Some large community of space enthusiasts is working hard on simulating or extrapolating data on the SpaceX Starship. But this data isn't publicly available.

So why don't they release it as an open source project? Or at least support those who want to create their own open source project?

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    $\begingroup$ the boring answer is probably ITAR and wanting to control IP. Not an open source expert but suspect there is a valid answer drawing from successful VS unsuccessful open source projects. In fact has there ever been a successful open source HARDWARE project? Contributing to Starship would really require access to hardware to validate your contribution. $\endgroup$ Commented Jan 26, 2021 at 0:14
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    $\begingroup$ I've added the business and regulatory tags since as the previous comment points out there are business reasons to keeping some technology proprietary, as well as regulatory reasons for keeping it secret, and making a project open source would challenge those in some ways. $\endgroup$
    – uhoh
    Commented Jan 26, 2021 at 0:28
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    $\begingroup$ Has SpaceX ever indicated they want to work with random contributors on this? They seem much more likely to want to control the project end to end, as that gives them the full ability to tailor the direction specifically to that of SpaceX's business plan, surely? Even open source software projects have gatekeepers which keep the project on very tight rails, which is why forks happen and competing development occurs - its not a free for all where everyone wins all the time... If this helps, I can flesh it out into an actual answer rather than a bunch of requests for clarification. $\endgroup$
    – Moo
    Commented Jan 26, 2021 at 3:13
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    $\begingroup$ I’m voting to close this question because it's off-topic to space exploration. And almost certainly opinion-based. $\endgroup$
    – RonJohn
    Commented Jan 26, 2021 at 18:18
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    $\begingroup$ I normally avoid deeps edits like this, but I felt that the rambling verbiage obscured what is a pretty good question. $\endgroup$
    – Machavity
    Commented Jan 27, 2021 at 15:53

4 Answers 4


There are many reasons. They include money, intellectual property, regulations, and Elon Musk.

Money. Building open source software is relatively inexpensive, sometimes ridiculously inexpensive. No equipment is needed as most programmers have their own computers. There are many open source software projects where the developers do their work for free. Occasionally commercial companies will release some of the software developed in-house as open source, sometimes as a benevolent charitable pay back for all of the open source software they use freely, sometimes in the hopes that external developers will enhance the product, for free. As an example in the space exploration industry, Ball Aerospace made their COSMOS software open source.

Building rockets on the other hand is ridiculously expensive. This is an endeavor that requires very expensive equipment, very expensive facilities, very expensive parts, and rather expensive employees. Elon Musk started SpaceX with \$100 million of his own money. When he showed that he might know what he was doing, he received a downpayment of what would eventually be almost \$400 million from NASA.

That huge investment from NASA was made without NASA getting a stake in the company. NASA was looking for alternatives to the broken cost-plus contracting mechanisms that NASA traditionally used to build new rockets and new spacecraft. That investment was however made with the requirement that the companies that participated in the Commercial Orbital Transportation Services (COTS) project had to obtain significant amounts (hundreds of millions of dollars) of private financing to show the companies had skin in the game. SpaceX did so. Rocketplane Kistler did not, and their COTS contract was cancelled; that company eventually collapsed.

Elon Musk did not use a hundred million dollars of his own money to start an open source project, nor did those private investors.

Intellectual property. One of the key assets of any technology company is its intellectual property, and SpaceX has a lot of intellectual property (IP). Those private investors would have invested zero dollars in SpaceX had Elon Musk said that all of the SpaceX IP would be placed in the public domain.

Regulations. Even if Elon Musk did want to put all of SpaceX's IP in the public domain, there are multiple regulations that would have prevented him from doing so. The US government views rockets capable of going into orbit as advanced weaponry. The International Traffic in Arms Regulations (ITAR) and Export Administration Regulations (EAR) place severe penalties on companies and individuals who release restricted information to other countries, including countries that are US allies. The penalties on companies involve massive fines. The penalties on individuals involve large fines and substandard government-funded room and board (i.e., prison.) Hosting the plans, schematics, flight software, etc. for a rocket on GitHub would result in people going to jail.

Elon Musk. Elon Musk is a strong personality. He does not believe in patents, which is a way of open-sourcing an idea (with a fee). He instead wants SpaceX and Tesla to guard their IP as trade secrets. Musk organizes his companies vertically rather than horizontally as this gives those companies much better control over the supply chain and much better control of its IP. There is no way Elon Musk would have thought for even a second regarding making SpaceX an open source project.

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    $\begingroup$ There is very little difference between the design of a space cargo rocket and an ICBM (inter-continental ballistic missile), which is why the public knowledge of how to build rockets is restricted by international treaty $\endgroup$
    – CSM
    Commented Jan 26, 2021 at 10:38
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    $\begingroup$ @CSM Citation needed. There are many international students who study aerospace engineering and related topics in US universities. There are many international members of the American Institute of Aeronautics and Astronautics who receive journals such as the Journal of Spacecraft and Rocketry. $\endgroup$ Commented Jan 26, 2021 at 12:34
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    $\begingroup$ @CodeswithHammer There is no mention of a treaty in that handbook. The ITAR and EAR are, as far as I can tell, regulations made unilaterally by the US rather than because of a treaty. $\endgroup$ Commented Jan 26, 2021 at 14:18
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    $\begingroup$ @CodeswithHammer I am not saying that rocketry is subject to the ITAR and EAR. To the contrary! I explicitly wrote in my answer that "Hosting the plans, schematics, flight software, etc. for a rocket on GitHub would result in people going to jail." $\endgroup$ Commented Jan 26, 2021 at 14:47
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    $\begingroup$ @DavidHammen ITAR specifically doesn't restrict sharing textbook knowledge or concepts taught in school but it does restrict sharing of a detailed design. Going from textbook concepts and journal articles to detailed schematics/models for an actual design that you could send out to machine shops and circuit card manufacturers would probably take 10s of thousands of engineering hours. $\endgroup$
    – user4574
    Commented Jan 28, 2021 at 15:22

In addition to David's answer, I would like to add:

Safety: Developing software for safety relevant use-cases like spaceflights, airplanes, self-driving cars... requires a completely different development approach compared to most open-source projects.

This include the software itself, which must take many regulations into account. They require things like redundant computing, regular system self-tests and so on, which must be planned from the beginning in the software architecture. An open mind community which brings a constant stream of new ideas into the project is not something you want to have here.

Also, the software will require a development process with lots of documentation, testing and certifications to make sure the system will work properly, especially if humans are using it.

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    $\begingroup$ "Open Source" does not mean that everyone can contribute. Some open source projects operate that way, but many others do not. For more information I recommend The Cathedral and the Bazaar. (the author who coined these terms is very pro-Bazaar, but many other projects still prefer the Cathedral model). $\endgroup$
    – Philipp
    Commented Jan 26, 2021 at 10:55
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    $\begingroup$ Safety-relevant software is still built from open-source components and that's not a slightest obstacle for having it certified. Someone has to do the validation and testing, but the source can still be public. And some control over what gets added is useful to keep the testing simpler, open-source project can have that. $\endgroup$
    – Jan Hudec
    Commented Jan 26, 2021 at 12:33
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    $\begingroup$ This answer is completely incorrect. Nothing about publicising your research inherently makes your project less safe - in fact, for something like this, it could be much to the contrary. Experiments and data can be independently replicated/verified to find more potential errors. Open-source maintainers don't need to accept contributions at a lower standard than the project needs in order for it to be meaningfully "open source". You're conflating "open source" with "amateur" and "illegal". $\endgroup$
    – iono
    Commented Jan 26, 2021 at 15:22
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    $\begingroup$ <Irony> Sure, closed source software development avoids all these problems. Two excellent examples was Boeing's MCAS system for the 737 MAX, and before that the "fire-proof" battery management system for the Boeing 787. <\Irony> $\endgroup$
    – alephzero
    Commented Jan 27, 2021 at 11:09
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    $\begingroup$ @RussellMcMahon isn't the Stack Overflow security breach actually an example of failed security for closed source software? $\endgroup$
    – Kirk Woll
    Commented Jan 27, 2021 at 17:32

Frankly, until 3d printing gets significantly better (as in print circuit boards and complex electronics better than printers print thermoplastics today), "open source hardware" doesn't really make sense because it doesn't have the key advantages that open source software does:

  • Accessibility: Anyone with an internet-capable device can download an IDE, git, and a programming language and go to town. This means that a 16 y/o schoolgirl living in New Delhi can contribute just as much as a centenarian retiree who lives on a ranch in Indiana. In contrast, even the simplest open source hardware projects require manufacturing capability which very few people have. To get started with even the low end of projects, you're going to need to shell out at least several hundred on a 3d printer.
  • Individual skill: Writing code is both easier to learn and easier in general than engineering a physical product. Anyone can access a free online learn-to-code course and with zero investment besides time, become a proficient programmer. Engineering on the other hand basically requires higher education or some sort of apprenticeship program.
  • Iteration speed: The iterative cycle on writing code is potentially in the seconds range. I can type some code, click compile, test it, and be back to writing code in several heartbeats. Engineering on the other hand requires a longer iteration cycle. Even in "rapid prototyping", you're still waiting hours minimum for a 3d-printer to spit out a part and if you include more complex manufacturing processes (electronics) you're waiting days for shipments and spending hours soldering.
  • Collaboration ease: With version control software like git, multiple coders can easily work on the same project and then merge their results afterwards to combine their efforts. This is significantly harder in engineering as you can't "merge" drawings, sketches, or CAD files (collaboratively making an assembly works but is difficult). Additionally, to properly work on any hardware project, you need the physical prototype to test and experiment with. This means that anytime anyone in the project team makes a change to the master branch, everyone would need to re-download and re-manufacture the latest changes.
  • Professionals and money: Frankly, anyone good enough at engineering to contribute to a cutting edge project like Starship is either a) Already employed or b) Unemployed and looking to get paid for work.
  • Individual benefit: Open source works because individuals want to use it. OpenHab (a home automation software) is used by people who want to automate their home, and when they find software glitches in the system, the fix and share them because this benefits them directly. Working (for free) on a project like Starship brings no at-home or future benefit to the contributor (outside of maybe feeling good about it).
  • $\begingroup$ The people working for Relativity Space would strongly disagree with your conjecture regarding 3D printing. They think that 3D printing is a very good idea for making rockets. Of course, their 3D printing technology is not open source. It is their central piece of intellectual property, and they presumably guard that IP very closely. $\endgroup$ Commented Jan 30, 2021 at 9:45
  • $\begingroup$ @DavidHammen You're right, but my point about 3d printing is not about the actual additive manufacturing process but rather the democratization of at-home making that consumer grade printers have born over the last decade. Even if Relativity Space's printer can print a rocket, people don't have a Relativity Space-quality printer at home so they wouldn't be able to contribute to any open source design. $\endgroup$
    – Dragongeek
    Commented Feb 2, 2021 at 14:09
  • $\begingroup$ Downvoted because this seems to focus too much on spurious arguments against open source hardware (which is a thing, does work, and I've taken advantage of it)... and not enough actually talking about what opensource would mean for starship. $\endgroup$
    – NPSF3000
    Commented Feb 2, 2021 at 16:43

The answer is very simple: capitalism.

The implicit and/or systemically-rewarded goal of any privately-owned (as opposed to democratically-controlled, not state-owned or publically-traded) company is to profit as much as possible. SpaceX publicising the data from its development efforts could potentially benefit other companies or government organisations that might compete with SpaceX; SpaceX is using "closed-source" / intellectual property laws to retain its "first-mover advantage".

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    $\begingroup$ That doesn't explain why a large number of open source projects have been developed and thrived within a capitalist society of the USA and Europe but this one hasn't been open source. $\endgroup$
    – ikrase
    Commented Jan 28, 2021 at 4:11
  • $\begingroup$ @ikrase Open source can be profitable to certain capitalists in certain circumstances, but not others. It was capitalists who actually supported legally abolishing child labour in Britain during the Industrial Revolution: an individual capitalist would lose out in the short term by abstaining from child labour, but if they collectively did it through the state, it was in their collective class interest: preventing workers from en masse early deaths made them, on the whole and in the long term, more productive. Sometimes "the right thing" aligns with profit, sometimes it doesn't. $\endgroup$
    – iono
    Commented Jan 28, 2021 at 7:56
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    $\begingroup$ "In SpaceX's case, it is a publically-traded company" – Citation needed, as they would say on Wikipedia. $\endgroup$ Commented Jan 28, 2021 at 11:18
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    $\begingroup$ "In SpaceX's case, it is a publically-traded company" -- This is not the case, so very much not the case. Elon Musk has intentionally made SpaceX not be a publicly traded company. It is not listed on any stock exchange. It is instead a privately financed company. Elon Musk does not want to even chance being overruled by a SpaceX board of directors or by the various public meetings a publicly held company must endure, and he especially does want to chance being kicked out as the CEO. This answer is flat-out wrong. $\endgroup$ Commented Jan 28, 2021 at 11:40
  • $\begingroup$ I'd upvote this if you corrected the "publicly traded company" thing. $\endgroup$ Commented Jan 28, 2021 at 19:16

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