There are many small orbital launch vehicles proposed or under development | Hacker News Reader

There are many small orbital launch vehicles proposed or under development

orbitalindex.com

90 pointstectonic39 comments

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> How to make Plutonium [https://www.youtube.com/watch?v=-sh5XZo5wRE]

tl;dw: First get a few gallons of a (radioactive, poisonous, pyrophoric) transuranic element called neptunium.

I'm glad this didn't turn out to be an easy DIY video, since that would probably cause, you know, the end civilization. It's a possible solution to the Fermi Paradox: A civilization advances until someone posts simple instructions for making plutonium on shared hive mind storage.

It seems like the best way to evade a similar risk is to get the heck away from Earth as fast as possible, like the top of this blog post describes. The fact that a not-small gold rush is developing to do just that is the most hopeful news I've heard in approximately ever.

Ehhh, everyone (relevant) already knows the general process for making highly enriched uranium or Pu-239, and how to make a bomb with it once they get it. The issue is that actually implementing those things takes a ton of infrastructure, and until relatively recently that infrastructure was extremely visible. As gas centrifuges have replaced gaseous diffusion as the primary method of enrichment, though, the amount of - and visibility of - required infrastructure to refine uranium has decreased dramatically. 20 years ago enriching uranium in a cave would have been incredibly impractical, as the machines were just too large and required too much power. But today... :(

You need a nuclear reactor to supply the neutrons for transmutation into plutonium, so this isn't something you can do at home. That video just shows the preliminary step of making neptunium slugs to be irradiated.

The processes are all difficult from a chemical engineering standpoint. Most of the materials involved are toxic or radioactive or corrosive or flammable or several of the above.

Enrichment plants are smaller now. They used to be city-sized; now they're the size of a large WalMart.[1] But not garage-sized.

Incidentally, there's a huge glut of depleted uranium in uranium hexaflouride solution form. Hundreds of thousands of tons. This is what uranium enrichment plants have left over after they've separated out the good stuff, which is under 1%. There's not enough demand for depleted uranium to run it through the chemical process to get metallic uranium out. Potentially it could be used in breeder reactors, if there were any that worked well.

[1] https://earth.google.com/web/@32.43377912,-103.07864954,1041...

> You need a nuclear reactor to supply the neutrons for transmutation into plutonium, so this isn't something you can do at home.

Sure, but a simple graphite reactor for Pu production, like what most current nuclear weapons states have used, isn't particularly complex.

As you mention, the difficult and expensive part is apparently separating the Pu from the rest (PUREX). In the West, those plants go for $20 billion a pop, or about, although a would-be-proliferant could probably make do with something substantially cheaper.

AFAICS the current thinking is that thanks to centrifuges, nowadays the easiest path for a rogue state to develop it's own weapon is to use enriched uranium.

And yes, there's a lot of DU around. Except for kinetic warheads, counterweights in aircrafts, and such, there's not much use for it. Waiting for breeder reactors to be deployed on a large scale is the plan in practice, I suppose.

... Thanks to centrifuges, nowadays the easiest path for a rogue state to develop its own weapon is to use enriched uranium.

Maybe. South Africa used electromagnetic separation. Slow, but it works for a small number of weapons. Pakistan has both a plutonium and a uranium program, and they've been plugging away at it since the 1970s. North Korea seems to have taken the plutonium route first. So did Israel.

There is direct link to a summary done by C. Niederstrasser, Northrop Grumman engineer:

https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=4...

Could we be at the very beginning of a Cambrian explosion for space exploration? Exciting times.

Either that or the beginning of a new dot-com bubble.

Most of those smallsat companies are financially viable on the expectation that they capture a meaningful fraction of the smallsat market - like 1/5th or more. They can't all win - and that's assuming any of them win. SpaceX seems to be planning to own the rideshare market [0], and so unless a customer really cares about having a particular orbit that's going to be pretty tough competition.

0: https://www.spacex.com/smallsat

> Either that or the beginning of a new dot-com bubble.

The dotcom bubble was the start of a cambrian explosion.

Those two events are part of the same process, not wholly separate entities in which case one is bad and the other is good. They require eachother and cannot be unlinked. The dotcom bubble was not a bad thing, it was a necessary process of chaotic, sometimes idiotic, experimentation. It was an extraordinary good. The total sum of all capital destroyed during the dotcom bubble (which lasted less than four years) would fit into a corner of Amazon's present market value.

Unless you want to pretend that humans are all-knowing gods. In which case we require no experimentation, there are no foolish mistakes possible, no errors of judgment possible, no irrationalism or over-excitement is possible, no emotion is possible, no idiots and malevolent actors (eg con-artists) are possible. And so on.

We should all be hopeful - giddy in fact - if we're about to see a space-focused dotcom style bubble. Bring on the space bubble, do it right now, let's get moving with that. That will be truly extraordinary, it will signal what comes after: a real, massive, sustainable expansion.

The global Internet is beyond a magnitude more valuable - in every way you can measure it, whether in business transacted, value of tech companies, or how valuable it is to end users - today than it was at the peak of the dotcom bubble in 2000.

The naysaying is hilarious and pathetic. Like, let's not throw our best and brightest at solving these problems. No. That's a waste of money. I KNOW! LET'S THROW IT ALL AT CRYPTOCURRENCY AND ADVERTISING AGENCIES!! BEST IDEA EVER!

Most of the funding raised by smallsat and small launch companies is a rounding error compared to the amount of money tossed at bullshit companies useless crap.

Most of the companies looking at launching satellite constellations need lots of odd orbits.

And there are lots of companies doing this! Two looking at 100+ constellations local to me, and I'm in Adelaide, Australia.

It's possible that the bubble is in the companies and the rocket companies are spades. Or maybe there is no bubble and this is airmail and airplanes.

Do any of those constellations require only one satellite per orbit, though? Because if you need 5 satellites in that orbit, you're your own rideshare partner...

> They can't all win - and that's assuming any of them win.

While I agree with your general point, do we completely understand the opportunity that space launch/travel/exploration provides yet?

The opportunity may be exponentially bigger than we currently understand.

But smallsat launchers only make sense if they have a lower cost/kg (unlikely vs the F9) or if they're being used for an orbit/launch time that doesn't have enough demand for a rideshare. And if the space launch market gets big enough to support 100 smallsat launchers, a F9 rideshare into that special orbit will probably have enough takers to make it cheaper than the smallsat launcher would have.

Smaller diameter rockets have a much worse fuel ratio (because of fuel tank geometry issues), so there’s no way they’ll ever be cheaper than larger rockets. They fundamentally must use more fuel per kg of payload than large rockets because fuel tank wet mass to dry mass ratio increases linearly with diameter.

Right, and that's why smallsat launchers are only really viable for orbits/launches that can't be served by rideshares. Better to pay $5mil for an Electron to launch your smallsat than to book an entire Falcon 9, even if the $/kg is far higher.

Companies like Momentus [1] are happy to sell you a tug that will turn a rideshare to a common orbit into your unusual orbit.

SpaceX's rate for an Electron-sized payload is 1/6 the price of an Electron.

1: https://momentus.space/

I have to say, 5 km/s delta v is more than I was expecting from a tug like that. Still, I really wouldn't be surprised if adding one of those to your smallsat would cost more than $5m.

By launched volume, it seems like. By diversity of launch platforms ... maybe not. SpaceX seems poised to dominate everything with Starship, even small launch.

We pretty much are!

Both nanosatellite and small launcher companies are booming hard in the last few years.

With Kessler syndrome looming it may be the wrong kind of excitement

Low earth orbit satellites decay very quickly. Without extra boost most satellites launched by these rockets will reenter within a year or two.

On a wider note, I find the dramatic pessimism of our times rather unfortunate. It seems every technical advance is now met with some prediction of doom. I miss when technical forums were optimistic.

I havent researched the orbital dynamics much here, but wouldnt it be possible for the satellite fragments resulting from a collision at orbital speeds to have much greater speeds, possibly ending up in elliptical orbits with lower total drag? Seems like just waiting for orbits to decay after a Kessler syndrome like event wouldnt be feasible.

An elliptical orbit would require the perigee to be even closer to the earth further increasing drag.

It is possible for small fragments to potentially be moved to higher orbits (with counter balancing mass being moved lower) But the conservation of momentum prevents the vast majority of fragments from suffering this fate.

Baring exceptionally bad luck a collision in LEO would usually decrease the time before the orbit decays. Remember a debris field has more surface area than an intact satellite.

Yes, it is possible. If you get an explosion, many fragments will be in an elliptical orbit where they can stay longer than on LEO. But there is a trade-off here, the time during what a fragment is dangerous is exactly the same time it is in a high drag region, so if it's not feasible to wait for it to fall down, it is also not really dangerous either.

What I'm waiting for is orbital unlauch vehicles. That is, spacecraft that methodically collect and comoactify space debris.

As we launch more and more cheaply and frequently, the few thousand miles above Earth become littered more and more, even with all deorbiting or parking provisions.

Most satellites are on orbits that will eventually decay due to atmospheric drag.

While this is technically true for all satellites, what's important is the timescale on which their orbits will decay.

What is the distribution of the time scale of these orbits though? If 90% of these things take a couple months (or weeks or days or whatever) to decay and burn up it seems like a non-issue - or one that can be planned around. If the fat tail sits further out in time that seems like it could actually become an issue.

One of the junkiest places in orbit right now is around 800-1000km (mostly thanks to the Chinese ASAT weapon test 12 years ago and an unrelated collision between two satellites in 2009. There's also tens thousands of droplets of irradiated coolant that was ejected from Soviet nuclear reactors in 70s-80s). At 1000km it can take around 100 years for something to deorbit from drag (can vary a bit depending on unpredictable space weather events).

1000km is still in Low Earth Orbit, but lower parts of LEO decay more quickly, e.g. months years or decades depending on the orbit's height.

When you get into orbits higher than LEO (MEO: medium Earth orbit, GEO), the timescales before something reenters can get more geological. A GPS satellite (~20,000km up, near the middle of MEO) left to its own devices will stay up for hundreds of thousands, if not millions of years.

Thanks for the detailed response. Fascinating. Where do you come across this information? I’d also love to learn more about this nuclear event from Soviet spacecraft.

Some of my coworkers do work related to orbital debris. I've learned a little bit by osmosis (mostly the right jargon to type into Google to get useful query results).

The Soviet spacecraft were the slightly confusingly named US-A series, also called RORSAT in English. The Wikipedia article[1] is a good start, but you can find some more technical info if you search around for papers on "NaK droplets"

[1]: https://en.wikipedia.org/wiki/US-A

All of them will eventually, just a matter of time.

I think this link was posted here sometime ago:

https://www.lizard-tail.com/isana/lab/orbital_decay/

And most of them are really tiny compared to the space they occupy.

Stealing the swipe action like that is really scummy.

Otherwise it’s a pretty interesting article. Lots of amazing space projects going on lately.

I expect 95% of these projects will never reach orbit.

Here's something tangentially related.

https://www.youtube.com/watch?v=nuGSTn_F0FE

I saw a list elsewhere that was tracking ~200 companies building launch vehicles. I'd guess that 90% of them will be gone in a decade having never put anything in orbit.

This sounds like it may or may not be true. Is this all because of Elon Musk?

Not an insignificant part of it IS because of Elon Musk. SpaceX has been crazily successful, AND it has a high churn rate, so the know-how gets spread throughout the industry in startups like these. The latter may be bad for SpaceX (arguable?), but I think it's good for the industry.

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