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Comment by jacobush | Hacker News Reader

Never to be found again

Orbits decay, often at a plannable rate. Eventually it crashes back to earth and becomes an archeological relic for future explorers. I bet you could even design the sattelite to burn specatularly (in many colors) on the way down so it's more likely to be seen and sought after.

Though, it would most likely end up in the ocean since the majority of the earth's surface is covered by water.

Just put enough satellites so it's statically very likely that one will land on land. (Although I don't see the point of this project)

Orbits only really decay due to atmospheric drag. Other tiny bits of cosmic, rarified gas can slow the spacecraft on a long timescale, and solar radiation pressure can perturb an orbit (occasionally dramatically, if the Sun is unhappy), but the effect is far smaller than constant drag. If a small satellite is orbiting Earth at a high enough altitude which was calculated to consider the broader gravitational system (Earth's natural satellites, the Sun, and fainter perturbations from nearby celestial objects have to be factored in), orbit can be designed to be stable on a long, long timescale. Millions of years, or more.

The real fly in your plan's ointment would be exposure to space, which sucks a lot for electronics.

I don't think that's a, uh, "fly in my plan's ointment". I don't think the satellite needs electronics at all.

Those are called ballistic projectiles, and you cannot place one in a precise orbit. You need upper-stage guidance, admittedly just for the placement of the satellite, but you still need electronics. Though, that being said, I'm now curious how you intend to store large-scale data without any use of electronics.

Let me clarify - you don't need electronics that are effective forever. You would store the data in an analog format.

I'm struggling to think of a suitable "analog format," maybe help me out? Silicon tablets of runes? Analog is unscalable here, no matter how cheap launch systems are.

Probably something like this: https://en.wikipedia.org/wiki/Rosetta_Project

Stuff in the middle of a lot of not-stuff is fairly findable.

Particularly if it has a strong signature on radar or microwave imaging.

I was thinking in the case the civilization lost access to a lot of basic data. Then finding the magic satellite without magic radar, maybe without even knowing about the magic satellite amongst all the other satellites up there.

A billion years is a long time.

That said, a few redundant copies elsewhere wouldn't hurt.

Oh, no I love the idea of a time capsule in space. In fact, given how cheap some mylar (for detection) and silicon (for inscribing information) is, I think "we" (humanity) should put a bunch of it up there. Like they Voyager probes, but MUCH more data, and maybe in orbit around the sun. But it's not something to rely upon as backups - but very nice as a message into curious explorers of the future.

A deep cave structure on the moon, and large triangles formed into the lunarscape visible from telescope on earth pointing towards the entrance. Bonus: You'll probably spur space development technology faster than normal for any civilization that can see it.

Bury a bunch of magnets ....

Depends on your definition of 'findable', I suppose.

Flight 370 wasn't found after "the most expensive search operation in aviation history[1]" performed by a multinational effort over almost three years. There are distinctions to quibble about, sure, and there are things that could be done to make things not designed to shuttle meatbags around easier to find.

But the area comprising the middle of the not-stuff you reference is big.

[1] https://en.wikipedia.org/wiki/Malaysia_Airlines_Flight_370#S...

> There are distinctions to quibble about, sure

That's an example of stuff in the middle of a whole bunch of other stuff, not in the middle of a bunch of non-stuff. I'm not sure that it's all that similar at all, beyond as a a very general "finding stuff can be hard" example.

Oh, I may have become confused as to which part of this thread I was responding to - I thought we were talking about finding a satellite after reentry.

Oh, I imagine unplanned and reentry would likely make it very hard to locate, if not destroy the contents in the process. Decaying orbits would mean it's likely to happen, too. But I think if a civilization has the capability to reach an orbit, it's likely they have the technology to find something in orbit, or will shortly.

A better plan might be to create a structure on the moon to house it, and create giant triangles in the landscape of the moon visible through telescope that point towards it. The moon is fairly stable to my knowledge (except for meteorites, but I think that can be somewhat mitigated depending on the time frame we are talking about), and people always like looking at the moon through telescopes...

And we should make it black and rectangular shape. I suggest we call it the monolith. We might want to put a few of them around the solar system just to be safe.

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