KSC Next Gen Site - Highly Reusable Space Transportation

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Highly Reusable Space Transportation (HRST) Study

A rocket works by combining fuel with oxidizer, but all the oxygen, unlike cars or airplanes, is carried aboard the rocket. Not so for cars or airplanes. The physics of a rocket mandates that most of the rocket at lift off is thus propellant. Most of a rocket's weight is not rocket structure holding the propellant nor other parts of the rocket. By weight, a rocket at liftoff is mostly propellant. Some numbers - a typical passenger jet plane may be 30% propellant, in this case jet fuel, and 70% aircraft, by weight. For comparison, a rocket may be in the range of 85% propellant and 15% rocket, by weight. This 15% does not make for an easy design that will be robust and can focus well on affordability, ease of operation, reliability or safety. At 15% of something to hold 85% of something else, the preoccupation is mostly on getting off the ground, and if need be return, such as with the Space Shuttle. Expendable launch vehicles do not significantly depart from this basic reality. Separating and dropping stages during ascent is simply a means of discarding structure that is no longer required for the rest of the ride, but which was still just as fragile and weight limited.

Now imagine some of the oxidizer was taken from the air as the spaceship traveled through the atmosphere. The topic of Rocket-Based Combined Cycle spaceships was explored extensively in the HRST work as to it's effects on affordability of operations, reliability and safety. Potentially, such technology using SCRAM cycles, if the barrier of thermal management and materials both external and internal could be overcome, could get to where an aircraft-like spaceship, taking off horizontally, would be as much as 35% "ship" and *the rest propellant, vs. 15% "ship" today. The possibilities are explored here in the broader context of the effect such technology could have on creating routine, affordable access to space.

*...see the wiki for more on what the term "mass fraction" means...

*...also see the NASP wiki...

1998

Final Reports > An Operational Assessment of Concepts and Technologies for Highly Reusable Space Transportation (HRST), Executive Summary and Full Report (1MB .pdf), by the HRST Integration Task Force on Operations, November 1998

1997

Defining the Parameters for Affordable Space Transportation, Zapata, E. and Dankhoff, W.F., Aerospace America magazine, November 1997

A Guide for the Design of Highly Reusable Space Transportation, also known as just "The Guide" August 29, 1997

Highly Reusable Space Transportation Architectural Assessment Form, April 30, 1997

A Quality Function Deployment Method Applied to Highly Reusable Space Transportation, Zapata, E., Space Technology & Applications International Forum (STAIF), Albuquerque, New Mexico, January 30, 1997

1996

Report on Rocket Engine Life Analysis (15 MB .pdf): The report describes methods to extend rocket engine life, increasing safety in flight as well as reducing operational costs, such as by reducing failures. Additionally, the data provides information on how a future design would avoid having to remove engines from flight to flight, as done currently with the Space Shuttle orbiters.

Advanced Reusable Propulsion Technologies Announcement / Airbreathers, July 1996

HRST Selectees Announcement, May 1996

1995

Highly Reusable Space Transportation, An Advanced Concepts Study, July 1995

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Also see:

Space Solar Power - An Earth to Orbit Challenge

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Website Contact: Edgar Zapata, NASA Kennedy Space Center