From RocketSlinger@SBCGlobal.net (email me there please)… This is a sub-site to main site at www.rocketslinger.com …

This web page last updated 29 May 2022

High-“G”-Force Impact-Landings Methods of Cargo Delivery to the Moon, Spinning-Barrel-Style

Abstract / Pre-Summary

This sub-page to www.rocketslinger.com is meant to supplement the previously-published document, “High-“G”-Force Impact-Landings Methods of Cargo Delivery to Earth’s Moon (or Other Heavenly Bodies Lacking an Atmosphere)”. What is described here is a lower-maintenance-costs version of the “linear decelerator” as described there. One version described there involved the use of “break sticks”, which would need to be replaced for every use cycle. “Break sticks” were envisioned as being needed to counter excessive spin-speeds that might otherwise accumulate in the impacting cargo body, from unbalanced friction (with the surface of the moon) on only one side of the cargo body.

Described here is a method derived from the British spinning-barrel-bomb (AKA “bouncing bomb”) design, which was used to destroy NAZI dams, during WW II. As our back-spinning-barrel cargo-vessel impact-lands in a trough of moon dust (plus moon sand and gravel perhaps), the back-spin of the vessel kicks dust (etc.) in front of it, some of which will re-impact the spinning vessel, slowing it down. Spin energy is killed, and traded off for deceleration energy, that is. Thus, the need for the previously-described “break sticks” is eliminated.

Other details are described here, such as, where, optimally, do we impart the needed spin energy (best answer: in or on a dedicated-purpose moon-orbiting cargo-transfer station), and how to we kill the imparted, accumulated spin energy on an orbiting cargo-transfer station. An answer is, use a large spinning gyroscopic mechanism, then periodically “dump” the accumulated spin to ejected masses, such as ion propulsion, ejected slag rock imported from the moon, or ejected space probes, ejected by a “Spin Launch”-type device. See https://www.spinlaunch.com/ .

As with other sub-pages of www.rocketslinger.com , the intent here is to “defensively publish” propulsion-related (and “misc.”) ideas, to make them available to everyone “for free”, and to prevent “patent trolling” of (mostly) simple, basic ideas.

Introduction

See the above abstract for the basics, some of which will not be repeated here. See also “High-“G”-Force Impact-Landings Methods of Cargo Delivery to Earth’s Moon (or Other Heavenly Bodies Lacking an Atmosphere)”. This being a rather long-winded title, it will henceforward be called the “parent document”. See this “parent document” Figures 4-5-6, which show a trough (or “linear decelerator”) full of moon-dust (etc.), with Figure #6 showing the “break sticks” that are eliminated here.

For details about the British “bounce bomb” that we’re cribbing off of, here, see https://en.wikipedia.org/wiki/Bouncing_bomb and https://www.sciencefocus.com/science/how-did-the-bouncing-bomb-work/ and (best or most detailed) https://www.ukessays.com/essays/physics/physics-dambusters-bouncing-bomb-9609.php .

Enough already with the basics! Let’s get ON with it!

The Spinning-Barrel Cargo Vessel

The (sacrificial) cargo vessel should be a robustly built, thick-walled metallic vessel. Note that the metal shell can be molten down or otherwise re-used on the moon. Carbon-fiber wrapping it is another option, though. It should be spun up to a speed approaching the maximum (beyond which it would tear itself apart, from centrifugal force), so as to maximize spin energy that can be traded off for deceleration. Optionally, the vessel MIGHT be constructed to include strategically located RFID (Radio Frequency Identity Devices) to assist in finding fragments of the vessel, if they get buried in the moon dust of the high-G “landing strip”. Also optionally, the periphery (outer diameter) might optimally be equipped with “saw teeth” to grip the moon dust better, and throw it forwards, into the path of the cargo vessel.

Figure #1

Repeated use of the “high-G-impact” landing strip will tend to force the moon dust (plus sand and maybe gravel) “downstream”. We COULD constantly add more dust (etc.) at one (upstream) end, and continuously lengthen the “runway” at the downstream end. With a longer runway, we could tweak some variables, and reduce “G” forces, thus accommodating cargo which is less tolerant of high “G” forces, as the runway grows longer and longer over time. Detailed math for all of this is shown in the parent document (“G” forces v/s runway length and deceleration time elapsed). And-or, we could periodically collect moon dust with moon-moving machinery, pick it up at the “downstream” end, and dump it off at the upstream end, so that it (dust, sand, etc.) can start the journey all over again.

Or, given that the usage rate is high enough (and that we have the money! Always, we need enough money!), we MIGHT want to put up TWO moon-orbiting cargo-handling “motherships”, in pro-grade v/s retrograde orbits, so as to alternately smash the moon dust back and forth, in alternate directions! This gives us higher capital costs, yes, but also lower maintenance costs! So it is past high time for a topic-change new heading here…

Moon-Orbiting Cargo Motherships

The cargo vessels (from Earth for a long time to come; from other sources eventually) COULD come directly, with “spin energy” added “en route” (along the way), but that would require wasted (spin-adding) reaction mass. Launching them with sufficient “spin energy” already added is a ridiculous idea, and I’m scarcely inclined to bother to explain why. But I’m getting ahead of myself anyway…

A cargo-handling permanently-stationed mothership (in moon orbit) is a good idea, in this scheme! TWO of them, one orbiting pro-grade, one orbiting retro-grade, would be even better, for reasons already explained above. To keep them from smacking into one another (while also keeping them both near-perfectly aligned with our “landing strip”), we’ll want to have them assume orbits at different elevations above the moon’s surface. Time for another drawing…

Figure #2

The two “cargo motherships” take in non-spinning cargo vessels from Earth (or from other locations further in the future), add spin energy, and then (at least in a roughly balanced manner) alternate “taking shots on goal”, with the goals being the opposing ends of the landing strip on the moon. By the way… substitute ice for moon dust, in the further-distant future, if we’re shooting for the moons of the gas giants… This should be obvious.

Well then, there’s not a whole bunch more to go over! These cargo-handling cargo-transfer motherships? Where do they get their energy from, to add spin energy to the cargo vessels? Nuclear energy and solar energy sound like good candidates to me! (Plus electrical motors, obviously!)

As they add spin energy in one direction, to the cargo vessel, they will “want to” spin in the opposite direction, of course! We have equal and opposite actions and reactions, always! How do we handle that? TEMPORARILY, we cause a large internal-to-the-mothership gyroscope to spin in the opposite direction (smaller gyros on the two other spin axes, for a complete stability solution, also sounds good). The “gyro” will NOT have infinite capacity, of course!

To bleed off accumulated spin energy, we can:

‘A) Add high-specific-impulse thrusters, such as ion propulsion, or nuclear-thermal thrusters, or

‘B) Bring slag rock or other low-cost materials (waste materials) from the moon, or from asteroids (later on), for cheap reaction mass, and shoot them off in the right directions (at the right times, so as to not hit anyone!), or

‘C) Add giant solar sails and “tack” them the right way? I suspect this isn’t plausible, for the scales of forces involved… Or

‘D) (My favorite choice!) add a “Spin Launch”-type device (see https://www.spinlaunch.com/ ) to shoot off planetary and-or interstellar probes, when the right opportunities present themselves! This may not be often… So this method would likely need to be combined with other methods.

Other clever combinations and variations of the above will likely make sense. Choice “B” variations might include solidifying your waste materials to be shot off, so that one can SPIN the material (for spin-energy-dumping of course), as well as get reaction mass out of it. If solidifying it (to withstand high spin energy) is expensive or impractical, we could even get “Rube Goldberg-esque” here, and devise a large shotgun-style device, where the shotgun-cartridge segment of the barrel (if not the entire barrel) is rotated at high speeds, before the slag or other waste is “shot off”. Sounds like Wyle Coyote designed it, yes! But it COULD work, and be more efficient at spin-energy-dumping!

I have no special expertise or any more plausible ideas concerning any associated matters here, so I will sign off at this time. This concludes my ideas as of this time. Once again, comments or questions (or idea contributions) are welcomed at RocketSlinger@SBCGlobal.net …

Stay tuned… Talk to me! RocketSlinger@SBCGlobal.net

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References

Stauffer, Titus. (2020). High-“G”-Force Impact-Landings Methods of Cargo Delivery to Earth’s Moon (or Other Heavenly Bodies Lacking an Atmosphere)