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NASA selects a plan to "swarm" Proxima Centauri with tiny probes

140 points| Brajeshwar | 2 years ago |sciencealert.com | reply

133 comments

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[+] gumby|2 years ago|reply
dang, could you fix the title? This isn't NASA's plan, it's a collaboration between Space Initiatives and the Initiative for Interstellar Studies.

The article's title is 'NASA Selects a Wild Plan to "Swarm" Proxima Centauri With Thousands of Tiny Probes'

[+] jessriedel|2 years ago|reply
This happens constantly. Some random scientist at one of NASA's dozen's of labs write a speculative proposal, and all the news articles say "NASA plans to do X".
[+] dang|2 years ago|reply
What's a more accurate and neutral title?
[+] cwillu|2 years ago|reply
Kinda true, but the article did say “The concept was recently selected for Phase I development as part of this year's NASA Innovative Advanced Concepts (NIAC) program.”
[+] snakeyjake|2 years ago|reply
Breakthrough Starshot is a scam and I can't believe that NASA is falling for it.

1. Extremely high duty cycle 100 gigawatt laser. (edit: now apparently it's an "array" because someone with a brain mentioned that a 100 gigawatt laser is ludicrous) That's right 7 peak summer output Grand Coulee Dams and 12 Palo Verde nuclear power plants with all reactors operating simultaneously COMBINED would be needed to power this laser.

2. "Swarm" (jfc buzzwords) craft that are currently impossible to create. The swarm behavior including networking, sensors, radio, and command and control do not exist and are impossible at a simple base level when considering RF energy requirements even with far-future theoretical energy harvesting technology.

3. Perfectly-spherical-frictionless-cow-ifying the EXTREMELY REAL effects of space weather. Forget the interstellar medium, these things will be blown out of the beamwidth by the time they reach jupiter's orbit from solar winds alone.

[+] jessriedel|2 years ago|reply
> 1. Extremely high duty cycle 100 gigawatt laser. (edit: now apparently it's an "array" because someone with a brain mentioned that a 100 gigawatt laser is ludicrous) That's right 7 peak summer output Grand Coulee Dams and 12 Palo Verde nuclear power plants with all reactors operating simultaneously COMBINED would be needed to power this laser.

That's not how this stuff works. You would use some sort of large capacitor/battery bank which is charged by a much smaller power draw over a long time, and then dump the energy over a short time.

The laser array currently operating at the National Ignition Facility has a peak output of 500 TW, more than three orders of magnitude higher than the number you called ludicrous. Obviously Starshot would be applying that power for a much longer time interval, and indeed would be a global undertaking dwarfing NIF. But it doesn't need 100GW of dedicated power plants.

[+] gumby|2 years ago|reply
> Breakthrough Starshot is a scam and I can't believe that NASA is falling for it.

I know some of the folks involved and they are working on 50 years to launch. It's a long term (multiprong) research project.

I wouldn't call it a scam, I would call it "blue sky" (if it weren't a space project!)

[+] chuckadams|2 years ago|reply
It's one of many competing research projects, the sum total of which add up to less than a single shuttle launch. I'm content with a dead end or two.
[+] dylan604|2 years ago|reply
You announce this kind of project so Congress Critters can get all up in arms about wasteful spending and is something that can then later be sacrificed to make them feel like they've done their job. Meanwhile...you have other projects that have been protected from the axe because the sacrifices of this farcical project.
[+] lxe|2 years ago|reply
Given 1.6 sq meter 500W solar panels, that's an area of 320 square kilometers. That can be constructed at $1/w at $100 billion.

Also it's not necessary (or technically, it's actually impossible) to have 100% duly cycle laser for propulsion.

It's definitely a megaproject, but it's not a "scam"

[+] hex4def6|2 years ago|reply
I'm curious about whether it's even feasible based on dispersion issues. My understanding is that it's hard to beat dispersion over long distances, regardless of your optics on the laser (and we're talking long distances here...)

Any optics experts able to chime in?

[+] p1mrx|2 years ago|reply
100 GW isn't absurd, compared to global human energy consumption of around 20000 GW.

The problem is, until we figure out how to stop burning fossil fuels and fix climate change, the amount of spare power we have is actually a large negative number.

[+] nynx|2 years ago|reply
The power is so high so that the probes can be accelerated up to 20% of the speed of light while still in the solar system. The array does not run for long periods of time.
[+] paulhart|2 years ago|reply
Good typo in the article:

“the energy source for a lightsail is photos (which have no mass and move at the speed of light).”

So, it can be powered by memes?

[+] seized|2 years ago|reply
Only by memes of cats with buttered toast attached to their backs.
[+] m3kw9|2 years ago|reply
This is the one time they are forcing the issue when the tech isn’t even close but instead throwing 100billion to make it happen. Maybe use half that to do research for better fuel, materials, miniaturization and the other 50 to launch with higher chance of success
[+] dtgriscom|2 years ago|reply
This idea has shown up multiple times. I've never understood how they plan to communicate back, especially with a) gram-scale devices b) moving a significant fraction of the speed of light away from us while being c) multiple light-years away.
[+] mjrpes|2 years ago|reply
This article attempts to explain: https://www.nasa.gov/general/swarming-proxima-centauri/

"A swarm whose members are in known spatial positions relative to each other, having state-of-the-art microminiaturized clocks to keep synchrony, can utilize its entire population to communicate with Earth, periodically building up a single short but extremely bright contemporaneous laser pulse from all of them."

[+] gumby|2 years ago|reply
A kind of bucket brigade. They aren’t planning to launch a cloud of these things and be done, they’ll be launching a long stream of them for years.

The probes can get power from the launch laser.

At least that’s the idea I got from talking to some of these folks last year.

[+] ofslidingfeet|2 years ago|reply
Probably the plan is to have some kind of small electronic that flies there and then sends signals back.
[+] GartzenDeHaes|2 years ago|reply
Probably also worth noting that the laser would have practical military uses.
[+] andrewstuart|2 years ago|reply
The distance is so ridiculously incomprehensibly far is hard to see this as anything except science fiction fantasy.

If you think this sort of thing is possible you really don’t understand how far it is.

To put it in relative perspective, if we represent the furthest distance humans have ever traveled as 1.3cm then the nearest star is 200 kilometers away.

[+] javajosh|2 years ago|reply
Yes, but...the analogy I like to use is to imagine that we are tiny creatures living in a hole in a vast sheet of ice. Our hole is ~1 au in diameter, Proxima Centauri is 270k au away. So if the hole is 1cm wide the next hole is ~2.7km away. That's a long way for a microbe to walk, but it's not outside the realm of possbility if the ice is very, very flat and it can make tiny ice skates such that you don't need to spend energy to maintain speed.

Of course, the real problem with the analogy is that the fastest you can go 1 cm in this universe is about 8 minutes. So the absolute shortest time it takes you to travel that 2.7km is 4.2 years. That's a few hundred cm per year. But in reality the best we could possibly do is a few tens of cm per year (e.g. c/10), and even that's in the realm of science fiction.

On the bright side, humanity has the Solar system all to itself with wonderful natural barriers to invasion and conquest. So we have time to figure out how to not blow ourselves up and/or stop dismantling our life support system to make Ikea furniture.

[+] irrational|2 years ago|reply
What about the voyager probes? How far has the farthest one travelled in your analogy?
[+] 29athrowaway|2 years ago|reply
Voyager 1 (1977) travels at 38,210 mph.

The ISS (1998) travels at 17,400 mph.

There's abundant precedent of accelerating to high speeds in space, where there's no friction with an atmosphere that slows you down and where you can use gravitational fields as sling shots.

0.3c might seem high but if you keep accelerating you will eventually reach that speed.

[+] ofslidingfeet|2 years ago|reply
Since you want to take such a condescending tone about it, here we have an entire fucking article about how NASA thinks it's possible and is working on potential solutions.
[+] happytiger|2 years ago|reply
True but we haven’t been further than the moon, our nearest neighbor. Unmanned missions have gone much further with success (and even returned).
[+] jbperry|2 years ago|reply
I don't see a way to slow down. So they would be travelling thru that solar system at .2c. At that speed, they wouldn't be in that solar system for long.

Imagine this was Proxima Centauri doing the same mission on our solar system. Assuming that some of the swarm was on target enough to go thru the inner solar system:

Mars is ~13 light minutes from the sun. So double that for the whole diameter of the orbit, 26 light minutes. At .2c that's 130 minutes total transit time (less really unless it passes really close to the sun). So probably less than 2 hours total in the inner solar system. And that's assuming you can hit that small of a target from 4.25 light years away.

Light distance Sun-Saturn is 1.3 hours. 2.6 diameter. 13 hour transit time for most of the solar system.

You don't know where the planets actually are going to be, or were to point a camera or any other instrument, except the sun. And you have probes that weigh grams.

That's a tough problem, without considering the laser.

But I like thinking about it.

[+] ta93754829|2 years ago|reply
lets say we did this, and we got the tiny probes up to even ~speed of light... then what are they going to do when they get there? what sensors can they carry and report back. And we wouldn't be able to slow them down, so they're going to transit through the target solar system relatively quickly (days even).
[+] pokstad|2 years ago|reply
Just put a frozen brain in space and use nukes to send it there.
[+] readyplayernull|2 years ago|reply
Thinking whether they could use one of the projects aiming to launch small payloads into space, sort of space trebuchets:

SpinLaunch - Developing a system that spins a payload at ultra-high speeds inside a vacuum chamber, then launches it into the sky using stored rotational energy. They claim it could launch small satellites for a fraction of the cost of traditional rockets.

Launchloop - Proposed concept of using a powerful electromagnetic accelerator called a Launchloop to fling payloads into space. It would use low-cost electricity rather than expensive rocket fuel. Still in early feasibility stage.

TAES - Developing a space trebuchet mechanism that uses centrifugal force similar to how a trebuchet launches projectiles. They're aiming to launch 6U CubeSats (10x10x30cm) to Low Earth Orbit for a relatively low cost per launch.

Rocket Lab - Makes small Electron rockets for launching 150kg payloads to LEO. Over 20 successful launches to date and helping enable more frequent smallsat launches.

Virgin Orbit - Uses a modified Boeing 747 to carry a 2-stage LauncherOne rocket to altitude, then releases and ignites to place payloads in orbit. Aims for frequent, affordable smallsat launches.

[+] 14|2 years ago|reply
None of those solutions are suitable for this mission. These satellites need to be traveling a hundreds of thousand of kilometres an hour or more. Think about voyager 1 traveling at 65,000km/hr. It is still over 18,000 years before it will reach a light years distance and this mission is talking about 4 light years. So the launch really has zero importance as does getting these satellites up to massive massive speeds. Anything less then like 1million kilometres per hour is probably just too slow. Edit: even at 1 million kilometres per hour it would still take over 4000 years to reach the full distance so really we need to be going unimaginably fast to get there.
[+] kolinko|2 years ago|reply
Launching from altitude gives you very little, so does spinlaunching.

It is because it’s about speed, not altitude. Witch Spinlaunch, they plan to laumch around 5000kmph, and you need a speed of around 25000kmph to reach orbit.

In other words, they would need to use their setup to launch a rocket of a size of 1/2-3/4 of size of a falcon1 to get into orbit, and even then, unless they land the second stage, they will come out far more expensive than what SpaceX is doing.

The tech may work on moon, but even on Moon a different solution - similar to maglev - may be better, bacause there would be no issues with crazy centrifugal forces.

Anything launching from earth will require some sort of a rocket fuel (or some new laws of physics), because even if you managed to launch at the speed of 25000km/h from the ground, the payload would slow down before it left the atmosphere.

[+] temp0826|2 years ago|reply
Do these launchers actually make sense? Maybe from the moon (obviously not for earth orbit-destined satellites, but deeper space)
[+] dvirsky|2 years ago|reply
What would happen if a 1g probe traveling at 10% of the speed of light hits an inhabited planet with an atmosphere? The kinetic energy is insane, but will it just burn out in the atmosphere or will it manage to hit the surface and go boom, assuming earth like atmosphere?
[+] kibwen|2 years ago|reply
According to the calculator at https://www.calculatorsoup.com/calculators/physics/kinetic.p... , 1 gram traveling at 29,979,245.8 m/s has 449,377,589,368.41 J, or about 449 gigajoules.

According to a quick search, the asteroid that killed the dinosaurs had about 300 zettajoules of energy. 1 zettajoule is 1,000,000,000,000 gigajoules.

So it would be on the order of a trillionth as much energy as the Chicxulub impact.

[+] barbegal|2 years ago|reply
The energy is something like 100 tonnes of TNT so a big bang but not catastrophic to the planet.
[+] Jabrov|2 years ago|reply
I think it's unlikely it will impact the surface because it's so small. It also depends on the material. Temperature on entry can be thousands of degrees and most materials would just vaporize
[+] GuB-42|2 years ago|reply
It is big but not that insane. Think about it: these probes are accelerated with a 100GW laser, they are not getting more energy. So cut the middleman and shoot that 100GW laser at the planet directly.

On Earth, we get about 1kW/m2 from the sun. So 100GW is what we get from a 100km2 patch of land. So, all the energy from the system is enough to turn night into day for an area the size of a medium sized city.

Of course, it is not a continuous beam, so it would be more like an explosion. It would be nuke-sized if it wasn't for losses, but obviously, there would be losses. But the thing is, we are not destroying planets with the energies we get from a 100GW laser.

Edit: Also, at these speeds, the probe is a bunch of high energy particles causing nuclear reactions along their way, things like chemical bonds don't make much sense. There is an XKCD What-If about relativistic object hitting earth. Not the same scale, but it may give some idea of the physics involved. https://what-if.xkcd.com/20/

[+] sp332|2 years ago|reply
Let’s see, total surface area of 1 square km, 1,000 probes in the swarm, that’s 1,000 square meters per probe… but it can only weigh a few grams? Also it can’t be sparse because the point is to capture light energy instead of letting it pass through.
[+] aussieguy1234|2 years ago|reply
Could the tiny robots, at the other end, self assemble into something bigger?
[+] yencabulator|2 years ago|reply
How about step 1, you let us know when you have gram-scale computers, we can make some money on-planet and use that to fund the rest of your program.
[+] Log_out_|2 years ago|reply
The cool thing is that swarm can form a half sphere mirror halfway, slowing one probe at the center down.
[+] joe_the_user|2 years ago|reply
Is there any plan to slow the probes or would they inspect Proxima Centauri very quickly?
[+] lgkk|2 years ago|reply
I wish I could be alive when humanity’s first Dyson sphere powers up.
[+] sidlls|2 years ago|reply
This is ridiculous. Set aside the (incredibly optimistic, to be charitable) thinking that is going into the acceleration of these probes. The astronavigation itself is hugely questionable, especially with probes that aren't big enough to hold the kinds of equipment necessary to detect bodies that would perturb the trajectory, let alone make adjustments after encountering these.

I don't think people realize how mind-bogglingly, incomprehensibly HUGE space is. It's BIG. Like think of the biggest thing you can comprehend, and it's not even the size of an atom in comparison to even "short" distances in space.