The Space Technology Research Vehicle (STRV)-1 program, initiated by the UK Ministry of Defence and the US Ballistic Missile Defense Organization under terms of an agreement originally signed by President Reagan and Prime Minister Thatcher, has resulted in new opportunities for researchers to acquire low-cost on-orbit data. The STRV-1 a/b satellites were launched into a geotransfer orbit (GTO) on June 1994, and continued operation until the mission was terminated in September, 1998. Data returned from the on-board experiments has provided new insights into the nature of the terrestrial radiation belts and the effects of this radiation on critical spacecraft materials and components. The flexibility of the on-board computer also enabled successful demonstration of new space communication protocol standards. Transfer of day-to-day satellite operations from the Defence Evaluation and Research Agency to the University of Colorado clearly showed that spacecraft conforming to CCSDS standard protocols can be rapidly cross- supported across an international boundary. The next satellites in the STRV-1 program, STRV-1 c/d, will carry 21 hardware experiments sponsored by the US, UK, Canada, and ESA, and will provide on-board computing capability for conducting three software experiments. Launch into GTO in the latter part of 2000 will result in exposure of all satellite systems and experiments to increasing solar activity and its resulting influence on Van Allen belt radiation fluence.
Small satellite programs offer opportunities for conducting technical demonstrations, engineering development and scientific missions. To accomplish these missions, launch systems are needed whose costs and capacity are commensurate with the use of small, low-cost satellites. Lower launch costs would open the door to more technology demonstrations and scientific missions that will drive the need for more launch vehicle. There are several new ventures that could increase the opportunity for small payloads to achieve economical access to space. These new ventures include low cost launch vehicles, standard adapters, orbit transfer vehicles, and space maneuver vehicles. The National Reconnaissance Office's (NRO) Broad Agency Announcement (BAA) includes competitive selection for proposals to study the need for a small payload broker, to define the broker's services, and innovative ideas to simplify the process of integrating payloads, spacecraft buses, and launch vehicles. The NRO and Goddard Spaceflight Center (GSFC) combined resources to develop the Access to Space (ATS) web site that contains both a mission database and launch vehicle information. It provides both the information and the tools necessary to assist mission planners in selecting and planning their ride to space. Users can search the site for available rides and also post information about their payloads. Launch providers can submit information about planned missions and launch vehicle configuration.
Despite growing international interest in small satellites, high dedicated expendable launch vehicle costs and the lack of secondary launch opportunities continue to hinder the full exploitation of small satellite technology. In the United States, the Department of Defense (DoD), NASA, other government agencies, commercial companies, and many universities use small satellites to perform space experiments, demonstrate new technology, and test operational prototype hardware. In addition, the DoD continues to study the role of small satellites in fulfilling operational mission requirements. However, the US lacks sufficient small satellite launch capacity. Furthermore, US government agencies are restricted to the use of US launch vehicles, which eliminates many affordable launch opportunities. In an effort to increase the number of space experiments that can be flown with a small, fixed budget, the DoD Space Test Program (STP) has teamed with the Air Force Research Laboratory Space Vehicles Directorate (AFRL/VS) to develop a low-cost solution for the small satellite launch program. Our solution, which can be implemented on both Boeing and Lockheed-Martin Evolved Expendable Launch Vehicle-Medium (EELV-M) boosters, is called the EELV Secondary Payload Adaptor (ESPA). ESPA will increase the number of launch opportunities for 180kg-class (or smaller) satellites at prices highly competitive with other secondary launch services worldwide.
The STRV-2 program is the second in a series of three collaborative flight test programs between the U.S. Ballistic Missile Defense Organization (BMDO) and the United Kingdom (UK) Minstry of Defence (MoD). The STRV-2 Experiment Module contains five major experiments to provide proof-of-concept data on system design, data on the mid-earth orbit (MEO) space environment, and data on durability of materials and components operating in the MEO environment. The UK Defence Evaluation and Research Agency (DERA) has provided a mid- wavelength infrared (MWIF) imager to evaluate passive detection of aircraft from space. BMDO, in conjunction with the US Air Force Research Laboratory (AFRL) and the National Aeronautics and Space Administration (NASA), have provided experiments to evaluate use of adaptive structures for vibration suppression, to investigate the use of high bandwidth laser communications to transmit data from space to ground or airborne receivers, to study the durability of materials and components in the MEO space environment, and to measure radiation and micrometeoroid/debris fluence. These experiments are mounted on all- composite structure. This structure provides a significant reduction in weight and cost over comparable aluminum designs while maintaining the high stiffness required by optical payloads. In 1994, STRV-2 was manifested for launch by the DOD Space Test Program. STRV-2, the primary payload on the Tri-Service eXperiment (TSX)-5 spacecraft, was successfully launched on 7 June 2000 on a Pegasus XL from Vandenbery AFB, CA. The STRV-2 program, like the companion STRV-1 program, validates the viability of multi-national, multi-agency collaborations to provide cost effective acquisition of space test data. The experimental data to be obtained will reduce future satellite risk and provide guidelines for further system development.
A primary goal of the Defense Advanced Research Projects Agency is to develop innovative, high-risk technologies with the potential of a revolutionary impact on missions of the Department of Defense. DARPA is developing a space experiment to prove the feasibility of autonomous on- orbit servicing of spacecraft. The Orbital Express program will demonstrate autonomous on-orbit refueling, as well as autonomous delivery of a small payload representing an avionics upgrade package. The maneuverability provided to spacecraft from a ready refueling infrastructure will enable radical new capabilities for the military, civil and commercial spacecraft. Module replacement has the potential to extend bus lifetimes, and to upgrade the performance of key subsystems (e.g. processors) at the pace of technology development. The Orbital Express technology development effort will include the necessary autonomy for a viable servicing infrastructure; a universal interface for docking, refueling and module transfers; and a spacecraft bus design compatible with this servicing concept. The servicer spacecraft of the future may be able to act as a host platform for microsatellites, extending their capabilities while reducing risk. An infrastructure based on Orbital Express also benefits from, and stimulates the development of, lower-cost launch strategies.
The Access To Space (ATS) Group at NASA's Goddard Space Flight Center (GSFC) supports the science and technology community by facilitating frequent and affordable opportunities for access to space. The ATS Group has developed an interactive Mission Design web site that provides both the information and the tools necessary to assist mission planners in selecting and planning their ride to space. The ATS web site was developed through core partnerships with other government agencies seeking similar tools for their mission planners. Key design features of the site include a searchable mission database and launch vehicle toolboxes. The mission database contains a listing of missions ranging from proposed missions to manifested missions allowing users to interactively search for potential partnering opportunities. Missions can be added to the database by the user community through data input tools. The launch vehicle toolbox section provides the user with a full range of information on vehicle classes and individual configurations. This section has been enhanced to include additional access modes such as RLVs, ultra long duration balloons, sub-orbital rockets, Space Shuttle carriers, and spacecraft buses. Use of the ATS web site has climbed 400$ in the last six months indicating widespread usage across the mission planning community.
During the 1960's, as the importance of the space environment was recognized, it became apparent that space systems technologies needed to be developed at a rapid rate. The Department of Defense (DoD) realized that before developing and deploying space systems for operational use, the needed to be tested in space. At that time no organization of funds were readily available to provide timely spaceflight for military space systems. As a result, the DoD Space Test Program (STP) was created in 1966 by a memorandum from the Director of Defense Research and Engineering (DDR&E). The purpose of this program was to provide flight opportunities for all DoD research and development activities in an economic and efficient manner. For a payload to be flown by STP it must first be sponsored by a DoD organization. The payload is then briefed through a series of service review boards until it reaches the DoD level. The DoD Space Experiment Review Board (SERB) makes the final selections and gives STP a ranked list of payloads to attempt to fly. This process happens annually, and STP flies as many payloads as funding and opportunity allow.
The purpose of the CubeSat development is to define a standard bus that can be used by anyone needing a simple picosatellite. Defining a standard bus, developing standard hardware components using commercial off the shelf components and a standard spacecraft frame will simplify the development of picosatellites. The CubeSat development will provide a standard spacecraft frame, a spacecraft controller, radio transceiver, attitude determination and control, solar cells, batteries, and an interface for a payload. The developer needs only to concentrate on the payload.
Cal Poly students are participating in the development of a new class of picosatellite, the CubeSat. CubeSats are ideal as a development project for universities around the world. In additioin to their significant role in educating space scientists and engineers, CubeSats provide a low-cost platform for testing and space qualification of the next generation of small payloads in space. In expensive, commercial off-the- shelf components are used to demonstrate their ability to function in the space environment. A key innovation of the project is the development of a standard CubeSat deployer. This deployment system is capable of releasing a number of CubeSats as secondary payloads on a wide range of launchers. The standard deployer requires all CubeSats to conform to common physical requirements, and share a standard interface with the deployer.
Proc. SPIE 4136, Space system developments at Stanford University: from launch experience of microsatellites to the proposed future use of picosatellites, 0000 (7 November 2000); doi: 10.1117/12.406646
The Space Systems Development Laboratory was established in 1994 at Stanford University to give graduate and undergraduate students project based learning experience in microsatellite design, fabrication, test, launch integration and space operations. These students have completed two satellites - one called OPAL was launched on January 26, 2000, and the second called SAPPHIRE is tentatively scheduled for launch in late 2002. There are three additional satellites now in developments. OPAL had a unique primary objective payload. This was to launch six small Klondike ice cream bar size picosatellites. It completed this mission to gain a record of orbiting the world's smallest functional satellites. The next generation in picosats under developement that have a tentative late 2002 launch are called CubeSats. Launchers are under development to release multiple 4-inch cube CubeSats that can be used by amateur radio enthusiast, universities and government laboratories for inexpensive space testing.
Imagine that information processing human-machine network is threatened in a particular part of the world. Suppose that an anticipated threat of physical attacks could lead to disruption of telecommunications network management infrastructure and access capabilities for small geographically distributed groups engaged in collaborative operations. Suppose that small group of astronauts are exploring the solar planet and need to quickly configure orbital information network to support their collaborative work and local communications. The critical need in both scenarios would be a set of low-cost means of small team celestial networking. To the geographically distributed mobile collaborating groups such means would allow to maintain collaborative multipoint work, set up orbital local area network, and provide orbital intranet communications. This would be accomplished by dynamically assembling the network enabling infrastructure of the small satellite based router, satellite based Codec, and set of satellite based intelligent management agents. Cooperating single function pico satellites, acting as agents and personal switching devices together would represent self-organizing intelligent orbital network of cooperating mobile management nodes. Cooperative behavior of the pico satellite based agents would be achieved by comprising a small orbital artificial neural network capable of learning and restructing the networking resources in response to the anticipated threat.
Miniaturization and reduction of design and production costs of electronics is at the forefront of today's technological efforts. Ground based applications have been the forerunner of this trend. It is proposed that a space analog be created. A modular architectural approach to the construction of an extremely small satellite may provide a standard for future space-based research, educational, and communication platforms. Dartsat is to meet such specifications while providing the footing for ongoing research ons pace operations at Dartmouth College. The first iteration of Dartsat is to serve as a model for future missions. Dartsat has dimensions of ten centimeters cubed; the maximum allowable mass is one kilogram. Of this volume, roughly 75 cm3 is occupied by mechanical superstructure. The remainder of the volume, approximately 925 cm3, is divided into modular bays. The control, power, and radio communication (CPR) of the satellite occupies one of these bays. The other bays are to be outfitted with standardized interfaces allowing the snap-in of interchangable, independently engineered payloads. The unique design of Dartsat is to provide a benchmark for future space flight orbital operations.
In recent years there has been a significant increase in demand for testing, qualification and evaluation of satellite components in space. This will continue to be true with the dramatic growth in remote sensing and communication satellites and constellations. Finding ways to space qualify components and sensors without paying for expensive, dedicated space experiments has prompted a number of aerospace companies (large and small) and government organizations to increase their emphasis on providing low-cost access to space by means of secondary rides on primary payloads and launch vehicle structures. Proactive rideshare brokering is a process that supports space testing by actively providing the information, processes and equipment necessary to support successful space testing. As U.S. space programs have grown in scope and cost, the capacity to accetp risk as part of the development process has diminished - resulting in reduced levels of innovation and erosion of our space industry domination. In contrast, the international space community has instituted a number of innovative processes that support low cost entry to space for small programs. This has stimulated new space systems industries in many countries around the world. This growth is closely coupled with the dynamic growth in the International space launch industry. Proactive rideshare brokering takes a new approach to secondary payload integration. Many commercial and government payload integration services have taken the approach "If you build it they will come." This is not sufficiently aggressive to attract the new technologists who know very little about space testing. Proactive brokering must take a "You must go out and actively seek high-payoff technology payloads" approach to have a true impact on the implementation of new space system technologies. It should also include the application of proven practices from the international payload integration community. The paper draws conclusions by comparing what has been done historically and currently in the international space payload integration community versus what the current practices are in the U.S.. Observations and recommendations are made that reflect a reduced timeline approach and that acknowledge the close coupling between the technology base, the space systems industry, infrastructure and educational processes.
There appears to be exponential growth in the number of micro-satellites being built, but because of the high cost of launch services, few of these micro-satellites are being launched. The only practical avenue open to get these smaller payloads launched is as secondary payloads. As is often the case with hitchhikers, they have a desired destination, but are usually dropped off short of that destination. SpaceDev is developing a family of small and inexpensive micro-kick motors, with a varying degree of capabilities, to help facilitate these small payloads getting to a satisfactory destination. The technology used is safe, simple and scalable.
A significant part of the burgeoning commercial space industry is placing an unprecedented number of satellites into low earth orbit for a variety of new applications and services. By some estimates the commercial space industry now exceeds that of government space activities. Yet the two markets remain largely separate, with each deploying dedicated satellites and infrastructure for their respective missions. One commercial space firm, Final Analysis, has created a new program wherein either government, scientific or new technology payloads can be integrated on a commercial spacecraft on commercial satellites for a variety of mission scenarios at a fraction of the cost of a dedicated mission. NASA has recognized the advantage of this approach, and has awarded the Quick Ride program to provide frequent, low cost flight opportunities for small independent payloads aboard the Final Analysis constellation, and investigators are rapidly developing science programs that conform to the proposed payload accommodations envelope. Missions that were not feasible using dedicated launches are now receiving approval under the lower cost Quick Ride approach. Final Analysis has dedicated ten out of its thirty-eight satellites in support of the Quick Ride efforts. The benefit of this type of space access extend beyond NASA science programs. Commercial space firms can now gain valuable flight heritage for new technology and satellite product offerings. Further, emerging international space programs can now place a payload in orbit enabling the country to allocate its resources against the payload and mission requirements rather htan increased launch costs of a dedicated spacecraft. Finally, the low cost nature provides University-based research educational opportunities previously out of the reach of most space-related budgets. This paper will describe the motivation, benefits, technical features, and program costs of the Final Analysis secondary payload program. Payloads can be accommodated on up to thirty-eight separate satellites. Since the secondary payloads will fly on satellites designed for global wireless data services, each user can utilize low cost communication system already in place for sending and retrieving digital information from its payload.
CUBESAT is part of an educational outreach to middle and high school students to interest them in science and technology careers by engaging them in achievable space oriented projects. Professor Robert Twiggs of Stanford University has challenged several amateur radio groups to design, build and operate CUBESAT picosatellites with the involvement of schools in their communities. This paper is a progress report of one of the groups, the South Bay Amateur Radio Association, which has accepted this challenge.