Pluto

SaturnJupiter

Neptune

EarthUranus

Voyager 1 18 billion kmfrom the sun

Voyager 2 15 billion kmfrom the sun

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The original mission of Voyager 1, a 722- kilogram spacecraft launched by NASA in 1977, was to study Jupiter and Saturn. After completing that, it was sent on another trajec-tory to take it out of the solar system. In February 1998, it overtook the space probe Pioneer (launched in 1972) to become the most distant man-made object in space. On Dec. 16, 2004 it crossed the termination shock zone and entered the outer reaches of our system. Voyager is still able to transmit data back to the Deep Space Network, and this week NASA reported that the craft had entered a “new region” suggesting it was now on the very edge of the solar system. Almost 35 years after being launched, and having travelled 18 billion kilometres, Voyager 1 is close to entering interstellar space.

❚ Plasma Wave Subsystem: The PWS measures electric field components oflocal plasma waves, useful in studying magnetospheres.

❚ High Gain Antenna: The radio communication system of Voyager 1 was designed to be used up to and beyond the limits of the solar system. The 3.7-metre diameter parabolic dish antenna is the most prominent aspect of Voyager and sends and receives radio waves via three Deep Space Network stations on Earth.As of Feb. 8, 2012, it took just over 16 hours for a signal sent from Voyager to be received on Earth.

❚ The Golden Record: Both Voyagers carry gold-plated, 12-inch copper phonograph records with sounds and images of Earth. Included are natural sounds of wind, waves and animals, 90 minutes of music from around the world, greetings in 55 languages including the 6,000-year-old Akkadian tongue, printed messages from former U.S. former president Jimmy Carter and the United Nations secretary-general. Instructions for playing the record are given as well as information about the origins of the spacecraft. The music includes Bach's Brandenberg Concerto No.2 in F First Movement, Johnny B. Goode by Chuck Berry and Melancholy Blues by Louis Armstrong.

❚ Low-Field Magnetometer

❚ Magnetometer: Measures magnetic fields. It can determine whether the outer planets have magnetic fields as well as measuring changes in the sun's magnetic fields. Also detects the effects of solar wind on planets and moons. The system is divided into low-field and high-field magnetometers to provide greater reliability.

❚ Infrared Spectrometer and Radiometer: Actually three separate instruments: 1. A sophisticated thermometer 2. A detector of elements or compounds present in atmospheres or surfaces 3. A radiometer that measures reflected sunlight at UV, visible and infrared frequencies.

❚ Photopolarimeter: The PPS instrument was designed to determine the physical properties of the atmospheres of Jupiter, Saturn, and the rings of Saturn.

VOYAGER 1 passed Jupiter

on March 5, 1979

VOYAGER 1 passed Saturn

on Nov. 13, 1980

❚ Imaging Science System: Uses a two-camera system (narrow-angle/wide-angle) to provide imagery of Jupiter, Saturn and other objects along the trajectory.

❚ Ultraviolet Spectrometer: Measures atmospheric properties and UV radiation.

❚ Low-Energy Charged Particle Detector (LECP): Looks for high-energy particles. According to the NASA Voyager 1 Website, “The LECP can be imagined as a piece of wood, with the particles of interest playing the role of bullets. The faster a bullet moves, the deeper it will penetrate the wood. Thus, the depth ofpenetration measures the speed of the particles. The number of ‘bullet holes’ over time indicates how many particles there are in various places in the solar wind, and at the various outer planets. The orientation of the wood indicates the direction from which the particles came.”

EXITING THESOLAR SYSTEM

HELIOSPHERENASA describes the heliosphere as an immense magnetic bubble

containing our solar system, solar wind and the entire solar magnetic field. Virtually all of the material in the heliosphere

emanates from the sun itself.

TERMINATION SHOCKBlowing outward billions of kilometres from the sun is the solar wind, a thin

stream of electrically charged gas. This wind travels at an average speed ranging from 300 to 700 kilometres per second until it reaches the

termination shock. At this point, the speed of the solar wind drops abruptly as it begins to feel the effects of interstellar wind.

The HELIOSHEATH isthe outer region of the

heliosphere and is estimated by NASA to be

about 3.7 billion to 4.7 billion km wide. Voyager entered the heliosheath

about 14 billion kilometres from the sun. This is about 94 times the distance from

the sun to Earth.The HELIOPAUSE is the

boundary beyond which the solar wind no longer blows.

Once Voyager passes the heliopause, it will be in

interstellar space.

WHERE THE VOYAGERS ARE NOW

VOYAGER ONE

Earth

Moon

Venus

Jupiter

Saturn

Mercury

Mars

Sun

❚ Cosmic Ray detector: The most sensitive of the particle detectors. The CRS looks for energy particles in plasma. The CRS measured the particle charge composition in the magnetosphere of Jupiter, Saturn, Uranus and Neptune. It also provides data on the energy content, origin, acceleration process, life history and dynamics of cosmic rays in the galaxy.

❚ Optical Calibration Target Plate: A flat rectangle of known colour and brightness that cameras and infrared instruments can point to for calibration.

OUR SOLAR SYSTEM

❚ Radioisotope Thermoelectric Generator (RTG): Three RTG units are the central power source for the mission module. They are fuelled by radioisotopic plutonium-238.

❚ Planetary Radio Astronomy (PRA) & Plasma Wave Subsystem (PWS): The PRA is a sophisticated radio receiver that listens for radio signals produced by the sun, planets and their magnetospheres and lightnings. It's an instrument designed to try to learn more about planetary radio emissions and planetary atmospheres.

❚ Plasma Spectrometer: “The PLS looks for the lowest-energy particles in plasma. It also has the ability to look for particles moving at particular speeds and, to a limited extent, to determine the direction from which they come.” Its main objectives are to measure plasma, solar wind and interstellar ions.

Voyager 1 was launched on Sept. 5, 1977 on a mission to study the planets of Jupiter and Saturn.

ANDREW BARR, JOSHUA LEARN & RICHARD JOHNSON / NATIONAL POSTSOURCE: NATIONAL AERONAUTICS AND SPACE ADMINISTRATION

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