Spacecraft Systems exam 2
Card Set Information
Spacecraft Systems exam 2
The heart of a digital computer is the _____ processor unit
The two basic types of digital computer memory are ____ and ____
RAM and Bulk
Commands sent to a spacecraft data handling system are processed with the ________ _________
The three types of digital computer hardware topology include _____, _____, and _____
Bus, Multiplexed, andhybrid
Two types of digital computer redundancy include _______ and ______
dedicated and shared
In digital systems, _______ errors are called soft errors
Spacecraft are protected from all but the most extreme radiation damage by a process called
Spacecraft Command and Data Handling (C&DH) system reconfiguration is necessary for to provide ____ and/or ____ recovery and future ________.
_______ is needed in spacecraft C&DH systems to avoid catastrophic errors and component failures
_____ is the term commonly used for measuring the computing speed or power for a computing system.
The highest-order control on a digital command and data system is called _______ control
The first manned spacecraft outfitted with a digital command and data-handling system was the ______ capsule.
Computer designed for the ______, ______, and ______ manned programs used ferromagnetic core memory units.
Gemini, Apollo, and Space Shuttle
Both the Apollo ______ Module and the ______ Module used identical digital computer processors
Command and Lunar
The first space program to use integrated circuits (microelectronics) for its digital processing system was NASA's _____ program
The first manned program to use a triple-redundant digital processing system and validation voting was the ______ program
The Space Shuttle Digital Processing System
incorporates ___ separate General Purpose Computers
The Space Shuttle Digital Processing System has ___ entirely independent sets of operating software.
The four basic elements of the spacecraft communications system are
Data Management System
_______ communications systems have both a forward and backward (uplink and downlink) communications link
The low voltage/current signals found in many sensors are increased to digital circuit voltages by using a ______ _______
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 ______ ______
The typically weak signals received at the antenna input of a spacecraft receiver are increased in strength by a _______
Multiple sensor signals converted to serial information for transfer through the communications system is accomplished by the use of a ________
Mixed data on a serial line can be converted to parallel destination lines by using a _______
The basic modulation process combines the data signal with the carrier signal at the ____ frequency to allow transmission at the proper transmission frequency.
The gain of an antenna increases or decreases with operating frequency (f) by a factor of f ______
The gain of an antenna increases or decreases with the antenna diameter (d) by a factor of d ______
Is there a gain difference for an antenna that used for transmitting signals and the same
antenna used for receiving signals?
Is there a difference in the beam width for an antenna used for transmitting and the same antenna used for receiving?
Communications system receivers often experience interference signals (noise) through the antenna ______
The two most common types of signal modulation are ___ Modulation and _______ modulation
CW Modulation and PM-pulsemodulation
To prevent either accidental or malicious interference with spacecraft control, the uplink and downlink communications signals are _____
A/an _____ antenna is used as a standard to measure or compare other antenna types.
The central frequency of a communications signal is _______ if the spacecraft is moving away from the ground station.
The central frequency of a communications signal is _______ if the spacecraft is moving towards the ground station
A linear vertical antenna receives ___
of the signal from a linear horizontal polarized transmitted signal.
A linear horizontal antenna receives ___ of
the signal from right circular polarized transmitted signal.
The bandwidth of a communications system is typically defined as the signal width measured inside ___ of the maximum (peak) power
The dB value corresponding to a power (ratio) gain of 10,000 is ___ dB
The power ratio corresponding to a gain of 3.45 dB is _____
The three atmospheric windows are found in the _____, ______, and ______
infrared, the radio, and the microwave
S-band microwave frequencies span ___ to ___ Gigahertz (GHz).
2 to 4
A signal-to-noise ratio of ___:___ is considered
reasonable for the reliable reception of signals with a simple communications
Spacecraft communications systems use _____ ______Modulation
The Project Mercury capsule
had a total of ____ separate telemetry data parameters
The first manned spacecraft to use digital telemetry was _____
The Apollo Command Module used a total of ____ telemetry instrument parameters
The International Space Station has more than ________ telemetry instrument parameters
NASA's four primary Ground Network (GN) installations are the ____, the _____, the ____, and the ____.
DSN, STDN, WFF, WATR
NASA's Space Net includes the ______ network.
The ground station for NASA's TDRSS satellite communications network is located in ______ ______, New Mexico.
Deep-space missions are supported by NASA's ____
The Deep-Space Network includes network antenna facilities at __ sites around the world
NASA's Deep-Space Network handles __-band,
__-band, and __-band communications
NASA's TDRSS satellite network handles __-band, __-band, and __-band communications
The TDRSS ground station has __ entirely independent network facilities.
TDRSS communications are available for spacecraft in ____-Earth orbit.
The _______ provides highly reliable communications with secure access to protect the space assets of the U.S.
NASA's ____ provides links between NASA headquarters, NASA installations, remote facilities, contractor facilities, and universities
Quantization error would be ________ if
the data resolution (number of signal levels) in a data system were decreased.
What is meant by the term MIPS?
Millions of Instructions per Second- measure of the processing power and speed of the computer
The Nyquist sampling rate for a signal frequency of 12 MHz is __ MHz
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.
The lowest cost electrical power sources available for short-duration space missions at low power levels include ______.
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
The _______ principle describes the production of electrical energy from photon energy.
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).
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.
Output power of solar photovoltaic cell would ________ (increase/decrease/stay the same) if the temperature of the cell is increased
Output voltage of solar photovoltaic cell would _______ if the temperature of the cell is increased
Output current of solar photovoltaic cell would _______ if the temperature of the cell is increased
The power output level of a solar photovoltaic array would _______ (increase/decrease/stay the same) with increasing age.
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%
Photovoltaic arrays are useful for spacecraft power sources to approximately ____ AU
Voltage from solar cells is increased from a fraction of a volt to tens or hundreds of volts using a _____ circuit connection
Current from solar cells is increased from small values (milliamps) to large current values (tens of amps) using a ______ circuit connection
The maximum power available from a photovoltaic array is found at on the voltage current output plot at a point called the ___.
The solar power available per unit area at 1 AU is approximately ______ W/m2.
The solar power available per unit area at 2 AU is approximately ____ W/m2
Rechargeable batteries are used for a spacecraft ______ power supply
Total battery capacity is measured in ___-hrs
The percentage of a rechargeable battery's power that is available for use in a discharge cycle is called the ____ of ______.
depth of discharge
A battery's depth of discharge
will ______ (increase/decrease/stay the same) with increasing age.
The two types of nuclear power systems used for space missions are the nuclear _____ and the nuclear ________ power.
reactors and radioisotope power
Radioisotope thermoelectric generator (RTG) electrical power sources are classified as nuclear _________ power sources
Radioisotopes used in spacecraft RTGs have a fixed half-____
The most common radioisotope used in spacecraft RTG power sources is ______.
Nuclear reactor power sources employ a type of radioisotopes called _________
Nuclear electrical power supplies are used for missions roughly beyond __ AU.
A RTG powered by the 238Pu isotope generates ______ ______ gas as part of its decay radiation
A RTG converts heat into electrical power by the ________ (Seebeck) process
It is possible to heat or cool using the reverse process of the Seebeck effect, called the _____ effect.
SNAP- ____ was NASA's prototype nuclear reactor that was to be used for deep-space missions.
Apollo missions used the SNAP-___ for
lunar surface experiment power sources
The Stirling, Rankine, and Brayton engines can be used for _____ to _____ dynamic spacecraft power.
A conductive _____ was used to test the generation of electrical power during two Space Shuttle mission flights
Fuel cells would be used on ______ space
flight missions since they produce ____
The Space Shuttle Orbiter's fuel cells use ______ and ______ as reactants.
hydrogen and oxygen
DC voltage from a power source is converted to a lower or a higher DC voltage using a/an _______ ______.
DC voltage converted to an alternating current (AC) voltage using a/an ______
AC voltage is converted into DC voltage using a/an ______.
The three measures of propulsion system performance are ____, _______, and _______.
Thrust, duration, and efficiency
The two sources of thrust from a rocket motor are _____ and ______.
mass flow rate and velocity
Thrust times ______ is equivalent to propulsion energy
The optimum latitude for launch from the Earth's surface is ___deg
Specific impulse.is the ratio of _____ ______ to _____.
thrust produced to fuel flow rate
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
The typical value for the combined delta V required for orbit entry due to gravity and drag is ____ m/s.
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
Multi-stage solid fuel rockets are capable of placing only _____ mass objects in orbit
Liquid monopropellant propulsion systems are used primary for _____ ______.
Cold gas propulsion systems are used primarily for ________ control
_______ is the most efficient fuel for a chemical rocket motor
Hypergolic fuel requires no_____ _______.
List three ways that liquid fuels can be fed from a tank in zero gravity conditions
_____ oscillations occur when a long column or long tank of dense fuel/oxidizer is accelerated
Exhaust flow through the convergent section of a chemical rocket exhaust nozzle must be _______, while the flow through the divergent section must be ________.
The approximate delta V for launch to LEO is ____ m/s.
The approximate delta V for launch to lunar impact is ____ m/s
The approximate delta V for launch to reach Jupiter is _____m/s
The approximate delta V for launch to reach the Sun is _____m/s.
A type II orbit has an trajectory angle that ranges from ____ deg to ____ deg
180 to 360
The shortest flight time to Mars or any other planet is with a Type __ transfer
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
A hybrid propulsion system
consists of a solid _________ and a liquid ___________.
The most commonly used oxidizer used in liquid propellant rocket engines is ________.
Regenerative ____________ is used to reduce the extreme temperatures in liquid fuel combustion chambers and nozzles
The liquid fuel with the lowest cryogenic temperature is liquid _______.
Although fluorine offers a higher specific impulse as an oxidizer than oxygen it is not used because ______ and ______.
corrosive and toxic
Solid rocket motors have three primary advantages over liquid propellant engines, which are:
long term stability
No need for cryogenic storage
The most common fuel component in solid rockets is powdered ________.
Three examples of large commercial solid rocket motors are ______, _______, and_____.
delta GEMS, titan 3, and arianne V's
Heating cold gas for propulsion increases the engine's ____ impulse.
A resistojet thruster is an
example of ______ propulsion.
The primary disadvantage to
nuclear propulsion is ________.
______ is the optimum fuel (not heat source) for nuclear propulsion
_____ region of the solar system can be reached with solar sailing craft
Positive ions ejected from an ion engine must be neutralized to avoid ____________.
A Hall thruster takes advantage of both ______ and _______ fields for accelerating ion away from the engine
magnetic and electric
Several nuclear propulsion engine prototypes were developed under the name ______.
Launcher used to place payloads into Earth orbit typically have ___ to ___ stages.
3 to 4
The rule of thumb that applies to staging with respect to Isp is ______stages with high Isp should be above stages with lower____.
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
The rule of thumb that applies to staging with respect to mass is _____________________
each succeeding stage mass should be smaller than its processor