Along with the pair of rovers still active on the Martian surface (including Opportunity which has been on the move for over a decade now), NASA’s Mars 2020 Rover mission currently under development will continue the exploration of the Martian surface whose history stretches back to the Viking program which successfully placed a pair of landers on the surface four decades ago. While these Martian explorers are well known to most space enthusiasts today, their success is due in part to development work performed by NASA and its contractors a half a century or more ago. Among these earliest development programs was a little-known Mars lander concept known as the Automatic Biological Laboratory or simply ABL.
The Philco ABL Concept
During the 1960s, NASA performed studies of a number of potential Mars lander concepts for their second-generation planetary missions as part of the Voyager program. Not to be confused with NASA’s outer-planet explorers of the same name launched in 1977, the earlier Voyager program was meant to perform the second phase of planetary exploration after the initial reconnaissance performed by the Mariner program’s spacecraft in the 1960s and early-1970s. This Voyager series was to consist of orbiters carrying advanced landers to explore Venus and Mars during the 1970s. This incarnation of the Voyager program was cancelled in 1967 because of its increasing expense and eventually replaced by the relatively more modest Viking program to land on Mars. During the heyday of the Voyager program a half a century ago, probably one of the more advanced Mars lander development efforts, at least in terms of hardware built and tested, was the ABL developed by Philco Aeronutronic.
Just to familiarize the reader with this now unfamiliar company (and apologies in advance to those who get bored by corporate histories), Aeronutronic was originally founded in 1956 by the Ford Motor Company and was involved in a number of early space as well as defense projects. In 1961, Ford bought the bankrupt electronics manufacturer, Philco Corporation, which had been earlier contracted to build the tracking network for NASA’s Mercury program. In 1963, Ford merged their Aeronutronic and Philco’s aerospace-related divisions to create Philco Aeronutronic which continued to be NASA’s primary contractor for communications equipment during the 1960s including supplying the consoles used in the Manned Spacecraft Center in Houston, Texas. After Ford sold off many of Philco’s other divisions including its consumer electronics and appliance businesses until only the Aeronutronic divisions were left, Philco Aeronutronic was renamed Ford Aerospace and Communications Corporation in 1976 which was changed to simply Ford Aerospace Corporation in 1988. This company was sold off to Loral in 1990 to become the well known satellite manufacturer, Space Systems/Loral, which was subsequently purchased by the Canadian communications company, MacDonald, Dettwiler and Associates Ltd., in November 2012. Still with me?
Philco Aeronutronic received the contract to develop a Mars lander concept for Voyager in June 1964. Building on Ford Aeronutronic’s earlier experience developing the hard lander for NASA’s Block II Ranger lunar program (see “NASA’s First Moon Lander” for a full description of these missions), Philco in cooperation with the Jet Propulsion Laboratory designed a spherical lander with a diameter of 1.7 meters and a landed mass of about 540 kilograms – comparable in general size and mass to the Viking lander. Philco’s ABL had a densely-packed, integrated design with a 324-kilogram science payload. The science payload consisted of 61 kilograms of scientific instruments, 113 kilograms of samplers and sampling gear and 150 kilograms of experiment chemicals stored in torroidal tanks. A pair of 11-kilogram plutonium-fueled RTGs would supply a total of 140 watts to power ABL and help keep it warm in the cold Martian environment.
The exact mix of instruments on ABL evolved over the development of the project but included a panoramic camera, meteorological sensors, a mass spectrometer, gas chromatographs, an omnidirectional microphone, a water vapor detector, a polarimeter as well as ultraviolet, visible, and infrared spectrophotometers. Various life detection instruments were contemplated including a radioactive carbon dioxide analyzer, fluorometric instruments for enzyme detection, an amino acid analyzer, and photosynthetic activity detection chambers. An early object recognition system would also be included that would be capable of detecting motion in case some macroscopic Martian life forms moved past the lander.
Because of the time delay in communicating with Mars and the complex nature of the investigations that needed to be performed, direct commanding of ABL from Earth or the use of the relatively simple electromechanical sequencers like those employed by earlier lunar and planetary spacecraft to perform a predetermined series of tasks would prove impractical. Instead, ABL would employ a master computer to coordinate and command the individual tasks to be performed by the suite of scientific instruments and support equipment. The sequence of activities preprogrammed into the computer could be altered by ground command as needed to adapt to the situation at the landing site, compensate for system failures or take advantage of new findings as scientific investigations progressed.
The ABL Mission
Like the Viking landers, ABL would be encased in a protective aeroshell that would be released by the orbiting mother spacecraft and perform a deorbit burn to begin its descent towards the Martian surface. After the worst of the entry into the Martian atmosphere was completed, the aeroshell would be discarded and the lander would deploy a parachute. Unlike Viking which would use rockets for the final leg of the descent to the surface of Mars, Philco’s ABL would use a protective shell of balsawood to absorb the impact of the 150 meter per second landing just like the Block II Ranger lunar landers were suppose to do during their missions in 1962.
After touchdown, the protective shell would be discarded and the spherical lander would open petal-like panels to right itself and stabilize the capsule not unlike the somewhat smaller Soviet Mars landers launched in 1971 and 1973. Once upright, the ABL would deploy a central mast that held various sensors including the panoramic camera which would start transmitting images of the surroundings once contact had been established.
After the initial survey of the landing site was completed, ABL would go to work performing its experiments. Several means of securing samples for the various instruments were included in the ABL design. A core drill mechanism located on the ABL’s underside could collect samples up to 3 meters below the Martian surface. A sampler attached to an arm could gather samples to a depth of several centimeters within about a meter of the lander. An airborne sampler consisting of a boom extending from ABL’s side could also collect dust particles suspended in the Martian atmosphere. By far the most novel sample collecting mechanism included in the ABL design was a set of four remote samplers that traveled along guy wires running from ABL’s central mast. These guy wires would be deployed up to 300 meters from the lander using small rocket darts fired from ABL’s upper deck. The remote samplers would run along the guy wires and return samples from any point back to the lander for processing and analysis.
The ABL would continue its investigations from the surface of Mars for two Earth years performing a total of 35 experiment cycles – three for each of a dozen Martian “seasons”. This was done to characterize the seasonal changes in the Martian environment and its biological activity. Each experiment cycle would consume 1.4 kilograms of Martian surface material that would be gathered by the various sampler mechanisms. ABL would also collect and store 11 kilograms of pristine samples that could be retrieved by astronauts on future manned missions to Mars (whose presence would presumably release microorganisms into the environment which could taint future biological investigations of Mars).
The End of ABL
Philco Aeronutronic’s work on the development of ABL came to an end with the cancellation of the Voyager program in September of 1967. After three years of work including the building and testing of various ABL engineering models as well as conducting field experiments of the landing system, work on ABL was abandoned. Also contributing to the end of ABL was the realization that the Martian atmosphere was much thinner than had been earlier believed (for a full discussion of the changes in the scientific knowledge of the Martian atmosphere during this time, see “Zond 2: Old Mysteries Solved and New Questions Raised”). A landing on Mars employing only a parachute was simply impractical even for a robust, hard lander like ABL.
While the ABL design was abandoned, its development did contribute significantly to the design and eventual success of the Viking landers which reached Mars in 1976. While much of the work on ABL has been consigned to dusty archives or, worse yet, destroyed, one piece of the program managed to survive. A one-quarter scale model of ABL is on display at the New Mexico Museum of Natural History and Science in Albuquerque, New Mexico.
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“The New Search for Life on Mars”, Drew Ex Machina, May 25, 2014 [Post]
“Viking and The Question of Life on Mars, Part 1”, SETIQuest, Vol. 3, No. 3, pp. 1-6, Third Quarter 1997 [Article]
“Viking and The Question of Life on Mars, Part 2”, SETIQuest, Vol. 3, No. 4, pp. 1-7, Fourth Quarter 1997 [Article]
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