Nuclear thermal rockets using indigenous extraterrestrial propellants

A preliminary examination of a concept for a Mars and outer solar system exploratory vehicle is presented. Propulsion is provided by utilizing a nuclear thermal reactor to heat a propellant volatile indigenous to the destination world to form a high thrust rocket exhaust. Candidate propellants, whose performance, materials compatibility, and ease of acquisition are examined and include carbon dioxide, water, methane, nitrogen, carbon monoxide, and argon. Ballistics and winged supersonic configurations are discussed. It is shown that the use of this method of propulsion potentially offers high payoff to a manned Mars mission. This is accomplished by sharply reducing the initial mission mass required in low earth orbit, and by providing Mars explorers with greatly enhanced mobility in traveling about the planet through the use of a vehicle that can refuel itself each time it lands. Thus, the nuclear landing craft is utilized in combination with a hydrogen-fueled nuclear-thermal interplanetary launch. By utilizing such a system in the outer solar system, a low level aerial reconnaissance of Titan combined with a multiple sample return from nearly every satellite of Saturn can be accomplished in a single launch of a Titan 4 or the Space Transportation System (STS). Similarly a multiple sample return from Callisto, Ganymede, and Europa can also be accomplished in one launch of a Titan 4 or the STS

Use of magnetic sails for advanced exploration missions

The magnetic sail, or magsail, is a field effect device which interacts with the ambient solar wind or interstellar medium over a considerable volume of space to generate drag and lift forces. Two theories describing the method of thrust generation are analyzed and data results are presented. The techniques for maintaining superconductor temperatures in interplanetary space are analyzed and low risk options presented. Comparisons are presented showing mission performance differences between currently proposed spacecraft using chemical and electric propulsion systems, and a Magsail propelled spacecraft capable of generating an average thrust of 250 Newtons at a radius of one A.U. The magsail also provides unique capabilities for interstellar missions, in that at relativistic speeds the magnetic field would ionize and deflect the interstellar medium producing a large drag force. This would make it an ideal brake for decelerating a spacecraft from relativistic speeds and then maneuvering within the target star system

Methods of Higher Alcohol Synthesis

Systems, catalysts, and methods are provided for transforming carbon based material into synthetic mixed alcohol fuel

Survey of highly non-Keplerian orbits with low-thrust propulsion

Celestial mechanics has traditionally been concerned with orbital motion under the action of a conservative gravitational potential. In particular, the inverse square gravitational force due to the potential of a uniform, spherical mass leads to a family of conic section orbits, as determined by Isaac Newton, who showed that Kepler‟s laws were derivable from his theory of gravitation. While orbital motion under the action of a conservative gravitational potential leads to an array of problems with often complex and interesting solutions, the addition of non-conservative forces offers new avenues of investigation. In particular, non-conservative forces lead to a rich diversity of problems associated with the existence, stability and control of families of highly non-Keplerian orbits generated by a gravitational potential and a non-conservative force. Highly non-Keplerian orbits can potentially have a broad range of practical applications across a number of different disciplines. This review aims to summarize the combined wealth of literature concerned with the dynamics, stability and control of highly non-Keplerian orbits for various low thrust propulsion devices, and to demonstrate some of these potential applications

The conceptual design of a Mars nuclear landing and ascent vehicle utilizing indigenous propellant

Thesis (Ph. D.)--University of Washington, 1992Interplanetary travel and exploration can be greatly facilitated if indigenous propellants can be used in place of those transported from Earth. Nuclear thermal rockets offer significant promise in this regard, as in principle, any gas at all can be made to perform as a propellant to some extent.In particular, the Martian atmosphere is composed of 95% CO\sb2. Under Martian conditions, this gas can be liquified by simple compression to about 100 psi, and remains storable without refrigeration. When heated to 2400 K and exhausted out of a rocket nozzle, a specific impulse of about 226 s can be achieved. This is sufficient for flights from the surface to orbit or from one point on the Martian surface to any other point on the planet. Because the power requirements for acquiring CO\sb2 are quite low, the propellant acquisition system can travel with the vehicle, allowing it to refuel itself each time it lands. Thus this vehicle concept, which is termed a NAV (Nuclear Ascent Vehicle), offers unequalled potential to achieve planetwide mobility, allowing complete global access for the exploration of Mars, and potentially can reduce the initial mission mass in LEO as well.This dissertation presents the results of an extensive study which centered on the conceptual design of a NAV vehicle with surface to orbit capability. Carbon dioxide was the propellant of choice, with some examination of alternate concepts using other propellants. The NAV configuration defined by the conceptual design was used as a basis for defining engine performance requirements, and a detailed study of a potential NAV engine that could meet these requirements was then conducted. The resulting NAV/engine combination was then examined in a series of trade studies to determine its potential merit in assisting in the exploration of Mars