Overview of HESSI:

The online brochure is an illustrated introduction on solar flares and on the HESSI spacecraft 

What are the Scientific Objectives of HESSI? 

Project Highlights


Overview of Solar Flare Theory:

This short overview on solar flares tells you what physical phenomena HESSI will observe. 


HESSI Proposal:

You have some time to study the details? Then look at the complete HESSI proposal for more information 


Hard Facts:

The fact sheet gives you an overview of HESSI by the numbers.



HESSI is a collaboration between different institutions. HESSI-related sites are located at: 

-The NASA/Goddard Space Flight Center in Greenbelt, MD 

-The Paul Scherrer Institute in Switzerland 

-The UCB/Space Sciences Laboratory in Berkeley, CA 

-Spectrum Astro in Gilbert, AZ 


Mission Status and Events

-Small Explorer (SMEX) Science Missions Selected Phase A study completed on January 20, 1998 and presented to NASA.

-Phase A study approved by NASA on February 23, 1998 and Phase B begins...


-Ground Station construction at SSL The dish arrives... October 4, 1999


-Spacecraft Bus arrives at SSL from Spectrum Astro. January 16, 2000



-HESSI Sustains Damage During Vibration Testing.  Press release on incident available. Photos and video clips of spacecraft before the mishap are available here.  March 21, 2000

-Review board finds cause of HESSI mishap.  Press release available.  May 12, 2000

-The Goddard Program Management Council gives HESSI the go-ahead after reviewing the mission's viability following the mishap in March. See "Status & Events" for timeline of events since then.