[–] Isamu link

That Earth-Moon L2 halo orbit is cool, I didn't even know that was a thing.

[edit] I mean I was aware of Lagrange points, but not the practicality of the halo orbit. This is a nice explanation:

http://hyperphysics.phy-astr.gsu.edu/hbase/Mechanics/lagpt.h...

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[–] Florin_Andrei link

Yeah, it instantly makes sense if you calculate the force at the Lagrange point and notice the vector points back at the exact L point when you're in the vicinity - and then you go, hmmm, looks like it might be possible to orbit that thing.

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[–] enos link

Will L2 congestion become a problem once JWST and a few more missions join this craft? Will we have to manage that orbit like we do with geostationary?

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[–] Isamu link

An interesting point from that page:

>A full n-body dynamical system such as the Solar System does not contain these periodic orbits, but does contain quasi-periodic (i.e. bounded but not precisely repeating) orbits following Lissajous-curve trajectories. These quasi-periodic Lissajous orbits are what most of Lagrangian-point space missions have used until now. Although they are not perfectly stable, a modest effort of station keeping keeps a spacecraft in a desired Lissajous orbit for a long time.

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[–] daveslash link

https://en.wikipedia.org/wiki/Halo_orbit "Halo orbits can be thought of as resulting from an interaction between the gravitational pull of the two planetary bodies and the Coriolis and centrifugal accelerations on a spacecraft."

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[–] gardaani link

The lander plans to transmit data to Earth using a relay satellite orbiting at the Earth-Moon L2 halo orbit: http://www.planetary.org/blogs/guest-blogs/2018/0519-change-...

The relay satellite included two micro-satellites for the moon, only one of them survived: http://www.planetary.org/blogs/guest-blogs/2018/20180615-que...

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[–] nine_k link

His useful hypersonic flight may be?

With air being so dense and power-dissipating, it might be more economical to do a sub-orbital jump than to push through the atmosphere at 7M. For short-range military applications, iirc, hypersonic rockets exist.

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[–] TangoTrotFox link

Really useful.

You've gotta consider how much things change as you get higher into the atmosphere. The obvious thing is that atmospheric oxygen begins to become insufficient to operate engines as you go higher up, so you need engines that use a different oxidizer than atmospheric oxygen which is extremely complex. And even the efficiency and characteristic of engine exhaust changes radically depending on atmospheric density and the characteristics of its exhaust. In other words an engine that works great at sea level might work awfully when you start to get to a fraction of the same pressure.

There's an immense amount of flexibility in being able to travel hypersonic. The SR-71 Blackbird is an amazing example of the potential. First flown back in 1964 (!!) it was capable of hitting around mach 3, some 2200 miles per hour. That's 6 hours to get from one side of the Earth to the other. It's really quite remarkable how much our overall transportation technology seems to have stagnated since the 60s. I'd like to imagine everything is just classified but everything from the SLS to the F-35 to even things like the Zumwalt just seems to indicate that we've simply technology regressed. Kind of disconcerting to imagine the reasons for that.

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[–] nradov link

All current military hypersonic (Mach 5+) weapons are ballistic missiles. No one has demonstrated sustained hypersonic flight through the atmosphere but that's probably coming in a few years.

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[–] ohitsdom link

NASA does a lot of work on hypersonic flight. Lots of sources to link to, here's an article from a few years ago:

https://arstechnica.com/science/2016/02/meet-nasas-new-x-pla...

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[–] melling link

That’s Nasa’s quiet supersonic project.

Hypersonic is five or six times the speed of sound.

It would of course be nice to have both.

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[–] Tepix link

I'd rather see them spending it on NASA than on the military.

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[–] jniedrauer link

Ironically, these were mostly the same thing during the space race. I watched a USAF training video on re-entry mechanics[0] a while back that really drives this home in an almost dizzying context switch. It goes from the mechanics of delivering a thermonuclear payload in one sentence, to returning humans to earth in the next.

[0]: https://www.youtube.com/watch?v=c_bkY7-9c8s

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[–] tzfld link

There is no way a space race like the one during the Cold War can appear again. Nonetheless the term space race is often used by the media just because it sounds more dramatic.

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[–] melling link

It doesn’t have to be the same type. This time the military could be involved. Its budget is approaching NASA’s.

https://spacenews.com/some-fresh-tidbits-on-the-u-s-military...

The Trump Administration wants a Space Force, for example:

https://www.space.com/40942-trump-space-force-reopens-milita...

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[–] chadAnon69 link

we used to invest $3 into infrastructure and science for every $1 in entitlements spending. Now we spend $5 in entitlements for every $1 in infrastructure/science

And people wonder why the US is falling apart and technological advances have slowed down.

We're living hand to mouth instead of investing in the future. The sad thing is that many of our problems could be solved permanently via technology rather than government.

Instead of creating the automobile people are trying to make horses faster

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[–] BurningFrog link

The US is wasting trillions fighting wars in other countries.

China is wasting trillions building infrastructure in other countries.

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[–] rqs link

Wasting money on infrastructure is better than wasting on wars. The government of the U.S. need to learn better.

The problem with war is that no matter which side wins, both side will always in some way hate each other (Once war started, it will never end).

While even in the worse scenario, locals can still benefit from the infrastructure. Booming strategy is something Chinese people play very well.

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[–] reaperducer link

And people wonder why the US is falling apart and technological advances have slowed down.

I don't think anyone wonders why it's happening. They just feel powerless to change anything.

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[–] moron4hire link

Have technology advances slowed down? Or are we just not advancing in the big, exciting really of "blowing shit up"?

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[–] TeMPOraL link

We are now advancing mostly in the ability to manipulate, exploit and make miserable almost everyone, via adtech.

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[–] zipwitch link

That's an inevitable result of devoting the efforts of so many of our brightest to attracting eyeballs.

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[–] Taylor_OD link

It feels like we slowed down in the important areas. Software? Web Apps? We're doing great. Anything space related? Eh. In theory we get to claim SpaceX so I guess that counts but most people couldnt tell you what NASA's been up to recently...

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[–] mturmon link

There was that landing on Mars two weeks ago...

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[–] tehduder9 link

nice and vague

abolish government, libertarian paradise, ???, solve problems

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[–] rukittenme link

I wouldn't say "vague". He cited the differential in dollar amounts and drew a conclusion from the data presented. That sounds specific to me. I think you may have overreacted to his point. You should have debated the merits and demerits of welfare spending versus R&D investment. Instead you accused him of something he never advocated for.

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[–] duxup link

Would we fund it even then?

I would expect some nationalistic fervor that would help fund a space race would come from US conservatives.

But in the US the "conservative" side of politics seems more interested in short term tax cuts for corporations, dismantling government, and hating on immigrants, and other Americans...

I have my doubts the US would step up.

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[–] pc86 link

Accepting your blatant mischaracterization of conservative US politics as true for a moment, I think given the choice between "othering" folks in the US or a country on the other side of the world that most people know nothing about, politicians of any stripe would prefer the latter.

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[–] duxup link

"I think given the choice between "othering" folks in the US or a country on the other side of the world that most people know nothing about, politicians of any stripe would prefer the latter."

I don't know what you're trying to say.

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[–] arbitrary_name link

Show me reigning US conservatives who aren't espousing those ideals cited. Go on, I'll wait. Even the libertarian puritans like rand paul have fallen in line with the socially and economically regressive republican platform of today.

The only ones willing to stand up to the hypocrisy of Trump and actually represent conservatism have been sidelined consistently.

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[–] cauldron link

The tech gap is too big, despite media hype, don't think China can even catch up.

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[–] chillacy link

You can land on the moon with 60s technology, what basis is there for not being able to reach that?

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[–] 2trill2spill link

In space flight some of the most advanced technology even to this day was developed in the 60's and 70's. Things like NERVA[1], the NK-33[2], and the Saturn V[3], were developed back then and are still more efficient or bigger then similar technology we have today. The 60's and 70's were the golden age of spaceflight.

[1]: https://en.wikipedia.org/wiki/NERVA

[2]: https://en.wikipedia.org/wiki/NK-33

[3]: https://en.wikipedia.org/wiki/Saturn_V

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[–] melling link

So, you’re saying the world’s second largest economy, soon to be the first, can’t catch up in 10-20 years?

The US only spends $20 billion a year on NASA.

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[–] zozbot123 link

Agree. See how chinese trolls trying to spread propaganda are quick to reply to you with their blabbering and defensive talk. That's the only thing they're able to come closer to.

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[–] sctb link

If you keep breaking the guidelines we'll ban the account.

> Please don't impute astroturfing or shillage. That degrades discussion and is usually mistaken. If you're worried about it, email us and we'll look at the data.

https://news.ycombinator.com/newsguidelines.html

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[–] zozbot123 link

Ok I'll refrain myself next time. I'm hoping you monitor suspicious activities and accounts on here, including where the trails ends up, because I assure you weird things are happening. There's an unnatural tendency to favor a view as of lately.

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[–] melling link

Perhaps we’ll get another Space Race with China. At a point, the United States was spending over 4% its budget on NASA:

https://www.theguardian.com/news/datablog/2010/feb/01/nasa-b...

The money would probably be better spent on several projects (e.g. AI, hypersonic flight).

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[–] oh-kumudo link

http://www.xinhuanet.com/tech/2017-06/13/c_1121136834.htm

Seems like an experimental attempt to create a "Moon Surface Micro Ecosystem". Not sure how legit it is though.

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[–] gardaani link

According to this article, they try to build a mini biosphere: https://www.telegraph.co.uk/news/2018/04/13/china-plans-grow...

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[–] saagarjha link

Huh, interesting. I'm left wondering whether China has a Planetary Protection Officer, though of course the Moon is barren so it doesn't really matter…

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[–] jerf link

It isn't just barren. It's sterilized of any Earth life that may have happened along every month, which gets up to 250 degrees F (~120 C), and even if something survives that, there's never a window of time in which something like livable conditions obtain, because once out of the sterilizing sunlight the temperature immediately heads for a decent approximation of the average temperature of the cosmos. (Doesn't seem to quite get there, but it's cold enough that you could pour liquid nitrogen on to the ground and it would stay liquid if you held it at 1atm pressure. Dunno about vacuum.) So between the extreme thermal cycling and hard radiation, even Earth's best aren't going to get a foothold up there.

This is in contrast to places with a non-trivial atmosphere or standing liquids, which may moderate the environment enough that something could conceivably live. Something could conceivably live on Mars, something that isn't even necessarily that far from some things that live on Earth. Nothing will live on the Moon. You can fling as many gallons of the scummiest pond water you can find from any pond water on Earth on the moon, and you're not going to "contaminate" it with life.

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[–] saagarjha link

I'm sure tardigrades have fared worse and survived, at least for a little while.

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[–] OscarTheGrinch link

Throw enough bullshit at a problem and something is bound to grow...

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[–] Symmetry link

We really, really need more data on the responses of living creates to 1/8g. We've got all the 1g data. We've got a considerable amount of 0g data from ISS experiments. But we just don't know how living creatures respond to lunar or martian gravity. And knowing that will be very important for future colonization efforts.

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[–] cookingrobot link

Couldn’t we get that from a spinning satellite closer to earth?

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[–] Filligree link

Spin can indeed create (effective) gravity, but it differs due to the coriolis effect. We'd have two options: We can build a really big satellite, so as to minimize that effect -- or we could assume plants aren't sensitive to it, and hope for the best.

Needless to say, most scientists aren't fans of the second option.

Incidentally, long-term it would be possible to achieve 1g on the moon by way of a similarly huge centrifuge.

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[–] A2017U1 link

I can't grasp the centrifuge option, won't there still be two forces? It'll be more like those carnival rides than artificial gravity. A dropped ball won't fall straight "down".

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[–] Filligree link

On Moon?

The compartments would have to be tilted relative to the centrifuge, such that down becomes properly down.

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[–] mrfusion link

Another option is simply using a tether and a counterweight.

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[–] bdamm link

There are spinning experiments on the ISS.

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[–] mrtksn link

No, the satellites stay in orbit only because the net G they experience is 0.

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[–] i_am_proteus link

I believe the parent was referring to pseudogravity via rotation ('centrifugal force')-- hence the reference to a spinning satellite.

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[–] mrtksn link

And how this related to the proximity to the Earth? I think the OP meant being close to the Earth would result in a gravity due to the proximity.

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[–] isostatic link

I read it as being cheaper to get experiments there (1kg to LEO is cheaper than 1kg to soft land on the moon)

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[–] cookingrobot link

Yes, exactly what I meant. It seems a lot easier to get an experiment into orbit than onto the moon. If you connect two halves of the satellite with a long tether, you could reduce the coriolis effects, if that's really an issue.

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[–] mrtksn link

If that's the correct meaning, then O.K. My bad.

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[–] nradov link

I assume it's to provide food for the cane toads.

https://www.theonion.com/moon-now-overrun-with-cane-toads-af...

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[–] cauldron link

Don't know this time, but Chinese textbooks mentioned the radioactive space environment could cause mutations in the genes, creat new varieties.

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[–] narag link

Nice: giant worms in a world with scarce water laying in caves.

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[–] illegalsmile link

Let me know when I can buy a stillsuit and then we'll talk.

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[–] ccozan link

Teoretically you learn to build it yourself....

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[–] pavel_lishin link

I have ridden the mighty moonworm!

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[–] gus_massa link

You can do it more cheaply using a radioactive source on Earth. https://en.wikipedia.org/wiki/Mutation_breeding

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[–] saagarjha link

Is this something they are trying to study, or trying to protect against?

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[–] thelastidiot link

There are already hard at work planning for a clothing factory.

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[–] varjag link

It's traditionalist/nationalist symbolism of claiming the greatness, much like Russians hanging up Orthodox icons on ISS.

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[–] isostatic link

"hanging up"

How can you "hang" something in microgravity

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[–] taneq link

Easier than in full gravity, I imagine.

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[–] jcranmer link

Velcro, I imagine.

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[–] mikro2nd link

Duct tape.

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[–] lyrachord link

Claim what? NASA landed that point? To do biotic experiment, just a common sense.

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[–] saagarjha link

> It may also carry plant seeds and silkworm eggs, according to the official Xinhua News Agency.

Is there any scientific/experimental reason for this, or is it just a symbolic gesture?

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[–] isostatic link

First Long March 5 rocket succeeded in Nov '16. Second one failed in July '17

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[–] foobarbecue link

"Its program also suffered a rare setback last year with the dialed launch of its Long March 5 rocket."

Failed, I presume.

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[–] xrayzerone link

> They go slow but steady and focus on interesting stuff.

A trait shared with their social credit apparatus.

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[–] leojg link

I really like the Chinese approach to space exploration. They go slow but steady and focus on interesting stuff.

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[–] czbond link

When will China publish their own pictures of the satellite dish, cooling tower, and woman on the moon? <snark>

https://www.youtube.com/watch?v=ZNkmhY_ju8o

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[–] point78 link

Save these comments for reddit

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[–] stencil25 link

But that's where the Mi-Go are hiding...

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[–] ramos_arian link

Remember, It is made in china.

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[–] BurningFrog link

[Adjusts glasses]

Actually...

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[–] bigtech link

I'll see you on the dark side of the moon.

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[–] undefined link
[deleted]

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