Melvin J. Bulman

Combined Cycle Propulsion: Aerojet Innovations for Practical Hypersonic Vehicles

Sustained hypersonic (M>5) atmospheric flight is best performed with a supersonic combustion ramjet (Scramjet). Scramjet-powered flight with durations over 100 seconds (X51) has now been demonstrated. A Scramjet-powered vehicle requires a “boost” to its ramjet takeover (RTO) speed where it can provide adequate acceleration to its cruise speed. All Scramjet powered flights to date have used a solid rocket booster motor that was dropped just before RTO. Although this is practical for demonstration flights, it is unaffordable for an operational vehicle, particularly when the vehicle is to be reused. Reusable hypersonic vehicles require a synergistically integrated self boosting capability. In this paper, we describe the issues such propulsion systems must address and discuss various Aerojet solutions to make them practical.

Human Exploration and Settlement of the Moon Using LUNOX-Augmented NTR Propulsion

An innovative trimodal nuclear thermal rocket (NTR) concept is described which combines conventional liquid hydrogen (LH2)‐cooled NTR, Brayton cycle power generation and supersonic combustion ramjet (scramjet) technologies. Known as the liquid oxygen (LOS)‐augmented NTR (LANTR), this concept utilizes the large divergent section of the NTR nozzle as an ‘‘afterburner’’ into which LOX is injected and supersonically combusted with nuclear preheated hydrogen emerging from the LANTR’s choked sonic throat—‘‘scramjet propulsion in reverse.’’ By varying the oxygen‐to‐hydrogen mixture ratio (MR), the LANTR can operate over a wide range of thrust and specific impulse (Isp) values while the reactor core power level remains relatively constant. As the MR varies from zero to seven, the thrust‐to‐weight ratio for a 15 thousand pound force (klbf) NTR increases by ∼440%—from 3 to 13—while the Isp decreases by only ∼45%—from 940 to 515 seconds. This thrust augmentation feature of the LANTR means that ‘‘big engine’’ perform...

Multimodal space nuclear thermal propulsion and power system for space industrialization

American industry will capitalize on available aerospace and nuclear technologies to continue space industrialization if shown a highly profitable approach. One is suggested that depends upon a sequence of co‐enabling mission architecture, propulsion, and payload improvements, which are based on concepts developed recently by our aerospace, nuclear, and chemical propulsion communities. Sequential development of specific cislunar and lunar industries are suggested to minimize early investments. Lunar and subsequent inner solar system industrial growth becomes feasible with lunar oxygen use in the recommended, multimodal, space nuclear propulsion and power system that provides the high specific impulse, system flexibility, life, and reliability needed to propel and power early spacecraft and outposts as well as future vehicles in more demanding mission architectures.

US/CIS integrated NTRE

The paper describes the Nuclear Thermal Energy (NTRE) engine, developed by taking advantage of mature fuel technology developed in the former Soviet Union, thus shortening the development schedule of this engine for moon and Mars explorations. The near-term NTRE engine has a number of features that provide safety, mission performance, cost, and risk benefits. These include: (1) high-temperature long-life CIS fuel, (2) high-pressure recuperated expander cycle, (3) assured restart, (4) long-life cooled nozzle with thin inner wall, (5) long-life turbopumps, (6) heat radiation and electrical power generation, and (7) component integration synergy. Diagrams of the reactor core, the recuperated bottoming cycle flow schematic, and the recuperated bottoming cycle engine schematic are presented.

US/CIS integrated NTRE concept

The team of Aerojet, Energopool and Babcock & Wilcox has prepared a near‐term Nuclear Thermal Rocket Engine (NTRE) concept that takes advantage of mature fuel technology developed in the former Soviet Union. This proven, advanced fuel appreciably shortens the development schedule of this engine for Moon and Mars exploration. Our near term engine has a number of features that provide safety, mission performance, cost and risk benefits, including: (1) High temperature, long life CIS fuel, (2) high pressure, recuperated topping cycle, (3) assured restart, (4) long life, cooled nozzle with thin inner wall, (5) long life turbopumps, (6) heat radiation and electrical power generation, and (7) component integration energy.