Not sure if anyone else has mentioned this before, but what happens when the unleashed payload collides with the self generated sonic boom that it is already travelling outwards from the launch site? Surely there is a sweet spot where the departing shock wave is so dense, it will form a 'brick wall' ahead of the departing launch vehicle? Or are we launching from the Moon to avoid claims for broken windows, 50 miles away?
And even if the launch vehicle has the strength of a bowling ball, the induced spin at "unleash", will turn all but the very center of the payload into mincemeat?
I think this is like Thorium reactors, there are a number of technical issues which still need to be solved. I think like Thorium reactors, Theranos, Hyperloop, and Nikola Trucks until they run out of money they will keep saying it can be done. Then once they’ve burned through all of the money the employees will come clean saying we knew all along it was never going to work.
I would like to remind everyone that GPS guided artillery shells experience accelerations on the order of 16000g. If thats typical in use, then you can guarantee they can withstand more than that for reliability.
If we can build electronics to withstand being blasted out of a short 155mm artillery barrel, then Spinlaunch doesn't seem like so much of a stretch.
It is not just technical problems. It is just a rather stupid idea: The centrifugal force is impractical high and would require a sattelite that gets way to heavy. It's close to the point of only usefull for things like steel balls. If at all the idea of a more classical acceleration is practical for the first part. The idea behind it is that at low speed a rocket is rather inefficient. At an allready high speed it gets OK. So statrting at something like the speed of sound could reduce the size of rocket somewhat.
The biggest potential SpinLaunch has is StarLink. StarLink if fully implemented will have 30,000 satellites each with a plan service life of under 5 years due to it's low orbit of just under 350 miles. Do the math, that is >16 launches a day. That rate makes it a mass-produced satellite. As such, it can have high-g tolerance built in at design and spreading the cost over many satellites. The StarLink low orbit is also a plus for SpinLaunch. Whereas, other satellite are more likely one-off's (or limited copies) making reinforcement (design + test) cost much higher on a per-satellite basis, and the low 350 miles may only work for some of those other limit copies satellites.
My opinion is: SpinLaunch's viability lies with the viability of StarLink and it's ability to add this payload reinforcement cost while maintaining cost-viable. If StarLink fizzles, SpinLaunch is toasted.
It is not just technical problems. It is just a rather stupid idea: The centrifugal force is impractical high and would require a sattelite that gets way to heavy. It's close to the point of only usefull for things like steel balls. If at all the idea of a more classical acceleration is practical for the first part. The idea behind it is that at low speed a rocket is rather inefficient. At an allready high speed it gets OK. So statrting at something like the speed of sound could reduce the size of rocket somewhat.Satellites need to be built with acceleration in mind however it's not nearly as you say. Usual SMD circuit board with no heavy components will survive just fine if it has proper support. SMD parts will not fly off from PCB. For example take 0603 resistor which weights about 2 mg, with 11000G it will be around 220 N of force on the part (equal to 22 grams at 1G). You need way more force to rip it from PCB.
Many saterlites want relatively large area solar cell for power, that need a kind of rather delicate folding mechanism.
The biggest potential SpinLaunch has is StarLink. ... ... ...
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My opinion is: SpinLaunch's viability lies with the viability of StarLink and it's ability to add this payload reinforcement cost while maintaining cost-viable. If StarLink fizzles, SpinLaunch is toasted.It would totally suck for Starlink. These are complicated satellites not that easy to reinforce and are not small at all. How many it could launch even without considering weight increase? Answer is zero because Starlink satellite has larger mass than max lift capacity of Spinlaunch. And it's without considering V2 satellites are much larger and need Starship to be launched viably. But even if it could lift one, a second stage spent for a single Starlink satellite, really? Even if it would theoretically make 16 launches a day, it still would be barely faster than current launch cadence on Falcon 9. In July alone, 251 Starlink satellites were launched on 5 rockets.
The biggest potential SpinLaunch has is StarLink. ... ... ...
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My opinion is: SpinLaunch's viability lies with the viability of StarLink and it's ability to add this payload reinforcement cost while maintaining cost-viable. If StarLink fizzles, SpinLaunch is toasted.It would totally suck for Starlink. These are complicated satellites not that easy to reinforce and are not small at all. How many it could launch even without considering weight increase? Answer is zero because Starlink satellite has larger mass than max lift capacity of Spinlaunch. And it's without considering V2 satellites are much larger and need Starship to be launched viably. But even if it could lift one, a second stage spent for a single Starlink satellite, really? Even if it would theoretically make 16 launches a day, it still would be barely faster than current launch cadence on Falcon 9. In July alone, 251 Starlink satellites were launched on 5 rockets.
Both have business model that is yet unproven when scaled. Technology may work, but profit generating? A big "may be" for both. The two may come to some middle ground. 16 launches a day is a lot. Savings there should help Starlink and for Spinlaunch a huge customer... Then again, may be it is another case of: "If you tie the two rocks together, perhaps they will now float..."
Starlink is certainly at a better place. They have proven their technology, and government subsidies from various un-wired (or inadequately-wired) countries is a good possibly. That matter is still size of the $ sign. Whereas, if SpinLaunch doesn't do Starlink, missing the highest volume launch-user will be a deadly blow.
When it comes to railguns the US has gave up after 15 years and half a billion dollars.
https://taskandpurpose.com/news/navy-electromagnetic-railgun-dead/
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What would the centripetal g force on the payload be compared with simply shooting it out of a very large gun pointed skyward?
In comparing one force verses another acting on the same mass, since f=ma are true for both cases (Newton's second law of motion), mass cancels out leaving you just comparing acceleration.
For the object orbiting around a center, V is the linear velocity while orbiting, and it equals the velocity at release:
Centripetal /centrifugal acceleration is a = V2/R, here R is the distance to the center of rotation.
For the object being shot out of a barrel (or rail of a rail-gun), V is the exit velocity of the object when leaving the barrel
Shooting out of a gun is difficult to say since acceleration by gas-explosion is not constant while in the barrel. Let's assume it is constant acceleration like you can do with a linear motor catapult or rail-gun. With such assumption, while in the barrel, then:
Linear constant acceleration would be a = V2/2L, here L is the length of the gun barrel.
So, if your gun is half the radius of the centrifuge, your acceleration is the same and thus the force are the same. Of course, radius is just 1/2 the width (diameter) of the centrifuge.
I don't know about these SpinLaunch folks... I think building a rail-gun 25 meters in length would be easier than building a centrifuge 100 meters in diameter, and a linear rail is far easier to aim.
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What savings??? It's literally more expensive. There are (potential) savings if you want to launch a small payload standalone. If the same payload can be combined to fill a large rocket, there are no savings. Also it's a pretty weird idea Spacex would suddenly use a 3rd party launch service when they are the largest launch provider in the world themselves. Not to say launch on reused boosters, Oldest of which have flown up to 13 times already.
I say let's see if enough money is thrown at Spinlaunch if they can do it.
The 300m railgun mentioned above would have to apply 1.8GW to a 200kg projectile to reach 2222m/s. With typical efficiencies being 10-50% that means a power source capable of somewhere between 3.6GW and 18GW, and energy storage between 1GJ and 5GJ. Not trivial.
Making the railgun longer reduces the power requirement, but the energy storage remains (or more likely gets worse).
QuoteI say let's see if enough money is thrown at Spinlaunch if they can do it.
Are you sure you're speaking for yourself? Most of your posts are pushing the "it can't work" line.
We seem to have taught a generation All Things Are Possible If You Only Believe. Which I think stems from
Mark 9:23 — "All things are possible for the one who believes.”
I'm not a physicist, only took a couple of classes in college. Sure looks to me like they intended on breaking several laws of physics and people who know more about physics see to agree with me. And you have Thunderf00t who knows more about this stuff, who pointed out several many other issues.
We've had spin launchers for decades, called clay target launchers or skeet throwers. If it would have been easy and cost effective someone would have built a Spinlancher years ago, but they didn't.
You have people like Elizabeth Holmes who believe anything is possible if enough money is thrown at it and you ignore the science and what the top researchers in that subject area tell you.
If someone has billions to spend on it, let them, it employee people. I suspect several of the people at Spinlaunch know it can't be done and are happy to take a paycheck from some money guy who never took or failed a physics class.
We seem to have taught a generation All Things Are Possible If You Only Believe. Which I think stems from
Mark 9:23 — "All things are possible for the one who believes.”
I'm not a physicist, only took a couple of classes in college. Sure looks to me like they intended on breaking several laws of physics and people who know more about physics see to agree with me. And you have Thunderf00t who knows more about this stuff, who pointed out several many other issues.
We've had spin launchers for decades, called clay target launchers or skeet throwers. If it would have been easy and cost effective someone would have built a Spinlancher years ago, but they didn't.
You have people like Elizabeth Holmes who believe anything is possible if enough money is thrown at it and you ignore the science and what the top researchers in that subject area tell you.
If someone has billions to spend on it, let them, it employee people. I suspect several of the people at Spinlaunch know it can't be done and are happy to take a paycheck from some money guy who never took or failed a physics class.
We seem to have taught a generation All Things Are Possible If You Only Believe. Which I think stems from
Mark 9:23 — "All things are possible for the one who believes.”It does not break any laws of physics. Actually its principle of operation is pretty dumb. The questionable part is practicality, not if it can be built as such.