200 ERAU exam #1 prep cards

SOI

Sphere of Influence

ISS

International Space Station

ECO

Engine Cut-off

Isp

Specific Impulse (a metric defining propulsive efficiency)

TCS

Thermal Control System

PTCS

Passive Thermal Control System

ATCS

Active Thermal Control System

IATCS

Internal Active Thermal Control System

EATCS

External Active Thermal Control System

IFHX

Interface Heat Exchanger

EPS

Electrical Power System

PVA

Photovoltaic Array

SAW

Solar Array Wing

SARJ

Solar Alpha Rotary Joint

LOR

Lunar Orbit Rendezvous

CM

Command Module

SM

Service Module

LM

Lunar Module

LRV

Lunar Roving Vehicle

SDA

Space Domain Awareness

ISR

Intelligence, Surveillance, and Reconnaissance

ASAT

Anti-Satellite weapon system

KKV

Kinetic Kill Vehicle

EKV

Exoatmospheric Kill Vehicle

DEW

Directed Energy Weapon

KOS

Keep Out Sphere

DCS

Decompression Sickness ("the bends")

EMU

Extravehicular Mobility Unit (U.S. spacesuit)

EVA

Extravehicular Activity (spacewalk)

FGB

Functional Cargo Block (Russian: Funktsionalno-Gruzovoy Blok)

What is the outward order of the major components of our Solar System?

Sun → Terrestrial Planets → Asteroid Belt → Gas & Ice Giants → Kuiper Belt

Which four planets are classified as Terrestrial (Inner) planets?

Mercury, Venus, Earth, and Mars

Which four planets are classified as Gas & Ice (Outer) giants?

Jupiter, Saturn, Uranus, and Neptune

What are Kepler's Laws of Planetary Motion?

The foundational gravitational laws that dictate orbital paths and the mechanics of all celestial bodies and artificial satellites

Define orbital Perigee.

The unique orbital location where an artificial satellite or spacecraft reaches its closest approach to the Earth

Define orbital Apogee.

The unique orbital location where an artificial satellite or spacecraft reaches its furthest distance from the Earth

What is Escape Velocity?

The minimum speed required for a non-propelled object to permanently break free from the gravitational pull of a primary celestial body

What is the Sphere of Influence (SOI) in orbital mechanics?

The specific spherical region around a planet inside which its gravitational forces dominate the path of an object relative to a larger body like the Sun

What is a Hohmann Transfer Orbit?

An efficient orbital maneuver that uses an elliptical path to transfer a satellite or spacecraft between two circular orbits of different altitudes

How many propulsive engine burns are typically required to complete a Hohmann Transfer?

Two precise propulsive engine burns

What is a Spiral Transfer?

A low-thrust, slow, continuous propulsion method utilized to expand an orbital altitude incrementally over time

Define Direct Insertion trajectory.

A launch trajectory that places a payload directly into its final target orbit or interplanetary path without using a temporary parking orbit

What is a Gravity Assist (G-Assist)?

Utilizing the relative orbital velocity and gravity of a planet or moon to intentionally change the speed and vector of a spacecraft without consuming propellant

Describe a Molniya Orbit.

A highly eccentric, high-inclination orbit engineered to maximize time over high-latitude polar regions

What is the primary operational application for a Molniya Orbit?

Commercially and militarily ideal for communication satellites serving high-latitude regions

What was the primary destination of the robotic flagship mission Cassini?

Deep exploration of Saturn, its planetary ring structure, and its extensive moon system

What historic milestone did the New Horizons mission achieve?

Performed the world's first close-range flyby of Pluto and continues to explore the Kuiper Belt

What is the core optimization of the James Webb Space Telescope (JWST)?

A premier deep-space astronomical observatory optimized for high-sensitivity infrared imaging

What is the primary scientific mission of the Perseverance rover?

Explores Mars to search for astrobiological signs and extract physical core samples for future retrieval

What is the orbital period of the planet Mercury?

Approximately 88 Earth days

What happens to a spacecraft's speed at orbital apogee?

It reaches its minimum orbital velocity before accelerating back toward perigee.

What happens to a spacecraft's speed at orbital perigee?

It reaches its maximum orbital velocity before slowing back down toward apogee.

Why are launch windows critical for interplanetary transfers?

They align the departure planet and destination planet to allow for the lowest energy trajectory (like a Hohmann transfer)

What defines a highly eccentric orbit?

An orbit with a stretched, elongated elliptical shape, where the eccentricity value approaches 1.

What parameter determines the tilt of a spacecraft's orbit relative to the Earth's equator?

Orbital Inclination.

What are the four core systems of a rocket?

Structural System, Propulsion System, Payload System, and Guidance System

Define the Structural System of a rocket.

The strong, lightweight frame, outer skin, and fairings that structurally contain and protect the launch vehicle

What components are included in a rocket's Propulsion System?

Rocket engines, propellant tanks, plumbing, and valves required to deliver thrust

Define the Payload System of a launch vehicle.

The exact cargo, satellite, scientific spacecraft, or crew capsule intended to be carried into orbit

What components comprise a rocket's Guidance System?

Integrated computers, sensors, gyroscopes, and software that actively track and steer the rocket along its planned trajectory

What is the sequential order of the four primary flight phases of a rocket?

Launch → Powered Flight → Staging → Engine Cut-off (ECO)

What does Specific Impulse (Isp) measure?

The foundational engineering metric defining the propulsive efficiency of an engine (thrust delivered per unit weight flow rate of propellant consumed)

What mechanisms are used in a Passive Thermal Control System (PTCS)?

Operates without fluid loops or active electrical routing, using Multi-Layer Insulation (MLI), special paints/coatings, solar sunshields, heat pipes, or mechanical louvers

What elements characterize an Active Thermal Control System (ATCS)?

Relies on actively pumped fluid loops, mechanical cold-plates, pumps, and heat exchangers to route internal heat to external rejectors

What specific fluid circulates inside the ISS Internal Active Thermal Control System (IATCS)?

Water (chosen to safely capture heat inside crew cabins without exposing them to toxic chemicals)

What fluid circulates inside the ISS External Active Thermal Control System (EATCS)?

Anhydrous ammonia (chosen for its high thermal capacity and ultra-low freezing point)

What is the freezing point of anhydrous ammonia used in space radiators?

-107°F / -77°C

What hardware component bridges the internal water loops and external ammonia loops of the ISS?

Interface Heat Exchanger (IFHX)

What are the core functions of a spacecraft's Electrical Power System (EPS)?

Energy collection, conversion, management, and distribution across all spacecraft components

How is the ISS solar configuration structured?

Employs Photovoltaic Arrays organized as 8 Solar Array Wings (SAWs) split across 4 distinct matching sets

What is the total power output range generated by the ISS Solar Array Wings?

84 to 120 kW

What is the role of the Solar Alpha Rotary Joint (SARJ)?

The essential mechanized tracking gimbal that continuously rotates the massive outer truss segments to ensure the solar wings track the Sun perfectly

What type of batteries are currently used to maintain ISS power during an eclipse?

High-efficiency Lithium-Ion batteries

How long does the eclipse period last during each ISS orbit?

Exactly 30 minutes

What is the total length of one full ISS orbit?

92.65 minutes

What is the primary engineering advantage of a liquid propellant rocket engine?

Liquid engines can be throttled, shut down, and restarted mid-flight, allowing for high precision control.

What is the primary disadvantage of a solid propellant rocket engine?

Once ignited, a solid rocket motor cannot be actively shut down or throttled; it burns continuously until fuel is exhausted.

Describe a hybrid rocket engine design.

A propulsive design utilizing propellant components in two different phases, typically a solid fuel core paired with a liquid or gaseous oxidizer.

What does Multi-Layer Insulation (MLI) protect against?

Radiative heat transfer in the vacuum of space, appearing as the shiny gold or silver crinkled blankets covering spacecraft.

What is the role of mechanical louvers in a spacecraft's passive thermal design?

They open or close automatically to vary the rate of heat radiation from the spacecraft's internal components into open space.

What were the core objectives of NASA's Project Mercury?

Establish a human spacecraft safely in Earth orbit, evaluate human performance and physiological survival in microgravity, and recover both capsule and crew safely

Which launch vehicle was utilized for early suborbital Project Mercury flights?

Redstone rocket (e.g., Alan Shepard's flight)

Which launch vehicle was introduced for full orbital Project Mercury flights?

Atlas rocket (e.g., John Glenn's flight)

Who was the first American astronaut to cross into space?

Alan Shepard (on a suborbital Redstone flight)

Who was the first American astronaut to successfully orbit the Earth?

John Glenn (aboard Friendship 7)

What were the primary operational goals of Project Gemini?

Double crew capacity to 2 people, extend orbital duration up to 14 days, perfect orbital rendezvous and docking techniques, execute EVAs, and validate controlled re-entries

What heavy launch vehicle was utilized for all crewed Project Gemini missions?

Titan II rocket

What historic milestone was achieved during the Gemini IV mission?

Ed White completed the historic first American spacewalk (EVA)

Who were the crew members of the historic Gemini VIII mission?

Neil Armstrong and David Scott

What world-first milestone was successfully achieved by Gemini VIII?

Completed the world's first successful space rendezvous and docking with an uncrewed target vehicle

What was the name of the uncrewed target vehicle docked with during Gemini VIII?

Agena target vehicle

What critical mechanical malfunction occurred shortly after docking on Gemini VIII?

A stuck attitude control thruster caused the combined spacecraft to enter a dangerous, accelerating roll

How did Neil Armstrong safely save the Gemini VIII spacecraft and crew?

Undocked from the Agena and activated the capsule's Re-entry Control System (RCS) thrusters to counteract the spin, forcing an immediate emergency re-entry

What environmental upgrade did Gemini have over Mercury to support 14-day flights?

Introduction of fuel cells for long-duration electrical power and improved life support loops.

Why was perfecting rendezvous and docking in Gemini critical for NASA's future?

It was an absolute requirement to validate the Lunar Orbit Rendezvous profile planned for the Apollo moon landings.

What flight profile did NASA engineers select to execute the moon landing missions?

Lunar Orbit Rendezvous (LOR)

Why was Lunar Orbit Rendezvous chosen over Direct Insertion or Earth Orbit Assembly?

It saved immense vehicle mass and fuel by utilizing a separate, ultra-lightweight dedicated landing module

What primary heavy-lift launch vehicle was developed for the Apollo program?

Saturn V rocket

What three distinct spacecraft components comprised the Apollo flight stack?

Command Module (CM), Service Module (SM), and Lunar Module (LM)

What are the two independent stages of the Apollo Lunar Module? | Descent Stage (used to land on the moon) and Ascent Stage (used to blast off from the moon)