Arc Second Pointing System of Near Space Observatories WASP

The Wallops Arc Second Pointer (WASP), developed by the National Aeronautics and Space Administration (NASA) in response to the challenge of sub-arcsecond-level pointing stability for high-altitude scientific balloon platforms during long-duration observational missions, is a near-space observatory-grade sub-arcsecond pointing system designed to establish a multi-payload-compatible near-space astronomical observation platform. Comprising a Pointing Control System (PCS) and a star tracker subsystem (Camera Attitude Reference Determination System, CARDS), WASP serves as the core technology for achieving high-precision fine-pointing control in near-space environments. By integrating precision mechanical and electronic components with super-pressure balloon technology, the system enables extended-duration missions in near-space while maintaining sub-arcsecond-level pointing accuracy. Its modular design and standardized interfaces allow seamless adaptation to diverse scientific payloads, fulfilling varied mission requirements. To transition early-stage ground-test hardware and software from laboratory settings to real-world flight conditions, the WASP team collaborated with multiple research groups to conduct five successive test flights. These flights validated the system's technical methodologies and performance capabilities while enabling further optimizations based on operational mission requirements. Following the completion of WASP’s development phase, the system has engaged in scientific collaborations with numerous research teams, producing notable achievements. Since 2014, WASP has supported missions including the X-Calibur hard X-ray polarimeter, BITSE (Balloon-borne Investigation of Temperature and Speed of Electrons in the corona), PICTURE-C (Planetary Imaging Concept Testbed Using a Recoverable Experiment-Coronagraph), SuperHERO (Super High-Energy Resolution Observatory), and XL-Calibur, yielding groundbreaking scientific results across astrophysics and planetary science domains. In the field of space science, WASP not only expands the research scope of high-altitude balloon platforms but also provides innovative solutions for constructing near-space observatories, advancing the exploration of near-space environments. The successful test flights and operational deployments of WASP have laid a foundation for its applications in planetary science, astrophysics, and Earth observation, while offering a reliable reference for the development of near-space science in China.