Hayabusa2 is leaving the asteroid Ryugu and heading back to Earth | Hacker News Reader

Hayabusa2 is leaving the asteroid Ryugu and heading back to Earth

syfy.com

298 pointssohkamyung67 comments

The level of engineering behind this is such an amazing feat.

Landing a satellite on an asteroid, and then shooting it with rare minerals to cause debris to shoot off, to then be collected and later analysed by scientists here on Earth? All while in flight? And there's enough fuel to give this another crack on a _second_ asteroid?

I remember buying dinosaur and space magazines that often had collectable assets (like, each magazine collection would build an entire glow in the dark T Rex skeleton or similar, each magazine came with one bone and you had to get 20+ magazines for the entire 1:200 scale skeleton... we'd probably call this DLC now) and being absolutely amazed at what was written within.

This article brings about the exact same glee and nostalgia.

Yeah, this is the kind of mind-blowing, mesmerizing stuff that dreams are made of. Or rather, that makes people have dreams, much like the moon landing.

Being able to see the shadow of the Hayabusa2 coming closer to the surface, the dust when it fired, then moving away, is just simply.... Would be really awesome if there was a video version with interpolated frames so we'd get a smooth video. I know someone did that of one of the moon landings (the one with the sky crane iirc) and the result was simply stunning.

> This article brings about the exact same glee and nostalgia.

Phil Plait is one of my favourite science writers, and has been consistently putting out great "bad astronomy" blog posts for years (decades?). If you want more of his writing you can check out the website: http://www.badastronomy.com/index.html

Thanks for the recommendation. After spending some minutes browsing the content, I was delighted.

Syfy has hit that mark with the articles I’ve read on it recently too.

Now if only they could have someone proof read prior to publishing...

Now only if they could keep the shows that are actually worth watching.

eye balls The Expanse

Season 4 is on the way!

Now backed by Amazon

https://en.wikipedia.org/wiki/Orbis_Publishing

funny, I thought "yep, I remember the De Agostini collectible stuff in Italy, I wonder if this Orbis thing is the same". And apparently Orbis publishing is now a subsidiary of De Agostini.

It was DeAgostini in Poland as well. As a kid, I had a few T-rex bones from that myself.

And it seems so effortless! Like, “duh, of course we landed a satellite on an asteroid and blew off bits of minerals for later analysis. What, like it’s hard?” Obviously it’s incredibly difficult, but the point is that we did it. I like to think the very first humans who peered up at the heavens with rudimentary telescopes would be incredibly proud. They should be.

I know we don't live in the Apollo era, and timelines are much longer for space missions - but it's such a great time to look to the skies and imagine where we'll be within our lifetimes.

Hats off to the people that work night and day to get these widgets to their destinations, perform their jobs, and bring them home. I wish my skillset translated to these fields because I'd take a 50% paycut and ditch all my options to go into the field in a heartbeat.

You're right. The timelines are so long, I'm pretty sure more than a few exciting and really expensive space missions you will not see in your lifetime. We are at hundreds of years from real space colonies.

Invest in cryonics and be able to wake up in time.

Entrust your body to a corporation? Only once the end of normal life is nigh anyways.

Welcome to Night Vale has an interesting take on this, which is:

Why should the future care about you or your desires? To the future, you are simply a resource.

We are just entrusting our minds to Social Networks, so that's not that far from being acceptable

On the other hand, the more missions/programs start now, the more excitement there will be in the future when they're being completed. If companies and countries keep at it, it will soon be a long string of space missions in the news.

"...accelerating the probe to a meager 9.2 centimeters per second relative to the asteroid (slower than a snowflake falls on Earth), but that was enough to give it enough velocity to escape"

That is pretty insane.

Without gravity and atmosphere you can do pretty neat tricks with very little energy.

To me, the amazing thing is not how little gravity it has, but how much. I mean, if you look around on Earth, at a hill/small mountain about 3000 feet high, it's weird to think that has enough gravity you could in theory stand on the underside.

I'm going with Arthur C Clarke on this one

Any sufficiently advanced technology is indistinguishable from magic.

If we could just get these probes to be cheap enough we could conceivably mine asteroids. Then again the economics just don't make sense since we have plenty to mine on Earth already.

It doesn't make sense to bring the material back to Earth. But getting mass to Earth orbit from Earth is very expensive and if you want a big space habitat the material from an asteroid might be very useful, even if just as radiation shielding.

No, getting them smart enough to build more probes to do more work should be the goal...eons from now.

You’ve just invented Universal Paperclips.

Meh, as long as they're not designed to improve themselves, and there are strict protocols for ensuring all active units are controllable, it's not necessarily a recipe for solar system paperclipization.

Given enough units any protocol will be broken by pure chance sooner or later.

With appropriate organization and accounting, there's no reason malfunctioning units couldn't be repaired or reprocessed. It seems like that would be a sensible regulation for companies building self replicating machines.

> there's no reason malfunctioning units couldn't be repaired or reprocessed

If you have enough of them, and a long enough time scale, they might mutate in such a way to avoid being detected.

It's an important concern, but I think mitigatable - especially since we're not neccessarily talking about actual self contained replicating machines, and instead more likely automated factories producing drones - a multi step process where everything has to go right for replication, and into which safeguards can be engineered/studied. Basically, the process needs to be designed to fail due to entropy without external intervention/maintenance.

If we become advanced enough to consider building such things, we can engage in a serious investigation of the risks - for now it's just speculation.

Ah, but if they’re in space who’s doing the regulation?

https://en.wikipedia.org/wiki/Self-replicating_spacecraft#Vo...

We're talking about grams of raw dirt, not commercially interesting amounts of rare material that wouldn't be easier just to find on earth.

It would be nice enough to get them cheap enough that we could conceivably send enough to enough asteroids to determine if mining them was actually ever going to be worth it.

How much energy would it take to just, capture an asteroid and have it sat in the orbit of earth or some other consistently distant place, rather than having a mining operation on the asteroid as it zips around the solar system?

Could the latter be more economically viable than the former?

Capture might be done with gravity assists (via the moon) and aerobraking at earth, but it is still a significant amount of energy. It is probably easier to just mine deeper into the earth for raw materials.

There is an entire school of research associated with asteroid capture-and-return versus mining-in-place. I don't think it's a settled area of research, probably because we really don't know how to do at what cost either alternative.

Water or hydrocarbons are the only decent thing to mine and then move to Low Earth Orbit. The value of already being in space seems to be lost in these big dreams of many people.

If we can get a few metal asteroid to earth, prices would fall to near nothing and we could close all mines for the metals that are out there.

I understand all things are relative, but isn't the most expensive part of space travel escaping gravity to get from ground to LEO? Parking a mineral rich rock in orbit would still require lifting dump trucks up to the orbiting rock just to have them return with their loads.

Might as well plan a controlled re-entry of the rock to the surface. Drop it into the desert somewhere, then go mine it on the surface.

"Might as well plan a controlled re-entry of the rock to the surface. Drop it into the desert somewhere, then go mine it on the surface."

Any commercially-viable amount of rock dropped from orbit into the desert would probably hit with enough force to cause a second K-Pg extinction event. Even if it hit the middle of the Pacific Ocean, we'd be horribly screwed. The amount/cost of fuel needed to control the descent of any commercially-viable quantity of rock would probably outpace the mineral value itself.

You should be able to make some kind of primitive parachute. Not that makes a soft landing, but where it only crashes with moderate speed.

You do touch on a very important issue: Anyone who can move an asteroid to Earth can also extinguish at least a city at will. I foresee this business being very heavily regulated by the big military powers.

I might be wrong, but asteroids hitting earth are a problem more because of the speed than their mass? (E=m*v^2)

Asteroids usually hit earth with speeds from 16 to 32 km/sec, but if we brought it to earth it would be closer to 0.5km/sec

Any commercially-viable asteroid would need to be at least a mile in some dimension or another to have enough minable material. Let's assume 3200 Phaethon was our target - three mile wide asteroid, mass of 140 x 10^12 Kg.

I'll let you do the math, but just the 10^12 kg along should tell you that the idea is quite infeasible before you ever get to doing the actual calculation.

BTW it's easier to just do (KE) = 1/2mv^2 as your calculating formula.

> I'll let you do the math, but just the 10^12 kg along should tell you that the idea is quite infeasible before you ever get to doing the actual calculation.

Did you try the math?

10^12 J (i.e., 10^12 kg moving slowly) is a lot, but it’s not an extinction-level event. 4 x 10^12 J is 1 kiloton of TNT equivalent. A big boom, but if well placed...

How much energy are you going to expend to ensure that hundred-trillion+ kilogram rock can fall at the rate desired by the prior positor? Half a kilometer a second is supersonic speed. We get 1.3E+19 J now as the energy level we need to fight against. That's higher than a 100 megaton nuke by two orders of magnitude. Now fight against that every second! Don't forget to calculate the pull of gravity as well! There's still more numbers to pop into the equation!

We don't have the energy capacity to begin with. The rock would smash into us, and we'd die.

Nice goalposting there. My issue was only with your implication that the mass alone was enough.

Obviously impact speed matters too, that was the point.

I assume your 500m/s comes from the assumed algebra in my post, but the real issue is the gravitational potential energy as you allude to.

To get that rock from 2000km up (low earth orbit) to the surface means somehow dissipating 10^21 J -- two orders of magnitude higher still than your claim.

I like that other poster's idea of a "giant parachute". I hope it's made of 4000% heat shields.

Maybe we can cover it with wind turbines and power the entire US for a year. [0]

[0] https://en.wikipedia.org/wiki/Orders_of_magnitude_(energy)#1...

"I assume your 500m/s comes from the assumed algebra in my post"

I assume you didn't even READ my post, as the very first sentence is "How much energy are you going to expend to ensure that hundred-trillion+ kilogram rock can fall at the rate desired by the prior positor?" Key words - AT THE RATE DESIRED BY THE PRIOR POSITOR - as in the person who I was originally responding to in this thread, and not you.

Since you did not read my post and obviously didn't read theirs, I'm not entertaining yours. You lack the required information to make a useful contribution to this thread.

> Since you did not read my post and obviously didn't read theirs, I'm not entertaining yours. You lack the required information to make a useful contribution to this thread.

Apologies for misunderstanding what “the prior positor” meant (did you mean “poster”?) — but wow I have to say your angry response seems highly disproportionate to my misinterpreting a typo of yours.

As you yourself lack the required humanity or empathy to make it worth having a conversation, I guess we’re both done.

I don't show humanity to people that don't act human off the bat. You invoked the golden rule with your condescension and lack of empathy in your statements. I'm merely returning the attitude which was presented to me.

And no, I meant positor - https://www.merriam-webster.com/dictionary/positor

That's a word you should've learned around 6th grade.

> I'm merely returning the attitude which was presented to me.

An eye for an eye indeed makes the whole world blind.

Sorry to have fueled your anger.

No they won't. Even if you get as big as this one the article is talking about to be full of gold and drop it directly in backyard of a gold smelting factory it will barely make a dent in the price of gold. Plus our entire technology is based on using silver and gold for circuitry, so it will get absorbed really fast in the market. Currently we have so much of a shortage that we recycle old boards to extract the metals in them.

All of the gold that has ever been mined by humanity over the last few thousand years would fit in a cube about 21 meters per edge. So I think that actually it would make a big difference to grab something this size made out of gold.

https://www.gold.org/about-gold/gold-supply/gold-mining/how-...

I wonder what the best way to sell that would be? Maybe just slowly release it and use the asset as security on loans. That way you maintain the high price and get access to capital.

Depends on whether you keep it private.

If people know it's going to be released, it doesn't make too much of a difference exactly how long you are going to take.

(Unless you go really, really slow.)

> Even if you get as big as this one the article is talking about to be full of gold and drop it directly in backyard of a gold smelting factory it will barely make a dent in the price of gold.

I'm not so sure: The price of gold depends on an estimate of future supply. If a company can successfully mine an asteroid for 5 grams of gold in 2025, many people will be worried about a massive increase in gold supply over the next 50 or 100 years. They would then dump their existing holdings of gold and crash the price.

The trick is to drop it by several gold smelting factories, so one one gets a monopoly.

In reality, some entity will get the first metal asteroid, and have a monopoly for a while. But only a while.

I don't understand your arguments for no price drop. To me the facts are simple: Price is set by supply and demand. When supply increases by 10x or 100x, prices will fall dramatically.

Depends on the metal. For certain platinum-group metals (iridium, osmium), a single asteroid might contain several years' or decades' production. For more common metals like iron, copper, or even gold, it wouldn't make a dent in the market.

I’m always reminded of Warren Ellis’ talk “How to see the Future” when I read stuff like this. We have to strive to reduce the banality with which we view the world, and things like this go a long way.

http://www.warrenellis.com/how-to-see-the-future/

Is it me or those asteroids seem so lonely in space ? Their black skies and cold light makes them so desolate...

What about possible contamination from something on or on the asteroid?

Definitely the beginning of a sci-fi horror movie plot...

Imagine how much rain forest we could have saved with the money used to fund this program.

More wasteful space spending to satisfy the less than 1% of space geeks that are interested in this nonsense.

I am now worried that this day will looked back on later in history as the start of the alien wars.

I doubt it. We've been crashing things into comets and asteroids before this.

Like the Deep Impact mission in 2005. [1]

[1] https://en.wikipedia.org/wiki/Deep_Impact_(spacecraft)

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