Space Trebuchet (also referred to by the author as the "Nizhny Novgorod lunar trebuchet" and the "Nizhny Novgorod lunar catapult") — a projectile device with which Nizhny Novgorod engineer-physicist Igor Knyaginichev, publishing under the pen name Professor Rastolkovskiy, proposes to develop near-lunar orbit: a massive rotating sling in the form of a rod sharpened at both ends, which accelerates spacecraft without consuming fuel.[1] The concept forms part of a body of ideas the author has been developing since 2005 under the general name Trebuchet-Cosmonautics.[1]
Design
At the heart of the device is a rotating sling-catapult: a long rod, sharpened at both ends, rotating around its center of mass in orbit. Spacecraft attach to its ends and are released already at the required velocity.[1]
For the tether material, the author proposes not an ordinary cable but his own construction, which he calls an "electrostatic tether"; according to his diagrams, this tether makes up the orbit-exchange sling-catapult, with the payload attached to it by stays. The very name "space trebuchet" alludes to the most powerful projectile weapon of antiquity, in which a falling counterweight accelerated a projectile on a long lever arm.[1]
Mass Exchange Instead of Fuel
The key idea of the concept is that the sling carries no energy source on board. When two bodies of equal mass meet at intersecting orbits, they can exchange velocity vectors — the author compares this to a billiard ball collision.[3] This means that the load to be raised and the load to be lowered pay for each other: the payload heads to the Moon, while lunar soil of equal mass is dispatched in the opposite direction.[3]
In the author's worked example, the sling rotates at 840 meters per second and transfers payloads at orbital intersection points.[3] On the lunar surface, the final link in the chain is a "carousel" — a rotating device that catches and decelerates the arriving spacecraft.[3]
The carousel is brought to a stop, and the cosmonaut steps out onto the surface of the Moon.
The Author's Calculations
Knyaginichev attributes the high cost of spaceflight to the fact that almost all of the mass launched by a rocket consists of its own propellant and structure. By his estimate, a mass-exchange scheme would require spending 1–2 percent of mass on transit rather than roughly 90 percent as with a rocket — a roughly nine-hundred-fold reduction in propellant consumption.[3]
From this, the author derives his other figures: delivery of tens of tonnes of cargo to the Moon per month, a delivery cost roughly ten times lower than by rocket, and four times lower for geostationary orbit.[3] All these figures remain the author's own calculated estimates; the concept has not undergone engineering verification.
Place Among the Author's Concepts
The space trebuchet is not a standalone invention but part of a coherent system of ideas. The author calls his overall approach — in which a rocket serves only to exit the atmosphere while acceleration to orbital velocities is delegated to a rotating rod — Trebuchet-Cosmonautics.[1]
The atmospheric-exit stage in this system is occupied by the Razgonoplan (Boost-Plane) — a glider with a water-jet engine — while the same principle of rotating carousels, transferred to the ground, the author proposes as an urban transit system under the name Aerometro.[2]
The Author
Igor Knyaginichev was born on 16 July 1960 in Yakutsk.[2][4] From 1977 to 1982 he studied at the radiophysics faculty of Gorky's Lobachevsky University, and worked at the Nizhny Novgorod Lenin Television Plant.[2]
He adopted the pen name "Professor Rastolkovskiy" for popular presentations of his ideas. Since 13 January 2018 he has been publishing on Habr, where he describes himself as a radiophysicist by training and a theorist of the use of slings in space, and as the inventor of an orbit-exchange space system; he lives in Moscow and the Moscow Region.[4]
Fate of the Idea
The concept has not been given engineering form and remains the author's own conception, set out on his personal website and in his online publications.[1][3] Knyaginichev published a detailed exposition of the mass-exchange scheme on 17 February 2019 on Habr — his only article on that platform.[3][4]
Sources
- razgonoplan.nnewer.ru — Trebuchet Cosmonautics: the author's exposition of the concept dating from 2005 (archive)
- razgonoplan.nnewer.ru — Professor Rastolkovskiy — pen name of engineer-physicist Igor Knyaginichev (archive)
- habr.com — Habr — Did you know that using the law of conservation of energy it is possible to deliver cargo to the Moon far more easily, through mass exchange? (17 February 2019) (archive)
- habr.com — Habr — Author profile: radiophysicist, theorist of the use of slings in space (archive)