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H. de Jong
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Comments by "H. de Jong" (@h.dejong2531) on "NASA Reestablishes Contact With Voyager 2! Where Is It Headed Now?" video.

We didn't lose contact. Every day, we kept receiving data from Voyager 2. The only thing we couldn't do was send new commands to Voyager 2 because the transmitter was being replaced. 3:38 Currently, tape recorder playback is done at 1400 bits/s. This occurs once every 6 months. Playback at this speed requires the use of an array of a 70 m antenna with 3 34 m antennas, i.e. all of the large antennas at a DSN complex. 9:50 Each of the three DSN complexes has one 70 m antenna, not just Goldstone. 10:38 Voyager 2 is visible only from the Canberra DSN complex, because the spacecraft is South of the ecliptic plane. The transmitter on the 70 m antenna (DSS 43) at Canberra had to be replaced. And why are you showing random clipart instead of a photo of the actual antenna?
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JHUAPL is working on an interstellar mission concept at the moment. The highest speed they've been able to get to using current technology is about twice as high as the Voyagers. It would take decades to catch up to the Voyagers at that speed.
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We have no indication that the edge of the observable universe is the end of the universe.
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The spacecraft are identical, their missions were different: Voyager 1 visited Jupiter and Saturn, and did a flyby of Titan which meant it couldn't continue on to Uranus. Voyager 2 visited all 4 gas giants.
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After the Voyagers, we switched to missions that explore one planet in more detail, like Galileo at Jupiter and Cassini at Saturn. The only recent flyby mission is New Horizons (Pluto and Akkoroth).
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@fromnorway643 They're really bright in the IR though (2 kW power source). A radio telescope can see Voyager's 20W transmission. It'll be close to the edge of what JWST can see, but I think it's possible.
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@timhochstetler3440 The position of those moons relative to the planet dictated the paths they would take. Those paths were known beforehand: they had to aim the spacecraft precisely before the encounter, so that the planet's gravity would bend the trajectory by just the right amount to do a flyby of the moon they were aiming for. So even before the encounter they had a pretty good idea in which direction the spacecraft would go, and immediately after they confirmed that by measuring the trajectory precisely.
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If power weren't a problem, the current DSN could stay in contact with them until 2057. Longer if they'd use radio telescopes (like the VLA, which was used to support the Neptune encounter).
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@stevewalker412 I'm looking at the specifications of the Voyager communications system right now; the loss due to the atmosphere is less than 1 dB, that's almost negligible. That's in clear weather: when it rains, losses are higher. On Earth, we can build a 34 meter antenna for about $50M. The largest antenna ever sent to space is about 10 meters across, and a spacecraft that can run it costs several hundred million dollars.
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The Voyagers are about 20 light-hours away. We wish we could build spacecraft that can travel lightyears.
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yes, that's correct.
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Some crazy entrepreneur is privately building a rocket more capable than the Saturn V at the moment. NASA built the New Horizons spacecraft which is comparable to the Voyagers, and our current Mars missions are a lot more capable than the Vikings.
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They used Pu-238 because it's an alpha emitter. Moreover, the entire decay chain is via alpha emission. A sheet of paper will stop all of the radiation from the Pu elements. They are encased in several layers much thicker than a sheet of paper, so they'd have to disassemble the RTG completely to be exposed to radiation. Any civilization advanced enough to operate in space will know about radiation. And last, by the time the Voyagers get anywhere near a star, the entire RTG will have decayed all the way to non-radioactive lead.
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it's not traveling through time. The Voyagers are so far away light (and radio signals) take about 20 hours to travel from Earth to Voyager, but we've built ground stations that can handle that.
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The power source is nuclear (Plutonium-238 decays which produces heat, thermocouples convert that heat directly into electric power). The spacecraft were built with lots of flexibility and redundancy, and the best components were used throughout. Even so, quite a few of those redundant components have failed, and Voyager 2's receiver isn't working well (but we can compensate for that by changing our transmissions).
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The Voyagers can't, but New Horizons is doing that at the moment.
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Yes. Voyager 1 was sent North of the ecliptic plane (=the plane in which the planets orbit) from Saturn, Voyager was sent South from Neptune.
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The Voyagers used 3 computers (CCS, FDS, AACS), all custom designs (the CCS was used earlier on the Viking Mars landers).
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@williamwalker6071 Yes, on Voyager 1 the DTR is still operational (last I checked, in January this year). On Voyager 2 it was switched off after the last instrument that could use it, failed.
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The radio link isn't the limiting factor. The Voyagers are running out of power: in about 2 years, there's not enough power left to run a single instrument. Our current communications system would be able to stay in contact with the Voyagers until 2057 if the Voyager power source lasted that long.
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That's an animation, obviously.
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It's not at -200. Heaters in the spacecraft keep the vital components near 0 ºC.
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The power source supplied 470 W at launch, and produces about half of that now (~250 W, dropping by 4 W/year). The RTG produces a lot of heat (more than 1 kW). There are also radioisotope heater units in the spacecraft. The transmitter transmits at 12W or 18W of radiated power, using 50-70W of input power. The antenna diameter is 3.6 m, antenna gain is 48 dB at X-band. Details can be found in Descanso 4, a JPL document that describes the Voyager telecommunications system. The main reason we can still communicate with the Voyagers is at the receiving end: a 34 m antenna with a cryogenically-cooled receiver, which has no trouble receiving the -160 dBm signal from the Voyagers at 160 bits/s.
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NASA's Voyager Mission Status page keeps track of that.
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no. They're too small and dim.
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Earth gets hit by about 5000 tons of meteors per year. Divide that by Earth's surface area, and it works out to micrograms per m^2 per year. And Earth is a worse environment than deep space. So the odds of a spacecraft not surviving are about one in a billion. Not magic, science.
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@edward4258 This is based on several sources: 1. amount of meteors found on Earth. We've done systematic searches and can extrapolate from that. 2. Observation of meteors as they enter our atmosphere and leave bright trails. 3. our experiences running about 9000 satellites in Earth orbit, and several hundred missions all over the solar system. Including a series of missions specifically designed to measure the amount of debris.
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@edward4258 These observations and measurements have been published the usual way (in scientific journals, many of which are accessible to the common man). We also see the result: satellites and deep space missions continue to function for decades without significant damage. These observations were made not by one entity, but by dozens of space agencies from different countries, along with dozens of commercial companies whose income depends on that data being correct.
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@edward4258 5000 tons are divided over Earth's surface (an area of 10^20 m^2), that's 10^-11 grams per m^2 per year. Most space dust consists of tiny particles, which leave tiny craters or pinholes in the outer shell of a satellite. So over time, we see damage accumulating. Solar panels will degrade over time, for example. There's an element of luck to this: a meteor that weighs 100 g would destroy a satellite, and we can't track every piece of debris that small yet. But since 1957, we haven't lost a single satellite though meteor impact. We've lost 2 satellites that collided with each other, and a few were intentionally destroyed by antisatellite weapons.
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@edward4258 These are not my estimations. This is my summary of actual studies done by space agencies over the past 60 years. Studies that have been published, and which I've read. They take into account that most debris doesn't reach Earth's surface intact. I'm not asking you to trust me, I'm saying the data is available for anyone.
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@edward4258 On one side we have multiple independent parties doing research and presenting their findings, from raw data to methodology to conclusions. On the other side, we have you saying "I don't believe all that research, but I have no data to support my position". If you want anyone to believe you, you need to come up with data, otherwise it's a much greater leap of faith to believe you than it is to believe the people actually running these spacecraft. There are several methods anyone can use to measure meteor flux: 1. point a camera at the sky, count meteor streaks. 2. go somewhere cold, dig out a few m^2 of snow and count meteorite dust embedded in the snow. 3. monitor satellites. This is easiest for TV broadcast sats, but you can receive data from many satellites with a ham radio setup. This can be used to verify if a satellite is active or defunct.
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@edward4258 So you read one book that selectively interprets its source data. Meanwhile, you are claiming all data supplied over a period of 60 years by multiple parties is false, despite you having no data at all to support your position.
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@edward4258 There's a big difference. In your book, someone took the results of a study (probably along the line of 'chemicals x, y and z were found in the soil here) and concluded 'it must be aliens'. There's a big gap between data and conclusions. When it comes to space dust, we have multiple studies done by different parties that all gave consistent results, and about 11,000 experiments done over 65 years to validate that data. This is the scientific method: you do observations, you create a hypothesis, and then you test if that hypothesis makes accurate predictions. Your book stops at making a hypothesis. It doesn't do any experiments to validate the hypothesis, it doesn't gather additional data. For space dust, we've done a large number of tests that confirmed the hypothesis. If you want to question this hypothesis, go ahead, but you'll have a difficult job: you have to prove all that data incorrect. If you do that, scientists will take you seriously. Just saying "I don't believe it" without any data to back you up won't cut it.
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@edward4258 So you want me to provide evidence, and when I refer you to the studies that contain the evidence, you're saying "nah, I'm not going to bother with them because I've already decided I don't believe what they say". That's not my problem, it's yours.
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Because Venus is under continuous cloud cover. It's much easier to build solar power stations in Earth orbit. We'd still have to solve the problem of transmitting that energy to the ground.
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Russia focused on Mars and Venus, and struggled to build interplanetary spacecraft that kept working for very long. Their Mars probes kept malfunctioning even before they reached Mars.
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It's much cheaper to build larger antennas on Earth than to launch them into space. It's also more efficient: an antenna on Earth can support spacecraft on any trajectory, while a relay launched in the same direction as one of the Voyagers would only be able to support 1 spacecraft.
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@JoeGator23 On Earth, we can build an antenna with a diameter of 34 meters for about 50 million. These antennas are capable of talking to a Voyager-style spacecraft at a distance of about 200 AU (Voyager 1 is at 150 AU now). The largest antenna we've seen in space so far is the Spektr-R radio telescope, with a diameter of 10 meters. A relay spacecraft that can function outside of Jupiter's orbit will cost on the order of a billion dollars, so we could build 20 antennas on Earth for that. We're going to lose contact with the Voyagers because their power source is degrading, in a few years there isn't enough power left to operate one science instrument. JHUAPL is working on a proposal for a next-generation interstellar probe, the main problem is that this probe needs to be a lot faster than the Voyagers. Even with the best rockets we have today, we can only reach 2x the speed of the Voyagers.
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@JoeGator23 The Voyagers gained about 10 km/s from each of their slingshots around Jupiter and Saturn, and 2 km/s for Uranus and Neptune. They arrived at Jupiter at 10 km/s, so that first slingshot doubled their speed.
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it's much cheaper to build a giant antenna here on Earth than to build one in space.
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That was actually considered. The JHUAPL Interstellar Mission is a current study for a fast probe to outside the heliosphere. One option they considered was a close flyby of the Sun for a gravity assist. Unfortunately, the shielding required for this added so much mass that the net effect was too small to be usable.
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Space is very, very empty. The average density out there is 1 atom per cm3. Even in the densest part of the solar system (the asteroid belt), there was only a 1 in 1 billion chance of hitting something.
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After the Voyagers, we switched to missions that orbit one planet to study it in far more detail than a flyby ever could: Galileo and Juno at Jupiter, Cassini at Saturn. New Horizons to Pluto is the exception (a mission that can enter Pluto's orbit would have been very expensive).
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no, the Voyagers are too small and dim for that.
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It's not seeing anything, because the cameras have been switched off. We've been learning a lot from the instruments that are still working though.
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14.4 and 12 billion miles (see the Voyager Mission Status page).
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Voyager can't be used to search for planet 9. Its cameras are not well-suited for imaging faint objects, and the spacecraft no longer has enough power to operate the cameras. Other instruments don't help with this either. The course of the Voyagers was determined by their last planetary flyby: Voyager 1 had to do a close flyby of Saturn's moon Titan, which determined the angle at which it exited the Saturn system. The same goes for Voyager 2 and Neptune. Any stars along those paths are incidental.
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Yes, people believe it because it's true. The only people who think NASA is based in Hollywood are people who distrust the government, but are extremely gullible when fed crap by charlatans.
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The trajectories of the Voyagers were set by the flybys: Voyager 1 had to visit Saturn's moon Titan, this determined the direction in which it would leave the solar system. Any stars along this trajectory are coincidence. Voyager 2 had to fly by one of Neptune's moons.
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No, we just have to accept science to believe we can communicate with such a device. Specifically, the equations that govern electromagnetic waves, which give us the exact parameters we need to communicate over that distance. It turns out, all you need is a large antenna (we have those: the DSN was built for this, with antennas 70 meters wide) and a receiver cooled to near absolute zero (DSN has those too). In fact, the antennas have enough margin that we could communicate with a Voyager type spacecraft at a distance of 200 AU.
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@WSCLATER I'm not saying that at all. The equations that govern electromagnetic waves can be easily verified here on Earth, and have been verified thousands of times. Every radio on Earth uses the same principles. We also have independent verification the Voyagers are in the location NASA says they are, from people who operate large radio telescopes. You said "Such a belief defies natural physics". You're basically saying "I don't understand how this works, so I don't believe it" There are 3 ways to handle such a situation. 1. learn more until you understand how this works. The best option, but it takes time. 2. Accept that you don't understand and trust the people who do understand. That's what I meant by 'accept science'. You can't be an expert on everything, so at some point you have to believe what people are telling you. This is made easier by the fact that every science is transparent: scientists publish their work, and explain how they reach their conclusions. Scientists continuously check each other's findings. A wrong conclusion doesn't survive long. 3. assume you know better than the entire scientific community. This is what you were doing. Science is built on a solid foundation where everything is tested and verified. An assumption doesn't have any foundation so it is far less reliable.
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@WSCLATER You claim that the radio link between Voyager and Earth 'goes against natural physics'. I've actually done the calculations for that link for myself, and the results I got indicate that that link does not go against natural physics. So either you're just assuming (i.e. arguing from ignorance), or you think the whole field of electromagnetism is using the wrong equations. The same physics that governs the radio link between Voyager and Earth also governs every radio link here on Earth. We have billions of those. So the science of radio is well-understood and verifiable (and has been verified billions of times). If you want to challenge that science, go ahead, but be aware of the amount of evidence you are working against. Just saying "I don't believe it" is not enough: you have to prove that our current understanding of physics of electromagnetism is wrong.
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Because everyone buys the cheapest version of whatever they need, instead of spending a bit more on a high-quality item.
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Sure, those vehicles would be reliable. They'd also cost a million dollars each.
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Welcome to the laws of physics. Nothing is free.
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bits.
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You haven't done any research, nor have you used common sense. Five minutes of searching would have told you that the blastoff was filmed by a camera on the lunar rover, which was controlled from Earth. The first steps were filmed by a camera that was installed on the LM, and which was controlled from inside the LM. None of this was deceptive or faked.
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Wifi is designed to be short range, because the shorter the range, the more wifi hotspots you can install without them interfering with each other, and the more users you can serve. Radio waves don't travel well through solid obstacles, so each wall between you and the hotspot reduces your signal. The same goes for cell phones. That doesn't mean all radio is short range. In 1901, Marconi was able to send a radio message across the Atlantic. These days, radio amateurs can contact people on the other side of the world with inexpensive equipment and the right conditions. NASA uses a giant dish to receive Voyager's signals. They use receivers cooled to near absolute zero to reduce noise, and they have a clear line of sight without obstacles between transmitter and receiver.
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Uh, we have found millions of Sun-like stars. The number of habitable-zone planets we've found is small, but rapidly increasing.
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@mbukukanyau Sun-like means G2-class stars, i.e. with very nearly the same mass and composition as the Sun. We're very good at determining what type a star is from a distance already.
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@mbukukanyau JWST is the first instrument that will be able to determine if there's life on an exoplanet, previous instruments aren't sensitive enough to do that.
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A relay won't help the Voyagers: they aren't close to getting out of radio range, they're running out of power to run the radio.
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You can receive a signal from so far away with careful design of the transmitter and receiver. Dish antennas concentrate the signal into a narrow cone, providing an enormous amount of gain over omnidirectional antennas. NASA uses a 70 m dish to receive Voyager's signals. You can also build very sensitive receivers by cooling them to cryogenic temperatures (which reduces noise). The DSN can receive signals much weaker than the Voyager's.
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The Voyagers are too small and dim for JWST. But we don't need JWST for this: we know exactly where they are. The radio link we have with Voyager allows us to measure its distance to an accuracy better than 1 meter, and its horizontal and vertical position (azimuth and elevation) down to fractions of an arcsecond.
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That's incorrect.
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@Ashghaus False. There are no bodies aboard the Voyagers. There is no space for them, and the added weight would have made the mission impossible.
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Earth is in a part of its orbit where it's moving in the same direction as the Voyagers, at a higher speed than the Voyagers.
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Voyager 1: they wanted a close look at Saturn's moon Titan, this dictated the path for the flyby. Voyager 2: They wanted a close flyby of Triton. Triton's orbit is at a large angle to the ecliptic plane, and Triton was below Neptune at the time of Voyager's flyby, so they needed a course change that pointed "down" from Neptune.
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IIRC the argument was that Voyager 1 would be the first to reach Jupiter.
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Space is empty. Really empty.
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They're traveling away from us at a huge speed (~10 km/s). The Voyagers have a small amount of fuel on board, enough for minor corrections to the trajectory, but they'd need several hundred tons of fuel to cancel out that speed and start heading back. Getting that much fuel to their position would take dozens of Starship launches.
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No. They're too dim to be seen by JWST. Radio telescopes can see the Voyagers.
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no, it's too small and dim for that.
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The Voyagers had a number of failures. Voyager 2's main transmitter is dead, and its backup transmitter has a failed component that means we can't just transmit to it the way we normally would: we have to find the frequency it's working at first before we can send commands. The Voyagers are still working because they were built to last. The best components were used, they built in as much redundancy as they could, and they avoided components that degrade as much as possible. The computers were designed to detect problems and recover from them automatically. This happens regularly. A 3 year-old iPhone has one component that 'turns to garbage': its battery has a finite number of charge cycles because the chemicals inside degrade with each cycle. The Voyagers don't use batteries. Printers are made to be disposable because manufacturers have found it's more profitable that way. Not because they can't build devices that last. My stereo system is 20 years old and still works like new. My parents have a typewriter from the 1950s that still works.
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There's no information on it on the internet. Many Voyager documents haven't been digitized, so to access them you have to travel to the archive that holds them.
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They'll stop transmitting in a few years (the team is trying to get them to 50 years, so 2027), they're running out of electric power.
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The Voyagers don't have sensors that would enable it to detect a ship nearby. So all we'd know is that the spacecraft has stopped transmitting.
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There's no point in doing that. With the receivers we have now, we could stay in contact with the Voyagers until 2057 - if the Voyagers' power supply would last that long.
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None. The trajectories of the Voyagers were chosen because they wanted to visit specific moons of Saturn (Voyager 1) and Neptune (Voyager 2). Whatever else lay along that course is coincidental.
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