Hacker News Reader

Comment by Sharlin | Hacker News Reader

That’s a really pessimistic take. Voyager 1 moves at ~17 km/s (and slowing down but it doesn’t really matter). That’s on the order of 0.0001 c and indeed just a half of Earth’s orbital speed, so a part of the year the probe is actually getting closer in Earth’s frame.

A one-kg nanoprobe attaining 0.001 c would be perfectly feasible with today’s tech and would overtake Voyager 1 within a decade. Breakthrough Starshot proposes laser sail acceleration of gram-scale probes to > 0.1 c, a thousand times faster than V1, and nothing in the design requires fundamentally new tech. Such probes would claim the distance record in a few weeks of travel, no matter whether they’re launched twenty or fifty or a hundred years from now.

View on HN

I don't see a date announced for launch, and I see a lot of technology that needs to be invented for this to be feasible. How likely is it to happen within the next 10 years?

I'm just thinking about my old roommate, a space science postdoc, who told me about all these cool propulsion projects that sounded very feasible. That was—sheesh—20 years ago, and I keep waiting for any of them to be real.

It's just a question of funding. There's nothing that's needed to accelerate small enough probe on an escape trajectory at a few hundred km/s except plain old chemical rockets with enough stages. If we can accelerate a >500 kg probe to 20 km/s, we can certainly use an extra stage with 400 kg of propellant to boost a 1 kg probe to much higher velocities.

And nobody talked about the next ten years. The GP said "fifty years", which is way too long a time span to have any certainty whatsoever as to what will happen. GP's assertion was 100% ludicrously overconfident.

Just a note: I responded directly to a comment that said it could be built with today's tech, let alone 10, 20, or 50 years.

Ah, yes, it was my own comment :D Sorry for the confusion. What I meant was that bog-standard chemical rockets work just fine for ~100 km/s if the payload mass is low enough and you use enough stages.

But note that "within a decade" I meant "within a decade from launch".

What scientific return are we getting from a gram sized probe moving at 30,000 km per second?

Today: almost certainly nothing In a decade: almost certainly very little In a century: almost certainly more than the Voyager

Assuming climate change doesn't prevent any kind of launch or most further research.

Wouldn’t the reduction in atmospheric density due to warming make it easier to reach orbit, etc?

Yes but widespread flooding, drought, crop failures and economic collapses etc. would make it much harder to devote resources towards such launches.

Modern silicon design with mems sensors I suspect could do an awful lot with a gram.

Also, at this scale, not much can be done by hand, so you can make hundreds of them for not much more cost than doing one.

Doesn't modern electronics require massive shielding?

e.g. you would need too much shielding and would go over the 1 gram restriction.

If you have enough of them you can just lose some fraction and still function.

Also it may work out that a lighter, faster probe with a shorter service life could have a greater effective range, if the service life is less sensitive to weight changes than the speed is

Right, that’s a nice way of thinking about it.

And how do you get the data back from these probes? The voyagers have antennas that are close to 4 meters in diameter and ~25-watt radio transmitters. You aren't doing that in a gram, and you aren't powering that in a gram either.

Just go read the starshot proposal. They address all of these issues, some more convincingly than others but they have thought it out in great detail.

In short, it’s a swarm of gram-scale probes and they work together to transmit.

The claim was that it would always be the furthest man made object in the universe. Nothing about it being useful or scientific.

If its not useful, it's not going to be launched and accelerated that long.

People do things for shits and giggles all the time. SpaceX literally launched a model Tesla for absolutely no reason other than advertising both themselves and their sister company.

Doubly so if they can now become “the furthest man made object”. That’s massive free marketing.

It may also be exponentially easier to do so in the future, lowering the expenditure needed to make it happen.

It might not be reasonable right now, but, once again, the bar was set at always. That is an exceptionally high bar with very little reasoning behind it.

They absolutely had way more of a reason than no reason. Za reason for the Tesla launch was that it was the first falcon 9 heavy launch, and no company was willing to gamble that large of a payload on a untested rocket. So they made the best of it with a PR stunt.

They literally could have sent up anything and it certainly wasn’t useful, which was GP’s only criteria for being launched.

>scientific return

that comes after 'someone out there' misinterprets our super fast gram probes as weaponry and conquers our world for the sake of their own spacecraft safety.

it's ingenious really, let's antagonize a greater power into wormhole-bridge hopping over here so we can reverse engineer their tech.

/s , hopefully.

If they are so much as inconvenienced by our probes, they are not a greater power but bumbling roboticists like us.

1 gram at an appreciable amount of c is about as much energy as a nuke. Getting hit by a swarm of these while on a Sunday drive would fuck you up, no matter how powerful you are.

The real reason there isn’t a moon colony? Person gets fired and loses their shit, starts tossing 1-2 km sized rocks down the gravity well and … we all die.

Throwing shit in space is a sure fire way to piss off any species.

It would take an insane amount of energy to throw that rock.

But you only need one. Maybe two for good measure

Same with a nuke or an engineered pathogen. Throwing rocks from the Moon is less practical though, people would see you setting up the universe's biggest launch pad or railgun for years. It would be the least stealthy, most telegraphed apocalypse possible.

It only takes a 50-meter (radius) rock to destroy a city, a 240-meter rock to destroy an entire region, and a 4 km rock to destroy the planet.

So, I guess it depends on what you want to accomplish, whether they see it coming or not.

"Only". Those are huge! Especially when you consider the city you have to build around them to launch the damn things.

The required delta-v isn't all that much from the moon, and it's more about the mass and speed than the actual shape of the rock.

To throw a 100 meter rock that would wipe out NY city (and then some), we could do that with modern technology... assuming the rocket never had to slow down.

If you have enough of them, you get data from Alpha Centauri within a human (natural) lifetime. Plus the bragging rights, I guess, Starshot is after all a private endeavour.

Reply on news.ycombinator.com