Category : Science and Education
Archive   : JPL9209.ZIP
Filename : JPLCLOCK.MSG

Welcome to JPLCLOCK!
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Written by
David H. Ransom, Jr.
Rancho Palos Verdes, CA


JPLCLOCK is a real time clock and mission/event timer program written
especially for the NASA Jet Propulsion Laboratory in Pasadena, California for
use in the Multimission Computer Control Center (MCCC) and elsewhere in the
Laboratory. The MCCC is the "nerve center" where all the NASA planetary
missions such as Magellan, Ulysses, and Galileo are controlled. Other NASA and
European Space Agency missions are also supported by the JPL MCCC either
directly or through NASA's Deep Space Network, three large antenna systems
located in Goldstone, California, near Madrid, Spain and near Canberra,
Australia. The MCCC is in turn supported by the scientists and engineers at JPL
and at the California Institute of Technology, which operates JPL for NASA.


TIME REFERENCE

JPLCLOCK is projected on a large screen and functions as the secondary
time reference for the Multimission Computer Control Center:

É[ NASA Jet Propulsion Laboratory ]ÍÍÍÍÍÍÍÍÍÍÍÍÍÍ»
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DEEP SPACE NETWORK AND LOCATION CLOCKS

When JPLCLOCK is used in the Mission Control Center, the local time at
each of the three Deep Space Network (DSN) stations is displayed in the clock
windows located below the Main Window. In this example, the local time at the
Johnson Space Center (JSC) in Houston, Texas has also been included. The time
is shown as Day-of-the-Year, Local Time, and Time Zone Abbreviation.


Ú[ GDS Goldstone ]ÄÄÄÄ¿ Ú[ CAN Canberra ]ÄÄÄÄÄ¿
³ 165 20:18:25 PDT ³ ³ 166 14:18:25 ³
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Ú[ JSC Houston ]ÄÄÄÄÄÄ¿ Ú[ MAS Madrid ]ÄÄÄÄÄÄÄ¿
³ 165 22:18:25 CDT ³ ³ 166 04:18:25 CES ³
ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ




MISSION/EVEMT TIMERS Ú[ Magellan ]ÄÄÄÄÄÄÄÄÄÄÄÄÄ¿
Another key function of JPLCLOCK is to ³ 604 12:18:25 ³
display Mission and Event Timers. A total of 60 ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ
timers is available, six of which are displayed at
any given time on the right side of the display Ú[ Ulysses ]ÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿
screen. Each timer can display the time until an ³ 251 15:31:10 ³
event occurs (up to -27 years) or the time since ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ
an event occured (up to +274 years!).
Events which have not yet occured operate as Ú[ Galileo ]ÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿
a "count down" clock and are shown with a RED ³ 616 14:18:25 ³
background. When an event is within 24 hours of ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ
its Time Zero, flashing asterisks appear.
Events which have already occured operate as Ú[Hubble Space Telescope]Ä¿
a "count up" clock and are shown with a GREEN ³ 403 14:44:33 ³
background. The time is shown as Days followed by ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ
the time in Hours:Minutes:Seconds. The MCCC
continues to support long duration missions such Ú[ Gamma Ray Observatory]Ä¿
as the twin Voyager spacecraft, already more then ³ 70 11:55:40 ³
14 years into their missions. ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ

AUTOMATIC MISSION TIMER AND TEXT PRESENTATION

JPLCLOCK may also be used as a public information system, displaying
current mission events and supplementary text information. This is the program
mode now being used.
When used in this mode, JPLCLOCK cycles through all active Mission/Event
Timers and text pages at a predetermined rate as it is doing now. Whenever a
Mission/Event Timer is within plus or minus one hour of Time Zero, the page
including that timer is held on the screen. When the critical "freeze" time is
passed, the program resumes cycling through the timer and text pages.

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JPLCLOCK will resume real time display after this screen.