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Battle for the space shuttle (18): the aftermath
the space shuttle ghost
Big Gemini will fly a maximum of four missions a year. There's no way of ramping up flight rates above that level – the bottleneck is the Titan III launcher. At least a space station is being build.
Reading the leaked Matematica report however one can't help daydreaming about the lost shuttle. The morale might be, NASA gambled a lot and ultimately lost. It should be remembered that, as of 1971 per lack of budget NASA went as far as killing the space station, betting everything on the shuttle itself.
Per lack of space station, a tin can laboratory would have been flown within the shuttle payload bay. At first glance that looks like a dubious substitute to a space station, but in fact it was a long-thought gamble. With the lab in the payload bay the shuttle tookover a good chunk of space station missions, and that inflated its flight manifest artificially.
It should be remembered that NASA sought to earn money when flying the shuttle; and to achieve that, the shuttle had to fly a lot, as much as once a week. The more missions the lower the cost - that was the motto. More generally it was hoped that low cost of space transportation to orbit would help creating new missions, closing the shuttle economic case. With perfect hindsight is was a risky, but audacious, bet. We will never for sure whether it would have paid or not – at least not until a successfull atempt at a RLV is made in the future.
FLIGHT International. 29 August 1974
By DAVID BAKER
Recently a disgruntled economist with the name of Klaus Heiss leaked an economic study he had done of the now defunct space shuttle. That study has been the subject of intense controversy. Some see it as a glimpse of a forever lost era – how the shuttle would have flown a lot, turning the usual space launch business upside down. Others said it was just outrageous – the the numbers touted were utterly naive and unrealistic. Taking the Mathematica study as a point of departure, David Baker picks up an interesting angle – that of counterfactual history. He tries to imagine where woud we be had the shuttle not been cancelled three years ago.
Now that the space shuttle is well under way the technical barriers are coming down and confidence is backed with an enthusiastic optimism for the golden age of cheap commuter travel between Earth and near-space. Just three years ago the much publicised Space Station, a follow-on to Skylab, began to price itself out of future plans and the container method came in.
By packaging several instruments together and mounting them on a pallet, the Shuttle's own cargo bay will serve as the platform from which scientific tasks may be conducted, so capitalising on the enormous ready-made volume built in to the Orbiter. If men are needed to tend the equipment a cheap, pressurised compartment can be carried alongside. This, in essence, is Spacelab, and flights using this European-built laboratory will be called Sortie Missions.
But the Shuttle is not an end in itself and even with Spacelab in the cargo bay it will realise only a small part of the ambitious programme now envisaged for it. To effectively plan a space programme for the 1980s Nasa has built up a Mission Model, using proposals for the use of satellites or spacecraft as a yardstick from which the payload priorities over the next decade and beyond can be determined.
An earlier plan developed in 1971 foresaw 327 possible payloads in a 12-year period and the present model raises this to 507 as a result of cancellation of the Space Station. This is naturally more cost-effective because of the increased launch rate. Non-Nasa Government agencies, private consortia and possible European payloads add a further 173, while the Department of Defence estimates that it will require 304 payloads to be flown into orbit.
Because the Shuttle will be capable of carrying more than one payload per flight the 986 packages can be condensed into 725 flights in the 12-year period between 1980 and 1991. Of this total Nasa will launch 501, or 69 per cent.
The Mission Model is best analysed by dividing it into Sortie (Spacelab) flights and direct-launch missions, in which a satellite is put into orbit or "retrieved. About 34 per cent of all Shuttle flights will use Spacelab, and less than half of these are expected to use the unmanned pallet alone (i.e. without the habitable pressure module). Only 12 per cent of Spacelab flights are devoted to non-US payloads, while US commercial users account for 3 per cent and Nasa for 85 per cent. Thus 34 per cent of all Shuttle flights support 69 per cent of the payload envisaged. The remaining 31 per cent of Shuttle payloads will be direct-launch satellites encompassing Earth-orbit, deep-space and planetary objectives.
But the Shuttle has limitations on performance and not all the anticipated payloads can be launched by the Orbiter alone, although some flexibility exists for tailoring the Shuttle to specific payloads. Normally the Orbiter will carry 23,8801b of propellant, sufficient to provide a l,000ft/sec velocity change for manoeuvring purposes from the two 6,0001b-thrust engines mounted in the rear fuselage.
These rocket motors will be used to provide the final boost into parking orbit, to circularise the orbit at a desired altitude, to provide the energy needed for all orbital changes, and to de-orbit the craft at the end of the mission. Flights from the Kennedy Space Centre, from due east up to 55° inclination require less than 150ft/sec velocity change to reach a 50 x 100 n.m. orbit, while a launch from Vandenberg AFB, 55° il04° inclination, needs 350ft/sec to reach the same orbit after mainengine cut-off. This allows the big propellant tank to fall back to the atmosphere without the need for a retro-rocket. Polar flights are heavily penalised by the increased velocity demand, and these are reflected in the payload figures.
In basic form the Shuttle will be capable of placing a 65,0001b payload in a circular 28-5° orbit at 210 n.m. altitude. With the same payload it can attain a 450 n.m. apogee from a 100-mile orbit. For a 90° orbit the payload is reduced to 35,0001b, the altitude falls to 200 n.m. and the maximum apogee available is only 390 n.m. These figures represent the best trade-off between altitude and payload, although weight changes have only a marginal impact on the orbit and the absolute altitude attainable is relatively insensitive to off-loading from the cargo bay. This is reflected in the payload figures for the 28-5° orbit; whereas 65,0001b can be carried to a circular 210 mile path, reducing the payload weight to 1,0001b raises the altitude by only 75 miles.
To reach higher orbits the Shuttle can be fitted with up to three supplementary fuel tanks fitted in the cargo bay and fed to the two manoeuvring engines by means of additional plumbing. With all three tanks installed the Orbiter gains an, extra l,500ft/sec manoeuvring capability over the l,000ft/sec available by using the integral tanks. This permits the Orbiter to deliver 25,0001b to a circular, 585-mile orbit at 28-5° inclination, or a 1,040-mile apogee from a 100-mile perigee. But even this is too low for many of the payloads proposed in the current Mission Model, in which 43 per cent of all flights require a supplementary method of propulsion. In fact, 17 per cent of all Nasa and DoD missions involve synchronous orbits and this reflects a dilemma of the entire programme.
For several years the Shuttle was seen as a cheap economic launch vehicle, carrying scientists destined for large orbital laboratories and piloted by a cadre of astronauts, ferrying massive supply containers to the permanent Space Stations. The demise of the Space Station has given predicted launch rates a boost, as noted earlier, by transferring orbital laboratory experiments into the Shuttle itself. However the economics of Shuttle launch operations can no longer be regarded as a challenge to the existing family of expendable rockets. This is due both to relatively high launch costs compared with small rockets such as Scout and Delta, and in the higher percentage of flights needing orbital altitudes in excess of those attainable by the Shuttle. The extra propulsive stages needed for these flights cannot be regarded as payload, but must be chargeable to the Shuttle. To do so would be tantamount to classifying the Saturn V third stage as part of the Saturn's payload. Because of this the launch cost per lb of payload weight increases well beyond the $160 obtained by dividing launch cost by maximum payload. In fact, several flights indicate a financial disadvantage in using the Shuttle.
An example of this reasoning is illustrated by the proposed 1986 Mariner-Uranus mission. Although the weight in the cargo bay exceeds 46,0001b the actual spacecraft weighs a mere 2,1371b. Two launch cost figures can be deduced from this. If the entire contents of the cargo bay are charged as payload the launch cost per pound of payload weight comes to $218. If, however, the Mariner spacecraft alone is deemed to be the payload then the launch cost is $4,560/lb payload.
This is an extreme example but it serves to show the influence of an additional propulsive stage in the Shuttle. The Mission Model referred to earlier indicates how effective the Shuttle can be if used for only those missions where a heavy payload is required. For example, Nasa forecasts 14 Shuttle flights into near-Earth orbit in 1980. The average load on each flight will be 25,0721b and since all of this is payload the launch cost comes out at a competitive $36.1/lb payload weight.
Taking another 12-month period, 1983 for example, Nasa expects to mount 40 flights and the picture here becomes very different. The Mission Model anticipates 27 direct Shuttle flights and 13 missions involving the use of an additional propulsion unit. The average payload weight per flight reduces to 13,9091b and the launch cost increases to $674/lb payload weight. Again, the additional propulsion unit needed reduces the cost advantage over expendable rockets and since a higher fraction of DoD payloads require such a boost the economics become less attractive.
Because the Shuttle can offer many advantages denied to the conventional launch vehicle, such as re-usability, retrieval of redundant or faulty satellites and the return of a propulsive stage incapable of Earth-entry by itself, any evaluation of economics must take into account the entire programme envisaged for the period 1980-1991. Based on the current Mission Model, accommodating 986 payloads on 725 Nasa /DoD flights, the Shuttle programme would cost $49,370 million at 1972 prices. Included in this estimate is the need for 80 expendable rockets of the Scout, Delta and Titan classes during the 1980-1982 build-up period. Seven Shuttle vehicles are required to support this Mission Model and the three-year build-up envisages maximum acquisition rates of follow-on Orbiters, so keeping production costs down.
By comparison, the equivalent traffic rate using conventional rockets would cost $63,470 million. The difference between Shuttle and expendable models' shows a gross benefit of $14,100 million during the 12-year period. However, it should be stressed that the expendable rocket model uses criteria developed for the Shuttle, with payloads optimised around the Orbiter. By designing the payload model for expendable rockets in the first place the Shuttle would be hard put to justify its existence. Clearly the new Mission Model is built around the Shuttle itself and this further enhances the argument that not only is Nasa developing a new launch vehicle but also promoting a re-direction of effort in the entire space programme.
As the annual launch rate is reduced, so the economics become increasingly unfavourable to the Shuttle. It is instructive to compare the projected launch weights in the Mission Model with those of the past 12 years. The highest annual Nasa total was that of 1972 when 33,6451b was launched, but the average over the last 12 years has been only 14,0581b per annum. This excludes manned flights since a true comparison must ignore the abnormally heavy weights associated with these programmes of the past. There is no equivalent in current planning for the Gemini/Apollo/Skylab projects and such figures would serve only to cloud the issue. Seen against this past 12-year record are the predicted launch weights for the future and in three typical years taken from the 1980-1991 Mission Model the comparison sets a different pace. Some 351,0001b is to be launched in 1980, 556,3561b in 1983 and 1,052,5251b in 1990. It is this level of effort which generates the $14,100 million cost benefit mentioned above. (DoD missions are excluded from both sets of figures.)
It remains to be seen if Nasa, in concert with other users such as the European Space Agency and Intelsat, can really generate such a busy payload traffic from a relatively static budget.
As we saw earlier Nasa and the DoD will not be able to fulfil all their needs with the present Shuttle performance, even with additional fuel for the two manoeuvring engines. Because of this the USAF is to adapt an existing rocket stage for use with Shuttle payloads from 1980. The Interim Upper Stage, as it is called, will be an expendable booster and will probably take the form of a modified Agena. By 1984 it will be replaced by the Tug (to be developed by Nasa), a more sophisticated propulsion unit capable of dispatching satellites to synchronous or highaltitude orbits, boosting spacecraft to the planets and bringing back payloads to the Shuttle for return to Earth. The interim vehicle arid the Tug will both be made available to customers needing them.
It is too early yet to discuss the design aspects of either the Interim Upper Stage or the Tug—manufacturers are only just starting to look seriously at the concept—but the performance requirements are already defined and this indicates, in turn, the ultimate potential of the first generation Shuttle.
The specification for the cryogenic Tug requires transfer of a 7,0001b payload to synchronous orbit and the return of the vehicle to a 160 n.m. parking orbit. It is then retrieved by the Shuttle, placed in the cargo bay and returned to Earth. If the Tug is on a satellite retrieval mission the down-load is limited to 4,2501b, or 2,7501b on a combined deploy/retrieval flight.
To accommodate these requirements the Tug would be about 35ft long, 15ft in diameter, with a dry weight of 5,2001b and a maximum propellant weight of 55,7001b. The performance calls for a 15,0001b-thrust engine with a specific impulse of 461sec. However, the Tug will not be available before 1984 and the less powerful Interim Upper Stage will not make available anything near this performance during the first five years of Shuttle operations. Even the Tug will not provide the performance needed to meet the requirements for several of the proposed planetary missions. For instance, the velocity increment of 18,000ft/sec needed to reach the outer planets would demand the use of a kick-stage attached to the payload itself. The Tug would propel the spacecraft to a partial escape trajectory, separate and then return to the Shuttle's 160 n.m. orbit. The payload meanwhile would need an additional 6,000ft/sec from the expendable kick-stage to escape from the Earth's gravitational influence. This compromises the economics even more owing to the loss of the supplementary boost stage, which disappears into space along with its payload.
It- is too early to be dogmatic about projected mission models for the 1980s. The existing model, developed by Nasa and the USAF, assumes a static Nasa budget of $3,300 million at 1972 prices but it is difficult to see how the high launch rate can be sustained. For the Nasa flights alone (501 from 1980 to 1991) the Mission Model calls for an average annual outlay of $390 million in launch costs alone. This assumes each Shuttle flight will cost $9-05 million at 1972 prices, with an extra $1 million for each of the 152 Tug flights.
Nasa has consistently attempted to justify the economics of a Shuttle-based space programme on the $5,500 million development figure. But this covers only two Orbiters, and the Mission Model now proposed requires procurement of five more Shuttles at an estimated $250 million each. In addition to this the payload prediction includes 12 Interim Upper Stages, seven Tugs and 16 kick-stages. Development of the Tug alone could cost $1,000 million, excluding additional models. Finally, planning for the Spacelab element envisages five support modules (i.e. the pressurised, manned laboratories) eight experiment modules (cylindrical containers attached to the rear of the support modules, carrying experiments) and 45 separate experiment pallets. In short, a lot of equipment will be needed to support the 986 payloads proposed and it is difficult to accurately predict the effects on the economics of even a minor slip in development schedules
Assuming that the ambitious programme anticipated for the 1980s is a realistic proposition the $14,100 million cost advantage in using the Shuttle for 12 years is going to be offset by the increasing quantity of equipment necessary to support such a venture. Any delay in introducing the full inventory of Shuttles, Tugs, kick-stages and other vehicles now envisaged would keep expendable launch vehicles in business for years. Commercial users such as Intelsat will undoubtedly press vigorously for the retention of conventional rockets, particularly Scout and Delta, unless means can be found to substantially reduce the nearly 2:1 cost penalty of using the Shuttle.
But if these figures reveal anything at all it is that the Shuttle must be seen as an investment in future space capability, bearing in mind the limitations imposed by the phased introduction of equipment. The Mission Model assumes availability of an interim Tug in 1981, capable of re-rendezvous with the Shuttle but not of retrieving a satellite from high altitude. Now that the USAF has pursued the Interim Upper Stage as an expendable unit Nasa will be unable to retrieve satellites above 350 miles until the Tug appears in 1984. Combined deploy/retrieval flights lower this figure considerably. Also, the 12 Interim Upper Stages demanded by the Mission Model assume them to be recoverable. By throwing each unit away for the first five years of Shuttle operations the economics are further compromised.
Clearly, the launch of 800,0001b payload per annum relies on too many factors converging at the right time. The ambitious Mission Model has too* many parallels with the programme proposed in 1969 which envisaged longduration stations in space, lunar bases, lunar orbit stations and nuclear shuttles, to be wholly relevant today. Nasa has to develop and effectively use the Shuttle to survive another decade of space operations, but an over-optimistic attitude has, in the past, left the agency with a string of cancelled projects. Only a realistic attitude to future requirements can hope to reverse this trend.
In conclusion - the Shuttle was hailed as a major technical step forward when it appeared on the scene five years ago, sponsored by a Nasa anxious to keep the huge Apollo industrial machine in being. The Shuttle will undoubtedly have a major part to play in the American and European space programme being schemed for the 1980s, but is not perhaps the total launch vehicle that Nasa appears to consider it. If you have a 65,000lb manned scientific laboratory to place in low Earth orbit, then the Shuttle is just the job. But if you have a 1,0001b communications satellite bound for stationary orbit (and paid for by the shareholders) a good old-fashioned rocket will do the job at half the cost.
PRINCETON ECONOMIST KLAUS HEISS ANSWERS DAVID BAKER CRITICISM OF THE PLANNED SHUTTLE FLIGHT RATE.
- INPUTS TO THE 1972 SPACE SHUTTLE ECONOMIC STUDY
Contrary to perceptions, the case for the Space Shuttle – and also for the Space Tug, then an integral conceptual part of a reusable Space Transportation System (STS) to service to all Earth orbits – was NOT based on transportation cost savings. Important presentations by the independent assessment team in 1970-71 started with the realization that the Space Shuttle cannot be justified solely with the narrow argument of transportation cost savings.
Indeed it is this statement – that the Space Shuttle System could NOT be justified on the basis of transportation cost savings – and the logical exposition of the REAL case for the Shuttle that won the author the award to do the independent outside assessment by NASA in 1970 to begin with. Imagine: a $3 million contract, limited explicitly to five pages of substantive exposition AND a full day cross-examination as to the rationale AND to start out the presentation with the statement: “The reusable Space Transportation System (Space Shuttle and Space Tug) can NOT be justified on transportation costs!”
So what WAS the logic for having a Space Shuttle and Space Tug – other than reducing the cost of Space transportation? The very first Table in our 1971 Executive Summary and our Main Report to NASA clearly and simply stated that the life cycle costs would be less for New Expendable (rocket) systems than for a Space Shuttle and Tug – some $11 billion vs. $12 billion, NOT counting the costs for manned Space flight missions!
However one “massaged” the NASA and DoD mission models (we reduced the mission numbers given to us by the agencies by up to 67%) there was no way to “justify” the Space Shuttle based on transportation costs over a 10-year, 20-year or even “infinite” time horizon – where “infinity” has a way of shrinking drastically when reasonable discount costs are applied to “future” savings, which we did.
The various Shuttle configurations considered in the 1971-72 assessment are shown and compared in terms of total non-recurring costs (RDT&E, initial fleet of five orbiters) vs. the cost per flight of the various options. These ranged from a fully reusable version (A “707” sitting atop a “747” taking off vertically with all internal LOX/LH2 tanks), to Thrust Assisted Orbiter Shuttles (TAOS) and a “Reusable Crew Module” launched on expendables.
Also shown in Figure A-2 is the effect of interest rates on technical system choices: were funding, costs and risks no issue, then a case could have been made for a fully reusable Shuttle. However, given those constraints the TAOS set of configurations emerged as the choice.
The ‘Orbital Space Plane’ was rejected out of hand, as with the intended uses (with a reusable Space Tug) for carrying all payloads to low, high and geosyncronous orbit and the ensuing ‘payload effects’ the basic rationale for the new Space Transportation System was foregone. Also noteworthy in this context was the fairy tale of the “assumed” $5 million cost for each Shuttle launch. The range of launch costs was clearly identified in ALL reports and testimony to Congress and in three separate GAO ‘in-depth’ reviews in the 1970’s
For TAOS with Solid Boosters (the configuration ultimately chosen by NASA) these costs ranged anywhere from $15 million to $30 million (in 1970 dollars – or about $60 to $120 millions in today’s dollars) depending on assumed launch rates of up to 24 per year, with a clearly stated launch risk of 2% (98% success rate).
In contrast, TAOS with Liquid (Pressure Fed) Boosters would reduce these costs and risks by about half – and would permit the possibility of intact abort throughout launch.
Furthermore, moving toward a fully reusable STS (using modular designs with standardized spacecraft components) would open up totally new ways of operating and assuring space missions – collectively called ‘payload effects’, e.g.,
· The ability to revisit any and all satellites in Earth orbit would allow for cost effective maintenance, repair and updating of components of these spacecraft. Transportation costs constitute only one third of total STS costs. The rest has to do with spacecraft, instruments, data and their processing – in space and on the ground
– and a modular design with standardized components offers great benefits in further reducing costs of the other two- thirds of total STS costs.
· Standardization of Spacecraft and Space systems at the subsystem level was a revolutionary idea in 1970 (still unimplemented, by the way) that promised up to 67% cuts in support costs for spacecraft. Standardization would facilitate repair and updating a satellite subsystem level – permitting relatively untrained personnel to exchange blue, green, pink and whatever other color boxes. As in 1970, only a few Space missions are “outside” the scope of such standardization.
· Reliable On-orbit service reducing the costs of required high confidence capabilities of key national security satellites, which is very expensive to achieve through redundancy of expensive satellites.
· In-orbit modernization made feasible by such replacement and repair capability. This prospect of updating expensive satellites in Space at the component level, is much to be desired over replacing whole systems or – worse – letting old technology linger in Space providing obsolete services.
In this context, our 1971-72 study examined both manned and unmanned missions. We did not want to rationalize the Space Shuttle simply and solely on the basis of man in Space: that would tilt the analysis much too much in favor of the Space Shuttle.
We observed that Space Tug and Space Shuttle would open up extensive new capabilities, e.g., structures larger than could be carried by any expendable system could be standardized and designed for on-orbit repair, replacements, updates, maintenance, etc8. We identified entirely new classes of Spacecraft for science, commerce or defense – in Low Earth Orbit, intermediate orbits, and up to and beyond Geo-synchronous orbits. Dozens of new Space application missions where designed and outlined for NASA, the DoD and private enterprise – once the Space Shuttle and Tug were fully operational, e.g., for
Space Science: one of our first visits in Princeton was to the astronomy department, chaired at that time by Prof. Spitzer. The result of these meetings was what today is known as the Hubble Space Telescope. I'm strongly convinced that, had the unique capabilities of the Space Shuttle been available, this magnificent instrument could have been built, launched, repaired, maintained and modernized much more easily – on the ground, not in space !We also defined half a dozen other scientific Spacecraft, some in LEO, some in HEO and some in GEO, ranging from radar to infrared to multi-spectral instruments of a size and capability hitherto unknown and unimaginable.
· Commercial Applications: particularly for communications and remote sensing. Some applications would develop with or without the Shuttle, e.g., a vast range of communications and navigation satellites, including GPS, a variety of Global resources sensing satellites, low and high Earth orbit communication satellites at a variety of frequency bands. We also foresaw an entirely new class of satellites with vastly expanded capabilities, e.g., a new generation of communication platforms in geo-synchronous orbit with vastly increased power- requirements, on-board switching, data processing and storage; tens of thousands of spot beams, and satellite-to-satellite optical and laser communications allowing point-to-point communications to any place in the world. Direct access to repair, maintain and modernize these platforms was critical to providing 99.999-plus reliability. We envisioned a Global Resources Information System (GRIS) described in detail in the NRC papers of the Snowmass meetings of 1974. The effect on the distribution of world food supplies through the commodities markets alone accounted for billions of dollars in annual benefits. Environmental, energy, geologic and other resource observations benefited as well, including such arcane applications as archeology. Many of these have become reality today, as they can also be achieved with smaller spacecraft, not requiring the capabilities of the Space Shuttle and Tug system.
· Defense Applications: at least one-third of all applications foreseen for the new STS were defense related. They included some of the applications realized since then in navigation (GPS), in observations, in communications, albeit not to the extent possible if we had truly developed the full Shuttle and Tug capabilities, with vistas for expanded uses of Space very similar to those cited for commercial uses above. Building on the considerations of “Bambi” and a seminal 1968 paper by Max Hunter – a member of our team – showing the technical feasibility (in principle) of a Space based laser defense against ballistic missile attacks, we included BOTH options [kinetic (Killer Bees) and lasers] in our analyses of 1971-1972
While not necessary for a positive Space Shuttle decision, these possible space missions would have significantly added to the benefits of the STS then proposed.
Not included in the cost-benefit analysis was a vision of future energy supplies from Space to Earth, e.g., large Solar Power Satellite Platforms of up to 100 square miles in area, first proposed by Peter Glaser of Arthur D. Little. One such platform alone will be able to supply up to 10 GW of electric power to any point on Earth. Also not included were any manned Space flight missions such as a Space Station, or Lunar missions or missions beyond. While these possibilities were recognized, we chose not to comingle them with unmanned Space missions which alone justified the Shuttle-Tug STS on the basis of a cost comparison. Their inclusion would open new horizons, indeed.
Analyzing literally hundreds of different Space program scenarios, with any and all mixes of foreseeable Space missions and applications, we concluded by the end of 1971 that an STS employing a Space Shuttle and Space Tug was in the interest of the United States, at a substantially reduced cost from the original plans of NASA (a two stage fully reusable design roughly a 707 on top of a 747 taking off vertically with internal hydrogen tanks etc.) saving the country billions of dollars in the development phase (cutting the RDT&E costs by 50% or more) AND allowing a cost effective, new range of Space operations and uses.
The author presented this result to the NASA Administrator in an October 28, 1971 Memorandum (to assure consideration in the Final Design Selection process set for early November and still limited to two stage designs only). This memorandum was followed in January 1972 by a three volume report and separate Executive Summary, documenting the extensive work done by our group in Princeton with support from Aerospace Corporation (Mission modeling) and Lockheed Missile and Space Corporation (LMSC), the leading contractor for the military uses of Space. Notably, this report explicitly stated that the risk of Shuttle Missions failure was one in fifty.
‘break even’ for the TAOS Shuttle configuration was/is around 25 flights (again including all launches out of East and West coast sites) to all orbits. Two broad ‘families’ of Space programs were analyzed: ballistic missile defense and other DoD programs (the upper range of results depicted in Figure 2.3) and scenarios without such advanced uses. Obviously the case for the Space Shuttle system was better with additional uses in low earth orbits.
Contrary to perceptions held by some, NASA did not ‘assume’ 600 or more space flights to ‘justify’ the Shuttle. This is simply not the case as indicated by all of the testimony throughout the Space Shuttle decision hearings before Congress in the 1970’s. To repeat: however one “massaged” the NASA and DoD mission models (we reduced the mission numbers given to us by the agencies by up to two-thirds) there was no way to “justify” the Space Shuttle based on transportation costs over a 10year, 20 year or even “infinite” time horizon – where “infinity” has a way of shrinking drastically when reasonable discount costs are applied to “future” savings, which was done. Transportation costs were at best a “draw”.
The real reason for reusable STS capabilities – to LEO, GEO and beyond, ideally including Lunar orbits – is in the profound effect these capabilities would (will) have on the very conduct of Space missions, their reliability and capabilities. They would lead to a fundamental change in how to conduct ‘Near-Earth’ Space missions. Thus, the opening up of the Moon as our ‘natural’ Space Station and Operations Base for Cis- and Trans-Lunar activities will transform and change forever on how we operate and use Earth and Near Earth Space.
Today, thirty plus years later, the author would not change a single sentence, conclusion or recommendation made in 1971. The concluding observations to NASA deserve highlighting: The economic basis for the Space Shuttle and Tug were sound and solid – AS LONG AS NASA AND THE NATION HAD AN ACTIVE SPACE PROGRAM ALONG THE SCALED BACK SCENARIOS OUTLINED AND USED BY US.
The initial Space Transportation System Recommendations of 1971 – The 1972 decision to proceed with a new Space Transportation System – including the TAOS Shuttle and the Space Tug – was the last significant, courageous and strategic Space program decision assuring an aggressive U.S. Space strategy for the rest of the century to well into the next millennium: all this at an affordable budget profile substantially less than that expended on the Apollo program of the 1960’s, the vision for which President Kennedy and his generation will be remembered in millennia to come. The salient technical transportation components recommended at that time were :
· TAOS instead of Two Stage Fully Reusable Shuttle. The TAOS Orbiter Shuttle represented a substantial reduction in development costs, risks and schedules over the desire by NASA to develop a two stage fully reusable Orbiter AND Booster – with the estimated development costs reduced by a factor of three to four (from 50 to $60 billion in 1970 dollars to 15 to $20 billion for TAOS, a savings of at least $40 billion
· A reusable Space Tug To assure access to all Earth orbit missions to the new STS and its new philosophy of payload standardization for in orbit repairs, refurbishment, updating and rescue for high mission availability;
· An Ambitious Unmanned Space Missions program, including all “conventional” DoD programs then deployed; two novel DoD missile defense missions, one “kinetic” (then called ‘killer bees’), one laser based (Max Hunter’s concept of 1968); “conventional” science and commercial programs such as communications, observations, navigation and life sciences programs; an entirely new class of science and commercial space capabilities (such as Large Astronomy Observation platforms – e.g. the Hubble Space Telescope and several others which availed themselves uniquely of the new STS capabilities – and large geosyncronous Space communications platforms of entirely new dimensions allowing global point to point communications without ground networks.); and
· Enabling whatever Manned Space Program the U.S. might wish to pursue as a
“side benefit” of these capabilities.
Had NASA and the nation fully pursued these programs in the afterglow of the Apollo program achievements, the dominance of the United States in Space would have been absolute. Some of these programs have immensely contributed to changing the strategic perceptions and relations anyhow, others, indeed most still languish to be implemented. The course charted out then still remains to be taken. Most notably in manned Space flight.
NEVER, EVER WOULD IT HAVE OCCURRED TO US, THAT NASA AND THE NATION WOULD ABDICATE THE PURSUIT AND CONQUEST, INDEED DOMINATION OF SPACE.
Big Gemini will fly a maximum of four missions a year. There's no way of ramping up flight rates above that level – the bottleneck is the Titan III launcher. At least a space station is being build.
Reading the leaked Matematica report however one can't help daydreaming about the lost shuttle. The morale might be, NASA gambled a lot and ultimately lost. It should be remembered that, as of 1971 per lack of budget NASA went as far as killing the space station, betting everything on the shuttle itself.
Per lack of space station, a tin can laboratory would have been flown within the shuttle payload bay. At first glance that looks like a dubious substitute to a space station, but in fact it was a long-thought gamble. With the lab in the payload bay the shuttle tookover a good chunk of space station missions, and that inflated its flight manifest artificially.
It should be remembered that NASA sought to earn money when flying the shuttle; and to achieve that, the shuttle had to fly a lot, as much as once a week. The more missions the lower the cost - that was the motto. More generally it was hoped that low cost of space transportation to orbit would help creating new missions, closing the shuttle economic case. With perfect hindsight is was a risky, but audacious, bet. We will never for sure whether it would have paid or not – at least not until a successfull atempt at a RLV is made in the future.
FLIGHT International. 29 August 1974
By DAVID BAKER
Recently a disgruntled economist with the name of Klaus Heiss leaked an economic study he had done of the now defunct space shuttle. That study has been the subject of intense controversy. Some see it as a glimpse of a forever lost era – how the shuttle would have flown a lot, turning the usual space launch business upside down. Others said it was just outrageous – the the numbers touted were utterly naive and unrealistic. Taking the Mathematica study as a point of departure, David Baker picks up an interesting angle – that of counterfactual history. He tries to imagine where woud we be had the shuttle not been cancelled three years ago.
Now that the space shuttle is well under way the technical barriers are coming down and confidence is backed with an enthusiastic optimism for the golden age of cheap commuter travel between Earth and near-space. Just three years ago the much publicised Space Station, a follow-on to Skylab, began to price itself out of future plans and the container method came in.
By packaging several instruments together and mounting them on a pallet, the Shuttle's own cargo bay will serve as the platform from which scientific tasks may be conducted, so capitalising on the enormous ready-made volume built in to the Orbiter. If men are needed to tend the equipment a cheap, pressurised compartment can be carried alongside. This, in essence, is Spacelab, and flights using this European-built laboratory will be called Sortie Missions.
But the Shuttle is not an end in itself and even with Spacelab in the cargo bay it will realise only a small part of the ambitious programme now envisaged for it. To effectively plan a space programme for the 1980s Nasa has built up a Mission Model, using proposals for the use of satellites or spacecraft as a yardstick from which the payload priorities over the next decade and beyond can be determined.
An earlier plan developed in 1971 foresaw 327 possible payloads in a 12-year period and the present model raises this to 507 as a result of cancellation of the Space Station. This is naturally more cost-effective because of the increased launch rate. Non-Nasa Government agencies, private consortia and possible European payloads add a further 173, while the Department of Defence estimates that it will require 304 payloads to be flown into orbit.
Because the Shuttle will be capable of carrying more than one payload per flight the 986 packages can be condensed into 725 flights in the 12-year period between 1980 and 1991. Of this total Nasa will launch 501, or 69 per cent.
The Mission Model is best analysed by dividing it into Sortie (Spacelab) flights and direct-launch missions, in which a satellite is put into orbit or "retrieved. About 34 per cent of all Shuttle flights will use Spacelab, and less than half of these are expected to use the unmanned pallet alone (i.e. without the habitable pressure module). Only 12 per cent of Spacelab flights are devoted to non-US payloads, while US commercial users account for 3 per cent and Nasa for 85 per cent. Thus 34 per cent of all Shuttle flights support 69 per cent of the payload envisaged. The remaining 31 per cent of Shuttle payloads will be direct-launch satellites encompassing Earth-orbit, deep-space and planetary objectives.
But the Shuttle has limitations on performance and not all the anticipated payloads can be launched by the Orbiter alone, although some flexibility exists for tailoring the Shuttle to specific payloads. Normally the Orbiter will carry 23,8801b of propellant, sufficient to provide a l,000ft/sec velocity change for manoeuvring purposes from the two 6,0001b-thrust engines mounted in the rear fuselage.
These rocket motors will be used to provide the final boost into parking orbit, to circularise the orbit at a desired altitude, to provide the energy needed for all orbital changes, and to de-orbit the craft at the end of the mission. Flights from the Kennedy Space Centre, from due east up to 55° inclination require less than 150ft/sec velocity change to reach a 50 x 100 n.m. orbit, while a launch from Vandenberg AFB, 55° il04° inclination, needs 350ft/sec to reach the same orbit after mainengine cut-off. This allows the big propellant tank to fall back to the atmosphere without the need for a retro-rocket. Polar flights are heavily penalised by the increased velocity demand, and these are reflected in the payload figures.
In basic form the Shuttle will be capable of placing a 65,0001b payload in a circular 28-5° orbit at 210 n.m. altitude. With the same payload it can attain a 450 n.m. apogee from a 100-mile orbit. For a 90° orbit the payload is reduced to 35,0001b, the altitude falls to 200 n.m. and the maximum apogee available is only 390 n.m. These figures represent the best trade-off between altitude and payload, although weight changes have only a marginal impact on the orbit and the absolute altitude attainable is relatively insensitive to off-loading from the cargo bay. This is reflected in the payload figures for the 28-5° orbit; whereas 65,0001b can be carried to a circular 210 mile path, reducing the payload weight to 1,0001b raises the altitude by only 75 miles.
To reach higher orbits the Shuttle can be fitted with up to three supplementary fuel tanks fitted in the cargo bay and fed to the two manoeuvring engines by means of additional plumbing. With all three tanks installed the Orbiter gains an, extra l,500ft/sec manoeuvring capability over the l,000ft/sec available by using the integral tanks. This permits the Orbiter to deliver 25,0001b to a circular, 585-mile orbit at 28-5° inclination, or a 1,040-mile apogee from a 100-mile perigee. But even this is too low for many of the payloads proposed in the current Mission Model, in which 43 per cent of all flights require a supplementary method of propulsion. In fact, 17 per cent of all Nasa and DoD missions involve synchronous orbits and this reflects a dilemma of the entire programme.
For several years the Shuttle was seen as a cheap economic launch vehicle, carrying scientists destined for large orbital laboratories and piloted by a cadre of astronauts, ferrying massive supply containers to the permanent Space Stations. The demise of the Space Station has given predicted launch rates a boost, as noted earlier, by transferring orbital laboratory experiments into the Shuttle itself. However the economics of Shuttle launch operations can no longer be regarded as a challenge to the existing family of expendable rockets. This is due both to relatively high launch costs compared with small rockets such as Scout and Delta, and in the higher percentage of flights needing orbital altitudes in excess of those attainable by the Shuttle. The extra propulsive stages needed for these flights cannot be regarded as payload, but must be chargeable to the Shuttle. To do so would be tantamount to classifying the Saturn V third stage as part of the Saturn's payload. Because of this the launch cost per lb of payload weight increases well beyond the $160 obtained by dividing launch cost by maximum payload. In fact, several flights indicate a financial disadvantage in using the Shuttle.
An example of this reasoning is illustrated by the proposed 1986 Mariner-Uranus mission. Although the weight in the cargo bay exceeds 46,0001b the actual spacecraft weighs a mere 2,1371b. Two launch cost figures can be deduced from this. If the entire contents of the cargo bay are charged as payload the launch cost per pound of payload weight comes to $218. If, however, the Mariner spacecraft alone is deemed to be the payload then the launch cost is $4,560/lb payload.
This is an extreme example but it serves to show the influence of an additional propulsive stage in the Shuttle. The Mission Model referred to earlier indicates how effective the Shuttle can be if used for only those missions where a heavy payload is required. For example, Nasa forecasts 14 Shuttle flights into near-Earth orbit in 1980. The average load on each flight will be 25,0721b and since all of this is payload the launch cost comes out at a competitive $36.1/lb payload weight.
Taking another 12-month period, 1983 for example, Nasa expects to mount 40 flights and the picture here becomes very different. The Mission Model anticipates 27 direct Shuttle flights and 13 missions involving the use of an additional propulsion unit. The average payload weight per flight reduces to 13,9091b and the launch cost increases to $674/lb payload weight. Again, the additional propulsion unit needed reduces the cost advantage over expendable rockets and since a higher fraction of DoD payloads require such a boost the economics become less attractive.
Because the Shuttle can offer many advantages denied to the conventional launch vehicle, such as re-usability, retrieval of redundant or faulty satellites and the return of a propulsive stage incapable of Earth-entry by itself, any evaluation of economics must take into account the entire programme envisaged for the period 1980-1991. Based on the current Mission Model, accommodating 986 payloads on 725 Nasa /DoD flights, the Shuttle programme would cost $49,370 million at 1972 prices. Included in this estimate is the need for 80 expendable rockets of the Scout, Delta and Titan classes during the 1980-1982 build-up period. Seven Shuttle vehicles are required to support this Mission Model and the three-year build-up envisages maximum acquisition rates of follow-on Orbiters, so keeping production costs down.
By comparison, the equivalent traffic rate using conventional rockets would cost $63,470 million. The difference between Shuttle and expendable models' shows a gross benefit of $14,100 million during the 12-year period. However, it should be stressed that the expendable rocket model uses criteria developed for the Shuttle, with payloads optimised around the Orbiter. By designing the payload model for expendable rockets in the first place the Shuttle would be hard put to justify its existence. Clearly the new Mission Model is built around the Shuttle itself and this further enhances the argument that not only is Nasa developing a new launch vehicle but also promoting a re-direction of effort in the entire space programme.
As the annual launch rate is reduced, so the economics become increasingly unfavourable to the Shuttle. It is instructive to compare the projected launch weights in the Mission Model with those of the past 12 years. The highest annual Nasa total was that of 1972 when 33,6451b was launched, but the average over the last 12 years has been only 14,0581b per annum. This excludes manned flights since a true comparison must ignore the abnormally heavy weights associated with these programmes of the past. There is no equivalent in current planning for the Gemini/Apollo/Skylab projects and such figures would serve only to cloud the issue. Seen against this past 12-year record are the predicted launch weights for the future and in three typical years taken from the 1980-1991 Mission Model the comparison sets a different pace. Some 351,0001b is to be launched in 1980, 556,3561b in 1983 and 1,052,5251b in 1990. It is this level of effort which generates the $14,100 million cost benefit mentioned above. (DoD missions are excluded from both sets of figures.)
It remains to be seen if Nasa, in concert with other users such as the European Space Agency and Intelsat, can really generate such a busy payload traffic from a relatively static budget.
As we saw earlier Nasa and the DoD will not be able to fulfil all their needs with the present Shuttle performance, even with additional fuel for the two manoeuvring engines. Because of this the USAF is to adapt an existing rocket stage for use with Shuttle payloads from 1980. The Interim Upper Stage, as it is called, will be an expendable booster and will probably take the form of a modified Agena. By 1984 it will be replaced by the Tug (to be developed by Nasa), a more sophisticated propulsion unit capable of dispatching satellites to synchronous or highaltitude orbits, boosting spacecraft to the planets and bringing back payloads to the Shuttle for return to Earth. The interim vehicle arid the Tug will both be made available to customers needing them.
It is too early yet to discuss the design aspects of either the Interim Upper Stage or the Tug—manufacturers are only just starting to look seriously at the concept—but the performance requirements are already defined and this indicates, in turn, the ultimate potential of the first generation Shuttle.
The specification for the cryogenic Tug requires transfer of a 7,0001b payload to synchronous orbit and the return of the vehicle to a 160 n.m. parking orbit. It is then retrieved by the Shuttle, placed in the cargo bay and returned to Earth. If the Tug is on a satellite retrieval mission the down-load is limited to 4,2501b, or 2,7501b on a combined deploy/retrieval flight.
To accommodate these requirements the Tug would be about 35ft long, 15ft in diameter, with a dry weight of 5,2001b and a maximum propellant weight of 55,7001b. The performance calls for a 15,0001b-thrust engine with a specific impulse of 461sec. However, the Tug will not be available before 1984 and the less powerful Interim Upper Stage will not make available anything near this performance during the first five years of Shuttle operations. Even the Tug will not provide the performance needed to meet the requirements for several of the proposed planetary missions. For instance, the velocity increment of 18,000ft/sec needed to reach the outer planets would demand the use of a kick-stage attached to the payload itself. The Tug would propel the spacecraft to a partial escape trajectory, separate and then return to the Shuttle's 160 n.m. orbit. The payload meanwhile would need an additional 6,000ft/sec from the expendable kick-stage to escape from the Earth's gravitational influence. This compromises the economics even more owing to the loss of the supplementary boost stage, which disappears into space along with its payload.
It- is too early to be dogmatic about projected mission models for the 1980s. The existing model, developed by Nasa and the USAF, assumes a static Nasa budget of $3,300 million at 1972 prices but it is difficult to see how the high launch rate can be sustained. For the Nasa flights alone (501 from 1980 to 1991) the Mission Model calls for an average annual outlay of $390 million in launch costs alone. This assumes each Shuttle flight will cost $9-05 million at 1972 prices, with an extra $1 million for each of the 152 Tug flights.
Nasa has consistently attempted to justify the economics of a Shuttle-based space programme on the $5,500 million development figure. But this covers only two Orbiters, and the Mission Model now proposed requires procurement of five more Shuttles at an estimated $250 million each. In addition to this the payload prediction includes 12 Interim Upper Stages, seven Tugs and 16 kick-stages. Development of the Tug alone could cost $1,000 million, excluding additional models. Finally, planning for the Spacelab element envisages five support modules (i.e. the pressurised, manned laboratories) eight experiment modules (cylindrical containers attached to the rear of the support modules, carrying experiments) and 45 separate experiment pallets. In short, a lot of equipment will be needed to support the 986 payloads proposed and it is difficult to accurately predict the effects on the economics of even a minor slip in development schedules
Assuming that the ambitious programme anticipated for the 1980s is a realistic proposition the $14,100 million cost advantage in using the Shuttle for 12 years is going to be offset by the increasing quantity of equipment necessary to support such a venture. Any delay in introducing the full inventory of Shuttles, Tugs, kick-stages and other vehicles now envisaged would keep expendable launch vehicles in business for years. Commercial users such as Intelsat will undoubtedly press vigorously for the retention of conventional rockets, particularly Scout and Delta, unless means can be found to substantially reduce the nearly 2:1 cost penalty of using the Shuttle.
But if these figures reveal anything at all it is that the Shuttle must be seen as an investment in future space capability, bearing in mind the limitations imposed by the phased introduction of equipment. The Mission Model assumes availability of an interim Tug in 1981, capable of re-rendezvous with the Shuttle but not of retrieving a satellite from high altitude. Now that the USAF has pursued the Interim Upper Stage as an expendable unit Nasa will be unable to retrieve satellites above 350 miles until the Tug appears in 1984. Combined deploy/retrieval flights lower this figure considerably. Also, the 12 Interim Upper Stages demanded by the Mission Model assume them to be recoverable. By throwing each unit away for the first five years of Shuttle operations the economics are further compromised.
Clearly, the launch of 800,0001b payload per annum relies on too many factors converging at the right time. The ambitious Mission Model has too* many parallels with the programme proposed in 1969 which envisaged longduration stations in space, lunar bases, lunar orbit stations and nuclear shuttles, to be wholly relevant today. Nasa has to develop and effectively use the Shuttle to survive another decade of space operations, but an over-optimistic attitude has, in the past, left the agency with a string of cancelled projects. Only a realistic attitude to future requirements can hope to reverse this trend.
In conclusion - the Shuttle was hailed as a major technical step forward when it appeared on the scene five years ago, sponsored by a Nasa anxious to keep the huge Apollo industrial machine in being. The Shuttle will undoubtedly have a major part to play in the American and European space programme being schemed for the 1980s, but is not perhaps the total launch vehicle that Nasa appears to consider it. If you have a 65,000lb manned scientific laboratory to place in low Earth orbit, then the Shuttle is just the job. But if you have a 1,0001b communications satellite bound for stationary orbit (and paid for by the shareholders) a good old-fashioned rocket will do the job at half the cost.
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PRINCETON ECONOMIST KLAUS HEISS ANSWERS DAVID BAKER CRITICISM OF THE PLANNED SHUTTLE FLIGHT RATE.
- INPUTS TO THE 1972 SPACE SHUTTLE ECONOMIC STUDY
Contrary to perceptions, the case for the Space Shuttle – and also for the Space Tug, then an integral conceptual part of a reusable Space Transportation System (STS) to service to all Earth orbits – was NOT based on transportation cost savings. Important presentations by the independent assessment team in 1970-71 started with the realization that the Space Shuttle cannot be justified solely with the narrow argument of transportation cost savings.
Indeed it is this statement – that the Space Shuttle System could NOT be justified on the basis of transportation cost savings – and the logical exposition of the REAL case for the Shuttle that won the author the award to do the independent outside assessment by NASA in 1970 to begin with. Imagine: a $3 million contract, limited explicitly to five pages of substantive exposition AND a full day cross-examination as to the rationale AND to start out the presentation with the statement: “The reusable Space Transportation System (Space Shuttle and Space Tug) can NOT be justified on transportation costs!”
So what WAS the logic for having a Space Shuttle and Space Tug – other than reducing the cost of Space transportation? The very first Table in our 1971 Executive Summary and our Main Report to NASA clearly and simply stated that the life cycle costs would be less for New Expendable (rocket) systems than for a Space Shuttle and Tug – some $11 billion vs. $12 billion, NOT counting the costs for manned Space flight missions!
However one “massaged” the NASA and DoD mission models (we reduced the mission numbers given to us by the agencies by up to 67%) there was no way to “justify” the Space Shuttle based on transportation costs over a 10-year, 20-year or even “infinite” time horizon – where “infinity” has a way of shrinking drastically when reasonable discount costs are applied to “future” savings, which we did.
The various Shuttle configurations considered in the 1971-72 assessment are shown and compared in terms of total non-recurring costs (RDT&E, initial fleet of five orbiters) vs. the cost per flight of the various options. These ranged from a fully reusable version (A “707” sitting atop a “747” taking off vertically with all internal LOX/LH2 tanks), to Thrust Assisted Orbiter Shuttles (TAOS) and a “Reusable Crew Module” launched on expendables.
Also shown in Figure A-2 is the effect of interest rates on technical system choices: were funding, costs and risks no issue, then a case could have been made for a fully reusable Shuttle. However, given those constraints the TAOS set of configurations emerged as the choice.
The ‘Orbital Space Plane’ was rejected out of hand, as with the intended uses (with a reusable Space Tug) for carrying all payloads to low, high and geosyncronous orbit and the ensuing ‘payload effects’ the basic rationale for the new Space Transportation System was foregone. Also noteworthy in this context was the fairy tale of the “assumed” $5 million cost for each Shuttle launch. The range of launch costs was clearly identified in ALL reports and testimony to Congress and in three separate GAO ‘in-depth’ reviews in the 1970’s
For TAOS with Solid Boosters (the configuration ultimately chosen by NASA) these costs ranged anywhere from $15 million to $30 million (in 1970 dollars – or about $60 to $120 millions in today’s dollars) depending on assumed launch rates of up to 24 per year, with a clearly stated launch risk of 2% (98% success rate).
In contrast, TAOS with Liquid (Pressure Fed) Boosters would reduce these costs and risks by about half – and would permit the possibility of intact abort throughout launch.
Furthermore, moving toward a fully reusable STS (using modular designs with standardized spacecraft components) would open up totally new ways of operating and assuring space missions – collectively called ‘payload effects’, e.g.,
· The ability to revisit any and all satellites in Earth orbit would allow for cost effective maintenance, repair and updating of components of these spacecraft. Transportation costs constitute only one third of total STS costs. The rest has to do with spacecraft, instruments, data and their processing – in space and on the ground
– and a modular design with standardized components offers great benefits in further reducing costs of the other two- thirds of total STS costs.
· Standardization of Spacecraft and Space systems at the subsystem level was a revolutionary idea in 1970 (still unimplemented, by the way) that promised up to 67% cuts in support costs for spacecraft. Standardization would facilitate repair and updating a satellite subsystem level – permitting relatively untrained personnel to exchange blue, green, pink and whatever other color boxes. As in 1970, only a few Space missions are “outside” the scope of such standardization.
· Reliable On-orbit service reducing the costs of required high confidence capabilities of key national security satellites, which is very expensive to achieve through redundancy of expensive satellites.
· In-orbit modernization made feasible by such replacement and repair capability. This prospect of updating expensive satellites in Space at the component level, is much to be desired over replacing whole systems or – worse – letting old technology linger in Space providing obsolete services.
In this context, our 1971-72 study examined both manned and unmanned missions. We did not want to rationalize the Space Shuttle simply and solely on the basis of man in Space: that would tilt the analysis much too much in favor of the Space Shuttle.
We observed that Space Tug and Space Shuttle would open up extensive new capabilities, e.g., structures larger than could be carried by any expendable system could be standardized and designed for on-orbit repair, replacements, updates, maintenance, etc8. We identified entirely new classes of Spacecraft for science, commerce or defense – in Low Earth Orbit, intermediate orbits, and up to and beyond Geo-synchronous orbits. Dozens of new Space application missions where designed and outlined for NASA, the DoD and private enterprise – once the Space Shuttle and Tug were fully operational, e.g., for
Space Science: one of our first visits in Princeton was to the astronomy department, chaired at that time by Prof. Spitzer. The result of these meetings was what today is known as the Hubble Space Telescope. I'm strongly convinced that, had the unique capabilities of the Space Shuttle been available, this magnificent instrument could have been built, launched, repaired, maintained and modernized much more easily – on the ground, not in space !We also defined half a dozen other scientific Spacecraft, some in LEO, some in HEO and some in GEO, ranging from radar to infrared to multi-spectral instruments of a size and capability hitherto unknown and unimaginable.
· Commercial Applications: particularly for communications and remote sensing. Some applications would develop with or without the Shuttle, e.g., a vast range of communications and navigation satellites, including GPS, a variety of Global resources sensing satellites, low and high Earth orbit communication satellites at a variety of frequency bands. We also foresaw an entirely new class of satellites with vastly expanded capabilities, e.g., a new generation of communication platforms in geo-synchronous orbit with vastly increased power- requirements, on-board switching, data processing and storage; tens of thousands of spot beams, and satellite-to-satellite optical and laser communications allowing point-to-point communications to any place in the world. Direct access to repair, maintain and modernize these platforms was critical to providing 99.999-plus reliability. We envisioned a Global Resources Information System (GRIS) described in detail in the NRC papers of the Snowmass meetings of 1974. The effect on the distribution of world food supplies through the commodities markets alone accounted for billions of dollars in annual benefits. Environmental, energy, geologic and other resource observations benefited as well, including such arcane applications as archeology. Many of these have become reality today, as they can also be achieved with smaller spacecraft, not requiring the capabilities of the Space Shuttle and Tug system.
· Defense Applications: at least one-third of all applications foreseen for the new STS were defense related. They included some of the applications realized since then in navigation (GPS), in observations, in communications, albeit not to the extent possible if we had truly developed the full Shuttle and Tug capabilities, with vistas for expanded uses of Space very similar to those cited for commercial uses above. Building on the considerations of “Bambi” and a seminal 1968 paper by Max Hunter – a member of our team – showing the technical feasibility (in principle) of a Space based laser defense against ballistic missile attacks, we included BOTH options [kinetic (Killer Bees) and lasers] in our analyses of 1971-1972
While not necessary for a positive Space Shuttle decision, these possible space missions would have significantly added to the benefits of the STS then proposed.
Not included in the cost-benefit analysis was a vision of future energy supplies from Space to Earth, e.g., large Solar Power Satellite Platforms of up to 100 square miles in area, first proposed by Peter Glaser of Arthur D. Little. One such platform alone will be able to supply up to 10 GW of electric power to any point on Earth. Also not included were any manned Space flight missions such as a Space Station, or Lunar missions or missions beyond. While these possibilities were recognized, we chose not to comingle them with unmanned Space missions which alone justified the Shuttle-Tug STS on the basis of a cost comparison. Their inclusion would open new horizons, indeed.
Analyzing literally hundreds of different Space program scenarios, with any and all mixes of foreseeable Space missions and applications, we concluded by the end of 1971 that an STS employing a Space Shuttle and Space Tug was in the interest of the United States, at a substantially reduced cost from the original plans of NASA (a two stage fully reusable design roughly a 707 on top of a 747 taking off vertically with internal hydrogen tanks etc.) saving the country billions of dollars in the development phase (cutting the RDT&E costs by 50% or more) AND allowing a cost effective, new range of Space operations and uses.
The author presented this result to the NASA Administrator in an October 28, 1971 Memorandum (to assure consideration in the Final Design Selection process set for early November and still limited to two stage designs only). This memorandum was followed in January 1972 by a three volume report and separate Executive Summary, documenting the extensive work done by our group in Princeton with support from Aerospace Corporation (Mission modeling) and Lockheed Missile and Space Corporation (LMSC), the leading contractor for the military uses of Space. Notably, this report explicitly stated that the risk of Shuttle Missions failure was one in fifty.
‘break even’ for the TAOS Shuttle configuration was/is around 25 flights (again including all launches out of East and West coast sites) to all orbits. Two broad ‘families’ of Space programs were analyzed: ballistic missile defense and other DoD programs (the upper range of results depicted in Figure 2.3) and scenarios without such advanced uses. Obviously the case for the Space Shuttle system was better with additional uses in low earth orbits.
Contrary to perceptions held by some, NASA did not ‘assume’ 600 or more space flights to ‘justify’ the Shuttle. This is simply not the case as indicated by all of the testimony throughout the Space Shuttle decision hearings before Congress in the 1970’s. To repeat: however one “massaged” the NASA and DoD mission models (we reduced the mission numbers given to us by the agencies by up to two-thirds) there was no way to “justify” the Space Shuttle based on transportation costs over a 10year, 20 year or even “infinite” time horizon – where “infinity” has a way of shrinking drastically when reasonable discount costs are applied to “future” savings, which was done. Transportation costs were at best a “draw”.
The real reason for reusable STS capabilities – to LEO, GEO and beyond, ideally including Lunar orbits – is in the profound effect these capabilities would (will) have on the very conduct of Space missions, their reliability and capabilities. They would lead to a fundamental change in how to conduct ‘Near-Earth’ Space missions. Thus, the opening up of the Moon as our ‘natural’ Space Station and Operations Base for Cis- and Trans-Lunar activities will transform and change forever on how we operate and use Earth and Near Earth Space.
Today, thirty plus years later, the author would not change a single sentence, conclusion or recommendation made in 1971. The concluding observations to NASA deserve highlighting: The economic basis for the Space Shuttle and Tug were sound and solid – AS LONG AS NASA AND THE NATION HAD AN ACTIVE SPACE PROGRAM ALONG THE SCALED BACK SCENARIOS OUTLINED AND USED BY US.
The initial Space Transportation System Recommendations of 1971 – The 1972 decision to proceed with a new Space Transportation System – including the TAOS Shuttle and the Space Tug – was the last significant, courageous and strategic Space program decision assuring an aggressive U.S. Space strategy for the rest of the century to well into the next millennium: all this at an affordable budget profile substantially less than that expended on the Apollo program of the 1960’s, the vision for which President Kennedy and his generation will be remembered in millennia to come. The salient technical transportation components recommended at that time were :
· TAOS instead of Two Stage Fully Reusable Shuttle. The TAOS Orbiter Shuttle represented a substantial reduction in development costs, risks and schedules over the desire by NASA to develop a two stage fully reusable Orbiter AND Booster – with the estimated development costs reduced by a factor of three to four (from 50 to $60 billion in 1970 dollars to 15 to $20 billion for TAOS, a savings of at least $40 billion
· A reusable Space Tug To assure access to all Earth orbit missions to the new STS and its new philosophy of payload standardization for in orbit repairs, refurbishment, updating and rescue for high mission availability;
· An Ambitious Unmanned Space Missions program, including all “conventional” DoD programs then deployed; two novel DoD missile defense missions, one “kinetic” (then called ‘killer bees’), one laser based (Max Hunter’s concept of 1968); “conventional” science and commercial programs such as communications, observations, navigation and life sciences programs; an entirely new class of science and commercial space capabilities (such as Large Astronomy Observation platforms – e.g. the Hubble Space Telescope and several others which availed themselves uniquely of the new STS capabilities – and large geosyncronous Space communications platforms of entirely new dimensions allowing global point to point communications without ground networks.); and
· Enabling whatever Manned Space Program the U.S. might wish to pursue as a
“side benefit” of these capabilities.
Had NASA and the nation fully pursued these programs in the afterglow of the Apollo program achievements, the dominance of the United States in Space would have been absolute. Some of these programs have immensely contributed to changing the strategic perceptions and relations anyhow, others, indeed most still languish to be implemented. The course charted out then still remains to be taken. Most notably in manned Space flight.
NEVER, EVER WOULD IT HAVE OCCURRED TO US, THAT NASA AND THE NATION WOULD ABDICATE THE PURSUIT AND CONQUEST, INDEED DOMINATION OF SPACE.
- Archibald
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