SPHERES flight operations testing and execution

Abstract

SPHERES (Synchronized Position Hold Engage Reorient Experimental Satellites) is a formation flight testing facility consisting of three satellites operating inside the International Space Station (ISS).The goal is to use the long term microgravity environment of the ISS to mature formation flight and docking algorithms. The operations processes of SPHERES have also matured over the course of the first seven test sessions. This paper describes the evolution of the SPHERES program operations processes from conception to implementation to refinement through flight experience. Modifications to the operations processes were based on experience and feedback from Marshall Space Flight Center Payload Operations Center, USAF Space Test Program office at Johnson Space Center, and the crew of Expedition 13 (first to operate SPHERES on station). Important lessons learned were on aspects such as test session frequency, determination of session success, and contingency operations. The paper describes the tests sessions; then it details the lessons learned, the change in processes, and the impact on the outcome of later test sessions. SPHERES had very successful initial test sessions which allowed for modification and tailoring of the operations processes to streamline the code delivery and to tailor responses based on flight experiences.

Relative Computer Vision-Based Navigation for Small Inspection Spacecraft

“…To characterize the accuracy (i.e., the systematic bias relative to the true value) and precision (i.e., the measurement repeatability) of the output of the navigation system, the algorithm was implemented on the SPHERES test bed [4] and Low Impact Inspection Vehicle (LIIVe) Goggles [1,5]. These satellites performed a number of relative maneuvers that were measured by the vision system.…”

Cooperative control of modular space robots

“…Thruster redundancy allows the addition of plume impingement constraints to prevent the use of such thrusters. The concept of reconfigurable space systems using simple modules has been proposed for some time, and simple systems have been developed and flown Mohan et al 2009). These systems have the potential to be less expensive and more responsive, adaptable, and robust to the failure of one of its parts than conventional satellites.…”

Robotics and AI-Enabled On-Orbit Operations With Future Generation of Small Satellites

“…Another nanosat-class platform that has been flown in the pressurized microgravity environment within the ISS, and is still active, is SPHERES [22] developed at the Massachusetts Institute of Technology (MIT, Cambridge, MA, USA). The SPHERES facility comprises three identical satellites that are equipped with onboard navigation systems.…”

“…Over the last two decades, important in-space demonstrations using smallsats have been performed to evaluate the maturity of these underpinning technologies. As the first smallsat inspector, the Autonomous Extravehicular Activity Robotic Camera Sprint (AERCam Sprint) [16] played a pivotal role in the development of other small platforms such as the Synchronized Position Hold Engage Reorient Experimental Satellites (SPHERES) [22] and Astrobee [23], [24]. In 1997, the Japanese Engineering Test Satellite VII (ETS-VII) was used to conduct autonomous and teleoperated robotics research into rendezvous and docking, and in-space manipulation with a cooperative target microsatellite [25].…”