The TREND projects
The Trapped Radiation ENvironment model Development study was initiated and funded by ESA under ESTEC Contract No. 8011/88/NL/MAC. It has been followed by the TREND-2 and TREND-3 studies. A fourth contract started on November 1, 1997 and has a duration of 24 months.Institutes participating in TREND
- Matra Marconi (TREND-1)
- Space Technology Ireland (TREND-1)
- Belgian Institute for Space Aeronomy (TREND-1, 2, 3, 4)
- Mullard Space Science Laboratory (TREND-2, 3)
- Max Planck Institut für Aeronomie (TREND-3)
- Département d'Études et de Recherches en Technologie Spatiale (TREND-4)
- Paul Scherrer Institute (TREND-4)
The four studies
- TREND-1: Development Study of Improved Models of the Earth's Radiation Environment
- TREND-2: Trapped Radiation Environment Model Development
- TREND-3: Radiation Environments of Astronomy Missions and LEO Missions
- TREND-4: Time-Dependent Radiation-Belt Space Weather Modelling
UNILIB fortran librairy

UNIRAD software package
ESTEC has developed the software package UNIRAD to estimate radiation fluences and doses accumulated over specified orbits. The ensemble of software routines in UNIRAD has been extended and upgraded at BIRA/IASB in the framework of the TREND-2 contract. A detailed description of the modifications is given in Technical Note 1 and in the latest version of the UNIRAD user manual.
The UNIRAD software package is now part of the SPENVIS system