SpinLaunch: General Company and Development Updates and Discussions

[gmbnz]

I think their intended market is bulk commodities, such as propellant and consumables for humans.

My understanding is that they don't intend the spin launch to get a payload up to orbital speed or even close to it.  That is not feasible because of the atmospheric resistance.

Instead, they intend this as a sort of first stage.  The problem I have is that I think their second stage will be very expensive because it has to handle all the g forces (not nearly as much as for an orbital spin launch, but still a lot) and all the aerodynamic forces and still provide quite a bit of delta-V.  I think they'll be able to make it work, but it will just be too expensive.

That makes a bit more sense, although we're still a way from where that service is needed. Hopefully not for long!

Even if the muzzle velocity is 3-4 km/s there's still an awful lot of delta-V to make up with what will have to be an incredibly robust (i.e. poor mass fraction) stage or two. It's one of those things where I personally just can't see the added complexity being better than a 'simple' reusable first stage.

Immerse your electronics in liquid carbon dioxide.

That's a neat idea, although I was more thinking of the internals; oscillators, IMU, batteries, GPS, etc will still struggle with those high G forces, except for the high end / pricey ones.

I would be intrigued to see a projected trajectory for a mission; is it better to go straight up or to try and get some tangential velocity at the cost of more atmosphere?

[edzieba]

MEMS devices are the only ones that really have difficulty with very high accelerations, and there are commodity solid-state alternatives available (I think the single-chip silicon-photonic ring-laser-gyros might even be on the commercial market now?).

[su27k]

Huge amount of details in this new article, pretty much all the questions answered, more or less: Inside SpinLaunch, the Space Industry’s Best Kept Secret

[Stan-1967]

Nice article.  It lays bare that Spinlaunch is facing head on the engineering challenges that are obvious, and they were able to convince investors with qualified people doing due diligence for them.  More details on when they think they will be ready to launch would be nice.

[ChrisWilson68]

Huge amount of details in this new article, pretty much all the questions answered, more or less: Inside SpinLaunch, the Space Industry’s Best Kept Secret

It's nice to see more details.  Unfortunately, nothing in the article makes their case look more plausible.  I continue to believe that, if they can get enough funding, eventually they will be able to send payloads to orbit, but that it will not be anywhere close to economically viable.

I cringed at many things in the article.  The most cringe-worthy was this quote:

Yaney has heard these criticisms before. He happens to see a lack of industry experience as an asset. “We’ve been putting together a team of engineers who, for the most part, are too young to say SpinLaunch couldn't work,” he says. “They’re full of too much energy and excitement to find out what's going to happen.”

It's great to have fresh graduates, but experience is also important.  Disparaging all experience is not a recipe for success.

The article says payloads will need to survive 10,000g sustained acceleration.  The spin-up time is an hour, so they'll sustain much of that for many minutes.

But their payload size is only 100kg and it will cost $500,000 per launch.

They claim to only be interested in customers who want to launch large constellations.

So, 100 launches at $500,000 per launch is 10,000kg for $50 million, even if they hit their optimistic projections.  That compares unfavorably to what Falcon 9 can already do with rideshare, and the customers have to drastically harden their satellites to withstand 10,000g.

This is delusional.

[ChrisWilson68]

Also, the article says the centrifuge will accelerate the rocket and payload to 5,000 miles per hour.  That's 2.2 kps.  LEO orbital speed is at least 6.9 kps.  That means even ignoring all aerodynamic and gravity loses and cosine loses from the angle, they still need at least 4.7 kps out of the rocket they're throwing up there.  That's a very significant amount of delta-V.  And it needs to come from a rocket that can survive 10,000g.  And cost under $500,000 -- well under because that $500,000 per launch also has to pay for the centrifuge operation and all other overhead.

This seems wildly implausible to me.

In summary, I think they're wildly optimistic in the price they're setting.  And, even if they could do it for that price, it's not a price that would be appealing to any customer.

[Stan-1967]

I would pay money to see this thing launch.  I'll bring the best ear protection money can buy.  I think it i going to look like an ear splitting, eye blinding streaking mass of ball lightning shooting into the sky.  They should build the facility to look like a Star Wars Turbo laser facility.  The Hawaiin's were correct to not want this thing anywhere near their beautiful islands.

[ChrisWilson68]

I would pay money to see this thing launch.  I'll bring the best ear protection money can buy.  I think it i going to look like an ear splitting, eye blinding streaking mass of ball lightning shooting into the sky.  They should build the facility to look like a Star Wars Turbo laser facility.  The Hawaiin's were correct to not want this thing anywhere near their beautiful islands.

I would also pay money to see it in action.

Unfortunately, I think it's very unlikely it will ever make an orbital launch attempt.  They'll spend a bunch of money but they run out and be unable to raise more, like so many other launch companies in the past.

[ParabolicSnark]

Yaney has heard these criticisms before. He happens to see a lack of industry experience as an asset. “We’ve been putting together a team of engineers who, for the most part, are too young to say SpinLaunch couldn't work,” he says. “They’re full of too much energy and excitement to find out what's going to happen.”

It's great to have fresh graduates, but experience is also important.  Disparaging all experience is not a recipe for success.

Fresh graduates are eager and moldable into engineers that can specialize in the specific project details that are needed. However, it's critical that they have technical mentorship and are supported by an experienced senior team that can guide key decisions so they get started down the right path and dodge all the pitfalls along the way that lead to expensive losses and massive delays.

An example of this would be their work at Spaceport America. A birdie tells me a large supply of steel was being delivered to a test site, but when the delivery driver saw the only access as a dirt road, they dropped it off right there and left SpinLaunch to figure out how to get it the rest of the way. That's not something fresh-out's learn to identify - people who've been around the block can spot that issue coming before it becomes a problem. (Apparently SpinLaunch is now in the business of paving roads.)

One of their targets was David Wrenn, a junior at San Diego State University. He took a leave of absence from college and flew out to San Francisco to join SpinLaunch, where he now works as a senior mechanical engineer.

Either that's the over-title of the year, or SpinLaunch's senior technical team is grossly under-qualified.

So, 100 launches at $500,000 per launch is 10,000kg for $50 million, even if they hit their optimistic projections.  That compares unfavorably to what Falcon 9 can already do with rideshare, and the customers have to drastically harden their satellites to withstand 10,000g.

I've never been a fan of comparing economics (at least $/kg) of small sat launch vehicles to larger launch vehicles, even ride shares, because it's inherently a flawed comparison. A ride share is no where close to a dedicated vehicle and that perk comes with substantial costs.

In addition to the 10,000 G's, there's almost certainly going to be a large sinusoidal vibration load at the revolution rate of the centrifuge that will further drive payload/vehicle structural requirements. Of course, then there's the shock when it hits atmosphere....then the aerodynamic buffetting loads...

5 launches a day is comical, especially as they've revealed the pump down time (not including spin-up time) as 1 hour long. Mechanical integration of the vehicle to the centrifuge is not going to be a quick operation without the amount of verification and checkouts they're going to want to do (as the consequence of not doing is a possible failed/delayed release inside the chamber).

...an exit port in the centrifuge will open for a fraction of a second, sending the rocket shooting out.

Methinks the door is also going to be a substantial technical hurdle. Based on their graphic, that door is probably around 5m wide, holding back 14.7 psig of pressure. That's going to be a big chunk of steel. Back of the napkin calculations put it at about 6" thick solid steel, weighing about 25 ton. Now, that's a flat plate and I'm sure you could dome it and make it a lot more mass efficient, but even if you get to 10% of that estimate, you're moving 2.5 ton in a fraction of a second...

As the iPhone demonstration attests, electronic components can survive the extreme forces during acceleration, though some more delicate electronics will need slight modifications.

Aren't iPhone's entirely solid state devices? I don't see that mapping well to satellite payloads.

Hampton and about two dozen other employees have lived near the spaceport in a makeshift company town made of shipping containers.

And people say open-office workspace are bad. Living in a shipping container...in the desert... But at least it has a virtual reality room 

[ParabolicSnark]

5 launches a day is comical, especially as they've revealed the pump down time (not including spin-up time) as 1 hour long. Mechanical integration of the vehicle to the centrifuge is not going to be a quick operation without the amount of verification and checkouts they're going to want to do (as the consequence of not doing is a possible failed/delayed release inside the chamber).

...an exit port in the centrifuge will open for a fraction of a second, sending the rocket shooting out.

Methinks the door is also going to be a substantial technical hurdle. Based on their graphic, that door is probably around 5m wide, holding back 14.7 psig of pressure. That's going to be a big chunk of steel. Back of the napkin calculations put it at about 6" thick solid steel, weighing about 25 ton. Now, that's a flat plate and I'm sure you could dome it and make it a lot more mass efficient, but even if you get to 10% of that estimate, you're moving 2.5 ton in a fraction of a second...

US Patent WO2019164472A1 provides more details on the timing of the operation. Vacuum pump down is 1 hour as shown in the article. Spin-up is 30 minutes. Release is 1-3 msec.

This patent also includes some calculations and plots showing release velocity, mach number, and flight angle, though it appears to be for a slightly different configuration (43 kg payload, 2,000 kg vehicle).

It offers 2 sentences about the door:

In various embodiments, the exit port 115 may comprise a fast-actuating door or shutter. In other embodiments, the exit port 115 may comprise one or more sheets of a polymeric material such as Mylar which may be pierced by the launch vehicle 105 upon launch.

So potentially add the shock of punching through the door at 2.8 km/s to the list of environments.

[ParabolicSnark]

Nothings been said in this article or patent about the coupling device that is going to release in 1-3 msec. No mechanical linkage is going to be able to release that fast with two possible exceptions coming to mind:
1) pyro-separated bolts (yet another shock load)
2) electromagnets that can be turned off to release

A 2,000 kg vehicle at 2.8 km/s at a 50m radius pulls 71 million lbf on the centrifuge. I can't begin to think of the magnet that does that (I'm not big on E&M), but for a bolted joint using 220 ksi fasteners, you'd need a tensile area of 323 in^2. That's a 20" diameter bolt. You could use ~100x 2" diameter bolts, but then you have to make sure all bolts fail exactly at the right time or bad new bears.

[john smith 19]

I would pay money to see this thing launch.  I'll bring the best ear protection money can buy.  I think it i going to look like an ear splitting, eye blinding streaking mass of ball lightning shooting into the sky.  They should build the facility to look like a Star Wars Turbo laser facility.  The Hawaiin's were correct to not want this thing anywhere near their beautiful islands.

Indeed.

Outside of Gerald Bulls' HARP work (which IIRC was run on Hawaii) the nearest thing to this would have been the test firings of the Sprint ABM, which broke M1 at around 30m above its launch silo.

This puppy will be considerably more impressive.

[Stan-1967]

It's been a few house since I read the article & I'm still lollzing that my biggest impression is that the VC angel investors came across as the stable voice of reason more than the company founders. 

[Toast]

Nothings been said in this article or patent about the coupling device that is going to release in 1-3 msec. No mechanical linkage is going to be able to release that fast with two possible exceptions coming to mind:
1) pyro-separated bolts (yet another shock load)
2) electromagnets that can be turned off to release

A 2,000 kg vehicle at 2.8 km/s at a 50m radius pulls 71 million lbf on the centrifuge. I can't begin to think of the magnet that does that (I'm not big on E&M), but for a bolted joint using 220 ksi fasteners, you'd need a tensile area of 323 in^2. That's a 20" diameter bolt. You could use ~100x 2" diameter bolts, but then you have to make sure all bolts fail exactly at the right time or bad new bears.

0.5 x 2,000 kg x (2,800 m/s)² = 7.84 Gigajoules of kinetic energy.
So if the timing's off and the vehicle misses the door...bad news bears indeed.

[john smith 19]

I've never been a fan of comparing economics (at least $/kg) of small sat launch vehicles to larger launch vehicles, even ride shares, because it's inherently a flawed comparison. A ride share is no where close to a dedicated vehicle and that perk comes with substantial costs.

Good point. The Classic benefits are the bespoke orbit and time you want.

OTOH most LV's only need regular hardening, not gun launch grade.

5 launches a day is comical, especially as they've revealed the pump down time (not including spin-up time) as 1 hour long. Mechanical integration of the vehicle to the centrifuge is not going to be a quick operation without the amount of verification and checkouts they're going to want to do (as the consequence of not doing is a possible failed/delayed release inside the chamber).

This problem was faced by the semiconductor industry decades ago. Creating and preserving UHV is a massive PITA when even the oils from a fingerprint can put you over the pressure limit.

The solution is to clean, pump down and bake out the bulk of the vacumm chamber then access it from then on through much smaller volume airlocks. These processes are referred to as "load lock" techniques.

...an exit port in the centrifuge will open for a fraction of a second, sending the rocket shooting out.

Methinks the door is also going to be a substantial technical hurdle. Based on their graphic, that door is probably around 5m wide, holding back 14.7 psig of pressure. That's going to be a big chunk of steel. Back of the napkin calculations put it at about 6" thick solid steel, weighing about 25 ton. Now, that's a flat plate and I'm sure you could dome it and make it a lot more mass efficient, but even if you get to 10% of that estimate, you're moving 2.5 ton in a fraction of a second...

I thought about this  Isn't the question about how much deformation the door has to withstand?

I learned recently that a standard sheet of aluminum foil can resist 1 atm.

My instinct is that most of the time a large heavy door will resist atmospheric pressure most of the time.

During the launch the exit will be covered by a much lighter door. Something more like a film on a roller dropping downward, possibly using electromagnetic carriers on either side of the opening and falling downward (so gravity is on your side).

I wonder who the anonymous former Spinlaunch employee was that Wired spoke to.

[Stan-1967]

Anyone have thoughts on how the rotating tether/arm will have to be very quickly brought into a new balance point when the vehicle detaches?  I can't see ejecting it like a counterweight, so would that counterweight be liquid filled so that at the same moment the vehicle leaves one end of the arm, valves open that would quickly empty the liquid content needed to re-balance the system?

[ParabolicSnark]

0.5 x 2,000 kg x (2,800 m/s)² = 7.84 Gigajoules of kinetic energy.
So if the timing's off and the vehicle misses the door...bad news bears indeed.

For reference, the TNT equivalent is 1.9 tons. That's about 4 Tomahawk cruise missiles (conventional warhead).

[ChrisWilson68]

Anyone have thoughts on how the rotating tether/arm will have to be very quickly brought into a new balance point when the vehicle detaches?  I can't see ejecting it like a counterweight, so would that counterweight be liquid filled so that at the same moment the vehicle leaves one end of the arm, valves open that would quickly empty the liquid content needed to re-balance the system?

From the article:

According to patents filed by the company, a counterbalance spinning opposite the rocket gets released at the same time, preventing the tether from becoming unbalanced and vibrating into oblivion.

[ParabolicSnark]

Anyone have thoughts on how the rotating tether/arm will have to be very quickly brought into a new balance point when the vehicle detaches?  I can't see ejecting it like a counterweight, so would that counterweight be liquid filled so that at the same moment the vehicle leaves one end of the arm, valves open that would quickly empty the liquid content needed to re-balance the system?

The patent I posted shows the counterweight (labeled 135) detaching in Figure 5B and 5C. No mention of what happens when they release that...

Edit: added label reference.

[ChrisWilson68]

Anyone have thoughts on how the rotating tether/arm will have to be very quickly brought into a new balance point when the vehicle detaches?  I can't see ejecting it like a counterweight, so would that counterweight be liquid filled so that at the same moment the vehicle leaves one end of the arm, valves open that would quickly empty the liquid content needed to re-balance the system?

The patent I posted shows the counterweight (labeled 135) detaching in Figure 5B and 5C. No mention of what happens when they release that...

It's a strange omission.  That counterweight will have the same 1.9 tons of TNT energy to dissipate.  It's an obvious, big issue so they must have some thoughts about it.