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Aerospace and Electronic Systems Magazine, IEEE

Issue 4 • Date April 1995

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Displaying Results 1 - 7 of 7
  • Thin-film Li-LiMn2O4 batteries

    Page(s): 30 - 32
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (246 KB)  

    Thin-film rechargeable Li-LiMn2O4 batteries have been fabricated and characterized. Following deposition by electron beam evaporation of LiMn2O4, the amorphous as-deposited cathode films 1 cm2 in area by 0.3to 4-μm thick were annealed at 700/spl deg/C to 800/spl deg/C in oxygen in order to form the crystalline spinet phase. The specific capacity of the cells between 4.5 V to 3.8 V ranged from 50 μAh/mg to 120 μAh/mg. When cycled over this range, the batteries exhibited excellent secondary performance with capacity losses as low as 0.001% per cycle. On charging to 5.3 V, a plateau with a median voltage of 5.1 V was observed. The total charge extracted between 3.8 V to 5.3 V corresponded to about 1 Li/Mn2O4. View full abstract»

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  • High resolution miniature AMLCDs for projection and head-mounted systems

    Page(s): 33 - 35
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (240 KB)  

    The development of advanced active matrix liquid crystal displays is described. The displays are formed from single crystal silicon, and have integrated on-board scanner circuitry for row and column addressing. The display diagonal is 5 cm, and pixel pitch as low as 12 μm is under development. Operational 640 by 480 displays are described, and initial results with 1.250 by 1.024 displays are reported. View full abstract»

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  • Solving radar detection problems using simulation

    Page(s): 36 - 40
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (440 KB)  

    Simulation is a well-known but often misunderstood method for predicting the detection range of radars. Recent advances in computer software and hardware have made simulation easier to apply and use. Users are putting increased reliance on computer simulation in lieu of more expensive test and evaluation. In this paper, a simulation example is given of a complex radar detection problem which is not solvable using conventional procedures. It is shown how this problem is easily solved using a MATLAB simulation on a personal computer (PC) View full abstract»

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  • Charging the new batteries-IC controllers track new technologies

    Page(s): 20 - 25
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (476 KB)  

    Demands for portability have fueled significant developments in new battery technology. These developments have resulted in many more options in selecting the battery type for use in a particular project, but since most applications today are opting for rechargeable battery systems, the availability of battery charging solutions can become an equally important criteria in the selection process. Complicating this process are the demands for fast-but safe-charging with charge algorithms easily implemented with low-cost hardware. With the higher levels of complexity attendant with these more demanding algorithms, solutions have come primarily from the integrated circuit industry and the purpose of this paper is to provide a few examples of the latest efforts in this arena, specifically as addressed to lead-acid, nickel metal-hydride, and lithium-ion technologies View full abstract»

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  • Hubble Space Telescope solar array change-out, mission anomalies and returned flight hardware

    Page(s): 3 - 13
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1392 KB)  

    During the successful First Servicing Mission on the Hubble Space Telescope the two solar arrays were replaced with new and improved solar arrays. An electrical short and four solar array mechanical system anomalies occurred: (1) the upper outer bistem on the +V2 wing had developed kinks and then failed to retract; (2) additional friction between the solar array latch fitting and the aft latch berthing microswitch guard probably caused the failure of the primary deployment mechanism to deploy the solar array wings; (3) the secondary deployment mechanism retract limit microswitch activation is believed to be a result of the dynamic motion of the wings during the retraction event. Successful retraction took place after five attempts; and (4) additional torques induced during extra vehicular activity, flight support system and orbiter activities caused the wings to move from the latching destination. The physical appearance and durability of the materials on the solar array and the physical position of hardware indicators were investigated at Kennedy Space Center after the flight servicing mission. Evidence of micrometeoroid damage and the darkened silicone coatings were apparent. Isolation and continuity tests confirmed the location of shorts which occurred during the First Servicing Mission View full abstract»

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  • Need and effect of reconditioning of nickel/hydrogen batteries

    Page(s): 26 - 29
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (328 KB)  

    There has been a debate about the need for reconditioning nickel/hydrogen batteries in geosynchronous satellites. A study was done as part of life cycling, to determine the necessity of reconditioning and its effect on the cell performance. A 36 Ah nickel/hydrogen cell was put on a GEO simulated cycling at 15°C without reconditioning up to four eclipse seasons. The effect of reconditioning on the fifth and sixth eclipse seasons was studied. The study has conclusively proven the need for reconditioning and has shown the benefits of a high rate reconditioning. It has also been possible to draw some conclusions about the effect of a long duration trickle charge on the positive electrode View full abstract»

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  • Global avionics in the future

    Page(s): 14 - 19
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (480 KB)  

    The following topics are discussed: new batteries for old airplanes; new charge controls for lengthening battery life; fast methods for batteries charging; AC conductance measurement based battery testing; pulse power; bipolar lead-acid batteries vs supercapacitors; Ni electrode cells for spacecraft; worn-out battery disposal; recycling technology; vehicle batteries cost; high energy content batteries; and energy storage for electric utilities View full abstract»

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Aims & Scope

The IEEE Aerospace and Electronic Systems Magazine publishes articles and tutorials concerned with the various aspects of systems for space, air, ocean, or ground environments.

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Teresa Pace, PhD EE
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