data to Earth over Deep Space Network Channel 18, using a frequency of either 2.3 GHz or 8.4 GHz, while signals from Earth to Voyager are transmitted at 2.1 GHz.^[17]

When Voyager 1 is unable to communicate directly with the Earth, its digital tape recorder (DTR) can record about 64 kilobytes of data for transmission at another time.^[18] Signals from Voyager 1 take over 19 hours to reach Earth.^[3]

Voyager 1 was commanded to change its orientation to measure the sideways motion of the solar wind at that location in space on March 2011. A test roll done in February had confirmed the spacecraft's ability to maneuver and reorient itself. The course of the spacecraft was not changed. It rotated 70 degrees counterclockwise with respect to Earth to detect the solar wind. This was the first time the spacecraft had done any major maneuvering since the Family Portrait photograph of the planets was taken in 1990. After the first roll the spacecraft had no problem in reorienting itself with Alpha Centauri, Voyager 1's guide star, and it resumed sending transmissions back to Earth. Voyager 1 was expected to enter interstellar space "at any time". Voyager 2 was still detecting outward flow of solar wind at that point but it was estimated that in the following months or years it would experience the same conditions as Voyager 1.[53][54]

Power[edit]

Voyager 1 has three radioisotope thermoelectric generators (RTGs) mounted on a boom. Each MHW-RTG contains 24 pressed plutonium-238 oxide spheres.^[19] The RTGs generated about 470 W of electric power at the time of launch, with the remainder being dissipated as waste heat.^[20] The power output of the RTGs declines over time (due to the 87.7-year half-life of the fuel and degradation of the thermocouples), but the craft's RTGs will continue to support some of its operations until 2025.^[15][19]

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[from occupied ga]

and traveling even a few light years is plausible in the near future.

No it isn't. How (other than here a miracle occurs)? Let's do a thought experiment keeping in mind that Newton doesn't go away even at relativistic speed, but to avoid relativity postulate a probe going 1/2 c. Compared to the probe's mass how much energy is required to accelerate the probe to that speed? Answer 1/2 mv² (Newton). Now look at the 2nd law of thermodynamics that says all real processes are inefficient (and the more energetic the process the more inefficient is usually is). Being wildly and completely unrealistically generous and saying that whatever process accelerates the probe is 50% efficient, then the amount of energy required to accelerate the probe is 2*(1/2mv²) = E=mc² (Einsten) which happens to be the total energy equivalent of the mass being accelerated.

It can't carry enough energy even at total mass to energy conversion (not even theoretically possible) to reach that speed. Now if you postulate that some other mechanism accelerated the probe like a cannon shell, then there isn't any way the probe can carry enough energy to ever slow down. Space enthusiasts never think stuff like this though

[from occupied ga]

and traveling even a few light years is plausible in the near future.

No it isn't. How (other than here a miracle occurs)? Let's do a thought experiment keeping in mind that Newton doesn't go away even at relativistic speed, but to avoid relativity postulate a probe going 1/2 c. Compared to the probe's mass how much energy is required to accelerate the probe to that speed? Answer 1/2 mv² (Newton). Now look at the 2nd law of thermodynamics that says all real processes are inefficient (and the more energetic the process the more inefficient is usually is). Being wildly and completely unrealistically generous and saying that whatever process accelerates the probe is 50% efficient, then the amount of energy required to accelerate the probe is 2*(1/2mv²) = E=mc² (Einsten) which happens to be the total energy equivalent of the mass being accelerated.

It can't carry enough energy even at total mass to energy conversion (not even theoretically possible) to reach that speed. Now if you postulate that some other mechanism accelerated the probe like a cannon shell, then there isn't any way the probe can carry enough energy to ever slow down. Space enthusiasts never think stuff like this though

[daler]

Which really hits home what kind of distances we’re talking about when it comes to space travel.

[OldMissileer]

...but how is there any fuel aboard that thing to make a thruster fire?

The spacecraft has two small, sealed tanks. One contains some form of Hydrazine (fuel) and the other Nitrogen Tetroxide (oxidizer) in liquid form. When those two liquids combine they ignite without an external ignition source (they are hypergolic), which makes them extremely reliable. The Specific Impulse for those two liquids is quite high so the thrusters only need to fire a small impulse. The craft only needs to have a very small rotational speed since time is not a factor and then the thruster that is 180 degrees opposite fires to stop the rotation.

Using such small amounts of fuel/oxidizer allows for many years of operation.

[TalonDJ]

“I have a 5 watt hand held 2 meter radio. IF I can hit a repeater, I might hit 20 miles.”

Yeah but that is not LoS. Around here with mountaintop repeaters on big mountains I can hit ones a lot far there a way than that. You can talk to the space station with an HT and that is more like 300 miles away.

[Teacher317]

why is the “Miles away” counting down??

Earth is rotating towards Voyager, and faster than Voyager's speed away from earth. It will change soon, as we rotate in directions that aren't almost directly towards Voyager.

[Teacher317]

Information is exchanged at 160 baud

I remember those days, on dial-up...

[Tijeras_Slim]

So do I, that’s probably why we haven’t heard for Ash, Quidam, and A+Bert for so long.

[Rastus]

You’re overlooking the obvious. An alien engineer figured it out, fueled it up, and fired it up.

[sparklite2]

What is it you’re suspicious of? Requiring V’ger?

[sit-rep]

‘preciate the response! I seen shortly after I asked someone else said the same! I did notice as well the count was screamin forward in the “Distance from the Sun” column... it all made sense then!

[9YearLurker]

I think they could essentially fake UFO reports as verified, since the idea seems to have such appeal of it being what it would take to unite us globally.

I hope that’s not so—but I certainly don’t put it past them.

[Larry Lucido]

Okay, now this post will make more sense, even if no less lame, now that it’s on the correct thread.

*****************

Voyager I calls NASA after 37 years:

NASA, answering the phone: “Hello?”
VOYAGER I: “Hey, it’s Voyager.”
NASA: “Let me put your father on the phone.”
VOYAGER I: “Ma!”
FRANK: “Who is this?”
VOYAGER I: “Dad, it’s me. Hey, listen, I was at Fortuna’s the other day, and, you know what, you were right.”
NASA, feigning a Chinese, muffled voice: “Chinese food.”
FRANK, hanging up: “Sorry, Voyager, our Chinese food just came. Talk to you later.”
VOYAGER I: “Chinese food?”

[sparklite2]

Heh. Very good. V’ger’s not the only struggling with her mission, though.

A Mars Rover’s Lament

All day I faced the Martian waste without the taste of water;
cool water.

At JPL the jerks at work sip Evian: I die for water;
cool clear water.

The nights are cold and I’ve been told each star’s
a pool of water; cool water.

But with the dawn I’ll switch back on
and MastCamBate for water; cool water.

Load an infra-scan; exploration is the plan;
you’re a robot not a man and the broken rocks can stand for water; cool clear water.

MRO, can’t you see that big green tree
where water’s runnin’ free and it’s waiting there for

Error. Stack overflow.

[fidelis]

My late father retired from (Aerojet) Rocketdyne, the manufacturer of these thrusters, and I worked there for 13 years. He spent a lot of years on the manufacturing floor and would have been proud as Punch to hear about this. Rest in peace, Dad.

[OldMissileer]

My late father retired from (Aerojet) Rocketdyne, the manufacturer of these thrusters, and I worked there for 13 years.

Awesome! Prayers and thanks to your Dad and a big "Thank you" to you.

[fidelis]

Thanks OM— Spent some of the best years of my life there. The old rocket factory in Canoga Park, CA was leveled to the ground a couple of years ago to make way for a housing development, and the field laboratory test stands in the beautiful, rugged Santa Susana mountains are being taken down piece by piece to make a State park. But our accomplishments live on.