Spinlaunch on the Moon

[lamontagne]

The orbital Spinlaunch concept seems nicely aligned to be used on the Moon as a launch system for mass payloads with similar performance to a mass driver but with much lower technological requirements.

-The exit velocity, at 2200 m/s, is correct for orbital insertion.
-You don't need the vacuum chamber on the Moon.
-You don't need a track.
-The arm stores the energy, no inductive or capacitive banks required.
-The launch vehicle can include a control system+rocket for circularization of the orbit.
-High repeatability.  you could launch every few hours, and eventually have a large number of these for very large mass output.

https://www.spinlaunch.com/

The overall mass of a complete system including solar array, tower, motor, drive, handling system should fit on a single Starship with place to spare.
So a bit like the original Landis tower or Zubrin launcher, but with a short arm rather than a long tether.

Too good to be true?  Have I missed something?
What might be the highest 'g' a launcher might survive and still operate as a rocket after?

[edzieba]

What might be the highest 'g' a launcher might survive and still operate as a rocket after?

Very high indeed. From the artillery world, rocket-boosted and base-bleed (rocket with thrust below shell drag) guided rounds work just fine - at least 16,500g design target - meaning real-world rocket propellants and electronics are not the limiting factor. As Spinlaunch themselves have found (and are tackling as their main task at the moment) small moving parts like reaction wheels and solar array deployment mechanisms are the limiting factor, but not insurmountable.

[lamontagne]

An old lunar sling launch spreadsheet modified for Spinlaunch.
Could use a 75 HP motor and a VFD for power.  And you can use the braking of a spinlaunch to accelerate a second spinlaunch, minus the various system losses, the only energy 'lost' would be the kinetic energy of the launcher/mass payload.
wonder if I need chemical propulsion for orbital insertion, or if I can get away with a cold thruster?

[stilrz]

Elon Musk has specifically said Spinlaunch on the moon is a great idea. Lots of synergy once starship + booster can land on earth. 

So my simple idea is that to get to Mars you need a space station. In my view building a space is a lot easier if you already have a space station. 1) So build a starship based station at L1 between the earth and the moon. 2) install a spinlaunch system on moon 2) launch regolith, water and solid co2 to L1. 3) Build structure with iron/titanium from moon materials 4) build structures to hold mass to shield a spacestation at L1   5) Launch space station from LEO  AND launch radiation shielding from L1 at same time 6) join the two on route.  I would really want 3 meters of water or regolith between the starship and space to reduce cosmic ( and solar) radiation damage. Oh space station will have to spin also :-)
 

Btw first human Mars trip will contain at least these starship based elements: 2 habitat modules complete, 2+ fuel reserves 1 lander  and 1 supply ship. 

[lamontagne]

Elon Musk has specifically said Spinlaunch on the moon is a great idea. Lots of synergy once starship + booster can land on earth. 

So my simple idea is that to get to Mars you need a space station. In my view building a space is a lot easier if you already have a space station. 1) So build a starship based station at L1 between the earth and the moon. 2) install a spinlaunch system on moon 2) launch regolith, water and solid co2 to L1. 3) Build structure with iron/titanium from moon materials 4) build structures to hold mass to shield a spacestation at L1   5) Launch space station from LEO  AND launch radiation shielding from L1 at same time 6) join the two on route.  I would really want 3 meters of water or regolith between the starship and space to reduce cosmic ( and solar) radiation damage. Oh space station will have to spin also :-)
 

Btw first human Mars trip will contain at least these starship based elements: 2 habitat modules complete, 2+ fuel reserves 1 lander  and 1 supply ship.

Interesting.  did Musk say/write Spinlaunch or liner accelerator?  There is an x post on a linear accelerator.  Yes, once you have a mass driver, whatever its form, on the Moon, the rest more or less follows.  However, you don't really need a space station at L-1, but its certainly a nice to have, eventually. 

Plenty about space stations here, however: https://forum.nasaspaceflight.com/index.php?topic=34036

[laszlo]

Elon Musk has specifically said Spinlaunch on the moon is a great idea. Lots of synergy once starship + booster can land on earth. 

So my simple idea is that to get to Mars you need a space station. In my view building a space is a lot easier if you already have a space station. 1) So build a starship based station at L1 between the earth and the moon. 2) install a spinlaunch system on moon 2) launch regolith, water and solid co2 to L1. 3) Build structure with iron/titanium from moon materials 4) build structures to hold mass to shield a spacestation at L1   5) Launch space station from LEO  AND launch radiation shielding from L1 at same time 6) join the two on route.  I would really want 3 meters of water or regolith between the starship and space to reduce cosmic ( and solar) radiation damage. Oh space station will have to spin also :-)
 

Btw first human Mars trip will contain at least these starship based elements: 2 habitat modules complete, 2+ fuel reserves 1 lander  and 1 supply ship.

Simplistic, not simple. Way too much hand-waving about all the development work needed to make all the disparate components work together correctly.

And there's the whole question of why do we need a space station to get to Mars? Until that's answered, this is pointless.

[TrevorMonty]

]
Interesting.  did Musk say/write Spinlaunch or liner accelerator?  There is an x post on a linear accelerator.  Yes, once you have a mass driver, whatever its form, on the Moon, the rest more or less follows.  However, you don't really need a space station at L-1, but its certainly a nice to have, eventually. 

Plenty about space stations here, however: https://forum.nasaspaceflight.com/index.php?topic=34036

With spinlaunch will need somewhere to aggregate and process materials it launches, L1 is ideal location. Want Spinlaunch to apply enough DV to reach edge of moons gravity well.

I envision simple metal canisters being used to launch materials (water, metals etc) with basic gas RCS. RCS is to stablise canisters to allow tug to capture it for delivery to station. RCS and avionics can be return to surface for reuse, metal from canister used in space.

With spinlaunch supplying L1 with water none of moons precious water is wasted lifting fuel and materials to orbit. 

[lamontagne]

]
Interesting.  did Musk say/write Spinlaunch or liner accelerator?  There is an x post on a linear accelerator.  Yes, once you have a mass driver, whatever its form, on the Moon, the rest more or less follows.  However, you don't really need a space station at L-1, but its certainly a nice to have, eventually. 

Plenty about space stations here, however: https://forum.nasaspaceflight.com/index.php?topic=34036

With spinlaunch will need somewhere to aggregate and process materials it launches, L1 is ideal location. Want Spinlaunch to apply enough DV to reach edge of moons gravity well.

I envision simple metal canisters being used to launch materials (water, metals etc) with basic gas RCS. RCS is to stablise canisters to allow tug to capture it for delivery to station. RCS and avionics can be return to surface for reuse, metal from canister used in space.

With spinlaunch supplying L1 with water none of moons precious water is wasted lifting fuel and materials to orbit.

At a high launch rate, there is a question of getting all the packages together.  I need to figure out how to ensure the power demand is continuous, and combine the spin up with the spin downs.  I'm not certain they all end up in the same place if I aim for a lower orbit.  Perhaps if they all aim for L1, as you suggest, that would solve that question.
Wonder how much transit time to L1? And how do you stop at L1?  Do the vectors all add up nicely?
I agree that Moon water should stay on the Moon.  Also less polluting that lunar aluminium propulsion.  The only worry might be lunar astronomers? If we make a large number of passes above the 'quiet' side of the Moon, will they be annoyed?

[InterestedEngineer]

What is the utility for launching 200kg into Lunar Orbit, with payloads that have to handle > 1000gs?

Howitzer rounds sure (without modification), but I'm not sure what the utility of that is, unless it's Rods from God

[lamontagne]

I guess that if we have sufficient spinners, we might go a fair way into the night, launching packages, as we stop the spinners one after the other?

[Asteroza]

What is the utility for launching 200kg into Lunar Orbit, with payloads that have to handle > 1000gs?

Howitzer rounds sure (without modification), but I'm not sure what the utility of that is, unless it's Rods from God

Any kind of bulk material useful in space. Sintered regolith blocks may be useful for shielding and large structures. Water is useful for life support and manufacturing, other gases are useful for manufacturing and propellant.

But from my eyes, the greatest asset is not regolith blocks themselves, but the embodied deltaV. Downmass for momentum exchange tethers which can be dropped in the ocean can be materially advantageous for a momentum exchange tether set servicing the moon and beyond.

[lamontagne]

What is the utility for launching 200kg into Lunar Orbit, with payloads that have to handle > 1000gs?

Howitzer rounds sure (without modification), but I'm not sure what the utility of that is, unless it's Rods from God

Tens of thousands of gees  .
The utility is mainly steel/aluminium and regolith for deep space settlement construction.  If we never start on that, then we don't really need this type of launcher.
Chemical is fine for most needs otherwise, as you have demonstated at lengeth elsewhere in the site 

This is also more useful at scale, with a few hundreds/thousands operating at the same time, rather like windtubines.  A single unit might launch a few hundred tonnes per year, hardly worth the development costs, but a few hundred might launch many thousand tonnes per year, and allow for the construction of large space settlements.

[lamontagne]

Elon Musk has specifically said Spinlaunch on the moon is a great idea. Lots of synergy once starship + booster can land on earth. 

So my simple idea is that to get to Mars you need a space station. In my view building a space is a lot easier if you already have a space station. 1) So build a starship based station at L1 between the earth and the moon. 2) install a spinlaunch system on moon 2) launch regolith, water and solid co2 to L1. 3) Build structure with iron/titanium from moon materials 4) build structures to hold mass to shield a spacestation at L1   5) Launch space station from LEO  AND launch radiation shielding from L1 at same time 6) join the two on route.  I would really want 3 meters of water or regolith between the starship and space to reduce cosmic ( and solar) radiation damage. Oh space station will have to spin also :-)
 

Btw first human Mars trip will contain at least these starship based elements: 2 habitat modules complete, 2+ fuel reserves 1 lander  and 1 supply ship.

Simplistic, not simple. Way too much hand-waving about all the development work needed to make all the disparate components work together correctly.

And there's the whole question of why do we need a space station to get to Mars? Until that's answered, this is pointless.

We don't need a space station to get to Mars, but we might want a space settlement, as an alternative path to what we want to go to Mars for.  Mars development may well meet difficuties, and space settlement seems like a quasi equivalent pursuit, in particular if cheap materials are available.  Mars is a nice great pile of cheap materials.  This spin launch idea might provide a similar service in deep space.

[Exastro]

What is the utility for launching 200kg into Lunar Orbit, with payloads that have to handle > 1000gs?

Howitzer rounds sure (without modification), but I'm not sure what the utility of that is, unless it's Rods from God

Tens of thousands of gees  .

Worth noting that the acceleration depends on the inverse of the length of the arm.  For a 10-meter arm and a speed of 1.8 km/sec (low Lunar orbit) the acceleration is 33000 gee.  But with a 100-meter arm it's 3300 gee, and a 1-km arm makes it a much more manageable 330 gee.

In Earth's atmosphere such long arms are pretty hard to make, since they require enormous vacuum chambers.  On Luna they should be comparatively straightforward.  One could imagine a tether that reels out as the arm spins up, reaching lengths of perhaps 10s of kilometers before the payload is released, and never exerting more than a few gee on the payload.  You might even be able to launch passengers that way!

[lamontagne]

What is the utility for launching 200kg into Lunar Orbit, with payloads that have to handle > 1000gs?

Howitzer rounds sure (without modification), but I'm not sure what the utility of that is, unless it's Rods from God

Tens of thousands of gees  .

Worth noting that the acceleration depends on the inverse of the length of the arm.  For a 10-meter arm and a speed of 1.8 km/sec (low Lunar orbit) the acceleration is 33000 gee.  But with a 100-meter arm it's 3300 gee, and a 1-km arm makes it a much more manageable 330 gee.

In Earth's atmosphere such long arms are pretty hard to make, since they require enormous vacuum chambers.  On Luna they should be comparatively straightforward.  One could imagine a tether that reels out as the arm spins up, reaching lengths of perhaps 10s of kilometers before the payload is released, and never exerting more than a few gee on the payload.  You might even be able to launch passengers that way!

Yes, there is an old thread on that, there are a number of problems with the idea, however.
https://forum.nasaspaceflight.com/index.php?topic=5420

This is more about the idea that a relatively short, rigid arm might be more practical, and that it is beeing developped by Spinlaunch for real, so the development costs for a Moon version might be quite low.
For people, regular chemical propulsion is probably the best solution.
There is a military standard for equipment used for artillery shells that covers 16 000 g.  But I expect that keeping the active part as simple as possible would be a good idea.
Anything launched from the Moon that is not faster than escape velocity needs a added thruster (or an orbital catcher), or it will return to the surface with unfortunate results.

[redneck]

Spin launch on the moon will have competition from other concepts that work in vacuum but not from Earth in atmosphere.

A gun launch for one that is easy to calculate. 10 foot caliber pushed by 100 psi at 10 gee would be about 50 tons per shot. 17 seconds to reach minimal Lunar orbital velocity needs about 10 miles of "barrel". Recovery of some of the volatiles possible at end of acceleration. Need on board propulsion for maneuvering, could possibly be human rated.

Rotovator in Lunar orbit could use incoming mass from Earth to lift outgoing mass from the moon. Various mass drivers. Possibility of very cost effective Lunar ISRU propellant.  Might remember more later, early coffee thoughts.

[catdlr]

Spin launch on the moon will have competition from other concepts that work in vacuum but not from Earth in atmosphere.

A gun launch for one that is easy to calculate. 10 foot caliber pushed by 100 psi at 10 gee would be about 50 tons per shot. 17 seconds to reach minimal Lunar orbital velocity needs about 10 miles of "barrel". Recovery of some of the volatiles possible at end of acceleration. Need on board propulsion for maneuvering, could possibly be human rated.

Rotovator in Lunar orbit could use incoming mass from Earth to lift outgoing mass from the moon. Various mass drivers. Possibility of very cost effective Lunar ISRU propellant.  Might remember more later, early coffee thoughts.

It seems a "rail Gun" would work better and be easier to build than Spinning, but I digress.

[redneck]

And the rail gun could be set up in such a way as to “catch”incoming vehicles generating the power to send other stuff on. 

[TrevorMonty]

It seems a "rail Gun" would work better and be easier to build than Spinning, but I digress.

Rail guns are huge under taking, they need kms of track along with electro magnets. Track has to be dead straight over very mixed terrain. There is no half measures go big or go home. Spinlaunch can start with single low payload mass launcher, with bigger launchers added over time.

[lamontagne]

Spin launch on the moon will have competition from other concepts that work in vacuum but not from Earth in atmosphere.

A gun launch for one that is easy to calculate. 10 foot caliber pushed by 100 psi at 10 gee would be about 50 tons per shot. 17 seconds to reach minimal Lunar orbital velocity needs about 10 miles of "barrel". Recovery of some of the volatiles possible at end of acceleration. Need on board propulsion for maneuvering, could possibly be human rated.

Rotovator in Lunar orbit could use incoming mass from Earth to lift outgoing mass from the moon. Various mass drivers. Possibility of very cost effective Lunar ISRU propellant.  Might remember more later, early coffee thoughts.

Propellant needs to be manufactured. This will take much more energy for the same amount of launched mass.  Plus no nitrogen and little carbon on the Moon, so it’s hard to do in situ production.  And a gun also accelerates the gas, another loss.