Geosar: Baseline And Budgets

GeoSAR is the name for a project that aims to place a satellite utilising synthetic aperture radar technology into geosynchronous orbit.

The overall objective for the project was to develop a design for a GEO satellite that would use SAR for a particular Earth-observation related purpose. This satellite would ideally fit in the framework of the ESA Earth Explorer programme, in terms of function and cost.

This article is focussed on three sections of the project: Systems Engineering, Mass and Power Budgets, and Costing.

Systems Engineering covers the group operations and how they linked with each other into a coherent project. This includes details of meeting structure, data collation and progress through trade-off analysis to a final mission concept.

Mass budgeting was initially based upon the principle of past geosynchronous satellites and a shared launch. Following this individual subsystems created mass estimates of their own and fed them back to Systems Engineering. The final mass estimate of the spacecraft was 2069 (+/-207) kg. This was below the original mass budget and well within the envelope for an equal shared launch on a Space-X Falcon 9 launch vehicle.

In the final section of the paper a parametric costing model was used to estimate the possible cost of this mission. The method used Cost Estimate Relationships (CER) to estimate cost based on varying different subsystem parameters. The ESA Earth Explorer guidelines stipulate a total space/mission-specific ground segment cost limit of ?100 million. The final cost estimate of the spacecraft with solely these factors was ?117 million +/- 44 million. This indicates the possibility of the mission falling within the correct budgeting.