SmallSat Standardized Architecture

SmallSat designers seek to employ restraints and release mechanisms of minimal size and weight, often placing each on the outside of the SmallSat structure. Surprisingly, "fishing line" (released via burn through) is often used to secure and release deployables. Vibrations and forces generated during launch can stretch the fishing line, thus allowing these precious deployables to become damaged or otherwise not release properly later on. While these small sats are less expensive than their larger counterparts, satellite owners must minimize the chance that deployables are damaged or that deployment is unsuccessful. Five years ago, engineers at NASA GSFC faced these SmallSat deployment challenges and knew a better way must exist to prevent equipment damage and ensure successful release. Investigating a host of designs to minimize size, weight, and cost while maximizing communication and mechanical reliability, NASA's engineers created DANY (the Diminutive Assembly for Nanosatellite deploYables). NASA's DANY technology uses spring-loaded metal pins, a reliable burn-through mechanism, efficient bracketing, and a circuit board - all within a 3.0" x 1.3" x 0.2" volume (smaller than a stack of 10 business cards) - to reliably stow and release deployables on command. Using DANY, stowed deployables are securely fastened using the spring-loaded locking pins. Upon receiving a deployment signal, a plastic restraining link is burned through which allows the spring-loaded pins to release the deployable and simultaneously trigger a switch to signal a successful deployment event.

The innovation is a miniaturized memory board that will have up to 96 GB of NAND Flash memory along with either a radiation tolerant FPGA or a set of three commercial FPGAs. The memory board is designed to interface with the standard subsystems of Goddards Modular SmallSat Architecture (GMSA). While previous memory cards are larger, this one is designed to fit within a 1U form factor.

NASA's newly developed antenna is lightweight (at or below 2 grams), low volume (at or below 1.2 cm3), and low stowage thickness (approx. 0.7 mm), all while delivering high performance (at or above 10 dBi gain). The antenna includes a novel design-material combination in a helical coil conformation. The design allows the antenna to compress for stowage (e.g., satellite launch), then self-deploy at the desired time in orbit. NASA's lightweight, self-deployable helical antenna can be integrated into a thin-film solar array (or other large deployable structures). Integrating antenna elements into deployable structures such as power generation arrays allows spacecraft designers to maximize the inherently limited resources (e.g., mass, volume, surface area) available in a small spacecraft. When used as a standalone (i.e., single antenna) setup, the the invention offers moderate advantages in terms of stowage thickness, volume, and mass. However, in applications that require antenna arrays, these advantages become multiplicative, resulting in the system offering the same or higher data rate performance while possessing a significantly reduced form factor. Prototypes of NASA's self-deployable, helical antenna have been fabricated in S-band, X-band, and Ka-band, all of which exhibited high performance. The antenna may find application in SmallSat communications (in deep space and LEO), as well as cases where low mass and stowage volume are valued and high antenna gain is required.

A NASA team gave itself just one year to develop, test and integrate a CubeSat that could reliably and easily accommodate agency-class science investigations and technology demonstrations at a lower cost. The CubeSat known as Dellingr, a name derived from the god of the dawn in Norse mythology will carry three heliophysics-related payloads. It doubles the payload capability of the ubiquitous and proven three-unit, or 3U, CubeSat pioneered by the California Polytechnic Institute in 1999 primarily for the university community. The need for such a platform, which measures about 12 inches long, nearly 8 inches wide and 4 inches high, was for more cost-effective approaches to achieve compelling Earth and space science. Disadvantages of the 3U size include more constraints on volume and power. Furthermore, some studies suggest that previous CubeSats failed 40 percent of the time. By doubling the platform's girth, increasing its power capacity, and employing novel processes to increase its on-orbit reliability, the team believes it will have created a platform capable of carrying out more robust missions for science. Once successfully demonstrated, the team says it will make the platform's design implemented with low-cost, commercial off-the-shelf parts available to any U.S. organization interested in using it.

The goal of COTSAT as a technology demonstration unit is to demonstrate the ability for drastic cost reduction in spacecraft design and to develop methods and technologies for maximizing reuse of developed spacecraft hardware, software and related technology on future missions. This approach will enable for rapid response capabilities given advances in rapid prototyping. COTSAT consists of the following sub-systems: - An artificial environment container, which comprises much of the satellite structure, is used to contain the single atmosphere environment. The artificial atmosphere container is used to replicate an Earth-like atmosphere, allowing the use of Commercial-Off-The Shelf (COTS) hardware and electronics which were not necessarily originally designed to operate in the vacuum environment of space. - A key design element in the bus structure of COTSAT is the modular platform upon which the bus is assembled. This structure allows for a logic-flow integration of components leading to ideal placement of electronics. - The Electrical Power System (EPS) architecture utilizes a distributed power and self-monitor approach. - The Command and Data Handling (C&DH) subsystem provides a number of critical capabilities, including spacecraft health and status monitoring, communication, payload science data management and subsystem management. - The COTSAT communications architecture incorporates four independent communications paths. - The software architecture consists of modular, independent software daemons for each subsystem or capability such as the star tracker, the Inertial Measurement Unit (IMU), the reaction wheels, the main executive, the communications system, the control system and the payload. - The COTSAT has a three-axis Attitude Determination And Control System (ADACS), using four reaction wheels and three magnetic torque coils. - To aid in technology development and testing, the COTSAT hardware and technology performance has been verified by a number of prototype test-beds. There have been three major test platforms during the development cycle.