I have a question about my Space Exploration Stack Exchange post: Is a railgun up Olympus Mons possible?

The error I'm getting is "Sorry, we are no longer accepting answers from your account because most of your answers need improvement or do not sufficiently answer the question. See the Help Center to learn more.".

I think that when Rory flagged an earlier answer that I posted as spam (because I included a link to a video) he effectively blocked me from posting.

I promise to be more careful with what I post in the future.


So first, thanks ErinAnne for taking the time to share your thoughts. I'm sure that they are representative of the community as a whole.

Initially, this question was about just one deleted answer, but Erin's response below is more holistic in nature. I recently answered three questions:

The first question asked...

Alternative small mass payload transportation from the moon to L5 besides rail gun and mass driver?

This question asks about a low cost transportation from the lunar surface to a space settlement at L5.

Moon mining is can be a revolutionary breakthrough in sustaining a space economy, but large scale transportation from the moon always seems to be an issue. The usage of transport rockets every now and them would exponentially drive up expenses.

When researching this topic, an electromagnetic rail gun and a mass driver were the only feasible options which I could find.

Are there any other concepts that are perceived as both technologically and economically competitive with two"

It had three upvotes and no answers at the time. I felt that the asker was looking for other relevant concepts, perhaps because they are interested in completing an exhaustive literature search.

My answer was...

There is a concept called a twin variable pitch screw launch system which you can learn more about from a video called "Why Don't We Just Launch Rockets With Launch-Assist Infrastructure?" on YouTube. The video describes a electromechanical launch system that is able to achieve high launch speeds at reasonable accelerations without some of the disadvantages associated with coil guns or rail guns.

Erin Anne also reminded us of the rules, which say:

Avoid overt self-promotion. The community tends to vote down overt self-promotion and flag it as spam. Post good, relevant answers, and if some (but not all) happen to be about your product or website, that’s okay. However, if you mention your product, website, etc. in your question or answer, you must disclose your affiliation in your post.

It appears to be ok to post about your own work, so long as you disclose your affiliation. The answer was a fairly dry description of what the video is about - not overtly self-promoting. What I should have done here was to provide a link to the peer-reviewed IEEE paper instead as well as the Ascend2023 paper, disclosed my involvement in the development this concept, and included some additional information from the papers in the answer so that the answer would have been more self-contained. I'm not sure if the link to a video should be included or not. The IEEE paper is behind a paywall. The video of the Ascend presentation is more recent and up-to-date. It includes 3D renderings of the proposed concept captured from our digital twin and the results from a parametric study. I think it adds value, but I would like to hear other people's opinions on that.

Erin also said, "I believe this poster is trying to promote their own work because it's not popular and because, frankly, it's not very good."

There is some objective data on the popularity of my work. A popular YouTuber and president of the International Space Society, Isaac Arthur, released two videos that have covered it. The first is entitled Tethered Ring Space Launchers which has 121K views and the second is entitled Interplanetary Infrastructure which has 114K views. Issac shares his thoughts in the video's narrative and there are plenty of raw unfiltered comments that you can browse through to get a sense of what his followers think.

As for whether or not is very good, that's a job for the peer-review process to determine. We don't know enough about people on this site to say whether or not they are qualified to review a scientific paper on any given subject. They can use the voting buttons, that's ok. But, for example, marking something as "spam or offensive" is not, as far as I know, an acceptable way for someone to express that they strongly disagree with the validity of the points being made in an answer. (This comes into play when we get the third question, below.)

The second question asks Is a railgun up Olympus Mons possible?

It starts off, by saying "I know Earth's atmosphere is a show stopper for rail gun launch to orbit from Earth's surface."

I have seen other posts (Feasibility of a small mass driver? and Why didn't NASA use the shuttle to make a profit?) where the question makes an incorrect assumption and people correct it in the comments or in their answers. Also, because a commenter challenged the lack of evidence, I modified my answer so that it included that evidence. I added a link to a video interview that Fraser Cain released recently. I was in the process of addressing other comments when the answer was deleted. However, since then, I have completely rewritten my answer to this question. It is now much more on point and I think everyone will approve of it.

The third answer was to the question What are the biggest challenges for high altitude rail-gun launch systems?

My answer to this got flagged as "spam or offensive content", even though it didn't include any links or mention any of my work at the time it was deleted. MessageI think what is at issue here is whether people agree with the answer. I'm still willing to work with everyone to improve the tone and impartiality of this answer. By its nature, it is asking for an option. One concern that was raised is that my answer also gave non-technological reasons and in the question description's summary the poster said "What are largest technology obstructions required for such a launch system?" But I think we should expand when it makes sense to do so, and not fail to provide valid reasons just because the asker limited the scope when they posed the question. Stack Overflow's founder, Jeff Atwood said...

I wish more people understood that the goal of Stack Overflow is not "answer my question" but "let's collaboratively build an artifact that will benefit future coders". Perhaps SO could be doing more to educate people about this.

So, I don't think that this should have been flagged as spam or offensive. It certainly wasn't "spam" when it was deleted. So, the first question we need to ask is "Was it offensive?" Here is the answer at the time it was deleted...

The biggest challenges are:

The technological inertia of chemical rockets left over from the cold war and the moon race. We invested a lot of money and we continue to invest money in chemical rockets. NASA makes the Kennedy Space Center available for launch and pays companies handsomely to resupply the ISS, which helps to subsidize rockets. The DoD is also most interested in funding those startups that are most likely to grow up to become alternatives to the big-5 defense contractors.

In the delta-v range between 0 and around 8000 m/s, it can be argued that rockets scale better than rail-guns and other kinds of systems. Rockets start to run into serious scaling challenges beyond this when the exponential effect of the rocket equation kicks in and forces rocket costs up into the into the billions and then trillions of dollars. Fixed infrastructure cost scales more gradually - somewhere between delta-v squared and delta-v cubed - instead of exponentially. Therefore, fixed launch infrastructure becomes more cost-effective than rockets when the delta-v requirements are higher (e.g. above 8000 m/s).

The effects of atmospheric drag and the difficulty of maintaining a vacuum inside a tube are often misrepresented in discussions on various forums. People who grew up in the world of trains, planes, and rockets are more likely to perpetuate the notion that these problems are hard to solve, but projects like LIGO, where they routinely maintain a vacuum of one trillionth of an atmosphere within km long stainless steel tubes, show how far we've really come. Plasma windows have been demonstrated as a technology that may be useful for keeping the atmosphere out at the exit of the launch tube.

There is information circulating on the internet that suggests that, after 50 years, the cost of chemical rockets has suddenly started trending down dramatically. There is a significant difference here between the hype and reality and that hype misleads investors.

After that issue of "spam or offensive content" is decided, we need to discuss whether the answer needs to be improved. I agree that it does. My goal is always to produce an answer that will be upvoted by the community because it articulates a valuable and credible perspective - even if it is a perspective that not everyone happens to agree with. Case in point, my perspective on launch costs being higher than lots of internet content producers seem to think is a minority perspective, but it is well supported by hard evidence.

If we label an answer that attempts to address misinformation as "spam or offensive", then we are being complicit in the propagation of that misinformation. So, if deep down it is really the message that is bothers you about this post, please see it in your hearts not to shoot the messenger!

  • 1
    $\begingroup$ keep in mind that the existing answer to that question does a rough estimate to say "yes, we've already designed vehicles that would survive that launch, so it seems possible." What is your answer going to add? If it's about Earthbound railguns also being possible, that's an answer to a different question. If it's about misinformation about railguns, that's an answer to a different question. What kind of answer do you intend to write? $\endgroup$
    – Erin Anne
    Commented Dec 3, 2023 at 22:13
  • 1
    $\begingroup$ To improve upon the previous answer, I provided a more accurate estimate and explained how to do the math, added two figures, and I also expanded a bit more on the pros and cons of the mass driver relative to rockets on Mars. I also explained that dust might be a problem for a rail gun on Mars. If you don't think that it is a significantly better answer, I am still willing to work with the community to improve it. It avoids mention of any of the technologies that I've been involved in developing. $\endgroup$
    – phil1008
    Commented Dec 4, 2023 at 5:41

1 Answer 1


I feel like I am going to get into an internet fight, which I shouldn't do, but I also think I've seen some information relevant to whether or not spamming has occurred that others might not have noticed (because I didn't initially).

Short story is--three answers were posted. Part of the reason they looked like spam is they were, in part, link-only answers pointing to a Youtube video for the relevant information. Judging the value of the video was never part of the equation; if it looks like spam, you don't click the link. That's how internet works.

But one of the answers that got removed wasn't quite link-only. It had some actual keywords to start from: a "twin variable pitch screw launch system." Some discussion occurred in the comments that I didn't pay much attention to initially, but I actually got curious about maybe voting to undelete and making a meta case that, though this answer still needed improvement, it might not count as outright spam.

Then I noticed that the linked paper was from kind of a weird-seeming website. I glanced at the video, and it's at least affiliated with the same group (and I assume it's a presentation of the same project but I'm not going to check). It's all self-promotion, without any mention of the poster's affiliation. That's against the rules and we have an entire tips page about how not to be a spammer.

So now we're basically only arriving at why the OP is probably asking this question at all; the rules have been noted, ok, let's repost inside the rules with an admission of affiliation or whatever.

Here's the main thrust of what I want to say: I believe this poster is trying to promote their own work because it's not popular and because, frankly, it's not very good. We're already rightly wary as a community of people posting their pet ideas (there's an entire tag devoted to that in part so such questions can be filtered out). The paper linked to about the "twin variable pitch screw launch system" includes a simplistic analysis that estimates the cost of said Earth-surface-to-orbit megastructure launch system, a 3,750km long launching track, at \$15 billion USD. That's pure lunacy; a pedestrian bridge costs \$2,500 to \$3,000 per linear foot, more than twice as much per-length (Wolfram Alpha tells me a 3,750km pedestrian bridge would cost $36.91 billion dollars, which obviously doesn't include any of the scaling factors that would come into play).

So yeah, all that to say:

I worry that the ideas this poster is trying to promote are low-quality to begin with, but dressed by things like being published by the IEEE / presented. We should be wary as a community of letting OP use StackExchange to better-position their ideas in search engines, because some people will take them seriously instead of engaging critically with what's being presented.

afaik this decision rests with the mods, not me or the community (though the community's later votes and flags would have their effects), but my opinion--whatever that is worth--is that any self-promotion OP does of their work is going to spam of the type that we shouldn't accept.

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    $\begingroup$ come to think of it, should I have linked to the paper here? is SpaceSE Meta also indexed by Google? $\endgroup$
    – Erin Anne
    Commented Dec 3, 2023 at 23:21
  • $\begingroup$ Thanks Erin, for taking the time to explain. I really appreciate that. I understand why you are wary. I've come across lots of ideas in my field where I share your point of view (e.g. space solar power and space elevators). I came across the alternative-small-mass-payload-transportation-from-the-moon-to-l5 question and answered it first. It had zero answers. Because I had published about the twin screw launcher in the peer-reviewed proceeding of IEEE Aerospace and presented on it at Ascend2023, I felt that it was legit by SE standards and of interest to the person who asked the question. $\endgroup$
    – phil1008
    Commented Dec 4, 2023 at 5:20
  • $\begingroup$ Regarding the sentence "Then I noticed that the linked paper was from kind of a weird-seeming website." The originally published paper can be found here: ieeexplore.ieee.org/document/10115896. The link took you to an updated version containing some corrections hosted on the Project Atlantis Website. If that website gave you the impression that it's "weird-seeming", that's not good! I would love some more feedback from you on that. $\endgroup$
    – phil1008
    Commented Dec 4, 2023 at 20:18

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