Sequence of images showing the MOC 2 optics structure and focus test equipment immediately after a 14 day vacuum bakeout to remove moisture from the graphite/epoxy structure. Optical Corporation of America Applied Optics Division (OCA) was prime contractor for the optics/structure, responsible for this test at the facilities of Composite Optics, Inc. (COI), who fabricated the structure.
Sequence of images showing the folding of the MOC electronics at Caltech. (A & B) Folding Leading Digital Boards towards Analog Board (beneath Interboard Shield and Heater, center of image). (C & D) Folding Trailing Digital Board towards Leading Digital. (E) Flipping the three-hole handling fixture prior to transferring the stack of boards to the conformal coating fixture (F).
Integration of the electronics into their cylindrical housing was accomplished the last week of June 1995. The process is illustrated in these pictures: (A) The three, double-sided, aluminum honeycomb board assemblies supported by their handling fixture. (B) Removing the interboard spacers. (C) Inserting the boards into the cylinder. This process involves clocking the electronics through several "shelves" created by the mounting points for the shock-absorbing flexures. (D) The electronics in their final configuration.
Mating of the focal planes, in particular the high resolution, narrow angle (NA) focal plane assembly, was also accomplished the last week of June 1995. The process is illustrated in these pictures: (A and B) The NA FPA is attached to the electronics handling rods. (C and D) The NA FPA is drawn towards the "Leading" half-system analog board using the handling rods. The three small screws protruding from the FPA are used to hard mount the FPA to the primary mirror hub, thus firmly fixing the FPA to the optical bench of the NA telescope. The NA shim (not shown) attaches to these screws and fits between the front of the FPA housing and the hub. (E) Attaching and locking down the flex cable that feeds power and clocks to the FPA and returns data. (F) The NA FPA mated to the electronics.
The major milestone in Flight Unit integration is the mating of the optics/structure with the electronics, since they have followed separate paths from design until this point. This is the first time the instrument as it will fly to Mars is all together. Integration was finished on Friday 30 June 1995. These pictures show part of the process: (A) Preparing the sling to support the optics/structure as it is mated to the electronics. (B) Lifting the optics/structure into the support sling. The optics/structure, although voluminous, weighs only 9.7 Kg (21 lbs). (C) Moving the optics/structure towards the electronics. Note the home in the insulating Kapton-coated mylar insulation--that is the primary mirror hub into which the NA FPA fits and to which the FPA is attached. (D and E) Before and after reaching the final mated position. There are 36 screws that hold the skirt attached to the Main Body Support Assembly (MBSA), i.e., the bottom of the optics/structure, to the electronics cylinder. (F) A view down the aperture of the NA telescope (3.5 m focal length, 35 cm aperture). The white rectangle with the dark slit immediately above the NA telescope is the front of the Wide Angle Support Structure. The WA cameras are mounted inside this housing. Since the MOC uses line arrays, the only field of view that is needed is visible through the slit.
MOC 2 Through-focus Pinhole Measurements
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Through-focus measurements made with a moving pinhole target (i.e., one moving back and forth through the MOC field of view). Images were acquired at best focus and up to 30 mils on either side of best focus, by moving the target in the collimator. The oscillatory motion of the moving target generator is termed "to" and "fro." Note that the astigmatic image provides consistent information on direction to best focus. The MOC is focussed in-flight using heaters that change the shape of the primary mirror. MOC 1 had a -25 to +50 mil focus range using 4 W heaters (redundant heaters could provide about twice that range if necessary). For reference, the difference between room temperature and operating conditions at Mars is roughly 60 mils. The MOC 2 location of best focus and focus heater control range will be determined during thermal/vacuum testing.
MOC 2 on Z-shaker head at JPL. Low level sine-vibration sweeps were conducted to confirm the model values, and then a series of force-limited random vibration tests were conducted, culminating with a test at Flight Acceptance levels. The MOC 1 was subjected to Protoflight Level tests with no adverse effects.
MOC 2 on the Y-shaker head (JPL Bldg. 144
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MOC 2 on Y-shaker head at JPL. Low level sine-vibration sweeps were conducted to confirm the model values, and then a series of force-limited random vibration tests were conducted, culminating with a test at Flight Acceptance levels. The MOC 1 was subjected to Protoflight Level tests with no adverse effects.
MOC 2 Shake Team
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From left to right, Steve LeBrecque (Caltech), Rick Stiebel (JPL/MOC QA), Jose Tamayo (Caltech), and Roger Applewhite (Applewhite & Co., MOC 2 Environmental Test Cognizant Engineer).
MOC 2 in TRW Thermal/Vacuum (T/V) Chamber. View into T/V chamber prior to closing door. The MOC 2 and the Collimator (which is the MOC Engineering Model optics/structure) are both about 80 cm long and 40 cm in diameter. A Newport air-ride optical bench is used to isolate the optical tests from vibration from machinery associated with the vacuum system. The "Mars" and "Earth" Plates are used to maintain the MOC and Collimator primary mirrors at their respective operating temperatures when not taking pictures. The Collimator is maintained at "room temperature" (about 23° C), while the MOC is taken to various operating conditions (Inner and Outer Cruise, Approach, Perihelion, Aphelion) using heaters. MOC entered the chamber in early August; focus position, focus control, and functional and photometric performance tests will run through mid-September. MOC 2 is scheduled for delivery to Lockheed-Martin in Denver around 1 November 1995.
"Naked" MOC 2 in Caltech cleanroom after thermal/vacuum testing at TRW. The "workhorse" multi-layered insulation (MLI) external thermal blanket, the carbon-filled Kapton® internal blankets, and aluminized Kapton® bakeout heater have been removed to permit inspection following thermal/vacuum testing. Present activities include test and evaluation of potential replacement Blue Wide Angle CCDs (the present Flight CCD is somewhat noisy at room temperature, where most of the piece-part calibration data are taken), analysis of thermal/vacuum test data to determine the location of best focus (a decision to shim the narrow angle focal plane to the anticipated mean martian focus position will be made in the next two weeks), completion of calibration measurements and first-pass analysis, and preparations for the Instrument Delivery Review (IDR), now scheduled for 26 October at Caltech. MOC 2 is still scheduled for delivery to Lockheed-Martin in Denver on 1 November 1995.
"Publicity" photograph of the MOC 2 in the Caltech cleanroom, taken just prior to packing the camera for transport to Lockheed Martin Astronautics in Denver. The "workhorse" thermal blanket, used during MOC subsystem environmental testing, was re-installed after inspection to act as a guide to LMA thermal blanket designers to improve the "fit" of the flight blankets.
MOC 2 was transported 27-28 November and arrived at LMA on 29 November. Pre-delivery performance/acceptance tests were performed thereafter, and the instrument was mounted on the spacecraft on 7 December. The Initial Power Turn-On (IPTO) Test was successfully conducted the following day. The Functional/Electrical Test (FET), scheduled for Saturday, 9 December, was postponed until 18 December. The FET was conducted with remote participation by the MOC team from the MSSS Flight Operations Center in San Diego. The mechanical and electrical installation of the MOC is complete, and the MOC is fully operational on-board the MGS nadir equipment deck. A report on these activites is being prepared and will be added to this page when complete.
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