PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION 
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011

                     Voyager Mission Status
                        November 1, 1995

     Voyager 1 is currently 9.15 billion kilometers (5.69 billion 
miles) from Earth, having traveled 10.87 billion kilometers (6.75 
billion miles) since its launch in September 1977. The Voyager 1 
spacecraft is departing the solar system at a speed of 17.46 
kilometers per second (39,055 miles per hour).

     Voyager 2 is currently 7 billion kilometers (4.35 billion 
miles) from Earth, having traveled 10.28 billion kilometers (6.38 
billion miles) since its launch in August 1977. The Voyager 2 
spacecraft is departing the solar system at a speed of 16.08 
kilometers per second (35,970 miles per hour).

     Both Voyager spacecraft are healthy and continue their 
departure from the solar system.  As they travel farther and 
farther from the Sun, the two spacecraft are returning data to 
characterize the outer solar system environment and search for 
the heliopause boundary, the outer limit of the Sun's magnetic 
field and outward flow of the solar wind.  

     Six science instruments on each Voyager spacecraft are 
collecting data on the strength and orientation of the Sun's 
magnetic field; the composition, direction and energy specta of 
the solar wind particles and interstellar cosmic rays; the 
strength of radio emissions that are thought to be originating at 
the heliopause, beyond which is interstellar space; and the 
distribution of hydrogen within the outer heliopause.  These data 
are transmitted to Earth in real time, at 160 bits per second, 
and captured by 34-meter-diameter antennas of the Deep Space 
Network.  Data are transmitted to JPL and made available in 
electronic files to the science teams located around the country 
for processing and analysis.

     Flight controllers believe both spacecraft will continue 
to operate and send back valuable data until at least the year 
2015.  It is the loss of  electrical power from their 
radioisotope thermoelectric generators (RTGs) that will 
eventually cause them to stop functioning.  At launch, the three 
RTGs on each spacecraft had a power output of 475 watts.  Today, 
that output is 341 watts for Voyager 1 and 345 watts for Voyager 
2.   Approximately 215 watts are necessary to operate the 
spacecraft and limited cience instruments.

     The other vital consumable onboard the spacecraft is the 
amount of hydrazine propellant which keeps the Voyagers stable 
and pointed toward Earth.  Each spacecraft started out with 104 
kilograms of propellant.  Today,  after 18 years of flight, 
including multiple planetary encounters and trajectory correction 
maneuvers, Voyager 1 has 34 kilograms of hydrazine remaining and 
Voyager 2 has 36 kilograms remaining.  However, during the 
current, quiet phase of the mission, each spacecraft uses only 
about six grams of fuel a week. Flight controllers stress the 
Voyagers will run out of electrical power long before they start 
spinning out of control due to loss of their attitude-adjusting 
propellant.

     It is estimated that Voyager 1 will pass the Pioneer 10 
spacecraft in January 1998 to become the most distant human-made 
object in space.

       
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