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Blockchain offers a way of keeping track of information such that its authenticity can be verified and it can not easily be falsified.

In a space environment with an increasing number of both active satellites and space junk, as well as an increasing number of people and expensive assets, knowing where everything is and which way it's moving and how fast, as well as how up-to-date and reliable each bit of information is, and ways to ensure nobody messes with your database, will be increasingly important.

I am sure there are other ways that blockchain could be perceived as helpful in spaceflight, but this was the only one I could think of.

It seems to me that an ephemeris of space objects, verified with blockchain, will likely become "a thing".

How will would blockchain (likely) be integrated into spaceflight? Have any methods been proposed yet? Any tests done like for example with public TLEs?


See for example TechCrunch's I’m very sorry, but you’re going to have to learn to love the blockchain

enter image description here

Slim Pickens in Dr. Strangelove, or how I learned to stop worrying and Love the Bomb. Source

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    $\begingroup$ Blockchain’s only real purpose is to draw investment dollars from credulous VCs. For any task other than wasting vast amounts of energy separating fools from their money, other technologies do the job much more efficiently. $\endgroup$ – Russell Borogove Oct 9 '18 at 14:08
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    $\begingroup$ @RussellBorogove I think in this case, you may be quite wrong, but you may be right also. It will take years to find out. There's certainly a hype associated with the technology, that happens. But the underlying blockchain method may turn out to be useful. The only way this might not be the case is if something different comes along quickly that's even better. If you'd like to post an answer asserting what you've said in comments, and stand by it, that would be great! $\endgroup$ – uhoh Oct 9 '18 at 14:16
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    $\begingroup$ Relevant: i.redd.it/sx8jqorpxkzz.jpg $\endgroup$ – Tristan Oct 9 '18 at 14:27
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    $\begingroup$ As a note to all who downvoted, just because it's a "dumb idea" doesn't mean it was a bad or invalid question... Just keep that in mind when slinging negative votes. This was one of the most interesting question I've seen recently. $\endgroup$ – Magic Octopus Urn Oct 9 '18 at 16:40
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    $\begingroup$ Classical example of reverse engineering: find a problem to your solution $\endgroup$ – Everyday Astronaut Mar 16 at 21:00
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I am not going to argue or offer opinions about the merit of applying block-chain technology to aerospace, but NASA is offering money if you can come up with a way of doing it.

The 2019 NASA SBIR grants include a proposal for Blockchain as applied to aerospace Focus Area 23 T11.03. There are two areas specifically targeted for blockchain.

The first one is for large projects. The basic premise is that large projects like the space shuttle (for example) require the use of Model Based Systems Engineering to keep track of thousands of people across multiple organizations making millions of decisions. If blockchain could be used to create some sort of immutable version control system of the design that would be cool.

The second area is more of a etherum version of blockchain. The idea is to schedule ground station use based on smart contracts like in etherum.

If you want to see the SBIR proposal: make sure to open focus area 23 all the way or download the short PDF here, which begins:

Blockchain solutions can benefit all NASA Mission Directorates and functional organizations. NASA activities could be dramatically more efficient and lower risk through Blockchain support of more automated creation, execution, and completion verification of important agreements, such as international, supply chain, or data use.

A Blockchain is a decentralized, online record keeping system, or ledger, maintained by a network of computers that verify and record transactions using established cryptographic techniques. A Blockchain is a data structure that makes it possible to create a consistent, digital ledger of data and share it among a network of independent parties. Blockchain distributed ledger technology may become a key enabler of digital transformation, enabling peer to peer transactions without requiring intermediaries or pre-established trust. Blockchain was originally developed to support digital currency transactions. Now, application of Blockchain is being explored for other financial services, software security, Internet of Things, parts tracking (supply chain), asset management, smart contracts, identify verification, and much more.

NASA is seeking innovative solutions involving Blockchain that would greatly enhance operational efficiency by providing a single, immutable "source of truth", viewable by all authorized parties, and usable by automated reporting and verification systems. In Phase I, expectations are to document a concept study for a Blockchain- based solution to one of the NASA challenges described. This must include a clear explanation of the benefits of a Blockchain solution over alternative solutions. In Phase II, the goal is to deliver a prototype system. In this call, NASA is seeking Blockchain-based solutions for only the following two NASA-specific challenges:

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  • $\begingroup$ Thanks for the reminder to expand #23! Speaking of SBIR's have there been any that might apply to How are airborne particulates monitored on the ISS? Are they distinguished at all by size and/or type? $\endgroup$ – uhoh Mar 16 at 3:30
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    $\begingroup$ I don't know of any off the top of my head on that one. $\endgroup$ – Knudsen Number Mar 16 at 3:38
  • $\begingroup$ +1 for most on-topic answer. But this is not contributing to NASA's credibility. The first problem formulation suggests it's own solution, namely an "immutable version control system". Where's the problem with that? $\endgroup$ – Everyday Astronaut Mar 16 at 21:09
  • $\begingroup$ Immutable version control system, not immutable version $\endgroup$ – Knudsen Number Mar 16 at 22:38
  • $\begingroup$ Also please read the SBIR proposal rather than my interpretation if it. I don't want to be the source of misinformation. $\endgroup$ – Knudsen Number Mar 16 at 22:47
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Blockchain is a very poor solution to a specific problem: achieving ledger consensus among a large number of agents when there is substantial incentive to corrupt the record, and the entries in the ledger are directly related to one another.

This is not a good fit to a satellite ephemeris. A relatively small number of agents add records to the system at a fairly low rate, the records are independent of one another, and no one involved in launching or tracking satellites has an incentive to corrupt the record.

To protect against accidental or malicious corruption of a satellite ephemeris database, a simple SHA-2 or SHA-3 hash works. There's no need for anything more complex.

Anyone proposing blockchain as part of an ephemeris system is chasing buzzwords without considering the technical needs of the system.

Even the US Department of Homeland Security seems to understand how rarely blockchain is the right solution to a problem:

enter image description here

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    $\begingroup$ I've never chased buzzwords without considering the technical needs. $\endgroup$ – uhoh Oct 9 '18 at 15:08
  • $\begingroup$ I see, so if something like these guys or some other constellation were hypothetically self-managing their orbits and they were measuring their positions off of each other via delay time of nearest-neighbor radio or optical signals, then there might (or might not) be some kind of ledger management-like activity. But since things are more centralized, it doesn't fit. $\endgroup$ – uhoh Oct 9 '18 at 15:18
  • $\begingroup$ Ephemeris should be seen as a spring-board to other potential applications. I assume uhoh just used ephemeris as the base-line idea for what a block-chain could be used for. Maybe a block-chain for star-tracking, where computers themselves are the source of invalidly inserted data. I'd say keep an open mind regardless. $\endgroup$ – Magic Octopus Urn Oct 9 '18 at 15:19
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    $\begingroup$ Oh you caught me, I’m so ashamed of the time I launched a Downrange Distance startup because all the techies were suddenly excited about downrange distance technology. $\endgroup$ – Russell Borogove Oct 9 '18 at 15:33
  • $\begingroup$ Oh my god who gives the advice to use email and spreadsheets as a storage medium?! No! Bad! I like the diagram, but that is bad. You'll end up with shadow-IT MSAccess databases within 2 months. Should've basically suggested encrypted database for all NO points, to be honest. $\endgroup$ – Magic Octopus Urn Oct 10 '18 at 17:03
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In space bandwidth is a premium commodity. The blockchain technology treats bandwidth worse than dirt. EVERYONE receives a complete copy of the entire blockchain whether they need it or not - and satellites are only rarely in contact with each other. They are in contact with ground stations and these stations are expensive to operate.

You're not gonna engage the DSN facilities with their 20-meter deep space antennas just to synchronize every single satellite to your blockchain, pushing all the data about the entire network whether the satellite will ever use it or not. Blockchain is strictly bound to a peer-to-peer network, and DSN is quintessentially centralized.

Data exchange with satellites can be managed through public-key cryptography, and the facilities that allow for communication are rare and few enough that you don't need to worry about random hackers connecting from the ground to the satellites directly. Risk of hacking the DSN still exists, but it's both well protected, and - as I said, its bandwidth is a precious commodity and so it's closely monitored - there are live people who read and use it, so if anything 'rogue' was to be sneaked in, they'd see it.


That said, the blockchain technology, with a correctly defined 'value' function (certainly not a meaningless dump of cryptography) may have a chance to work with autonomous swarms of probes. A probe which, for example, finds 'most interesting' set of readouts may dictate the swarm to perform given operation - e.g start scanning given area. The probes are designed to remain in constant contact, and they don't need to hold the entire blockchain, just the most recent part - there's no danger of adversary parties interfering; they are out of reasonably real-time contact with Earth and allowed to operate autonomously.

This is still only something that's tossed as loose ideas and projects between scientists - no actual swarm mission proposals are under consideration. And for LEO swarms (e.g. cubesats) the satellites don't need the autonomy, decision making of which satellite 'rules the swarm' - simply because they are controlled from the ground in real-time and ground systems can make these decisions. And while the swarm can spread the command on a peer-to-peer basis, it doesn't need blockchain for that.

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  • $\begingroup$ I'm thinking of LEO where the constellations of satellites and space junk is. Invoking deep space is a non sequitur. Everyone's building these LEO constellations specifically to put a nontrivially-sized chunk of the internet's bandwidth in space. $\endgroup$ – uhoh Oct 9 '18 at 14:54
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    $\begingroup$ @uhoh: What would blockchain in that case provide? It's a technology to single out a 'dedicated leader' and maintain a complete record of the state of the network distributed throughout. You don't need to 'elect' a leader; the ground can do this just fine. Each member of the swarm doesn't need to keep the entire history and entire swarm, just the neighborhood. Peer-to-peer exchange, routing and transmission are still possible with no need for blockchain - and its massive bandwidth overhead. $\endgroup$ – SF. Oct 9 '18 at 15:01
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    $\begingroup$ The worst part is that an adversarial party could manage to engineer the 'proof of work' (like the 51% attack) and hijack the entire network permanently. $\endgroup$ – SF. Oct 9 '18 at 15:03
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    $\begingroup$ @SF I think that's the best point, "why"? We haven't really concretely said there is a solid benefit to having block-chain over traditional calculations (in terms of ephemeris elements anyway). In fact there's many, many drawbacks. It'd be like being those start-ups that put "block-chain" in their name to attract investors. They forced it into their model, it may not even make sense. $\endgroup$ – Magic Octopus Urn Oct 9 '18 at 15:07
  • $\begingroup$ oh I just meant that one might need the info described in my question most in LEO, and that in LEO (in the future) there will be plenty of bandwidth. So "not enough BW in deep space" didn't seem to seal blockchain's fate. I think your autonomous swarm discussion is quite thoughtful. It may never happen, but if it did. $\endgroup$ – uhoh Oct 9 '18 at 16:35
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Note: This is an opinionated answer.

I doubt block-chain, in the conventional sense where the Merkle root contains transaction (money) data, makes sense for spaceflight. It's a pump-and-dump operation that should've died a long time ago, but didn't because people use it to make money off of those who are stupid. The whole idea behind "mining" the verification on "transactions" would be cumbersome for hardware in space.


Impromptu Case-study: Block-chain for something other than money?

The only thing I could see is block-chain in a non-conventional sense (possible keep track of impulse maneuvers as if they were money), but it really doesn't make sense at our current scale. Take for instance if we had a large number of satellites, maybe a 1000 node cube-sat network (this is still a micro scale), and we really needed them to ensure that all the maneuvers (transactions) they've accomplished position themselves in accordance with the cube-sat swarm. Maybe, with every maneuver that each cube-sat makes sends a message to a handler earth-side, creating the transaction blocks, and creating a block-chain where each satellite could track the full impulse motions of all other satellites from launch to current state vectors.


Problems

Average Block Size 0.66 Megabytes The 24 hour average block size in MB. Transactions per Day 212,753 Transactions The aggregate number of confirmed Bitcoin transactions in the past 24 hours. Mempool Size 1,774,772 Bytes The aggregate size of transactions waiting to be confirmed.

Source: https://www.blockchain.com/en/charts

Once again though, this requires computing power-- a lot of it, scaling up with every single day and every single maneuver added to the chain. While you can cache the block-chains after the first computation and do additive calculations to decrease complexity. This would require a lot of radiation hardened storage space that cannot deal with even a slight bit of corruption (block-chain caches are not radiation hardened).


Benefits?

On the plus side, however, you now have 1000 satellites that know where each other are, indefinitely. If one satellite goes down for awhile to the point where the memory is dumped (full power loss) attitude could be regained by reconnecting with the block-chain and calculating the cache again. This is just one example of a potential block-chain usage in space, I'm sure other people could come up with something much better. However, there are more conventional ways to fix attitude real-time (accelerometers, etc...). Usually the direct-math approach is better in terms of software complexity (time to execute) memory storage (how much you need to cache) and total efficiency. Why not just send the state-vectors of each satellite calculated from velocity as positioned from the stars cached every day?


I really think it circles back to the fact that we haven't yet seen a use for it. Other ideas like this may also be useful, but once again this is a macro concept; we're still on the side of a micro-spacex world.


Here's a Quora answer (yes I know, ew) about using Block-Chain in non-money situations:

https://www.forbes.com/sites/quora/2017/11/17/what-is-blockchain-used-for-besides-bitcoin/#59bc6cf2446e

It actually covers a lot of the true uses that have been appearing:

  • Detecting voter fraud.
  • Censuses.
  • Currency that doesn't require bureaucracy in times of crisis.

Mostly they've been shown as beneficial in areas where data is easily misrepresented-- like in scenarios with a lot of fraud, or ability for humans to "get their hands dirty". I guess this could extend to space to some degree, but in what ways I couldn't say.

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    $\begingroup$ Re, "1000 node cube-sat swarm..." You don't need blockchain to manage satellites unless each satellite acts as an independent agent that could further its own self-interest by cheating on the others. The purpose of blockchain is to facilitate cooperation and discourage cheating in an arena where everyone is competing against everyone else. A collection of satellites isn't a "swarm," unless they all cooperating with each other to achieve some common interest. $\endgroup$ – user27176 Oct 9 '18 at 15:48
  • $\begingroup$ @besmirched I was saying that the swarm could be self-aware of it's other nodes for autonomous positioning between each node in the swarm. They could be cooperating to achieve total global coverage using an autonomous swarm, as I had stated "to ensure that all the maneuvers (transactions) they've accomplished position themselves in accordance with the cube-sat swarm." There's definitely common interest in knowing where its brothers are at any time if the 1000 are attempting to perform a concurrent task. You're pretty much just stating the point I was trying to make, albeit more clearly. $\endgroup$ – Magic Octopus Urn Oct 9 '18 at 15:50
  • $\begingroup$ Sure, but if they're cooperating, then you don't need blockchain. $\endgroup$ – user27176 Oct 9 '18 at 15:51
  • $\begingroup$ @besmirched I never stated we needed blockchain. I was just stating how it could be used. "Why not just send the state-vectors of each satellite calculated from velocity as positioned from the stars cached every day?" and 'Mostly they've been shown as beneficial in areas where data is easily misrepresented-- like in scenarios with a lot of fraud, or ability for humans to "get their hands dirty".' $\endgroup$ – Magic Octopus Urn Oct 9 '18 at 15:52
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    $\begingroup$ @besmirched so, kind of like, how you could attack another argument nobody was making instead of the argument stated? We agree with each other. I don't think you fully read my post. $\endgroup$ – Magic Octopus Urn Oct 9 '18 at 15:53

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