Delta-vDelta-v (also known as "change in velocity"), symbolized as Δv{\textstyle {\Delta v}} and pronounced /dɛltəviː/, as used in spacecraft flight dynamics, is a measure of the impulse per unit of spacecraft mass that is needed to perform a maneuver such as launching from or landing on a planet or moon, or an in-space orbital maneuver. It is a scalar that has the units of speed. As used in this context, it is not the same as the physical change in velocity of said spacecraft.
CyclerA cycler is a potential spacecraft on a closed transfer orbit that would pass close to two celestial bodies at regular intervals. Cyclers could be used for carrying heavy supplies, life support and radiation shielding.
SpacecraftA spacecraft is a vehicle that is designed to fly and operate in outer space. Spacecraft are used for a variety of purposes, including communications, Earth observation, meteorology, navigation, space colonization, planetary exploration, and transportation of humans and cargo. All spacecraft except single-stage-to-orbit vehicles cannot get into space on their own, and require a launch vehicle (carrier rocket).
Spacecraft propulsionMethod used to accelerate spacecraft
TrajectoryA trajectory is the path an object takes through its motion over time. In classical mechanics, a trajectory is defined by Hamiltonian mechanics via canonical coordinates; hence, a complete trajectory is defined by position and momentum, simultaneously. The object as a mass might be a projectile or a satellite. For example, it can be an orbit — the path of a planet, asteroid, or comet as it travels around a central mass.
Three-body problemIn physics, specifically classical mechanics, the three-body problem is to take the initial positions and velocities (or momenta) of three point masses orbiting each other in space and then to calculate their subsequent trajectories using Newton's laws of motion and Newton's law of universal gravitation. Unlike the two-body problem, the three-body problem has no general closed-form analytic solution.
EarthThird planet from the SunSurface equivalent doserate0.274 μSv/hAbsolute magnitude (H)−3.99AtmosphereSurface pressure101.325 kPa (at sea level)Composition by volume78.08% nitrogen (dry air)20.95% oxygen (dry air)≤1% water vapor (variable)0.9340% argon0.0430% carbon dioxide0.00182% neon0.00052% helium0.00017% methane0.00011% krypton0.00006% hydrogen Source:Earth is the third planet from the Sun and the only astronomical object known to harbor life.
MoonNatural satellite orbiting EarthSurface absorbed doserate13.2 μGy/h(during lunar daytime)Surface equivalent doserate57.0 μSv/h(during lunar daytime)Apparent magnitude−2.5 to −12.9−12.74 (mean full moon)Absolute magnitude (H)0.2Angular diameter29.3 to 34.1 arcminutesAtmosphereSurface pressure10 Pa (1 picobar) (day)10 Pa (1 femtobar) (night)Composition by volumeHeArNeNaKHThe Moon is the only natural satellite of Earth.
Orbital mechanicsOrbital mechanics , astrodynamics or space dynamics is the application of ballistics and celestial mechanics to rockets, satellites, and other spacecraft. The motion of these objects is usually calculated from laws of motion and of universal gravitation derived by Isaac Newton. Astrodynamics is a core discipline within space-mission design and control.
GravityAttraction of masses and energyThe shapes of two massive galaxies in this image evolved under the effects of gravity.In physics, gravity (from Latin gravitas 'weight'), also known as gravitation or a gravitational interaction, is a fundamental interaction, which may be described as the force that draws material objects towards each other.
Primary bodyPrime astronomical designated entity within a gravitational system Motion of the Solar System's barycenter relative to the Sun A primary body – also called a central body, host body, gravitational primary, or simply primary – is the main physical body of a gravitationally bound, multi-object system. This object constitutes most of that system's mass and will generally be located near the system's barycenter.ApsisAn apsis (from Ancient Greek (hapsís)'arch, vault' (third declension); pl.apsides ) is one of the two extreme points in the orbit of a planetary body about its primary body, either the farthest point (apoapsis) or the nearest point (periapsis). The line of apsides (also called apse line, or major axis of the orbit) is the line connecting the two apsides. Apsides pertaining to orbits around different bodies have distinct names to differentiate themselves from other apsides.*As an Amazon Associate I earn from qualifying purchases.