[sci.astro] Magellan Update - 01/17/90

baalke@mars.jpl.nasa.gov (Ron Baalke) (01/19/90)

 
                     MAGELLAN STATUS REPORT
                          Jan. 17, 1990
 
     Today, the Magellan spacecraft is 113,471,037 miles from
Earth, traveling at a speed of 63,409 miles per hour relative to
the sun. One way light time is 10 minutes and 12 seconds.
 
     The spacecraft has been successfully switched back to its
primary command data system computer, and to the high-gain
antenna. The data rate is again at 1,200 bits per second. Earlier
this month the spacecraft detected an error in its memory and
went into a safing mode. It switched to its backup CDS computer
and the telemetry link was switched from the high gain to the
medium gain antenna and the rate was reduced from 1,200 bits per
second to 40 bps.
 
     Also, the command link was switched from the high gain to
the low gain and the rate was reduced from 62.5 bps to 7.8 bps.
 
     On January 12, the spacecraft went into fault protection mode
due to a wrong command to the spacecraft from the spacecraft team.
After performing a sweep at 300Hz with a tuning rate of 5Hz/sec,
two way communications was once again established.
 
     A momentum wheel desaturation was done once daily via non-
standard commands to the spacecraft.
 
     Magellan operations team members said Magellan is back on
schedule for the start of Cruise-17 command sequence
 

 Ron Baalke                       |    baalke@mars.jpl.nasa.gov 
 Jet Propulsion Lab  M/S 301-355  |    baalke@jems.jpl.nasa.gov 
 4800 Oak Grove Dr.               |
 Pasadena, CA 91109               |

roy@phri.nyu.edu (Roy Smith) (01/19/90)

In <2595@jato.Jpl.Nasa.Gov> baalke@mars.jpl.nasa.gov (Ron Baalke) writes:
> Today, the Magellan spacecraft is 113,471,037 miles from Earth

	Arghh!  Why do they give the distances to 9 significant figures?
Considering that the thing is moving at about 1.5 million miles per day, to
quote today's distance to a precision of units of miles is absurd.  Do they
do this just because it sounds better to the lay public?
--
Roy Smith, Public Health Research Institute
455 First Avenue, New York, NY 10016
roy@alanine.phri.nyu.edu -OR- {att,philabs,cmcl2,rutgers,hombre}!phri!roy
"My karma ran over my dogma"