As NASA presses ahead with elements of the Constellation architecture, which will eventually include the heavy-lift Ares 5 (above), others argue for a different, more integrated approach. (credit: NASA)

Infrastructure needed for future space exploration

by David L. Christensen
Monday, July 28, 2008

The United States is facing a crisis in its human space program. The huge investments in the Space Shuttle and the International Space Station (ISS) programs are leveling off, but the replacement for the Space Shuttle and the new space exploration architecture plans for future visits to the Space Station and missions to the Moon and Mars (called the “Vision for Space Exploration” or VSE) are still in early development. A “gap” in the ability of the United States to provide human and cargo transportation to and from the ISS is now of grave concern as the fleet of Space Shuttles is reaching the end of its operational life. This type of unfortunate situation has happened before (1975 to 1981) between the end of Saturn-Apollo rocket operations and initial operations of the Space Shuttle.

Several replacements for the Space Shuttle have been proposed over the years. These include the Shuttle II, the X-30 National Space Plane (NASP), the X-33 Single Stage to Orbit (SSTO), Shuttle-C, Magnum, the National Launch System (NLS), and others. Numerous architectural studies and initiatives have also been attempted over the past two decades such as the Space Exploration Initiative (SEI), the Space Launch Initiative (SLI), the Human Exploration and Development of Space (HEDS), the National Aerospace Initiative (NAI), and others. Most of the above government projects (and similar commercial projects as those proposed by private organizations such as Rotary Rocket, Kistler Aerospace, and Kelly Space and Technology) have failed to reach maturity primarily due to inadequate planning, lack of long-term commitments, and restricted budgets.

Issues and concerns

A number of concerns have been raised both inside and outside of NASA about the selected architecture and design of the new space transportation system, Constellation. Typical concerns include deficiencies in performance capabilities and lack of commonality (the diameters of the upper stages and instrument units are decidedly different between the Ares 1 and the Ares 5 versions, and each system requires a different launch infrastructure). The solid rocket motors for the two versions have different sizes, a five-segment unit and a five-and-a-half-segment unit. There are continuing stability and control issues including thrust oscillations in the solid rocket motors, which could result in unacceptable crew vibration environments on Ares 1. Effective life cycle control processes are lacking and extensive and expensive modifications are needed for Shuttle and Apollo/Saturn heritage hardware and infrastructure, including test stands, launch pads, and mobile/crawler equipment. Modifications to the solid rocket motors and the J-2 engine, initially used over 40 years ago on the Saturn upper stages, will cost well over a billion dollars.

After several years of effort, the Ares 1 still awaits a preliminary design review and the Ares 5 is currently undergoing major redesign efforts to help meet the prescribed mission requirements. Current schedules show significant delays in major milestones. The “gap” is increasing and the current plan is rife with technical, budget, and other related risks. Unfortunately, the current NASA approach of designing two different but complimentary space launch vehicles at the same time is having unanticipated design, cost, and schedule consequences. Changes to Ares 1 are affecting Ares 5, and vice versa. In some cases these changes must go back and forth several times before being resolved. The new systems must meet different environmental and performance requirements resulting in further divergence of the designs and additional loss of desired commonality. Most likely, NASA will have to create and maintain two separate and very costly design, analysis, and operational baselines for the life of the two systems. Resistance to design changes and improvements will likewise restrict technology advancements and freeze our space launch capabilities for the foreseeable future.

On a national and international level, several key issues and concerns have a direct impact on current and future aerospace programs, including the Vision for Space Exploration. These include: devalued US currency and unbalanced trade agreements, restraints to international cooperation due to sensitive data concerns, steeply rising fuel and energy costs, negative environmental impacts of fossil fuel combustion on a global scale, an aging workforce and competitive pressures on the aerospace industry, and a critical need for stronger math and science skills in our educational programs. A broader set of global challenges include meeting such basic human needs as adequate food, pure water, and air; development of lower-cost alternative energy systems; reduction of diseases and conflicts; and improvement of health, education, and knowledge at every level.

Needed plan and approach

An integrated effort and unified approach is necessary to help establish a national space strategy and help to define the infrastructure, architecture, and space policy elements required for our future space exploration programs and related objectives (such as establishing space outposts and settlements throughout the solar system). This broad approach needs to encompass a number of requirements and satisfy the scientific and technological interests of the American public, the security and defense needs of the nation, and support the commercial objectives of private organizations wishing to capitalize on the tremendous resources available in space (including the Moon, planetary systems, asteroids, etc.) Large investments made by the private sector, primarily for communication, observation and navigation satellites, and space tourism enterprises already rival the space-related expenditures of government agencies such as NASA and NOAA. Any government expenditures applied to the development of long-term space infrastructure projects should realize numerous ways to benefit from the investment.

Infrastructure and facility expense is a major factor in overall life cycle costs of large operational systems such as Constellation. Unfortunately, a common and effective life cycle control process is sadly lacking on most large government programs, especially on the Space Shuttle, the International Space Station, and most Defense Department weapon systems. Huge cost overruns are the rule rather than the exception and this greatly restricts the development of new technologies and the advanced systems needed for the future.

We need to rethink and revisit our near-term and long-term planning for constructing a pathway to the stars. The exploration and systematic utilization of the vast resources in the solar system, and beyond, is the manifest destiny of mankind. To achieve this lofty goal, a comprehensive strategic plan is urgently needed. It should include the phased development of key infrastructure elements required to make this possible. NASA has attempted to initiate this effort on behalf of the VSE, but on a limited basis.

We need to establish a broader set of space mission interests and requirements based on overall national goals—not just those perceived by the NASA—and carefully identify the existing and planned space program capabilities that could relate to this unified need. We also need to establish independent advisory and review teams that could help to ensure that the national plan reflects a sound basis for achieving national goals and which is not swayed by regional and shortsighted special interest groups.

We should attempt to more effectively utilize the operational space transportation system capabilities represented by the large Delta 4 and Atlas 5 Evolved Expendable Launch Vehicles (EELVs). Derivatives of these proven systems could be used to launch space capsules or even reusable lifting body spacecraft to orbit. The Redstone Mercury, the Atlas Mercury, and the Titan Gemini were quickly modified from military launch systems and pressed into duty as human space carriers. The Saturn 1 test vehicle was initiated by the Department of Defense Advanced Research Projects Agency (ARPA) before it became the flawless Saturn 1B that initiated and completed the Apollo missions during a nine-year period (10 completely successful flights occurred between 1966 and 1975). Upgrading operational missiles and test articles has proven to be a successful method to gain reliable access to space and should be strongly considered at this time. Our proven Delta and Atlas rockets represent a large national investment and a valuable resource that needs to be incorporated into our space exploration plans. We should also carefully review and evaluate both expendable and reusable launch vehicle systems before selecting those that most effectively apply.

Shuttle-derived vehicles (such as the Shuttle-C) were investigated by NASA and its contractors over the past quarter-century. A variation of this concept could be introduced as the shuttle is phased out of operation and could use much of the same infrastructure and elements (external tank, four-segment SRBs, Space Shuttle Main Engines, manufacturing, test and operational facilities, KSC launch crews, etc.) This would not only ease the five-year “gap”, but would retain very valuable resources that may otherwise be dispersed.

A simpler and more cost effective approach is needed, one which incorporates inherent features of commonality, robustness, flexibility, growth potential, and a true “building block architecture”. Life cycle cost assessment and control must be a mandatory feature of any selected system. One potential system design, called “MAX”, has been proposed that uses a common core and available EELV and Space Shuttle elements to meet mission requirements for the ISS, lunar, and Mars exploration (see the AIAA 2005-4181 technical paper for a description of this concept). Other candidates should be identified and properly evaluated for consideration.

With the current and anticipated national and international conditions, it is difficult to keep a flexible and affordable approach within any large-scale planning effort. It is also difficult to evaluate various options and develop fallback plans to meet a host of unexpected situations and conditions. And it is wise to carefully consider the negative impacts that can accrue from making bad decisions. Any government-funded program must be accountable to the customer, in this case the American public, and should incorporate the best available talent and skills in ways that will maximize the probability of success. This case for the development of a viable and comprehensive strategy, and related infrastructure elements needed for our exploration of the cosmos, is also a plea to do it correctly.

David L. Christensen has 55 years of experience in missile and space programs and has worked with several major aerospace organizations until his retirement in 2005. He worked with the von Braun team and was the Saturn H-1 rocket engine Project Engineer. He is an Associate Fellow in the AIAA and past Chair of the National Space Club - Huntsville and the Space Propulsion Synergy Team. He currently provides consulting services to government and industry.

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