ACCESS Home What's New ACCESS Science ACCESS Team Why is ACCESS Important? ACCESS Facts ACCESS Instruments

Advanced Cosmic Ray Composition Experiment for the Space Station

Why Is ACCESS Important?

Cosmic rays are one of the few samples of matter we have from outside our Solar System, for comets and large meteorites that bombard the Earth all originate from within our Solar System. Cosmic rays, therefore, carry great histories. ACCESS' goal of detecting galactic cosmic rays will help piece together where they came from and contribute to our understanding of the structure of the Universe.

We know from previous research on the origin of the elements that heavier elements are created as a star depletes its nuclear fuel of the lighter elements, hydrogen and helium. Lighter elements fuse into heavier ones. When a star explodes, these heavier elements fly into space, often creating even heavier elements, such as uranium. The elements are accelerated to nearly the speed of light by a mechanism not well understood. ACCESS will collect and analyze these elements produced, perhaps, by exploding stars millions of years ago.

A service of the Laboratory for High Energy Astrophysics (LHEA) at NASA's GSFC
Author: Chris Wanjek
Responsible NASA Official: Robert Streitmatter

Astrophysics questions? Ask Us
NASA-specific questions? Try the NASA home page or start at the NASA site map
ACCESS Web page questions or comments? Email the Web curator, Beth Jacob, SP Systems

NASA website privacy statement | NASA IT Security Warning Banner