Space

Testimony

 

of

 

Michael D. Griffin

 

Hearing on the NASA Orbital Space Plane Program

 

Subcommitee on Space and Aeronautics

Committee on Science

 

Rayburn House Office Building

Room 2318

8 May 2003

 

 

Abstract

 

Requirements for NASA's proposed Orbital Space Plane (OSP) and its place in the new Integrated Space Technology Plan (ISTP) are discussed.  Consideration and adoption of appropriate top-level goals for the nation's space transportation architecture is advocated.  The role of OSP relative to the Space Shuttle in support of International Space Station (ISS) is treated.  Key OSP design features, especially the issue of a winged vs. semiballistic vehicle design, are discussed.  OSP programmatic assumptions are examined, with attention to cost, schedule, and technology development requirements. 

 

 

 

Mr. Chairman:

 

Thank you for inviting me to appear before this committee to discuss this most important issue, that of the NASA Orbital Space Plane (OSP) program, and its relationship to the new NASA Integrated Space Transportation Plan (ISTP).

 

I will open by noting that, in my opinion, this is not only a most important topic for discussion, it is the single most important subject to be addressed by the nation's leaders in connection with our nation's future in astronautics. 

 

In aeronautics, the air is merely a medium through which one must transit in order to reach a desired destination.  In astronautics, both air and space become navigable media, but space also becomes much more:  It is itself a destination, a region offering access to an enhanced vantage point, hard vacuum, microgravity, advantageous positioning, and new sources of energy and materials. 

 

But to use these assets we must first reach the destination.  The physics of Earth's gravity well are such that once we reach low Earth orbit (LEO) we are, in Arthur C. Clarke's famous turn of phrase, "halfway to anywhere".  This hearing, one of many such discussions on the topic, is prima facie evidence that despite the passage of sixty years since the invention of the first vehicles capable of reaching space, the task of reaching LEO -- reliably, routinely, and cost-effectively -- continues to elude us.  We are still having trouble taking Clarke's first half-step.

 

The task is difficult.  To reach LEO, we must package the energy required for an intercontinental aircraft flight in a container with the volumetric efficiency of an eggshell, yet which is tough enough to withstand high inertial, thermal, and aerodynamic loads.  The stored energy must be expended within a few minutes, and prevented from being expended in a few seconds.  Each launch of an expendable vehicle is its maiden flight, an event performed under only the most carefully controlled and limited conditions in aeronautics, yet which in astronautics must be a maximum-performance event.  A reusable vehicle must survive a return through an atmospheric flight regime so rigorous it cannot be simulated in even the highest performance wind tunnels; such a vehicle can be fully tested only by flying it "for real". 

 

But while the task is difficult, we have allowed ourselves to make it more difficult than it need be.  We have sometimes concentrated so heavily on particular details and "point designs" that we have failed to appreciate that each such design must blend into, and be part of, a broader architecture.  We have sometimes become enamored of specific requirements, to the exclusion of broader goals.  We have at times over-valued the role of government while failing to pay due attention to the skill and expertise residing in our industrial base.  At other times we have done the opposite, leaving too much to the discretion of contractors who, after all, bear no final responsibility for the success or failure of any government enterprise.  In some cases we have stayed too long with proven but inefficient technology.  In other cases we have designated as "operational" those things which were, at best, operating at the very edge of the state of the art, and possibly beyond it.  We accept, without serious objection, a "cost of doing business" in government space endeavors that should shame us all were it to be examined on any sort of rational basis. 

 

We have made most of the mistakes that can be made, mistakes which would have put any commercial enterprise mercifully out of its misery, in favor of a competitor with a better approach.  But because the development of space launch vehicles has been almost exclusively a government enterprise, and because the few and only competitors have been other governments, normal market mechanisms are absent, and we continue to muddle along.  This does not mean that all of our problems would be solved if we merely turned space launch over to industry, and restricted the government's role to supervising the purchase of tonnage per year to orbit.  The contrary fact is true; the government's role in sponsoring appropriate technology and systems development is crucial, if effective launch vehicle technologies and an efficient free market in space transportation are ever to exist.  We simply need to do it better than we have so far demonstrated.

 

In the wake of the Columbia accident, some have argued for restricting, once again, the frequency and purposes of manned spaceflight, or of restricting shuttle launches to orbits compatible with the International Space Station (ISS).  One hears it said that manned spaceflight should be restricted to those occasions when human presence is "needed".  I cringe when I hear or read such views.  Since there was no human spaceflight at all prior to 1961, it is plain to see that we do not "need" to do it.  We do it from a fundamental desire, inherent in our genes and in our culture, to explore our environment and expand our presence within that environment.  We do it, according to John F. Kennedy's ringing quote, "not because it is easy, but because it is hard".  Bearing this in mind, I submit that NASA's role is not to figure out how to do less manned spaceflight; NASA's role is to figure out how to do more of it.   

 

With these thoughts in mind, I offer the following in response to the questions posed by this committee in its formal invitation to appear.

 

·         What key factors should be considered when evaluating human space transportation architectures?  Is the proposed ISTP an overly optimistic or overly conservative approach to meeting NASA's needs?  What areas of the proposed approach pose the greatest risk?  What recommendations do you have to reduce these risks? 

 

The key element of any system architecture is that it be responsive to an overarching framework of goals.  When a system architecture - or a specific vehicle - is designed without reference to such top-level goals, the result is a point design that is unlikely to blend smoothly into any larger picture.  Rather than being designed to meet a higher purpose, the purpose becomes merely that set of tasks the system can accomplish. 

 

The proposed ISTP seems to lack the required global framework, the desired broader view.  Three elements are specified - the Space Shuttle, a new Orbital Space Plane, and a reusable launch vehicle.  This latter element, potentially the most important of the three, is hardly a factor in the present discussion because it is being deferred for some unspecified period.  What, then, are the questions being asked, for which these three architectural elements are the answers?  This discussion is nowhere to be found in the proposed ISTP.   

 

NASA should lead the debate to define and enunciate the nation's goals in space, and following from them, our goals in the development of space transportation - goals which will guide us for at least a generation.  These goals should be embraced within the Administration, and shared and supported by the Congress, for in this matter there is no conceivable partisan interest.  Properly chosen goals will be shared by the majority of informed stakeholders, and will be broad enough to accommodate the flexibility of timing and funding that future Administrations and Congresses will need and want, without sacrificing their essence.

 

While others may certainly have their own ideas as to the appropriate goals for the nation in space transportation, I believe they should include at least the following:

 

-       Robust and economical small, medium, large, and heavy lift capability to LEO, to the 100 metric ton level or greater.

-       Dependable, available crew transport to and from LEO.

-       Crew escape capability from ISS and other space stations yet to be built in other places.

-       Reliable cargo transport to LEO, including the capability for automated rendezvous, proximity operations, and docking with pre-existing assets.

-       The option, but not the requirement, to combine crew and cargo transport as needed for a particular mission.

-       LEO-to-higher-orbit transfer capability.

-       Efficient lunar and interplanetary transfer capability for both unmanned and manned missions.

 

If I may be permitted an imperfect but possibly useful analogy, NASA is the entity in the U.S. government charged with, and best suited to, creating the "interstate highway" to space.  This highway needs to be designed to handle shipments both large and small, on known and reliable schedules, safely and economically.  The highway is needed because the existing patchwork of separately developed roads is inadequate to serve the future we can envision.  Industry can and must share in the design, and must perform the actual construction.  But only NASA can enunciate the goals and architect the system.

 

Against this larger backdrop, the proposed ISTP can only be seen as far too conservative.  It is not so much wrong, as it is incomplete.  If fully realized, it would leave us with little more capability than we have today to go beyond Earth orbit.  It would do nothing soon to reduce the cost of space access.  It would saddle us for the next two decades with continued primary reliance on the Shuttle, which is by any reasoned measure the riskiest element in the system.  Surely we can do better.

 

·         How might the OSP alter NASA's reliance on, and the flight rate of, the Space Shuttle?  Should crew and cargo delivery be addressed by separate systems?  If the OSP and a separate cargo delivery capability for logistics re-supply were developed, would it be necessary to continue to fly the Space Shuttle?  If so, what missions could not be accomplished without the Space Shuttle?  If the Shuttle is required for the duration of the Space Station, is an OSP that performs both crew rescue and crew transportation required?

 

Given the existing Leve1 1 requirements and their interpretation, the OSP is unlikely to alter substantially NASA's reliance on the Space Shuttle. 

 

The OSP program is specified solely in terms of its requirements to "support" the International Space Station (ISS), where "support" is defined as "supplementing" the existing capabilities of Shuttle and Soyuz.  It must support ISS crew rotation on 4-6 month intervals, and system is to be designed to have minimum life-cycle cost.  These constraining assumptions, offered without reference to a set of higher goals such as articulated above, will have profound consequences in the generation to come.  To see where these assumptions can lead, let us consider the following train of thought. 

 

If the purpose of OSP is to "support" ISS operations by "supplementing" the capabilities of the Shuttle, and ignoring Soyuz for the moment, then clearly the Shuttle must be kept flying, in accordance with the proposed ISTP.  Estimates vary, but it is accepted that a viable Shuttle program requires a minimum of several - let us say three or four - launches per year.  Thus, in the normal course of events, Shuttle alone can easily accommodate ISS requirements.  OSP would then fly only a couple of times per year - if that - to maintain operational currency, or to rotate the vehicle(s) docked at ISS for purposes of emergency crew return.  Under these assumptions, OSP is thus needed only when - as at present - the Shuttle is grounded.  The OSP system thus needs to be designed to accommodate a peak rate of possibly four flights per year for short periods, and much less on average. 

 

With such assumptions, it will be almost guaranteed that the lowest-life-cycle-cost design is a simple (probably expendable) vehicle with the least capability consistent with completing the tasks envisioned today.  A basic semiballistic capsule designed for a few days of independent flight could easily suffice.  By choosing this path - and it is inevitable if we accept the Level 1 OSP requirements as written - we accept the requirement to maintain the inherently high cost Shuttle program.  Worse, we have as our only Earth-to-LEO transportation systems two designs (Shuttle and OSP) which are wholly incapable of being adapted to the needs of lunar return or Mars exploration, ventures which should certainly be of interest over the intended design life of the OSP.  Considered in such a broader context, radically different design choices might be made for OSP.  But they are not possible given the requirements as written.

 

It scarcely needs to be said that it will be extremely hard to justify the development of such a vehicle, at a cost of several billion dollars, for such a limited purpose as OSP will have, given the requirements envisioned for it today.  And, indeed, such development makes little sense economically.  One could likely obtain several replacement Shuttle orbiters in a "block buy" for the same cost as a new OSP.  Further thought in this direction would likely show that the most economical crew return vehicle for ISS would be the Shuttle itself - modified for a 60-to-90 day stay - with four to six crew rotation missions per year.  Following this logic, it becomes difficult to see the path by which reliance on the Shuttle can be ended. 

 

To me, the likeliest result of accepting the OSP Level 1 requirements as written is that a sober analysis will show the OSP to be wholly unjustifiable in economic terms, and the program will subsequently be cancelled in favor of continued use of the Shuttle.  Since the Shuttle is not capable of supporting the larger goals that I have enunciated above, or any similarly broad set of goals, I would consider this outcome to be another setback for NASA and the nation.

 

With regard to separation of crew and cargo, the issue is not "should" they be separated, but "can" they be separated when it is advantageous to do so, as is so often the case.  With the Shuttle, they cannot.  While the Shuttle's large cargo bay is its most impressive feature, it is also the feature which, in my opinion, results in the greatest increment of risk to the astronauts who fly it.  With the cargo bay attached to the crew cabin, the Shuttle orbiter is inherently so large that only a sidemount configuration is possible, leaving the crew with no escape path in the event of a launch malfunction, as with the Challenger failure, and vulnerable to falling debris, possibly including ice, as with the Columbia accident. 

 

If the Shuttle system had been designed with a smaller manned vehicle atop an expendable cargo pod, the overall system would have been much safer.  A simple escape rocket would have sufficed to separate the crew vehicle from the launch system in the event of a malfunction, which is of course ultimately inevitable, given a sufficient number of flights.  The crew vehicle could have been launched, by itself, on a smaller vehicle or vehicles when no cargo was required.  The only lost capability would have been the ability to handle "down cargo", the least-used feature of the Shuttle system.  My own view on the value of "down cargo" is somewhat simplistic:  It is so difficult and expensive to get payloads to space that, having done it, we ought by and large to leave them there, and design them for that!  But, if necessary, I believe that the design of a reusable cargo pod capable of executing an autonomous reentry and landing would pose little challenge.   

 

·         Given that the OSP program has not yet progressed beyond establishing the Level I requirements, do you think NASA's plan for spending approximately $750 million on technology demonstrations between FY03 and FY06 is justified?  What technologies are the most critical to demonstrate before proceeding to full-scale development?

 

Numerous advances in thermal protection materials technology have been made since the Shuttle was designed and built, and some relatively inexpensive demonstrations may be useful in this area.  Automated rendezvous and docking, a procedure so basically straightforward that the Russians first demonstrated it more than three decades ago, remains to be demonstrated in the U.S. program.  Crew escape system technology has been essentially absent from U.S. vehicles since Apollo, and may need some investment.  Isolated technology demonstrations may be required to address issues relevant to a particular vehicle design, once such a design is selected.  However, these are details. I am unaware of any crucial, but as yet unproven, technology needed for Earth-to-LEO transportation.  I believe money spent on technology demonstrations would, in general, be better spent on vehicle development.  Such an approach would also offer the benefit of significantly shortening the planned OSP development schedule.     

 

·         What design alternatives should NASA examine as it performs its concept studies for the OSP?   What changes to the OSP program would you recommend to reduce the cost or accelerate the schedule?  How does the decision to proceed with a design that is totally reusable, partially reusable, or expendable drive design complexity, development schedule, cost, and safety?  Can the OSP schedule be accelerated significantly without introducing unwarranted risks?  If so, what recommendations do you have? 

 

We should be careful to avoid overburdening OSP with ISS crew return vehicle (CRV) requirements.  My view, harkening back to my involvement in the 1993 Space Station redesign effort, and before, has always been that the CRV is properly viewed as a "lifeboat", to be used in an emergency, and likely not otherwise.  As an order of magnitude estimate, we might expect to use it once per decade.  If it is used regularly or routinely, we are doing something seriously wrong with regard to the operation of ISS, something which needs to be remedied.  But stretching the notion of what constitutes a CRV is not the answer.  Therefore, again in my view, crew transport requirements should determine the OSP design, with CRV requirements at the margin. 

 

As an aside, I have personally never been able to understand why a refurbished Apollo spacecraft cannot be outfitted as a perfectly acceptable CRV.  The need for developing a new vehicle to meet the crew escape requirement has never been obvious to me. 

 

Much in the news recently, and for good reason, is the question as to whether the "Orbital Space Plane" should be a "plane" at all.  In the wake of the Columbia disaster, some have called for a return to a "capsule" design, more properly termed a "semiballistic entry vehicle".    Certainly there is strong merit in such a recommendation.  A semiballistic vehicle offers a number of advantages for Earth-to-LEO transport.  It is likely to be more volumetrically efficient and to have less mass than a winged vehicle for the same overall mission requirements, and is much better adapted to any requirements to go beyond low Earth orbit.  Either design can be equally reusable, with the possible exception of the heat shield for the semiballistic vehicle, which will almost surely encounter a higher heat load than for a gliding entry vehicle.  However, and in strong contrast to a winged vehicle, the semiballistic can be designed such that the heat shield is both very simple, completely separable, and easily detachable from the core vehicle, resulting in a system with only one non-reusable component that is not particularly weight critical and can be, almost literally, dirt cheap. 

 

It is often stated that the landing accuracy of a semiballistic vehicle will be inferior to that of a winged design.  This is nonsensical.  If a parachute or parasail is used, today's steerable designs, with pinpoint GPS guidance, allow either design to achieve highly accurate landing point control.  Furthermore, historical data indicates that even without benefit of steerable parachutes and GPS, entirely acceptable landing accuracy can be obtained.  The table below cites the mission-by-mission Apollo landing accuracy (from "Apollo Program Summary Report", NASA TM-X-68725, National Aeronautics and Space Administration, Johnson Space Center, Houston, TX, April 1975).  It is seen that the worst-case landing dispersion would have been trivially contained within the boundaries of Edwards AFB, or White Sands Missile Range, or even within acceptable landing areas at Cape Canaveral or Wallops Flight Facility.  Most of the Apollo landing dispersions would have fitted easily within the boundaries of Dulles Airport.  It is not necessary to do better than that.

 

¹Best estimate based upon recovery ship positioning accuracy, command module computer data, and trajectory reconstruction.

 

Note the phrase above, "if a parachute is used".  It is not obvious that a parachute is necessary (other than possibly as a backup system, wherein the goal becomes crew, rather than vehicle, survival).  The terminal velocity of a semiballistic vehicle will be on the order of 300 miles per hour, probably less.  Braking rockets ignited at high altitude, initially at idle thrust, and then smoothly throttled to touchdown can serve quite well, as the DC-X and DC-X-A programs have shown.  Besides demonstrating the ultimate in pinpoint landings in the nominal case, these efforts also showed how a backup parachute landing system can be efficiently incorporated into the design, and used effectively in an emergency.  Detailed studies have continued to reveal no substantive mass difference between a semiballistic design with terminal rocket braking, and a more traditional winged design. 

 

Of course, there is also the possibility of using conventional parachute descent, with surface contact cushioned by short-duration, high-thrust rockets as in the Soyuz design.  Thus, there is no need to assume the inconvenience of an Apollo-style water landing if a semiballistic design is chosen, except possibly in a dire emergency when, in contrast to a winged vehicle, the ability of a semiballistic to survive a ditching then becomes an attractive option.

 

However, because we should carefully consider the merits of a semiballistic crew vehicle design does not mean that we should ignore the merits of a winged design.  Various lifting body research programs, as well 198 successful X-15 flights and 116 successful Shuttle landings (including approach and landing tests with the Enterprise vehicle) have demonstrated the efficacy with which unpowered descent and landing can be performed.  Highly efficient blended delta-wing, lifting body shapes, such as the NASA Langley HL-20 and its derivatives, have been thoroughly characterized.  So there is a wide range of attractive options available.

 

When considering winged vehicle designs, however, I think we have ignored one of the best options, the straight-winged design, for somewhat specious reasons.  All else being equal, it is well understood that a straight-wing design will have less mass, lower heat loads, a higher subsonic lift/drag ratio, a lower landing speed, a shallower glide path on approach, and better subsonic handling characteristics than a comparable delta-wing design.  The delta-wing design offers as its principal advantage a somewhat greater entry crossrange capability than for a comparable straight-wing design.  This allows greater maneuverability from orbit to reach a given landing site, as opposed to waiting on-orbit for perhaps half a day for another opportunity to reach the site.  The delta-wing design also allows the so-called "abort once around", meaning that the Shuttle can land at its launch site after only one orbit, in the event of a severe anomaly.  This greater atmospheric maneuverability was the reason for its selection for the Space Shuttle design, and was a source of considerable controversy at the time.  But in over a hundred Shuttle flights, operational practice has shown that this enhanced crossrange capability is at most a minor convenience, rather than a significant enabling feature.  Any consideration of a new, winged, spaceplane should take these facts into account in determining a design configuration.

 

When contemplating designs for a new winged space plane, it may not be beyond the bounds of reason to examine the swing-wing concept, so successful on the F-14 fighter aircraft.  Providing robust, mass-efficient thermal protection of the wing leading edges is among the most difficult, and unforgiving, tasks in a spaceplane design.  With a swing-wing concept, it might be possible to avoid this task altogether.  For such a vehicle, the atmospheric entry phase would be performed as a semiballistic design, while terminal area energy management, approach, and landing would be performed as a conventional winged vehicle.  As always, there are tradeoff analyses to be conducted, but the concept may be worth pursuing. 

 

The issue of OSP reusability is complex, which of course is why it attracts so much debate.  The primary reason to prefer a reusable vehicle is that, in all reason, it should be cheaper to operate.  Secondary reasons may include the fact that ground and flight crews gain experience with the nuances of a particular machine, a valuable benefit when compared to the obvious risks of undertaking a maiden voyage for every flight of an expendable vehicle.  However, for the moment let us restrict the discussion to economic issues.

 

The economic benefits of reusability are strongly conditioned by the cost of incorporating the necessary features into the design and fabrication of the vehicle, and by its assumed flight rate and operational lifetime.  As a simple example, if it will cost five times more to build a reusable vehicle than to build a comparable expendable design, the reusable vehicle must fly five times to break even with the expendable, assuming their processing costs are similar.  Moreover, most of the cost for the reusable vehicle is incurred "up front", while a greater proportion of the expendable vehicle cost is incurred only when the next unit is actually procured.  Time-value-of-money considerations can thus strongly benefit the expendable vehicle when flight rates are low, and when decisions are made on a lowest-life-cycle-cost basis.

 

The issue of designing to minimize life-cycle cost is worth some discussion.  It should be noted that, over more than two decades of Shuttle operation, the program has encountered much criticism because year-to-year operational costs have been quite high when considered on a per-flight basis.  This has been directly traced, in part, to early-1970s budget constraints on initial design and development, when numerous choices were made which had the effect of minimizing (or appearing to minimize) development cost, while increasing operational costs.  Again because of time-value-of-money considerations, the strategy of designing the vehicle to minimize development cost is closely akin to that of a design based on minimizing life-cycle cost, especially when the vehicle will be in service for a long time.  While neither principle is inherently wrong, each should be applied in moderation.  Life cycle costs are heavily biased by early-year, or "up front", costs.  It is always easy to defer operational funding problems to the "out years".  Yet, when the "out years" arrive, as they always do, we seem consistently to regret the pattern of earlier choices, which were of course intended to "save" money.  Is it possible, this time, that we could at least make a new mistake?      

 

As outlined earlier, it will be tempting on economic grounds to consider an expendable design for OSP, for the reasons just mentioned.  I believe this is a mistake; if done, it will represent a failure of government to lead where industry, by itself, cannot go.  An argument to go backward, toward deliberate use of expendable vehicles for manned spaceflight, is an argument which inevitably favors the doing of less manned spaceflight, precisely because out-year operational costs will always been seen as unacceptably high when the out-years arrive.  This should not be our goal.

 

With respect to cost, I would like to offer a cursory figure of merit, a target cost-per-pound of delivered hardware.  It is well established within the aerospace community that such figures of merit offer a valid first-order estimate of likely program cost; indeed, such parameters form the basis of all accepted cost models.  Therefore, I would advocate that the OSP design, development, test, and evaluation (DDT&E) costs should be upper bounded at $100,000 per pound for the dry mass of the vehicle.  The nation's experience base with reusable manned space vehicles is limited, but both X-15 and the Space Shuttle orbiter would seem to fit this definition.  In recent-year dollars, both were completed at a DDT&E cost of approximately $90,000 per pound of delivered hardware.  If the OSP is allowed to cost more, we are conveying the message that nothing at all has been learned in 40+ years of manned spaceflight.

 

Regarding the program schedule, it seems inconceivable to me that a nation which required only eight years to reach the moon, from virtually a standing start, can require a similar or greater length of time to design and deploy a simple crew transport vehicle.  If the OSP program requires more than five years - at the outside - from authorization to proceed until first flight, it is being done wrong.  My primary recommendation, the only one I think can affect the outcome in a significant manner, is this:  Define carefully the goals the OSP is to meet.  Pick a strong, effective, proven, and trusted program manager, and accord to him or her the total authority and responsibility for success.  Set aside the necessary funds, with adequate margin.  And then see to it that everyone else stays out of the way.

 

·         What challenges may NASA face in using an Expendable Launch Vehicle (ELV) as the boost vehicle for the OSP?  Does the use of an ELV for human spaceflight pose an unacceptable risk?  

 

In the 1950s and 1960s, the term "man rating" was coined to describe the process of converting the military Redstone, Atlas, and Titan II vehicles to the requirements of manned spaceflight.  This involved a number of factors such as pogo suppression, structural stiffening, and other details not particularly germane to today's expendable vehicles.  The concept of "man rating" in this sense is, I believe, no longer very relevant. 

 

If a winged design is chosen for OSP, there will be an issue of coupling between the OSP vehicle aerodynamics and the launch vehicle structural dynamics.  Briefly, the OSP must be oriented and flown very close to its zero-lift aerodynamic angle of attack.  Any significant amount of lift on the OSP wings will create lateral loads at the OSP/launch vehicle interface that are quite likely unacceptable, at least without additional structural reinforcement at that interface.  However, it must be said that launch vehicle loads are likely not the limiting factor; the wings of a spaceplane cannot themselves accept high lateral loads without being ripped off.  The problem is a familiar one; the Shuttle must be flown with a nearly zero angle of attack for similar reasons.

 

Therefore, irrespective of the launch system used for a winged OSP, the vehicle must be flown at essentially a zero-lift angle of attack, and any variations due to vehicle aeroelasticity must be carefully controlled.  While the problem is certainly not trivial, it is not likely to be any more difficult for the new evolved expendable launch vehicle (EELV) than it will be for a winged OSP attached to a future RLV. 

 

The base reliability of unmanned expendable vehicles seems to arouse concerns where that of the manned Shuttle system inexplicably does not. Many, if not most, unmanned payloads are of very high value, both for the importance of their mission, as well as in simple economic terms.  The relevant question may be posed quite simplistically:  What, precisely, are the precautions that we would take to safeguard a human crew that we would deliberately omit when launching, say, a billion-dollar Mars Exploration Rover (MER) mission?  The answer is, of course, "none".  While we appropriately value human life very highly, the investment we make in most unmanned missions is quite sufficient to capture our full attention.

 

Logically, therefore, launch system reliability is treated by all parties as a priority of the highest order, irrespective of the nature of the payload, manned or unmanned.  While there is no EELV flight experience as yet, these modern versions of the Atlas and Delta should be as inherently reliable as their predecessors.  Their specified design reliability is 98%, a value typical of that demonstrated by the best expendable vehicles.  If this is achieved, and I believe that it will be, and given a separate escape system with an assumed reliability of even 90%, the fatal accident rate would be 1 in 500 launches, substantially better than for the Shuttle.  Thus, I believe that launching OSP on an expendable vehicle would pose no greater risk - and quite likely somewhat less risk - for human spaceflight than is already accepted for the Shuttle.

 

Witness Biography

 

 

Michael D. Griffin is President and Chief Operating Officer of In-Q-Tel, the independent, nonprofit venture group chartered to identify and invest in cutting-edge commercial technologies for intelligence community applications.  

 

Mike was previously CEO of the Magellan Systems Division of Orbital Sciences Corporation, and also served as General Manager of Orbital's Space Systems Group and as the company's Executive Vice President/Chief Technical Officer.  Prior to joining Orbital, he was Senior Vice President for Program Development at Space Industries International, and General Manager of the Space Industries Division in Houston. 

 

Mike has served as both the Chief Engineer and the Associate Administrator for Exploration at NASA, and as the Deputy for Technology of the Strategic Defense Initiative Organization.  Before joining SDIO, he played a leading role in numerous space missions while employed at the Johns Hopkins Applied Physics Laboratory, the Jet Propulsion Laboratory, and Computer Sciences Corporation. 

 

Mike holds seven degrees in the fields of Physics, Electrical Engineering, Aerospace Engineering, Civil Engineering, and Business Administration, and has been an Adjunct Professor at the George Washington University, the Johns Hopkins University, and the University of Maryland.  He is the lead author of over two dozen technical papers and the textbook Space Vehicle Design.  He is a recipient of the NASA Exceptional Achievement Medal, the AIAA Space Systems Medal, and the DoD Distinguished Public Service Medal, and is a Fellow of the AIAA and the AAS.  He is also a Registered Professional Engineer in Maryland and California, and a Certified Flight Instructor with instrument and multiengine ratings.