Patent RU2266420C2 — Aerospace Laser Jet Engine (Omnidirectional LSD Propulsion)
Bibliographic Information
| Field | Details |
|---|---|
| Patent Number | RU2266420C2 |
| Title | Aerospace Laser Jet Engine |
| Inventors | A.A. Ageichik (А.А. Агейчик), M.S. Egorov (М.С. Егоров), Y.A. Rezunkov (Ю.А. Резунков), A.L. Safronov (А.Л. Сафронов), V.V. Stepanov (В.В. Степанов) |
| Assignee | Federal State Unitary Enterprise Research Institute for Complex Testing of Optoelectronic Devices and Systems (ФГУП НИИКИ ОЭП), Russia |
| Filing Date | October 8, 2003 |
| Application Number | RU2003129824/11A |
| Publication Date | December 20, 2005 |
| PCT Filing | WO2005033498A1 (April 14, 2005); PCT/RU2003/000581 |
| Jurisdiction | Russia (RU) |
Abstract
The invention relates to jet propulsion systems for aerospace vehicles, enabling orbital flight capability. The engine contains a pulsed periodic laser radiation source, an optical unit with radiation concentrator featuring cone-shaped reflectors with parabolic generatrices, a system forming plane radiation fronts, and a gas-dynamic unit coaxial to the concentrator. The first reflector concentrates laser beams via short-focus parabolic surfaces. The gas-dynamic unit comprises a pressure pulse receiver positioned at the rear of the first reflector base and a jet nozzle positioned at distance, forming an input slot for laser radiation. A secondary reflector with arc-shaped surface directs focused radiation to the nozzle slot region. Key advantage: "possibility of mounting engine on board the craft, building of thrust irrespective of relative orientation of craft and laser energy source."
Claims
Claim 1 (Single Independent Claim): An aerospace laser jet engine containing a source of pulsed laser radiation, an optical unit with radiation concentrator where the first reflector exhibits mirror cone-shaped rotation form with surface generatrix comprising short-focus parabola sections, forming an optical system for receiving and matching laser beam aperture with optical unit dimensions and plane radiation front formation, and a gas-dynamic unit located coaxially with concentrator, characterized by: utilizing pulsed-periodic laser radiation source; gas-dynamic unit designed as pressure pulse receiver positioned at rear of first reflector and coinciding with its base; jet nozzle installed at distance from base forming slot for laser radiation input; radiation concentrator equipped with additional mirror reflector coaxial to first reflector, formed as rotation figure with arc-shaped surface generatrix; additional reflector positioned in path of beam focused by first reflector such that concentrator focal region locates in slot region.
Description / Specification
Background and Technical Problem
"The idea of using laser jet propulsion to organize the flight of vehicles began to be developed in the early 70s." Traditional laser-driven engines (including US6488233B1, cited as prior art prototype) direct radiation from the nozzle side, creating disadvantages:
- Inability to control thrust vector direction independently of apparatus orientation
- Degradation of laser beam quality through interaction with exhaust gases
- Optical surface deterioration from extreme thermal and chemical conditions of the nozzle exhaust
Technical Solution: Separation of Optical Concentrator from Reactive Nozzle
The proposed design separates the laser beam concentrator from the reactive nozzle both functionally and structurally, directing laser input from the opposite side of exhaust flow. "Optical surfaces of the concentrator elements do not experience significant shock and thermal loads, as well as physico-chemical effects during the operation."
The critical innovation over US6488233B1: the conical primary reflector with parabolic generatrix enables reception of laser power from ANY direction relative to the vehicle axis, not just along the flight axis. The dual-reflector system (cone-shaped primary + arc-generatrix secondary) is a variant of the Cassegrain telescope design optimized for maximum beam-capture solid angle and minimum aberration.
Key Components
Optical Concentrator System:
- First reflector: cone-shaped mirror with short-focus parabolic generatrix enabling ring-focused laser concentration
- Second reflector: arc-shaped surface for redirecting focused radiation to engine inlet
- Forming optics: adapts laser beam aperture to optical unit dimensions, establishes plane wavefront
Gas-Dynamic Unit:
- Pressure pulse receiver: positioned at rear of first reflector base; provides optimal breakdown region placement
- Jet nozzle: separated from receiver by gap serving as aerodynamic window; optimal nozzle length equals double the cross-sectional diameter
- Input slot: annular gap enabling laser radiation entry while minimizing thrust losses
Operational Principle
Pulsed laser radiation passes through forming optics achieving plane wavefront, then strikes first (cone-shaped) reflector producing ring-focus at circle Φ₁. Second (arc-generatrix) reflector redirects this focused radiation through input slot into working medium region where optical breakdown occurs, creating expanding hot plasma. Resulting shock waves and gas flows generate thrust through output nozzle.
Minimum slot width formula:
l = λ × ((R-r)/d)
where:
- λ = laser wavelength
- d = meridional laser beam dimension on second reflector surface
- r = annular slot inner radius
- R = second reflector mean radius
Design Parameters (Prototype Specifications)
| Component | Specification |
|---|---|
| First reflector base diameter | 100 mm |
| First reflector height | 110 mm |
| Pressure receiver diameter | 60 mm |
| Pressure receiver height | 12 mm |
| Second reflector inclination to axis | 24° |
| Second reflector reflecting length | 27 mm |
| Second reflector mean diameter | 184 mm |
| Nozzle diameter | 60 mm |
| Nozzle length | 90–120 mm |
| Prototype total mass | 2.6 kg |
| Surface deviation tolerance | ≤20 μm |
| Assembly tolerance | ≤50 μm |
Experimental Results
Testing employed pulsed CO₂ laser (unstable telescopic cavity, M = 2.3):
- Pulse energy: 100–150 J
- Pulse duration: 15 μs
- Wavelength: 10.6 μm
Measured reactive recoil coefficient C_m: 10–15 dyne/W (matching theoretical estimates of ~12 dyne/W with slot). Without slot: calculations indicated ~30 dyne/W, demonstrating slot-related efficiency reduction exceeding 2×. Plasma formation photographs showed 3 cm diameter disk under normal environmental conditions.
Performance Calculations (at 200 kW laser power)
| Parameter | Value |
|---|---|
| Specific impulse I_sp | ~10³ seconds |
| Thrust T | 40 N |
| Mass fuel consumption | 4.2 g/s |
| Laser pulse energy | ~40 J per pulse |
| Pulse repetition rate | ~5 kHz |
| Nozzle length L | 1.85 m |
| Nozzle outlet diameter | 0.996 m |
| Critical section diameter d* | 4.65 mm |
| Gas density at critical section ρ* | 0.789 kg/m³ |
| Specific heat ratio γ | 1.4 |
| Nozzle cone angle θ | 30° |
Comparison with US6488233B1 (Myrabo Lightcraft)
| Feature | US6488233B1 (Myrabo, US Air Force) | RU2266420C2 (Russia, НИИКИ ОЭП) |
|---|---|---|
| Beam reception | Axial only (along flight axis) | Omnidirectional (360°) |
| Primary reflector | Parabolic afterbody | Conical with parabolic generatrix |
| Secondary reflector | None | Arc-generatrix coaxial secondary |
| Attitude requirement | Must face beam source | None — works from any angle |
| Filed | 2001 | 2003 |
| Assignee | US Air Force | Russian defense optoelectronics institute |
Technical Classifications
- B64G1/409 — Cosmonautic vehicles: unconventional spacecraft propulsion systems
- B64G1/413 — Ion or plasma engines
- F02K9/60 — Rocket-engine decomposition chambers
- F03H1/00 — Producing reactive propulsive thrust using plasma
Prior Art / Citations
| Reference | Details |
|---|---|
| US3392527 (1968) | Cornell Aeronautical — Laser-stimulated ionic emission propulsion method |
| US4036012 (1977) | US Army — "Laser powered rocket engine using a gasdynamic window" |
| RU2044226C1 (1995) | Tveryanovich — Solar energy plant |
| US6488233B1 (2002) | US Air Force / Myrabo — "Laser propelled vehicle" — Selected as prototype reference |
Patent Family
- WO2005033498A1 — International publication (April 14, 2005)
- RU2003129824A — Russian publication (April 10, 2005)
- PCT/RU2003/000581 — International application
Subsequent Citations
This patent has influenced 13+ subsequent laser propulsion patents including spacecraft engines, laser-plasma engines, and laser rocket engine variations filed through 2021.
Citations
- Google Patents: RU2266420C2
- PCT/RU2003/000581 (WO international filing)
- US6488233B1 (Myrabo Lightcraft, cited as prototype)
Patent text compiled from Google Patents. Machine-translated from Russian; original Russian text at the above URL.