NASA’s New Horizons Discovers Frozen Plains in the Heart of Pluto’s ‘Heart’
nasa.gov
nasa.gov
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.
Here's another perspective about the times:
"The dark future of American space exploration" http://www.vox.com/2015/2/23/8052365/nasa-budget-europa
Submitted to HN: https://news.ycombinator.com/item?id=9906017
"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"
https://en.m.wikipedia.org/wiki/Budget_of_NASA#/media/File:N...
As I mentioned earlier, this article explains it much better than I could:
> 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.
> How much would you pay for the universe?
[1] "We Stopped Dreaming" - Neil deGrasse Tyson - https://www.youtube.com/watch?v=CbIZU8cQWXc
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.
"TARP revenue has totaled $441.7 billion on $426.4 billion invested.[3]"
Its an uncomfortable truth, but there are a lot of better things America could be doing with its war economy.
I genuinely can't tell if you believe that or if you're being sarcastic.
US + others military intervention has left many bits of the world in a terrible state.
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.
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.
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.
" 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."
It's simply not accurate.
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.
http://www.byrnehobart.com/blog/why-are-middlebrow-dismissal...
No. It is not appropriate at all! You reply for disagreement. You do not downvote.
Downvotes are for useless messages, flamebait, off topic, things like that.
Downvote for disagreement leads to reddit and no one wants that.
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]
[0] https://news.ycombinator.com/threads?id=pg
[1] https://news.ycombinator.com/submitted?id=pg
[2] I do not know however if he reads or still votes on HN.
"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."So his position did seem to be a bit more nuanced than "downvote what you like".
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.
Don't worry someone is working on making space flight cheap. In 20 years, the drone craze will go interplanetary. Gonna fund my Kickstarter?
[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.
You're complaining because you can imagine it happening faster than it is, which is unhelpful and unpleasant. Thus, downvotes.
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.
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.
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.
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?
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.
(edited down to 35 years)
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.
[1] http://www.esa.int/gsp/ACT/doc/PRO/ACT-RPR-PRO-ISTS2004-Plut...
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.
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.)
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).
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.
[1] http://www.spaceflight101.com/new-horizons-encounter-timelin...
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.
[0] http://blog.imgtec.com/mips-processors/mips-goes-to-pluto [1] https://what-if.xkcd.com/137/ [2] http://www.physicsclassroom.com/class/circles/Lesson-4/Mathe... [3] http://nuclearweaponarchive.org/Russia/TsarBomba.html
> 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.
[1] https://www.reddit.com/r/space/comments/3cz66a/new_horizons_...
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)
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.
I expected just another dusty cratered rock.
[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, despite its low density overall?
Could it have recently collided with a large KBO, melting much of the surface even though the core is long dead?
Could it have been subjected to large tidal forces relatively recently, e.g. it was much closer to Neptune until a few hundred million years ago?
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.
why will it take years?
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.
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.
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.
If the surface is 100 million years or less, the number of craters makes sense.
Or we could have some other basic assumption wrong. Science has only known about this since this morning...
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.
Hydrogen is the most common element in the universe. Oxygen is the third most common.