// ORBITAL LOGISTICS AND PROPULSION TERM
Mission Elapsed Time
Mission Elapsed Time (MET) is a clock that starts at the moment of liftoff and continuously counts up, providing a universal time reference for all mission activities.
TECHNICAL DEFINITION
Mission Elapsed Time (MET) is a continuous chronological counter that begins at the precise moment of liftoff (T-0) for a space mission, serving as the primary time reference for all subsequent mission events, operations, and data logging.
BACKGROUND
The James Webb Space Telescope (JWST) is a space telescope designed to conduct infrared astronomy. It is the largest telescope in space, and is equipped with high-resolution and high-sensitivity instruments, allowing it to view objects too old, distant, or faint for the Hubble Space Telescope. This enables investigations across many fields of astronomy and cosmology, such as observation of the first stars and the formation of the first galaxies, and detailed atmospheric characterization of potentially habitable exoplanets.
READ MORE ON WIKIPEDIASYNONYMS & ALIASES
- MET
- Flight Time
- Mission Time
- Elapsed Time
USAGE NOTE
All mission events are scheduled and reported using Mission Elapsed Time.
DEVELOPERS
Organizations developing technology related to Mission Elapsed Time.
As the primary U.S. space agency, NASA plans, launches, and operates numerous space missions where Mission Elapsed Time (MET) is a fundamental metric for mission planning, real-time operations, and scientific data analysis. Their mission control centers and flight software systems are built around MET.
SpaceX designs, manufactures, and launches advanced rockets (Falcon series, Starship) and spacecraft (Dragon). MET is critical for managing launch sequences, in-orbit maneuvers, crew operations, and re-entry for both their uncrewed and crewed missions.
ESA coordinates European space efforts, conducting scientific, exploration, and operational missions. Similar to NASA, ESA relies on Mission Elapsed Time for the planning, execution, and tracking of its diverse portfolio of spacecraft and missions, from launch to end-of-life.
Boeing is a major contractor for space programs, including developing the CST-100 Starliner spacecraft, components for the International Space Station, and various satellites. Their flight systems and mission support software heavily incorporate Mission Elapsed Time.
Lockheed Martin is involved in the development and operation of numerous space systems, including satellites, interplanetary probes (e.g., Mars missions), and the Orion spacecraft. Mission Elapsed Time is a core component of their mission planning, command, and telemetry systems.
Northrop Grumman develops and manufactures launch vehicles (e.g., Antares), spacecraft (e.g., Cygnus cargo spacecraft), and various satellite systems. MET is integral to their vehicle guidance, navigation, control, and mission operations software for delivering payloads to space and resupplying the ISS.
Blue Origin is developing reusable rocket systems (New Shepard, New Glenn) and lunar landers. Mission Elapsed Time is a crucial parameter for their launch countdowns, flight profiles, spacecraft operations, and mission control during suborbital and orbital flights.
ULA operates the Atlas V, Delta IV Heavy, and upcoming Vulcan Centaur launch vehicles. MET is a fundamental aspect of their launch sequencing, mission event timing, and trajectory tracking from liftoff through payload deployment.