The purpose of the HEASARC is to support a multi-mission archive facility in high energy astrophysics for scientists all over the world. Data from space-borne instruments on spacecraft, such as ROSAT, ASCA (formerly Astro-D), GRO (Compton), BBXRT, HEAO 1, HEAO 2 (Einstein), EXOSAT, and XTE are provided, along with a knowledgeable science-user support staff and tools to analyze multiple datasets. The HEASARC activity is a joint effort between the Laboratory for High Energy Astrophysics (LHEA) and the National Space Science Data Center (NSSDC).