Seems like this entire Pluto mission has opened up quite a few questions for Geologists. For such a small world so far from the sun, it sure has some very interesting features and characteristics. The recent mountain range photo/3D map was incredible.
We live in some exciting times. Every few months we have a new probe somewhere teaching us so much about our tiny corner of the universe.
"If NASA's New Horizons mission to Pluto is extended beyond 2017, the entire active human presence at the outer planets will consist of a single probe the size of a grand piano"
The last time the NASA budget was this low as a percentage of the federal budget was 1961. It's really bad that this isn't well understood on a site like HN. If we can't justify it here...
I imagine many of the most expensive years were due to the space race with Russia. Basically, a side-effect of the cold war. Can that really be taken to represent the peak of human interest for the sake of science alone?
Why is a percentage a relevant measurement here? I think you would just want to measure budget compared YoY adjusted for inflation. The reason it doesn't make sense is that the US budget doesn't need to be balanced. It's not like spending a ton more on subsidies for something new (e.g. renewables/electric cars/healthcare) means that NASA lost money).
You have managed to derail the conversation away from the science and imply that America is falling behind in space. Claiming the US should be even more dominant in space seems odd given the lopsided reality. Maybe you are invoking American exceptionalism.
I'm not sure why you're looking at space exploration as a competition where we want to dominate. It's not a competition. We should welcome everyone. Even if no one else participates we should still increase our effort, not reduce it. There's so much more to learn.
As I mentioned earlier, this article explains it much better than I could:
> I'm tired of saying this, but I have to say it again. The NASA budget is four tenths of one penny on a tax dollar. If I held up the tax dollar, and I cut horizontally into it, four tenths of one percent of it's width, it doesn't even get you into the ink. So I will not accept a statement that says, we can't afford it!
> Do you realize that the 850 billion dollar bank bailout; that sum of money is greater than the entire fifty year running budget of NASA.
> Do you realize that the 850 billion dollar bank bailout; that sum of money is greater than the entire fifty year running budget of NASA.
I'm not disagreeing with the general sentiment, but I don't like when people mis-use this example. The bank bailout was repaid in full--it was a loan. It didn't in the end cost the government anything.
Do you have some more details on this? I can't find any specific statements anywhere that it was repaid in full, nor even that it was supposed to be repaid; but then again I'm not knowledgeable about this area and could be issuing the wrong search terms.
I don't have any links to the details, but I do recall that the US government put some restrictions in place to its debitors, especially on bonuses. This gave the banks a strong incentive to pay back its loans.
That's a pretty rudimentary and tired view. Having a single super power that acts as playground bully seems to leave the world in a pretty stable state. It's hard to ignore that fact. A massive cut in the military budget could have unintended consequences of another cold war, etc.
you're right. Yet what do you want from an ape species who makes beheading videos and posts them on entertainment sites? There are huge chances that we may be at some bifurcation point before very possible fall into Dark Ages or into collapsing into a planetary-sized self-centered ant colony (which i think is among the main traps what most early technological civilizations in the Universe fall into (other trap being of course is an all out nuke war)).
ISIS and their ilk are such a small percentage of what humanity is all about. Don't look at them and think that we're moving towards a new Dark Age. Life in much of the world is as good as it has ever been.
Exciting times is a bit of a stretch. I was cutting black and white pictures from newspapers of Viking on Mars when I was a kid. 40 years later we're finally checking out Pluto.
Things will get exciting when the cost drops 100x and we're beaming back hi-def video and images 24x7 from all the planets and moons in our solar system.
Let's dream a little bigger and set the goal much higher.
This mission was launched 9 years ago. I'm surprised it even had 40GB of storage space.
Mars gets within 0.3 AU of the Earth when the orbits line up. Pluto is at best 29 AU away. That's almost 100x harder, and it's amazing it took only 40 years.
And all those other problems like getting people to Mars, or the moons of Jupiter, for example, will be easier?
All things with space are difficult, expensive, and possibly dangerous. Sure, getting to Pluto was difficult and cool, but that's the nature of space exploration.
Folks, I appreciate that you don't like melling's opinion here, I have problems with it too. But can we not create an echo chamber by downvoting it into oblivion? That's not what voting is for. Let him have his say, if you disagree, then post a response. The way to win an argument is not to bludgeon the opponent into silence.
On HN, it's completely appropriate to use downvote for disagreement (this has came up over and over again, but I doubt it's gonna change). Generally, I tried not to downvote for just disagreement, but melling's comment is pretty much the text book sample of the middlebrow dismissal, or gratuitously negative that we try to avoid.
I was not one of those who downvoted you. And on further reading of your comments, it looks like you are commenting on the political climate of our society (no one cares about space/ science etc.), rather than specific engineering ability of the probe/ the team involves.
It is a popular sentiment, and I can say that a lot of us would agree with it. But your original comment read very much like belittling the current Pluto mission, which is a different thing and very much not welcomed here. I mean, we even try not to complain too much for the 10000 JS frameworks being posted here, let alone another probe in space.
While I agree with your first paragraph, I have issues with sweeping statements as to which viewpoints are welcome here. While I, as stated, disagree with melling's opinion in this matter, he is more than welcome to have it and make it known. Just as those who don't agree, through downvote or response, are welcome to their view.
I don't agree with him there, because unpopular opinions should still be expressible. The downvote allows you to suppress opinions that you don't agree with which I don't think fits with the spirit of discourse that a good community should have. If someone says something inflammatory, suppress it. If someone says something you don't agree with, disagree with it.
Is it time we move on and form our own opinion about the use of the downvote as a community instead of always deferring by quoting pg, whilst whose values and contributions are obvious, has only posted 1 comment[1] (and no submissions[2]) since his last active day 475 days ago?[3]
"IIRC we first had this conversation about a month after launch.
Downvotes have always been used to express disagreement. Or more
precisely, a negative score has: users seem not to downvote
something they disagree with if it already has a sufficiently
negative score."
Out of curiosity, do you consider it acceptable to downvote a message for not contributing to the conversation, even if it is technically on topic? I try to follow official policies, but I confess that I often just think of voting as a general way to express my opinion of how a comment contributes to the quality of the discussion.
The bigger issue is that people with negative reactions are more likely to downvote than those willing to upvote on touchy subjects. That creates an imbalance and everyone has to be careful not to upset the hypersensitive SJWs as a result. The same human tendency accounts for the imbalance in online reviews.
My personal rule is to not downvote grey comments unless it's offensive or extremely wrong. Sometime I even upvote a comment I don't like when it's too grey.
More troubling than downvoting Melling's first comment (which is gratuitously negative and poorly worded) is the pile-on down-voting (and lack of corrective upvoting) of their other comments to this thread, most of which are reasonable points nicely made.
I feel like I downvote more than other people (and I'm happy for mods to say where I rank in the downvote league) but I don't like the pile on that you sometimes see on HN.
Either he's editing his posts, or people are going a little nuts with the downvote button. He's not belittling anything, just expressing the same impatience that many of us feel when we regard how little progress has been made in space exploration during our lifetime.
No editing. At least one person got it. Cost me a lot of karma. If you're 20 something, everything seems great. Guess we're not getting NASA's budget doubled.
Too bad "NERVA" never was developed for unmanned missions like this. Forget the little thermocouple can for electricity - give me an ENGINE, "Heinlein" style!
I was in my teens when Voyager was a thing, and I am really impressed with the volume, variety, and quality of the modern space probe fleet. (Of course I want more, like Uranus and Neptune orbiters, but between Pluto and comets and asteroids and all those things on and around Mars, 2015 is a really incredible time for space)
I think the really unfortunate aspect of the question is highlighted by the proverbial "problems here on Earth." Namely, there are still only three DSN sites, and mission planners are said to have to fight with each other for receiver time. The fact that planetary science still has to contend with Voyager-era terrestrial resources is a crying shame.
No, it takes a certain personality to want great engineering accomplishments to be routine. Because if they're not, we'll probably be trapped on this rock for several more centuries.
[UPDATE to answer without burning karma]
Someone says "We live in some exciting times." and I try to explain how exciting it could be.
Unless we actually have the "glass is only half full" discussion there's little chance of improving the situation. We have this political correctness problem where you need to always be positive.
I find it neither unhelpful nor unpleasant. It could certainly be happening faster if we could persuade politicians to expend more money on space engineering or facilitate the raising of private capital. I find your argument strangely teleological.
No, they do not. Otherwise we'd have three dozen New Horizons-class spacecraft flying throughout the solar system and Kuiper Belt by now.
Right now, there's a sizable contingent of people who are looking at the Pluto imagery and muttering to themselves, "So what? How does this affect the Kardashians?" Some of those people -- not all of them, but enough of them -- vote. All of this self-congratulatory stroking on our part just empowers them.
Absolutely true. When a co-worker saw the picture I posted on hipchat of Charon, he said "so what, looks just like our moon."
Thankfully he was chewed out by another science fan in the channel, but a sad number of people care less about this achievement than about the latest sports team win.
I should have said "(nearly) everyone reading on Hacker News wants..."
He's complaining to the choir (of sorts) while disparaging the very real progress we are making because it isn't as good as it could have possibly been if reality were different.
The numerical accuracy and calculations needed for getting the spacecraft so close to Pluto must be pretty awesome. Does anyone know what the precision is on calculations like these?
Also, anyone know why the spacecraft has to do a flyby, as opposed to, say, going into orbit around Pluto? Is it because the fuel involved in slowing down the spacecraft would be forbiddingly heavy?
Nobody is quite answering your question about going into orbit. A simple hohmann transfer would be able to get into orbit without expending very much fuel at all at Pluto. This talk of it going too fast to slow down is specifically because they didn't do a hohmann transfer.
Pluto is really far away, and the way a hohmann transfer works, the craft ends up moving very slow relative to the destination when it gets there. I haven't done the math myself but read it would take somewhere around 35 years to do it. But the thing is, it could have been done without being very expensive. That is, unless the nuclear generator doesn't last long enough. And nobody wanted to wait 35 years so instead they got going really fast and got an additional boost from Jupiter.
So the real answer is, they're going too fast because they wanted to get there in "only" a decade.
Yes, basically slowing down enough to orbit Pluto would have required too much extra launch weight, although the difference isn't enormous. The best candidate, a nuclear-electric propulsion system, would have approximately doubled the spacecraft's mass. This Stack Exchange question has more information: http://space.stackexchange.com/questions/9851/requirements-t...
Additionally, from the linked paper [1], it would have required a 15 year transfer phase and a more capable launcher than the Atlas V.
The report proposed using a then-unavailable Ariane 5 variant, which would have delayed the launch to 2016 (to line up the gravity assist with Jupiter) and put the final encounter with Pluto at June 2033.
So basically, if we can build a new probe within the next year and a half, and if this new Arianne variant is now available, we might have a chance of sending an orbiter to reach Pluto by 2033? That sounds like an opportunity that's too good to pass up if we can pull it off.
I mean, the flyby's awesome, and it's bound to give us all sorts of new insights on the formation of the Solar System, but having a permanent orbiter there would let us continually study Pluto (and its moons), giving us that degree of information on a continuous basis.
>if we can build a new probe within the next year and a half
The amount of cost and level of precision and robustness required tends to mean that these probes take years to plan, design, build, and test. It's also far from clear that the value of the science of sending an orbiter to Pluto would outweigh other potential missions (that also wouldn't have the same timing constraints.)
Sure, though it sounds like the ESA's been planning such a probe for quite some time already. The linked report even has specifics on instrumentation payload and the mass thereof, and includes a rendering and parts list for the proposed "POP" probe. We'd just need to do the "build" and "test" parts, and while that likely would normally take a couple years, I reckon we could cram that into a year and a half with enough effort.
Looks like a great proposal, but I don't see the point of preparing such a mission before we get all the data back from New Horizons. Once we have the latest data, then we'll have a much better idea about the kinds of questions that we would like an orbiter probe to answer. Already even with just about 2% of the NH data back, it turns out Pluto is radically different than most planetary scientists predicted. On the basis of the full data set, we'll have a much better idea of the types of instruments we'd need an orbiter to have in order to help solve these mysteries. So while the linked paper is a very useful proof of concept for an orbiter mission, and was in no way a waste of effort, actually building and committing to it and a launch in 2016 would have been a mistake.
> The numerical accuracy and calculations needed for getting the spacecraft so close to Pluto must be pretty awesome.
You can actually get by with relatively mediocre precision since the craft can be remotely piloted and its trajectory adjusted as needed. NASA was sending corrections to New Horizons just hours before its periapsis to Pluto.
It would be very different if we launched a satellite and then couldn't alter its trajectory in any way (and it would probably impossible to get it to do anything interesting since even the presence of just three bodies can lead to a chaotic system).
Source on that? Even the Tajectory Correction Maneuvers (TCMs) are planned in advance, and it's just the details of the TCM that are finalized in the lead-up to those events.
As far as the final approach goes, the core sequence started July 7[1], and no adjustments were made to it. They even had a TCM opportunity before that in case of a possible collision, that I heard was skipped.
Good question about the precision; we only hear little snippets about hitting virtual windows in space within 100km or so. New Horizons is running a MIPS-1 R3000 processor[0], that has double-precision floating point available but presumably fixed-point arithmetic could be more suitable here. But I don't know that there would be so much accumulated error, there were a few course corrections between Earth and Pluto. Maybe the precision is not so much of an issue?
As for the fly-by, well. Speed is a problem. At the point of closest approach to Pluto it was going at 13.78 km/s, and it's about the mass of a grand piano[1] so that's about 45TJ of kinetic energy. Or some large number anyway. Let's just carry on with Newtonian stuff and assume the numbers get worse if you do it properly. At current speed its orbital radius[2] would be about ... 4600 metres. Three miles!
That's somewhere deep within the icy core, I'm guessing.
In order to orbit at the distance of the photos we're getting now, it would need to slow right down to 264m/s, shedding basically all of that kinetic energy. Back of the envelope numbers suggest that would require about the equivalent of a 90 megaton explosion! Of course, if we strapped the Tsar Bomba[3] onto New Horizons, there would be more mass, so we'd need more stopping power ... and so on.
Other reasons for doing a flyby, I suspect, is that we get to see more stuff this way. There are a few moons, and an uncharted Kuiper Belt. Seems a shame to come all this way and only see the one thing. Not to mention the allure of the tantalising glimpse ... always leave them wanting more! This mission started with Pluto being nothing but a blurry dot occupying a dozen pixels. Imagine what the next mission can do, based on what we're already learning! Iterate and improve.
I assume the spacecraft carried navigation sensors to let it control its route in a closed loop. That's how you can go however far you want without requiring unbounded precision in your initial calculations.
> See the "Guidance and Control" and "Communications" section of the NH
> Spacecraft Systems page for a detailed answer.
>
> The short version is that it uses a combination of star trackers and IMUs
> (Inertial Measurement Units). The star trackers analyze pictures of the
> surrounding star field to determine how it is pointing instantaneously, and
> the IMUs track how it is rotating in between each of those instants. This
> determines the attitude (which way it is pointing).
>
> For position determination, "ranging" tones are sent from the earth and
> echoed back by the craft. This combined with the angle that the dish is
> pointing at to get the strongest signal tells the operators where the craft
> is in space. This information is fed back to the craft, which has an on-
> board physics simulation, and predicts where it will be until the next
> ranging event.
>
> Now, you might have noticed that I didn't mention Pluto once. That is
> because this system (minus the exact details) is used by pretty much every
> spacecraft, from those around Earth, to New Horizons, and beyond.
>it would need to slow right down to 264m/s, shedding basically all of that kinetic energy. Back of the envelope numbers suggest that would require about the equivalent of a 90 megaton explosion!
seems like you're several orders of magnitude off. Delta-v of 14km/s for a piano would require on the order of 90 tons of fuel. Delivering of those 90 tons to Pluto (ie. delta-v of 14km/s for 90 tons - that's 9000 tons, still far from Tzar bomba, though close to Fat Man/ Little Boy)
Yes. To get there in less than ten years, it had to be low mass, since a high mass spacecraft would require a launch vehicle we don't have. Since it is low mass, it can't take enough fuel to slow down. Thus, a flyby. Getting the Cassini spacecraft into orbit around Saturn was quite a feat. Pluto is even harder.
> Is it because the fuel involved in slowing down the spacecraft would be forbiddingly heavy?
Yep. It was traveling about 31,000 miles an hour relative to Pluto when it flew by. You'd have to decelerate to about 3,000 miles an hour to get under Pluto's escape velocity - that's a lot of speed to bleed off.
So did the scientists. In fact, the lack of craters is really suprising because it suggests that Pluto is still active, which would require a hot core. Unlike other bodies it the solar system we have observed, we cannot attribute this to tidal forces, as none of Pluto's moons are big enough [1], which means there is a currently unknown mechanism powering Pluto.
[1] And even if the big one, Charon, was, it is tidally locked in Pluto-stationary orbit.
> Could Pluto have an unusually large amount of radioactive elements in its core
I heard Real Scientists mention that as a possibility. We didn't expect much radioactive material out there, but we also have very little real knowledge.
I can't be the only one hoping Pluto is shaped by Plutonium?
> Could it have recently collided with a large KBO
I like that idea. I guess a planet that is mainly ice could absorb that without showing obvious scars.
> Could it have been subjected to large tidal forces relatively recently
I think it has to have been a moon of Neptune for that to have any major effect. Don't know if that's at all feasible.
If anybody else has the problem that the first and last word of each line is cropped, just disable the ".after-body, .article-body" css. This brings back the scroll bars.
In addition to the low-bandwidth pointed out by other commenters, the burden on NASA's Deep Space Network a significant limiting factor [1].
The DSN is the only system of antennas capable of communicating with New Horizons at its current distance, and shares the responsibility of communicating with many other deep space missions.
So, aside from having a bandwidth on the order of 1 kb/s, New Horizons is also going to have to wait in a queue of other missions waiting to use the DSN.
If NASA approves additional funding for NH next year, it will be flying by another Kuiper belt object in a few years. It looks like either 2014 MU69 or 2014 PN70.
They are gathering a lot of data but their transmission speeds back to Earth are very slow. They are also including a lot of redundancy in their transmission from what I understand, since there is a several year window to transmit so they might as well use it.
Adding to that, it will take time to develop models that can explain these unexpected features! Even with all the data in hand, it may take a number of years of intense study and perhaps simulation to make a convincing case for any single explanation.
It’s their way of implying that this mission will provide enough data to lead to interesting discoveries for years to come. Data on its own is useless, someone actually has to look at it and interpret it and pick out what’s interesting and what’s not and all that.
Obviously in this forum everyone jumps to the technical explanation (slow data transmissions!) but that is exactly not it.
For one thing the data is sent back very slowly. Estimates are that it will take New Horizons roughly 16 months to send it all back.
Then you have to sort through and analyze it and use it to verify predictions formulate new hypotheses and so on. The data will still be impacting scientific progress for years after we get it all and sort through it.
Craters, or lack thereof. They assume some rate of impacts, validate against other parts of the surface, other planets, and Chiron. No craters, the surface has been remodeled too recently for impacts to mark it.
Not all of the ice is water ice. Some is methane ice, carbon monoxide ice, etc. That being said, I've definitely heard members of the New Horizons team speculating about water ice being responsible for some of the mountains they've seen and even the idea of Pluto having an internal ocean at some point.
One of the big problems with Pluto is that we would not expect it to still be active. One of the hypothesis that has been proposed is that the heat from Pluto's formation is trapped in an internal ocean and is slowly being released as the ocean freezes.
Of course, even if this isn't what is powering Pluto, the other mechanism might still make the core hot enough for liquid water.
Water is plentiful in our solar system. Much of it is locked up as ice, but it appears there is lots of it in liquid form underneath the ice in several moons as well.
We live in some exciting times. Every few months we have a new probe somewhere teaching us so much about our tiny corner of the universe.