RHESSI News Item

HESSI Reconfirmation

I'm pleased to report that HESSI (the High Energy Solar Spectroscopic Imager)
has been reconfirmed for flight by NASA with a new launch date of March 28,

As reported earlier, on March 20, 2000, the HESSI spacecraft was severely
damaged during a vibration test at JPL, when the shake table malfunctioned and
applied more than 20 Gs instead of the 2 Gs called for in the test. This mishap
resulted in the failure of the machined aluminum main support ring for the
Imager, extensive damage to the solar panels, damage to the main deck, and
degradation of the mechanical cryocooler. Since then the damage to HESSI has
been assessed and repairs begun. Luckily, both the Imager and Spectrometer
survived with no major damage. Unfortunately, in mid-May the spare flight
cryocooler began to exhibit anomalous behavior and Goddard is having to qualify
a new cooler.

The HESSI Recovery Plan was reviewed by an independent panel on May 15-16. Their
recommendations and the HESSI project response were presented to the Goddard
Program Management Council in a Reconfirmation Readiness Review on June 29. A
NASA Headquarters Reconfirmation Review was held on August 4, and Edward Weiler,
the Associate Administrator for Space Science, gave the official go-ahead contingent
on the delivery of a flight qualified cryocooler to Berkeley by early September.

Bob Lin