This is one of my favorite reasonably recent Voyager anecdote, from a recent special about the program.
Paraphrasing, the person said "You carry more computing power in your pocket than what we have on Voyager. And by that, I don't mean your smart phone. I mean you car key fob."
The voyager probes had 450 watt of total electrical power at launch, supplied by 3 RTGs. The plutonium alone in one of those RTG units (4.5kg) would easily cost $10M.
And it's the type of thing that is only used by government programs, very dangerous to handle, and which requires a whole specialized industry to produce. The accounting gets complicated. I wouldn't be surprised by a $100M cost per RTG unit.
Interesting related tidbit - Most sophisticated computers would instantly fail when exposed to outerspace. The process of making them rad tolerant is expensive and complicated. Using simpler chips makes it easier and means there is less that can go wrong. This is why most space bound computers even today appear on the surface spec sheet to be out of date.
That was popular understanding until Spacex used normal intel chips for most of their flight hardware. They have the computers generally in triplicate do a bit flip in one doesn’t cause issues, and it is many times more cost effective.
That’s ... probably correct on the facts, but won’t a key fob be using something along the line of an ATtiny or an STM8S0? Those have pretty decent computing power as far as historical microcomputers go (about a TRS-80 or an Apple ][ or a somewhat downscaled AGC) and may even be clocked at 12 or 16 MHz, yet routinely have absolutely pitiful amounts of RAM (to be distinguished from program ROM), down to 256 bytes in some cases. An 8-bitter with 2 or 4K of memory and one with 64K of memory afford very different programming styles and environmental conveniences.
And that exact anecdote is contained in the article.
> In fact, the smartphone comparison is not quite right. “The Voyager computers have less memory than the key fob that opens your car door,” Spilker says.
A better way to phrase this would be "Look what they managed with only 70 kilobytes of memory. Now what have you done with all the terabytes you have available to you?"
I've got to say that I am very doubtful of that. A key fob just generates one time passcodes, and offers the ability to set the seed to be used. I've implemented this sort of algorithm on SIMs (to be used for VPN authentication, not mobile authentication). You don't need 69kB for that. Even 1kB would be luxurious. So why would a car key fob have more than the 69kB on Voyager computers?
Yeah, probably a bit of hyperbole :) I'm no auto guy, but this seems to be an example of a microcontroller used for key fobs: https://www.microchip.com/en-us/product/ATA5700
- 8-bit AVR core
- 32 KB flash
- 2 KB EEPROM
The datasheet mentions SRAM, but no indication how much, and no indication of clock speed AFAICT.
I'm not knowledgable enough to know how to utilize this data in an interesting way, but I assume this "Ephemeris" data can be utilized to determine where to point your telescope for any given object.
Horizons is also available as a web interface (as another commenter mentioned), and if the orbital elements output (which is what you have there and is basically this data: https://en.wikipedia.org/wiki/Orbital_elements) is a bit opaque, you can also request it in Cartesian coordinates ("Vector table" under "Ephemeris type" in the web ui). Apparently it also has an email interface, which is neat.
I once did a hobby project doing 2-body orbital simulations, and was able to use this data to set up a model of the solar system, and satellites orbiting the Earth. It's quite a fun dataset!
Very interesting telnet site, thank you for sharing!
FYI, though, I think this may be looking at the wrong object ID.
It selected "31", which appears to be the entry for one of the Lagrange points. Voyager 1 and 2 appear to have negative ID numbers, "-31" and "-32".
By default, it does solar system bodies … planets and our moon … but you can direct it to other SPK files (time-based ephemeris summaries) for asteroids, other moons, and spacecraft.
I love the words from the President included on the spacecraft:
“We hope someday, having solved the problems we face, to join a community of galactic civilizations. This record represents our hope and our determination, and our good will in a vast and awesome universe.”
There's a good PBS documentary series on all the modern presidents and it's worth a watch if you haven't seen it already. The Carter episode dug into how he was technically well qualified and capable, but just did not have the connections and support of Congress at the time and that ultimately doomed his administration to failure. None of his ideas were able to get funding or support in Congress so his administration just flailed.
It may seem that way if one knows little about the cutthroat Nixon administration, but those folks played hardball. The kind that prolonged a war (Vietnam), killing multiple thousands to ensure getting elected. Watergate, etc. Naiveté in a nutshell, although will allow that "company culture" may not have been as well-known a thing at the time.
Cancel culture is dangerous, but being tolerant of some behaviours (which of course are much more specific and contextual in this case) was also his downfall
The big problem. Policy is super interesting and fun and touches on so many diverse and stimulating areas. Politics though is awful and puts sociopaths at an advantage.
If you're in US Congress, your vote is incredibly valuable. Yet we want our representatives to vote for what is best for our nation. These two objectives are in obvious conflict. This conflict doesn't trouble me (it has always been so) but rather the loss of awareness that this conflict exists and must constantly be mitigated is what troubles me. Congress is now full of people who are overtly self-interested, and their constituents love it. This is evidence of a major structural breakdown of American society, and it's not clear what caused it or what might heal it.
There's a good argument to be made about the 1970 Legislative Reorganization Act as being one of the first places to look. Up until then, Congress voted on a secret ballot, and the congressional votes were not made public - so lobbying had a much higher hurdle to clear (since the lobbyists could not guarantee a return on their investment by verifying that the Congressperson kept their end of the bargain).
> Politics though is awful and puts sociopaths at an advantage.
That's what the sociopaths want you to think. Look at the most successful people politically, who got the most done - Lincoln, FDR, MLK, etc. They weren't sociopaths. The recent sociopath at the top of the ticket underperformed their own party.
Is it one side of the aisle that hates Carter? Because from what I've seen/read from the outside (Canada) looking in, I saw nothing but praise for his humility and humanity. I saw conflicting opinions on what he did or didn't do during his tenure, but only positive with regards to his person and character.
Well, he DID face a 1980 primary challenge from Edward Kennedy, and barely won his own party's re-nomination with 51.1% of the popular vote as a sitting President. He was pretty well eviscerated by both the left and right a decade or two back, when he published a book labeling Israel's policy toward Palestine as "apartheid".
Speaking as a left-leaning resident of Georgia, it seems obvious to me that Jimmy Carter is not all that well-loved by his own political party:
* Part of this is because he made the mistake of bringing his own people when he went to Washington, instead of populating his administration with more federal insiders.
* Part of it is because he lost, and no one likes a loser (I'd say that Carter's place in the Democratic Part is similar to that of George H.W. Bush, without the legacy of an heir going on to serve two terms).
* And I believe that part of it is because, on the heels of the Civil Rights Act and the re-alignment it ushered in, Democrats were never all that genuinely enthusiastic about having a white Southern leader. It took 12 years of futility for them to embrace Bill Clinton (see point above, about how people more fondly remember Presidents who win re-election). And even Clinton's legacy has picked up a lot of tarnish over the past decade.
Yes. Even to this day, high praise for Nixon and Reagan; and nothing but utter contempt for Carter. More telling of the people laying the condemnation than of the man himself.
Not sure. I was raised by conservatives (albeit somewhat middle of the road) and they and most conservatives I’ve chatted with really admire Carter as a person; just thought he was an incompetent president.
My childhood church group (all Republicans, I’d guess) used to build houses with Habitat. It’s kinda hard to think poorly of Carter when he built something that does so much good.
I wonder if the loud, vitriolic right wingers make it seem like the right thinks as a united, extreme block, when maybe there’s a large, quiet group that is not well represented? Not sure. I may also just be in a bubble of reasonable centrists. My left wing and right wing friends are pretty centrist in my estimation.
> maybe there’s a large, quiet group that is not well represented
Often referred to as the "silent majority".
> My left wing and right wing friends are pretty centrist in my estimation.
I think this is many (?most?) people's experience, whilst media (social/traditional) are geared towards demonizing both "sides", to increase engagement. I say "sides", because most people's opinions skew left/right depending on the issue in question, rather than fitting perfectly into the stereotypical archetypes.
> I wonder if the loud, vitriolic right wingers make it seem like the right thinks as a united, extreme block, when maybe there’s a large, quiet group that is not well represented?
They are all voting for Trump and the Trumpists. How moderate are they?
The folks I know were mixed on that. Some held their nose and voted for him, some voted independent, and some went Democrat the last go round. I went independent.
Not to dismiss your experiences, but we are talking about the claimed "large quiet group". It doesn't seem so large if Republicans are strongly supporting Trump and Trumpists.
I'm not really sure, but I do remember my parents *hated* Carter. I remember distinctly sometime in the '90s thinking "Look at all the amazing things Carter has done with himself after being president. I always thought he was an asshole!"
Crediting him with bringing about desegregation is giving him a bit much. He merely stopped pissing down the leg of his secret service detail long enough to sense which way the wind was already blowing.
Your point made, however: it takes a true monster to survive American politics.
An example of why Carter was a terrible President. Remember the looong gas lines? I sure do. For years, just getting gas was a miserable experience with arbitrarily long waits, up to hours.
Reagan's first act was to sign an Executive Order eliminating all oil and gas price and allocation controls.
The gas lines vanished literally overnight (and I'm not exaggerating) and never returned. Boy do I remember that.
Carter could have done that. But he simply didn't understand economics.
Sadly, Biden is considering having the government control fuel distribution again.
It was during the Nixon administration that price controls and rationing of gasoline were introduced, in response to the OPEC oil shock of 1973 (crude oil prices had been set by government since 1971). You mention Reagan's executive order, but that was just closing the stable door after the horse had bolted; Carter began the phaseout of the Nixon-era price controls in 1979.
"The President [Carter] said that he would set gasoline consumption targets for each state and would order mandatory steps, assuming Congress allows him to do so, if the states fail to save as much gasoline as they are supposed to do. One such step, he added, might be the weekend closing of service stations."
Carter dinked around for 4 years failing to get it done, and Reagan does it in a few minutes with the stroke of a pen.
All your article shows is Carter simply didn't understand the problem. Reagan did.
Not mentioned is the DOE also controlled allocation of gasoline to filling stations. That was quite a disaster. Reagan ended all that nonsense with the same EO.
Isn't it interesting that Biden is going down the same path? He'll fail just like Carter.
You placed all the blame for gas lines and price controls on Carter, when it was a policy imposed by Nixon and continued by Ford. Then you complain about Carter 'dinking around' because he opted to work with Congress and stick to the goal of trying to balance the federal budget. Many of the price controls had been dismantled by the time Reagan took office.
I might observe that Carter's 'dinking around' also reduced the federal government's budget deficit, which increased sharply under the Reagan & Bush administrations, along with the national debt.
The 79 oil crisis and rationing was caused by the disruption of oil from the Iran, but the US suffered much more from the disruption of the oil from Iran than other countries that also relied on this oil. It would be wrong to ignore the role the government played in making this oil disruption significantly worse.
From "TheU.S. Petroleum Crisis of 1979", PHILIP K. VERLEGER, JR.
>...On February 28, 1979, DOE published the following notice in the Federal Register: "It is essential that refiners enter the spring driving season with adequate gasoline stocks to meet seasonal demand requirements. We recognize that gasoline stocks are currently at adequate levels for this time of year, which is usually a period of low demand. Recent industry data indicate that total stocks are now in excess of 265 million barrels, which is less than last year's record high levels during the same period but above the average levels of previous years. Our concern is that these stocks not be drawn down precipitously as soon as the impacts of the Iranian shortfall are felt by refiners. Refiners are urged to keep stocks high enough to meet expected demand during the 1979 summer driving season, even if it is necessary to restrict somewhat the amount of surplus gasoline that is made available to purchasers currently"
The implementation of these instructions had the effect of restricting the volume of gasoline available to service stations to between 80 and 90 percent of 1978 levels. This reduction was greater than the reduction in total gasoline supplies.
>...In April 1979, DOE ordered the fifteen largest refiners to sell 7.8 million barrels of crude oil to smaller firms that were unable to obtain supplies on the world market at competitive prices. …These transfers probably reduced the volume of gasoline produced in the second quarter because the refineries that purchased the crude oil had only a limited capacity to produce gasoline, while the refineries that sold it could have produced more. ...In addition to reducing the supply of gasoline, the buy/sell program appears to have affected the geographic distribution of crude oil and gasoline. This is because the primary recipients of the crude oil were refineries in the Midwest and the gulf coast areas, while the sellers were companies that were marketing throughout the nation.
>...…In April, DOE turned its attention to the low stock of distillate fuel oil … Two impacts were observed on domestic markets. First, excessive stocks of heating oil were accumulated. Second, companies may have been influenced to increase gasoline stocks in anticipation of the mandator yield controls that DOE threatened to impose. These controls specified the percent of refiner output that had to be heating oil. Such controls were designed to curtail the output of gasoline. By building higher gasoline inventories, refiners could smooth out the month-to-month distribution of gasoline despite the controls.
>...Price controls on gasoline may have also created an incentive to withhold gasoline from the market when the prices of crude oil were rising rapidly. …In summary, the refiners had the capacity and the knowledge to take advantage of this opportunity. Ironically, the instructions from DOE to the companies were to do precisely what was most profitable.
>...In addition to encouraging the buildup of stocks, DOE may have added to the shortages by creating an incentive to reduce the output of crude oil. Although it is difficult to estimate what domestic supplies of crude oil might have been in the absence of any restriction, a DOE announcement in November that control levels of the base period were to be reviewed may have constrained production in the first half of 1979.
Nobody ever seems to remember that the DOE also allocated gas to gas stations on a per-station basis. This was complete madness, as it did so based on the previous year's usage patterns. Of course, patterns never repeat themselves very accurately, and the result was gluts in Florida and shortages on the left coast.
A gas station had to apply to the DOE to get gas, and write a paper justifying this. I know this because a friend bought a gas station. He couldn't get a DOE allocation because the gas station across the street filed an objection with the DOE that no gas was needed for the new owner. So his gas station sat with no gas for 6 months or so.
That's Carter's energy policy. Well meaning, but completely wrong.
Without going full conspiracy, is there any chance this was a pre Koch brothers example of industry undermining government authority until it gets the government it wants?
I’m trying to square how only [15% of oil price controls](https://www.nytimes.com/1981/01/29/us/president-abolishes-la...) remained when Reagan single handedly saved the day. Seems like Carter spent 4 years doing the hard work and Reagan was able to capitalize on the last bit, which as the article states, Carter would have accomplished by spring.
Genuinely amazing human sure, but terrible President. He didn’t get anything done and nearly lost the nomination from his own party for a second term, which is rare.
> “We hope someday, having solved the problems we face, to join a community of galactic civilizations. This record represents our hope and our determination, and our good will in a vast and awesome universe.”
This is a lovely saying, but it feels like fairly strong false advertising. "We hope X", interpreted literally, implies that people physically engage in such forms of thinking. I do not believe this is actually true at ground level, rather, I think this is more of a story that we like to tell ourselves about ourselves.
> Plenty of us do. The fact that we're not running the world is a detail.
I think that "we're not running the world" was the GP's point. It _is_ an important detail in the context of the President saying these words, to remember that he is not one of us who do really engage in this type of thinking.
SpaceX's own mission statement doesn't mention becoming part of a community of civilisations [1]. It mentions making humans multiplanetary, but that is a very different aim [2]. Further, it's a good idea to be skeptical of corporate mission statements generally.
SpaceX is doing exciting stuff in the field of rocketry; that's really happening and it's worth being excited about, but they aren't doing more. It's misguided and dangerous to treat them as utopian idealists.
Criminy, aren't they doing great? I finally found a way to buy some shares of SpaceX. I don't even care if that investment does badly, I just want to share in a tiny bit of SpaceX.
> dangerous
?? On the scale of things that terrify me, SpaceX doesn't move the needle.
On a portion of it - I don't see any attention paid to discovering how to teach human beings how to be better at good will, which is part of the claim.
This is a good overview of the Voyager program, but did they just slap that headline on it to try and make it news? I was expecting some sort of announcement. But there isn't even any definite plans to shut down any instruments in the near future.
The Voyager crafts generate a never ending supply of news articles about leaving the solar system or shutting down, because there plenty of different moments that are considered "leaving the solar system" or shutting down, and there are multiple Voyager crafts as well...
What is astonishing is how little these space crafts have travelled. They go at 38k mph and it would have still taken them 40,000 years to reach nearest star to the earth! The fastest space craft so far is Parker Solar Probe which was about 10X faster but even that would have taken 4000 years to get to nearest star. There are huge problems increasing speed beyond this because even a tiny particle can seriously damage the space craft at higher speed. The expanse of space is truly mind blowing. If physical requires that for a body to move from point X to Y it must travel through all points in-between then we are screwed.
> But if an engineer had a choice to put in a part that was 10 percent more expensive but wasn't something that was needed for a four-year mission, they just went ahead and did that. And they wouldn't necessarily tell management.
Engineers doing good things even though everyone else doesnt want to care & just wants something cheap. Heartbreaking long tale of humanity, that opting to do good things is so hard to get buy in on.
When Frank Lloyd Wright's famous Falling Water home was being built, the contractor realized Wright had too little reinforcing rod in the section of the house cantilevered over the creek, so added more against Wright's orders.
Otherwise a structural failure would likely have happened.
Considering how the Pyramid were likely planned as an eternal afterlife home for the Pharaoh, I would have though the answer would be more along the line of 'Of course! I'll go and beat a few peasants for the necessary money'
I was on the receiving end of numerous support cases caused by what has to be on the sub-dollar cent savings (per single sku) region when multiple mainboard manufacturers chose to use capacitors with slightly worse tolerances all of a sudden (~25 years ago).
So if the whole process of spec'ing and validating the quality of sourced materials was within their action space, ofc they'd choose (potential) fault-tolerance over price, as it was mission critical.
So there might be a reason why we refer to it today as space race and not race to the bottom.
> not understanding and following requirements isn't something
engineers should be doing IMO
I disagree, engineers are not robots. Good engineers may second guess
and get technically involved in adjusting badly written instructions
or mangled schematics, and do so all the time. And no, the "process"
for querying and changing requirements is not always practical. Of
course good engineers should document and report all deviations from
the recspec and talk to the quality manager. Spotting that a capacitor
or diode voltage is under-rated and swapping the part number, no
problem. Upgrading a part if it makes no other difference seems okay
too. I've been very grateful to fab or pick and place engineers who
corrected a silly mistake I made instead of just sending me back a
board that obviously wouldn't work. But those kind of people who take
initiatives are rare to find these days,
Understanding requirements so well that you give the customer what they actually do want, even though they don't yet know they want it, sounds like really great engineering.
There is balance in all things. Engineers shouldn't be ignored, but we are also not omniscient.
As an engineer myself, having worked on product and having been a client of engineers working on products for me, I can tell you that engineers that think they have an inside track on what the client "really" wants are often wrong. The feeling is similar to that false confidence you get in any field when you have learned just the absolute basics, and I have felt it myself. That's why you don't just go and spend 10% of the clients budget without talking to them first. If clients are saying they don't want a feature, it's quite probable that the person you're dealing with actually knows what they want, and what they want is not what you've come up with.
A lot of projects that filter their way through HN die because the engineers are solving the problem for themselves and not talking to users. That is also the pattern you see with a lot of "what I wish I had known when I started my project" posts on here. Avoiding a conversation with the client because you're afraid they won't approve the feature you want to add is not really great engineering.
Rest now sweet explorers. You've given us more knowledge than we asked for and inspired untold numbers. Even in your final dreams you give us beautiful gifts and prove to the universe that we exist.
When was the launch date? It's been out there for almost my whole
life. Maybe it will turn up in the 23rd century in female form with a
shaved head and calling herself Vega.
It's the half life of the RTG that is limiting them, right? Because they're way too far to use any kind of solar power.
Ps I always thought that record was a bit funny. I mean it's a good method of initiating communication. Just strapping it to a can of poison is kind of a mixed message. "Hey buddies we're peaceful humans, ps here's a can of instadeath" :) Though I suppose little radioactivity would be left by the time it ever reached an alien civilization.
Eh, if they can’t deal with a little shielded can of death they’re not likely to have made it to space anyway. For anyone spacefaring, it’s about as hard to deal with or unexpected as a can of gas gas in an old car.
And radiation is something that's pretty unversally poisonous (instead of biological poisons which tend to be only poisonous to certain species). I don't think there's a single species on earth to which radiation isn't deadly.
I just think the records would have been better launched on their own (and hundreds of them in different directions of potentially life-sustaining systems). That'd have been cool (even though it's still a total long shot).
It seems pretty implausible to me that a species has managed to bridge interstellar space (pretty much required to run across the probe before the RTG has decayed to harmlessness) and has no idea that plutonium (or whatever their name is for it) or radiation is harmful. Hell, they’d be getting harmful cosmic ray doses without some kind of shielding even worse than they’d likely get from the RTG unless they cracked it open to feast on the chewy pellets inside.
Almost all RTGs use Pu-238 which is an alpha emitter. It is so active it gets red hot from its own energy. The reason they use it is that alpha radiation consists of relatively large particles which are easy to capture and thus take advantage of their energy. Also, gamma radiation would probably interfere with instruments and it's super hard to block in a lightweight spacecraft.
But it's not safe. Get a dust particle in your lungs where there is no protection from alpha particles (unlike the skin, which would at its worst develop easily-detectable skin cancer), and you'll die a slow and painful death. Not what I'd consider safe. Not instadeath either like I said, I know..
Sure, but it sounded like you meant while not instadeath, it'll be eventua-death.
I.e. the Simpsons view of plutonium, which is likely what's in most people's minds.
Anyone encountering the probe will pretty much by definition be very advanced, to not only get to space but also intercept something going above their star's escape velocity.
You'd expect them to wear gloves and stuff.
Plutonium may not even be the most hazardous thing on there. They may be deadly allergic to gold. (though yes plutonium is the one thing on there we can pretty much guarantee is hazardous while existing in fairly large quantities)
But who knows, maybe their equivalent of eyes get the equivalent of cancer from alpha radiation.
Although by the time it reaches any aliens the plutonium is going to be all spent. Half life of 87.7 years. After only a thousand years all that's left is 0.037%.
That's of course the thing about radioactivity: The more dangerous it is, the shorter a time it's dangerous. If Voyager were heading towards proxima centauri then it'd take 73 million years to get there.
Lots of it is already gone:
"As of June 17, 2022, Voyager 1 has 70.19% of the plutonium-238 that it had at launch. By 2050, it will have 56.5% left, far too little to keep it functional".
After 73 million years it'll be 5.1e250573 times less. It was about 37.7kg at launch. If I calculate right then the last pu-238 atom decays after only about 7500 years or so.
It's much less dangerous now than when it left earth, which is of course exactly why it's powering down.
tl;dr: By the time they find it there may not even be a single plutonium atom left undecayed.
I remember when Voyager was swinging past Jupiter for the first time. Caltech set up monitors all over campus, where we got to see the pictures as they arrived. We'd check the monitors before class, after class, etc. A popular joke was if one of the moon pictures showed a giant Death-Star-like hatch on it, how fast we'd be putting together a manned mission to investigate.
It was fun watching the scientists boiling over with excitement when all their theories were trashed by each new picture, and they had to reinvent them from scratch.
Notice that today you can download all the raw data sent by the voyagers and create your own mosaics and false color composites (each image was taken with a separate multispectral filter). This is a very beautiful and inspiring project for tech students.
If I could decide, I would happily scrap all human missions and launch one massive science robot with a huge visible light camera on it per year. Idlewords convinced me of this:
Great article. Learned something new. The satellites were larger than I thought.
Coincidentally, randomly the other day, I thought how much more advanced our computing would be today as a species if we worked within the constraints of the computing of available at the time of Voyager or even the 90s.
I think we would favor information and communication vs. cruft and entertainment. Working within constrained computing environments forces us to make tough decisions about what is important or pushes us to innovate and be creative with what we have to work with.
Our 'computing' is many orders magnitude more 'advanced' than what was available at the time. There's no technology that's advanced faster in the history of technology, a completely unprecedented rate of innovation even in the industrial era. It would be very odd indeed if it somehow became more advanced by not advancing it.
Carl Sagan is mentioned in the article. He was quite a treasure. He came by our dorm once for conversation and dinner. The conversation was about whether life could be based on silicon rather than oxygen. I.e. living rocks! Very fun.
1. The last human to touch the spacecraft was a physicist inspecting two detectors — probably part of the low-energy telescope system (LET).
Although many scientists have worked on the Voyagers over the decades, Cummings can make a unique claim. “I was the last person to touch the spacecraft before they launched,” he says. Cummings was responsible for two detectors designed to measure the flux of electrons and other charged particles when the Voyagers encountered the giant planets. Particles would pass through a small “window” in each detector that consisted of aluminum foil just three microns thick. Cummings worried that technicians working on the spacecraft might have accidentally dented or poked holes in the windows. “So they needed to be inspected right before launch,” he says. “Indeed, I found that one of them was a little bit loose.”
2. Carl Sagan not only commented on the “Pale Blue Dot” but also persuaded NASA to take the photograph in the first place.
Sagan urged NASA officials to have Voyager 1 transmit one last series of images. So, on Valentine's Day in 1990, the probe aimed its cameras back toward the inner solar system and took 60 final shots. The most haunting of them all, made famous by Sagan as the “Pale Blue Dot,” captured Earth from a distance of 3.8 billion miles. It remains the most distant portrait of our planet ever taken. Veiled by wan sunlight that reflected off the camera's optics, Earth is barely visible in the image. It doesn't occupy even a full pixel.
Sagan, who died in 1996, “worked really hard to convince NASA that it was worth looking back at ourselves,” Spilker says, “and seeing just how tiny that pale blue dot was.”
I find the space-age to be super fascinating! The Venera program is one favourite, where they managed to put a lander on Venus more than 50 years ago and send back data.
Just imagine the skills and knowledge with the technology at the time, to figure out how to land something safely in an unknown environment. Love it!
Curious that you refer to the "space age" in the past tense. Though it might be because the enthusiasm for humans traveling between planets and stars has been somewhat tempered since the 1960's-1980's.
I mean, we say industrial age as in past tense even though we have more industry than ever.
We are doing more space launches than ever right now, it just doesn't define this time. The birth of the internet and rise of computing technology sent us into the information age.
If Voyager had the equivalent of a modern cell phone, worth of compute. What would have been the power requirements for the mission for the same duration?
I am terrifically saddened by the fate of Scientific American. That magazine was formative to me in my teens; now I won't even bother browsing a copy left in the breakroom.
The only other magazine that I miss as much is old-school Byte.
I would add Nat Geo to that list, given one has an interest in our planet, peoples, culture. I had subscriptions to these given to me as a kid and enjoyed reading every one of them. It was like a part time general education course that I really did not appreciate until roughly a decade after it was all over.
Space navigation is amazing. If I throw a rock into the lake I can barely see where it is until it hits the water. When we fling these craft into the void how do we know where they are and where they are going?
I can think of three ways:
(1) get the direction right in the first place and just assume the craft is where we calculate it should be;
(2) watch it from afar somehow; or
(3) have it tell us where it is.
These seem like three quite different options and I would love to know how it’s actually done.
Votager 1 hasn't changed its trajectory much since 1980, so just modeling its trajectory from there would be fairly accurate.
However, they also calculate range precisely by sending it pings and timing its response. They calculate velocity precisely by looking at the Doppler shift of that return signal (https://geekswipe.net/technology/aerospace/how-nasa-calculat...). Measuring those over time provide a fairly precise location.
Thanks for engaging! Do the pings return a location, or are these range and velocity (and orientation from onboard sensors?) values used for dead reckoning, with Earth as the starting point?
When external forces impart a force on the craft (eg exciting new moons!) how is that taken into account?
I've read about determining the "state vector" on the Apollo missions, and I would imagine it's similar for voyager. The ping delay and Doppler shift should be enough to determine 3D position and velocity with respect to some coordinate sysem. I know JPL ( and/or perhaps other agencies like ESA) have a computer model of the solar system where you can run a spacecraft's trajectory forward through time. It can also account for gravitational anomalies if the distance to a planet/moon is close enough where it matters. Assuming they have gravitational anomalies modeled for that body. I'm pretty sure at least Jupiter has a decent anomaly map. In voyagers case, using the sun as a point mass, combined with its state vector at any known time, any undergrad student who knows the vis viva equation can determine voyager's position at any time.
The problem with getting a gravity assist from Jupiter is that it causes Jupiter to slightly slow down. Now, you might imagine that Jupiter is very big, and the slowdown is infinitesimal. But these things add up, and as more and more craft get a boost from Jupiter, Jupiter will lose orbital velocity and spiral inward to get sucked into the sun.
If Jupiter starts going significantly downwards by the time when it'll be just a fem million years until Sun goes supernova, we (whoever that will be) will have to hurry and flee anyway. It it involves crashing Jupiter into the Sun, and likely wreaking complete havoc in the inner planets' orbits, so be it; the system will become unusable anyway.
But until starfaring is developed enough, we should be careful with any gigaton-scale spacecraft doing gravity assists!
> if the models were correct, should have pushed the heliopause farther out than 120 AU. “It was unexpected by all the theorists,” Krimigis says. “I think the modeling, in terms of the findings of the Voyagers, has been found wanting.”
Uncalibrated and/or unfalsifiable computer models should never be trusted.
45 years in space. About time for another set of probes to go beyond where they went and explore the border of the solar wind with more modern instruments.
The full quote with context makes it pretty clear that the author is talking about crossing into interstellar space/leaving the solar system. It certainly could have been better worded though and should be fixed.
“And they have crossed into interstellar space, according to our best understanding of the boundary between the sun's sphere of influence and the rest of the galaxy. They are the first human-made objects to do so, a distinction they will hold for at least another few decades.”
It doesn’t matter what it’s about though - if they were first at something then barring time travel they will always be the first, no matter how many more do it.
"according to our best understanding of the boundary" -- they are the first to cross the boundary unless our understanding of the boundary changes, and then there is the small possibility that something faster can reach the "real" boundary faster.
The way I see this is: today, we say that Voyager 1 and 2 were the first.
Imagine that Voyager 3 and 4 are launched next year.
In 100 years from now, people will say that voyager 1,2,3 and 4 were the first.
It's not that voyager 1 and 2 will lose that distinction, but they might share it with others, in the same way that Voyager 2 shares it with Voyager 1 to our eyes.
> They have traveled farther and lasted longer than any other spacecraft in history. And they have crossed into interstellar space, according to our best understanding of the boundary between the sun's sphere of influence and the rest of the galaxy. They are the first human-made objects to do so, a distinction they will hold for at least another few decades.
They will be the ones that have traveled the farthest until faster objects catch up and surpass them. It may take time until we send anything faster, and it's going to need time to catch up, so it will take decades.
But that’s not what first means! You’re either first or you have traveled farther, combining them into one clause doesn’t make sense.
If I’m the first person to be the fastest runner, then nobody else can be first. It just doesn’t make any sense. Someone can be faster, but they’ll never be first.
> Flandro calculated that the repeated gravity assists, as they are called, would cut the flight time between Earth and Neptune from 30 years to 12. There was just one catch: the alignment happened only once every 176 years. To reach the planets while the lineup lasted, a spacecraft would have to be launched by the mid-1970s.
How many of such startling discoveries get noticed by bureaucracy/administration nowadays? Back then, it seems ideas percolated to execution stage pretty fast. I wonder if a part-time working grad student's serendipitous finds will be taken seriously to action in today's environment.
That’s called an “opinion piece”, it is editorial content. Scientific American is a popular science publication. Most people read it for the scientific journalism, not for the opinion pieces.
Editorial content is always going to be hit or miss.
I randomly searched the magazine's archives and found lots of articles on society, culture, and history in any year I looked. Any narrative that the magazine used to restrict itself to natural sciences and engineering seems false to me.
1906 snow sculptures; "money of savages"
1918 reorganization of a government health department
1929 construction in Washington and the role of the US Congress
Your, and GP's, comments gave me the impression that you thought humanities weren't touched by SciAm until recently. I think I proved that narrative wrong. It wasn't my narrative.
It is not generally possible and or ethical to apply the scientific method to these topics to arrive at greater understanding.
People who understand science also understand the method is the basis for science. It's a simple thing, and when applied yields understanding. Understanding isn't knowing in some absolute sense either. It's in the predictive sense. We do A and get B. Degrees of confidence, and scope of applicability are relevant here too.
Old understanding is as valid today as it was upon realization, for example. It's that we understand more and or the outcome of that greater understanding puts the scope necessary to get things done, or improve on our body of understanding, well outside what older understanding can do for us. General Relativity works well, until it doesn't, in which case we must use Special Relativity, for example.
The basic problems we've got with these two areas of interest is an inability to roll back the clock and repeat experiments. Secondly, people are unique entities, unlike atoms and other things we encounter and want to study, and given we are discussing people here, subjecting them to experiments has numerous ethical and legal concerns.
What we can do is work with the data we do get as an artifact of the people and their agency as well as the machinery of society and apply rational, and people who are experienced in these areas would argue inferential thinking as well as deductive type thinking, post fact and arrive at something like understanding[1], but the nature of all that means confidence is low, repeatability for all but supremely exceptional circumstances, and most definitely not on any sort of demand, is off the table.
Add all that up, and it's not really science in the basic sense applying the scientific method can add to our body of scientific understanding.[0] It can't be! We are denied the use of the method!
[0] Ideally, our body of scientific understanding is all rooted in the scientific method. What we get from our study of these two won't be rooted in the scientific method.
[1] This is not to say these areas of study have no value! They absolutely do have value. Please do not take my argument here as anything other than an attempt to clarify why they are not science.
> comparisons of programming languages either take the form of religious wars or undergraduate textbooks so determinedly neutral that they're really works of anthropology.
If the founder of this forum really believes sociology and anthropology aren’t sciences, then respectfully, he is categorically and unequivocally wrong.
Paraphrasing, the person said "You carry more computing power in your pocket than what we have on Voyager. And by that, I don't mean your smart phone. I mean you car key fob."