Rocket Science Fundamentals
This scientist formulated the rocket equation that bears his name in 1903, laying the foundation for modern rocketry.
What is Tsiolkovsky?
This term describes the point during a rocket launch where it's too late to abort to the launch site but still possible to achieve alternate landing.
What is "commit point" or "point of no return"?
This grain shape in solid rockets produces roughly constant thrust throughout the burn.
What is a cylindrical core/neutral grain?
The Space Shuttle's main engines used this propellant combination.
What is liquid hydrogen and liquid oxygen?
This term describes the imaginary boundary where Earth's gravitational influence is balanced by the Sun's.
What is the Hill sphere?
In rocket science, this term refers to the ratio of exhaust speed to the amount of propellant used.
What is specific impulse (Isp)?
ATTACK! This launch location offers the greatest velocity boost from Earth's rotation.
What is the equator?
This element is cooled to -253°C to create the liquid hydrogen used in high-performance rocket engines.
What is hydrogen?
This technique uses a planet's atmosphere to slow a spacecraft without using propellant.
What is aerobraking?
This orbit allows a satellite to remain over the same spot on Earth's equator.
What is a geostationary orbit?
The shape of this component of a rocket engine is designed to convert high-pressure, low-velocity gas flow into low-pressure, high-velocity flow.
What is a De Laval nozzle?
This maneuver involves turning the rocket to align with its orbital trajectory after clearing the launch pad.
What is a gravity turn?
This type of rocket engine uses gasified propellants and no turbopumps to deliver moderate performance with mechanical simplicity.
What is a pressure-fed engine?
ATTACK! This strategic technique uses planetary gravitational fields to accelerate a spacecraft without using propellant.
What is gravity assist/slingshot?
This unique class of orbit follows figure-eight patterns and can be useful for communications with polar regions.
What is a Molniya orbit?
This term describes the phenomenon where a rocket's propellant shifts within the tank during acceleration changes, potentially causing stability issues.
What is propellant sloshing?
This path taken by rockets to minimize aerodynamic stress and optimize fuel efficiency is named after its characteristic shape.
What is a dog-leg trajectory?
This material is commonly used in modern solid rocket motor casings to save weight compared to steel.
What is carbon fiber composite?
This term describes the use of resources found at the destination to produce propellant for the return journey.
What is in-situ resource utilization (ISRU)?
This point between Earth and the Moon is where gravitational forces cancel out, allowing spacecraft to "park" with minimal station-keeping.
What is Lagrange point L1?
This cycle used in liquid rocket engines pre-burns a portion of the propellant to drive the turbopumps before the main combustion.
What is a staged combustion cycle?
This zone in rocket design represents the compromise between aerodynamic drag at lower altitudes and gravity losses at higher altitudes.
What is the gravity drag optimal ascent profile?
This state of matter in rocket nozzles occurs when propellant molecules partially dissociate due to extreme heat.
What is plasma?
This spacecraft propulsion concept uses solar-heated hydrogen as propellant to achieve high efficiency.
What is a solar thermal rocket?
This mathematical concept allows mission planners to identify low-energy transfer paths between various orbits.
What is the Interplanetary Transport Network (or Weak Stability Boundary theory)?