Spacecraft Systems exam 2

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Spacecraft Systems exam 2
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2014-03-05 22:45:22
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  1. The heart of a digital computer is the _____ processor unit
    CPU
  2. The two basic types of digital computer memory are ____ and ____
    RAM and Bulk
  3. Commands sent to a spacecraft data handling system are processed with the ________ _________
    command processor
  4. The three types of digital computer hardware topology include _____, _____, and _____
    Bus, Multiplexed, andhybrid
  5. Two types of digital computer redundancy include _______ and ______
    dedicated and shared
  6. In digital systems, _______ errors are called soft errors
    recoverable
  7. Spacecraft are protected from all but the most extreme radiation damage by a process called
    radiation _______.
    hardening
  8. Spacecraft Command and Data Handling (C&DH) system reconfiguration is necessary for to provide ____ and/or ____ recovery and future ________.
    enhancements
  9. _______ is needed in spacecraft C&DH systems to avoid catastrophic errors and component failures
    Redundancy
  10. _____ is the term commonly used for measuring the computing speed or power for a computing system.
    MIPS
  11. The highest-order control on a digital command and data system is called _______ control
    executive
  12. The first manned spacecraft outfitted with a digital command and data-handling system was the ______ capsule.
    Gemini
  13. Computer designed for the ______, ______, and ______ manned programs used ferromagnetic core memory units.
    Gemini, Apollo, and Space Shuttle
  14. Both the Apollo ______ Module and the ______ Module used identical digital computer processors
    Command and Lunar
  15. The first space program to use integrated circuits (microelectronics) for its digital processing system was NASA's _____ program
    Apollo
  16. The first manned program to use a triple-redundant digital processing system and validation voting was the ______ program
    Skylab
  17. The Space Shuttle Digital Processing System
    incorporates ___ separate General Purpose Computers
    5
  18. The Space Shuttle Digital Processing System has ___ entirely independent sets of operating software.
    2
  19. The four basic elements of the spacecraft communications system are
    • Transmitter
    • Receiver
    • Data Management System
    • Antenna
  20. _______ communications systems have both a forward and backward (uplink and downlink) communications link
    Spacecraft
  21. The low voltage/current signals found in many sensors are increased to digital circuit voltages by using a ______ _______
    signal conditioning
  22. The conversion of signals from a transmitter's lower-power signal modulator to a high power signal level at the transmitter antenna is accomplished with a ______ ______
    power amplifier
  23. The typically weak signals received at the antenna input of a spacecraft receiver are increased in strength by a _______
    preamplifier
  24. Multiple sensor signals converted to serial information for transfer through the communications system is accomplished by the use of a ________
    multiplexer
  25. Mixed data on a serial line can be converted to parallel destination lines by using a _______
    demultiplexing
  26. The basic modulation process combines the data signal with the carrier signal at the ____ frequency to allow transmission at the proper transmission frequency.
    radio
  27. The gain of an antenna increases or decreases with operating frequency (f) by a factor of f ______
    squared
  28. The gain of an antenna increases or decreases with the antenna diameter (d) by a factor of d ______
    squared
  29. Is there a gain difference for an antenna that used for transmitting signals and the same
    antenna used for receiving signals?
    No
  30. Is there a difference in the beam width for an antenna used for transmitting and the same antenna used for receiving?
    No
  31. Communications system receivers often experience interference signals (noise) through the antenna ______
    sidelobes
  32. The two most common types of signal modulation are ___ Modulation and _______ modulation
    CW Modulation and PM-pulsemodulation
  33. To prevent either accidental or malicious interference with spacecraft control, the uplink and downlink communications signals are _____
    encrypted
  34. A/an _____ antenna is used as a standard to measure or compare other antenna types.
    dipole
  35. The central frequency of a communications signal is _______ if the spacecraft is moving away from the ground station.
    decrease
  36. The central frequency of a communications signal is _______ if the spacecraft is moving towards the ground station
    increased
  37. A linear vertical antenna receives ___
    of the signal from a linear horizontal polarized transmitted signal.
    0
  38. A linear horizontal antenna receives ___ of
    the signal from right circular polarized transmitted signal.
    ½
  39. The bandwidth of a communications system is typically defined as the signal width measured inside ___ of the maximum (peak) power
    ½
  40. The dB value corresponding to a power (ratio) gain of 10,000 is ___ dB
    40
  41. The power ratio corresponding to a gain of 3.45 dB is _____
    5.25
  42. The three atmospheric windows are found in the _____, ______, and ______
    infrared, the radio, and the microwave
  43. S-band microwave frequencies span ___ to ___ Gigahertz (GHz).
    2 to 4
  44. A signal-to-noise ratio of ___:___  is considered
    reasonable for the reliable reception of signals with a simple communications
    system.
    3:1
  45. Spacecraft communications systems use _____ ______Modulation
    Pulse Code
  46. The Project Mercury capsule
    had a total of ____ separate telemetry data parameters
    97
  47. The first manned spacecraft to use digital telemetry was _____
    Gemini
  48. The Apollo Command Module used a total of ____ telemetry instrument parameters
    403
  49. The International Space Station has more than ________ telemetry instrument parameters
    25,000
  50. NASA's four primary Ground Network (GN) installations are the ____, the _____, the ____, and the ____.
    DSN, STDN, WFF, WATR
  51. NASA's Space Net includes the ______ network.
    TDRSS
  52. The ground station for NASA's TDRSS satellite communications network is located in ______ ______, New Mexico.
    White Sands
  53. Deep-space missions are supported by NASA's ____
    JPL
  54. The Deep-Space Network includes network antenna facilities at __ sites around the world
    3
  55. NASA's Deep-Space Network handles __-band,
    __-band, and __-band communications
    • S-band
    • X-band
    • L-band
  56. NASA's TDRSS satellite network handles __-band, __-band, and __-band communications
    • S-band
    • C-band
    • Ku-band
  57. The TDRSS ground station has __ entirely independent network facilities.
    2
  58. TDRSS communications are available for spacecraft in ____-Earth orbit.
    low
  59. The _______ provides highly reliable communications with secure access to protect the space assets of the U.S.
    NASCOM
  60. NASA's ____ provides links between NASA headquarters, NASA installations, remote facilities, contractor facilities, and universities
    PSCN
  61. Quantization error would be ________ if
    the data resolution (number of signal levels) in a data system were decreased.
    increase
  62. What is meant by the term MIPS?
    Millions of Instructions per Second- measure of the processing power and speed of the computer
  63. The Nyquist sampling rate for a signal frequency of 12 MHz is __ MHz
    24
  64. Electrical power sources available for short-duration (several hours to several days) space missions at high power levels include ____ ____ and ___ ____
    Fuel Cells and Solar Arrays.
  65. The lowest cost electrical power sources available for short-duration space missions at low power levels include ______.
    batteries
  66. Electrical power sources available for deep space (long-duration, > 2 AU) missions (months to years at high power levels include _____ _____ and ______ _____ ______.
    Nuclear Reactors and Radioisotopic Thermal Generators
  67. The _______ principle describes the production of electrical energy from photon energy.
    photoelectric
  68. The output power of a solar cell would _______
    if the photon energy (frequency) were less than that needed to dislocate electrons (approximately 0.6 V).
    decrease
  69. Electrical voltage or current produced in a photovoltaic array would _______ (increase/decrease/stay the same) if higher-than-minimum energy photons were used to illuminate the solar cells.
    decrease
  70. Output power of solar photovoltaic cell would ________ (increase/decrease/stay the same) if the temperature of the cell is increased
    decrease
  71. Output voltage of solar photovoltaic cell would _______ if the temperature of the cell is increased
    decrease
  72. Output current of solar photovoltaic cell would _______ if the temperature of the cell is increased
    increases
  73. The power output level of a solar photovoltaic array would _______ (increase/decrease/stay the same) with increasing age.
    decrease
  74. Photon and particle radiation decrease the output of a photovoltaic array/cell in near-Earth space approximately __% per year to as much as ___%.
    5% to 35%
  75. Photovoltaic arrays are useful for spacecraft power sources to approximately ____ AU
    1.52
  76. Voltage from solar cells is increased from a fraction of a volt to tens or hundreds of volts using a _____ circuit connection
    series
  77. Current from solar cells is increased from small values (milliamps) to large current values (tens of amps) using a ______ circuit connection
    parallel
  78. The maximum power available from a photovoltaic array is found at on the voltage current output plot at a point called the ___.
    MPP
  79. The solar power available per unit area at 1 AU is approximately ______ W/m2.
    1,340
  80. The solar power available per unit area at 2 AU is approximately ____ W/m2
    335
  81. Rechargeable batteries are used for a spacecraft ______ power supply
    secondary
  82. Total battery capacity is measured in ___-hrs
    amp
  83. The percentage of a rechargeable battery's power that is available for use in a discharge cycle is called the ____ of ______.
    depth of discharge
  84. A battery's depth of discharge
    will ______ (increase/decrease/stay the same) with increasing age.
    decrease
  85. The two types of nuclear power systems used for space missions are the nuclear _____ and the nuclear ________ power.
    reactors and radioisotope power
  86. Radioisotope thermoelectric generator (RTG) electrical power sources are classified as nuclear _________ power sources
    thermoelectric
  87. Radioisotopes used in spacecraft RTGs have a fixed half-____
    life
  88. The most common radioisotope used in spacecraft RTG power sources is ______.
    238 PU
  89. Nuclear reactor power sources employ a type of radioisotopes called _________
    fissionable
  90. Nuclear electrical power supplies are used for missions roughly beyond __ AU.
    2
  91. A RTG powered by the 238Pu isotope generates ______ ______ gas as part of its decay radiation
    ionized helium
  92. A RTG converts heat into electrical power by the ________ (Seebeck) process
    thermoelectric
  93. It is possible to heat or cool using the reverse process of the Seebeck effect, called the _____ effect.
    Peltier
  94. SNAP- ____ was NASA's prototype nuclear reactor that was to be used for deep-space missions.
    100
  95. Apollo missions used the SNAP-___ for
    lunar surface experiment power sources
    27
  96. The Stirling, Rankine, and Brayton engines can be used for _____ to _____ dynamic spacecraft power.
    thermal-to-electric
  97. A conductive _____ was used to test the generation of electrical power during two Space Shuttle mission flights
    tethers
  98. Fuel cells would be used on ______ space
    flight missions since they produce ____
    • manned
    • water
  99. The Space Shuttle Orbiter's fuel cells use ______ and ______ as reactants.
    hydrogen and oxygen
  100. DC voltage from a power source is converted to a lower or a higher DC voltage using a/an _______ ______.
    electronic circuit
  101. DC voltage converted to an alternating current (AC) voltage using a/an ______
    inverter
  102. AC voltage is converted into DC voltage using a/an ______.
    rectifier
  103. The three measures of propulsion system performance are ____, _______, and _______.
    Thrust, duration, and efficiency
  104. The two sources of thrust from a rocket motor are _____ and ______.
    mass flow rate and velocity
  105. Thrust times ______ is equivalent to propulsion energy
    distance
  106. The optimum latitude for launch from the Earth's surface is ___deg
    0
  107. Specific impulse.is the ratio of _____ ______ to _____.
    thrust produced to fuel flow rate
  108. The two forces that require additional delta V to reach orbit from Earth's surface (in addition to
    acceleration needed for orbital velocity) are ____ and ______.
    g and Isp
  109. The typical value for the combined delta V required for orbit entry due to gravity and drag is ____ m/s.
    9500
  110. The two types of propulsion systems that have sufficient thrust for launching payloads into low-Earth orbit are ____ fuel systems and ___fuel systems
    liquid propellant and 3 stage rocket
  111. Multi-stage solid fuel rockets are capable of placing only _____ mass objects in orbit
    small
  112. Liquid monopropellant propulsion systems are used primary for _____ ______.
    attitude control
  113. Cold gas propulsion systems are used primarily for ________ control
    high altitude
  114. _______ is the most efficient fuel for a chemical rocket motor
    liquid hydrogen
  115. Hypergolic fuel requires no_____ _______.
    ignition system
  116. List three ways that liquid fuels can be fed from a tank in zero gravity conditions
    • capillary device
    • diaphragm
    • bellows
  117. _____ oscillations occur when a long column or long tank of dense fuel/oxidizer is accelerated
    vertically.
    Pogo
  118. Exhaust flow through the convergent section of a chemical rocket exhaust nozzle must be _______, while the flow through the divergent section must be ________.
    • subsonic
    • supersonic
  119. The approximate delta V for launch to LEO is ____ m/s.
    7750
  120. The approximate delta V for launch to lunar impact is ____ m/s
    12,500
  121. The approximate delta V for launch to reach Jupiter is _____m/s
    13,930
  122. The approximate delta V for launch to reach the Sun is _____m/s.
    30,450
  123. A type II orbit has an trajectory angle that ranges from ____ deg to ____ deg
    180 to 360
  124. The shortest flight time to Mars or any other planet is with a Type __ transfer
    1
  125. Use the pork chop plot in Figure 6 of the propulsion notes to estimate the ______ C3 energy and its associated flight time from Earth to Mars in 2007
    minimum
  126. A hybrid propulsion system
    consists of a solid  _________ and a liquid ___________.
    • fuel 
    • oxidizer
  127. The most commonly used oxidizer used in liquid propellant rocket engines is ________.
    liquid oxygen
  128. Regenerative ____________ is used to reduce the extreme temperatures in liquid fuel combustion chambers and nozzles
    cooling
  129. The liquid fuel with the lowest cryogenic temperature is liquid _______.
    oxygen
  130. Although fluorine offers a higher specific impulse as an oxidizer than oxygen it is not used because ______ and ______.
    corrosive and toxic
  131. Solid rocket motors have three primary advantages over liquid propellant engines, which are:
    • long term stability 
    • No need for cryogenic storage
  132. The most common fuel component in solid rockets is powdered ________.
    aluminum
  133. Three examples of large commercial solid rocket motors are ______, _______, and_____.
    delta GEMS, titan 3, and arianne V's
  134. Heating cold gas for propulsion increases the engine's ____ impulse.
    specific
  135. A resistojet thruster is an
    example of ______ propulsion.
    electric
  136. The primary disadvantage to
    nuclear propulsion is ________.
    by products
  137. ______  is the optimum fuel (not heat source) for nuclear propulsion
    Plutonium
  138. _____ region of the solar system can be reached with solar sailing craft
    sun
  139. Positive ions ejected from an ion engine must be neutralized to avoid ____________.
    returning
  140. A Hall thruster takes advantage of both ______ and _______ fields for accelerating ion away from the engine
    magnetic and electric
  141. Several nuclear propulsion engine prototypes were developed under the name ______.
    nerva
  142. Launcher used to place payloads into Earth orbit typically have ___ to ___ stages.
    3 to 4
  143. The rule of thumb that applies to staging with respect to Isp is ______stages with high Isp should be above stages with lower____.
    • higher 
    • Isp
  144. The rule of thumb that applies to staging with respect to delta V is ______________________.
    more delta v should be provided by stages with higher Isp
  145. The rule of thumb that applies to staging with respect to mass is _____________________
    each succeeding stage mass should be smaller than its processor

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