TRACE Integration and Test Monthly Update
TRACE Integration and Test Monthly Update
May 1st thru May 31st
The month of May proved productive as the TRACE spacecraft completed it's Pre-Environmental comprehensive test program with minimal difficulties and moved through both Mass proerties and acoustic testing. Additionally, the TRACE team decided that it was best to replace the discolored primary mirror with the backup mirror, which has yet to have it's UV quadrant coated.
There were some minor software bugs that were worked out this month, mostly within the instrument code, as the TRACE software team, lead by Mike Levay and Mike Blau, loaded the latest build of code into the spacecraft. Subsequent tests, those that could be accomplished without the stimulation telescope, proved the software build was indeed running smoothly. More testing will be accomplished post EMI/EMC testing. With the software running smoothly, Joe Burt decided that all was well with the spacecraft, that the comprehensive test objecives were met, and that the spacecraft was ready for the environmental test program.
Meanwhile, Mike Adams and his mechanical team, completed integration of all the flight solar array mechanism components and successfully completed not one but two,deploy tests. (see other links to video clips!). Furthermore, Mike, in concert with Omar and the blanket shop completed all major blanket work in time for Mass properties and the spacecraft acoustic test.
The most serious issue dealt with this past month was what to do about the primary mirror coating discoloration. After much inspection and consultation with GSFC and SAO and SLISR experts, it was deduced that the discolortion was indeed the result of contamination. Also determined, was the usability of the mirror as is; i.e if the discoloration did not grow, the mirror could be used as is. Unfortunately, no one could determine the risk of the discoloration growing into the usable UV quadrant field of view. Therefore, it was decided that, if the backup mirror UV quadrant were cleaned prior to it's coating - something not done with the first primary mirror UV quadrant - it would be benefitial to swap mirrors.
Presently, the spacecraft is in the EMI/EMC facility undergoing a battery of tests. Once completed, the spacecraft will be moved back to it's clean tent so that the telescope may be removed for shipment back to SLISR in Palo Alto, where the mirror swap will take place.
April 21st thru April 25th
The SLISR and GSFC teams, in concert with the UV quadrant coatings supplier, ARC, continued the investigation into the cause and potential impact of the discolored primary mirror.
Also out at Palo Alto, testing/troubleshooting of the wedge motors continued with no conclusions yet as to why the motors get 'stuck'.
Ace technicians Rich Hoffman and Shirley Paul continued their work on the harness as they supported the removal of the Transponder (for polymetrics work on the EMI ferrite beads in it's harness) the Gyro box (it needed new heaters in a different location) and the Qual Battery. Moreover, they continued wiring up the wax actuator harness, the technology infusion experiments, and in general have yet to see the light of day as they have worked steadily for 5 days putting the finishing touches on the harness.
Mike Adams and his team (Steve PAtton and Yoon) finished the installation of the flight wax acuators and drilled new mounting holes for the two technology infusion experiments and the purge line fittings.
Dave Jung and Dave Sullivan spent late Friday performing electrical integration procedures in preparation for charging the flight battery over the weekend.
April 14th thru April 18th
"Yow" exlaimed mission manager Gerry Daelemans, as it was discovered this week that there was discoloration found on the uv quadrant of the primary mirror. Close up photos were taken and both the GSFC and SLISR teams are deeply into investigating the cause of the 'pink eye' and what the potential impact to the mission might be.
As of this writing it is not known how the 'pink eye' came into being, although many feel it is a latent contamination induced discoloration.
Also this week, what was thought to be perhaps a software problem commanding the guide telescope wedge motors indeed turned out to be a problem with the motors themselves. The SLISR team, led by Jake Wolfson, removed the wedge motors early Friday, sending them back to Palo Alto for further testing/troubleshooting.
On a more positive note, comprehensive testing continued with the successful completion of a Spacecraft/Instrument ACS phasing and latency tests. Previously, these tests revealed software p problems which have not been corrected.
April 7th thru April 11th This week saw all of the ACS comprehensive tests completed; these tests included: ACE box hardware functional tests, ACS Software tests, ACS sensor/phasing tests and two dynamic simualtion using the instrument wedge motors in the loop.
Also this week, the instrument team continued their debug of some minor software problems
March 31st through April 4th
The Spacecraft comprehensive tests began in earnest this week as Tom Spitzer completed all of his power systems tests.
Debugging of the instrument software problems continued and some progress was made, though not all the bugs are understood. The Instrument team did manage to complete all the instrument functional test sequences verifying that all TSTOL procedures have been wrung out and that the instrument mechanisms can be controlled via the IGSE and Spacecraft systems. The instrument team then retreated to Palo Alto to continue their debug effort.
Mike Blau and his team of crack software gurus successfully loaded and tested the lasted flight software build and eagerly await the continuation of the spacecraft comprehensive tests to verify thier handy work.
March 18th thru 28th
Instrument to Spacecraft troubleshooting continued this week as a boot up problem with the instrument DPU was traced to a missing + volts on an integrated circuit pin. The culprit was found in the artwork of the PC board which failed to connect the +5V plane with the IC.
When the DPU was removed for the aforementioned troubleshooting, some minor workmanship issues were discovered necessitating further disassemble and inspection of the DPU. All these problems were resolved to the satisfaction of all and the DPU was re-assembled and reintegrated on the spacecraft late Thrusday 3/27.
Further testing on 3/28 revealed still yet somemore bugs believed to be within the instrument software. Confident that the spacecraft bus software was rung out, Mike Blau and his crack team of software gurus retreated to the lab for build 3 of the flight software; targeting Friday 4/4 for spacecraft load.
March 10th thru 17th
Spacecraft to Instrument integration and troubleshooting activities were put on hold this week as Mike Adams and his team of mechanical techs/engineers moved the spacecraft to Building 29 and installed the flight solar array mechanisms and g-negation hardware.
At the weeks end, the g-negation system was tested successfully and all solar hardware was integrated.
Mike and his team moved the spacecraft back to the TRACE clean tent early Monday March 17th.
March 3rd thru 7th
For those that love scratching their heads contemplating the intricacies of flight software this past week was your week, as Instrument functional tests revealed some bugs in the flight software.
A step by step functional test of the instrument, via the spacecraft bus, showed all major mechanisms were operation properly. It was only when high speed commanding of the instrument, as part of a CCD image capture sequence, did a problem arise. Tests are underway to fully comprehend what appears at this time to be software related anomaly.
Meanwhile, the team prepared the spacecraft for it's move to building 29 where the flight solar arrays will be installed, and the g-negation system hardware - used during thermal vac testing of the solar arrays - will be checked out.
The problems with the flight software will be revisited when the spacecraft returns from it's solar array activities.
February 24th thru 28th, 1997
A major milestone was reached this week as the TRACE telescope was successfully mechanically integrated with the spacecraft bus.
Led by Mike Adams, GSFC and a team of Lockheed engineers, took the better part of 2 hours to perform all the lift operations as well as bolting and torquing all the fasteners.
Presently, the team is performing safe-to-mate electrial procedures in anticipation of begining instrument functional tests early next week.
January 21st thru February 14th, 1997
My apologies constant reader for neglecting to update you more swiftly on the daily integration and test activities as they occur.
The last few weeks have seen the completion of all major spacecraft bus integration and test activities.
Once the two damaged solar arrays were repaired - each had two cracked cells - they were successfully integrated onto the spacecraft with the latch and release mechanisms and the hinge/dampler mechanisms. Moreover, a deployment test, with all the associated S/A to s/c harnessing attached proved successful. Later the arrays were removed and the spacecraft returned to it's vertical position.
Omar Quinones and his team of thermal technicians have completed testing of all the spacecraft bus thermal systems and verified their correct location/cross correlation with telemetry pages. Also, the spacecraft has been fitted for blankets as that work is now proceeding.
Mike Blau and Jonothan Wilmot, CnDH and ACS software gurus', loaded the spacecraft with the latest flight software; this software had just completed acceptance testing with only a few minor bugs to be patched at a later date.
The last few days Jackie Mims and Teresa LaFourcade and Jonathan Wilmot have been debugging the TREND UP, TREND DOWN, and ACS procedures, respectively.
Only minor touch up work to the harness and another round of cleaning the spacecraft remain to be done before the arrival of the intrument which is being eagerly anticipated for Feb. 24th.
January 17th, 1997
The team began winding down for the weekend with an easy day of ACS gyro phasing tests - all completed successfully.
The solar arrays have completed their stand-a-lone tests and cracks were discovered on three cells spread over two solar arrays. It has been decided to go ahead and integrate the two good arrays beginning Monday, while waiting till the second two arrays are repaired before integrating them.
On the instrument front, the weeks end saw the completion of all post ship functional tests and the beginning of the DPU electronics box vibration test. This weekend, Saturday and Monday, the Telescope itself will be vibrated.
January 16th, 1997
The spacecraft took it's first flight today as it was moved from the vertical test stand to the turn-over fixture in anticipation of tomorrows gyro phasing test, to be led by Darrel Zimbelman.
As planned, Darrell and his team completed their ACS subsystem long functional late yesterday evening with only a few data points requiring some investigation.
Later in the day, the team, led by Joe Burt spent time refining some STOL test procedures.
January 10th thru 15th, 1997
GSE Gremlins delayed the completion of the post-move spacecraft functional til Monday January 13th, but much progress has been made in the day's since.
The battery was installed last Friday the 10th and fully charged on the 14th.
Darrell Zimbelman is taking his team thru a round of GSE calibrations as well as a repeat of the spacecraft ACS long functional. These activities are on track to be completed today, January 15th.
The TRACE telescope arrived safely this past weekend and has completed it's post ship functional tests and is now awaiting vibration testing late this week.
January 9th, 1997
Well, I'm back constant reader...and so is TRACE!
The spacecraft laid still for the holidays as the team took time off from integration and test. January 6th and 7th saw the spacecraft move from building 5 to building 7. A successful move, pulled off by the excellent work of Rich Hoffman, the spacecraft now stands ready to resume it's journey through Integration and test.
Today January 9th, the spacecraft was powered successfully. A faulty diskdrive cable in the TCW workstation and a loose cable behing the multitude of racks slowed what was supposed to be an early power up this morning.These problems were fixed, and the spacecraft came alive late this afternoon delivering it's telemetry to everyone's satisfaction.
Tomorrow will see the completion of the 8 hour spacecraft function and battery installation.
Of great anticipation by all is the arrival of the TRACE telescope this weekend.
To return to the TRACE Integration and Test Activities Home Page.