Pioneer 10

Pioneer 10

Artist's conception of Pioneer 10 on its way to interstellar space
Mission type	Planetary / Heliosphere exploration
Operator	NASA / Ames
COSPAR ID	1972-012A
SATCAT no.	5860
Website	science.nasa.gov
Mission duration	30 years, 10 months and 21 days
Spacecraft properties
Spacecraft	Pioneer F
Manufacturer	TRW
Launch mass	258 kg
Power	155 watts (at launch)
Start of mission
Launch date	March 3, 1972 (1972-03-03), 01:49:04 UTC
Rocket	Atlas SLV-3C Centaur-D Star-37E
Launch site	Cape Canaveral LC-36A
End of mission
Disposal	Decommissioned
Declared	31 March 1997
Last contact	27 April 2002 Last telemetry 23 January 2003 Last signal received
Flyby of Jupiter
Closest approach	December 3, 1973 (1973-12-03)
Distance	132,252 km (82,178 mi)
Instruments HMV Helium Vector Magnetometer - Quadrispherical Plasma Analyzer CPI Charged Particle Instrument CRT Cosmic Ray Telescope GTT Geiger Tube Telescope TRD Trapped Radiation Detector - Meteoroid Detectors AMD Asteroid/Meteoroid Detector - Ultraviolet Photometer IPP Imaging Photopolarimeter - Infrared Radiometer
Pioneer program

Pioneer 10 (originally designated Pioneer F) is a NASA space probe launched in 1972 that completed the first mission to the planet Jupiter. Pioneer 10 became the first of five artificial objects to achieve the escape velocity needed to leave the Solar System. This space exploration project was conducted by the NASA Ames Research Center in California. The space probe was manufactured by TRW Inc.

Pioneer 10 was assembled around a hexagonal bus with a 2.74-meter (9 ft 0 in) diameter parabolic dish high-gain antenna, and the spacecraft was spin stabilized around the axis of the antenna. Its electric power was supplied by four radioisotope thermoelectric generators that provided a combined 155 watts at launch.

It was launched on March 3, 1972, at 01:49:00 UTC (March 2 local time), by an Atlas-Centaur rocket from Cape Canaveral, Florida. Between July 15, 1972, and February 15, 1973, it became the first spacecraft to traverse the asteroid belt. Photography of Jupiter began on November 6, 1973, at a range of 25 million kilometers (16 million miles), and about 500 images were transmitted. The closest approach to the planet was on December 3, 1973, at a range of 132,252 kilometers (82,178 mi). During the mission, the on-board instruments were used to study the asteroid belt, the environment around Jupiter, the solar wind, cosmic rays, and eventually the far reaches of the Solar System and heliosphere.

Radio communications were lost with Pioneer 10 on January 23, 2003, because of the loss of electric power for its radio transmitter. At the time, the probe was 12 billion km (80 AU; 7.5 billion mi) from Earth.

Mission background

History

In the 1960s, American aerospace engineer Gary Flandro of the NASA Jet Propulsion Laboratory conceived a mission known as the Planetary Grand Tour that would exploit a rare alignment of the outer planets of the Solar System. This mission would ultimately be accomplished in the late 1970s by the two Voyager probes, but to prepare for it, NASA decided in 1964 to test the concept by launching a pair of probes to the outer Solar System. An advocacy group, the Outer Space Panel, chaired by American space scientist James A. Van Allen, worked out the scientific rationale for exploring the outer planets. NASA Goddard Spaceflight Center put together a proposal for a pair of "Galactic Jupiter Probes" that would pass through the asteroid belt and visit Jupiter. The probes were to be launched in 1972 and 1973 during favorable launch windows that occurred for only a few weeks every 13 months. Launch during other time intervals would have been more costly in terms of propellant requirements.

Approved by NASA in February 1969, the twin spacecraft were designated Pioneer F and Pioneer G before launch; later, they were named Pioneer 10 and Pioneer 11, respectively. They formed part of the Pioneer program, a series of United States uncrewed space missions launched between 1958 and 1978. These spacecraft were the first in the series designed to explore the outer Solar System. Based on proposals issued throughout the 1960s, the early mission objectives were to explore the interplanetary medium beyond Mars's orbit, study the asteroid belt, assess the possible hazards to spacecraft traveling through it, and explore Jupiter and its environment. Later development-stage objectives included a close approach to Jupiter to measure the effects of the planet's radiation environment on the spacecraft's instruments.

More than 150 scientific experiments were proposed for the missions. The experiments to be carried on board were selected in a series of planning sessions during the 1960s and finalized by early 1970. These would be to perform imaging and polarimetry of Jupiter and several of its satellites, make infrared and ultraviolet observations of Jupiter, detect asteroids and meteoroids, determine the composition of charged particles, and to measure magnetic fields, plasma, cosmic rays and the zodiacal light. Observations of the spacecraft's radio transmissions as it passed behind Jupiter would allow measurements of the planet's atmosphere, while tracking data would improve estimates of the mass of Jupiter and its moons.

NASA Ames Research Center, rather than Goddard, was selected to manage the project as part of the Pioneer program. The Ames Research Center, under the direction of Charles F. Hall, was chosen because of its previous experience with spin-stabilized spacecraft. The requirements called for a small, lightweight spacecraft that was magnetically clean and could perform an interplanetary mission. The design incorporated modules that had already been proven in the Pioneer 6 through 9 missions. Ames also commissioned a documentary film by George Van Valkenburg titled Jupiter Odyssey. It received numerous international awards and is visible on Van Valkenburg's YouTube channel.

In February 1970, Ames awarded a combined US$380 million contract to TRW Inc. for building both of the Pioneer 10 and 11 vehicles, bypassing the usual bidding process to save time. B. J. O'Brien and Herb Lassen led the TRW team responsible for assembling the spacecraft. Design and construction required an estimated 25 million man-hours. An engineer from TRW quipped, "This spacecraft is guaranteed for two years of interplanetary flight. If any component fails within that warranty period, just return the spacecraft to our shop and we will repair it free of charge."

To meet the schedule, the first launch would need to take place between February 29 and March 17 to arrive at Jupiter in November 1974. The schedule was later revised to target an arrival in December 1973, avoiding conflicts with other missions using the Deep Space Network and the period when Earth and Jupiter would be on opposite sides of the Sun. The encounter trajectory for Pioneer 10 was selected to maximize the information returned about the radiation environment around Jupiter, even if this caused damage to some systems. The planned trajectory brought the spacecraft within about three times the radius of the planet, which was considered the closest safe approach that would still allow the spacecraft to survive the radiation environment. The selected trajectory also provided the spacecraft with a good view of the sunlit side.

• 
  Pioneer 10 and Pioneer 11 spacecraft diagram
• 
  Pioneer 10 in the final stages of construction (December 1971)
• 
  Pioneer 10 tested in a space simulation chamber (January 1972)
• 
  Pioneer 10 on a Star-37E kick motor just prior to being encapsulated for launch (February 1972)
• 
  Pioneer 10 during encapsulation into payload fairing

Spacecraft design

The Pioneer 10 spacecraft bus formed a hexagonal structure measuring 36 centimeters (14 in) deep, with six 76-centimeter (30 in) long panels. The bus contained the propellant system used to control the spacecraft's orientation and housed eight of its eleven scientific instruments. The equipment compartment was enclosed within an aluminum honeycomb structure that protected it from meteoroid impacts. A layer of insulation consisting of aluminized mylar and kapton blankets provided passive thermal control. Heat generated by the electrical components inside the compartment was dissipated at a rate of 70 to 120 watts (W). Louvers located below the mounting platform regulated the temperature within the operating limits of the equipment. The spacecraft had a launch mass of about 260 kilograms (570 lb).

At launch, the spacecraft carried 36 kilograms (79 lb) of liquid hydrazine monopropellant stored in a 42-centimeter (17 in) diameter spherical tank. The spacecraft's orientation was controlled by six 4.5 N hydrazine thrusters arranged in three pairs. One pair maintained the spacecraft's constant spin rate of 4.8 rpm, another controlled forward thrust, and the third controlled attitude adjustments. The attitude thrusters were used for conical scanning maneuvers, which allowed the spacecraft to maintain communication with Earth as it traveled through space. Additional orientation information was provided by a star sensor that used Canopus as a reference point and by two Sun sensors.

Power and communications

SNAP-19 RTGs mounted on an extension boom of Pioneer 10 replica

Pioneer 10 was powered by four SNAP-19 radioisotope thermoelectric generators (RTGs). The RTGs were mounted on two three-rod trusses, each 3 meters (9.8 ft) long and separated by 120 degrees. This placement minimized interference with the spacecraft's sensitive scientific instruments. Together, the RTGs produced 155 W at launch, declining to 140 W during the journey to Jupiter. The spacecraft required 100 W to power all systems. The generators were fueled by plutonium-238 contained in multilayer capsules protected by graphite heat shields.

The pre-launch requirement for the SNAP-19 was to provide power for two years in space; this was greatly exceeded during the mission. Plutonium-238 has a half-life of 87.74 years, so radioactive decay alone reduced the RTGs' output only gradually. However, deterioration of the thermocouple junctions caused electrical power generation to decline more rapidly, and by 2001, the total power output was 65 W. As a result, only selected instruments could be operated simultaneously during the later stages of the mission.

The spacecraft included a redundant communications system with two transceivers, one connected to the narrow-beam high-gain antenna and the other to the omnidirectional and medium-gain antennas. The parabolic dish for the high-gain antenna was 2.74 meters (9.0 ft) in diameter and was made from an aluminum honeycomb sandwich material. The spacecraft was spun about an axis parallel to that of the antenna so that it remained oriented toward Earth. Each transceiver had a power output of 8 W and transmitted data in the S-band using 2110 MHz for the uplink from Earth and 2292 MHz for the downlink. The Deep Space Network tracked the signal. Data were passed through a convolutional encoder so that most communication errors could be corrected by the receiving equipment on Earth. The data transmission rate at launch was 256 bit/s, with the rate degrading by about 1.27 millibit/s for each day during the mission.

Much of the mission's computation was performed on Earth and transmitted to the spacecraft. It could store up to five commands at a time from a library of 222 command sequences prepared by ground controllers. The onboard computer consisted of two command decoders and a command distribution unit that provided limited onboard processing capability and directed spacecraft operations. This system required mission operators to prepare command sequences well in advance of transmission. A data storage unit recorded up to 6,144 bytes of information gathered by the instruments. The digital telemetry unit prepared the collected data in one of thirteen transmission formats before sending it to Earth.

Scientific instruments

Helium Vector Magnetometer (HVM)
	This instrument measured the fine structure of the interplanetary magnetic field, mapped the Jovian magnetic field, and provided magnetic field measurements to evaluate solar wind interaction with Jupiter. The magnetometer consisted of a helium-filled cell mounted on a 6.6 m boom to partly isolate the instrument from the spacecraft's magnetic field. Principal investigator: Edward Smith / JPL Data: PDS/PPI data catalog, NSSDC data archive
Quadrispherical Plasma Analyzer
	The plasma analyzer peered through a hole in the large dish-shaped antenna to detect particles of the solar wind originating from the Sun. Principal investigator: Aaron Barnes / NASA Ames Research Center Data: PDS/PPI data catalog, NSSDC data archive
Charged Particle Instrument (CPI)
	This instrument detected cosmic rays in the Solar System. Principal investigator: John Simpson / University of Chicago Data: NSSDC data archive
Cosmic Ray Telescope (CRT)
	This instrument collected data on the composition of the cosmic ray particles and their energy ranges. Principal investigator: Frank B. McDonald / NASA Goddard Space Flight Center Data: PDS/PPI data catalog, NSSDC data archive
Geiger Tube Telescope (GTT)
	The Geiger tube telescope surveyed the intensities, energy spectra, and angular distributions of electrons and protons along the spacecraft's path through the radiation belts of Jupiter. Principal investigator: James A. Van Allen / University of Iowa Data: PDS/PPI data catalog, NSSDC data archive
Trapped Radiation Detector (TRD)
	This instrument included an unfocused Cerenkov counter that detected the light emitted in a particular direction as particles passed through it recording electrons of energy, 0.5 to 12 MeV, an electron scatter detector for electrons of energy, 100 to 400 keV, and a minimum ionizing detector consisting of a solid-state diode that measured minimum ionizing particles (<3 MeV) and protons in the range of 50 to 350 MeV. Principal investigator: R. Fillius / University of California San Diego Data: NSSDC data archive
Meteoroid Detectors
	The meteoroid detectors consisted of twelve panels of pressurized cell detectors mounted on the back of the main dish antenna that recorded penetrating impacts of small meteoroids. Principal investigator: William Kinard / NASA Langley Research Center Data: NSSDC data archive list
Asteroid/Meteoroid Detector (AMD)
	The meteoroid-asteroid detector looked into space with four non-imaging telescopes to track particles ranging from close by bits of dust to distant large asteroids. Principal investigator: Robert Soberman / General Electric Company Data: NSSDC data archive
Ultraviolet Photometer
	Ultraviolet light (200 to 800 Å) was sensed by the UV photometer to determine the quantities of hydrogen and helium in space and on Jupiter. Principal investigator: Darrell Judge / University of Southern California Data: PDS/PPI data catalog, NSSDC data archive
Imaging Photopolarimeter (IPP)
	The imaging experiment relied upon the spin of the spacecraft to sweep a small telescope across the planet in narrow strips only 0.03 degrees wide, looking at the planet in red (5800 to 7000 Å) and blue (3900 to 4900 Å) light. These strips were then processed to build up a visual image of the planet. Principal investigator: Tom Gehrels / University of Arizona Data: NSSDC data archive list
Infrared Radiometer
	This instrument provided information on cloud temperature and the output of heat from Jupiter. Principal investigator: Andrew Ingersoll / California Institute of Technology

Mission profile

Launch and trajectory

The launch of Pioneer 10

Pioneer 10 was launched on March 3, 1972, at 01:49:00 UTC (8:49 p.m. Eastern Standard Time on March 2) from Cape Canaveral Launch Complex 36A, aboard an Atlas-Centaur. The third stage of the expendable vehicle consisted of a solid-fuel Star-37E stage (TE-M-364-4) developed specifically for the Pioneer program. This stage provided about 67 kilonewtons (15,000 lbf) of thrust and spun the spacecraft up to its initial rotation rate. The spacecraft had an initial spin rate of 30 rpm. Twenty minutes after launch, the vehicle's three booms were extended, which slowed the rotation rate to 4.8 rpm. The spacecraft maintained this spin rate for the remainder of the mission. The launch vehicle accelerated the spacecraft for 17 minutes, reaching a velocity of 51,682 km/h (32,114 mph).

After contact was established with the spacecraft through the high-gain antenna, several instruments were activated for testing while the spacecraft was moving through the Earth's radiation belts. Ninety minutes after launch, the spacecraft reached interplanetary space. Pioneer 10 passed by the Moon in 11 hours, and became the fastest human-made object at that time. Two days after launch, the scientific payload was activated, beginning with the cosmic ray telescope. Within ten days, all instruments were operational.

During the first seven months of the journey, the spacecraft made three course corrections. The onboard instruments underwent checkouts, during which the photometers examined Jupiter and the zodiacal light, while other instruments measured cosmic rays, magnetic fields, and the solar wind. The only anomaly during this interval was the failure of the Canopus sensor, requiring the spacecraft to maintain its orientation using the two Sun sensors.

While passing through the interplanetary medium, Pioneer 10 became the first mission to detect interplanetary atoms of helium. It also observed high-energy ions of aluminum and sodium in the solar wind. In early August 1972, the spacecraft detected a solar shock wave at a distance of 2.2 AU (330 million km; 200 million mi), providing valuable heliophysics data. On July 15, 1972, Pioneer 10 was the first spacecraft to enter the asteroid belt, located between the orbits of Mars and Jupiter. Mission planners expected the spacecraft to pass safely through the belt, and the closest predicted approach to any known asteroid was 8.8 million kilometers (5.5 million miles). One of the nearest approaches was to the asteroid 307 Nike on December 2, 1972.

The onboard experiments demonstrated a deficiency of particles below a micrometer (μm) in the belt, as compared with near-Earth space. The density of dust particles between 10 and 100 μm remained nearly constant between Earth and the outer edge of the belt. Only particles between 100 μm and 1.0 mm in diameter increased in density by a factor of three within the belt. No fragments larger than a millimeter were observed in the belt, indicating that such fragments were much rarer than expected. Because the spacecraft encountered no large particles, it passed safely through the asteroid belt, emerging on the other side on about February 15, 1973.

• 
  NASA map showing trajectories of the Pioneer 10, Pioneer 11, Voyager 1, and Voyager 2 spacecraft.
• 
  Pioneer 10's trajectory through the Jovian system
• 
  Animation of Pioneer 10's trajectory from March 3, 1972, to December 31, 1975
     Pioneer 10  ·   Earth ·   Jupiter
• 
  Animation of Pioneer 10's trajectory around Jupiter
     Pioneer 10  ·   Jupiter ·   Io ·   Europa ·   Ganymede ·   Callisto

Encounter with Jupiter

On November 6, 1973, the Pioneer 10 spacecraft was at a distance of 25 million km (16 million mi) from Jupiter. Testing of the imaging system began, and the data were successfully received back at the Deep Space Network. A series of 16,000 commands were then uploaded to the spacecraft to control the flyby operations during the next sixty days. The orbit of the outer moon Sinope was crossed on November 8. The bow shock of Jupiter's magnetosphere was reached on November 16, as indicated by a drop in the velocity of the solar wind from 451 km/s (280 mi/s) to 225 km/s (140 mi/s). The magnetopause was passed through a day later. The spacecraft instruments confirmed that the magnetic field of Jupiter was inverted compared to that of Earth. By the 29th, the orbits of all of the outermost moons had been passed, and the spacecraft was operating flawlessly.

Red and blue pictures of Jupiter were being generated by the imaging photopolarimeter as the rotation of the spacecraft carried the instrument's field of view past the planet. These red and blue colors were combined to produce a synthetic green image, allowing a three-color combination to produce the rendered image. On November 26, a total of twelve such images were received back on Earth. By December 2, the image quality exceeded the best images made from Earth. These were being displayed in real-time back on Earth, and the Pioneer program would later receive an Emmy Award for this presentation to the media. The motion of the spacecraft produced geometric distortions that later had to be corrected by computer processing. During the encounter, a total of more than 500 images were transmitted.

The trajectory of the spacecraft took it along the magnetic equator of Jupiter, where the ion radiation was concentrated. Peak flux for this electron radiation is 10,000 times stronger than the maximum radiation around the Earth. Pioneer 10 passed through the inner radiation belts within 20 R_J, receiving an integrated dose of 200,000 rads from electrons and 56,000 rads from protons (in comparison, a whole-body dose of 500 rads is fatal to humans). The level of radiation at Jupiter was ten times more powerful than Pioneer's designers had predicted, leading to fears that the probe would not survive. Starting on December 3, the radiation around Jupiter caused false commands to be generated. Most of these were corrected by contingency commands, but an image of Io and a few close-ups of Jupiter were lost. Similar false commands would be generated on the way out from the planet. Nonetheless, Pioneer 10 did succeed in obtaining images of the moons Ganymede and Europa. The image of Ganymede showed low albedo features in the center and near the south pole, while the north pole appeared brighter. Europa was too far away to obtain a detailed image, although some albedo features were apparent.

The trajectory of Pioneer 10 was chosen to take it behind Io, allowing the refractive effect of the moon's atmosphere on the radio transmissions to be measured. This demonstrated that the ionosphere of the moon was about 700 kilometers (430 mi) above the surface of the day side, and the density ranged from 60,000 electrons per cubic centimeter on the dayside to 9,000 electrons per cubic centimeter on the night side. An unexpected discovery was that Io was orbiting within a cloud of hydrogen that extended for about 805,000 kilometers (500,000 mi), with a width and height of 402,000 kilometers (250,000 mi). A smaller, 110,000-kilometer (68,000 mi) cloud was believed to have been detected near Europa.

It was not until after Pioneer 10 had cleared the asteroid belt that NASA selected a trajectory towards Jupiter which included a slingshot effect to send the spacecraft out of the Solar System. Pioneer 10 was the first spacecraft to attempt such a maneuver, a model for future missions. Such an extended mission was not in the initial proposal, but was planned for before launch.

At the closest approach, the velocity of the spacecraft reached 132,000 km/h (82,000 mph; 37,000 m/s), and it came within 132,252 kilometers (82,178 mi) of the outer atmosphere of Jupiter. Close-up images of the Great Red Spot and the terminator were obtained. Communication with the spacecraft then ceased as it passed behind the planet. The radio occultation data allowed the temperature structure of the outer atmosphere to be measured, showing a temperature inversion between the altitudes with 10 and 100 mbar pressures. Temperatures at the 10-mbar level ranged from −133 to −113 °C (140 to 160 K; −207 to −171 °F), while temperatures at the 100 mbar level were −183 to −163 °C (90.1 to 110.1 K; −297.4 to −261.4 °F). The spacecraft generated an infrared map of the planet, which confirmed the idea that the planet radiated more heat than it received from the Sun.

Crescent images of the planet were then returned as Pioneer 10 moved away from the planet. As the spacecraft headed outward, it again passed the bow shock of Jupiter's magnetosphere. As this front is constantly shifting in space because of dynamic interaction with the solar wind, the vehicle crossed the bow shock a total of 17 times before it escaped completely.

• Jupiter encounter images
• 
  Jupiter as imaged by Pioneer 10
• 
  Jupiter close up as imaged by Pioneer 10
• 
  Ganymede as imaged by Pioneer 10
• 
  Europa as imaged by Pioneer 10
• 
  Crescent Jupiter as imaged by Pioneer 10

Deep space

Pioneer 10 crossed the orbit of Saturn in 1976 and the orbit of Uranus in 1979. On June 13, 1983, the craft crossed the orbit of Neptune, and so became the first human-made object to leave the proximity of the major planets of the Solar System. The mission came to an official end on March 31, 1997, when it had reached a distance of 67 AU (10.0 billion km; 6.2 billion mi) from the Sun, though the spacecraft was still able to transmit coherent data after this date.

After March 31, 1997, Pioneer 10's weak signal continued to be tracked by the Deep Space Network to aid the training of flight controllers in the process of acquiring deep-space radio signals. There was an Advanced Concepts study applying chaos theory to extract coherent data from the fading signal.

The last successful reception of telemetry was received from Pioneer 10 on April 27, 2002; subsequent signals were barely strong enough to detect and provided no usable data. The final, very weak signal from Pioneer 10 was received on January 23, 2003, when it was 12 billion km (80 AU; 7.5 billion mi) from Earth. Further attempts to contact the spacecraft were unsuccessful. A final attempt was made on the evening of March 4, 2006, the last time the antenna would be correctly aligned with Earth. No response was received from Pioneer 10. NASA decided that the RTG units had probably fallen below the power threshold needed to operate the transmitter. Hence, no further attempts at contact were made.

Timeline

Pioneer 10 and 11 speed and distance from the Sun

Heliocentric positions of the five interstellar probes (squares) and other bodies (circles) until 2030, with launch and flyby dates. Markers denote positions on 1 January of each year, with every fifth year labelled.
Plot 1 is viewed from the north ecliptic pole, to scale.
Plots 2 to 4 are third-angle projections at 20% scale.
In the SVG file, hover over a trajectory or orbit to highlight it and its associated launches and flybys.

Timeline of travel

Date Event 1972-03-03 Spacecraft launched 1972-06- Crossed orbit of Mars 1972-07-15 Entered the asteroid belt 1973-12 Start Jupiter observation phase Time Event 1973-12-03 Encounter with Jovian system 12:26:00 Callisto flyby at 1,392,300 km (865,100 mi) 13:56:00 Ganymede flyby at 446,250 km (277,290 mi) 19:26:00 Europa flyby at 321,000 km 22:56:00 Io flyby at 357,000 km 1973-12-04 02:26:00 Jupiter closest approach at 200,000 km 02:36:00 Jupiter equator plane crossing 02:41:45 Io occultation entry 02:43:16 Io occultation exit 03:42:25 Jupiter occultation entry 03:42:25 Jupiter shadow entry 04:15:35 Jupiter occultation exit 04:47:21 Jupiter shadow exit 1974-01-01 Phase stop 1974-01-01 Begin Pioneer Interstellar Mission More 1975-02-10 The US Post Office issued a commemorative stamp featuring the Pioneer 10 space probe (See image). 1983-04-25 Crossed orbit of Pluto (Pluto's irregular orbit meant it was closer to the Sun than Neptune). 1983-06-13 Crossed orbit of Neptune, the farthest planet away from the Sun at the time, to become the first human-made object to depart the Solar System. By dialing 1-900-410-4111, one could access a recording provided by TRW that was made by slowing down and converting Pioneer 10's data feed to analog sounds. 1997-03-31 End of mission. Contact is maintained with spacecraft to record telemetry. 1998-02-17 Voyager 1 overtakes Pioneer 10 as the most distant human-made object from the Sun, at 69.419 AU. Voyager 1 is moving away from the Sun over 1 AU per year faster than Pioneer 10. 2002-03-02 Successful reception of telemetry. 39 minutes of clean data received from a distance of 79.83 AU 2002-04-27 Last successful reception of telemetry. 33 minutes of clean data received from a distance of 80.22 AU 2003-01-23 Final signal received from the spacecraft. Reception was very weak and subsequent signals were barely strong enough to detect. 2003-02-07 Unsuccessful attempt to contact the spacecraft. 2006-03-04 Final attempt, again unsuccessful, to contact the spacecraft. 2023-07-18 Projections indicate that Voyager 2 overtook Pioneer 10 as the second farthest spacecraft from the Sun

Current status and future

Pioneer H, a backup unit, at the National Air and Space Museum.

On July 18, 2023, Voyager 2 overtook Pioneer 10, making Pioneer 10 the third-farthest spacecraft from the Sun after Voyager 1 and Voyager 2. As of July 2025, the probe is estimated to be 139.7 AU (20.9 billion km; 13.0 billion mi) from Earth and 139 AU (20.8 billion km; 12.9 billion mi) from the Sun. Sunlight takes 18.9 hours to reach Pioneer 10. The brightness of the Sun from the spacecraft is magnitude −16.0. Pioneer 10 is currently travelling in the direction of the constellation Taurus.

If left undisturbed, Pioneer 10 and its sister craft Pioneer 11 will join the two Voyager spacecraft and the New Horizons spacecraft in leaving the Solar System to wander the interstellar medium. The Pioneer 10 trajectory is expected to take it in the general direction of the star Aldebaran, currently located at a distance of about 68 light-years. If Aldebaran had zero relative velocity, it would require more than two million years for the spacecraft to reach it. Well before that, in about 90,000 years, Pioneer 10 will pass about 0.23 parsecs (0.75 light-years) from the late K-type star HIP 117795. This is the closest stellar flyby in the next few million years of all the Pioneer, Voyager, and New Horizons spacecraft, which are leaving the Solar System.

A backup unit, Pioneer H, is currently on display in the "Milestones of Flight" gallery at the National Air and Space Museum in Washington, D.C. Many elements of the mission proved to be critical in the planning of the Voyager program.

Pioneer plaque

Main article: Pioneer plaque

Pioneer plaque

Because it was strongly advocated by Carl Sagan, Pioneer 10 and Pioneer 11 carry a 152 by 229 mm (6.0 by 9.0 in) gold-anodized aluminum plaque in case either spacecraft is ever found by intelligent life-forms from another planetary system. The plaques feature the nude figures of a human male and female along with several symbols that are designed to provide information about the origin of the spacecraft. The plaque is attached to the antenna support struts where it would be shielded from interstellar dust.

Pioneer 10 in popular media

In the film Star Trek V: The Final Frontier, a Klingon Bird-of-Prey destroys Pioneer 10 as target practice.

In the serialized speculative fiction multimedia narrative 17776, one of the main characters is a sentient Pioneer 10.

In the 1995 video game Chaos Control, an alien encounter with Pioneer 10 initiates a conflict between the alien race and humanity.

See also

• Exploration of Jupiter
  • Pioneer 11, Jupiter and Saturn fly-by
  • Voyager 1 and Voyager 2, Jupiter fly-by en route to other outer Solar System fly-bys
  • Galileo, Jupiter orbiter
  • Cassini–Huygens, Jupiter fly-by for Saturn orbiter and Titan lander, respectively
  • New Horizons, Jupiter flyby en route to Pluto fly-by
  • Juno, Jupiter polar orbiter
  • Jupiter Icy Moons Explorer, Jupiter orbiter
  • Europa Clipper, Jupiter orbiter
• List of artificial objects leaving the Solar System
• List of missions to the outer planets
• Pioneer anomaly
• Robotic spacecraft
• Timeline of artificial satellites and space probes

References

Bibliography

• Angelo, Joseph A. (2007). Robot Spacecraft. Frontiers in Space. Facts on File Science Library. Infobase Publishing. ISBN 978-0-8160-5773-3.
• Burgess, Eric (1982). "Pioneer Odysseys". By Jupiter: Odysseys to a Giant. Columbia University Press. ISBN 978-0-231-05176-7.
• Burrows, William E. (1990). Exploring Space: Voyages in the Solar System and Beyond. Random House. ISBN 978-0-394-56983-3.
• Burrows, William E. (1999). This New Ocean: The Story of the First Space Age. Modern Library. Random House Digital, Inc. ISBN 978-0-375-75485-2.
• Dyer, Davis (1998). TRW: Pioneering Technology and Innovation since 1900. Harvard Business Press. ISBN 978-0-87584-606-4.
• Fimmel, Richard O.; van Allen, James; Burgess, Eric (1980). "Pioneer: First to Jupiter, Saturn, and Beyond" (PDF). NASA Special Publication. 446. Washington D.C., USA: NASA / Ames. ASIN B000IRXYN0. Bibcode:1980NASSP.446.....F. NASA-SP-446.
• Launius, Roger D. (2004). Frontiers of Space Exploration. Greenwood Press Guides to Historic Events of the Twentieth Century (2nd ed.). Greenwood Publishing Group. p. 36. ISBN 978-0-313-32524-3.
• Rogers, John Hubert (1995). The Giant Planet Jupiter. Practical Astronomy Handbook series. Vol. 6. Cambridge University Press. ISBN 978-0-521-41008-3.
• Simpson, J. A. (2001). "The Cosmic Radiation". In Johan A. M. Bleeker; Johannes Geiss; Martin C. E. Huber (eds.). The Century of Space Science. Vol. 1. Springer. p. 146. ISBN 978-0-7923-7196-0.
• Van Allen, James A. (2001). "Magnetospheric Physics". In Johannes Alphonsus Marie Bleeker; Arturo Russo (eds.). The Century of Space Science. Vol. 1. Springer. p. 155. ISBN 978-0-7923-7196-0.
• Wolverton, Mark (2004). The Depths of Space: The Story of the Pioneer planetary probes. National Academies Press. ISBN 978-0-309-09050-6.

External links

• Pioneer Project Archive Page Archived August 15, 2011, at the Wayback Machine
• Pioneer 10 Profile by NASA's Solar System Exploration
• NSSDC Pioneer 10 page
• Jupiter Odyssey (1974) is available for free viewing and download at the Internet Archive