Browse Topic: Expendable launch vehicles

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Vented Launch Vehicle Adapter for a Manned Spacecraft With “Pusher” Launch Abort SystemTBMG-2768610/1/2017
A Launch Vehicle Adapter (LVA) was developed that provides a structural interface between a Commercial Crew Vehicle (CCV) Crew Module/Service Module Spacecraft (CM/SM) and an expendable launch vehicle. It also provides a means to control the exhaust plume from a pusher type launch abort system integrated into the Service Module.
Range Safety Flight Elevation Limit Calculation SoftwareTBMG-189051/1/2014
This program was developed to fill a need within the Wallops Flight Facility workflow for automation of the development of vertical plan limit lines used by flight safety officers during the conduct of expendable launch vehicle missions.
Thrusters Support GOES-R Satellite SeriesTBMG-1755810/1/2013
Aerojet Rocketdyne, a GenCorp company, has shipped the first set of four solar electric propulsion thrusters to Lockheed Martin at NASA’s Stennis Space Center in Mississippi. Lockheed Martin will integrate the Aerojet Rocketdyne SEP thrusters and associated power conditioning units and electrical cabling with the Geostationary Operational Environmental Satellite-R Series (GOES-R) spacecraft.
Filling the Space13AERD0603_016/3/2013
A look at the changing face of manned spaceflight and the commercialization of orbital access. Persuading politicians to fund big-scale space projects is more difficult today than ever, as witnessed by the scores of advanced spaceplane and expendable launcher projects that have fallen by the wayside over the last 30 years. But access to space is still vital as satellites keep the global economy moving and enable seamless real-time financial trading and communication at a level of reliability and accuracy that was unthinkable three decades ago, and plenty of nations still want to do it. Apart from the established major space players in the U.S., Europe, and Russia, China, Japan, and India also have ambitious national space programs.
Gardner, Richard
Low-Cost Phased Array Antenna for Sounding Rockets, Missiles, and Expendable Launch VehiclesTBMG-1509911/1/2012
A low-cost beamformer phased array antenna has been developed for expendable launch vehicles, rockets, and missiles. It utilizes a conformal array antenna of ring or individual radiators (design varies depending on application) that is designed to be fed by the recently developed hybrid electrical/ mechanical (vendor-supplied) phased array beamformer. The combination of these new array antennas and the hybrid beamformer results in a conformal phased array antenna that has significantly higher gain than traditional “omni” antennas, and costs an order of magnitude or more less than traditional phased array designs.
Applications of Probabilistic MethodsAIR5109 (Current)5/8/2012
This SAE Aerospace Information Report (AIR) addresses the following: 1 Captures previous experience and lessons learned in the application of PM. 2 Tabulates public-domain applications, and several representative examples discussed in detail. 3 Notes relative merits and barriers to implementation. The document does not contain technical details of probabilistic methods, benchmarking of specific approaches or legal aspects. These subjects are covered in other AIRs, referenced in Section 2 and prepared by the Probabilistic Methods Committee of the G-11 Reliability, Maintainability, Supportability and Logistics (RMSL) Division of SAE.
G-11 Probabilistic Methods Committee
The Semantic Web and Space Operations2011-01-250610/18/2011
In this paper, we introduce the use of ontologies to implement the information developed and organized by resource planning tools into standard project management documents covering integrated cost, resource modeling and analysis, and visualization. The basic upper ontology used for NASA Space Operations is explained and the results obtained are discussed. This ontology-centered approach is looking for tighter connections between software, hardware, and systems engineering.
Rabelo, Luis, Marin, Mario, Fishwick PhD, Paul, Ezzell, Zach
The Art and Science of Systems Engineering Tightly Coupled Programs2010-01-232110/19/2010
This paper discusses the fundamentals of architecting a major human spaceflight program and some of the lessons that can be learned from NASA's Constellation Program. This paper describes the Constellation program, whose primary objective focuses on development of a new generation of vehicles and systems to enable human exploration beyond Earth orbit. Constellation is made up of seven projects that are highly interdependent and is referred to in the NASA management system as a “tightly coupled” program. This paper will discuss the driving architectural priorities and characteristics for human exploration missions beyond earth orbit and how its building blocks are developed through initial capability missions to the International Space Station. The systems engineering challenges of simultaneously defining and developing systems that are interdependent will be discussed.
Muirhead, Brian K., Thomas, Dale
Loosely Coupled GPS-Aided Inertial Navigation System for Range SafetyTBMG-78234/1/2010
The Autonomous Flight Safety System (AFSS) aims to replace the human element of range safety operations, as well as reduce reliance on expensive, downrange assets for launches of expendable launch vehicles (ELVs). The system consists of multiple navigation sensors and flight computers that provide a highly reliable platform. It is designed to ensure that single-event failures in a flight computer or sensor will not bring down the whole system. The flight computer uses a rules-based structure derived from range safety requirements to make decisions whether or not to destroy the rocket.
Ku Telemetry Modulator for SuborbitalTBMG-635812/1/2009
A modulator utilizing the Ku-band instead of the usual S-band has been developed to improve transmission rates for suborbital platforms. The unit operates in the 14.5–15.5-GHz band and supports data rates up to 200 Mbps. In order to keep the modulator costs low, the modulator is based on the LCT2 [Low Cost TDRSS (Tracking and Data Relay Satellite System)] Transceiver design, which utilizes a single-board modulator incorporating an Analog Devices quadrature modulator IC, with I&Q [inphase (I) and quadrature (Q)] bandwidths of 70 MHz. A pin-compatible version of the chips with I&Q bandwidths of up to 160 MHz is used to achieve the higher data rates. To support the higher data rate, an LVDS (low-voltage differential signaling) user interface will be incorporated into the modulator board. The LCT2 configuration uses a 1×4 in. (≈2.5×10.2 cm) high-power S-band amplifier module. The new amplifier printed circuit board (PCB) module is replaced with a compact S-band to Ku-band upconverter, with an RF output of +5 dBm.
Investigation of Life Support and Habitability Requirements for a Pressurized Lunar Rover2009-01-25057/12/2009
The Terrapin Undergraduate Rover for Terrestrial Lunar Exploration (TURTLE) system was developed as part of a senior design course at the University of Maryland; it has since become a test bed for habitability and life support studies. The design requirements for the project dictated a 2,500 kg pressurized lunar rover to sustain two crew members for eight days with a range of 100 km. Part of the design effort included a full-scale mock-up populated with volumetric representations of interior elements. This research proposes a solution to the life support requirements for spacecraft as well as design requirements for other habitat elements. An analysis of relevant technologies and their application to small rovers is presented. Habitability issues (with respect to interior layout of life support hardware) are also considered. Testing was done with the full-scale TURTLE mockup to determine suitable configuration of life support equipment. In addition, the logistical demands of a rover-outpost combination are discussed and design requirements for both are included.
Husain, Syed-Ali A., Akin, David L.
The Future of Space PropulsionTBMG-489410/1/2008
Significant challenges and advances in space propulsion have occurred over the past ten years. The end of the Cold War had significant impacts, both positive and negative. Operational systems now have to operate well beyond their design life. Parts and technology obsolescence are having a significant impact, as are an aging workforce and limited opportunities to develop new systems. The advent of asymmetric warfare is fully upon us. The military has to pro - ject power anywhere on the globe. In addition, there is concern that U.S. space assets are vulnerable in this new world. Furthermore, changes in acquisition policy driven by incredible cost and schedule overruns on nearly every space acquisition program will have significant impacts on the future of propulsion.
Generic Environment for Simulating Launch OperationsTBMG-17162/1/2006
GEM-FLO (A Generic Simulation Environment for Modeling Future Launch Operations) is a computer program that facilitates creation of discreteevent simulation models of ground processes in which reusable or expendable launch vehicles (RLVs) are prepared for flight. GEM-FLO includes a component, developed in Visual Basic, that generates a graphical user interface (GUI) and a component, developed in the Arena simulation language, that creates a generic discrete-event simulation model. Through the GUI, GEM-FLO elicits RLV design information from the user. The design information can include information on flight hardware elements, resources, and ground processes. GEMFLO translates the user’s responses into mathematical variables and expressions that populate the generic simulation model. The variables and expressions can represent processing times, resource capacities, status variables, and other process parameters needed to configure a simulation model that reflects the ground processing flow and requirements of a specific RLV. Upon execution of the model, GEM-FLO puts out data on many measures of performance, including the flight rate, turnaround time, and utilization of resources. This information can serve as the basis for determining whether design goals can be met, and for comparing characteristics of competing RLV designs.
TOP technologies for 2005AERONOV05_0311/1/2005
A look back at some of the most significant technological innovations in the news during the past year, as deemed by readers and editors. MIT researchers have developed and tested an aircraft-guidance system that allows a pilot in one plane to guide another, separate UAV by speaking commands in English. The system allows the pilot to interface with the UAV at a high level, not just “turn right, turn left” but “fly to this region and perform this task,” according to Boeing. The pilot essentially treats the UAV as a wingman.
SCOUT: EVA Capabilities of the Space Construction and Orbital Utility Transport2004-01-22957/19/2004
The University of Maryland has performed a detailed design for the space equivalent of an atmospheric diving suit. The Space Construction and Orbital Utility Transport (SCOUT) is a small single-person spacecraft, with all necessary utilities for extended sorties away from the host station. Through a pair of AX-5 style space suit arms integrated into the cabin wall, as well as a trio of dexterous manipulators, the SCOUT operator can directly interact with the work site environment, performing spacecraft servicing, structural assembly, or other tasks traditionally done by an astronaut in a space suit. Originally designed as an augmentation to the NASA Gateway station architecture for the Earth-Moon L1 system, studies indicate that a SCOUT-type EVA system would represent a substantial benefit to International Space Station operations as well. Due to the integrated robotics system, ISS extravehicular operations, which nominally require two EVA crew and one IVA robotics operator, can be done with a single SCOUT pod unaided. One of the requirements to allow safe single-pod operations is a high-reliability system to ensure crew survival. To this end, SCOUT incorporates several design features to increase mission assurance and maximize the probability of crew survival following a catastrophic failure. Since SCOUT is designed around an 8.3 psi cabin pressure, there are no prebreathe requirements prior to start of operations. This will allow a second SCOUT pod to be kept on “ready alert” at the station, with its operator performing other tasks but ready to react in a contingency. The second SCOUT safety feature is the adoption of an innovative “bail-out” system. In the event of a failure which renders SCOUT uninhabitable, in less than a minute the operator can deploy an emergency bail-out system, normally kept in a small package on the SCOUT hull. A single valve actuation will inflate an all-fabric escape suit, consisting of a simple cylindrical body with polycarbonate face plate and adjustable-length arms, mounted to the SCOUT cabin via a pressure hatch. The operator will then move into the escape suit, close the hatch, then detach from SCOUT. The system provides three hours of life support, along with SAFER-style cold gas thrusters for mobility. Between the second SCOUT pod on ready alert and the self-rescue capability of the escape suit, a probabilistic risk assessment shows a 99.9% chance of performing a 600-EVA mission model without loss of crew. Additional systems have also been designed to extend the operating range of the SCOUT system. A docking module was designed to support two SCOUT pods, providing docking interfaces to the host station and SCOUT-specific resupply/repair capabilities. The docking module docks to space station through the use of an International Space Station common berthing mechanism (CBM). An extended mission package provides support for SCOUT in remote operations, extending sortie times from 11 hours to several days. In conjunction with an orbital maneuvering vehicle, the extended mission package would allow an ISS-based SCOUT to be used for human servicing at geostationary orbit, and from an L1 base would allow SCOUT operations in lunar orbit.
Akin, David L., Bowden, Mary L.
New Space Transportation Architectures Based on the Use of Planetary Resources2004-01-23137/19/2004
Space transportation today is undertaken nearly entirely using vehicles launched from Earth in which all elements of a mission are integrated on Earth. Missions to low Earth orbit, Geosynchronous orbit, the Moon, Mars, Jupiter, etc., all are launched directly from Earth. Missions requiring large changes of velocity may be staged to gain efficiency, but still everything has to be launched from Earth. As a consequence, missions that emplace rather small payloads on the Moon, for example, Apollo, require very large rockets on Earth. Architectures for exploration beyond low Earth orbit can be dramatically changed if propellants can be produced on the Moon, Mars or small bodies and provided to spacecraft on planet surfaces and at fuel depots in space. Increasingly sophisticated models are being developed that include propellant production, in-space storage and transportation systems that can be used to assess the benefits (and risks) of architectures based on the use of planetary resources. We demonstrate the utility of these models using lunar base and human exploration of Mars scenarios.
Duke, Michael B., Blair, Brad R., Ruiz, Begoña, Diaz, Javier
Guidelines for Developing Spacecraft Structural Requirements; A Thermal and Environmental Perspective2004-01-22857/19/2004
Spacecraft are typically designed with a primary focus on weight in order to meet launch vehicle performance parameters. However, for pressurized and/or man-rated spacecraft, it is also necessary to have an understanding of the vehicle operating environments to properly design the pressure vessel. Proper sizing of the pressure vessel requires an understanding of the space vehicle’s life cycle and compares the physical design optimization (weight and launch “cost”) to downstream operational complexity and total life cycle cost. This paper provides an overview of some major environmental design drivers and presents a generic set of cracking pressures for both positive and negative pressure relief valves that encompasses environmental effects for a variety of launch and landing sites. In addition, an example is provided to compare up-front launch weight penalties against downstream operational constraints.
Holladay, Jon, Day, Greg, Gill, Larry
Multi-faceted Approach for Initial Volume Determination for Smaller Lightweight 2 nd Generation Space Planes2003-01-23477/7/2003
The SLI proposed requirements for a Crew Transfer Vehicle, CTV, have evolved from a Shuttle-like multipurpose vehicle concept to a vehicle with a requirement to merely transport 3-5 crewmembers (a space taxi) to the International Space Station. In an effort to minimize the weight and cost of this Orbital Space Plane, OSP (previously known as CTV) and to optimize the total 2nd Generation Reusable Launch Vehicle approach, the requirements for OSP have dictated a much smaller crew cabin than the Shuttle astronauts have utilized. The challenge to the human factors engineers is to develop a set of derived requirements for the crew volume. Several analysis approaches have been used, compared, and evaluated against the key drivers. The drivers of these approaches are the physical and psychological limits of humans, operational requirements, time on orbit, task requirements, crew accommodations/technologies, packaging, volume layout and application of lessons learned. This paper both describes the approaches and rationales used to develop initial crew volume requirements for the various OSP design reference missions and summarizes the resulting requirements identified. While significantly smaller, the recommended volume requirements will aid vehicle designers during the concept development and insure enough volume is allocated for humans. An additional benefit is the pushing back on questionable/soft system requirements for trade decisions affected by vehicle size and weight.
Lytle, Bill
NASA's Space Launch Initiative: A Program Overview2002-01-12673/4/2002
For fiscal year 2001 (FY2001), the National Aeronautics and Space Administration (NASA) reorganized its efforts to develop a 2nd Generation Reusable Launch Vehicle (RLV) under the new Space Launch Initiative program. The stated goal of the Space Launch Initiative (SLI) is the development of new technologies over a five-year period that will lead to a decision mid-decade on whether to move forward with a new design, which will eventually replace the space shuttle. This new vehicle will be 100 times safer and 10 times cheaper than today's launch systems. In its FY2001 budget, NASA requested and received $290 million and for FY2002 requested $475 million, a 64% increase although lower than the $610 million NASA initially planned to request for FY2002. The total planned budget is approximately $4.4 billion through FY2005. The capabilities of the resulting launch vehicle will be a failure rate of 1 in 10,000 and $1000 per pound to low earth orbit. To achieve this safety margin, it is widely accepted that the new vehicle will require a complete crew escape system. By comparison, the space shuttle only has escape capabilities to 20,000 feet. Other capabilities include 10 person launch crews (compared to 170 today), one-week turnaround time (compared to five months) and hundreds of flights per year (compared to fewer than 10 times per year today).1 The question is, can SLI's research funds lead to technology which will be able to develop a 2nd generation RLV capable of all (or some) of the above listed objectives? Also, how will SLI and the 2nd generation RLV affect space commerce?
Rohrbacher, John J.
Design of the Thermal Control System for the Space Technology 5 Microsatellite2001-01-22147/9/2001
The New Millennium Program’s (NMP) Space Technology 5 (ST-5) Project, currently in Phase B of the design process, is slated to launch three 20-kg class spin stabilized microsatellites in late 2003. The proposed orbit is highly elliptical and could result in an earth shadow eclipse of almost 2 hours. Although ST-5’s maximum eclipse is only 2 hours, future missions could involve eclipses as long as 8 hours. As spacecraft size, mass, and available resources decrease and eclipse duration increases, thermal engineers will be challenged to design simple but robust thermal control systems that meet temperature requirements for all phases of the mission. In addition, future similar missions may involve large “fleets” of such small spacecraft, which, for cost and I&T reasons, must be almost identical in design. Such spacecraft will require a generic but robust thermal control design that is suitable for a wide variety of thermal environments. This paper presents the results of a study of three design concepts and preliminary analysis of the design selected for ST-5.
Douglas, D., Michalek, T., Swanson, T.
Program Architecture for the Robotic Exploration of Mars2001-01-21377/9/2001
NASA has recently completed the definition of a new architecture for the exploration of Mars. This paper will present a summary of the new Mars Exploration Program (MEP) architecture, along with a description of the resulting mission queue and science investigations.
Lavery, Dave
Assembly Techniques for Space Vehicles2000-01-30289/19/2000
Assembly techniques for the majority of expendable and reusable launch vehicles have not changed much over the last thirty years. Some progress has been made, specifically on new programs, however, improvements on existing expendable launch vehicle production lines can be difficult to justify; even more so for one or two reusable vehicles. This presentation will focus on techniques and systems used for manual and automated assembly of expendable and reusable launch vehicle primary structures. Today's assembly is characterized by manual operations involving fixtures and templates, and all tasks are carried out primarily with single function hand tools. Typical assembly approaches used for metallic and composite primary structures will be discussed. Potential opportunities for process improvements utilizing advanced hand tools, mechanized and/or automated equipment will be addressed.
Sarh, Branko
Mobile System for Control of a Remote Rocket-Launching RangeTBMG-297784/1/1999
The Wallops Flight Facility of the Goddard Space Flight Center has designed and built in-house a Mobile Range Control System (MRCS), which is a self-contained system to be deployed in support of rocket launches at remote ranges in cases in which termination of flight may be required for safety purposes. The MRCS includes data-acquisition subsystems, real-time data-computation subsystems, range-safety displays, command/destruct transmitters, and supporting communication subsystems, all together providing for remote range control.
The Role of Castings in Part Consolidation9722226/3/1997
Parts consolidation is receiving renewed interest from airframe producers as a means of reducing design and manufacturing costs, weight, and maintenance. Furthermore, assemblies designed as monoliths enable use of determinant assembly methods for construction. Design for Manufacturing and Fewer-and-Simpler Parts are two initiatives which focus on the relationship between part count and total cost. How do castings compare with competing technologies in delivering a solution to part count reduction? Numerous applications are investigated and contrasted against other manufacturing processes. What do these case histories tell us about where to look for future successes?
Scoville, Tim W.
Virtual Reality Control of On-Orbit Spacecraft9615837/1/1996
The Ranger Telerobotic Flight Experiment is a highly complex teleoperated spacecraft, requiring direct human control of 36 major degrees of freedom. The University of Maryland Space Systems Laboratory and the NASA Ames Research Center are cooperating on the development of a virtual reality control station to streamline human interfaces with the Ranger spacecraft. This describes the design and integration of the Ranger Command Chair, a system incorporating fully immersive helmet-mounted stereo displays with head tracking, hand tracking for direct positional control, and supplemental controls and displays to allow a single operator to functionally control the entire vehicle. This system is currently undergoing tests with the Ranger Neutral Buoyancy Vehicle, a functionally identical vehicle used for systems development and flight operations simulations. Current status of the system is presented, along with plans for direct comparisons between virtual reality and more traditional control modes.
Akin, David L., Hine, Butler
Thermal Design of the Far Ultraviolet Spectroscopic Explorer Satellite Bus9615747/1/1996
A wide range of environmental exposures, stringent payload interface conditions, a low risk requirement, low allowable heater power, constraints of a fixed price contract and aggressive schedule presented a challenge in developing the FUSE bus (spacecraft) thermal design. The bus provides power, attitude control and telemetry for the satellite, which includes the bus and instrument payload. The thermal design that evolved is remarkably self-regulating. This is attributed to the synergistic effect of a compact structure that allows cross-coupling of radiators with different exposures in addition to the advantages of a large louver. This paper discusses the design approach, key thermal control features, supporting analyses and trade studies, and how predicted results compare with requirements for the design envelope and beyond.
Wasson, David, Ducas, William
Thermal Design of the ORBCOMM Constellation Spacecraft9614917/1/1996
The thermal design strategy is discussed as it relates to the production of up to 34 identical small satellites in a relatively short period of time. Tight production and launch schedules and the need to design for low mass, risk, and cost presented a design challenge for all disciplines. A specific arrangement of passive thermal control features, including ITO-coated AgTef covered structure radiators, MLI, and software controlled heaters established a robust design. Thermal modeling of the bus and unique antenna are presented including a comparison between the predicted and required component temperature ranges. Also described are the primary mission objective, the spacecraft configuration, requirements and design drivers, mission environments, and design parameters.
DeMauro, Frank, Ducas, William
The Alternative Launcher Question: Should the U.S. Shuttle and Titan 4 Rocket Be Replaced?94212110/1/1994
Debate continues as to whether the current launch programs, namely the U.S. Space Shuttle and Titan Rocket, have passed their level of effectiveness and economic practicability. Last fall, at a meeting discussing the United States' ability to launch into space between NASA, the Air Force and the Defense Department, the experts agreed on one primary item: the current systems are inefficient and uneconomical. This agreement came despite the years of study and shifting policy positions that have left the three organizations with sharply opposing views over the direction the country should take in launch vehicle development. It is believed by a growing number of insiders that single-stage-to-orbit vehicles, once developed, could provide a more reliable, and cost-saving method of space transportation.
Burleson, Daphne
Post-Launch Application of EP MAPS Thermal Models for Improved On-Orbit Performance9414366/1/1994
The importance of developing test correlated analytical models, of critical or unique spacecraft hardware, is not limited to pre-flight design verification. Such thermal models can also be extremely useful tools in assessing on-orbit operational and temperature anomalies. This paper discusses the application of test correlated thermal models, developed for a complex electro-mechanical system, in support of on-orbit operational replanning in response to unexpected mechanism movement and electronics temperature levels. The modeling effort utilized a recently developed routine for chaining coordinate systems in TRASYS (Thermal Radiation Analysis System). Results from the modeling provided detailed data, which complemented the limited telemetry and supported the operational replanning to ensure acceptable performance would be maintained throughout the mission.
Wasson, David, Ducas, William
On-Orbit Thermal Performance Testing Of The Explorer Platform9415486/1/1994
In order to characterize the thermal performance of the spacecraft at attitudes beyond initial constraints and to expand the operational envelope, on-orbit testing was performed. Plans and tradeoffs in preparing for the testing are discussed. Results are presented and compared with analytical predictions. Although the payload and bus sections were only separately thermal vacuum tested prior to flight, results from the on-orbit testing indicate the integrated thermal design is robust. One thermal anomaly was discovered which is attributed to specular reflections from a radiator. The influence of the on-orbit testing results on spacecraft continuing operations is also discussed.
Wasson, David, Ducas, William
Two Stage to Orbit Airbreathing and Rocket System for Low Risk, Affordable Access to Space9411684/1/1994
The US space program is facing the dilemma of the federal government reducing in size, the Congress asking for lowered costs, and the US market share of commercial launches declining. While several new launch vehicle options have been studied and advocated, a national plan has yet to be adopted. Despite this, there may be compelling solutions that await discovery. This paper suggests a particular TSTO launch system may solve the dilemma, but only if some of the past presumptions and guidelines are viewed as impediments to be overcome instead of “realities”.
Gregory, Tom, Bowles, Jeff, Ardema, Mark
What Should the United States do after the Space Shuttle?9410373/1/1994
In the past decade, the space shuttle has been the key factor for the United States manned space exploration. In fact the space shuttle is the only means in which the United States government can send humans into space. However, the space shuttle's life-expectancy is due to expire around the year 2005. In preparation for the end of the space shuttle era, we, as a country, must decide what type of future space vehicle is appropriate to accomplish our future national goals in space. There are many public policy alternatives to the question: ‘What will replace the space shuttle?’ First, the United States could try a conservative approach to space exploration by developing and using an unmanned vehicle. Second, the government could opt for utility by developing a mixed fleet of launch vehicles. Third, the United States could try to modify and update the current space shuttles with new technology. Fourth, the United States could choose to invest its money in more ‘exotic’ space vehicle programs such as the Single-Stage-To-Orbit(SSTO) space plane and the Two-Stage-To-Orbit(TSTO) space plane. Lastly, the United States could try to initiate talks with other countries concerning an international space agency that could pool the finances and resources into one unified space program. In my final recommendation, I would first look into a possible international cooperation for future funding and operation of space transportation. However, if this first objective is unable to produce any type of cooperation within a couple of years, I would initiate a parallel future space vehicle program that would involve most of the modification of the space shuttle option and all of the mixed fleet option. Along with these main public policy recommendations, I also recommend some administrative suggestions that could prove vital in trying to carry out the public policy of future space vehicles.
Yamada, Eric Ricky
Egress Testing of the HL-20 Personnel Launch System9320397/1/1993
Human factors egress testing of the HL-20 Personnel Launch System, a reusable flight vehicle for Space Station crew rotation, was conducted in both the vertical (launch) and horizontal (landing) positions using a full-scale model. Ingress and egress of 10-person crews were investigated with volunteers representing a range of heights. For both the vertical and horizontal positions, interior structural keels had little impact on egress times which were generally less than 30 seconds. Wearing Shuttle partial pressure suits required somewhat more egress time than when ordinary flight suits were worn due to the larger helmet of the Shuttle suit.
Willshire, Kelli F., Simonsen, Lisa C.
Thermal Control Issues of the Assured Crew Return Vehicle (ACRV)9320547/1/1993
The new challenges of permanently inhabited orbital stations include the need for immediate, safe return to Earth of the station crew. In particular, in the frame of the Space Station Freedom (SSF) program, three potential emergency situations have been identified: ill/injured crew member return crew evacuation due to uninhabitability of SSF crew return due to unavailability of Space Transportation System It is recognised that station crew rescue/recovery by means of the U.S. Space Transportation System (STS) is not feasible since the time needed to setup the rescue mission would be too long for the assigned requirements. It has therefore been decided to develop an Assured Crew Return Vehicle, permanently docked to SSF and able to re-enter its crew (in total or in part) within assigned time constraints. This paper concentrates on the description of the three thermal subsystems present inside the ACRV: the Thermal Protection Subsystem (TPS), the Thermal Control Subsystem (TCS) and the Environmental Control and Life Support Subsystem (ECLSS). The subjects investigated are the system approach in the management of these three subsystems and their major design features. Finally, the open issues are identified and the activities foreseen in the near future are presented.
Burgio, Fabrizio, Ferro, Claudio, Russo, Adolfo
U.S. Acquisition of Soviet Rocket Technology A Presentation of the Arguments Surrounding the RD-1709310143/1/1993
For the last several years, the Soviet Union, now the Commonwealth of Independent States (CIS), has offered the RD-170 rocket engine for sale to the West. The RD-170 is the most powerful and most technologically advanced rocket engine in production in the world. However, the U.S. presently has no policy regarding the acquisition of Soviet rocket technology such as the RD-170. In order to develop an effective policy, the U.S. must first determine if an application for RD-170 class engines exists, and then weigh the advantages of acquisition such as reliable and cost effective heavy lift capability versus the disadvantages such as exporting U.S. jobs. There are several possible methods of acquisition, although joint U.S.-CIS production of the RD-170 is the most politically viable as it would create U.S. jobs and support economic reforms in the CIS at the same time.
Braddom, Steven R.
An Electromechanical Actuation System for an Expendable Launch Vehicle9291128/3/1992
A major effort at the NASA Lewis Research Center in recent years has been to develop electromechanical actuators (EMA's) to replace the hydraulic systems used for thrust vector control (TVC) on launch vehicles. This is an attempt to overcome the inherent inefficiencies and costs associated with the existing hydraulic structures. General Dynamics Space Systems Division, under contract to NASA Lewis, is developing 18.6 kW (25 hp), 29.8 kW (40 hp), and 52.2 kW (70 hp) peak EMA systems to meet the power demands for TVC on a family of vehicles developed for the National Launch System. These systems utilize a pulse population modulated converter and field-oriented control scheme to obtain independent control of both the voltage and frequency. These techniques allow an induction motor to be operated at its maximum torque at all times. At NASA Lewis, we are building on this technology to develop our own in-house system capable of meeting the peak power requirements for an expendable launch vehicle (ELV) such as the Atlas. Our EMA will be capable of delivering 22.4 kW (30 hp) peak power with a nominal of 6.0 kW (8 hp). This system differs from the previous ones in two areas: 1) the use of advanced control methods, and 2) the incorporation of built-in-test. The advanced controls are essential for minimizing the controller size, while the built-in-test is necessary to enhance the system reliability and vehicle health monitoring. The ultimate goal of this program is to demonstrate an EMA which will be capable of self-test and easy integration into other projects. This paper will describe the effort underway at NASA Lewis to develop an EMA for an Atlas class ELV. An explanation will be given for each major technology block, and the status of the overall program will be reported.
Burrows, Linda M., Roth, Mary Ellen
Power Systems for the Mars Environmental Survey (MESUR) Mission9291248/3/1992
Mars Environmental Survey Mission (MESUR) is intended to be a low cost, near term mission to study the chemical composition of Martian surface, structure and circulation of Mars' atmosphere, and the structure and dynamics of Mars' interior. To meet the science objectives of the mission, a network of 16 landers will be placed at various latitudes and longitudes of Mars. The paper identifies various options for powering the landers and lists the attributes of each option. The current strategy is to precede the lander launch and deployment with an engineering demo mission called the Pathfinder which would demonstrate the landing strategy and the engineering subsystems. The paper briefly describes the challenges involved in the power system development for the Pathfinder mission.
Shirbacheh, Mike, Chmielewski, Art B.
NASA Requirements and Applications Environments for Electrical Power Wiring9292478/3/1992
Serious problems can occur from insulation failures in the wiring harnesses of aerospace vehicles. In most recorded incidents, the failures have been identified to be the result of arc tracking, the propagation of an arc along wiring bundles through degradation of insulation. Propagation of the arc can lead to the loss of the entire wiring harness and the functions which it supports. While an extensive database of testing for arc track resistant wire insulations has been developed for aircraft applications, the counterpart requirements for spacecraft are very limited. This paper presents the electrical, thermal, mechanical, chemical, and operational requirements for specification and testing of candidate wiring systems for spacecraft applications.
Stavnes, Mark W., Hammond, Ahmad N.
Design and Evaluation of a Payload to Support Plant Growth onboard COMET 19213897/1/1992
P-MASS, the Plant-Module for Autonomous Space Support, is designed to support and provide life support for a variety of plants, algae and bacteria in low earth orbit during the maiden flight of COMET-1. The first launch is scheduled for early 1993. With a nominal mission duration of 30 days in microgravity, P-MASS will bridge the gap between the shorter duration experiments possible onboard the NSTS Space Shuttle (approximately 14 days) and the future Space Station Freedom for space biology applications. Environmental data and video images are collected, stored onboard and downlinked daily. In addition, the payload and all specimens will be returned for ground analysis with the recovery system (reentry capsule). P-MASS is designed within a payload envelope of 0.28 x 0.22 x 0.32 m (19.71) and a mass of approximately 20 kg. A total of 115 Watt electric power is available continuously for the Plant-Module (60 W lighting, 40 Watt cooling, 15 W housekeeping). Quartz halogen bulbs, or alternatively a hybrid light emitting diode lighting system (ultrabright red LED) provide 40 W/m2 photosynthetically active radiation (PAR) for the 0.06 m2 growth area. In addition to higher plants, photosynthetic and nonphotosynthetic micro-organisms as well as plant cultivare/tissue cultures are supported. An active, solid state cooler allows the interdependent control of humidity and temperature, at the same time maintaining soil moisture by passive liquid management. Carbon dioxide and oxygen concentrations are monitored and adjusted physically or biologically. Ground tests have verified the design concept. Plant growth experiments and life support performance tests are presently being conducted. These performance data will be used together with ground controls for on-orbit performance analysis. P-MASS, though simple and reliable in design, can provide valuable information and experience in gravitational and space biology with applications directed for future life support systems.
Luttges, M. W., Robinson, M. C., Stodieck, L. S.
Arianespace Launches Lightsats9119969/1/1991
This paper presents the means Arianespace provides for launching small satellites into geostationary transfer orbit (GTO) or low Earth orbit (LEO) and reviews actual as well as potential applications for lightsats. Small satellites weighing less than 50 kg are microsatellites. Satellites with a mass of a few hundred kilograms not exceeding 1 ton are minisatellites. Microsatellites are typically built by universities, research laboratories or radio amateur organizations and do not constitute a commercial market. Minisatellites on the other hand may have all the functions and the operational life-span of large satellites and may be used for a wide variety of missions.
Brand, Dieter
The HL-20 Lifting-Body Personnel Launch System9119709/1/1991
For several years the NASA Langley Research Center has conducted in-depth research in supporting technology advancement for a concept which could complement the Space Shuttle operation and ensure the ability to transport people to and from earth orbit. The concept is called the HL-20 Lifting-Body and it has been defined as an option for future development as a Personnel Launch System (PLS). This paper will describe early lifting-body research, expected PLS mission requirements, the HL-20 concept design status, and those features which enhance aerodynamic and aerothermodynamic performance, operation efficiency, maintainability, reliability, and crew safety. The HL-20 concept evolved from early lifting-body research in the 60's and 70's and has been designed for the primary mission of changing the Space Station Freedom crew. It is sized to accommodate eight passengers plus a flight crew of two. The duration of the mission is 3 days. About 29 ft in length, the vehicle has a landing weight of 22000 lb. It is launched vertically, mounted on an expendable or partially reusable booster and has a hypersonic lift-to-drag ratio of about 1.4 with an entry cross-range of 1100 nautical miles to provide flexibility in choice of landing sites for each orbit and in opportunities for landing. Landing is horizontal on runways 10000 feet or longer. Considerable research effort has advanced the HL-20 to a fairly mature design. A broad range of wind tunnel testing has provided a substantial data base for understanding the aerothermodynamic performance and these tests have been complemented by numerous computational flow-field studies. Structural and subsystem design has focused on features which offer operational simplicity with low maintenance costs and rapid vehicle processing. Efficiency in operation is achieved through the use of airline approaches to overall system layout and access coupled with built-in test and health monitoring instrumentation. Computer-based flight simulations have involved experienced pilots and astronauts, and the HL-20 concept proved to be relatively easy to fly and to land. A full-scale model of the concept has been constructed with an interior for conducting crew accommodation studies, ingress and egress, pilot visibility, and other man machine interface investigations. Results of the HL-20 PLS research to date show that the concept has definite advantages for efficiently satisfying future needs for assured manned access to space. The vehicle is designed with operational efficiency, low life-cycle costs, reliability, and safety as the primary criteria. Should there be a decision to develop and operate the vehicle, it has been defined with a substantial technical foundation for reducing the risk of program success.
Stone, Howard W., Piland, William M.
Geostationary Earth Observatories - Key Elements of NASA's “Mission to Planet Earth”9119979/1/1991
The Marshall Space Flight Center (MSFC) has been given the responsibility for conceptual development of the Geostationary Earth Observatory (GEO) element of NASA's Mission to Planet Earth program. Because these multi-instrument geostationary satellites will orbit over given points on the ground, they will each provide continuous observation of large regions of the Earth and will complement other data gathering facilities in low Earth orbit (LEO) such as the polar platforms of the Earth Observing System (EOS) and the Earth Probe satellites which operate in a variety of specialized LEO's. These various systems will operate over a 15-year period to obtain data with unprecedented global and temporal coverage. Because of their Earth-fixed position, the GEO instruments will provide high temporal resolution while the LEO instruments will provide data having higher spatial and spectral resolution. These data will be used to define the hydrologic, biogeochemical, and energy cycles which constitute the Earth system. Understanding these cycles and developing the capability to predict their course are the ultimate goals of Mission to Planet Earth. In response to the recommendations of the GEO Science Steering Committee, several key instruments have been provisionally identified to provide the required scientific observations. Some of these instruments were chosen to parallel certain instruments planned for the EOS polar platforms allowing direct intercomparisons. Other instruments, including possibly a set of “operational” sensors and certain dedicated Principal Investigator (PI) sensors, will also be included on GEO. Currently, MSFC is conducting in-house and contracted design studies of the GEO spacecraft based on accommodating the provisionally selected instruments. Stringent instrument pointing and stability criteria are major observatory design drivers. The observatories are baselined for launch on the Titan IV/Centaur but would be a candidate for the National Launch System (NLS) should it become available in the required timeframe. Development of a data and information system which is responsive to the needs of the Earth Science community is a critical part of the early design definition studies now underway. As a goal, data from all GEO's would be available in near-real time to the research community of government, university, and private users. A variety of concepts is under investigation to achieve this goal including satellite linking and ground system linking. It is anticipated that GEO will evolve into a multinational program. One concept calls for five GEO's employed simultaneously around the Earth, three by the United States and two by nations such as Japan or the European Space Agency (ESA). Current technology and engineering studies indicate that the first GEO can be ready for launch shortly after the year 2000. This paper discusses in more detail the scientific rationale, required instrumentation, observatory configuration, and data system of the GEO program.
Snoddy, William C., Keller, Vernon W.
APPROACHES TO REDUCED LAUNCH OPERATIONS COSTS9018779/1/1990
Current US expendable launch vehicles evolved from ICBMs (Thor, Atlas, Titan) which were primarily performance (payload to orbit) driven. They are expensive and, although originally highly responsive, have been modified so extensively that they now have relatively poor operability characteristics (responsiveness, flexibility, robustness, resiliency, etc.). This paper examines past/existing systems to derive lessons learned and operations drivers which need to be mitigated on new systems. It surveys requirements of several new/proposed systems and suggests approaches for low cost operations for these and any other new systems. Strategies include trading weight for dollars, system simplification, selective automation, modernization (hardware and software, ground and vehicle system), and application of (military) aircraft operations and design concepts. The paper concludes that operability in launch systems is achievable. It requires 1) attention to design early in development, with follow through of some up front dollars, 2) modest technology development, and 3) a new mind set in performing launch operations.
Hopkins, Jerry L.
Design and Development of Composite Fairing Structures for Space Launch Vehicles9018369/1/1990
Current space transportation systems such as expendable launch vehicles (ELVs) and the reusable Space Transportation System (space shuttle) are very expensive. In some instances they are based on 10 to 20 year old technologies. Newer, lower cost technologies must be applied to designing and manufacturing the next generation of vehicles. Competing effectively in the launch vehicle industry requires an order-of-magnitude reduction in the cost per pound of payloads delivered to orbit. Payload fairings are critical structural elements in all ELV systems. In addition to carrying and transmitting vehicle loads, they also protect payloads from severe launch and in-flight environments. Developing improved fairing hardware and the associated structural, thermal, acoustic, and separation subsystems is a major undertaking. It requires extensive design, analysis, testing, and systems integration activity. To maintain a competitive posture in the launch service industry, three years ago McDonnell Douglas Space System Company (MDSSC) initiated a research and development program on composite fairings. The program investigated and refined design and analysis, process techniques, and fabrication methods for large diameter composite fairings (1,2).* Substantial progress was achieved in composite fairing material selection, design and analysis, and manufacturing methods characterization. Eight composite fairing configurations with different constructions, and five aerodynamic forebody shapes with improved performance characteristics, were evaluated and studied. A final fairing configuration was selected for further study and the fabrication of a demonstration/test article is underway. This paper presents the composite fairing structural alternatives investigated and summarizes the results of the major trade studies undertaken.
Shen, Frank, Pope, Dennis
Facilities for Animal Research in Space with Special Reference to Space Station Freedom9013037/1/1990
The facilities being planned for animal research on Space Station Freedom are considered in the context of the development of animal habitats from early ballistic and orbital flights to long-term missions aimed at more detailed scientific studies of the effects of space conditions on the vertebrate organism. Animal habitats are becoming more elaborate, requiring systems for environmental control, waste management, physiological monitoring, as well as ancillary facilities such as a 1-G control centrifuge and a glovebox. Habitats in use or to be used in various types of manned and unmanned spacecraft, and particularly those planned for Space Station Freedom, are described. The characteristics of the habitats are compared with each other and with current standards for animal holding facilities on the ground.
Kishiyama, Jenny S., Arno, Roger D.
LifeSat: A Satellite for Space Biological Research9012257/1/1990
The LifeSat Program addresses the need for continuing access by biological scientists to space experimentation by accommodating a wide range of experiments involving animals and plants for durations up to 60 days in an unmanned satellite. The program will encourage interdisciplinary and international cooperation at both the agency and scientist levels, and will provide a recoverable, reusable facility for low cost missions addressing key scientific issues that can only be answered by space experimentation. It will provide opportunities for research in gravitational biology and on the effects of cosmic radiation on life systems. The scientific aspects of LifeSat addressed in this paper are drawn from the science documents prepared by the Radiation Biology Working Group and the LifeSat Science Working Group, an international working group with scientific representatives from the Canadian Space Agency (NRCC), the European Space Agency (ESA), the German Space Agency (DLR), the Japanese Space Agency (NASDA), the French Space Agency (CNES), and the United States Space Agency (NASA).
Halstead, Thora W., Morey-Holton, Emily R.
LifeSat-Program Overview9012227/1/1990
LifeSat is a reusable reentry satellite for use by the National Aeronautics and Space Administration (NASA) and the international space life sciences community. It will be employed beginning in late 1994, to understand the effects of the space environment (i.e., high energy space radiation and microgravity) on biological systems. This paper describes the program for LifeSat.
Gilbreath, William P., Dunning, Robert W., Richardson, Michael L.
Shuttle - C: Trading Performance Margin for Reduced Cost8923349/1/1989
The preliminary design of a heavy lift launch vehicle called Shuttle - C is currently under-way to provide over 100,000 lbs (45,455 kg) pay load capability to a low earth orbit of 220 nautical miles (408 km) in the early 1990's. Although derived from the Space Shuttle (Space Transportation System or STS) concept using the same elements of External Tank (ET), Solid Rocket Boosters (SRB's), and main engines (SSME's), the Shuttle - C vehicle is an expendable, unmanned launch vehicle. The program ground rules require a minimum of engineering design, development, test and evaluation (DDT&E) cost, and a compressed development schedule to meet near term mission requirements. The Shuttle - C missions encompass a wide variety of payload types such as suborbital deployment of planetary vehicles, earth orbiting platforms, Centaur missions to Geosynchronous Orbit (GEO), and Space Station assembly and logistics resupply. The current performance of a 3 engine Shuttle - C exceeds 130,000 lbs (59,091 kg) to 220 nm (408 km) due to the removal of wings, tail section, crew cabin and man support systems. By trading this excess performance margin for design cost reductions, the Shuttle - C development presents some very unique design challenges not normally experienced in launch vehicle design. Additional performance provides significant advantages to the payload community by relieving critical weight targets and permitting use of less expensive materials, processes and simplier design solutions.
Harris, R. F.
The Titan IV launch Vehicle8923069/1/1989
Titan launch vehicles have been contributing to our national space accomplishments for more than 20 years. As the U.S. space program has grown, the Titan family has expanded to meet the changing requirements. The dependability and versatility of Titan vehicles have been demonstrated by their selection for various missions, including strategic intercontinental ballistic missile weapon systems, manned Gemini space flights, NASA interplanetary missions, and critical national security programs. This article summarizes the Titan legacy and is an overview of the newest Titan family member-the Titan IV.
Morrissey, Arthur C., O'Neill, Stephen T.
Reliable, Low Cost Launch Services8923079/1/1989
The delivery of small payloads to both suborbital and orbital space is a developing market for commercial launch services companies. The market size is becoming more defined and the rate of growth for the next several years is predicted. Since 1982. Space Services Incorporated (SSI) has had a demonstrated capability to meet the needs of small payload users. SSI's launch of Conestoga I in 1982, demonstrated the company's capability to design, procure, integrate, and launch a spaceflight vehicle from an unimproved launch site. SSI provides small payload launch services for a complete range of inclinations and altitudes as well as suborbital launch services for a variety of missions. The Conestoga family of launch vehicles has been designed using the same basic hardware in several configurations for different mission requirements. The Starfire family of sounding rockets uses similar design concepts. Starfire I was launched March 29,1989 for the University of Alabama in Huntsville's (UAH) Consortium for Materials Development in Space. SSI's company mission is to provide reliable, low cost access to space with launch schedules tailored to payload user requirements.
Armitage, Peter J.
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