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Space Transportation Systems "-ilities"

Affordability, Reliability, Safety, Maintainability, Operability, Complexity, Sustainability & Responsiveness

Understanding the Pieces

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Design for Operations - "D4Ops"

It is envisioned that dramatically safer, lower cost, and higher flight rate access to space is possible by applying the wealth of experience gained from human space flight launch operations. Shuttle launch operations, particularly the world’s only reusable space plane elements, the orbiters, have accumulated a vast set of ideas, lessons learned, insight and “design for ops” experience. Current work such as the Shuttle Root Cause Analysis will add further insight to quantifiably understand why previous reusable launch systems are as costly as they are and why they take as long as they do to prepare for launch.

"Designers of space launch systems should be cognizant of the impact of their design assumptions on operational characteristics. Operational metrics such as turnaround time, recurring cost, and headcount are critical factors for the future viability of such systems. The results presented here are from a study that seeks to determine in what manner design approaches can improve the operability of future space launch systems. This is accomplished by applying such operational approaches at the start of the concept design process. These design for operations (D4Ops) choices or approaches are determined from data-mining NASA Space Shuttle orbiter processing information. These approaches are then applied to three different launch vehicle contexts created for this study and based on existing NASA reference designs. These contexts include near (2010), mid (2015), and far (2025+) term examples. Specific lessons about the D4Ops approaches, as learned from the first two examples, are then applied to the far term context. Weighted rankings of the impact of these approaches on various metrics of interest are provided."


Sustainability: Competitiveness, Economics, Business and Acquisition Models

"Air Mail Act of 1934 - Aerospace history can provide us some inspiration on this subject. The air transportation world in the early 1930s ran into the ethical problems that can often occur in completely vertical business arrangements with a narrow set of players. The issue was finally resolved through anti-trust legislation in the Airmail Act of 1934."


Maintainability, Space Shuttle Thermal Protection Systems (TPS)

  • The following file on Shuttle Orbiter Thermal Protection Systems (TPS) maintenance contains data that is extremely valuable to operations analysis such as relates to maintainability for one of the many complex systems on a reusable space transportation systems element. It is one piece of a much larger set of issues, including safety and reliability, relating to TPS systems, current and future. The CAIB report, coupled with the data herein, demonstrates how systems such as RCC can appear robust, but still be both un-safe and difficult to maintain, having an ill understood set of failure modes that can contribute to a low overall reliability/safety/operability. DATA: "The Cost of Maintaining Thermal Protection Systems", by Frank E. Jones, NASA Kennedy Space Center.

And from the CAIB report, page 83:

"The wing leading edge Reinforced Carbon-Carbon composite material and associated support hardware are remarkably tough and have impact capabilities that far exceed the minimal impact resistance specified in their original design requirements. Nevertheless, these tests demonstrate that this inherent toughness can be exceeded by impacts representative of those that occurred during Columbia's ascent."


April 23, 2004

While scheduling a series of launches results in a plan that is worked to, system reality involves uncertainty, variability, and randomness. The long-view question becomes not "when are we planning to launch", or "how many launches are we planning for any year". The long view asks "what are the chances we will launch by a given date" or "what are the chances we will achieve a given number of launches by a set time in the future".

"Prediction is very difficult, especially about the future." Niels Bohr, Danish physicist (1885 - 1962)

The Process for Simulation Modeling and Analysis of Space Shuttle Manifest Options

Shuttle Launch Pad Operations Added Work Days Post the Delta Launch Site Flight Readiness Review



Safety, Reliability, Space Shuttle Thermal Protection System (TPS)



  • DATA: The Rand Study -"Report of the Space Shuttle Competitive Sourcing Task Force" was released December 2002. Updated cost data on the Shuttle program is detailed in the reports.


  • "Dr. Kurt H. Debus: Launching a Vision", C. McCleskey, NASA John F. Kennedy Space Center and D. Christensen, Lockheed Martin Space Systems Company, International Astronautical Federation (IAF-01), Toulouse, France, October 2001. Download (3MB .pdf).



Operations Analysis Tools - Surveys

These documents are the result of surveys into government, industry and academia in search of data, tools, software or capabilities applicable to the field of space transportation operations cost/time analysis and assessment.

The unique issues of space transportation operations estimation, especially in the early phases of design and development, are a common theme in these surveys on tools available within and outside of this aerospace community.

  • 2001: "Baseline Comparison System", July 17, 2001 - A review of reliability, maintainability and supportability (RM&S) data by Jeff Morton & Mike Nix of Marshall Space Flight Center (MSFC), with contributions From Doug Morris and Richard Brown, Langley Research Center (LaRC).




Reliability, Operability, Space Shuttle Main Engine (SSME)


For future systems to improve on the Space Shuttle it is extremely valuable to analyze and understand the Shuttle operations experience qualitatively and quantitatively. One such report follows specific to the Space Shuttle Main Engines (SSMEs).

  • NASA/TP—1998–208530, "Reusable Rocket Engine Operability Modeling and Analysis", R.L. Christenson and D.R. Komar Marshall Space Flight Center, Huntsville, AL. Download (.pdf)

All the "-ilities".



Reliability, Maintainability, Ground Operations, Rocket Engines

This report describes methods to extend a rocket engines life, and to reduce failures, thereby reducing operational costs and increasing flight safety. Additionally, the analysis shows a way to avoid having to remove engines from flight to flight for future reusable systems, as done currently on Shuttle orbiters.


Maintainability, Space Shuttle Thermal Protection Systems (TPS)

For future systems to improve on the Space Shuttle it is extremely valuable to analyze and understand the Shuttle operations experience both qualitatively and quantitatively. The Shuttle Thermal Protection System (TPS) experience is one such example.

Reliability, Safety

  • "1995 Probabilistic Risk Assessment of the Space Shuttle, A Study of the Potential of Losing the Vehicle During Nominal Operation". Download (6MB .pdf).

1993 - 1994

These files date back to 1994 and the work of the Operations Synergy Team. This predates the selection of Lockheed-Martin to build the X-33. The files are still very relevant to future technology pursuits and space transportation systems affordability.


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Website Contact: Edgar Zapata, NASA Kennedy Space Center