Interplanetary

Small Satellite Home Page - Established 1995

Interplanetary small-satellites list

Small-Satellites for interplanetary missions are difficult to classify in terms of mass, as their propulsion requirements generally drive the wet mass (i.e. fuelled spacecraft mass) of the spacecraft. Also the amount of fuel carried depends on the launcher injection orbit and the complexity of the mission. For the purposes of these pages, small interplanetary missions have been defined, as satellites with a wet mass less than 500kg.

This list is restricted to those satellites that made it onto the launcher, and is ordered in terms of launch date. For future interplanetary satellite missions, refer to the future missions page.

More...[small satellite classification]

Mariner 1, 1962

An interplanetary spacecraft launched on the 22nd July 1962 on an Atlas Agena B from Cape Canaveral. Its aim was to perform a Venus flyby and gather information on the Venusian atmosphere, its clouds and magnetic fields. Unfortunately the launcher had to be destroyed as it veered from its course. The spacecraft weighs 202kg measuring 3.04m long and 1.52m diameter, employing a tubular space structure with hexagonal base. A dish antenna and solar panels are extended from this. The solar panels carry gas jets at the ends for attitude control. A hydrazine engine was employed for manouevers. The structure holds an octagonal magnesium central module which houses the equipment. A wide and narrow field camera was flown and a cosmic ray telescope.

Mariner 2, 1962: A 202kg interplanetary spacecraft launched on the 27th August 1962 on an Atlas Agena B from Cape Canaveral. It had the same mission as Mariner 1, and flew by Venus at a distance of 34,830km, 109 days following trajectory injection from an Earth parking orbit. It provided a total of 35 minutes of detail. This included measuring the surface temperature to be higher than expected, at 428 degC, and concluded the atmosphere contained no water content. No breaks were observed in the clouds which were found to be mainly carbon dioxide. The magnetic field was found to be weak. Contact was finally lost on the 3rd January 1963. The Spacecraft was designed and operated by NASA JPL in the US. More...
[Mariner at JPL]; Picture (right) courtesy of NASA.

Mariner 3, 1964: A 261kg interplanetary spacecraft launched towards Mars on the 5th November 1964 on an Atlas Agena D from Cape Canaveral. Its aim was to take 21 pictures of Mars from 14,840km together with Mariner 4 , however the thermal protective shroud over the spacecraft and solar panels could not be shed and so desired trajectory was not achieved and the spacecraft missed Mars.

Mariner 4, 1964: The sister spacecraft of Mariner 3, a 261kg interplanetary spacecraft, was launched on the 28th November 1964 on an Atlas Agena D from Cape Canaveral. Despite the navigation system locking onto wrong stars, this problem was overcome soon along the trajectory, and the spacecraft flew by Mars at a distance of 9,844km, 228 days after leaving the Earth parking orbit. 21TV images were received, and a partial last 22nd image. These were the first close-up images of Mars, and showed a cratered world, with a much thinner atmosphere than predicted. It was largely concluded that Mars was geologically and biologically dead. Subsequent missions were diverted to Venus. The spacecraft was still shown to be operational 30 months later long after passing Mars.

Lunar Orbiter, 1966/7: A series of 5 lunar mapping missions launched on an Atlas Athena D between 1966 and 1967, following the successful Ranger series of spacecraft. The main purpose of the missions was to select a suitable equatorial landing site for the Surveyer and Apollo landers, but also to study the gravitational field, radiation and micrometeoroid environment. The table below describes the main mission parameters. The 390kg spacecraft employ a 1.6m high truncated cone, with four deployed panels measuring 5.6m span. Two cameras were carried weighing 65.8kg, comprising a wide field (80mm) and narrow field (610mm) lens. A mechanical shutter and quartz window was used, and 70mm film, which was scanned on-board and transmitted on the downlink. The spacecraft were three axis stabilised employing the sun and Canopus as a reference. Communications were via S-band empluing an omni and directional antenna. Each spacecraft was crashed at the end of the mission in order to asure a clean radio environment for subsequent orbiters.

[Lunar Orbiter program at NSSDC including many of the data sets]
Photo and data (table) courtesy of NASA NSSDC.

Pioneer 6, 7, 8, 9 and E, 1965-69

A series of interplanetary small satellites built by TRW for NASA Ames Research Center in order to measure large scale magnetic phenomena and particle fields in interplanetary space. All were launched on a THOR DELTA into a 0.8x 1.2 AU solar orbit, and were designed for 0.5 year life. The satellites structure was cylindrical Aluminium measuring 812mm long and 940mm in diameter, with three 1.8m magnetometer booms, also containing nutation dampers and orientation nozzles. A 1.32m mast on the cylinder end holds high and low gain antenna. The other end carries a dual frequency antenna, used in radio propagation experiments. The satellites were spin stabilised, and weighed 63.6kg. 79W of power was generated from the solar panels. The satellites were described as extremely simple, and formed the first space based solar weather network.
Pioneer E suffered a launch failure.

This series of spacecraft discovered the Earth's magnetic field tail away from the Sun. Simultaneous measurements from Pioneer 6 and 8 when they were 161 million km apart allowed the most accurate determination of the solar wind density to be made up to that point. In September 1972, Pioneer 7 was reactivated after being blocked by the Sun 312million km away.

[Ref TRW spacecraft guide].

Pioneer	Launched	Launcher
6	16 Oct 1965	THOR DELTA (DSV-3E)
7	17 Aug 1966	THOR DELTA
8 (C)	13 Oct 1967	THOR DELTA (DSV-3E)
9 (D)	8 Nov 1968	THOR DELTA (DSV-3E)
E	27 Aug 1969	THOR DELTA

Mariner 5, 1967: A 425kg interplanetary spacecraft launched on the 14th June 1967 on an Atlas Agena D from Cape Canaveral. Originally intended as the back-up spacecraft for Mariner 4, it was altered to fly by the Sun and Venus. The spacecraft solar panels were reversed and reduced in size. A thermal shield was also added. The spacecraft flew by Venus at a distance. distance of 3990km on the 19th October 1967. The surface temperature was now measured to be 267deg C, magnetic fields were measured to be only 1/3% of that of the Earth, and a weak ionosphere was detected above the atmosphere.

Mariner 6, 1969: A 413kg interplanetary spacecraft launched on the 24th January 1969 on an Atlas Centaur D from Cape Canaveral, with the mission to study Mars. The JPL NASA mission resulted in 201 images in combination with Mariner 7, when passing to within 3412km after 156 days.

Mariner 7, 1969: A 413kg interplanetary spacecraft launched on the 27th March 1969 on an Atlas Centaur from Cape Canaveral, to join Mariner 6 in its mission. It passed to within 3524km after 130 days. A few days before arrival antennas had to be switched, possibly due to a micrometeoroid strike.

Explorer 43, 1971: Explorer-43 was launched on the 13th March 1971. The second generation Interplanetary Monitoring Platform aimed to investigate the ralationship between Earth's and the Moon. The spacecraft weighed 288kg.

Apollo-P&F1 , 1971: A Particles and Fields experimetal scientific microsatellite weighing 36kg, was launched from the Apollo 15 spacecraft into lunar orbit on the 4th August 1971. The spacecraft measured the mass of the moon, and its gravitational field, the radiation environment, and the interaction of the Earth and moon's magnetic fields. The payload included a 1W S-band transponder, 48k bytes of magetic core memory, 25W solar panels, and transmitted data at 128bps. The satellite was hexagonal in shape with dimensions 355mm diameter x 787mm height. The satellite crashed into the moon after 6 months.

Apollo-P&F2, 1972: Particles and Fields experimetal scientific microsatellite weighing 36kg, was launched from the Apollo 16 spacecraft into lunar orbit on the 23rd April 1972 into an unintended plane. The spacecraft measured the mass of the moon, and its gravitational field, the radiation environment, and the interaction of the Earth and moon's magnetic fields. The payload included a 1W S-band transponder, 48k bytes of magetic core memory, 25W solar panels, and transmitted data at 128bps. The satellite was hexagonal in shape with dimensions 355mm diameter x 787mm height. The satellite crashed into mountains on the far side of the moon after 425 orbits on the 29th May 1972.

Explorer 47 (IMP-8): A 375.9kg mini-satellite launched on the 22nd September 1972. The Interplanetary Monitoring Platform measured interplanetary radiation, solar wind and energetic particles. More:...
[IMP-8 at GSPC]

Explorer 50, 1973: Explorer-50 was launched on the 25th October 1973. An interplanetary explorer to investigate the Earth's radiation environment. The satellite weighed 397.2kg.

Ulysses, 1990.: The 367kg Ulysses minisatellite was launched on the 6th October 1990 on the STS-41 mission with an inertial upper stage. It was placed into an interplanetary trajectory that would take it on a February 1992 flyby of Jupiter to place it into a 5.4x1.3AU heliocentric orbit.

Modern Small Interplanetary Missions

Muses-A (Hiten), 1990-007B.: A 185kg satellite launched on the 24th January 1990 from Kagoshima on an M3S2 launcher. The spacecraft released the Hagoromo sub-satellite in lunar orbit.

Hagoromo, 1990-007B.: A 12kg lunar sub-satellite on Muses A (Hiten), but contact was lost after its release on the 19th March 1990, possibly due to a tranmistter failure before its planned lunar swingby. The spacecraft was built by NEC for ISAS, and was launched on top of the 185kg Hiten spacecraft on an M3 launcher.

CLEMENTINE, 1994.: The Clementine minisatellite was launched on the 25th January 1994, with a mission to map the moon to much greater detail than ever achieved before, and to subsequently perform an astroid fly-by. The satellite was built at Naval Reseacrh Laboratories, and payloads integrated at the Air Force Phillips Laboratories. The mission proved extremely succesful in the lunar mapping phase, but the astroid fly-by had to be abandoned on its outbound journey due to failure of the propulsion system resulting in uncontrolled spin. It was concluded that fuel might have migrated back past valves.; More...[NRL][LASP]
Lunar Prospector, 1998-001A (25131): A Lockheed Martin built lunar mission for NASA under the Discovery program, was launched on the 5th January 1998 from Spaceport Florida on the first flight of the Athena-2 launch vehicle. The flight time to the moon was 105 hours, and it was placed into a 100km circular orbit. The 290kg (65kg dry?) satellite is cylindrical in shape and It is cylindrical in shape and measures 1.37m high and 1.22m in diameter, with three 2.4m booms. Its mission is to map the lunar surface composition, measure its gravity and magnetic fields, and to investigate the Clementine measurements seeming to indicate the existance of trapped ice on the lunar southern pole. For this reason the spacecraft carries a gamma ray spectrometer, magnetometer, electron reflectometer, a neutron spectrometer, and an alpha particle spectrometer.The spacecraft is spin stabilised, and carries no on-board computer. Instead, an hour delay line permits hour old telemetry to be interspersed with current telemetry, for when the spacecraft is out of view of the Earth. The satellite employed the LM100 bus and was built in 17 months, and the total mission cost is expected to be US$63m including launch and operations.; On the 5th March 1998, it was reported that the prospector had shown there to be water in ice form at both poles.
The polar lunar orbit was lowered on Dec 19 from 77 x 122 km to 25 x 55 km. Inclination remained at 90 degrees, and the updated lunar gravity model appears to remain accurate in this orbit. The orbit was then reduced to only 25 x 35 km on the 29th January 1999. Finally on the 31st July 1999 the spacecraft was deliberately crashed into a South Pole crater at 42.1E, 87.7S with the remainder of fuel, in an attempt to throw up a dust cloud which could have been observed by ground based observatories and might show up water vapour. No positive findings have been reported. The final orbit had the apogee raised to 230km.
More:[NASA NSSDC, NASA AMES, Lockheed Martin, NASA HQ, LANL][Masts at AEC-ABLE]; Cool: [Watch the telemetry here!]
Pictures courtesy of LM

Deep Space-1, 1998-061A: Developed by the prime contractor Spectrum Astro with JPL, under a US$139.5m (1996) contract within the NASA New Millenium project, in order to develop and test advanced technologies for interplanetary missions. It was launched on a DELTA 7326 into a 0.99x 1.32AU solar orbit inclined at 0.4 degrees on the 24th October 1998 with SedSat-1 as a piggyback payload. It employs the SA-200HP platform and will employ 12 new technologies including solar electric propulsion, carrying 81.5kg of Xe on the 486.3kg spacecraft, to perform a 5km fly-by of the near-Earth astroid McAuliffe in 1999 and comet West-Kohoutek-Ikemura in 2000, using a Mars gravity assist maneouver. It also carries 31.1kg of hydrazine. Amongst the other new technologies carried are solar array lens concentrators on 11.5m long arrays, delivering a total of 2600W. The concentraters employ cylindrical lenses to intensify the light levels onto the 3600 solar cells. A 3D computer intended for this spacecraft was delayed until a future mission. It is slated for launch on a DELTA-2-7326 (the first DELTA med-lite) in July 1998. The spacecraft will weigh 365kg. Other spacecraft in the Deep-Space series are being considered. Originally, problems were encountered with the ion thruster, but these were later overcome.

The spacecraft made its flyby of the astroid Braille on the 29th July 1999 at a distance of 15-25km, but failed to target its camera at time of closest approach, although IR imagery was returned. A later flyby of Borrely returned spectacular views. On the 18th December 2001 the spacecraft was retired. Its ion engine has been selected for the NASA Dawn mission.

More...

[artist impression][DS-1 at NASA][DS-1 at Spectrum Astro]
Pictures courtesy of Spectrum Astro

Stardust, 1999-003A (25618): A 350kg spacecraft in the Deep Space series being developed for NASA, launched on a 7 year trip towards the edge of the solar system and back, on a DELTA-2-7325 on the 7th February 1999. The spacecraft employs an Aerogel to capture and measure particles of space dust, from the 4km diameter comet Wild-2, astroids, and other objects. The capsule containing this will be recovered in 2006 for detailed chemical and isotopic analysis. The estimated project cost is $34m (1996). More...; [Stardust at JPL][Stardust at GSFC]

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