Enhancing MSS Software to Meet the Evolving Needs of the ISS

Paper number

IAC-05-B4.4.02

Author

Ms. Pat Greene, MDA, Canada

Year

2005

Abstract

The Mobile Servicing System (MSS) is critical to the assembly and operation of the International Space Station (ISS).  It consists of the Space Station Remote Manipulator System (SSRMS), the Mobile Base System (MBS), both currently on-orbit, and the Special Purpose Dexterous Manipulator (SPDM) which is to be launched in 2007. These elements are controlled within the ISS from one of two Robotics Workstations (RWS).

The more than 4 continuous years of successful operation logged on orbit, have not come without a few anomalies and problems.  For the most part, these have been overcome through a  flexible software architecture.  This was never more evident than in the case where the ISS crew was preparing to dry run the S0 Truss Segment installation procedure and the SSRMS suddenly applied its brakes by “safing” and they could not be released.  Software patches allowed this mission to continue with minimal delay. 

This flexible architecture has also provided the means to progressively enhance the MSS functionality as the need for mission capabilities arises during on-orbit operations and mission planning.  One example of such an adaptation is the seemingly impossible task of installing the P5 Truss Segment robotically with less than 3 inches of clearance from a piece of equipment that was not designed for impacts and which has 200 amps of current flowing through it. All of which is required to be performed with the crew in their space suits in the vicinity.

This paper discusses how the MSS software has been adapted and modified to resolve challenging on-orbit anomalies and provide significant functional enhancements to meet new and previously unidentified mission requirements.

Abstract document

IAC-05-B4.4.02.pdf

Manuscript document

IAC-05-B4.4.02.pdf (🔒 authorized access only).

To get the manuscript, please contact IAF Secretariat.