Spacecraft Clock (SCLK)

Connections

How Spacecraft Clock (SCLK) connects across Asteria Star — scientific, cultural, and astrological links are kept separate.

Related entities

• Tracking network

  Deep Space Network (DSN)

  NASA's international array of giant radio antennas — at Goldstone (California), Madrid, and Canberra — that communicates with interplanetary spacecraft and distant satellites, spaced around the globe for continuous coverage.

• Time standard

  Apparent Solar Time

  Time kept by the real Sun, as a sundial shows it — noon is the moment the Sun crosses the meridian. Because the Earth's orbit is elliptical and tilted, the Sun runs fast or slow through the year, so clocks keep mean solar time instead, differing by up to about a quarter of an hour.

• Time standard

  Barycentric Dynamical Time

  The time coordinate of the Solar System barycentre, used as the independent variable of the planetary ephemerides. It differs from Terrestrial Time only by small periodic terms arising from the Earth's motion around the Sun, never drifting by more than a couple of milliseconds.

• Time standard

  Coordinated Universal Time (UTC)

  The civil time standard, derived from International Atomic Time but kept within a second of the Earth's rotation by occasional leap seconds. Deep-space tracking tags its measurements in UTC.

• Time standard

  GPS Time

  The continuous timescale of the Global Positioning System, offset from TAI by a fixed number of seconds and widely used to synchronise ground equipment.

• Time standard

  International Atomic Time (TAI)

  A continuous atomic timescale kept by hundreds of atomic clocks worldwide — the stable foundation from which civil time is derived. TAI never inserts leap seconds, making it ideal for measuring precise intervals.

• Time standard

  Julian Date

  A continuous count of days (and fractions) since noon Universal Time on 1 January 4713 BC in the proleptic Julian calendar, used throughout astronomy to timestamp observations without the awkwardness of calendar months and leap years. The Modified Julian Date (MJD = JD − 2400000.5) shifts the origin to a recent midnight for convenience.

You might also explore

• Time standardCoordinated Universal Time (UTC)Linked through Deep Space Network (DSN)
• Tracking stationCanberra Deep Space Communication ComplexLinked through Deep Space Network (DSN)
• Space missionCassini–HuygensLinked through Deep Space Network (DSN)
• Tracking networkCommercial Deep-Space ServicesLinked through Deep Space Network (DSN)
• Space missionDARTLinked through Deep Space Network (DSN)
• Navigation systemDelta-DORLinked through Deep Space Network (DSN)

Sources & references

Facts on this topic will be cited from these primary and reference sources.

• NASANational Aeronautics and Space Administration

  Mission data, planetary science, space telescopes, and public-domain imagery.

  Most NASA-produced imagery is in the public domain; individual items are checked for usage terms before publication.

• NASA JPLJet Propulsion Laboratory / Solar System Dynamics

  Orbital data, ephemerides, and small-body parameters for planets, asteroids, and comets.