Time, space, clock, conversion, countdown, counters, date, distance, launch window, MET, velocity, launch, liftoff, T+, T-, T plus, T minus, PDT, CST, CDT, EDT, UTC, GMT, CET, CEST
Earth date and time
UTC +1 = CET
UTC +2 = CEST
UTC = GMT = Zulu
UTC -4 = EDT
UTC -5 = CDT
UCT -6 = CST, MDT
UCT -7 = PDT
Coordinated Universal Time (UTC)
The worldwide scientific standard of timekeeping. It is based upon carefully maintained atomic clocks and is highly stable. The addition or subtraction of leap seconds, as necessary, at two opportunities every year adjusts UTC for irregularities in Earth’s rotation.
Spacecraft Event Time (SCET) or Orbiter UTC
The time something happens at the spacecraft, such as a science observation or engine burn.
One-Way Light Time (OWLT)
The time it takes for a signal – which moves at the speed of light through space – to travel from the spacecraft to Earth. From Saturn, one-way light time can range from about one hour and 14 minutes to one hour and 24 minutes.
Earth Received Time (ERT) or Ground UTC
The time the spacecraft signal is received at mission control on Earth (the Spacecraft Event Time plus One-Way Light Time).
Mission Elapsed Time (MET)
Used by NASA during their space missions. Because so much of the mission depends on the time of launch, all events after launch are scheduled on the Mission Elapsed Time. This avoids constant rescheduling of events in case the launchtime slips. The MET-clock is set to zero at the moment of liftoff and counts forward in normal days, hours, minutes, and seconds. For example, 2:03:45:18 MET means it has been 2 days, 3 hours, 45 minutes, and 18 seconds since liftoff.
Official U.S. Time
National Institute of Standards and Technology (NIST, U.S. Department of Commerce) and United States Naval Observatory (U.S. Department of Defense). United States Naval Observatory.
Conversion miles and feet to kilometers
- Miles x 1,60 = kilometer
- 250,000 miles = 400.000 kilometer (Distance to the Moon)
- 200,000 miles = 320.000 kilometer
- 50,000 miles = 80.000 kilometer
- 30,000 miles = 48.000 kilometer
- 25,000 miles = 40.000 kilometer
- 24,000 miles = 38.400 kilometer (Artemis I Entry Interface speed, Mach 32)
- 20,000 miles = 32.000 kilometer
- 15,000 miles = 24.000 kilometer
- 10,000 miles = 11,600 kilometer
- 5,000 miles = 8,000 kilometer
- 2,500 miles = 4,000 kilometer
- 1,000 miles = 1,600 kilometer
- 500 miles = 800 kilometer
- 100 miles = 160 kilometer
- 10 miles = 16 kilometer
- Feet x 0,30 = kilometer
- 400,000 feet = 120 kilometer (Artemis I Entry Interface altitude)
- 350,000 feet = 105 kilometer
- 300,000 feet = 90 kilometer (Artemis I Skip apogee)
- 250,000 feet = 75 kilometer
- 200,000 feet = 60 kilometer
- 150,000 feet = 45 kilometer
- 100,000 feet = 30 kilometer
- 50,000 feet = 15 kilometer
- 30,000 feet = 9,0 kilometer
- 28,000 feet = 8,4 kilometer
- 22,000 feet = 6,6 kilometer (Artemis I FBC jettison, Drogue parachutes)
- 6,800 feet = 2,0 kilometer (Artemis I Pilot parachutes)
- 5,000 feet = 1,5 kilometer (Artemis I Main parachutes)
An atomic clock measures by monitoring the resonant frequency of atoms. It is based on atoms having different energy levels. Electron states in an atom are associated with different energy levels, and in transitions between such states they interact with a very specific frequency of electromagnetic radiation. This phenomenon serves as the basis for the International System of Units’ (SI) definition of a second.
The accurate timekeeping capabilities are also used for navigation by satellite networks such as the European Union’s Galileo Program and the United States’ GPS. The timekeeping accuracy of the involved atomic clocks is important because the smaller the error in time measurement, the smaller the error in distance obtained by multiplying the time by the speed of light is (a timing error of a nanosecond or 1 billionth of a second (10−9 or 1⁄1,000,000,000 second) translates into an almost 30-centimetre (11.8 in) distance and hence positional error).