*YEET*ing to orbit @ TL=5-8 (pre-gravitics)

[Spinward Flow]

 

[Spinward Flow]

 

[Grav_Moped]

Spin launch requires extremely hardened payloads.

Now, if you could build a beanstalk, that'd be something. And an entirely different set of problems and failure modes.

 

[whartung]

Spin launch requires extremely hardened payloads.

This is actually misleading.

Not that it's not true, the payloads suffer very high Gs, but it turns out lots of payloads can naturally survive high Gs, so in practice it's less of an issue than they thought.

Just the fact that they've demonstrated solar panels that can take those forces (which, intuitively. one might think are particularly vulnerable to it), shows a lot of the "hard questions" regarding this have been solved. Circuitboards take the Gs pretty well, apparently, too. If they can manage to not flatten the liquid fuel tanks during spin up, it just might work.

Downside is that they have apparently been rather dark about progress since the 1/3rd scale work a few years ago.

 

[Commander Truestar]

Grav_Moped said:
Spin launch requires extremely hardened payloads.

This is actually misleading.

Not that it's not true, the payloads suffer very high Gs, but it turns out lots of payloads can naturally survive high Gs, so in practice it's less of an issue than they thought.

Just the fact that they've demonstrated solar panels that can take those forces (which, intuitively. one might think are particularly vulnerable to it), shows a lot of the "hard questions" regarding this have been solved. Circuitboards take the Gs pretty well, apparently, too. If they can manage to not flatten the liquid fuel tanks during spin up, it just might work.

Downside is that they have apparently been rather dark about progress since the 1/3rd scale work a few years ago.

Sadly, no, what @Grav_Moped said is not misleading
This is most highlighted by the research of Andy Weir in writing his novel "The Martian", where a resupply rocket carrying non-standard food rations experienced liquefaction during launch due to powerful vibrations.
The result was that the solid rations turned into a liquid the movement of which intensified by vibrations and caused harmonic oscillations
A pressure wave then developed and breaching the rocket's sidewall while causing aerodynamic forces that tore apart the rocket's second stage
Now, while that example was a fictional scenario, the research behind it highlights the dangers of liquefaction

This phenomenon poses A REAL THREAT in the transport of certain bulk cargoes. Liquefaction occurs when granular materials, often with high moisture content, transform from a solid to a fluid-like state under agitation. And those launch vibrations or movements would encounter a massive increase using Spin Launch.

While the claim by @whartung is correct that "some" solid cargoes such as solar panels and circuit boards can take the strain, his claim is short sighted.

In real world examples, Liquefaction is a phenomenon in which a soil-like material "HAS" abruptly transformed from a solid dry state to an almost fluid state. Many common bulk cargoes, such as iron ore fines, nickel ore and various mineral concentrates, are examples of materials that may liquefy. If liquefaction occurs on board a vessel, the stability will be reduced due to the free surface effect and cargo shift, possibly resulting in capsizing of the vessel.

DNV GL has updated a guideline for the design and operation of vessels with bulk cargoes that may liquefy. The intention of this guideline is to raise the awareness of the risks of cargo liquefaction on ships and to describe what mitigating actions may be taken to reduce such risks.
(https://www.dnv.com/maritime/publications/bulk-cargo-liquifaction/)

As such, Spin Launch has many issues which remain to be solved before I would say it is safe to use

So, while you can use SL IYTU, I recommend you actually investigate the science instead of simply assuming what you've heard is correct.

 

[whartung]

Ya know, its a funny thing about Spin Launch.

Everyone seems to think that the SL folks are just ignorant. That they don't know math, engineering, material science, the market, the need, or anything else. That it's all a complete boondoggle. Everyone else seems to know better, but not the folks actually doing the work. Blind idealists.

I don't think launching up bulk anything is a goal of their system. Pretty sure they're not planning on putting people, dogs, bunnies, cans of tuna, or other organic things in their payloads either. But things like electronics and (apparently) solar panels? Things that are, you know, common to satellites? Apparently they, after testing (of all things), feel it can work.

The problem they're facing right now, honestly, (and I don't know, I have no idea) is probably Space X and their reusable launch platform. I don't know what their $/kilo estimate is for SL, but SX pretty much has the current corner on hurtling lots and lots of satellites into space. So, it may well be a market issue that they're facing, rather than an actual engineering issue.

And that may make it that much less viable.

But who knows.

 

[Commander Truestar]

Ya know, its a funny thing about Spin Launch.

Everyone seems to think that the SL folks are just ignorant. That they don't know math, engineering, material science, the market, the need, or anything else. That it's all a complete boondoggle. Everyone else seems to know better, but not the folks actually doing the work. Blind idealists.

I don't think launching up bulk anything is a goal of their system. Pretty sure they're not planning on putting people, dogs, bunnies, cans of tuna, or other organic things in their payloads either. But things like electronics and (apparently) solar panels? Things that are, you know, common to satellites? Apparently they, after testing (of all things), feel it can work.

The problem they're facing right now, honestly, (and I don't know, I have no idea) is probably Space X and their reusable launch platform. I don't know what their $/kilo estimate is for SL, but SX pretty much has the current corner on hurtling lots and lots of satellites into space. So, it may well be a market issue that they're facing, rather than an actual engineering issue.

And that may make it that much less viable.

But who knows.

No one - I hope - feels the engineers and designers behind spin launch are uneducated at all
And I certainly feel, based on my background and experience, that Spin Launch has its place in lofting cargoes.
However, side stepping the claim of ignorance, Spin Launch is limited.

In fact, per the experiences we've seen even in nautical cargo transit, Spin Launch is even more limited than outside observers realize.
Just as "outside observers" do not understand that filling an enclosed space with sugar powder can create as much of an explosion as aerosolized gasoline (Just google sugar plant explosions).

Yes, a pure solid lump of dense material with a rigid molecular structure can be spin launched if you can generate the needed vector.

But, the assumption that people who are not the engineers and designers are making is that Spin launch can and will have a much more broad application. That is, under current tech limits, not the case.

So, I - at the very least - am not making comments denigrating the knowledge, skills and intentions of those who are developing these systems.
I am pointing out known fact and theory at the state of our current tech.
Nor does it have to do with "Dollars per Kilogram".

If you can't get a payload to altitude without suffering failure due to liquefaction, that is a limit of material physics. Your cargo, or part there of, simply changes structure under the pressure required.

So, don't blame the math skills of the scientists for the assumptions we make here as we discuss them
And, don't mis-state my comments as A) being ignorant of the maths B) targeting the design skills rather than the facts of material science or C) attacking the scientists because I point out a poster's assumptions even correctly relate to the work being done by those scientists

 

[Spinward Flow]

I don't think launching up bulk anything is a goal of their system.

In a world without SpaceX and/or Stoke Space in the market, SpinLaunch might have been a serious competitor for launch services.

The bottleneck for SpinLaunch is that (currently) they're aiming for a payload market of up to 200kg ... and their launch system isn't something that can "rapid fire" (for lack of a better image). A single payload launch will take over an hour to depressurize and spin up for a single launch.

Let's be generous and assume 1 launch every 2 hours.
That's 12x 200kg payload in launches per day, if running the system 24 hours a day.

A single Falcon 9 can deliver 22,800kg to orbit.
Yes, the $ per kg will be higher on a Falcon 9 ... but you can deliver all that payload in a single launch.
For the purposes of comparison, you'd need 114 SpinLaunches to match that payload delivery (equivalence). That would take 9d 12h to complete 114 SpinLaunches ... and those 114 payloads would all be in different orbits, so if you've got a "some assembly required" payload that requires more than 200kg to aggregate, you're going to be "paying" for that in reduced payload (due to maneuver fuel required for launched payloads to rendezvous in orbit) cutting into your "useful" payload fraction.

The comparison gets MUCH WORSE when trying to measure up against Starship, both in terms of payload to orbit and business economics.

So SpinLaunch is really just playing for a MUCH SMALLER end of the launch market than what SpaceX and Stoke Space are aiming for.



200kg of payload capacity isn't a whole lot ... although it's certainly better than nothing.
It's basically microsatellite territory, as far as market segments go.



I'm personally less concerned about the engineering of SpinLaunch, since the notion is structurally sound from a standpoint of physics and engineering. The bigger problem is one of economics.

If a competitor comes along (say ... SpaceX with Starship) that can deliver massively bigger payloads (1000x in fact) at an even lower cost than SpinLaunch can provide for microsats (minus the 10,000G launch stress factor), then SpinLaunch is going to wind up on the wrong end of the "we make it up in volume" economic equation for viability as a company providing a service.

The main obstacle here (on the economics front) is Wright's Law ... that for every x2 of production, the cost of the product drops by X% (which can go as high as 30% in some industries). If SpinLaunch isn't able to SCALE (massively) then they won't be as competitive of a launch services provider ... which will then cause them to "wither on the vine" (so to speak) in a "winner takes most" competitive market where customers are price sensitive (I mean, go figure, eh? ).

Meanwhile, you've got SpaceX sitting over there with ambitions to launch 1000+ Starships every 2 years to Mars for decades.
Massive SCALE is the entire point and purpose of the program. It's kind of baked in to the notion of making humaniti an interplanetary species.
SpaceX is going to be putting Starships into mass production, unlike every other rocket company in history, once they get past the test program (that they're in now).