Status & Events

April 2001 (VAFB):

• Continuing Attitude Control System simulations and tests.
• Continuing to practice flight operation procedures.
• Moved spacecraft to Bldg 1555 at VAFB.

March 2001 (VAFB):

• Completed setup of Hot Bench at UCB and performed Attitude Control System simulations and tests.
• Moved spacecraft and GSE to Building 1610 on higher ground at VAFB to avoid power outages and flooding.
• Completed 4 Day No Command test.
• Practising flight operations procedures.

February 2001 (VAFB):

• Attached solar panels and performed 1st Motion Test.
• Repeated spacecraft and instrument functional tests.
• Reviewed and tested flight operations procedures.
• Presented mission status and readiness to PreShipment and Red Team Reviews.

January 2001 (JPL and VAFB):

• Spacecraft returns to thermal vacuum for testing of cryocooler performance at 50W and amplifier trims. Thermal Vacuum successfully concluded on January 8.
• Mass Properties Measurements and Spin Balance performed on January 9 and 10.
• Spacecraft transported to VAFB on January 12.
• Setup and Safe-to-Mate testing performed January 13-14.
• Spacecraft functionals and calibrations successfully performed on Jan 15-17.

MAJOR HESSI EVENTS DURING 2000

December:

• Solar array deployment in thermal vacuum successfully tested.
• Endurance thermal-vacuum testing including hot and cold dwells and extended thermal balance testing.
• Learned that spectrometer is colder than expected at planned cryocooler power level. Good news: we can operate with less power.
• Observed hf noise on two detectors.
• Made amplifier trims to correct noise problem.

November:

• Spacecraft transported to JPL on November 1-2.
• Preliminary setup and testing performed.
• Solar Arrays attached and deployment tested.
• Vibration testing of X , Y and Z axes successfully completed.
• Separation/shock testing successfully completed.

October:

• Flight battery reconditioned and installed.
• Spacecraft fully functional and running.
• Red Team and Pre-Environmental Reviews.

September:

• Ran and passed the following spacecraft functional tests: command and data handling, inertia adjustment device, thermal, launch vehicle interface, electrical power system.

August:

• The Spacecraft Electronics Module, Solid State Recorder, Sun Sensors and Magnetometer have been returned from subcontractors and re-installed on the spacecraft. All units checked out OK.
• Requalified Transponder and RF Switch received and installed on the spacecraft.
• Safe-to-Mate functional tests run for all components.

July:

• Solid State Recorder, Transponder, RF Switch, Sun Sensors and Magnetometer all removed from the spacecraft and delivered to the subcontractors for retesting and qualification.
• The Spacecraft Electronics Module completed testing at Spectrum Astro by the end of the month and checked out OK.

June:

• New deck completed and installed.
• Refurbished bus structure completed and aligned.
• New imager support ring completed and installed.
• Implementing several plans running in parallel to provide new spectrometer cryocooler.
• New solar array substrates completed at COI.
• Requests for Action received from May review team.  Spacecraft Electronics Module shipped back to Spectrum Astro.
• GPMC authorizes new integration, test and launch plan on condition that cryocooler issue is resolved by September. New launch date set for March 2001.

May:

• Spacecraft minus imager and spectrometer taken to Bell Labs for thermal test.  From May 2 to May 5 spacecraft undergoes 6 cycles between +45 and -20C.  Spacecraft passes all functional tests except for firing of frangibolts.  Problem is found to be a  broken wire which is fixed.  All other wiring is scrutinized and plans prepared for high pot and other testing.
• Designed stronger imager support ring.
• Decided to repair broken solar panels and also contract new panels to have two options and choose the best in future.
• Honeycomb deck found to be slightly warped.  Began fabrication of new deck.
• Spectrometer cryocooler found to have deteriorating performance since mishap.
• Spectrometer cryocooler flight spare starts also exhibiting problems during burn-in tests.
• Termination/Recovery Review held at UCB on May 15 and 16.
• HESSI Test Mishap Investigation Board issues their report on May 18.
• After the thermal test and fix of frangibolt wiring, spacecraft is powered up and running most days.
• Flight operations team continues preparations,  including simulations of Launch and Early Orbit plus regular passes.

April:

• Spacecraft carefully inspected and found to be in good shape with the following exceptions:  two damaged solar arrays,  broken imager support ring,  one strained cable.
• Review meeting between GSFC and UCB held on April 4.  Recommendation is to do more inspection plus a thermal test.
• Imager (which rests on the broken imager support ring) shipped to PSI so they can fully test and recalibrate.
• Spectrometer removed and tested for leaks.  None found.

March:

• Solar arrays integrated and thermal blankets installed.
• Spacecraft shipped to JPL.
• Pass EMC testing.
• Pass random vibration testing.
• Spacecraft over-vibrated in sine-burst test (20 G's applied instead of 2 G's for 200 milliseconds).
• Review team gathered to investigate the over-test.
• Spacecraft shipped back to UCB for inspection and evaluation.

January/February:

• Spacecraft Bus delivered to UC Berkeley.
• All instruments successfully integrated and tested at UCB's Spacecraft Integration Facility.
• Pass Environmental Reviews.
• Successful end-to-end testing of telemetry and commands between spacecraft and ground system via the 11 meter antenna.