Pioneers 6, 7, 8, 9, E

by Hamish Lindsay with Dave Lozier (Pioneer 10 Flight Director)

The solar orbit interplanetary Pioneers were managed at Ames Research Center during the 1960s.

During the period from 1965 through 1969 a series of five spacecraft were launched from KSC. Four of the five were successfully inserted into orbits around the Sun with the fifth suffering a failure of the launch vehicle and thus was lost.

The Pioneer solar orbiters were a spin stabilized, solar cell powered, 150 lb. spacecraft. Scan: David Lozier.

Pioneers 6 – E were launched using the thrust augmented Delta with a third stage.

Pioneers 6, 7, 8, 9 and E were created to make the first comprehensive measurements of the solar wind, solar magnetic field and cosmic rays.

Designed to measure large scale magnetic phenomena and particles and fields in interplanetary space, data from the spacecraft were used to better understand stellar processes as well as the structure and flow of the solar wind.

The four spacecraft also acted as the world’s first space-based solar weather network, providing warning of solar storms which impact communications and power on Earth.

Pioneer 6 – 9 Spacecraft Operations Center Ames Research Center, Bldg 244, circa 1967. From left to right, two controllers, Charlie Hall, Norm Martin, Ralph Holtzclaw. Where are the PCs, the calculators, the cable video flat panel TVs, the internet and the wireless telephones? In the picture you can see the teletypes and a paper punch machine. The TTY is the internet of the time connected to the telephone line but only able to receive and print 3 characters per second. The paper punch machines punch holes that can be read later for final processing. The consoles (on the right) where Norm and Ralph are sitting contain voice lines to JPL and a telco black phone… the only telephone device available at the time. It may just have push buttons by this time but my guess it is a rotary dial. Scan and notes: David Lozier.

During the Apollo lunar landings, NASA used the fleet of Pioneers to provide hourly updates on the Sun’s activity to Mission Control in Houston. Their data guarded against the otherwise unexpected blast of intense showers of solar protons that could have endangered the lives of astronauts.

Pioneer 6-9 Apollo Solar Weather Coverage Ames Research Center May 1969. Look at that Friden calculator.... does division....wow! Photo: David Lozier.

Earth-Sun-line-fixed solar orbits and orbital elements for Pioneers 6,7,8,9 and E. Photo: David Lozier.

Detail of the orbital elements. Photo: David Lozier.

The four spacecraft, spin stabilised at 60 revolutions per minute, were launched into Solar orbits between 1965 and 1968. After their prime mission to study the Sun’s environment was completed, the spacecraft were then tracked only occasionally.

Pioneer 6 was launched on 16 December 1965 (02:31:20 EST night), one day after the successful Gemini VI/VII rendezvous.

Some time after 15 December 1995 (30 years after it was launched) the primary transmitter (TWT) failed. During a track on 11 July 1996 the spacecraft was commanded to switch to the backup TWT, and the downlink signal was re-acquired. The spacecraft and a few of the science instruments were again functioning.

Pioneer 6 held the record for the longest active spacecraft when Goldstone managed to lock on to its signal for about two hours on 8 December 2000 to commemorate its 35th anniversary.

Pioneer 7 was launched on 17 August 1966. (10:20:17 EST day) It was last tracked successfully on 31 March 1995. The spacecraft and one of the science instruments were still functioning. Pioneer-7 could only be tracked around perihelion because the electrical output from the solar array was degraded.

Pioneer 8 was launched on 13 December 1967 (09:08:00 EST day). Its primary transmitter (TWT) failed several years ago, but on 22 August 1996 the spacecraft was commanded to switch to the backup TWT, and the downlink signal was re-acquired. The spacecraft and one of the science instruments were again functioning.

Sometime in the early 90s Ames turned over control of Pioneer-8 to the JPL DSN for use as a radio source in the training of new station operators and spacecraft controllers.

Pioneer 9 was launched on 8 November 1968 (04:46:29 EST night). The spacecraft failed in 1983. Many attempts to contact Pioneer-9 after the last track in 1983 were never successful. On March 5, 1987 NASA declared the spacecraft lost.

Pioneer E, a fifth spacecraft in the series was launched on August 27, 1969 (17:59:00 EDT) but failed to reach orbit when, at 229 seconds into the flight, the launch vehicle was destroyed after a hydraulics line rupture on the main engine bell control system of the Delta.

People of the Pioneer Project

The Pioneer 9 launch crew, circa 1968. Ames Research Center photo A-41559. Scan: David Lozier.

The Pioneer 9 launch crew, circa 1968. 1. Charlie Hall (Pioneer Project Manager) 2. Charlie, Bob Hofstetter (Launch Vehicle Integration) 3. George Nothwang (Integration and Test Manager) 4. Al Wihelmi (Instrument Engineer), 5. Dave Lozier (Launch Vehicle and Trajectories) 6. Joe Lepitich (Instruments Manager) 7. Ralph Holtzclaw (Spacecraft Manager) 8. Bob Edens (Ground Data System Engineer). Click for a PDF version. Scan: David Lozier. Key: Colin Mackellar.

What is often overlooked is the fact that for Pioneers 8,9, and E, two spacecraft per launch were to be orbited.

Goddard, the Delta launch vehicle management center, came to the Pioneer Project and asked if they could include another small 40 lb payload on the rocket. It would be placed on the second stage down by the engine bell in a spring loaded deployment container. After second stage shutdown and separation from the third stage/Pioneer combination, a timed command to eject the TETR (Test and Training) would be executed. The small payload was intended to provide a radio beacon for the Apollo Tracking Network to test and train the station equipment and personnel.

Both TETRs for Pioneer 8 and 9 were successfully deployed but although the Delta-E for Pioneer E was equipped with a TETR, both spacecraft were lost when the launch vehicle failed.

Mike Dinn, in his recollections of the Honeysuckle Creek operation,s stated that the TETRs were never used because they had the Surveyors and the Lunar Orbiters radio links to train on before the Apollo missions were ever launched.

TETR B Satellite. (Image from the MSFN Technical Information Bulletin, Volume 5, Number 20, for October 15 1968.)

Pyramidal TETR deployment canister near engine bell and TETR spacecraft rendition (Dave Lozier in the back disinterested and looking at his fingers, Ugh.) – Photo and notes: Dave Lozier. :-)

Hamish Lindsay: From memory Honeysuckle Creek did track these spacecraft at various times. We tracked Pioneers 10 and 11 for many hours, particularly from 1974 when we joined the Deep Space Network until we closed down in 1981. Tidbinbilla continued tracking them until they ran out of consumables and began to drift.

In these days of sophisticated technology and high speed computers it is interesting to note that between 1964 to 1968 the spacecraft real-time data from the tracking stations was sent by teletype to twenty machines clattering away producing octal codes with a group of operators standing by converting the coded data with slide rules to plot the results. By the time Pioneer 10 appeared on the scene they had Xerox Sigma 5 computers generating the engineering and scientific data for the displays and recording on magnetic tapes.

Ames also had Sigma 5s to offline process telemetry tapes received from the tracking stations as well as real-time display of spacecraft and instrument health in the Pioneer Ops center.

Dave Lozier at the teletypes and the Sigma 5 at Ames Research Center circa 1973. Photo: David Lozier.

This stamp was produced to commemorate the Pioneer missions. Scan: Hamish Lindsay.