Published on January 16, 2008
Slide1: PIONEER 1 & 2 SPACECRAFT Slide2: PIONEER 1 IN SYSTEM LEVEL TEST AT TRW Slide3: Pioneer 1 on a Thor-Able launch vehicle ready for blast-off to the moon, on Oct. 11, 1958. Pioneer 0,1, and 2 were the Unites States’ first lunar attempts. These identical spacecraft all failed to meet their lunar objectives. Slide4: Smaller than the previous Pioneers, Pioneer 3 and 4 each carried only a single experiment to detect cosmic radiation. Both vehicles were planned to flyby the moon and return data about the Earth and Moon's radiation environment. The launch of Pioneer 3 failed when the launch vehicle first's stage cut-off prematurely. Although Pioneer 3 did not achieve escape velocity, it reached an altitude of 102,332 km and discovered a second radiation belt around Earth. The launch of Pioneer 4 was successful, and Pioneer 4 was the first American spacecraft to escape Earth's gravitational pull as it passed within 58,983 km of the moon (about twice the planned flyby altitude). The spacecraft did return data on the Moon radiation environment, although the desire to be the first man-made vehicle to fly past the moon was lost when the Soviet Union's Luna 1 passed by the Moon several weeks before Pioneer 4. Slide5: The Pioneer spacecraft itself was designed for high reliability using space-proven components. TRW Systems designed and fabricated the two Jupiter spacecraft, Pioneers F and G, at their Redondo Beach, California, facility. Slide6: <> Conceptual drawing of the Pioneer 10 & 11 spacecraft showing the location of all the primary components. Slide7: PHOTO OF THE PLAQUE MOUNTED ON THE PIONEER 10 AND 11 SPACECRAFT Slide8: The Jupiter mission by Pioneer 10 needed the highest-yet launch velocity of a spacecraft, actually the highest velocity of any manmade object, over 51,500 km (32,000 miles) per hour. This was achieved with an Atlas-Centaur launch vehicle, to which was added a solid propellant third stage. The launch vehicle boosted the spacecraft in direct ascent, i.e., with no parking orbit, to start the flight to Jupiter at about 51,500 km (32,000 mi.) per hour. A trip of just under 600 days was the shortest time to Jupiter within the capabilities of the launch vehicle, and a trip of 748 days' the longest. Slide9: LAUNCH OF PIONEER 10 BY AN ATLAS CENTAUR ROCKET FROM KENNEDY SPACE CENTER; MARCH 3, 1972 Slide10: PLANET SATURN AS VIEWED BY PIONEER 11 IN SEPT. 1979 Slide11: PART OF SATURN’S RING SYSTEM AS VIEWED BY PIONEER 11 IN SEPT. 1979 MOON Slide12: JUPITER WITH A SHADOW OF MOON IO AS VIEWED BY PIONEER 10 IN DEC. 1973 Moon Shadow Slide13: POLAR REGION OF JUPITER AS VIEWED BY PIONEER 10 IN DEC. 1973 Slide14: The first encounter trajectory with Jupiter was chosen to probe into the radiation belts and ensure that the spacecraft would have opportunities to obtain images of the terminator, the Great Red Spot, and several satellites, and would go into occultation behind lo as seen from Earth. Slide15: The Pioneer mission to Jupiter consisted of several phases of spacecraft operations: near launch, interplanetary, and encounter. The interplanetary phase continued after encounter with Jupiter. If the first Pioneer survived its encounter with Jupiter, the second spacecraft could be directed to a flyby that would hurtle it afterwards towards Saturn for a two-planet mission. Slide16: Pioneer Spacecrafts 10 & 11 Extended Mission Slide17: Communication with the Pioneer spacecraft at unprecedented distances relies upon the large antennas of the Deep Space Net, such as this one at Goldstone in California's Mojave Desert. Slide19: Pioneer 1 consisted of a thin cylindrical midsection with a squat truncated cone frustrum on each side. The cylinder was 74 cm in diameter and the height from the top of one cone to the top of the opposite cone was 76 cm. Along the axis of the spacecraft and protruding from the end of the lower cone was an 11 kg solid propellant injection rocket and rocket case, which formed the main structural member of the spacecraft. Eight small low-thrust solid propellant velocity adjustment rockets were mounted on the end of the upper cone in a ring assembly which could be jettisoned after use. A magnetic dipole antenna also protruded from the top of the upper cone. The shell was composed of laminated plastic. The total mass of the spacecraft after vernier separation was 34.2 kg, after injection rocket firing it would have been 23.2 kg. The spacecraft was powered by nickel-cadmium batteries for ignition of the rockets, silver cell batteries for the television system, and mercury batteries for the remaining circuits. Radio transmission was at on 108.06 MHz through an electric dipole antenna for telemetry and doppler information at 300 mW and a magnetic dipole antenna for the television system at 50 W. Ground commands were received through the electric dipole antenna at 115 MHz. The spacecraft was spin stabilized at 1.8 rps, the spin direction was approximately perpendicular to the geomagnetic meridian planes of the trajectory. Slide20: On the plaque a man and woman stand before an outline of the spacecraft. The man's hand is raised in a gesture of good will. The physical makeup of the man and woman were determined from results of a computerized analysis of the average person in our civilization. The key to translating the plaque lies in understanding the breakdown of the most common element in the universe - hydrogen. This element is illustrated in the left-hand corner of the plaque in schematic form showing the hyperfine transition of neutral atomic hydrogen. Anyone from a scientifically educated civilization having enough knowledge of hydrogen would be able to translate the message. The plaque was designed by Dr. Carl Sagan and Dr. Frank Drake and drawn by Linda Salzman Sagan. Slide21: Launched on 2 March 1972, Pioneer 10 was the first spacecraft to travel through the Asteroid belt, and the first spacecraft to make direct observations and obtain close-up images of Jupiter. Famed as the most remote object ever made by man through most of its mission, Pioneer 10 is now over 7.6 billion miles away. (On 17 February 1998, Voyager 1's heliocentric radial distance equaled Pioneer 10 at 69.4 AU and thereafter exceeded Pioneer 10 at the rate of 1.02 AU per year.) Pioneer 10 made valuable scientific investigations in the outer regions of our solar system until the end of its science mission on 31 March 1997. The Pioneer 10 weak signal continued to be tracked by the DSN as part of an advanced concept study of communication technology in support of NASA's future interstellar probe mission. The power source on Pioneer 10 finally degraded to the point where the signal to Earth dropped below the threshold for detection in its latest contact attempt on 7 February, 2003. Pioneer 10 will continue to coast silently as a ghost ship through deep space into interstellar space, heading generally for the red star Aldebaran, which forms the eye of Taurus (The Bull). Aldebaran is about 68 light years away and it will take Pioneer over 2 million years to reach it. After more than 30 years, it appears the venerable Pioneer 10 spacecraft has sent its last signal to Earth. Pioneer's last, very weak signal was received on 23 January 2003. NASA engineers report that Pioneer 10's radioisotope power source has decayed, and it may not have enough power to send additional transmissions to Earth. NASA's Deep Space Network (DSN) did not detect a signal during the last contact attempt on 7 February 2003. The previous three contacts, including the 23 January signal, were very faint, with no telemetry received. The last time a Pioneer 10 contact returned telemetry data was 27 April 2002. NASA has no additional contact attempts planned for Pioneer 10. Slide22: The extended mission for Pioneer was to search for the heliopause. The heliopause is the meeting surface of the solar wind and the medium outside the solar environment where the region of interstellar space begins. The solar wind is a 1,600,000 km-per-hour (1,000,000 mph) flow of gases expelled by the sun consisting of protons, electrons, and other subatomic particles. The interstellar medium is of uncertain composition, but the interstellar winds are known to include energetic atomic nuclei whose cosmic flux is detected as far inward as the Earth. An artist's conception of the heliospheric boundaries, (click on the image to the right for a larger version) shows the other spacethat have joined Pioneer 10 and 11 in this search. We can see that only Pioneer 10 is moving in the opposite direction to the Sun's motion through the galaxy, shown here as the solar apex direction. The motion of the heliospheric boundary through the local interstellar medium may cause a bow wave upstream of the heliopause and a tail downstream. The flow of subatomic particles making up the solar wind is expected to undergo a shock transition from supersonic to subsonic before reaching the heliopause. This shock is called the solar-wind termination shock. Here termination refers to the end of supersonic flow and not the end of the solar wind, which occurs at the heliopause. Prior to Pioneers 10 and 11, the effect of the solar wind was thought to extend to the vicinity of Jupiter or perhaps a bit farther. The Pioneer scientists now predict the distance from the Sun at which the terminal shock may be encountered is from 60 to 100 astronomical units (AU) or more, where an AU is defined as the distance of the Earth from the sun ~ 150 million kilometers (~93,000 million miles). For reference, the distance to the outermost planet is ~ 40 AU's.