The Finalist of Finals
What is the name given to the ground projection of a spacecraft imaging sensor pixel?
2^# - Bit (ex: if 4 data units 2^2 - Bit is displayed as 2-Bit)
Explain the basic structure of an electromagnetic wave.
3 parts- 1) Electric field oscillating as a sine wave in one direction 2) Magnetic field oscillates at right angles to the electric field. 3) Propagation occurs perpendicularly to both electric and magnetic field movements.
What is the Maximum Acceptable Risk (MAR) for radiation exposure on a NASA mission?
3%
What is the minimum number of GPS spacecraft required to accurately pinpoint a Ground Receiver location?
4
What is a Link Budget? What is its output? What factors are important in designing one?
An equation that outputs the Signal to Noise Ratio (SNR) Important factors are signal quality from transmitter, receiver and antenna and also losses from the atmosphere.
Identify the process which extracts oxygen from water on a crewed spacecraft.
Electrolysis
Explain the difference between Passive and Active remote sensing systems. Provide one example of each.
Passive: Uses reflected and emitted sensing medium (waves) to observe target Active: Produces own sensing medium (Waves) to observe target, allowing it to track time and therefore distance
Identify the substance which facilitates a chemical reaction inside a mono-propellant rocket.
catalyst
What is meant by the "Ridiculous Solution" in GPS?
There are two intersection points between 3 overlapped spheres. One of the points is always at a high altitude and can be rejected as a 'ridiculous solution'
Identify the two basic types of rockets. What are their primary energy sources?
Thermodynamic Rockets: These are the classic rockets with great performance but poor efficiency. Energy source is from the chemical reactions. Electrodynamics Rockets: These rockets have poor performance but great efficiency. The thrust is produced through electric and magnetic fields
Identify the primary consideration in choosing a spacecraft Energy Storage Device
To handle peak power demands.
Under what circumstance(s) do charged particles bounce in a magnetic field?
When entering a region of stronger magnetic field.
Explain the process which produces 'hard' X-Rays during Solar Flares
When magnetic field lines annihilate each other during a solar flare, they break apart and propel particles at the sun, releasing a 'braking energy' which is Hard X-Rays
Identify the two basic types of Imaging Scanners. Provide one prominent advantage and disadvantage for each.
WhiskBroom: Single scanning element that shifts left and right to cover area, Cheap but provide poor resolution Pushbroom: Multiple scanning elements aligned in series. This allows the scanner to stay stationary and cover the area. Expensive but provides better resolution
Define Young's Modulus. Explain the three stages of structural failure.
Young's Modulus a stress strain plot of a material used to predict failure Proportionality Limit: Stress-strain linearity fails Yield Point: Permanent deformation occurs even after stress in removed Ultimate Yield point: Applied stress produces complete failure
Define Young's Modulus. Use a stress vs strain curve to explain the three stages of structural failure
Young's Modulus is a measure of the stiffness of a material. It helps predicts a materials reaction under stresses and strains. It can be calculated using the formula on the right and the characteristic stress of the material. The three stages of structural failure are as follows: Proportionality Limit(A), Yield Point (B), and Ultimate Yield Point (C). - Proportionality Limit: Stress-strain linearity fails. Can be used to predict an appropriate safety factor of a material. - Yield Point: Permanent deformation occures even after stress is removed. Can not be reversed without heat treating and recasting material - Ultimate Yiel Point: Applied stress produces complete failure, Part Fractures
First Human in Space?
Yuri Gagarin
At which point in an elliptical orbit is the kinetic energy minimum?
apogee
Sketch the Magnetosphere. Identify 3 Important plasma regions and 3 major current systems.
http://tinypic.com/r/15z38si/8
Name the basic process that produces energy inside a chemical rocket
oxidation
Define Emissivity. What does it mean to have a Low or High Emissivity?
Efficiency with which it can radiate heat. Low emissivity is a poor radiator/ High emissivity is a good radiator
How long is a Solar Cycle?
11 Years
Explain what is meant by the "Dynamic Envelope" of a spacecraft.
14. Dynamic Envelope is the volume that the spacecraft is limited to in order to prevent damage during the spacecraft's dynamic motion (Forces: Vibration, flexing). This motion is during launch and ascent through the atmosphere.
Through what size angle does the interceptor move during a Coplanar Rendezvous?
180*
What does a closed-loop control system incorporate that an open-loop system lacks?
Feedback
Explain the difference between Geostationary and Geosynchronous orbit.
Geostationary: Orbit hovers over a point on the equator, i=0 Geosynchronous: Orbit oscillates about a point on the equator, i not 0
Define Geosynchronous Orbit. Explain how it is different from Geostationary Orbit.
Geosynchronous is when a spacecraft oscillates about a point on the equator while a geostationary orbit hovers over a point on the equator.
Name the four most common Disturbance Torques experienced by spacecraft
Gravity Gradient Torque Solar Pressure Torque Magnetic Torque Atmospheric Drag Torque
Explain how Thermoelectric Rockets work. What are they typically used for? Why?
Heat up propellant electrically through conduction and convection to enhance thrust. Used for in-space maneuvers due to their simplicity.
Explain how streamlining a Re-Entry vehicle impacts heating, acceleration and accuracy.
Heating increases Same acceleration Higher accuracy
Explain how using a shallow Re-Entry Flight Path Angle impacts heating, acceleration and accuracy.
Heating is low Acceleration decreases Lower accuracy
Is the solar wind high beta or low beta?
High Beta
Is it better to use high or low frequency electromagnetic waves to communicate with satellites?
High Frequency
What is the name given to data produced by subsystems of the Spacecraft Bus?
Housekeeping Data
Identify the type of vehicle which would use a steep re-entry flight path angle.
ICBM
Identify the dominant physical interaction in the "Open Magnetosphere" model for geomagnetic activity
Magnetic Recombination
Identify the space weather effect most responsible for the sudden degradation of solar panels
Solar Energetic Particles
When is the average solar wind faster: solar minimum or solar maximum?
Solar Minimum
Identify the dominant source for producing Internal Heat inside a spacecraft.
"Joule Heating" (Heating produced by current carrying wires, positive ions bumping)
Identify the basic output of an Attitude Control Actuator
"Torque"
Identify the principal source of pressure (i.e. thrust) for a Solar Sail
(Electromagnetic Radiation Pressure) sunlight
Name the six subsystems of the Spacecraft Bus.
1) Attitude and Orbit Control 2) Electrical Power 3) Payload 4) Propulsion 5) Environmental Control and Life Support 6) Communications and Data Handleing
Hand-sketch the magnetosphere and identify five of the important plasma regions.
1) Cusp 2) Magneto pause 3) Lobes 4) Trapping Region 5) Neural sheet Bow shock and magneto sheath regions
Identify the three dominant sources of External Heat for a spacecraft in Earth orbit.
1) Direct Solar Input (Sun) 2) Sunlight reflected by the earth (albedo) 3) Infrared emissions generated by the Earth (Earth Shine)
Identify the spectral class of the sun
1) G2V
Identify the three categories of Spacecraft Structures. Provide one example of each.
1) Primary Structure: Carries Loads and maintains spacecraft integrity, Body Structure 2) Secondary Structures: Support structures specific to payload and subsystems needs, solar panels 3) Tertiary Structures: Miscellaneous structures, electronic boxes
Explain Kepler's Laws.
1) The movement of the planets are elliptical. 2) The area covered by the arc closer to the sun contains the same area as further away in the same time period. 3) The square of the orbital period is proportional to the average distance from the sun.
1.How are Electromagnetic Waves generated? 2.What determines their frequency?
1. Accelerating charges lose energy by "Radiating" electromagnetic waves 2. The oscillation of the charge (Large Osc=small frequency, Small Osc=large frequency)
Explain what each Maxwell equation means in words.
4 Maxwell equations that explain the shape and movement of the electric and magnetic fields with respect to their sources. Gauss Law of Electricity- stationary charges produce an electric field that spreads out through space. Gauss Law of Magnetism- Magnetic field lines close back in on themselves eventually. Faraday's Law- Time-changing magnetic field produces an electric field. Maxwell-Ampere Law- magnetic fields are produced by electric currents and electric fields are produced by magnetic currents.
What is a Fuel Cell? How is a Fuel Cell different from a battery?
A Fuel Cell is a power source that converts chemical energy into electrical energy. It is different from a battery becasue it is an open system. Meaning it can be added to for continuous use.
Explain how a rocket is different from a jet engine
A Jet engine is an open system where air is inputed and accelerated to produce thrust. A rocket is completely self sustained. It must be because as the rocket rises in altitude there is less and less air.
What is a Radioisotope Thermal Generator (RTG)? How do they work? When are they typically used?
A Radioisotope Thermoelectric Generator (or RTG) converts heat that is generated by natural decay of radioactive material into electrical current. It functions by using 2 materials with very different thermoelectric properties. These material are coupled through a semi-conductor. As one of the sides is heated the difference in resistance causes free electrons to flow between the two materials, this allows the power source to last an extremely long time. They are used aboard spacecraft that are designed for long term functioning with minimal sustainment
What is Clock Bias in GPS? Why does it occur? How is it removed?
A constant time offset for spacecraft. Occurs because of imprecise positions of 3 GPS Satellites resulting in an inexact point of intersection. Corrected with a fourth spacecraft.
What is a Fuel Cell?
A fuel Cell is a device that converts chemical energy into electrical energy. They act as Open Systems that uses two very reactive chemicals. On most space systems O2/H2 are used.
Name the major system of Ionospheric Currents at low latitudes
Solar Quiet
What is a Radioisotope Thermal Generator? How do they work? When are they typically used?
A power source that converts heat generated by natural decay of radioactive material into electrical current. There are used in deep space travel because of the sources endurance and efficiency. Work: Utilizing thermometric generator A "thermocouple" is basically two materials with very different thermoelectric properties which are in electrical contact with each other (i.e. coupled). As one side of the thermocouple heats, the difference in resistance causes free electrons to flow between the two materials and produces a current
Define Remote Sensing. Provide one advantage and one disadvantage of using spacecraft for Remote Sensing.
Acquisition of information about a target material or phenomenon without making physical contact with the target Advantage - Fast and efficient Disadvantage - Lower accuracy
Provide one Advantage and one Disadvantage of using Composite Materials in spacecraft design
Advantage - light-weight Disadvantage - High cost
Identify the 3 main types of "Out-the-Window" Sensors.
Earth Sensors Sun Sensors Star Sensors
Identify the orbital element which specifics the orientation of the orbit in the orbital plane.
Argument of Perigee
Explain Kepler Orbits. State the assumptions. Describe each of the Orbital Elements.
Assume: 1) M(sat)<<<Me 2) Me concentrated at center 3) Gravity due to earth is the only force producing work 4) Earth is not moving Forms: - Circle - Ellipse - parabola - hyperbola Variables: - Eccentricity (Size, shape) - Semi major axis (Size, shape) - Inclination (orientation) - Ascending node (orientation) -Argument of paragee - True Anomaly (location of Satellite in orbit)
Distinguish "Shortwave Fadeout" and "Polar Cap Absorption". Where and why do they occur?
At low altitudes comunication losses can be attributed to "Short wave fadeout". This is due to x-rays originating from strong solar flares which strengthen the ionization at low altitudes. "Polar cap absorption" is a communication hazard due to the intense bombardment of solar energetic particles at the poles. This increases the plasma density at high altitudes
Where is the best location to fire thrusters to change the RAAN of an orbit?
At the poles
Which type of load is responsible for stretching a structure?
Axil Tension
Define Atmospheric Window
Band of electromagnetic waves for which the atmosphere is transparent
What is the name given to data produced by subsystems of the Spacecraft Bus?
Bits/Bytes
Identify the piece of spacecraft hardware used for Gravity-Gradient Stabilization
Boom
Define Magnetopause. What determines its location?
Boundary layer between shocked solar wind and Geomagnetic Plasma. Location determined when the magnetic pressure of the Magnetosphere perfectly equals the fluid pressure of the Magnetosheath.
Explain how the Space Shuttle reduced re-entry heating and acceleration but increased accuracy.
By combining shallow re-entry angle, streamlined shape and facing the underbelly of the shuttle towards Earth during re-entry created a larger thermal projection relating to less thermal stress and more accuracy.
Where did the majority of water on the space shuttle come from?
Byproduct of O2/H2 And Recycled urine
Identify the process which replaces gravity to allow convection to function inside a Heat Pipe
Capillary Action
Identify the type of material which initiates a chemical reaction inside a Monopropellant Rocket
Catalyst
What does a "Closed-Loop" control system incorporate that an "Open-Loop" system lacks?
Closed-Loop gets FEEDBACK through measurement
Explain how Electromagnetic Waves are generated. What determines their frequency?
Combination of an electric field oscillating in the x-direction sinusoidally while a magnetic field oscillates at right angles to the electric. The wave propogates at right angles and the rate at which the change oscillates determines the frequency (Small oscillation = large frequency, large oscillation = small frequency)
Identify the process which produces solar granules
Convection
Identify the three regions of the Sun's interior and explain what happens in each.
Core- Nuclear Fusion occurs. Radiative Zone- transports energy outwards via gamma radiation Convection Zone- lets out heat due to convection
Explain the difference between a Coronal Streamer and Coronal Hole
Coronal streamers are bright regions of the corona consisting of high plasma density trapped by closed loops of magnetic field. Coronal holes are dark regions of low plasma density with open magnetic field lines so plasma can escape.
Identify the primary source of charged particles in the Inner Radiation Belt
Cosmic Rays
Explain what happens to rocket exhaust gas as it moves through a de Laval Nozzle
De Laval Nozzle decreases the pressure and temperature, and significantly the speed of gas as is passes through. Once the gas has passed through it expands and speeds go from sonic (speed of sound) to supersonic
Identify the space weather effect most responsible for degrading spacecraft insulating materials.
Deep Dielectric Charging
Which type of Shock Wave is preferable during re-entry? Why?
Depends on shape of vehicle- streamlined re-entry vehicles want attached shock wave. Blunt vehicles want detached shock wave.
Explain the difference between discrete and diffuse aurora.
Discrete- brighter and more localized Diffuse- much fainter in glow
Name the dominant mechanism for ion loss in the ionosphere
Dissociative Recombination
Explain the purpose of the Power Conditioning Unit on a spacecraft.
Distributes energy housed in the supply to power the subsystems and payload of the spacecraft bus.
Explain the purpose of the Power Conditioning Unit inside a spacecraft Electrical Power Subsystem
Distributes the right amount of current and voltage to the payload and subsystems of the spacecraft bus.
Explain why the rate of LEO satellite orbit decay increases quasi-exponentially over time.
Drag causes the orbit to become more circular, lowering altitude and increasing drag, creating a cycle until the decay accelerates so much that the satellite burns up.
Under what circumstances will a charged particle bounce in a magnetic field?
During Quasi-Perpendicular contact and entering a stronger magnetic field
Name the region of the Ionosphere where electric currents flow
E-Region
Define Emissivity
Emissivity is a constant associated with a specific type of material. It defines the efficiency of a material to be able to radiate heat. Scale ranges from 0-1 with a perfect black body as the standard.
Identify the four basic components of a spacecraft Electrical Power Subsystem (EPS)
Energy Source Power Source Power Storage Power distribution system
Who was the scientist who first suggested the solar wind is supersonic?
Eugene Parker
Identify 2 space weather effects which can adversely affect spacecraft attitude control systems
Excess noise from a solar flare event. Losing control of the attitude controls system during a geomagnetic storm due to magnetopause being pushed inwards, leaving the craft to be outside the magnetosphere without a magnetic reference.
Explain the Babcock Solar Dynamo.
Explanation for sunspot activity cycle- At solar min, a N-S magnetic field exists on the solar surface. Because of different rotation rates at the poles and equator, the field is distorted from N-S to a tangled E-W This tangled mess creates connected pairs of sunspots with opposite polarity. Sunspots migrate to the equator where the leading pairs cancel each other out and the polar field reverses direction.
Identify the scientific discovery associated with the first successful US spacecraft
Explorer one discovered radiation in space, more specifically the Van Allen radiation belt
Name the first successful US Spacecraft. In what year was it launched?
Explorer-I, 1958
Explain why the Interplanetary Magnetic Field (IMF) has a spiral shape and sector structure
IMF has a spiral shape due to the radial motion of the solar wind and the azimuthal rotation of the wind Sector Structure looks like a "ballerian skirt", That is because of the suns rotation and how is warps the heliospheric current sheet. This causes the IMF to have sections that point toward the sun and others that point away.
Identify one region of the electromagnetic spectrum for which its hard to find an Atmospheric Window
Infrared
Identify which radiation belt is more dangerous to spacecraft
Inner Radiation Belt
When would one choose a wavelength to be inside or outside an Atmospheric Window
Inside - Visible Outside - Infrared
Inside flares the Electrons are energized due to the dispersion of the magnetic field. They proceed to impact with the surface of the sun and create radiation in the form of Hard X-rays.
Inside flares the Electrons are energized due to the dispersion of the magnetic field. They proceed to impact with the surface of the sun and create radiation in the form of Hard X-rays.
Explain why the North-Eastern US is particularly prone to space weather impacts on the Power Grid.
It is in the Auroral Oval where it is subjected to more frequent GICs. It also has large amounts of non-conductive igneous rock which causes the currents to flow into man-made structures, affecting the Power Grid.
Identify the dominant source of Internal Heat on a spacecraft.
Joule Heating from internal electrical systems
Write down the condition for two launch windows per day.
Latitude < Inclination
Explain what is meant by the Lead Angle in a coplanar rendezvous
Lead angle is a description of the angular movement that a target will move during a Hohmann transfer. This angle is dependent on the angular speed of the target and the flight time of the intercepter
Are solar Prominences High or Low Beta?
Low
Identify the two categories of Spacecraft Mechanisms? Provide one example of each.
Low - Cycle: Limited Use, Solar Panel Deployment High - Cycle: High use, Reaction wheels
Identify the class of Spacecraft Mechanisms that have limited use, typically soon after launch
Low-Cycle Mechanisms
Explain why sunspots are dark
Lower relative temperature created by magnetic field lines bursting through the sun's surface
What is the class of an X-ray flare with energy flux in the 1-8 Å band of 2.8 x10-2 ergs/cm2 -sec
M2
Define Interplanetary Magnetic Field. Explain why it exists. Describe its shape. Explain why it has this shape.
Magnetic field emanating from the sun out into the solar system. When the magnetic field lines become frozen by plasma they are dispersed with the solar wind and rotation of the sun in a 'ballerina skirt' pattern. Upon reaching Earth, some field lines flow above and below it resulting in a sector structure around the Earth. Each sector determines whether the field lines are flowing toward or away from the Earth.
Identify the boundary which separates the magnetosphere from the magnetosheath.
Magnetopause
Which planet visited by Viking mission?
Mars
Define Magnetohydrodynamics. How is it derived?
Mathematical description of a plasma. Derived through combination of Maxwell's Equations (electromagnetic properties) and Navier-Stokes Equations (flow properties)
When is the average Solar Wind speed faster: at solar min or max?
Minimum
Identify the spacecraft communications hardware that combines Data with the Carrier Signal
Modulator
Explain the difference between Multi-Spectral and Hyper-Spectral imaging.
Multispectral: Multiple discontinuous bands saved using filters and/or dispersion Hyperspectral: Continuous spectrum saved using dispersion (e.g. diffraction grating)
Name of spacecraft which landed on an asteroid in 2001?
NEAR
Explain the concept of a Substorm. When and why do they occur? Describe what happens during each phase.
Occurs in the magnetotail region and usually lasts about 1-3 hours. Consists of 3 phases: Growth Phase- energy from the Solar Wind/IMF is transferred and grows in the magnetotail. Expansion Phase- energy expands and explodes out in kinetic energy producing aurora at the poles on Earth. Recovery Phase- Things recover.
Identify the time during launch when "Over" Expansion in the Rocket nozzle is most likely to occur.
On Launch Pad
Identify the two important pieces of information that GPS spacecraft broadcast.
Orbit Information Time Information
Current US Crewed Space program?
Orion Program
Explain the difference between Passive and Active actuators
Passive- Operate in an open loop without feedback Active- closed loop with constant feedback
Identify one example of a Passive Thermal Actuator and one example of an Active Thermal Actuator
Passive- paint and surface coatings Active- Heaters and refrigerators
Identify one example Passive Attitude Control Actuator and one example of Active Attitude Control Actuator
Passive: Dampers Active: Thrusters
Identify the largest environmental source of GPS error.
Solar Radiation Effects
Identify the primary consideration in choosing a spacecraft Energy Storage Device
Peak Power
What region of the Sun's atmosphere do sunspots form?
Photosphere
Identify the space weather influence most responsible for producing Phantom Commands on a spacecraft
Plasma Charging
What is usually responsible for producing "Phantom Commands" on a spacecraft?
Plasma Charging
Identify the basic output provided by an Attitude Control Actuator.
Pointing or directional capability for the payload
Identify the best location to fire thrusters to change the RAAN of a circular polar orbit.
Poles
Identify the direction of thermospheric winds during high solar activity
Poles to Equator
Does photoelectric charging of spacecraft surfaces produce a positive or negative charge?
Positive
To move from low to high altitude orbit is the delta-V positive or negative?
Positive
When moving from a lower to a higher altitude orbit is the Delta-V positive or negative?
Positive
Identify the difference between Primary and Secondary Structures on a spacecraft
Primary Structures support the spacecraft's integrity directly (i.e. body structure). Secondary structures and supportive structures that help the system meet specific payload and subsystem needs (i.e support trusses, platforms, solar panels)
Explain the difference between Primary and Secondary Batteries.
Primary: Cannot be recharged and are therefore designed to provide the sole source of electrical power for a single short (e.g. manned) mission. Secondary: Rechargeable batteries designed to provide a secondary power source when solar cells are drawing no power because of solar eclipse.
What is a Hohmann Transfer? Explain the basic concept. Identify its advantages and disadvantages.
Process by which a spacecraft changes its orbit as efficiently as possible using a series of 2 Velocity-Changing burns similar to an on-ramp on a freeway. While it is highly efficient it is a very slow process.
How are Geomagnetically Induced Currents Produced? How do they effect the power grid?
Produced during geomagnetic storms when ionospheric currents produce magnetic fields. Magnetic field lines extend to the ground and produce electric fields in the ground. GICs created from the electric fields enter the power system and add an extra magnetic field to transformers, overheating it and potentially causing fires and blackouts.
Explain the difference between Prograde and Retrograde orbits
Prograde: orbit plane is within 0 to 90* from the equatorial plane. Direction is the same as the earths rotation Retrograde: Orbit plane is within 90* to 180* from the equatorial plane. Direction is opposite to earths rotation
Identify the primary consideration in choosing a spacecraft Power Source
Provide enough power to meet average demands.
Explain the basic rationale for using Dual Frequency GPS
Provides correction for the ionosphere refraction
What shock is messier: Quasi-Parallel or Quasi-Perpendicular?
Quasi-Parallel
Identify the only method of Heat Transfer that can be used to remove excess heat from a spacecraft.
Radiation
Define "scintillation". What produces it? What are its effects? Where is it most likely to occur?
Rapid variations in the amplitude and phase of radio waves while they pass through the ionosphere and between the satellite and the ground, producing noise. Produced by small-scale plasma irregularity in the ionosphere and effects both radio wave communication and navigation, fading and losing signals and producing noise. Most likely to occur during solar maximum during geomagnetic storms, high latitudes and on the nightside of Earth.
Explain the concept of Plasma Beta. What is the distinction between High and Low Beta?
Ratio of fluid pressure to magnetic pressure inside the plasma and used to distinguish gas pressure from magnetic pressure. High Beta = more fluid-like plasma. Low Beta = more electromagnetic plasma.
Explain the configuration of the Region-1 field-aligned currents and identify what drives them
Region 1 FAC is the inner ring of the FAC, the bar like magnetic field configuration is driven by solar wind
Name the field-aligned current (FAC) system connected to the partial ring current.
Region 2 FAC
What is the name given for vibration of a structure at its Natural Frequency?
Resonance
Define Resonance and explain why it needs to be avoided in spacecraft design.
Resonance in a phenomenon that occurs when a systems operating frequency matches the natural frequency of a system. This causes large excitement in the system and can produce failure.
Identify the dataset the Space Weather Prediction Center uses to classify Solar Radiation Storms
S1-S5 from GOES
Identify the output of a "Link Budget"
SNR
Type of rocket used by Apollo-11 mission?
Saturn V
Define and distinguish Sensors and Actuators.
Sensors: Enable a closed loop to squire feedback Actuators: adjust the state of either loop
What are the typical Re-Entry design specifications for a Crewed Vehicle?
Shallow re-entry angle Withstand extended exposure to lower level heating
Explain "Shortwave Fadeout" and "Polar Cap Absorption". Where and when does each occur? How and why?
Shortwave Fadeout occurs at lower latitudes on the dayside where X-Rays expand the D-Region and cause HF Signal Fadeout for communications. Polar Cap Absorption occurs at the poles where Solar Energetic Particles are allowed to penetrate. It absorbs particles into the D-Region causing radio blackouts and scrambles communications with satellites.
Name the Single Event Effect (SEE) which is non-recoverable
Single Event Latchup
Identify the primary heat source for the stratosphere.
Solar EUV Emissions absorbed by the Ozone Layer and increases with altitude.
Explain the basic configuration and operation of a Solar Cell.
Solar cells are constructed from thin wafers of semiconductor material which have been "doped" positive (P-type) or negative (N-type). Left alone, a P-N junction is marginally stable.However, when solar electromagnetic radiation (i.e. photons) strike the cell, their energy is absorbed and electrons and "holes" start to move between the layers. Creating Voltage (Power)
In which geographic region do LEO spacecraft experience most computer anomalies? Why?
South Atlantic due to South Atlantic Anomaly from Project Argus and Starfish detonations, increasing radiation levels and weakening the magnetic field.
What is the name given to the shroud which protects a spacecraft during launch?
Spacecraft Fairing
Identify the four basic types of Remote Sensing resolution.
Spatial: location of the signal Temporal: time of the signal Radiometric: strength of signal Spectral: wavelength of signal
Name the parameter used to characterize rocket efficiency.
Specific Impulse
Define Specific Mechanical Energy
Specific Mechanical energy is mechanical energy per unit mass. It is independent of mass but dependent on orbit
Name of bright jets of plasma which form at edges of supergranules?
Spicules
Explain the difference between Static Envelope and Dynamic Envelope. Why is the distinction important?
Static Envelope: Max volume that the launch pad is capible of Dynamic Envelope: The volume the rocket must fit in to avoid coming in contact with the spacecraft fairing (Nose of rocket) during the vibrations and flexing caused in passing into orbit
What are the typical Re-Entry design specifications for an Intercontinental Ballistic Missile?
Steep flight path angle Withstand high acceleration Withstand short but intense heating
What is the AE magnetic index designed to measure?
Strength of currents and associated with aurora.
What is the Spacecraft Fairing?
Structure that protects the payload from damage during launch
What is a Solar Flare? How are they produced?
Sudden spurts of intense brightness caused by electromagnetic waves. Radiation is emitted releasing energy stronger than a hundred megaton bombs. Created when a hot plasma forces magnetic loops to eject from the surface of the sun, growing until they pinch together. When opposite magnetic field lines meet they cancel each other out in magnetic reconnection, turning magnetic energy into a solar flare.
Explain how NASA monitors the long-term genetic health of its astronauts.
Takes blood samples of astronauts before and after a mission and records the accumulated radiation to log the total radiation exposure of each person.
Explain how Differential GPS works. What is a typical application?
Takes measurements from a roving receiver and compares them to simultaneous measurements at a nearby base station. Used to simultaneously provide measurements at a moving position with a known base location.
What is the name given to downlink spacecraft communications?
Telemetry
Identify the parameter used to distinguish the layers of the atmosphere
Temperature
What is the South Atlantic Anomaly?
The South Atlantic Anomaly is a hole in the magnetic protective field allowing abnormal amounts of radiation make it to earth surface.
How is carbon-dioxide removed from the air on a crewed spacecraft?
The carbon dioxide is removed from the spacecraft's atmosphere by the use of a filter. The filter utilizes lithium-hydroxide to chemically trap the carbon dioxide.
Explain how the magnetopause current is produced.
The magnetopause the boundary of the IMF influence and the earth's magnetic field. Its distance can fluctuate from earth and is partially dependent on the collisions of the solar wind. The solar wind that hits this exposed magnetic field produces a current created by protons and electrons entering the geomagnetic field and gyrating opposite direction
What is a Hohmann transfer? What are its advantages and disadvantages?
The most fuel efficient maneuver for changing the size of an orbit in the same plane. It consists of two perpendicular burns 180* from each other. Advantage: Fuel efficient Disadvantage: Slow
Explain the difference between quasi-perpendicular and quasi-parallel space plasma shocks
The non-collision shocks associated with plasmas are classified in two types: Quasi-Parallel and quasi-Perpendicular. The difference between the two shocks are the normal (the plane that the plasma makes "contact with the magnetic field) and the end result of the shock. In Quasi-Parallel (More turbulent of the two) the normal field is inclined less than 45 degrees to the magnetic field and the plasma coils around the magnetic field. In quasi-perpendicular the normal field is greater than 45 degrees and the plasma escapes the magnetic fields.
Explain what happens to rocket exhaust as it moves through a de Laval Nozzle.
The pressure and temperature both decrease while the velocity of the exhaust becomes supersonic producing thrust.
Identify the primary driver for selecting a spacecraft orbit.
The purpose and needs of the payload
Explain the purpose and basic operation of an Antenna.
The purpose is to facilitate communications, both outgoing and incoming, through the use of microwaves. The microwaves are created and imitated by oscillating magnetic currents in the antenna
Define Specific Impulse. Explain how it relates to rocket performance
The specific impules is the delta momentum per unite weight (on earth) of the propelent. This determines the efficiency of the rocket. Like mpg
Identify the process which replaces gravity to allow convection to function inside a Heat Pipe.
The use of a "Working Fluid" (The fluid evaporates and air pressure moves the air replacing gravity), Capillary Action
Identify the reference point for measuring Sidereal Time
True Point of Ares
What was Project Paperclip?
US Program- Recruitment of German Scientists and utilizing 68 captured German V2 Rockets- 1/2 used for military research, 1/2 used for scientific research of upper atmosphere.
What region of the electromagnetic spectrum is the solar output most variable?
Ultraviolet
What are the names given to Uplink and Downlink communications between a spacecraft and the ground?
Uplink: Command (CDM) Downlink: Telemetry (TLM)
Explain how a Magnetic Torquer works to change the attitude of a spacecraft
Uses Earth's geomagnetic field to produce rotation by producing an electromagnet that tries to align itself with Earth's magnetic field, thus creating torque.
How is carbon-dioxide removed from air on a manned spacecraft?
Using filters that use lithium hydroxide chemically reacts with the carbon dioxide, trapping it in the filter
Identify the only mechanism that can be used to remove excess heat from a spacecraft altogether
Via Radiation, Louvers
The wavelength 3μm is a dividing line between which two sorts of Remote Sensing information?
Wavelengths that are less than 3um tend to be emitted and reflected by targets. This makes that wave length range ideal for passive sensing
Leader of German Rocket program during WWII?
Wernher Von Braun
What is the direction of the ring current: east or west?
West
What is a Simple Plane Change maneuver? In what sense is it 'simple'?
When a spacecraft changes its orbital plane without changing its speed thus simpler than a Delta-V
At which location is "Over Expansion" of a rocket nozzle most likely to occur?
launch pad
Identify the spacecraft hardware that combines data with the Carrier Signal.
modulator
How long does it take for energy created in the Sun's core to reach the surface?
~10 Million Years
