The Next Generation of Gamma Ray Telescopes in Space

The field of high energy gamma-ray astronomy has been redefined by the discoveries of the EGRET instrument on the Compton Gamma Ray Observatory. Breakthrough observations by EGRET of high-energy gamma-ray blazars, pulsars, unidentified sources, delayed emission from gamma-ray bursts and solar flares, and diffuse emission from our Galaxy and beyond, have all changed our view of the high-energy Universe and raised many new questions. Future space missions are now being planned in the US and Europe to make tremendous steps forward. The AGILE mission in Italy will offer EGRET-type sensitivities but with significantly improved angular resolution to enable unique identification of sources. The GLAST mission in the US with major contributions from Europe and Japan will provide enormously improved sensitivity, angular resolution and high-energy (>100 GeV) response. The AGILE launch is planned for 2003 and GLAST in 2005. The science, technologies and observational capabilities for these missions will be described.