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Earth reentry of capsules, space shuttles and meteors are characterized by the presence of very strong shock waves that generate huge temperatures (over 10 000 K). At these temperatures, powerful endothermic chemical reactions start to take place, thus decreasing the temperature field. Unfortunately, the mechanism of these chemical reactions that alleviate the task of thermal shield of reentry space vehicles is not very well understood. For this reason, the present paper deals with the application of two chemical reaction mechanisms to a Marco Polo reentry capsule.

Affordable space access requires partial or ideally full launch vehicle reuse, which is in line with clean environment requirement. Although the idea is old, the practical use is difficult, requiring very large technology investment for qualification. Rocket gliders like Space Shuttle have been successfullyoperated but the price and correspondingly the energy footprint were found not sustainable. For medium launchers, finally there is a very promising platform as Falcon 9. For very small launchers the situation is more complex, because the performance index (payload to start mass) is already small, versus medium and heavy launchers. For partial reusable micro launchers this index is even smaller. However the challenge has to be taken because it is likely that in a multiyear effort, technology is going to enable the performance recovery to make such a system economically and environmentally feasible. The current paper is devoted to a small unitary glide back booster which is foreseen to be assembled in a number of possible configurations. Although the level of analysis is not deep, the solution is analyzed from the aerodynamic point of view. A wind tunnel model is designed, with an active canard, to enablea more efficient wind tunnel campaign, as a national level premiere.

A guarded-hot-plate apparatus [1] has been developed to measure the thermal conductivity of spray-on foam insulations (SOFI) at temperatures ranging from 30 K to 300 K. The foam tested in the present study is NCFI 24-124, a polyisocyanurate foam used on the External Tanks of the Space Shuttle. The foam was tested first in ambient pressure air, then evacuated and tested once more. These thermal conductivities were compared to the thermal conductivity taken from a sample immediately after being subjected to conditions similar to those experienced by the foam while on the launch pad at Kennedy Space Center. To mimic the conditions experienced on the launch pad, an apparatus was built to enclose one side of the foam sample in a warm, humid environment while the other side of the sample contacts a stainless steel surface held at 77 K. The thermal conductivity data obtained is also compared to data found in the literature.

A terahertz (THz) axial computed tomography system has been developed that uses time domain measurements in order to form cross-sectional image slices and three dimensional volume renderings of terahertz-transparent materials. The system can inspect samples as large as 0.0283 m3 (1 ft3) with no safety concerns as for x-ray computed tomography. In this study, the THz-CT system was evaluated for its ability to detect and characterize 1) an embedded void in Space Shuttle external fuel tank thermal protection system (TPS) foam material and 2) impact damage in a TPS configuration under consideration for use in NASA's multi-purpose Orion crew module (CM). Micro-focus X-ray CT is utilized to characterize the flaws and provide a baseline for which to compare the THz CT results.

The Backscatter X‐Ray (BSX) imaging technique is used for various single sided inspection purposes. Previously developed BSX techniques for spray‐on‐foam insulation (SOFI) have been used for detecting defects in Space Shuttle External Tank foam insulation. The developed BSX hardware and techniques are currently being enhanced to advance Non‐Destructive Evaluation (NDE) methods for future space vehicle applications. Various Thermal Protection System (TPS) materials were inspected using the enhanced BSX imaging techniques, investigating the capability of the method to detect voids and other discontinuities at various locations within each material. Calibration standards were developed for the TPS materials in order to characterize and develop enhanced BSX inspection capabilities. The ability of the BSX technique to detect both manufactured and natural defects was also studied and compared to through‐transmission x‐ray techniques. The energy of the x‐ray, source to object distance, angle of x‐ray, focal spot size and x‐ray detector configurations were parameters playing a significant role in the sensitivity of the BSX technique to image various materials and defects. The image processing of the results also showed significant increase in the sensitivity of the technique. The experimental results showed BSX to be a viable inspection technique for space vehicle TPS systems.

Throughout history the emergence of new technologies has enabled unforeseen breakthrough capabilities that rapidly transformed the world. Some global examples from the twentieth century include AC electric power, nuclear energy, and turbojet engines. At the systems level, success of both Apollo and the Space Shuttle programs depended upon taming hydrogen propulsion and developing high‐temperature atmospheric reentry materials. Human space development now is stymied because of a great need for breakthrough technologies and strategies. It is believed that new capabilities exist within the present states‐of‐the‐art of superconducting technology that can be implemented to transform the future of human space development. This paper is an overview of three other papers presented within this forum, which summarizes the principles and consequences of StarTram, showing how the resulting breakthrough advantages can lead directly to safe space tourism and massive development of the moon, Mars and the outer solar system. StarTram can implement cost‐effective solar power from space, simple utilization of asteroid material to protect humans from ionizing radiation, and effective defense of the Earth from devastating cosmic impacts. Synergistically, StarTram technologies will revolutionize ground transportation on the Earth, leading to enormous reduction in energy consumption and creation of millions of jobs. High energy lasers will also be discussed because of their importance to power beaming applications.

This paper develops a novel approach for predicting future funding for the total NASA budget and for science activities within that budget. Although the budget process is inherently political, it is adequately characterized by analyzing the last thirty‐two years of NASA budgets, organized by the party of the President. Over the last thirty‐two years, Republicans have increased the buying power of the NASA budget while Democrats have decreased it, with significant differences in the rates. The President’s budget projections for NASA, available since 1990, are used to produce a model that may be applied to future budget projections. Before final conclusions are drawn from these results, the most significant NASA budgetary event of this decade is examined: the one billion dollar share of the American Recovery and Reinvestment Act of 2009. The hypothesis is that an unanticipated, significant, one‐year increase to the NASA budget can affect NASA’s funding profile for more than one year. This is tested with the only other similar event in NASA history, the unanticipated budget increase following the loss of Space Shuttle Challenger in 1986. An event study of the changes in NASA’s total budget before and after the loss of Challenger indicates that the one‐year spike in funding increased subsequent NASA growth rates for four years. These results are combined to predict future NASA top‐level and science budgets for FY 2011 and FY 2012.

The Next Generation Advanced Video Guidance Sensor (NGAVGS) is the latest in a line of sensors that have flown four times in the last 10 years. The NGAVGS has been under development for the last two years as a long-range proximity operations and docking sensor for use in an Automated Rendezvous and Docking (AR&D) system. The first autonomous rendezvous and docking in the history of the U.S. Space Program was successfully accomplished by Orbital Express, using the Advanced Video Guidance Sensor (AVGS) as the primary docking sensor. That flight proved that the United States now has a mature and flight proven sensor technology for supporting Crew Exploration Vehicles (CEV) and Commercial Orbital Transport Systems (COTS) Automated Rendezvous and Docking (AR&D). NASA video sensors have worked well in the past: the AVGS used on the Demonstration of Autonomous Rendezvous Technology (DART) mission operated successfully in "spot mode" out to 2 km, and the first generation rendezvous and docking sensor, the Video Guidance Sensor (VGS), was developed and successfully flown on Space Shuttle flights in 1997 and 1998. This paper presents the flight heritage and results of the sensor technology, some hardware trades for the current sensor, and discusses the needs of future vehicles that may rendezvous and dock with the International Space Station (ISS) and other Constellation vehicles. It also discusses approaches for upgrading AVGS to address parts obsolescence, and concepts for minimizing the sensor footprint, weight, and power requirements. In addition, the testing of the various NGAVGS development units will be discussed along with the use of the NGAVGS as a proximity operations and docking sensor.

A space materials exposure experiment was condcuted on the exterior of the Russian Service Module (SM) of the International Space Station (ISS) using the Micro‐Particles Capturer and Space Environment Exposure Device (MPAC&SEED) of the Japan Aerospace Exploration Agency (JAXA). Results reveal artificial environment effects such as sample contamination, attitude change effects on AO fluence, and shading effects of UV on ISS. The sample contamination was coming from ISS components. The particles attributed to micrometeoroids and/or debris captured by MPAC might originate from the ISS solar array. Another MPAC&SEED will be aboard the Exposure Facility of the Japanese Experiment Module, KIBO Exposure Facility (EF) on ISS. The JEM/MPAC&SEED is attached to the Space Environment Data Acquisition Equipment‐Attached Payload (SEDA‐AP) and is exposed to space. Actually, SEDA‐AP is a payload on EF to be launched by Space Shuttle flight 2J/A. In fact, SEDA‐AP has space environment monitors such as a high‐energy particle monitor, atomic oxygen monitor, and plasma monitor to measure in‐situ natural space environment data during JEM/MPAC&SEED exposure. Some exposure samples for JEM/MPAC&SEED are identical to SM/MPAC&SEED samples. Consequently, effects on identical materials at different positions and operation periods of ISS will be evaluated. This report summarizes results from space environment monitoring samples for atomic oxygen analysis on SM/MPAC&SEED, along with experimental plans for JEM/MPAC&SEED.

The Materials Exposure and Degradation Experiment (MEDET) was recently launched to the ISS on Space Shuttle Flight IE, as part of the EuTEF payload on the external payload facility of ESA’s Columbus module. The experiment will operate in‐orbit for at least 1.5 years, and has the overall objectives of evaluating the effects of the complex low Earth orbit space environment on material properties, investigating material degradation due to contamination, characterising the local ISS environment and measuring the local micro‐particle flux. This paper gives a brief overview of the experiment function and the material samples which are being exposed, before presenting some of the early flight data. In this phase of the mission, all of the instruments are operating successfully, and continuously acquiring data. The preliminary results mainly concern the environmental sensors, which are operating at relatively high acquisition rates (e.g. one reading every few seconds). It has been shown that the docking of the Space Shuttle to the ISS has a significant effect on the local pressure environment. The more complex degradation experiments are acquiring at much slower rates (e.g. one reading per day) and several more months of space exposure will be required before sufficient data is generated to reach conclusions about the behaviour of the materials. However, preliminary data is presented.

A case study is presented for using models in eddy current NDE design for crack detection in Shuttle Reaction Control System thruster components. Numerical methods were used to address the complex geometry of the part and perform parametric studies of potential transducer designs. Simulations were found to show agreement with experimental results. Accurate representation of the coherent noise associated with the measurement and part geometry was found to be critical to properly evaluate the best probe designs.

The NICMOS Cooling System consists of a closed-loop turbo-Brayton cryocooler coupled with a cryogenic circulator that provides refrigeration to the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) on the Hubble Space Telescope (HST). The cryocooler heat is rejected to space through a capillary pumped loop connected to radiators mounted on the side of the telescope. The system was deployed and integrated with NICMOS by astronauts during STS–109 (Space Shuttle Columbia) in March 2002. It has operated nearly continuously without performance degradation since that time, maintaining NICMOS detectors at a constant temperature of 77 K. Miniature, high-speed turbomachines are used in the cryocooler and the circulator loop to provide vibration-free, long-life operation. A small centrifugal compressor and miniature turboalternator are key elements of the closed loop cryocooler. A miniature cryogenic centrifugal circulator in a separate pressurized neon loop transports heat from the NICMOS instrument to the cryocooler interface heat exchanger. This paper describes the development of the system, key operational features, ground and orbital tests prior to its deployment, and operational results during its five-year operational history on orbit.

The Vision for Exploration is currently focused on flying the Space Shuttle safely to complete our Space Station obligations, retiring the Shuttle in 2010, then returning humans to the Moon and learning how to proceed to Mars and beyond. The NASA budget still includes funds for science and aeronautics but the primary focus is on human exploration. Fiscal constraints have led to pursuing exploration vehicles that use heritage hardware, particularly existing boosters and engines, with the minimum modifications necessary to satisfy mission requirements. So, pursuit of immature technologies is not currently affordable by NASA. Beamed energy is one example of an immature technology, from a human exploration perspective, that may eventually provide significant benefits for human exploration of space, but likely not in the near future. Looking to the more distant future, this paper will examine some of the criteria that must be achieved by beamed energy propulsion to eventually contribute to human exploration of the solar system. The analysis focuses on some of the implications of increasing the payload fraction of a launch vehicle, with a quick look at trans-lunar injection. As one would expect, there is potential for benefit, and there are concerns. The analysis concludes with an assessment of the Technology Readiness Level (TRL) for some beamed energy propulsion components, indicating that TRL 2 is close to being completed.

There is currently no method for detecting corrosion under Shuttle tiles except for the expensive process of tile removal and replacement; hence NASA is investigating new NDE methods for detecting hidden corrosion. Time domain terahertz radiation has been applied to corrosion detection under tiles in samples ranging from small lab samples to a Shuttle with positive results. Terahertz imaging methods have been able to detect corrosion at thicknesses of 5 mils or greater under 1” thick Shuttle tiles and 7‐12 mils or greater under 2” thick Shuttle tiles.

Recently, terahertz ray (T‐ray) imaging has emerged as one of the most promising new techniques for NDE applications. This technique, however, is still in its early development, and requires further studies. This work explores the use of state‐of‐the‐art computer modeling technologies to study T‐ray radiation in media. A series of point source synthesis models have been developed, using both the classic Fresnel‐Kirchhoff and the refined Rayleigh‐Sommerfeld formulations. The flexibility of these models enables us to investigate T‐ray propagation through interfaces of various geometry and morphology. That in turn allows us to simulate T‐ray interaction with flaws and hence to predict the flaw responses. In this paper, we present preliminary results of simulating T‐ray inspection of space shuttle's spray‐on foam insulation structure. Included are comparisons with experimental data of drilled holes embedded in foam sample.

The NASA Glenn Research Center’s (GRC’s) Plum Brook Station has a complement of unique, highly capable facilities that can test space flight hardware ranging from development testing at the component, subsystem and system levels up to environmental qualification of very large spacecraft and extraterrestrial surface systems. The facilities can simulate the conditions of free space or the surfaces of the Moon or Mars, including atmospheric pressure and content, temperature and day/night cycles. This paper presents information on the facilities at the Plum Brook Station as they apply to the development of space systems that support the Vision for Space Exploration, and cites specific examples of testing to illustrate those capabilities.

Short‐pulsed terahertz imaging techniques have found application in recent years especially in the areas of nondestructive evaluation, homeland security and biomedical imaging. One such application involves the inspection of bonding between spray on foam insulation (SOFI) and the external tank in the NASA space shuttle. This work discusses a suite of image enhancement techniques that was developed to improve the probability of detection of voids and disbands SOFI. Physics based defect detection and profiling methods are detailed along with initial results. In addition a ray‐tracing model was developed to simulate the inspection process. Results comparing the model and experimental images will also be presented.

The NASA Engineering and Safety Center (NESC) is an independent organization, which was charted in the wake of the Space Shuttle Columbia accident to serve as an Agency‐wide technical resource focused on engineering excellence. The objective of the NESC is to improve safety by performing in‐depth independent engineering assessments, testing, and analysis to uncover technical vulnerabilities and to determine appropriate preventative and corrective actions for problems, trends or issues within NASA’s programs, projects and institutions. Critical to the NESC are teams of experts in a number of core disciplines including nondestructive evaluation (NDE). These teams, designated Super Problem Resolution Teams (SPRTs), draw upon the best engineering expertise from across the Agency and include partnerships with other government agencies, national laboratories, universities and industry. The NESC NDE SPRT provides a ready resource of NDE technical expertise to support NESC Independent Technical Assessments and In...

Terahertz ray imaging is one of the most capable techniques to inspect the space shuttle external tank foam insulation. This technique, however, is limited in its current inspection protocol using indirect substrate reflections. An alternate signal processing approach, working directly on the flaw responses, was lately demonstrated to be able to overcome some of these limitations. In this paper, we report recent progresses made by utilizing this alternate signal processing procedure in additional samples to detect flaws that were missed by the current protocol. We also present a new detection approach using the probabilistic neural network in the context of Bayesian classification. Preliminary results showed that the new Bayesian classification approach can achieve even greater improvement over the alternate signal processing approach.

The Space Shuttle Columbia s catastrophic failure is thought to have been caused by a dislodged piece of external tank spray on foam insulation (SOFI) striking the left wing of the orbiter causing significant damage to some of the reinforced carbodcarbon leading edge wing panels. Microwave and millimeter wave nondestructive evaluation methods have shown great potential for inspecting SOFI for the purpose of detecting anomalies such as small air voids that may cause separation of the SOFI from the external tank during a launch. These methods are capable of producing relatively high-resolution images of the interior of SOFI particularly when advanced imaging algorithms are incorporated into the overall system. To this end, synthetic aperture focusing techniques (SAFT) are being developed. This paper presents some of the preliminary results of this investigation using SAFT-based methods and microwave holography at relatively low frequencies illustrating their potential capabilities for operation at millimeter wave frequencies.

The Thermal Protection System (TPS) used on space shuttles protects the metallic structure from the large amounts of heat created during travel through the atmosphere, both on takeoff and reentry. The shuttle experiences high thermo‐acoustic loading and impact damage from micro‐meteorites, which can cause disbonds, delaminations, chips, cracks, and other defects to the TPS system. To enhance durability and damage tolerance, new TPS tiles with an added protective ceramic‐matrix‐composite layer are being developed. This paper explores the use of pulsed thermography as a quick, diverse, non‐destructive technique, to characterize the TPS system. The pulsed thermography images obtained are presented and analyzed.

The various roles of hydrogen in space technology are identified and discussed. The preeminent position of hydrogen as rocket fuel in launch vehicles is explained and illustrated for the NASA Space Shuttle. The history of hydrogen in launching space vehicles is also briefly summarized. The cryogenic aspects of hydrogen for cooling instruments during flight missions are covered for several past and current systems. The technology of Nickel‐Hydrogen batteries is covered. The storage of cryogenic hydrogen to operate fuel cells and to provide potable water is described for the NASA Apollo and Shuttle Missions. Other less well‐known applications of hydrogen and metal hydrides such as gas gap heat switches, fueling hypersonic scramjet flights to Mach 10 speeds, in‐situ resource utilization on lunar or Martian surfaces, and providing ultrapure reference hydrogen to scientific instruments are also described. Finally, some possible future roles for hydrogen in space exploration are identified.

In a response to the Columbia Accident Investigation Board’s recommendations following the loss of the Space Shuttle Columbia in 2003, NASA developed methods to monitor the orbiters while in flight so that on‐orbit repairs could be made before reentry if required. One method that NASA investigated was an acoustic based impact detection system. A large array of ground tests successfully demonstrated the capability to detect and localize impact events on the Shuttle’s wing structure. Subsequently, a first generation impact sensing system was developed and deployed on the Shuttle Discovery, the first Shuttle scheduled for return to flight.

Recently, terahertz ray (T‐ray) imaging emerged as one of the most promising techniques to inspect the space shuttle external tank foam insulation. This paper demonstrates the application of state‐of‐the‐art computer processing and modeling technologies to assist in further refinement of this new technology. The current protocol of T‐ray inspection and its limitations are first reviewed. New strategies of using signal processing and modeling are then proposed to improve on the flaw detection. Preliminary results are presented on a series of multi‐dimensional signal processing operations of T‐ray signals. The use of models and their comparisons with experimental data from foam samples are also included.

The space environment presents unique challenges and opportunities in the assembly, inspection and maintenance of orbital and transit spaceflight systems. While conventional Extra‐Vehicular Activity (EVA) technology, out of necessity, addresses each of the challenges, relatively few of the opportunities have been exploited due to crew safety and reliability considerations. Extra‐Vehicular Robotics (EVR) is one of the least‐explored design spaces but offers many exciting innovations transcending the crane‐like Space Shuttle and International Space Station Remote Manipulator System (RMS) robots used for berthing, coarse positioning and stabilization. Microgravity environments can support new robotic archetypes with locomotion and manipulation capabilities analogous to undersea creatures. Such diversification could enable the next generation of space science platforms and vehicles that are too large and fragile to launch and deploy as self‐contained payloads. Sinuous manipulators for minimally invasive inspection and repair in confined spaces, soft‐stepping climbers with expansive leg reach envelopes and free‐flying nanosatellite cameras can access EVA worksites generally not accessible to humans in spacesuits. These and other novel robotic archetypes are presented along with functionality concepts.

Studies of the acoustic signals originating from impact damage on Space Shuttle components were undertaken. Sprayed on foam insulation and small aluminum spheres were used as impactors. Shuttle reinforced carbon‐carbon panels, panels with Shuttle thermal protection tiles, and Shuttle main landing gear doors with tiles were targets. Ballistic speed and hypervelocity impacts over a wide range of impactor sizes, energies, and angles were tested. Additional tests were conducted to correlate the acoustic response of the test articles to actual Shuttle structures.

The current DOE General Purpose Heat Source (GPHS) was developed specifically for a SiGe Radioisotope Thermoelectric Generator (RTG) which was to be launched on a Space Shuttle. In such a launch, if the final stage of the deployed spacecraft failed to ignite, the spacecraft and RTG would reenter the atmosphere after about three months in a Shuttle parking orbit. The indium alloy clad containing the radioisotope fuel would have then been at about 1300° C for the entire time on orbit. This would lead to some grain growth in the clad material, which would tend to decrease its ductility. Due to these constraints, it was concluded by the heat source community that safety considerations would require that the clads be maintained at a temperature of at least 930° C through impact. The safety testing for the GPHS RTG programs was therefore conducted with these conditions as guides. Within this set of guidelines, the heat source was shown to be able to safely handle all credible launch and reentry accident events ...

The implementation of terahertz (THz) imaging for non‐destructive evaluation shows great promise in 2 and 3 dimensional non‐contact inspection of non‐conductive materials such as plastics, foam, composites, ceramics, paper, wood and glass. THz imaging employs safe low power non‐ionizing electromagnetic pulses, which produce images with lateral resolution

Three‐dimensional Direct Simulation Monte Carlo simulations of Columbia Shuttle Orbiter flight STS‐107 are presented. The aim of this work is to determine the aerodynamic and heating behavior of the Orbiter during aerobraking maneuvers and to provide piecewise integration of key scenario events to assess the plausibility of the candidate failure scenarios. The flight of the Orbiter is examined at two altitudes: 350 kft and 300 kft. The flow field around the Orbiter and the heat transfer to it are calculated for the undamaged configuration. The flow inside the wing for an assumed damage to the leading edge in the form of a 10‐inch hole is studied.

This work quantitatively assesses residual strains and stresses associated with the weld repair process used to repair cracks on NASA’s space shuttle flow liners. The coupons used in this investigation were made of the same INCONEL 718 alloy used for the flow liners. They were subjected to identical welding and certification procedures that were carried out on the space shuttle. Neutron diffraction measurements at Los Alamos National Laboratory determined residual strains at selected locations in a welded coupon at 293 K and 135 K. The weld repair process introduced Mises effective residual stresses of up to 555 MPa. On comparing the measurements at 293 K and 135 K, no significant change to the residual strain profile was noted at the low temperature. This indicated minimal mismatch in the coefficients of thermal expansion between the base metal and the weld.

The International Space Station (ISS) enables the study of supportability issues associated with long-duration human spaceflight. The ISS is a large, complex spacecraft that must be maintained by its crew. In contrast to the Space Shuttle Orbiter vehicle, but similar to spacecraft that will be component elements of future missions beyond low-Earth orbit, ISS does not return to the ground for servicing and provisioning of spares is severely constrained by transportation limits. Although significant technical support is provided by ground personnel, all hands-on maintenance tasks are performed by the crew. It is expected that future missions to distant destinations will be further limited by lack of resupply opportunities and will, eventually, become largely independent of ground support. ISS provides an opportunity to begin learning lessons that will enable future missions to be successful. Data accumulated over the first several years of ISS operations have been analyzed to gain a better understanding of maintenance-related workload. This analysis addresses both preventive and corrective maintenance and includes all U.S segment core systems. Systems and tasks that are major contributors to workload are identified. As further experience accrues, lessons will be learned that will influence future system designs so that they require less maintenance and, when maintenance is required, it can be performed more efficiently. By heeding the lessons of ISS it will be possible to identify system designs that should be more robust and point towards advances in both technology and design that will offer the greatest return on investment.

Broadly speaking, two types of potential commercial activity in space can be defined. First, there are those activities that represent an expansion and improvement on services with broad existing commercial foundations such as telecommunications. The second type of potential commercial activity in space is one that may offer a type of service with few or any existing commercial foundations such as space‐based remote sensing. Space tourism clearly belongs in the first category of potential commercial activity in space. Roles in cooperation with the private sector that might be considered for NASA include 1) acceleration of the “Professional‐in Space” initiative, 2) research and technology developments related to a) a “Tourist Destination Module” for the Space Station, b) an “Extra Passengers Module” for the payload bay of the Space Shuttle, and c) a “Passenger‐rated Expendable Launch Vehicle,” 3) definition of criteria for qualifying candidate space tourists, and 4) initiatives to protect space tourism from unreasonable tort litigation. As baseline information for establishing fees, the cost of a possible tourist flight should be fully and objectively delineated. If it is correct that the marginal cost of each Space Shuttle flight to Earth‐orbit is about $100 million and the effective Shuttle payload is about 50,000 pounds, then the marginal cost would be roughly $2,000 per pound.

Recently, a study was performed by a team from JPL and the DOE to develop a mission architecture for a reusable NEP Interplanetary Transfer Vehicle, a “Space Truck”. This vehicle is designed to be used for delivery of payloads from Earth to a variety of destinations, including Mars and Venus, dependent on mission needs. In addition to delivering payloads to the target bodies, the vehicle is designed to perform autonomous rendezvous and capture of sample return capsules at the destination for return to Earth. In order to maximize the utility of the vehicle, its design is optimized for servicing between missions with the Space Shuttle. Fuel tanks, ion thrusters, and Power Management and Distribution electronics are all on‐orbit replaceable units, located at the payload interface end of the spacecraft to ensure a minimal radiation dose to the Shuttle and crew during maintenance and resupply operations. Operational flexibility is maximized through the use of replaceable fuel tanks and thrusters, allowing tailoring of fuel load to any given destination and payload mass. This paper discusses the preliminary design developed for the NEP Interplanetary Transfer Vehicle, including its configuration and design features, and outlines the concept for mission design, including discussion of unique requirements for launch, deployment and operations with the Space Shuttle, and rendezvous and servicing by the Shuttle in Earth orbit following a return from each target destination.

The Capillary Pumped Loop 3 (CAPL 3) experiment was a multiple evaporator capillary pumped loop experiment that flew in the Space Shuttle payload bay in December 2001 (STS‐108). The main objective of CAPL 3 was to demonstrate in micro‐gravity a multiple evaporator capillary pumped loop system, capable of reliable start‐up, reliable continuous operation, and heat load sharing, with hardware for a deployable radiator. Tests performed on orbit included start‐ups, power cycles, low power tests (100 W total), high power tests (up to 1447 W total), heat load sharing, variable/fixed conductance transition tests, and saturation temperature change tests. The majority of the tests were completed successfully, although the experiment did exhibit an unexpected sensitivity to shuttle maneuvers. This paper describes the experiment, the tests performed during the mission, and the test results.

Corrosion studies began at the Kennedy Space Center (KSC) in 1966 during the Gemini/Apollo Programs with the evaluation of long‐term protective coatings for the corrosion protection of carbon steel. NASA’s KSC Beach Corrosion Test Site, which was established at that time, has been documented by the American Society of Materials (ASM) as one of the most corrosive naturally occurring environments in the world. With the introduction of the Space Shuttle in 1981, the already highly corrosive conditions at the launch pad were rendered even more severe by the acidic exhaust from the solid rocker boosters. In the years that followed, numerous studies have identified materials, coatings, and maintenance procedures for launch hardware and equipment exposed to the highly corrosive environment at the launch pad. The Corrosion Laboratory was established at KSC in 1985 and was outfitted with state‐of‐the‐art electrochemistry equipment to conduct research and materials characterization in many different corrosive environments. This paper will describe the application of electrochemistry in combination with atmospheric exposure to the selection of alloys in a spaceport environment.

A two-stage miniature pulse tube (PT) cryocooler, designed for a Space Shuttle flight demonstration, was built and tested at Lockheed Martin Astronautics (LMA) and at the NIST Boulder Lab. The Miniature PT Flight Cryocooler (MPTFC) was designed to provide 0.15 W of cooling at 80 K with heat rejection at 275 K. It was developed as the smallest cryocooler of its kind for the purpose of demonstrating launch survivability and thermal performance in a zero-g environment. The flight version was fabricated as a Getaway Special (GAS) Payload. Although on-orbit cooling performance was not demonstrated because of failed primary batteries, the first off-state PT thermal conductance measurements in zero-g were conducted successfully using the secondary battery system. The data acquisition system and all flight diagnostic sensors performed nominally to provide 15 hours of zero-g warm-up data. The results of the cold head thermal conductance measurements both in zero-g aboard STS-90 and in the laboratory environment are compared to a thermal model for the two-stage PT, detailed in a separate presentation.

The NASA/Marshall Space Flight Centers (NASA/MSFC) Propulsion Research Center (PRC) is evaluating an antiproton storage system, referred to as the High Performance Antiproton Trap (HiPAT). This interest stems from the sheer energy represented by matter/antimatter annihilation process with has an energy density approximately 10 order of magnitude above that of chemical propellants. In other terms, one gram of antiprotons contains the equivalent energy of approximately 23 space shuttle external tanks or ET's (each ET contains roughly 740,000 kgs of fuel and oxidizer). This incredible source of stored energy, if harnessed, would be an enabling technology for deep space mission where both spacecraft weight and propulsion performance are key to satisfying aggressive mission requirements. The HiPAT hardware consists of a 4 Tesla superconductor system, an ultra high vacuum test section (vacuum approaching 10(exp -12) torr), and a high voltage confinement electrode system (up to 20 kvolts operation). The current laboratory layout is illustrated. The HiPAT designed objectives included storage of up to 1 trillion antiprotons with corresponding lifetimes approaching 18 days. To date, testing has centered on the storage of positive hydrogen ions produced in situ by a stream of high-energy electrons that passes through the trapping region. However, due to space charge issues and electron beam compression as it passes through the HiPAT central field, current ion production is limited to less then 50,000 ions. Ion lifetime was determined by counting particle populations at the end of various storage time intervals. Particle detection was accomplished by destructively expelling the ions against a micro-channel plate located just outside the traps magnetic field. The effect of radio frequency (RF) stabilization on the lifetime of trapped particles was also examined. This technique, referred to as a rotating wall, made use of a segmented electrode located near the center of the trap on which various phases of a particular frequency were applied. Various experiments were performed illustrating the ability of an RF drive to both prolong and reduced the lifetimes of various ion species depending on the selected frequency. HiPAT is now being reconfigured for testing with an ion source that will provide both positive and negative hydrogen ions from an external source. This ion system shall provide higher fill capacity (order of million of ions per shot), stacking of multiple shots, and injection schemes typical of a realistic antiproton delivery system.

The ASCENT Study is evaluating all those markets (both commercial and government missions) that may be served by a future Second Generation Reusable Launch Vehicle. The markets are being analyzed, and twenty-year forecasts are being generated, in order to assist NASA in defining the attributes of the Second Generation RLV that will eventually replace the Space Shuttle. The forecasts will make possible an evaluation of alternative architectures for the Second Generation RLV, and also help assess the extent to which new commercial markets, enabled by the proposed pricing and reliability benefits of the Second Generation RLV, can contribute to the funding of the vehicle. This paper provides a status of the project at the time of the conference, and describes the way in which the markets are being treated and data is being obtained. The sectors range from the relatively well understood telecommunications markets to the newer evolving market opportunities like public space travel.

NASA's strategic planning for technology investment draws on engineering studies of potential future missions. A number of hypothetical mission architectures have been studied. A recent study completed by The NASA/JSC Advanced Design Team addresses one such possible architecture strategy for missions to the moon. This conceptual study presents an overview of each of the spacecraft elements that would enable such missions. These elements include an orbiting lunar outpost at lunar L1 called the Gateway, a lunar transfer vehicle (LTV) which ferries a crew of four from the ISS to the Gateway, a lunar lander which ferries the crew from the Gateway to the lunar surface, and a one-way lunar habitat lander capable of supporting the crew for 30 days. Other supporting elements of this architecture discussed below include the LTV kickstage, a solar-electric propulsion (SEP) stage, and a logistics lander capable of re-supplying the 30-day habitat lander and bringing other payloads totaling 10.3 mt in support of surface mission activities. Launch vehicle infrastructure to low-earth orbit includes the Space Shuttle, which brings up the LTV and crew, and the Delta-IV Heavy expendable launch vehicle which launches the landers, kickstage, and SEP.

The Advanced Shuttle Upper Stage (ASUS) concept addresses safety concerns associated with cryogenic stages by launching empty, and filling on ascent. The ASUS employs a rapid chill and fill concept, where a spray bar is used to completely chill the tank before fill. Thus the vent valve can be closed during the fill process. The first tests of this concept, using a flight size (not flight weight) tank, were conducted at Marshall Space Flight Center (MSFC) during the summer of 2000. The objectives of the testing were to: 1. Demonstrate that a flight size tank could be filled in roughly 5 minutes to accommodate the shuttle ascent window, 2. Demonstrate a no-vent fill of the tank, and 3. Gather data to validate analytical models. A total of fourteen tests were conducted. Models of the test facility fill and vent systems, as well as the tank, were constructed. The objective of achieving tank fill in 5 minutes was met during the test series. However, liquid began to accumulate in the tank before it was chilled. Since the tank was not chilled until the end of each test, vent valve closure during fill was not possible. Even though the chill and fill process did not occur as expected, reasonable model correlation with the test data was achieved.

Many people refuse to address many of the realities of reusable launch vehicle systems, technologies, operations and economics. Basic principles of physics, space flight operations, and business limitations are applied to the creation of a practical vision of future expectations. While reusable launcher concepts have been proposed for several decades, serious review of potential designs began in the mid-1990s, when NASA decided that a Space Shuttle replacement had to be pursued. A great deal of excitement and interest was quickly generated by the prospect of “orders-of-magnitude” reduction in launch costs. The potential for a vastly expanded space program motivated the entire space community. By the late-1990s, and after over one billion dollars were spent on the technology development and privately-funded concepts, it had become clear that there would be no new, near-term operational reusable vehicle. Many factors contributed to a very expensive and disappointing effort to create a new generation of launch vehicles. It began with overly optimistic projections of technology advancements and the belief that a greatly increased demand for satellite launches would be realized early in the 21st century. Contractors contributed to the perception of quickly reachable technology and business goals, thus, accelerating the enthusiasm and helping to create a “gold rush” euphoria. Cost, schedule and performance margins were all highly optimistic. Several entrepreneurs launched start up companies to take advantage of the excitement and the availability of investor capital. Millions were raised from private investors and venture capitalists, based on little more than flashy presentations and animations. Well over $500 million were raised by little-known start up groups to create reusable systems, which might complete for the coming market in launch services. By 1999, it was clear that market projections, made just two years earlier, were not going to be realized. Investors stopped funding the many private projects, and NASA grew weary of the lack of progress in its funded programs. The elements leading to the demise of NASA’s X-33 and other programs are addressed, and lessons for the future offered.