Spinlaunch... Can it succeed?

[Rick Law]

Quick release, yes. Everything else you said, even whether it's a bracket or some other solution, not so much. Applying math to your contrived scenario you already know doesn't work (a single bracket of 6.5 sq in) is just a waste of effort. Especially since you already mentioned brackets (plural!) in the sentence before that. Of course they'll make the collective surface area large enough for the mechanism to actually work! If they use that mechanism at all.
...

Normally, I rather raise just the problem points and let the others get to the conclusion by themselves.  But that isn't working here...

Let me remind you, there is no known working example of anyone spinning it to that speed, so there is no known definitive list of problems, and no known solutions to the problems.

You made an error in saying I know the bracket (with 6.5 square inch contact area) wont work.  Actually, I don't know that a single bracket wont work.  It may work.  What I said was such bracket will exceed the pressure needed to make diamonds.  Saying that is very different than saying it it wont work.

I am not a material science expert.  A bracket that can hold 880,000lb may already exist and may even be available off-the-shelf.   What I do know is that the bracket must hold the force and must fully extract very very fast.

What is known are the numbers from mathematics.  There is no research they can do that will reduce the total centrifugal g-force.  And they want it to go fast (2.3km/second) that is the other challenge.  If the top-bracket releases 1 microsecond late, the bottom already moved 2.3mm deforming the rocket.  So a single bracket may well be the best solution.

But then how will the rocket hold it's shape?  That darn thing must hold 880000lb (there about, since not everything will be located at a single mathematical point). With the magnitude of the numbers, it will be problem every direction you look.  All are likely solvable, but very few of them will be easy.

So, now that I elaborated some more, was I my attempt of illustrating to you that "likely a lot of problems, likely solvable, but likely not cheap" a success?

...
I don't know what the quick release solution is. If I had to guess, some sort of multiple carbon sling setup so the load itself doesn't need be reinforced to support brackets from the high side. Probably some sort of pin system for release. Or explosive bolts if pins won't work.

As for cost, that's not true at all during the R&D phase. Long term yes, unless the competition has more business than it can handle.

Be it "multiple carbon sling setup" or any other setup, you can't beat physics.  You want the acceleration for the payload, you will pay for the force of acceleration.   Either linear, or centrifugal, or mix.  The sling is merely spinning incomplete circles, so you are still dealing with the same centrifugal force.  Like a spinning the wheel, once it get to that speed, that will be your centrifugal force. There is perhaps another universe with different laws of physics (and values physical constants) that is more favorable, but in this universe, we are stuck with these contrived math numbers.

For spinning, 11,000g (rounded) and 440lb (200kg) payload = 880,000lbs centrifugal.
2.3km launch speed = 2.3mm/microsecond.  The payload will have to deal with the increasing bending and uneven load distribution for every micro second the release is out of sync.

No amount of discussion can change those numbers as long as our universe's physics doesn't change.

Indeed the test and research on how to harden a particular payload object needs to be done only once.  Trouble is, the tested solution needs to applied to every copy of the object that you will launch.  The tested solution is likely expensive to apply.  Worst yet, any minor change to the payload object, you need to test that object over again.

Since I have been unsuccessful letting you infer deeper from what I say, so let me say this out loud: I said "likely very expensive" from reasoning and experience.  Similar to while I don't know how much 100lb of gold is worth today, but from experience, I know a 100lb of gold likely isn't going to be cheap today, tomorrow, or for the rest of the month...

[Rick Law]

Their cost must be lower than the regular rocket launch cost

Not sure that holds. If climate change gets figured in, for instance, it could be worth quite a bit of the price. Similarly, if it doesn't need the acres of safe space a rocket facility does then that can dent the price comparison.

With due respect, when it come to non-fiscal value such as climate change, discussion or comparison are likely fruitless.  Every one assigns different their own non-fiscal value to things, all such assignment are subjective to the individual and may or may not be shared.

Earlier in this thread, I was hoping SpaceX will succeed.  Then I start looking into what Starlink is doing, I had a conversion.  I think launching 42000 satellites is outrageous.  That amount of eventual junk is going to make space more dangerous, and astronomy heavily impacted.  With that change in my perspective, my current preference is launching is priced so high that none but a very few will launch. 

[PlainName]

With duly returned respect, the thread is about the practicalities (or otherwise) of spinlaunch, not your personal moral stance. I really doubt if NASA or anyone else is going to ask you if their rocket meets your cost/pollution sweet spot.

[DougSpindler]

Someone correct me if I'm wrong.  But I would think this would not work for the same reason we can't build a spinning space station to create artificial gravity.  With the knowledge/technology we have....  and we're not even close to figuring it out.

I'm honestly curious -- why can't we build a spinning space station?  I've assumed that we haven't so far because we don't need one, and we don't have the incentive to spend money on a station large enough to make this practical.  But is there really any reason, other than cost and desire, why we can't?  We're not talking about hundreds or thousands of G's here, but probably something like 1/2 G.  I think we have the knowledge and technology, or at least are close enough that figuring out the rest shouldn't be too difficult.

Here's a podcast which discusses why it hasn't been done.  https://www.nasa.gov/johnson/HWHAP/artificial-gravity
What I remember learning is we don't know of any material which would not fly apart due to the spinning or centrifugal force.  F=mw^2r  The deal breaker terms are the w^2 and r terms.  To build a stations with the material/technology we have would be so costly and use all of the aluminum we mine for 10 years it's just not practical.

Here's video explaining with an explanation.


Neil deGrasse Tyson has a podcast/YouTube channel StarTalk.  In one of the episodes he also explains why it's not practical.

Are you even reading what you type? In the same paragraph you both say it's a) impossible with current materials and b) we can do it, but it costs too much. Those claims are mutually exclusive. In fact, neither of your links make the (a) claim, so I have no clue how you "learned" that. As for (b) so many problems with the claim, starting with using yesterday's launch costs, the false assumption that aluminum is only/best building material for space, and choosing to price a luxury mega-station instead of something more practical as a proof of concept re human biology. The kicker is even with all that, that podcast came to the conclusion that those costs were affordable for the clientele it was designed for.

Claims are NOT mutually exclusive and are co-existing truthful statements.  With our current launch vehicles and budget we cannot build a space station with artificial gravity.  We don't have or know of any material which would withstand the G forces for that small of a structure.  To build a space station with artificial gravity which would not fly apart could be built if we were willing to spend the money to do it.  The size would be enormous and would require all of the aluminum mined in 10 years and tens of trillions of dollars.  So no, we No we don't have the technology to build something which would not fly apart.

[bdunham7]

So no, we No we don't have the technology to build something which would not fly apart.

Why would it be flying apart?

[DougSpindler]

So no, we No we don't have the technology to build something which would not fly apart.

Why would it be flying apart?

The forces which act on a spinning mass.

[bdunham7]

The forces which act on a spinning mass.

Presuming you design it to generate a 1g force at its outer perimeter, I don't see how the resultant forces would threaten any structure robust enough to hold atmospheric pressure.  It would have to be pretty flimsy to fly apart.

[Rick Law]

With duly returned respect, the thread is about the practicalities (or otherwise) of spinlaunch, not your personal moral stance. I really doubt if NASA or anyone else is going to ask you if their rocket meets your cost/pollution sweet spot.

Yeah, sadly I have to agree with you.  What we average Joe thinks, pros or cons, right or wrong, wouldn't matter.  The ones who has the big bank accounts to attend the "election fund raising dinner" will drown our voice out.

The reply did served my purpose to explain my reason for my avoiding a discussion on it: non-fiscal value cannot be compared as each individual assigns their own.  So agree or disagree, comparing them just isn't meaningful.

[DougSpindler]

Appears Dunning Kruger forces re in effect if you think NASA and Neil deGrasse Tyson’s explanation isn’t accurate.

[PlainName]

Having read the NASA link it looks to me like the reason they're not doing it is a) because it's 'expensive' and b) they don't need it. They've been looking at it for decades and coming up with different plans, but it's been put off all the time because alternative solutions that are significantly cheaper are used. Nothing impossible about it or too costly - expensive does not mean impossibly costly.

We're still looking at the possibility as we start looking at commercial carriers. There's at least one commercial carrier that actually designed in a short-radius centrifuge to the design. And so, they are not ready to fly that yet but if there's a need, then we might be able to do that and back away from the station.

Is that the NASA explanation that's accurate?

[CatalinaWOW]

As I understand it the reasons spin gravity has not been used have nothing to do with structural issues.  More with operational complexity (docking with spinner, making observations and so on) and concerns about psychophysical affects of coriolus forces in small scale implementations.

None of these are huge problems, but people continually forget that getting to and operating in space is very hard, so even small problems become large.  If Musk succeeds with his Starship system many of these issues will be revisited.

[DougSpindler]

My mistake….  We, meaning the Russians, have already created artificial gravity in space.  So yes, it is possible and it has been done.  Something I just leaned is humans on earth have lived in artificial rotational gravity capsules on Earth.

https://youtu.be/nxeMoaxUpWk

For a related space topic you might be interested in the story of the Astrospies.
It’s story about the US and Russia program to get a maned spy station in orbit and staffed.  Spoiler alert, like with most of the space race the Russians won this one too.  And they were the fist to militarize space and fire a cannon in space.

https://youtu.be/URkD5W8FAFI

[CatalinaWOW]

My mistake….  We, meaning the Russians, have already created artificial gravity in space.  So yes, it is possible and it has been done.  Something I just leaned is humans on earth have lived in artificial rotational gravity capsules on Earth.

https://youtu.be/nxeMoaxUpWk

For a related space topic you might be interested in the story of the Astrospies.
It’s story about the US and Russia program to get a maned spy station in orbit and staffed.  Spoiler alert, like with most of the space race the Russians won this one too.  And they were the fist to militarize space and fire a cannon in space.

https://youtu.be/URkD5W8FAFI

There have been many tests of tethered objects, some with intent to provide an accelerated environment.  A google for space tether missions will give a fairly lengthy list.  The ratio of success to failure is informative and the analysis and observed data on susceptibility to space debris is also of interest.

[Rick Law]

As I understand it the reasons spin gravity has not been used have nothing to do with structural issues.  More with operational complexity (docking with spinner, making observations and so on) and concerns about psychophysical affects of coriolus forces in small scale implementations.

None of these are huge problems, but people continually forget that getting to and operating in space is very hard, so even small problems become large.  If Musk succeeds with his Starship system many of these issues will be revisited.

I would think cost and structural issues are the biggest problem.  Structural issues is not hard but it adds the cost significantly.

Docking is not a hard issue except as said in earlier replies, it adds to the structural issue.  Even during WW2 days, a cruiser can recover it's own launched sea-planes while moving.  They did it by towing a small floating mat along side, the sea-plane lands on water and move itself to be on top of that mat.  The mat is just large enough to holds on to the sea-plane's floats, the plane is now being tow along side.  A crane puts the plane back onboard.

A visiting space vehicle can use similar methods.  Navigate to near the spinning donuts' docking area; via magnetic coupling or actual nylon tow strip-rope, it is pulled to the final position then locked.  Once docked, the spinning donuts is needs to be re-balanced.  So best to have two docks on opposite side of the spinning donuts both with the same number of bays (more money).  Each bay has a moving mass to balance the angular momentum of the bay's load (and more money still).  Done, theoretically; just another theoretic solution among many.  Selecting right theoretical solution and making it real means more money.

We will have a long-stay space station with capability similar to Space 2001, someday.  Sooner the better.  Otherwise, the human species' destiny is extinction.

[DougSpindler]

We will have a long-stay space station with capability similar to Space 2001, someday.  Sooner the better.  Otherwise, the human species' destiny is extinction.

I don't thinks so.  Did you look at the resources required and the cost?

[PlainName]

I would think cost and structural issues are the biggest problem.

The NASA link seemed to suggest that everyday practicality might trump that. Just going for a spacewalk would be a much more serious undertaking than now, so outside maintenance would be frowned upon so things get more complex. Also, if you've got this spinning thing and need to do maintenance then you probably need to not have it spinning, which means winding it down. If the craft is one that has a spinning living part and non-spinning other, or one that resembles a long pole with the axis in the middle, then stopping it spinning is a big problem. As might be getting it going again.

For astronauts that need to be in space then zero-grav is no doubt fine. For the rich tourists, maybe having artificial gravity is not a requirement - you go there because it's different, not the same. As a for instance, I remember going to France back before we joined the EU, and it was like visiting a foreign country. Hell, it WAS a foreign country . Passports, weird money, etc. Then we joined the EU and going to France was almost like nipping down the shops (albeit a bit further), so the sense of having gone somewhere was much less.

[wraper]

SpaceX really is not revolutionary but some incremental improvement.  It reduce cost in large part by good execution instead of revolutionary technology.  I would have imagine they mind their operations like a hawk to ensure good execution.

Given Musk's Tesla model3 experience, I expected his operation(s) to be smoother than it seem so far.  The virus lock downs and panic that happened in the last couple of years may have been a factor.

SpaceX is a good thing for the industry.  I would not like to see it fail.

Really going to ignore the self-landing reusable booster thing as "not revolutionary"? The only other "reusable" rocketry was the space shuttle and that really isn't reusable in a meaningful way by both in time and cost.

The idea isn't revolutionary at all. SpaceX is just the most successful at making it work.

Reusable spacecraft go all the way back to 1962, when the reusable  launched from a reusable B-52 and entered space, earning astronaut wings. An event that was repeated 12 times during the 199 flights of the program.

One of the gemini capsules flew twice.

You already mentioned the space shuttle.

There's the X-37, which you don't hear much about because it's military. They have two vehicles that have flown six long-term missions (the sixth is still in progress) since 2010.

Northrup Gumman Pegasus has put smaller payloads into low orbit from reusable carrier aircraft starting in 1990.

And of course Blue Origin and Virgin Galactic have both flown reusable vehicles now.

Idea by itself is worth nothing. X-15, BE's New Shephard and Virgin galactic's SpaceShipTwo are not even close to orbital class systems. Getting into an orbit requires more than an order of magnitude more energy than peeking beyond Karman line for a few minutes. It's like comparing a toy RC car to a truck. Space shuttle and X37 did not return boosters, not to say it would be cheaper to not reuse Space shuttle at all.

[Nusa]

SpaceX really is not revolutionary but some incremental improvement.  It reduce cost in large part by good execution instead of revolutionary technology.  I would have imagine they mind their operations like a hawk to ensure good execution.

Given Musk's Tesla model3 experience, I expected his operation(s) to be smoother than it seem so far.  The virus lock downs and panic that happened in the last couple of years may have been a factor.

SpaceX is a good thing for the industry.  I would not like to see it fail.

Really going to ignore the self-landing reusable booster thing as "not revolutionary"? The only other "reusable" rocketry was the space shuttle and that really isn't reusable in a meaningful way by both in time and cost.

The idea isn't revolutionary at all. SpaceX is just the most successful at making it work.

Reusable spacecraft go all the way back to 1962, when the reusable  launched from a reusable B-52 and entered space, earning astronaut wings. An event that was repeated 12 times during the 199 flights of the program.

One of the gemini capsules flew twice.

You already mentioned the space shuttle.

There's the X-37, which you don't hear much about because it's military. They have two vehicles that have flown six long-term missions (the sixth is still in progress) since 2010.

Northrup Gumman Pegasus has put smaller payloads into low orbit from reusable carrier aircraft starting in 1990.

And of course Blue Origin and Virgin Galactic have both flown reusable vehicles now.

Idea by itself is worth nothing. X-15, BE's New Shephard and Virgin galactic's SpaceShipTwo are not even close to orbital class systems. Getting into an orbit requires more than an order of magnitude more energy than peeking beyond Karman line for a few minutes. It's like comparing a toy RC car to a truck. Space shuttle and X37 did not return boosters, not to say it would be cheaper to not reuse Space shuttle at all.

I was responding to the claim about "reusable rocketry", which he said included the space shuttle. I don't disagree with you about what's orbital class, but that wasn't part of the claim. Of course, some of those systems have orbital capability in mind when not in tourist mode...Virgin's WhiteKnightTwo can haul a 17,000 kg rocket to 50,000 feet for launch, which is effectively a reusable first stage.

Fact checks:
One of the X37 launches was on a Falcon 9.
Shuttle solid rocket boosters had parachute landings in the ocean and were routinely recovered and refurbished for future flights.

[wraper]

Shuttle solid rocket boosters had parachute landings in the ocean and were routinely recovered and refurbished for future flights.

Calling that refurbishing is not quite accurate though. More like reusing some old components. They basically took an empty shell, then completely disassembled it and reused parts after refurbishing those. Probably cheaper just to build a new shell. In other words, if you reuse something like 20% of the complete thing with a huge amount of work involved to do so, does it even count as refurbishing? On the outer part of the segment level sure they were reused. But on the level of a whole SRB barely so.

[Rick Law]

We will have a long-stay space station with capability similar to Space 2001, someday.  Sooner the better.  Otherwise, the human species' destiny is extinction.

I don't thinks so.  Did you look at the resources required and the cost?

When it comes to survival, cost and resource is of little concern.

Estimate is 500 million years to 1.5 billion years from now, the Sun will go into red giant phase.  People will do a lot of things when their own demise is at hand.  If we do not further space technology enough to migrate between planets or shift our planet's orbit, we are literally cooked.  That red giant phase is the upper limit for our existence if we do not have interplanetary level of space technology.

Yeah, 500 million years is a long time from now, but having a lot of time to do nothing will still result in get nothing done.

NM4, last visited in 2004.  Next visit will be a near-miss April 13, 2029.   A 350 meter (approx) diameter tiny thing but could kill millions depending on where it hits.  We think it will be a near-miss right now.  It will near-miss, go around, and near-miss us again 2036 on its way out.  Passing close enough to be beneath the geo-sync orbit.  But what if we are wrong?  What technology would we have by then to do anything at all if as it get closer, we realize it isn't going to be a near miss but a direct hit?  If we take a long time doing nothing, we will still have nothing.  And we are statistically certain a bigger one is on its way, we just haven't seen it yet.

So I am very much in favor of advancing space technology quickly.  I know just earlier I said I like to make space launch expensive so we don't have a lot of junk in low earth orbit.  But there is a difference between advancing science that benefit the entire species vs building a business while in the process leaving dangerous stuff for years to come.

I know even if we survive the red-giant phase, eventually the Sun will go dark. We'll need to solve it one step at a time.

Edit: Added the paragraph on NM4 (and fixed wording a couple of times in that paragraph)

[jonovid]

if one could carry water to the moon, maybe we could make loona concrete,
maybe we could have a loona construction site. 

[DougSpindler]

We will have a long-stay space station with capability similar to Space 2001, someday.  Sooner the better.  Otherwise, the human species' destiny is extinction.

I don't thinks so.  Did you look at the resources required and the cost?

When it comes to survival, cost and resource is of little concern.

Estimate is 500 million years to 1.5 billion years from now, the Sun will go into red giant phase.  People will do a lot of things when their own demise is at hand.  If we do not further space technology enough to migrate between planets or shift our planet's orbit, we are literally cooked.  That red giant phase is the upper limit for our existence if we do not have interplanetary level of space technology.

Yeah, 500 million years is a long time from now, but having a lot of time to do nothing will still result in get nothing done.

NM4, last visited in 2004.  Next visit will be a near-miss April 13, 2029.   A 350 meter (approx) diameter tiny thing but could kill millions depending on where it hits.  We think it will be a near-miss right now.  It will near-miss, go around, and near-miss us again 2036 on its way out.  Passing close enough to be beneath the geo-sync orbit.  But what if we are wrong?  What technology would we have by then to do anything at all if as it get closer, we realize it isn't going to be a near miss but a direct hit?  If we take a long time doing nothing, we will still have nothing.  And we are statistically certain a bigger one is on its way, we just haven't seen it yet.

So I am very much in favor of advancing space technology quickly.  I know just earlier I said I like to make space launch expensive so we don't have a lot of junk in low earth orbit.  But there is a difference between advancing science that benefit the entire species vs building a business while in the process leaving dangerous stuff for years to come.

I know even if we survive the red-giant phase, eventually the Sun will go dark. We'll need to solve it one step at a time.

Edit: Added the paragraph on NM4 (and fixed wording a couple of times in that paragraph)

If you are in favor if it, you can pay for it with your money and not mine.

[EEVblog]

We will have a long-stay space station with capability similar to Space 2001, someday.  Sooner the better.  Otherwise, the human species' destiny is extinction.

Space colonies, moon colonies, or Mars colonies will not save earth from extinction. They will all eventually die out without resources from earth.

[AVGresponding]

We will have a long-stay space station with capability similar to Space 2001, someday.  Sooner the better.  Otherwise, the human species' destiny is extinction.

Space colonies, moon colonies, or Mars colonies will not save earth from extinction. They will all eventually die out without resources from earth.

The asteroid belt between Mars and Jupiter has plenty of resources, though obviously there are some challenges in exploiting it...

The Kuiper belt has even more resources, but it's even further out, so even harder to exploit, but arguably easier than mining from any planet, as you'd not need to boost anything you mined up to a planetary escape velocity.

[PlainName]

"You can't go down the shops without first stepping outside your door."

Once we're space mobile, where would we go? Another star system doesn't really seem practical because it would take so long to get there and then none of the planets might be suitable. And we'd get the same issue there, too, eventually. So perhaps the solution is to adapt to a red giant, becoming independent of Earth. Or any planet for that matter - by that time surely we could figure a way to create an off-planet habitat. The many asteroids and outer planets could provide resources once we have the technology to get them.

But eventually we would still be done for as the red giant goes nova or whatever.

And... I can't see us moving on as if we were a family moving out to the suburbs. Humanity just isn't going pack itself into crates and move en block somewhere else. What is much more likely to happen is like in the American west where a few adventurers go off and do adventures then kind of settle in a likely area and have kids. If they're the lucky ones they'll be Adam and Eve (assuming wokeness hasn't done for them first), and the vast majority of everyone else will just die off.

That looks to me like saving the species is going to be more accidental than a coherent world-wide party, and people like Musk, Bezos, Branson, etc are going to be our saviours. Not because they are planning to be but because they are out there either doing or providing the adventures.