A Foldable, Compact and Lightweight Solar Array Substrate with Large Deployed Wingspan for Small Spacecraft

A solar array (SA) mechanical subsystem made of thin and lightweight substrates was developed, built and tested for a small spacecraft. The SA is compactly foldable and deployable to a length of approximately five times the widthof the spacecraft. It has miniature hinges and latches, and deploys freely without dampers and synchronizing mechanisms. The solar cell interconnect harness consists ofthin, laminatedflexible circuits,and the substrates feature a syntactic foam core exposed to large temperature extremes. This developmental technology, currently at TRL 6, when completely proven out, would be viable for small satellites and would enable missions in the Express-class. The Express-class (or Express) refers to satellites in the range of 25kg to 100 kg that are positioned in the gap between 12U CubeSats and small ESPA-class spacecraft. Cornerstones of the SA development were compact packaging, deployment dynamic simulation, and hinge-latch tuning for dynamics and lock-up loads. Dynamic deployment simulations were modeled in Adams to observe the behavior of the unfolding array, to size the hinge springs and to monitor the lockup loads at the substrate to hinge interfaces. Extensive substrate mechanical and thermal tests were conducted to verify the substrate’s structural capability and dimensional stability in its operating environment. Thermal tests were carried out to observe the effect of mismatching coefficients of thermal expansion between the adhered flexible laminated interconnect circuits and the substrate. Gravity-negated wing deployment tests were performed at temperature limits and in vacuum to verify the overall design intent of the deployment. The stowed wing was vibration tested to verify its structural capabilities under launch environments, and then deployment tested again to demonstrate that the array as a mechanism was unaffected by launch loads. Mechanically, the Express SA substrate assembly has been advanced in its development and proven out as a structure and mechanism. Further development of the electrical power system is necessary, and additional testing for mechanical and thermal interactions of the solar cells with the overall SA substrate will need to be done. This SA subsystem would be an essential expansion to the Express hardware developed by The Applied Physics Laboratory (APL) for the advancement and enablement of Express-class missions

Neptune Odyssey: A Flagship Concept for the Exploration of the Neptune–Triton System

The Neptune Odyssey mission concept is a Flagship-class orbiter and atmospheric probe to the Neptune-Triton system. This bold mission of exploration would orbit an ice-giant planet to study the planet, its rings, small satellites, space environment, and the planet-sized moon Triton. Triton is a captured dwarf planet from the Kuiper Belt, twin of Pluto, and likely ocean world. Odyssey addresses Neptune system-level science, with equal priorities placed on Neptune, its rings, moons, space environment, and Triton. Between Uranus and Neptune, the latter is unique in providing simultaneous access to both an ice giant and a Kuiper Belt dwarf planet. The spacecraft - in a class equivalent to the NASA/ESA/ASI Cassini spacecraft - would launch by 2031 on a Space Launch System or equivalent launch vehicle and utilize a Jupiter gravity assist for a 12 yr cruise to Neptune and a 4 yr prime orbital mission; alternatively a launch after 2031 would have a 16 yr direct-to-Neptune cruise phase. Our solution provides annual launch opportunities and allows for an easy upgrade to the shorter (12 yr) cruise. Odyssey would orbit Neptune retrograde (prograde with respect to Triton), using the moon's gravity to shape the orbital tour and allow coverage of Triton, Neptune, and the space environment. The atmospheric entry probe would descend in ~37 minutes to the 10 bar pressure level in Neptune's atmosphere just before Odyssey's orbit-insertion engine burn. Odyssey's mission would end by conducting a Cassini-like "Grand Finale,"passing inside the rings and ultimately taking a final great plunge into Neptune's atmosphere

A Flexible Rideshare Adapter System to Increase Space Access for “Express” Class 20-50 kg Small Satellite Missions

Advances over the past decade in highly reliable commercial electronics, miniaturization techniques, and materials have enabled progressively smaller satellites to provide important scientific and military capability. Access to space, however, continues to be one of the greatest barriers to executing low-cost missions. Capitalizing on significant, otherwise unused launch vehicle (LV) volume and lift mass capability, many developers now seek accommodation as either a secondary payload with some measure of mission/orbit influence (and corresponding cost contribution), or more typically as truly “opportunistic” piggyback/tertiary rideshares. Among the recent leaders in this endeavor are CubeSats, the system class canonically defined as single unit (1U) spacecraft, with typical configurations being developed by many organizations today aggregating three or even six “U” to afford greater mass/volume provision for components. Another popular small satellite class being launched in secondary manifest configurations is the EELV Secondary Payload Adapter (ESPA). Through launches of these rideshare payloads, confidence has been established that they could be safely and readily incorporated into the LV and mission plan without impact to the primary payload. Catalyzed by these successes in dramatically lowering the cost and programmatic barriers to space access, there is growing global interest to find further ways to increase small satellite launch accommodation to quantities well in excess of 10 free-flyer deployments to further leverage unused capacity, support multiple mission partners, and enable the population of constellations. In reflection of this challenge, in early 2011 JHU/APL initiated an internal assessment and investigation of prevailing market solutions for manifesting small satellites as either primary, secondary, or tertiary payloads on a broad variety of current and near-term launch vehicle solutions. Through a combination of top-down analysis and bottoms-up design activities, it was determined that there was a fundamentally un-served niche between 3-6U CubeSats and ESPA-class small satellites, the “Express” mission class, that corresponds to a space vehicle of approximately 20-50 kg and a stowed size of 88,000 cm3. To address these requirements, JHU/APL has developed and built a unique flexible adapter system that can readily integrate with multiple LVs in numerous configurations. While accessing the same low-cost rideshare paradigm as CubeSats, the Express mission class affords far greater utilization of COTS components for reduced program development cost/risk, makes possible the capability for dramatically more system resources (e.g., power generation), and if required, enables integration of propulsion solutions for true orbit flexibility without over-compromising payload SWaP allocation. In this paper we will expand upon analysis findings, associated requirements, expected space vehicle provisions, technical details of the adapter system design, prototype hardware development, and results from qualification testing

ISET ORS Bus Standards and Prototype

Advancing sound and accepted spacecraft bus standards is the objective of the Office of the Secretary of Defense’s (OSD) Operationally Responsive Space (ORS) Bus Standards Initiative. This effort involves multiple government, industry, and academia participants assembled into an Integrated System Engineering Team (ISET). The core ISET industry team members include AeroAstro, Boeing, Design Net Engineering, General Dynamics Spectrum Astro, Loral, Microcosm, MicroSat, Orbital, Raytheon, and Swales. Government and Laboratory team members include the Naval Research Laboratory (NRL), The Johns Hopkins University Applied Physics Laboratory (JHU/APL), Air Force Space and Missile Command (AF SMC), Air Force Research Laboratory (AFRL), MIT/Lincoln Laboratories (MIT/LL), Army Space and Missile Defense Command (SMDC), and Space Dynamics Lab. The ISET generates standards for ORS spacecraft and uses them to build a prototype in order to evaluate and mature the standards. The ISET recently made the second major release of the bus standards documents that are available at the 21st AIAA/USU Conference on Small Satellites. This ISET team is also complemented by an open membership Business Team who provides business case factors for consideration in the standards definition, as well as for input for the acquisition transition plan. This paper describes the status of the ORS Bus Standards developed by the ISET to date including the implementation for the prototype build