NASA's
Deep Space Network (DSN) has been in partnership with
Voyager 1 and Voyager 2 for thirty years, providing
daily communications support to the two very distant
spacecraft. The excellent partnership continues as the
Voyager twin spacecraft explore the regions of our universe
near the area where the solar wind meets the interstellar
winds – areas never before explored by human-made
objects.
Voyager 1 reached a historic milestone in December 2004 when it crossed the termination shock where the solar wind slows abruptly from a speed that ranges from 700,000 to 1.5 million mph. Another important milestone was reached on August 15, 2006 when Voyager 1 became 100 AU (Astronomical Unit) from the Sun! One AU is the average distance from Earth to the Sun, 150 million km, or 93 million miles.
As
of July 2, 2007, at the speed of light, it takes 14 hours
and 12 minutes for a signal from Voyager 1 to travel
over 103 AU to reach one of
the
giant
antennas of the DSN, and 11 hours and 24 minutes for
Voyager 2, which is over 83 AU away.
The above diagram shows the current positions of Voyager 1 and Voyager 2 and depicts the termination shock, heliosphere, heliosheath, heliopause and bow shock, The source of the diagram as well as the information below is the Voyager Project. The solar wind is a stream of electrically charged ions ejected from the Sun's atmosphere, which sweeps past all the planets at supersonic speeds. It creates a bubble around the Sun, called the heliosphere, which extends far beyond the orbits of the planets. Inside the heliosphere is a boundary called the termination shock where the speed of the supersonic solar wind is suddenly reduced. The outer boundary of the heliosphere, where the expanding solar wind is balanced by the inward pressure of interstellar matter is called the heliopause. The heliosheath is the region between the termination shock and the heliopause. A bow shock forms as the Sun progresses through the ionized interstellar gas.
Because of the enormous distances and the resultant weak signals from the spacecraft, the large antennas and the very sensitive receivers of the DSN are required to provide the necessary communications capabilities. The DSN is the world's largest and most sensitive spacecraft communications network. It consists of three deep space communications complexes located approximately 120 degrees of longitude apart around the world: at Goldstone, California; near Madrid, Spain; and near Canberra, Australia. This placement permits continuous communication with a spacecraft.
Each deep space communications complex provides capabilities required to perform telemetry data processing, including signal reception and amplification, signal demodulation and decoding, and data extraction. It also provides a capability to send commands generated by the project to the Voyager spacecraft. All DSN complexes are linked to JPL via a world-wide communications network.
The
Deep Space Network, the premier network for deep space
communications, allows the Voyager spacecraft to continue
to send new and unique data from the far reaches of space.
Voyager 1 is the farthest spacecraft from the Sun, even
beyond the recently discovered Sedna, and Voyager 2 is
the second farthest operating spacecraft. As these distances
continue to increase, the DSN is implementing new techniques,
such as arraying of antenna and combining of weak signals,
that will allow continuing excellent support of the Voyager
spacecraft.
The
thrilling discoveries during Voyager's 30 years of operation,
including the grand tour of the outer planets, would
not have been possible without the sustained exemplary
support of the Deep Space Network. The excellent Voyager-DSN
partnership continues during the Voyager Interstellar
Mission as Voyager 1 and 2 enter the transition region
between the heliosphere and interstellar space and become
humanity's first interstellar probes.
