1、MIL-STD-1539 (USAF)1 AUGUST 1973MILITARY STANDARDELECTRICAL POWER, DIRECT CURRENT,SPACE VEHICLE DESIGN REQUIREMENTSFSC 1810Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Electrical Power, Direct Current,Space Vehicle Design RequirementsMIL-STD-1539
2、(USAF)1. This standard is approved for use by all Agencies ofthe Department of the Air Force.2. Recommended corrections, additions, or deletionsshould be addressed to:SAMSO/DRUEP. O. BOX 92960Worldway Postal CenterLos Angeles, Calif. 90009Provided by IHSNot for ResaleNo reproduction or networking pe
3、rmitted without license from IHS-,-,-Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-STD-1539 (USAF)ELECTRICAL POWER, DIRECT CURRENT,SPACE VEHICLE D
4、ESIGN REQUIREMENTS1. SCOPEspace vehicles.1.2 Purpose. This standard insures compatibilitybetween the space vehicle dc electrical power system and thespace vehicle utilization equipment. This compatibility isaccomplished by confining the electrical power systemcharacteristics within definitive limits
5、 and restricting therequirements imposed on the system by the utilizationequipment.1 .3 Basis for characteristics. The requirements,characteristics, and vlimits specified in this standard arebased upon the concepts of MIL-STD-704 as modified for spacevehicle applications.2. REFERENCED DOCUMENTSThe f
6、ollowing documents, of the issue in effect on dateof invitation for bids or request for proposal, form a partof this standard to the extent specified herein:Military StandardsMIL-STD-255 Electric Voltages, Alternating and DirectCurrentMIL-STD-704 Electric Powerand utilization, Aircraft, Characterist
7、icsof(Copies of specifications, standards, and publicationsrequired by suppliers in connection with specificprocurement functions should be obtained from the procuringactivity or as directed by the contracting officer.)Provided by IHSNot for ResaleNo reproduction or networking permitted without lice
8、nse from IHS-,-,-3.1.2 Electrical energy storage subsystem. Theelectrical energy storage subsystem includes allrechargeable and all nonrechargeable batteries on the spacevehicle. Instrumentation, heaters, and other controls builtintegral with the batteries are considered part of theelectrical energy
9、 storage subsystem.3.1.3 Power distribution subsystem. The electricalpower distribution subsystem on a space vehicle shall besubdivided into identifiable load groups. The powerin stribution subsystem for each load group originates at apower load bus or terminal in the power control subsystemand exte
10、nds to the input power terminals of the spacevechicles utilization equipments comprising that load group.The power distribution subsystem includes harnesses, cables,conductors , and connectors used in the power distributionProvided by IHSNot for ResaleNo reproduction or networking permitted without
11、license from IHS-,-,-MIL-STD-1539 (USAF)3.1.4 Power control subsystem. The electrical powercontrol subsystem includes the command system interfaces,switches, relays, connectors, interconnect wiring, loadbuses, resetable circuit breakers, fuses, load controldevices, voltage sensors,current sensors, b
12、attery chargers,battery discharge controllers, and other related devicesused to interconnect and control the dc power generationsubsystem, the electrical energy storage subsystem, and thepower distribution subsystem of the space vehicle.Instrumentation, heaters, and other controls builtintegralwith
13、the power control equipments are considered part of thepower control subsystem.3.2 Utilization equipment. Utilization equipmentscomprise all electrical loads external to the dc powersystem to which the specified dc power is supplied.3.3 System ground point (SGP). The SGP is a singlepoint on the vehi
14、cle structure to which the negative or theneutral of the electrical power system is connected.Electrically isolated power systems may have separate systemground points on the vehicle structure.3.4 Essential loads. The utilization equipments thatare necessary for the survival of the space vehicleitse
15、lfare defined as essential loads.3.5 Normal operating modes. The normal operating modesfor the electricalpower system on the space vehicle includeall planned, expected, or commendable operating conditions.These include various load groups cycled on or off , bothsunlight and eclipse conditions, high
16、and low bus voltages,and other predictable operating conditions.3.6 Abnormal operating modes. Abnormal operatingmodes for the electrical power system include thoseconditionsresulting from short circuit failures, or opencircuit failures, or other malfunctions occurring anywherewithin the space vehicl
17、e including within the electricalsystem itself. Other abnormal operating modes includeconditions resulting from temperature extremes that exceedspecified or anticipated values and from excessivedegradation of solar arrays or other power system equipment.-3-Provided by IHSNot for ResaleNo reproductio
18、n or networking permitted without license from IHS-,-,-MIL-STD-1539 (USAF)3.7 Transients. A transient is that part of thevariation in a variable thatultimately disappears duringtransition from one steady-state operating condition toanother. Transients are aperiodic and include nonrecurringcurrent su
19、rges and voltage spikes.3.8 Ripple. Ripple is the cyclic variation of voltageabout the mean level of the voltage during steady-state dcelectrical system operation. The ripple voltage may containmultiple frequencies and includes noisenot generated bytransients. The average value of ripple is zero.4.
20、GENERAL REQUIREMENTS4.1 System. The dc power system for a space vehicleshall be so designed as to ensure that the characteristicsof electrical power at the utilization equipment power inputterminals conform to the requirements specified in thisdocument. The electrical system shall be designed so tha
21、tthe power levels and energy requirements of each of theutilization equipments are satisfiedfor the specifiedservice life of the utilization equipments. The dc powersystem shall be capable of meeting the functionalcharacteristics and design requirements specified hereinbefore and afterexposure to pr
22、eflight environmentalconditions and during all predictable orspecified flightenvironmental conditions.4.2 Voltage limits. The steady state dc electricalpower on the space vehicle measured at the input to theutilizationequipment shall be 28.0 6.0 V during normaloperating conditions.4.3 Power distribu
23、tion. The dc power shall bedistributed using a two wire system. The negative or groundreturn path for all power circuits shall be throughconductors in the wiring harnesses. The vehicle structureshall not be used as an intentional current-carryingconductor.4.3.1 The dc power systemof a space v have t
24、he power negative buses inthe power control subsystem grounded to the vehiclestructure at a single point.This single point shall be-4-Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-referred to herein as the System Ground Point (SGP) . The dcresista
25、nce as measured from the power negative bus to thevehiclestructure shall not exceed 2.5 miillonms. Nogrounds shall be made to magnesium structure.the power system negative buses shall all be connected tothe same SGP. All power return leads from any one loadsupplying that load.4.4 Utilization equipme
26、nt. Utilization equipmentshall maintain its specified performance when using powerwith characteristics which are specified herein. When useof power is required having other characteristics or closertolerances than specified herein, the conversion to othercharacteristics or closer tolerances shall be
27、 accomplishedasa part of the utilization equipment . Utilizationequipment current requirements shall be determined overtheinput voltage range specified herein.5. DETAILED REQUIREMENTS5.1 Nominal time line. A nominal operational timelineshall be established for the space vehicle thatidentifies the pl
28、anned operational configurations and statusof the space vehicle for all normal operating modesincluding acceptance testing, prelaunch checks, launch,orbit injection,attitude acquisition, on orbit, and reentryconditions asmay be applicable. This time line shallinclude the cycling of the various loads
29、 or loadgroups onor off as planned, expected, or commandable for eachoperating mode of the space vehicle. Both sunlight andeclipse conditions, high and low bus voltages, and otherpredictable operating conditions shall be included. Thisnominal operational time line shall be at least as long asthe ser
30、vice life of the space vechicle.-5-Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-5.2 Power requirements of loads5.2.1 Load groups. The utilization equipments are tobe grouped into identified load groups. One or more ofthese identified load groups s
31、hall be used for essentialloads only. The load groups shall be identified with powerhoses or terminals in the electrical power controlsubsystem.5.2.2 Redundant loads. Redundant utilizationequipments shall be placed in different load groups so thatelectrical power will be supplied by seperate wires a
32、nd so5.2.4 Consumed energy. The energy consumed by thedetermined as a function of time based uponpower profile.utilization equipments on the space vehicle shall bethe nominaltime period5.3.2 Energy margins. Energy generating and storagecapabilities in excess of the nominal load requirementsshall be
33、identified as energy margins. Energy generatingand storage margins shall be provided to accommodate thefollowing:-6-Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-STD-1539 (USAF)(a)(b)(c)(d)(e)(f)Inaccuracies in predicting utilization loadrequir
34、ements.The predictable degradation of the electricalsystem that will occur during the service life ofthe space vehicle.Variations in component and end item electricalcharacteristics from unit to unit.Variations in electrical characteristics due tooff nominal space vehicle orbits , stabilization,or t
35、hermal environments.Current limiting operations, the trip bands of theprotection equipment, and other abnormalconditions duringwhich full space vehicleoperations are required.Predictable variations in the nominal time lineand the nominal power profile.The power generating and energy storage margins
36、providedshall be identified as “reserve” unless they are otherwisespecifically identified. For each battery, the maximumdepth of discharge and the number of discharge-charge cyclesused shall be determined as a function of operating time.Redundant power generatngand energy storage componentsshallbe p
37、rovided as necessary to meet the reliabilityrequirementsand service life of the space vehicle.5.3.3 Analysis. The energy analysis of the electricalpower system operation shall becoupled with the thermalanalysis so that any effects of temperature on componentelectrical characteristics will be conside
38、redduring allnormal operatingmodes as well as during possible abnormaloperating conditions. The thermal analysisshall includethe effect of internally generated heat within theelectrical power system during all normal operating modes aswell as during possible abnormal operating conditions.5.3.4 Power
39、 control. The power control subsystemshall be designed to regulate and control the electricalpower generation,energy storage, and power distribution-7-Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-subsystems to satisfy the dc power requirements of
40、the spacevehicle.5 .3.5 Charge control. When battery chargedischarge controls are used, separate controls shall beprovided for each rechargeable battery or system ofrechargeable batteries connected in series to provide therequired bus voltage.5.4 Failure protection5.4.1 Fault isolation.shall include
41、 fault isolatloncircuits in the utilizationdistribution subsystem whichThe electrical power systemthat protects against shortequipment or in the electricalcould adversely affect theelectrical system operation. The fault isolation shalleither open the circuit to remove the load and short circuitfromt
42、he load bus or shall limit the current so thatelectrical power characteristics to other loads remainwithin the specified limits. Provisions shall not beincluded for fault. isolation of nonredundant essentialloads.5.4.2 Power control. The power control. subsystemsshall be designed, installed, and pro
43、tected so that thefailure of any power source will not result in subsequentimpaired performance of the remaining power sources.5.4.3 Battery failure. The installation of thebatteries shall include provisions that minimize damage tothe spaceof a majorconsideredany of theexcessivecells.5.4.4electrical
44、vehicle and to the electrical system in the eventfailure of the battery. The major failures to beinclude, but are not limited to, an explosion ofbatteries due to the internal generation ofgas or a massive short circuit involving multipleOvervoltage and undervoltage. Failures in thepower system that
45、can result in voltages higheror lower than specified herein being applied to utilizationequipments shall be identified as critical failure modes.-8-Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-5.5 Power quality5.5.1 Ripple voltage.less than 0.V pe
46、ak-to-peakfrom dc to10 megahertzdelivering the maximum ratedThe ripple voltageas measured over the(MHz) when the powercurrent into resistive loads.5.5.2 Transients. Generation of voltage transients anthe dc electricalpower by load or source switching shall belimited to 28-V peak measured from the st
47、eady state value.In addition, the integrated area under the transientvoltage-time function shall not exceed 0.003 volt-seconds.5.5.3 Bus impedance. The impedance of the powersources measured at each of the load buses shall bedetermined analytically to be sufficiently low over afrequencyrange from dc
48、 to 50 MHz SO that conductedinterference voltages produced by utilization loads will notbe excessive.5.5.4 Power transfer. Switching of power sourcesshall not result in power loss to any utilization equipmentthat exceeds 50 milliseconds. The current surges resultingfrom switching power sources or ut
49、ilization equipments on oroff shall not cause the voltage limits, transients, or powerquality to exceed the values specified herein.6. NOTES6.1 Deviations. Variations to the voltagecharacteristics specified in 4.2 and 5.5 of this standardmust be approved by the procuring activity. Variations thatare cost effective and that enhance the total
