Glossary — D
15 terms
Docking
The act of physically joining two spacecraft in orbit.
Example: Crew transfer followed a successful docking.
Dynamic pressure
The ram pressure from airspeed and density acting on a vehicle.
Example: Dynamic pressure peaks as speed rises before the air thins.
Delta-V
The total change in velocity required for an orbital maneuver or trajectory, expressing the propellant need of a mission.
Example: Mission planners budget delta-v to travel from low Earth orbit to the Moon.
Docking port
The physical interface where two spacecraft connect to transfer crew or cargo.
Example: The cargo craft berthed to the station's docking port.
Descending node
The point where an orbit crosses the reference plane moving from north to south.
Example: Reconnaissance passes often target imaging at the descending node.
Desaturation
Reducing accumulated angular momentum in reaction wheels.
Example: Wheel desaturation used magnetorquers over several orbits.
Deep throttling
Reducing thrust to a very low fraction for delicate maneuvers like landing.
Example: Deep throttling let the booster slow for a propulsive landing.
Deorbit mission
A mission ending a satellite's life by controlled reentry.
Example: A deorbit burn disposed of the retired satellite safely.
Deceleration
A reduction in velocity, often severe during entry.
Example: The crew experienced several g of deceleration during reentry.
Deployable structure
A structure that unfolds or extends after launch, such as panels or booms.
Example: Antenna deployment was commanded after the burn completed.
Deep space mission
A mission traveling far beyond Earth's orbit.
Example: Deep space missions communicate through large antennas.
Drogue chute
A small chute deployed first to stabilize and slow before the main.
Example: Drogue chutes stabilized the capsule before main deployment.
Downrange
The direction along the ground track away from the launch site.
Example: The booster landed downrange on a drone ship.
Deep space probe
A spacecraft designed to travel far beyond Earth's orbit.
Example: The deep space probe returned the first close images of Pluto.
Decommissioning
The final phase retiring a spacecraft and disposing it safely.
Example: The spacecraft performed its end-of-life deorbit and burned up.