Between 1976 and 1978, a remarkably thorough student project at Purdue University garnered attention from NASA, the British Interplanetary Society, and the Jet Propulsion Laboratory. The project involved the design of a spacecraft with the purpose of extracting a 50-meter-long ice core from the southern polar ice cap of Mars. The ambitious goal was to obtain a historical record spanning millions of years, capturing insights into climate changes, volcanic eruptions, and, potentially, the existence of microscopic life on the red planet.
Mars, like earth, possesses ice caps at its northern and southern poles. These ice caps exhibit dynamic behavior, expanding and contracting in response to the changing seasons. On Earth, both permanent and seasonal polar caps consist entirely of water ice. However, on the colder Mars, winter temperatures lead to the condensation of carbon dioxide from the atmosphere at the winter pole. This results in a frost layer about a meter thick on the permanent water ice polar cap and surrounding areas. Covering slightly more than 1% of Mars's surface, these permanent caps are approximately three kilometers thick, while the seasonal caps at mid-winter extend from their respective poles to around 60° of latitude.
Confirmation that Mars's permanent polar caps primarily consist of water ice faced challenges. Initially observed in the 17th century, there was a widespread belief by the late 18th century that the caps were composed of water ice. However, data from the Mariner 4 spacecraft in 1965 suggested they were made of frozen carbon dioxide. Subsequent missions like Mariner 6, 7 (1969), and Mariner 9 orbiter (1971-1972) did little to contradict this interpretation.
In the late 1970s, information from the Viking orbiters finally confirmed that the northern permanent cap is composed of water ice. However, it wasn't until 2003, with new data from Mars Global Surveyor and Mars Odyssey orbiters, that the southern permanent cap's composition was similarly confirmed.
In the years when the composition of Mars's permanent caps was uncertain (1976-1977), a team of Purdue University School of Aeronautics and Astronautics students conducted a study on a Mars Polar Ice Sample Return (MPISR) mission. Their primary objective was to collect and return a 50-meter-long, five-millimeter-diameter ice core from Mars's southern permanent cap.
Assuming the caps on Mars were layered similarly to Earth, the students envisioned each layer containing a record of atmospheric particulates and climate conditions. This martian polar ice core, they believed, could provide insights into dust storms, asteroid impacts, volcanic eruptions, surface water, and the evolution of microbial life.
The proposed MPISR spacecraft would follow a Mars Orbit Rendezvous plan, akin to the 1974 Martin Marietta/Jet Propulsion Laboratory (JPL) Mars Sample Return (MSR) report. The spacecraft included a Viking-derived orbiter and lander. The orbiter would carry an Earth-Return Vehicle/Earth Orbit Vehicle (ERV/EOV), and the lander would feature an Ascent Vehicle (AV) for launching the polar ice sample into Mars orbit.
The mission's Earth departure date would be determined by the need for a short-duration flight from Mars to Earth and safe conditions for the lander at the south pole. The proposed launch date was 29 April 1986, utilizing the Space Shuttle Orbiter's payload bay. However, the Challenger accident in January 1986 dashed hopes about the Shuttle's capabilities.
The MPISR orbiter would arrive at Mars in November 1986, conducting mapping activities over 14 months to select a suitable south pole landing site. The lander would deploy an Ice Core Drill (ICD) to collect a 75-centimeter-long ice core over 90 days. The samples would then be launched into Mars orbit by the AV's rocket stages on 2 May 1988.
To ensure the ice core's preservation, the MPISR orbiter would dock with the AV third stage, transferring the sample container to the ERV/EOV. The ERV/EOV would depart Mars orbit on 27 July 1988, aiming for a 98-day return to Earth. After separation, the EOV would enter Earth orbit, and an automated Tug would retrieve it for transport to a Shuttle Orbiter or space station.
Despite its origins as a student project, Purdue's MPISR concept garnered significant interest and maintained relevance over the years. After a summary of the study appeared in the British Interplanetary Society's Spaceflight publication, two of its authors (Staehle and Skinner) even briefed JPL engineers on the concept in 1978.
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