Browse Topic: Expendable launch vehicles

Items (72)

Rockets re-engineered-a step further into the cosmos

17MEIP12_0112/1/2017

The 20th-Century nuclear arms race led to pioneering efforts in space technology, primarily driven by nations' desire to surpass one another for supremacy in spaceflight capability. Despite the largely deplorable motivations that drove the so-called “space race,” it resulted in a massive surge in aerospace engineering efforts that eventually led to the development of artificial satellites orbiting the earth, space probes that have explored the moon and other planets and the most challenging accomplishment: human spaceflight. After the first human spaceflight in 1961 by Yuri Gagarin of the USSR, and later the U.S.'s Alan Shepard, respectively the first-ever “cosmonaut” and “astronaut,” engineering efforts were dedicated mainly towards landing a man on the moon.

Vented Launch Vehicle Adapter for a Manned Spacecraft With “Pusher” Launch Abort System

TBMG-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 Software

1/1/2014

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 Series

TBMG-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 Space

13AERD0603_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 Vehicles

TBMG-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 Methods

AIR5109 (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 Operations

2011-01-250610/18/2011

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 Programs

2010-01-232110/19/2010

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 Safety

TBMG-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 Suborbital

TBMG-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

Investigation of Life Support and Habitability Requirements for a Pressurized Lunar Rover

2009-01-25057/12/2009

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

Husain, Syed-Ali A., Akin, David L.

The Future of Space Propulsion

TBMG-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 Operations

TBMG-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

TOP technologies for 2005

AERONOV05_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 Transport

2004-01-22957/19/2004

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

Akin, David L., Bowden, Mary L.

New Space Transportation Architectures Based on the Use of Planetary Resources

2004-01-23137/19/2004

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

Duke, Michael B., Blair, Brad R., Ruiz, Begoña, Diaz, Javier

Guidelines for Developing Spacecraft Structural Requirements; A Thermal and Environmental Perspective

2004-01-22857/19/2004

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

AEROJUN04_026/1/2004

The agency's new long-term space exploration program starts with a return to the moon and will ultimately enable future exploration of Mars and other solar system destinations. In early April, National Aeronautics and Space Administration (NASA) Administrator Sean O'Keefe testified before the U.S. Senate Subcommittee on Science, Technology and the Space Committee on Commerce, Science and Transportation regarding NASA's FY 2005 budget request. The occasion provided the first initial glimpse of how President Bush's vision for U.S. space exploration will be implemented by the agency. Input from members of Congress and others, as well as the findings of the Columbia Accident Investigation Board, have emphasized the importance of setting clear, long-term goals for the nation's human space flight program, with the deliberations forming the basis for the President's FY 2005 budget request for NASA, said O'Keefe. The FY 2005 NASA budget request is a little over $16.2 billion, a 5.6% increase

Multi-faceted Approach for Initial Volume Determination for Smaller Lightweight 2 ^nd Generation Space Planes

2003-01-23477/7/2003

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

NASA's Space Launch Initiative: A Program Overview

2002-01-12673/4/2002

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

Rohrbacher, John J.

Program Architecture for the Robotic Exploration of Mars

2001-01-21377/9/2001

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.

Design of the Thermal Control System for the Space Technology 5 Microsatellite

2001-01-22147/9/2001

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

Douglas, D., Michalek, T., Swanson, T.

Assembly Techniques for Space Vehicles

2000-01-30289/19/2000

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.

Mobile System for Control of a Remote Rocket-Launching Range

TBMG-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 Consolidation

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.

Thermal Design of the Far Ultraviolet Spectroscopic Explorer Satellite Bus

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 Spacecraft

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

Virtual Reality Control of On-Orbit Spacecraft

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

Akin, David L., Hine, Butler

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 Performance

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 Platform

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 Space

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?

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

Yamada, Eric Ricky

Egress Testing of the HL-20 Personnel Launch System

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)

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

Burgio, Fabrizio, Ferro, Claudio, Russo, Adolfo

U.S. Acquisition of Soviet Rocket Technology A Presentation of the Arguments Surrounding the RD-170

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 Vehicle

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

Burrows, Linda M., Roth, Mary Ellen

NASA Requirements and Applications Environments for Electrical Power Wiring

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.

Power Systems for the Mars Environmental Survey (MESUR) Mission

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.

Design and Evaluation of a Payload to Support Plant Growth onboard COMET 1

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

Luttges, M. W., Robinson, M. C., Stodieck, L. S.

Geostationary Earth Observatories - Key Elements of NASA's “Mission to Planet Earth”

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

Snoddy, William C., Keller, Vernon W.

The HL-20 Lifting-Body Personnel Launch System

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

Stone, Howard W., Piland, William M.

Arianespace Launches Lightsats

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.

APPROACHES TO REDUCED LAUNCH OPERATIONS COSTS

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

Hopkins, Jerry L.

Design and Development of Composite Fairing Structures for Space Launch Vehicles

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

Shen, Frank, Pope, Dennis

LifeSat-Program Overview

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.

LifeSat: A Satellite for Space Biological Research

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

Halstead, Thora W., Morey-Holton, Emily R.

Facilities for Animal Research in Space with Special Reference to Space Station Freedom

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.

Shuttle - C: Trading Performance Margin for Reduced Cost

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

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