Capsulation Satellite: CapSat
This PowerPoint presentation will discuss a new small spacecraft architecture which takes advantage of ESPA Class rideshare opportunities.
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This PowerPoint presentation will discuss a new small spacecraft architecture which takes advantage of ESPA Class rideshare opportunities.
This PowerPoint presentation will discuss a new small spacecraft architecture which takes advantage of ESPA (Evolved Expendable Launch Vehicle (EELV) Secondary Payload Adapter) Class rideshare opportunities.
Significant advances in the capabilities of small spacecraft over the past 20 years, coupled with improved access to space from a variety of launch platforms have created new opportunities for scientific exploration and commercial application using these high-value (and yet low cost) platforms. Continued development and demonstration of key technologies are improving the performance of the 3U and 6U class CubeSats while expanding the small spacecraft reach into larger platforms, such as 12U and ESPA class missions. The availability and relatively low cost of CubeSat spacecraft allows key technologies to be flight qualified, bridging the TRL 6/7 gap and making truly novel and enabling technologies available to much larger missions in the planning stages at NASA. The key is connecting the technologists with the flight opportunity in a time and cost efficient manner. NASA’s Small Satellite Technology (SST) program is using existing commercial spacecraft to provide a common bus for technology demonstration, taking advantage of their proven platforms and system with proven flight heritage and extensive infrastructure. In this paper we discuss the Pathfinder Technology Demonstrator (PTD) series of four spacecraft and the CubeSat Laser Infrared CrosslinK (CLICK) series of three spacecraft, the approach SST took in facilitating the missions, the successes of those missions as well as lessons learned in the process. NASA’s PTD spacecraft series is demonstrating a variety of new technologies on-orbit, providing proof of the maturity of these significant new technologies, and enhancing the performance of future CubeSats. Each of the four PTD mission consists of one 6-unit (6U) CubeSat weighing approximately 12 kilograms and measuring approximately 30 centimeters x 25 centimeters x 10 centimeters, characterizing its payload within 90 days of orbit insertion. The spacecraft bus, integration and test, and mission operations services are being provided by Terran Orbital. The PTD missions have demonstrated a novel nano-spacecraft compatible propulsion systems (enabling deep space and maneuverable Cubeat missions) and an optical communications system (enabling high data rate collection and communications) already. The CLICK missions are demonstrating compact space-to-space optical communications first with the CLICK A technology demonstrator (already flown) and finally with the CLICK BC dual spacecraft mission. Both projects are part of the SST program within the NASA Space Technology Mission Directorate. SST is chartered to develop and demonstrate technologies to enhance and expand the capabilities of small spacecraft with a particular focus on enabling new mission architectures through the use of small spacecraft, expanding the reach of small spacecraft to new destinations, and augmenting future missions with supporting small spacecraft.
We demonstrate that a low-cost spacecraft bus based on the Propulsive ESPA architecture, launched as a directed facility alongside a mission to the outer solar system, enables innovative and viable SIMPLEx-class missions to the outer solar system and achieve high-value science objectives. As a case study, we present a Propulsive ESPA bus that could be launched with the Dragonfly mission toward the Saturn System and carry two small spacecraft weighing up to 130 kg each. We advocate a mission architecture that enables delivering multiple small missions to the Saturn System on a stand-alone Carrier-Relay Spacecraft (CRSC) that flies independently, and poses zero impact on the Dragonfly Mission. To accommodate this architecture, the launch vehicle will require an upgrade from Dragonfly's notional Atlas V 411 to Atlas V 541. Raising the SIMPLEx cost cap from the current $55M, and excluding Phase E costs will also make outer-planet missions viable in the SIMPLEx program. We have identified multiple high-value mission concepts that fit within the 130 kg limit. As examples, we present concepts for Saturn Probe, Saturn Ring In-Situ Explorer, Magnetospheric Explorer, and Enceladus Plume Sampler.
Technology Demonstration Missions (TDM) is in its third year of execution, being initiated in 2010 and baselined in January of 2012. There are 11 projects that NASA Marshall Space Flight Center (MSFC) has contributed to or led: (1) Evolvable Cryogenics (eCryo): Cyrogenic Propellant Storage and Transfer Engineering Development Unit (EDU), a proof of manufacturability effort, used to enhance knowledge and technology related to handling cryogenic propellants, specifically liquid hydrogen. (2) Composites for Exploration Upper Stage (CEUS): Design, build, test, and address flight certification of a large composite shell suitable for the second stage of the Space Launch System (SLS). (3) Deep Space Atomic Clock (DSAC): Spaceflight to demo small, low-mass atomic clock that can provide unprecedented stability for deep space navigation. (4) Green Propellant Infusion Mission (GPIM): Demo of high-performance, green propellant propulsion system suitable for Evolved Expendable Launch Vehicle (EELV) Secondary Payload Adapter (ESPA)-class spacecraft. (5) Human Exploration Telerobotics (HET): Demonstrating how telerobotics, remote control of a variety of robotic systems, can take routine, highly repetitive, dangerous or long-duration tasks out of human hands. (6) Laser Communication Relay Demo (LCRD): Demo to advance optical communications technology toward infusion into deep space and near Earth operational systems, while growing the capabilities of industry sources. (7) Low Density Supersonic Decelerator (LDSD): Demo new supersonic inflatable decelerator and parachute technologies to enable Mars landings of larger payloads with greater precision at a wider range of altitudes. (8) Mars Science Laboratory (MSL) Entry Descent & Landing Instrumentation (MEDLI): Demo of embedded sensors embedded in the MSL heat shield, designed to record the heat and atmospheric pressure experienced during the spacecraft's high-speed, hot entry in the Martian atmosphere. (9) Solar Electric Propulsion (SEP): 50-kW class spacecraft that uses flexible blanket solar arrays for power generation and an electric propulsion system that delivers payload from low-Earth orbit to higher orbits. (10) Solar Sail Demonstration (SSD): Demo to validate sail deployment techniques for solar sails that are propelled by the pressure of sunlight. (11) Terrestrial HIAD Orbit Reentry (THOR): Demo of a 3.7-m Hypersonic Inflatable Aerodynamic Decelerator (HIAD) entry vehicle to test second generation aerothermal performance and modeling.
The Solar Array System contracts awarded by NASA's Space Technology Mission Directorate are developing solar arrays in the 30 kW to 50 kW power range (beginning of life at 1 AU) that have significantly higher specific powers (W/kg) and much smaller stowed volumes than conventional rigid-panel arrays. The successful development of these solar array technologies has the potential to enable new types of solar electric propulsion (SEP) vehicles and missions. This paper describes a 30-kW electric propulsion vehicle built into an EELV Secondary Payload Adapter (ESPA) ring. The system uses an ESPA ring as the primary structure and packages two 15-kW Megaflex solar array wings, two 14-kW Hall thrusters, a hydrazine Reaction Control Subsystem (RCS), 220 kg of xenon, 26 kg of hydrazine, and an avionics module that contains all of the rest of the spacecraft bus functions and the instrument suite. Direct-drive is used to maximize the propulsion subsystem efficiency and minimize the resulting waste heat and required radiator area. This is critical for packaging a high-power spacecraft into a very small volume. The fully-margined system dry mass would be approximately 1120 kg. This is not a small dry mass for a Discovery-class spacecraft, for example, the Dawn spacecraft dry mass was only about 750 kg. But the Dawn electric propulsion subsystem could process a maximum input power of 2.5 kW, and this spacecraft would process 28 kW, an increase of more than a factor of ten. With direct-drive the specific impulse would be limited to about 2,000 s assuming a nominal solar array output voltage of 300 V. The resulting spacecraft would have a beginning of life acceleration that is more than an order of magnitude greater than the Dawn spacecraft. Since the spacecraft would be built into an ESPA ring it could be launched as a secondary payload to a geosynchronous transfer orbit significantly reducing the launch costs for a planetary spacecraft. The SEP system would perform the escape from Earth and then the heliocentric transfer to the science target.
Selected by NASA as an ESPA-class rideshare technology demonstration mission to launch with the Interstellar Mapping and Acceleration Probe (IMAP) mission in 2025, the NASA MSFC Solar Cruiser mission will mature solar sail technology for use in future Heliophysics missions, as well as missions of interest across a broad user community including NOAA, Earth, and Planetary Sciences. Solar sails, which use reflected sunlight to derive thrust, can be used to create artificial equilibria and near-indefinite station-keeping at locations sunward of L1 along the Sun Earth Line (SEL), or at any desired offset from the SEL leading or trailing the Earth in its orbit. They can change the heliocentric inclination of a spacecraft from the ecliptic to as high as solar polar, stopping and remaining at any intermediate inclination orbit in between or can be used around a range of solar system bodies. The Solar Cruiser mission will fly a small spacecraft (~100 kg) with a large (>1600 square meter) solar sail containing embedded reflectivity control devices (RCDs) and photovoltaic cells, attaining a characteristic acceleration of >0.12 mm/s2. The mission concept includes successful deployment of the solar sail, validation of all sail subsystems, controlled station-keeping inside of the Sun-Earth L1 point, demonstration of pointing performance for science imaging, and finally an increase in heliocentric inclination (out of the ecliptic plane). Solar Cruiser would serve as a pathfinder for missions that observe the solar environment from unique vantage points such as a high inclination solar mission, opening a fundamentally new range of observational capabilities for the Heliophysics Program and for space weather monitoring. Observations away from the Sun-Earth line (SEL) present unique opportunities for answering the outstanding science questions of Heliophysics, for improving space-weather monitoring and prediction, and for revealing new discoveries about our Sun and solar system. High solar inclinations are particularly compelling. Investment in, and demonstration of, the technology needed to enable polar missions is essential to making this unique vantage point a reality in the next decade.
State of the art deployable structures are mainly being designed for medium to large size satellites. The lack of reliable deployable structural systems for low cost, small volume, rideshare-class spacecraft severely constrains the potential for using small satellite platforms for affordable deep space science and exploration precursor missions that could be realized with solar sails. There is thus a need for reliable, lightweight, high packaging efficiency deployable booms that can serve as the supporting structure for a wide range of small satellite systems including solar sails for propulsion. The National Air and Space Administration (NASA) is currently investing in the development of a new class of advanced deployable shell-based composite booms to support future deep space small satellite missions using solar sails. The concepts are being designed to: meet the unique requirements of small satellites, maximize ground testability, permit the use of low-cost manufacturing processes that will benefit scalability, be scalable for use as elements of hierarchical structures (e.g. trusses), allow long duration storage, have high deployment reliability, and have controlled deployment behavior and predictable deployed dynamics. This paper will present the various rollable boom concepts that are being developed for 5-20 m class size deployable structures that include solar sails with the so-called High Strain Composites (HSC) materials. The deployable composite booms to be presented are being developed to expand the portfolio of available rollable booms for small satellites and maximize their length for a given packaged volume. Given that solar sails are a great example of volume and mass optimization, the booms were designed to comply with nominal solar sail system requirements for 6U CubeSats, which are a good compromise between those of smaller form factors (1U, 2U and 3U CubeSats) and larger ones (12 U and 27 U future CubeSats, and ESPA-class microsatellites). Solar sail missions for such composite boom systems are already under consideration and development at NASA, as well as mission studies that will benefit from planned scaled-up versions of the composite boom technologies to be introduced. The paper presents ongoing research and development of thin-shell rollable composite booms designed under the particular stringent and challenging system requirements of relatively large solar sails housed on small satellites. These requirements will be derived and listed. Several new boom concepts are proposed and other existing ones are improved upon using thin-ply composite materials to yield unprecedented compact deployable structures. Some of these booms are shown in Fig. 1. For every boom to be introduced the scalable fabrication process developed to keep the overall boom system cost down will be shown. Finally, the initial results of purposely designed boom structural characterization test methods with gravity off-loading will be presented to compare their structural performance under expected and general load cases.