THE SPACE SHUTTLE - MY OBSERVATIONS
By Bob Thompson NASA Shuttle Program Manager 1970-1981
The recently retired Space Shuttle Program has been on the human spaceflight stage for the past 40 years. It is probably too early to establish or comment on its historical place in the evolution of man’s venture into this vast region that we call Space. However some observations may be of value at this time. Personal observations are always biased to a certain extent and one never has all of the facts. We must accept these limitations. I was closely associated with the initial phases of the program and offer the following observations in a constructive intent to be helpful in this time of transition.
THE SYSTEM
The Space Shuttle System emerged out of a loosely focused 6 year planning effort led by NASA with contracted engineering and program planning support from the U.S. aerospace industry. The time period was from 1966 until 1972. Prior discussions by space visionaries were not constrained by real world considerations of cost and practicality and many wild speculations appear in the cartoon history of spaceflight. Who first sat around an open fire pit and visualized man flying into space in various vehicles has been lost in history. Many NASA studies prior to this time were primarily conceptual renderings. The loosely focused nature of free thinking can be valuable.
However by this time we (the U.S.) had progressed thru the Mercury and Gemini programs and had established the Apollo system configuration as the solution to the initial lunar landing and return objective. These programs had to live in the real world of weight, thrust, control, cost etc. They had each fulfilled their program objectives by taking maximum advantage of throw away staging and capsule type earth entry vehicles. These systems worked quite well and were successful with most program objectives met. Cost is relative and by 1966 the annual funding allocated to NASA had grown to nearly 5% of the nation’s total spending at the federal level. Both the Executive and Legislative branches considered this too high for the Agency when overall National needs were considered. Annual funding includes all NASA activity. There was a majority opinion to continue manned spaceflight evolution after fulfilling the Lunar commitment but at a significantly lower annual budget level. The acceptable support level was left open for future discussion by the Johnson administration in 1966 but it was to come down from the 1966 peak. From 1966 to 1970 NASA concentrated on Apollo and Skylab, brought the budget down and left future program planning in what was known as Phase A (Concept phase/ free thinking). Skylab was not considered a traditional program in the sense that it was scoped to effectively use residual hardware from Apollo and was limited to the three planned manned missions. The Skylab workshop was not designed for use beyond this planned visit by three crews staying about 1,2, and 3 months respectively.. Future program planning beyond Skylab converged on the Shuttle and a Modular Space Station in low earth orbit as the evolution objectives to follow Skylab. The annual funding level was still to be discussed. The Shuttle concept that emerged from Phase A was to improve cost thru reusability and improve on earth return with a runway landing. The orbiting vehicle was to have significant space work capability and a wide range of potential uses. It was an enabling system that would certainly improve our manned space capability and support the assembly of modular Space Stations and other applications in earth orbit. It could also assemble vehicles for missions beyond low earth orbit. It was to be the first step in an expanding space transportation system and provide for traveling to and from low earth orbit with useful payload and crew. In 1970 senior NASA management decided that the Agency was ready to enter Phase B with the Shuttle. Plans for the completion of Apollo and the utilization of residual hardware for Skylab were firm. Major program planning would be directed toward low earth orbit and a long term fully reusable concept was to lead to the configuration used to establish a set of detailed program plans. This two-stage fully reusable configuration was the decision from the Phase A effort with some specific lower order design issues such as wing sweep and earth entry energy management unsettled. With the move to Phase B a more focused effort was required. A program office was established at NASA headquarters and project offices were established within the three NASA centers. The thinking at this time was that this first vehicle program in the major evolution step after Apollo was to be the Shuttle and the two-stage fully reusable configuration would fit the Apollo model of center assignments. JSC would manage the Orbiter development, MSFC would manage the fly back booster development and KSC would manage launch support. Everyone was anxious to move forward. At this move to Phase B, I was appointed as the Project Manager responsible for the day to day activities at JSC in support of Shuttle and reported in a program organization headed by the NASA Headquarters Shuttle Program Manager, Charley Donlan. Similar center level project offices were located at both MSFC and KSC. The first order of business for this new program organization was to issue an RFP for Phase B design studies for the chosen configuration. This was accomplished in a timely fashion and two Phase B study contracts were awarded. Rockwell to be managed by my office at JSC and Mc Donnell/Douglas to be managed by the MSFC Shuttle Project Office. Each contractor was to perform preliminary design and manufacturing planning for the complete two-stage fully-reusable configuration and the project offices were to report results to the Program Office in NASA Headquarters. In addition to the two study contracts awarded it was decided to award level of effort contracts to the other interested contractors in order to keep them in the game for the larger development contracts that would be forthcoming. Grumman was assigned to my office as one of the level of effort contractors. By late 1970 we were underway with Phase B, the preliminary design and program planning phase of the two-stage fully-reusable configuration chosen during Phase A.
Shortly after I was assigned as the JSC Project Manager I opened a dialogue with Charley Donlan and began to question the wisdom of the decision from Phase A relative to the configuration. The capabilities required for the system were appropriate for this point in our manned spaceflight evolution and were completely satisfactory to me. However the full-reusability decision was very troubling. Carrying the propellant internal to the vehicles, developing two large complex manned systems at the same time and flying them thru their planned flight regimes seemed to me a bad choice. Charley was a very capable engineer. We could communicate very effectively by phone. He listened patiently to my arguments and we arrived at a very satisfactory approach at the time. I would keep Rockwell focused on the fully reusable system in sync with MSFC project direction to McDonnell-Douglas and I was free to direct Grumman as I pleased in their level of effort support as long as I met our desire to keep them knowledgeable for the forthcoming development phase. With this agreement we directed Grumman to study the effect of putting the rocket engine liquid propellant in throw away tanks starting with the orbiter. Phase B continued thru 1970 and most of 1971 focused on the fully reusable system. We managed the alternate partially-reusable configuration evaluation by Grumman in a non-disruptive manner.
As the two development centers (MSFC/JSC) proceeded with their contractors on the Phase B design work, headquarters would collect the results and negotiate with their Washington interfaces in both the Executive and the Legislative branches of the government seeking approval to proceed into the development phase of the program. About half way thru the planned Phase B period, it became clear that this approval was in jeopardy. By this time the NASA annual budget was down to about 2% of the nation’s budget and a sustainable level had not been agreed on. A strong minority voice was emerging in the Senate against manned spaceflight and the Nixon Administration was facing tough budget choices. The fully-reusable system required the start up development of two large manned vehicles at the same time and the required annual funding forced the NASA budget to hold near the 2% or slightly higher level. NASA could not get support at this level.
By this time at JSC we had completed our off line study of a partially reusable configuration featuring a throw away tank and had budget projections that Washington found more agreeable. It is important to recognize that the two systems had the same on orbit capability. Putting the rocket propellant in an expendable tank and operating the orbiter engines at lift off reduced the staging velocity considerably such that low performance solid propellant boosters were adequate. This allowed time spacing of the development periods required for the various flight elements such that the yearly development costs in the program never exceeded 1 billion dollar. (We were budgeting with 1971 dollars). This allowed NASA to assure the Administration that it could target its annual budget at 1% or less and go forward with Shuttle development as a formal program. President Nixon decided that if NASA could get its budget down to 1% or less and build and operate the Shuttle we had a deal. He made it clear that Space Station was not a part of the deal. That decision could come later by another Administration at a budget level of its choice. With this milestone, which occurred early in 1972, we quickly finished our extended Phase B work targeted toward the expendable tank configuration. Grumman had been very helpful in evaluating the expendable external tank configuration. Mc Donnell Douglas provided the analysis that led me to accept and recommend the solid propulsion boosters.
It was then decided by NASA Headquarters that the next Phase of the Shuttle Program would be managed on a daily basis out of JSC and that I was to be the Program Manager reporting to a Program Director in the office of the Associate Administrator for Manned Spaceflight. I immediately set about creating a program organization and preparing a Phase C/D request for proposal to release for contractor bidding to build the orbiter and support system engineering and integration. A contract for engine development had been released earlier and won by Rocketdyne. The tank and booster rocket developments could be delayed to a later start and keep the budget under control. I decided that NASA had the necessary talent to integrate the program with suitable contractor support from the contractors having responsibility for manufacturing the vehicle elements. Major integration support would come from the contractor building the orbiter and minor support from the engine, tank and booster contractors. All contractor direction would come from the designated NASA project office or program staff office. All major design decisions were finalized by the designated NASA program or project office. NASA retained the responsibility for system engineering and integration of the vehicle and the program. NASA also retained close control of software development and the critical flight control system. We decided that the location of the major avionics development laboratory would be at JSC in order to facilitate long term program support. The engines were to be controlled by their own computers with minimum interface with the orbiter computers. These and many other implementing decisions were made and by late 1972 we had selected Rockwell as the contractor to build the orbiter and to provide major support to system engineering and integration. We were under way with the design, development, test and evaluation phase of the program and looking forward to first orbital flight. A few years ahead but in a stable program plan.
Observation: A very reasonable configuration and program evolved and served the nation well.
Budget
A few remarks on budget: We at my level had estimated that the Design, Development, Test, and Evaluation ( DDTE) phase of the program for the expendable tank configuration could cost 5.15B$ in the purchasing power of the 1971 dollar and that first flight could occur in NOV. 1979 if we were perfect. We also said that it was not prudent to expect perfection and that the DDTE phase of the program should expect to cost 6.15B and get to first orbital flight 18 months later. We felt that it was prudent to plan optimistically and expect problems. The DDTE budget included cost for the first 4 orbital flights. Flight cost after this was to be contained in an operations budget. (An observation). This budget information was passed from my level in the program to my Washington interfaces. We were subsequently informed that the program would go forward with a DDTE budget of 5.15B and a first orbit flight date of Nov. 1979. The 5.15B was placed in the federal budget in 1973 dollars. My attempt to find out what happened to 1B$, 18 months of time, and two years of high inflation were unsuccessful and I was willing to continue as Program Manager. Overrun criticism could be dealt with as it develops. Unfortunately the budget terminology of operations after 4 flights was badly interpreted several years later as a safe shift in vehicle risk maturity. These were unintended consequences: I should have anticipated a misuse of “perfect” program estimates and vehicle risk cannot be derived from budget terminology.
Observation: The development program was successfully completed slightly under the 6.15B projection and first flight came slightly less than 18 months after the Nov 1979 optimistic planning date.
Observation on configuration: The relatively free environment of NASA Phase A planning led to a much larger, probably more complex configuration with a higher development cost than was supportable. The useful work capability of the two configurations under discussion was the same. The Phase A configuration was assumed to be “low” in operating cost due to full reusability, and it appealed to the NASA organization. Each development center had a moderately independent vehicle to build similar to our Apollo experience. Had funding support been provided, a successful program might have ensued at a lower cost per flight. The development cost was certainly going to be higher by at least a factor of 2 or3. It is my opinion that both the cost of ownership and the cost per flight would have been higher with the fully reusable configuration. I have doubt that the development program with that Phase A configuration would have succeeded. I feel that we shifted to the correct configuration during our Phase B studies independent of development cost. The budget pressure and the availability of a suitable alternate configuration led to a successful vehicle development and 30 years of useful flight.
Manned Spaceflight Evolution and the Shuttle Program:
I often refer to the Shuttle as an enabling system to draw attention to the versatility and capability of the configuration that was chosen. The propulsion elements were arranged such that the Orbiter elements forward of the three main rocket engines could be readily replaced with a cargo carrier having significant capability. In the initial planning for the Shuttle program this possible arrangement was referred to as Shuttle C. Shuttle C was not pursued very far in the 1970 time period since the Shuttle and the modular Space Station needed to come first in an evolutionary sense. My observation: The enabling potential of the Shuttle configuration was lost during the 30+ years of Shuttle/Space Station evolution. After the second Shuttle accident confidence in the system was at such a low point that termination was allowed to proceed without responsible evaluation. NASA was a willing spectator.
Cost of ownership
How to evaluate the value of the Shuttle to the nation is a challenge. We see a lot of discussion about cost per pound of payload to orbit and the Shuttle being too expensive on this basis. This is a poor parameter to attempt to use in determining the value of a system like the Space Shuttle. What is important is the value of what it does and is it affordable on an annual budget that is sustainable. The Shuttle fit comfortably within a NASA annual budget of 1% or less of the nation’s budget for 40 years and enabled additional steps in the evolution of manned spaceflight. Hubble and Space Station are two examples of the evolution during this period. We have truly been a space faring nation since Apollo within an affordable cost of ownership. The perception that the Shuttle was too costly and risky should have been corrected. We should have been more thoughtful about how to evolve our manned spaceflight capability within a cost of ownership consideration.
Risk
How to evaluate the risk that the Shuttle entailed is also a challenge. The two fatal accidents contributed significantly to the perception of risk and hastened the desire to move on to a “safer” system. Safety is most often accepted as the gain/risk ratio and what the so called safer system does must be considered. It is my observation that current thinking favors the need for a separate launch escape system and a capsule/parachute earth entry configuration. This attempt to lower risk may become counterproductive to an evolving capability and should be carefully reevaluated. In this same issue of risk we seem to want to require a direct return to the earth surface from all regions in space occupied by humans. This will also be restrictive to our evolving move to deeper regions in space. The Shuttle experience will contribute to these considerations perhaps in an unfortunate way. The failures that led to the two Shuttle accidents should be carefully reviewed and objectively understood. The design weaknesses that led to the accidents are typical of the issues that must be corrected during operations in any complex flight system.
In summary my looking back observation is that the Shuttle configuration was a wise choice. The enabling capability that was used gave us a productive 30 year flight activity. The enabling capability for beyond earth orbit flight support was not properly understood by evolving management and essentially destroyed by the two fatal accidents. The decision to retire the Shuttle system made in 2004 by the Bush Administration and subsequently upheld by Obama Administration caused a radical shift in our manned spaceflight evolution path. Where we go from here is unclear at present. The shift to “commercial” for low earth orbit operations may prove beneficial and history may well record this as a wise move at this time. How to approach travel beyond earth orbit is currently vaguely directed toward an asteroid visit and a possible Mars fly by at some future date. We have embarked on a high cost high risk of cancellation program to develop SLS/Orion without a proper understanding of what we intend to accomplish. The so called “Flexible Path” discussion from the Augustine study directed by the current Administration may have value in providing guidance to research activities but does not give adequate focus for formal program planning. Before entering the high cost phase in any program you should have detailed plans on what you want to accomplish and a fair idea of when. Budget support is vital.
Modular Space Station
In the transition from Apollo to Shuttle a major consideration was the approach to a long term Space Station configuration. After much debate a modular approach was chosen and the desired modular size helped establish the payload bay size for the Shuttle. Modular assembly on orbit drove many of the capability features of the Shuttle. The modular Space Station approach was a wise choice.
Why was the program terminated?
My best summary of why the Shuttle program termination was announced in 2005 by President Bush and allowed to occur in 2012 by the Obama Administration would have to combine several factors. No clear rationale for termination was ever given by either the Bush or Obama Administrations that spanned the 7 year phase out leading to the final flight in 2011.
The Bush Administration announced in its “Vision for Space Exploration” that the venerable Shuttle would be terminated at a future date (2010) and that we would embark on a Lunar/Mars program. This Lunar/Mars program decision was not well thought out and proved to be a folly. It spawned a program called Constellation that expired due to poor engineering, poor planning, poor execution and lack of funding support. It was properly cancelled by the Obama administration but pieces linger on due to confused support by the Congress and the Obama Administration.
Clearly the two fatal accidents led to a perception that the Shuttle was unsafe. Most discussion of cost led to the perception that the Shuttle was too costly. The chronological age of the system led to a perception that the Shuttle was too old. These loose perceptions were never properly responded to by NASA. In fact they were instituted by many key NASA officials. For example when Mr. Griffin became the NASA Administrator he quickly proclaimed that the Shuttle and Space Station were a mistake and he was here to correct this mistake. He promptly wasted about 12 Billion dollars and five years. Therefore perception became fact and the Shuttle program was allowed to fade away gracefully over several years with no responsible study as to why. The Nation quietly found its self without a means for launching people into space. Depending on the Russian Soyuz system was the only option available to continue manning the Space Station.
The “Vision for Space Exploration” announcement by the Bush Administration following the second Shuttle accident and the confusion left by the Columbia Accident Investigation Board essentially set the country up for an inadvertent “Bait and switch” situation. Let’s terminate the venerable Shuttle, go back to the moon with an Apollo type throw away system and on to Mars. We can do this within current budget levels. Once the bait was taken the Shuttle was allowed to terminate and the idea of” Apollo on Steroids” disappeared. We are now in a “Down Time” and can hope for commercial to get us back in the space business with some limited capability. This so called “commercial” program started by NASA during the Bush Administration and wisely continued by the Obama Administration should be encouraged and properly supported. It is now May 2012, 42 years after establishing the Shuttle Program as a formal NASA endeavor. We are temporarily out of the manned launch business.
We need an Administration that can plan to use our available Space budget wisely. We should continue with commercial and carefully review the reasoning behind SLS/Orion. The budget level for NASA and all high cost program efforts need careful Executive and Legislative Branch understanding. NASA’S Manned Exploration Program is not effectively planned.