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At least 37 records · Page 2

Advanced robotics for in-space vehicle processing

An analysis of spaceborne vehicle processing is described. Generic crew-extravehicular activity tasks are presented for a specific vehicle, the orbital maneuvering vehicle (OMV), with general implications to other on-orbit vehicles. The OMV is examined with respect to both servicing and maintenance. Crew-EVA activities are presented by task and mapped to a common set of generic crew-EVA primitives to identify high-demand areas for robot services. Similarly, a set of robot primitives is presented that can be used to model robot actions for alternative robot reference configurations. The robot primitives are tied to technologies and used for composing robot operations for an automated refueling scenario. Robotics technology issues and design accommodation guidelines (hooks and scars) for Space Station Freedom are described.

Smith, Jeffrey H.↗

Orbital storage and supply of subcritical liquid nitrogen

Subcritical cryogenic fluid management has long been recognized as an enabling technology for key propulsion applications, such as space transfer vehicles (STV) and the on-orbit cryogenic fuel depots which will provide STV servicing capability. The LeRC Cryogenic Fluids Technology Office (CFTO), under the sponsorship of OAST, has the responsibility of developing the required technology via a balanced program involving analytical modeling, ground based testing, and in-space experimentation. Topics covered in viewgraph form include: cryogenic management technologies; nitrogen storage and supply; cryogenic nitrogen cooling capability; and LN2 system demonstration technical objectives.

Aydelott, John C.↗

OTV fluid mangement systems

Design, performance, and technology issues associated with reduced gravity propellant management for orbital transfer vehicles (OTV's) are reviewed. The in-space cryogenic management state-of-technology significantly affects the overall confidence level associated with a resupply mission and propulsion performance. Cryogen resupply sequences, timelines, controls, and associated crew involvement are all affected by the technology state. Additionally, OTV propellant tankage configurations, tankage thermodynamic conditions, acceleration environment, propulsion interfaces, and instrumentation are significant factors. Basic propellant transfer phases examined that drive orbital servicing requirements include: (1) tankage preconditioning; (2) tankage chilldown; and (3) propellant fill. Propellant management support of the OTV propulsion phases includes engine restart requirements and orbital coast between engine burns. Technology activities in support of identified technology issues are reviewed.

Hastings, L.↗

Investigating Laser Beam Welding as an In-Space Joining Technique via Thermal Vacuum and Microgravity and Vacuum Experiments

In-space joining technologies are crucial for stimulating an in-space economy and for enabling sustained space exploration by in-space manufacturing and repair of metallic structures. Compared to brazing or soldering, in-space welding (ISW) can provide highly hermetic, strong, and complex joints, potentially without introducing additional material. However, the influence of extreme temperatures, reduced pressure, and reduced gravity on ISW is not yet fully elucidated. Several efforts at NASA are investigating laser beam welding (LBW) as a joining and repair method in both thermal vacuum (TVAC) and combined vacuum & reduced gravity environments. NASA Marshall Space Flight Center (MSFC) shepherded several ISW projects in its past, including the 1973 electron beam welding on Skylab, the 1989 low-power LBW on parabolic flights, and the unflown 1990s-era In-Space Welding Experiment. Recent parabolic flights and 3 degree-of-freedom ground testing build upon this heritage. A collaboration with the Ohio State University using NASA Langley Research Center (LaRC) hardware retrofitted for LBW achieved the first high-powered laser welds under vacuum and low gravity and developed a workforce capable developing such experimental hardware. A ground testing campaign at the MSFC Flat Floor simulated fit-up and welding representative of ISW in 3 degrees of freedom to emulate microgravity effects on inertial systems. One ongoing effort is a NASA Early Career Initiative project – Lunar Assembly and Servicing by Autonomous Robotics (LASAR). Ruggedized LBW components were developed by an external partner for use in TVAC. A TVAC-rated robotic arm was procured by MSFC and used in the first known robotic laser weld where all components save the laser generator were under vacuum. NASA Johnson Space Center (JSC) is advancing supervised autonomy of ISW. NASA LaRC continues to adapt their unique snowflake joint geometry, suitable for connecting segments in trusses and other structures, to LBW. Upcoming TVAC campaigns will focus on testing extreme temperatures, proving out autonomous operations, and demonstrating weld repair. Weld inspection will occur via a non-contact nondestructive evaluation (NDE) technique – electromagnetic acoustic transduction (EMAT). Another ongoing effort based at MSFC is the DISCMAN -- DIsk-Shaped Configurable and Modular vAcuum uNit – which seeks to development a compact, modular payload that can provide a vacuum environment while in a reduced gravity condition. This payload could support multiple in-space manufacturing developmental efforts, with the first demonstration technology being LBW. Currently, the design is targeting operations in the pressurized volume of a space station, but the payload could readily be adapted to other flight platforms such as parabolic or even suborbital vehicles. LASAR elucidates the effects of temperature and vacuum on LBW while DISCMAN probes those of vacuum and gravity. Through these complementary efforts, NASA is addressing the primary challenges of ISW across the space environment while simultaneously developing and maturing technologies including robotic systems and inspection methodologies for future practical implementation on the Moon and beyond. This approach is timely, as upcoming missions requiring sustained human presence in space will depend on reliable ISW capabilities to create robust metallic joints currently unproven in the space environment and to perform repairs in situ .

hypogravity↗

Metrics for in-space telescope assembly techniques

Reliable metrics are not yet available for choosing among human and robotic assets for space-based construction and servicing of large space telescopes. Using FAIR-DART as a reference design, we generated example event sequences for telescope assembly scenarios in enough detail to identify infrastructure assumptions and technology requirements. A systems trade among human and robotic techniques (human EVA, on-site telerobotic, ground-in-the- loop robotic, commanded or sequenced robotic, and autonomous/decision-making robotic) helped us to define key metrics in the human-robotic trade space, including quality, time, cost, and risk. Our methodology included examining representative end-member scenarios. Case A treated each step in the assembly sequence as if all other steps have no on-site human involvement, and Case B treated each step as if human EVA is already involved in all other steps. With this trade, we identified key enabling technologies and infrastructure for space-based assembly and servicing of large space telescopes.

space telescopes human and robotic in-space assemb↗

New luster for space robots and automation

Consideration is given to the potential role of robotics and automation in space transportation systems. Automation development requirements are defined for projects in space exploration, global services, space utilization, and space transport. In each category the potential automation of ground operations, on-board spacecraft operations, and in-space handling is noted. The major developments of space robot technology are noted for the 1967-1978 period. Economic aspects of ground-operation, ground command, and mission operations are noted.

Heer, E.↗

BASD: SIRTF Telescope Instrument Changeout and Cryogen Replenishment (STICCR) study

The Space Infrared Telescope Facility (SIRTF) is a long-life cryogenically cooled space-based telescope for infrared astronomy from 2 micrometer to 700 miocrometers currently under study by NASA-ARC, and planned for launch in approximately the mid 90's. SIRTF will operate as a multi-user facility, initially carrying 3 instruments at the focal plane. It will be cooled to below 2 K by superfluid liquid helium to achieve radiometric sensitivity limited only by the statistical fluctuations in the natural infrared background radiation over most of its spectral range. The lifetime of the mission will be limited by the lifetime of the liquid helium supply, and is currently baselined to be 2 years. The telescope changes required to allow in-space replenishment of the 2,000 liter superfluid helium tank are investigated. A preliminary design for the space services equipment is also developed. The impacts of basing the equipment and servicing on the space station are investigated. Space replenishment and changeout of instruments requires changes to the telescope design and preliminary concepts are presented.

Mord, A. J.↗

Cryogenic Fluid Management Technology Workshop. Volume 2: Roundtable Discussion of Technology Requirements

The Cryogenic Fluid Management Technology Workshop was held April 28 to 30, 1987, at the NASA Lewis Research Center in Cleveland, Ohio. The major objective of the workshop was to identify future NASA needs for technology concerning the management of subcritical cryogenic fluids in the low-gravity space environment. In addition, workshop participants were asked to identify those technologies which will require in-space experimentation and thus are candidates for inclusion in the flight experiment being defined at Lewis. The principal application for advanced fluid management technology is the Space-Based Orbit Transfer Vehicle (SBOTV) and its servicing facility, the On-Orbit Cryogenic Fuel Depot (OOCFD). Other potential applications include the replenishment of cryogenic coolants (with the exception of superfluid helium), reactants, and propellants on board a variety of spacecraft including the space station and space-based weapon systems. The last day was devoted to a roundtable discussion of cryogenic fluid management technology requirements by 30 representatives from NASA, industry, and academia. This volume contains a transcript of the discussion of the eight major technology categories.

Source record↗

In-space research, technology and engineering experiments and Space Station

The NASA Space Station will serve as a technology research laboratory, a payload-servicing facility, and a large structure fabrication and assembly facility. Space structures research will encompass advanced structural concepts and their dynamics, advanced control concepts, sensors, and actuators. Experiments dealing with fluid management will gather data on such fundamentals as multiphase flow phenomena. As requirements for power systems and thermal management grow, experiments quantifying the performance of energy systems and thermal management concepts will be undertaken, together with expanded efforts in the fields of information systems, automation, and robotics.

Tyson, Richard↗

SIRTF Telescope Instrument Changeout and Cryogen Replenishment (STICCR) Study

The Space Infrared Telescope Facility (SIRTF) is a long-life cryogenically cooled space-based telescope for infrared astronomy from 2 to 700 micrometers. SIRTF is currently under study by NASA-ARC (Reference AP) and planned for launch in approximately the mid 1990s. SIRTF will operate as a multiuser facility, initially carrying three instruments at the focal plane. It will be cooled to below 2 K by superfluid liquid helium to achieve radiometric sensitivity limited only by the statistical fluctuations in the natural infrared background radiation over most of its spectral range. The lifetime of the mission will be limited by the lifetime of the liquid helium supply, and baseline is currently to be 2 years. The telescope changes required to allow in-space replenishment of the 4,000-L superfluid helium tank was investigated. A preliminary design for the space services equipment was also developed. The impacts of basing the equipment and servicing on the space station were investigated. Space replenishment and changeout of instruments required changes to the telescope design. Preliminary concepts are presented.

Nast, T. C.↗

Mixed fleet assessment for on-orbit consumables resupply

Significant increases in the cost effectiveness and operational flexibility of in-space systems can be realized when the capability to replenish consumable fluids and propellants is incorporated into the designs of spacecraft, satellites, and orbiting platforms and laboratories. Reusable tankers are currently being designed for transporting fluids to space. A number of options exist for transporting the fluids and propellants to the space-based user systems. The fluids can be transported to space either in the Shuttle cargo bay or using Expendable Launch Vehicles (ELVs). Resupply can thus be accomplished either from the Shuttle bay, or the tanker can be removed from an ELV and attached to a carrier such as the Orbital Maneuvering Vehicle (OMV) or Orbital Transfer Vehicle (OTV) for transport to the user to be serviced. A third option involves locating the tanker at the Space Station or an unmanned platform as a quasi-permanent servicing facility which returns to the ground for recycling once its tanks have been depleted. This paper documents the impacts of a mixed fleet approach to consumables logistics to orbit. Both storable fluids and propellants, and superfluid helium, are considered. Current modular tanker designs for monopropellants, bipropellants and water for Space Station propulsion are discussed. Trade-offs in superfluid helium tanker sizes, shapes to fit the range of ELVs currently available, and boil-off losses associated with longer-term (greater than 6 months) space-basing, are addressed.

Eberhardt, Ralph N.↗

Retrievable Payload Carrier (RPC): Next generation Long Duration Exposure Facility

The Retrievable Payload Carrier (RPC) is described which is a multi-experiment, free-flyer spacecraft being privately developed to make in-space experimentation more accessible and economically feasible for research and development organizations. The carrier concept was derived from NASA's highly successful and flight proven Long Duration Exposure Facility (LDEF). The LDEF capabilities were enhanced to meet new customer requirements. This reusable payload carrier is planned for launch and retrieval by the space shuttle on a regular basis. The RPC's compact design facilitates flexible manifesting of the shuttle cargo bay space, thereby, permitting timely launches and retrievals. The vehicle is designed so that either the entire carrier can be retrieved from orbit, or individual experiment pallets can be removed and replaced in orbit. This gives customers even greater control over their experiment recoveries. A fully operational RPC System consists of: (1) a carrier spacecraft; (2) a ground control station for communication with customer payloads and the carrier; (3) a ground processing facility to provide refurbishment, final checkout, and integration of customer payloads and the carrier; and (4) the personnel required to support both the development and operation phases of the program. Customer payloads will fly 6 to 18 month missions, or longer, as required. Spreading launch, operations, and retrieval costs over multiple experimental payloads results in minimized customer costs. The RPC Program's initial objective is to operate a simple carrier system which meets basic customer service needs.

Perry, Arthur T.↗

Inflated concepts for the earth science geostationary platform and an associated flight experiment

Large parabolic reflectors and solar concentrators are of great interest for microwave transmission, solar powered rockets, and Earth observations. Collector subsystems have been under slow development for a decade. Inflated paraboloids have a great weight and package volume advantage over mechanically erected systems and, therefore, have been receiving greater attention recently. The objective of this program was to produce a 'conceptual definition of an experiment to assess in-space structural damping characteristics and effects of the space meteoroid environment upon structural integrity and service life of large inflatable structures.' The flight experiment was to have been based upon an inflated solar concentration, but much of that was being done on other programs. To avoid redundancy, the Earth Science Geostationary Platform (ESGP) was selected as a focus mission for the experiment. Three major areas were studied: the ESGP reflector configuration; flight experiment; and meteoroids.

Friese, G.↗

On-orbit assembly operations and in-space infrastructure

The paper describes the development of a set of top-level system requirements for an in-space infrastructure which will accommodate the vehicles proposed for the Space Exploration Initiative (SEI). Issues considered include the current SEI mission strategy, the launch capability, the role of Space Station Freedom (SSF), the on-orbit assembly operations, and the manned tended versus robotic capability. Current SEI mission strategy coupled with SSF planning led to the conclusion that an independent assembly servicing facility (ASF) will best meet the requirements of the SEI program, and an analysis was performed to define the functions required at an ASF. It is shown that the ASF functions can be performed by telerobotic operations.

Cockrell, Charles E.↗

General Public Space Travel and Tourism: Executive Summary - Volume 1

Travel and tourism is one of the world's largest businesses. Its gross revenues exceed $400 billion per year in the U.S. alone, and it is our second largest employer. U.S. private sector business revenues in the space information area now approximate $10 billion per year, and are increasing rapidly. Not so in the human spaceflight area. After spending $100s of billions (1998 dollars) in public funds thereon, and continuing to spend over $5 billion per year, the government is still the only customer for human spaceflight goods and services. Serious and detailed consideration was first given to the possibility of space being opened up to trips by the general public three decades ago, and some initial attempts to do so were made a dozen years ago. But the difficulties were great and the Challenger disaster put an end to them. In recent years professional space tourism studies have been conducted in the United Kingdom, Germany and, especially, Japan. In the U.S., technological progress has been pronounced; we have had nearly a decade's experience in seeing our astronauts travel to-from low Earth orbit (LEO) safely, and we expect to commence assembly of a LEO space station housing a half-dozen people this year. Too, NASA and our space industry now have new and promising space transportation development programs underway, especially the X-33 and X-34 programs, and some related, further generation, basic technology development programs. And five private companies are also working on the design of new surface - LEO vehicles. The first professional space tourism market studies have been conducted in several countries in the past few years, especially in Japan and here. The U.S. study makes it clear that, conceptually, tens of millions of us would like to take a trip to space if we could do so with reasonable safety, comfort and reliability, and at an acceptable price. Initial businesses will address the desires of those willing to pay a greater price and accept a greater risk. A two-year cooperative Space Act agreement study has been conducted by our National Aeronautics and Space Administration and the Space Transportation Association. It was conducted by NASA and STA study leaders drawing upon the competence, experience and hard-nosed imagination of a national Steering Group and scores of attendees at a multi-day Workshop. The study has involved scores of professionals and business people from various areas: astronauts; space booster technology and operations professionals; a hotel architect and a hotel operator; an airline planner; insurance underwriters; space sickness experts; space theme park designers; space and travel and tourism association and business executives; a space-related financier; university tourism and space policy experts; present and former space-responsible government officials; space entrepreneurs; space writers; This study concludes that serious national attention should now be given to activities that would enable the expansion of today's terrestrial space tourism businesses, and the creation of in-space travel and tourism businesses. Indeed, it concludes that, in time, it should become a very important part of our Country's overall commercial and civil space business-program structure.

ONeil, Daniel↗

In-Space Internet-Based Communications for Space Science Platforms Using Commercial Satellite Networks

The continuing technological advances in satellite communications and global networking have resulted in commercial systems that now can potentially provide capabilities for communications with space-based science platforms. This reduces the need for expensive government owned communications infrastructures to support space science missions while simultaneously making available better service to the end users. An interactive, high data rate Internet type connection through commercial space communications networks would enable authorized researchers anywhere to control space-based experiments in near real time and obtain experimental results immediately. A space based communications network architecture consisting of satellite constellations connecting orbiting space science platforms to ground users can be developed to provide this service. The unresolved technical issues presented by this scenario are the subject of research at NASA's Glenn Research Center in Cleveland, Ohio. Assessment of network architectures, identification of required new or improved technologies, and investigation of data communications protocols are being performed through testbed and satellite experiments and laboratory simulations.

Kerczewski, Robert J.↗

Space Resources Development: The Link Between Human Exploration and the Long-Term Commercialization of Space

In a letter to the NASA Administrator, Dan Goldin, in January of 1999, the Office of Management and Budget (OMB) stated the following . OMB recommends that NASA consider commercialization in a broader context than the more focused efforts to date on space station and space shuttle commercialization. We suggest that NASA examine architectures that take advantage of a potentially robust future commercial infrastructure that could dramatically lower the cost of future human exploration." In response to this letter, the NASA Human Exploration and Development of Space (HEDS) Enterprise launched the BEDS Technology & Commercialization Initiative (HTCI) to link technology and system development for human exploration with the commercial development of space to emphasize the "D" (Development) in BEDS. The development of technologies and capabilities to utilize space resources is the first of six primary focus areas in this program. It is clear that Space Resources Development (SRD) is key for both long-term human exploration of our solar system and to the long-term commercialization of space since: a) it provides the technologies, products, and raw materials to support efficient space transportation and in-space construction and manufacturing, and b) it provides the capabilities and infrastructure to allow outpost growth, self-sufficiency, and commercial space service and utility industry activities.

Sanders, Gerald B.↗

The Attached Payload Facility Program: A Family of In-Space Commercial Facilities for Technology, Science and Industry

It is anticipated that as the utilization of space increases in both the government and commercial sec tors the re will be a high degree of interest in materials and coatings research as well as research in space environment definition, deployable structures, multi-functional structures and electronics. The International Space Station (ISS) is an excellent platform for long-term technology development because it provides large areas for external attached payloads, power and data capability, and ready access for experiment exchange and return. An alliance of SPACEHAB, MicroCraft, Inc. and SpaceTec, Inc. has been formed to satisfy this research need through commercial utilization of the capabilities of ISS. The alliance will provide a family of facilities designed to provide low-cost, reliable access to space for experimenters. This service would start as early as 1997 and mature to a fully functional attached facility on ISS by 2001. The alliances facilities are based on early activities by NASA, Langley Research Center (LaRC) to determine the feasibility of a Material Exposure Facility (MEF).

Avery, Don E.↗