Spacecraft Systems exam 2

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  1. The heart of a digital computer is the _____ processor unit
  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
  7. Spacecraft are protected from all but the most extreme radiation damage by a process called
    radiation _______.
  8. Spacecraft Command and Data Handling (C&DH) system reconfiguration is necessary for to provide ____ and/or ____ recovery and future ________.
  9. _______ is needed in spacecraft C&DH systems to avoid catastrophic errors and component failures
  10. _____ is the term commonly used for measuring the computing speed or power for a computing system.
  11. The highest-order control on a digital command and data system is called _______ control
  12. The first manned spacecraft outfitted with a digital command and data-handling system was the ______ capsule.
  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
  16. The first manned program to use a triple-redundant digital processing system and validation voting was the ______ program
  17. The Space Shuttle Digital Processing System
    incorporates ___ separate General Purpose Computers
  18. The Space Shuttle Digital Processing System has ___ entirely independent sets of operating software.
  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
  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 _______
  24. Multiple sensor signals converted to serial information for transfer through the communications system is accomplished by the use of a ________
  25. Mixed data on a serial line can be converted to parallel destination lines by using a _______
  26. The basic modulation process combines the data signal with the carrier signal at the ____ frequency to allow transmission at the proper transmission frequency.
  27. The gain of an antenna increases or decreases with operating frequency (f) by a factor of f ______
  28. The gain of an antenna increases or decreases with the antenna diameter (d) by a factor of d ______
  29. Is there a gain difference for an antenna that used for transmitting signals and the same
    antenna used for receiving signals?
  30. Is there a difference in the beam width for an antenna used for transmitting and the same antenna used for receiving?
  31. Communications system receivers often experience interference signals (noise) through the antenna ______
  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 _____
  34. A/an _____ antenna is used as a standard to measure or compare other antenna types.
  35. The central frequency of a communications signal is _______ if the spacecraft is moving away from the ground station.
  36. The central frequency of a communications signal is _______ if the spacecraft is moving towards the ground station
  37. A linear vertical antenna receives ___
    of the signal from a linear horizontal polarized transmitted signal.
  38. A linear horizontal antenna receives ___ of
    the signal from right circular polarized transmitted signal.
  39. The bandwidth of a communications system is typically defined as the signal width measured inside ___ of the maximum (peak) power
  40. The dB value corresponding to a power (ratio) gain of 10,000 is ___ dB
  41. The power ratio corresponding to a gain of 3.45 dB is _____
  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
  45. Spacecraft communications systems use _____ ______Modulation
    Pulse Code
  46. The Project Mercury capsule
    had a total of ____ separate telemetry data parameters
  47. The first manned spacecraft to use digital telemetry was _____
  48. The Apollo Command Module used a total of ____ telemetry instrument parameters
  49. The International Space Station has more than ________ telemetry instrument parameters
  50. NASA's four primary Ground Network (GN) installations are the ____, the _____, the ____, and the ____.
  51. NASA's Space Net includes the ______ network.
  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 ____
  54. The Deep-Space Network includes network antenna facilities at __ sites around the world
  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.
  58. TDRSS communications are available for spacecraft in ____-Earth orbit.
  59. The _______ provides highly reliable communications with secure access to protect the space assets of the U.S.
  60. NASA's ____ provides links between NASA headquarters, NASA installations, remote facilities, contractor facilities, and universities
  61. Quantization error would be ________ if
    the data resolution (number of signal levels) in a data system were decreased.
  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
  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 ______.
  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.
  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).
  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.
  70. Output power of solar photovoltaic cell would ________ (increase/decrease/stay the same) if the temperature of the cell is increased
  71. Output voltage of solar photovoltaic cell would _______ if the temperature of the cell is increased
  72. Output current of solar photovoltaic cell would _______ if the temperature of the cell is increased
  73. The power output level of a solar photovoltaic array would _______ (increase/decrease/stay the same) with increasing age.
  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
  76. Voltage from solar cells is increased from a fraction of a volt to tens or hundreds of volts using a _____ circuit connection
  77. Current from solar cells is increased from small values (milliamps) to large current values (tens of amps) using a ______ circuit connection
  78. The maximum power available from a photovoltaic array is found at on the voltage current output plot at a point called the ___.
  79. The solar power available per unit area at 1 AU is approximately ______ W/m2.
  80. The solar power available per unit area at 2 AU is approximately ____ W/m2
  81. Rechargeable batteries are used for a spacecraft ______ power supply
  82. Total battery capacity is measured in ___-hrs
  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.
  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
  87. Radioisotopes used in spacecraft RTGs have a fixed half-____
  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 _________
  90. Nuclear electrical power supplies are used for missions roughly beyond __ AU.
  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
  93. It is possible to heat or cool using the reverse process of the Seebeck effect, called the _____ effect.
  94. SNAP- ____ was NASA's prototype nuclear reactor that was to be used for deep-space missions.
  95. Apollo missions used the SNAP-___ for
    lunar surface experiment power sources
  96. The Stirling, Rankine, and Brayton engines can be used for _____ to _____ dynamic spacecraft power.
  97. A conductive _____ was used to test the generation of electrical power during two Space Shuttle mission flights
  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 ______
  102. AC voltage is converted into DC voltage using a/an ______.
  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
  106. The optimum latitude for launch from the Earth's surface is ___deg
  107. Specific 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.
  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
  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
  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.
  120. The approximate delta V for launch to lunar impact is ____ m/s
  121. The approximate delta V for launch to reach Jupiter is _____m/s
  122. The approximate delta V for launch to reach the Sun is _____m/s.
  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
  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
  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
  129. The liquid fuel with the lowest cryogenic temperature is liquid _______.
  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 ________.
  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.
  135. A resistojet thruster is an
    example of ______ propulsion.
  136. The primary disadvantage to
    nuclear propulsion is ________.
    by products
  137. ______  is the optimum fuel (not heat source) for nuclear propulsion
  138. _____ region of the solar system can be reached with solar sailing craft
  139. Positive ions ejected from an ion engine must be neutralized to avoid ____________.
  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 ______.
  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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Spacecraft Systems exam 2
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