Chemical and nuclear propulsion are fundamentally limited by their exhaust velocity ( ( \sim 500 , s) to ( \sim 10^6 , s) for ion drives). Antimatter provides the highest energy density ((9 \times 10^16 , J/kg)) but suffers from catastrophic storage issues. The Black Hole Injector (BHI) offers an alternative: a self-regulating black hole that converts infalling matter into radiation with an efficiency ( \eta ) exceeding nuclear fusion by two orders of magnitude.
The emitted Hawking radiation (predominantly gamma rays at ( T \sim 10^11 , K ) for ( M = 10^6 ) kg) is absorbed by a tungsten-lithium heat exchanger, driving a closed-cycle Brayton turbine. The relativistic jets (from superradiance) are collimated by external magnetic nozzles to produce thrust.
A naked singularity is impossible (cosmic censorship). Thus, the BH must be isolated. We propose a magnetic mirror trap (modified Penning trap) using superconducting coils generating 100 T fields, located 1 km from the BH to avoid spaghettification. The BH is levitated via the Meissner-like effect against a superconducting stator.
[ P_\texttotal = P_\textHawking + P_\textSuperradiant + P_\textAccretion ] black hole injector
If ( M_BH < M_\textcritical \approx 10^11 , \textkg ), the Hawking radiation power exceeds the Eddington limit, causing rapid evaporation. For our ( 10^6 ) kg BH, evaporation time without refueling is: [ t_\textevap = \frac5120 \pi G^2 M^3\hbar c^4 \approx 4.5 \times 10^7 , \texts , (\approx 1.4 , \textyears) ] Thus, continuous fuel injection is mandatory. A feedback loop adjusts injection rate to maintain ( \dotM \approx 0 ). Failure leads to an explosion equivalent to ( 10^6 ) kg converting to energy — a 20 Gigaton blast, necessitating failsafe detachment systems.
A linear accelerator (1 TeV) injects protons tangentially into the ergosphere. The injector uses a pulsed neutron beam to avoid Coulomb repulsion. Injection rate ( \dotm ) is tuned such that the BH’s mass remains constant: [ \dotM \textBH = \dotm \textin - \fracP_H + P_\textjetc^2 = 0 ]
Note: The thrust exceeds a Saturn V by a factor of 5 while using 10 million times less fuel mass. Chemical and nuclear propulsion are fundamentally limited by
A. J. Vance, L. M. Chen Affiliation: Institute for Advanced Propulsion Studies, Caltech / MIT (Hypothetical)
The Black Hole Injector: A Theoretical Framework for Mass-Energy Conversion and Ultra-Relativistic Propulsion
| System | (I_sp) (s) | Thrust (N) | Storage Hazard | |--------|--------------|------------|----------------| | Chemical | (300-450) | (10^7) | Low | | Nuclear Thermal | (900) | (10^6) | Medium | | Ion Drive | (3,000) | (10) | Low | | Antimatter | (10^7) | (10^5) | Extreme | | | (2.4 \times 10^7) | (10^7) | Extreme (but passive) | The emitted Hawking radiation (predominantly gamma rays at
This paper proposes a novel propulsion concept, the Black Hole Injector (BHI), which utilizes a primordial or artificially generated microscopic black hole (BH) as a catalyst for complete mass-to-energy conversion. Unlike conventional matter-antimatter engines, the BHI operates by injecting baryonic matter into a stable, electrically charged, rotating black hole (Kerr-Newman metric). Through Hawking radiation and superradiant scattering, the BH re-emits up to ~40% of the injected rest mass as directed high-energy gamma rays and relativistic plasma jets. We derive the thermodynamic limits, stability criteria (the "sphericity constraint" to avoid runaway evaporation), and a theoretical specific impulse (I_sp > 10^7 , s). The BHI circumvents the antimatter storage problem by using ordinary hydrogen as fuel. We conclude with a feasibility analysis of containment using nested magnetic and gravitational shields.
For a BH of mass ( M ), the Hawking luminosity is: [ P_\textH = \frac\hbar c^615360 \pi G^2 M^2 \approx 3.6 \times 10^32 \left( \frac10^6 \textkgM \right)^2 \textW ]
[1] Hawking, S.W. (1975). Particle creation by black holes. Commun. Math. Phys. 43, 199. [2] Penrose, R. (1969). Gravitational collapse: The role of general relativity. Nuovo Cimento 1, 252. [3] Misner, C.W., Thorne, K.S., Wheeler, J.A. (1973). Gravitation . Freeman. [4] Crane, L., Westmoreland, S. (2009). Are black hole starships possible? arXiv:0908.1803 . This research was supported by a grant from the Initiative for Interstellar Studies (i4is), hypothetical division.