In the 1960s , there was great optimism about the future of space exploration. NASA had just achieved a series of successes, including the moon landing in 1969 , giving the impression that by then man could also easily reach other planets in our solar system. In this context, many experts believed that man would have set foot on Mars by 1985 :
As early as 1965 – years before the first moon landing – NASA’s Marshall Space Flight Center (MSFC) was speculating on the task of possible astronauts on Mars. Earlier still, around 1962, the US Space Agency had commissioned a preliminary scientific study – the EMPIRE study program undertaken by the Aeronutronics Division of the Ford Motor Company for the Future Design Office, Marshall Space Flight Center, under the NAS8 Contract -5025 – aimed at verifying the various possibilities of possible future manned interplanetary missions directed towards Mars or Venus. Still today, in the digitized version of NASA documents, the system proposed by the Italian pioneer of astronautics Gaetano Arturo Crocco is also mentioned during the VII International Astronautical Congress , held in Rome in 1956. [source] In the old study, they were put into discussion of hypothetical two-planet flyby missions of the Crocco and Symmetrical trajectory classes :
The Crocco mission with a launch window of August 1971 requires an interplanetary injection velocity increase of 10.1 km/sec, has a return velocity of 13.5 km/sec, and takes about 400 days. The Symmetric mission with a July 1970 launch window has an injection velocity boost of 5.3 km/sec, a return velocity of 15.8 km/sec, and lasts approximately 630 days. Additional results of trajectory studies and disruption trajectories are reported. The guidance and navigation subsystem,
intermediate fixes and planetary approach fixes are discussed.
A detailed analysis of the EMPIRE reentry phase includes consideration of an Apollo-type, Drag Brake, and hoist-type reentry vehicle to return the six-man crew to mission completion or an aborted condition. The High L/D reentry vehicle is used in the missions considered. The various technology areas required for the design criteria are developed and different spacecraft designs are considered. The all-chemical propulsion Crocco system is ultimately scrappeddue to weight, complexity and cost. The nuclear-injected Crocco gets a similar treatment. The most convenient of the methods turns out to be the energy injection method which for the symmetrical mission leads to the feasibility of a nuclear-injected vehicle with a weight in Earth orbit of about 180,000 kilograms (400,000 lbs) before interplanetary transit. Furthermore, two symmetric chemical vehicles are treated. Conservative radiation exposures are derived, for the 630-day mission, of less than 200 REM, and a polyethylene radiation shelter is designed. The scientific aspects of the missions are discussed:
Mission success probabilities are presented for the various missions considered and for the Saturn C-5, Nova and Super-Nova Earth launch vehicles in light of possible development. The need to accelerate nuclear rocket engine developments and auxiliary power developments is indicated. The definition of a larger nuclear engine on the order of 200,000 lbs of thrust and about 800 seconds of endurance or 50,000 lbs of thrust and 3600 seconds of endurance is given for the symmetrical mission in 1970 (energy requirements are higher in 1972 and for the next launch due to the less favorable position of Mars). At the time, researchers recommended the immediate development of this advanced nuclear propulsion capability.a total program cost of $12.6 billion regardless of other planned research and development costs. In conclusion, the technological feasibility for a first manned Mars-Venus double planet flyby is believed to be demonstrated in this study . At the time, NASA had identified several areas for accelerated development and experimental confirmation of the theory. Necessary funding and development of Nova or Saturn C-5 orbital operations capability is required. The 1970 launch window appeared to offer the least expensive symmetrical mission for several years in the 1980s . In this hypothetical context – it is reported in a study published on the web in 2021– The Avco/RAD extended mission crew would see 42 men occupy three 14-man surface bases for 300 days while four men would remain aboard an orbiting command module. Further missions would even include possible exploration of Phobos and Deimos , the natural satellites of Mars, and testing for possible signs of microbial life . Below is the list of missions rejected by both NASA and other space agencies around the world:
Proposal by Wernher von Braun (from 1947 to 1950):
Wernher von Braun was the first to make a detailed technical study of a mission to Mars. [1] [12] The details were published in his book Das Marsprojekt (1952, published in English as The Mars Project in 1962 [81] ) and in several subsequent works. [82] Willy Ley popularized a similar mission in English in the book The Conquest of Space (1949), with illustrations by Chesley Bonestell . Von Braun’s Mars project called for the launch of nearly a thousand three-stage vehicles from Earth to carry parts for the Mars mission to be built in an Earth-orbiting space station. [12] [83] The mission itself called for a fleet of ten spacecraft with a combined crew of 70 to Mars, carrying three winged surface excursion vessels that would land horizontally on the surface of Mars. (The winged landing was considered possible because at the time of its proposal, the Martian atmosphere was believed to be much denser than it was later discovered.)
In the revised 1956 vision of the Project Mars plan, published in the book The Exploration of Mars by Wernher Von Braun and Willy Ley, the size of the mission was reduced, requiring only 400 launches to put two ships together, still carrying a winged landing vehicle . [84] Later versions of the proposed mission, featured in Disney’s “Man In Space” film series, [85] featured nuclear -powered ion propulsion vehicles for interplanetary cruise.
US proposals (1950s to 1970s):
From 1957 to 1965, General Atomics worked on Project Orion , a proposal for a nuclear pulse propulsion spacecraft . Orion was to have the ability to carry extremely large payloads compared to chemical missiles, making manned missions to Mars and the outer planets possible. One of the first vehicle designs was intended to send an 800-ton payload into Mars orbit. The Partial Nuclear Test Ban Treaty of 1963 made further development impractical, and work was completed in 1965. [86] In 1962, Aeronutronic Ford, [87] General Dynamics and the Lockheed Missiles and Space Company studied Mars mission plans as part of the NASA Marshall Spaceflight Center’s “Project EMPIRE.” [12] These studies indicated that a mission to Mars (possibly including a flyby of Mercury and Venus) could be accomplished with the launch of eight Saturn Vsboosters and assembly in low Earth orbit, or possibly with a single launch of a hypothetical “post-Saturn” heavy vehicle. While the EMPIRE missions were never proposed for funding, they were the first detailed analyzes of what it would take to make a human journey to Mars using actual NASA spaceflight data, setting the stage for future studies, including significant mission studies by TRW, North American, Philco, Lockheed, Douglas and General Dynamics, along with several internal NASA studies. [12] After the success of the Apollo program , von Braun supported a manned mission to Mars as the focal point for NASA’s manned space program. ThereVon Braun’s proposal used Saturn V boosters to launch NERVA- powered upper stages that would propel two six-member spacecraft on a dual mission in the early 1980s. The proposal was considered by President Richard Nixon , but passed in favor of the Space Shuttle . In 1975, von Braun discussed the mission architecture that emerged from these Apollo-era studies in a taped lecture, and while doing so he suggested that multiple shuttle launches could instead be configured to lift the two spacecraft equipped with nuclear thermal rocket engine in smaller parts, for assembly in orbit. [89]
Soviet mission proposals (1956 to 1969):
The Martian Piloted Complex (MPK) was a proposal by Mikhail Tikhonravov of the Soviet Union for a manned Mars expedition, using the (then proposed) N1 rocket, in studies from 1956 to 1962. The Soviets sent many probes to Mars with some known success stories, including entering Mars’ atmosphere, but the overall success rate has been low. (see Mars 3 ) Heavy Interplanetary Spacecraft (known by its Russian acronym TMK) was the designation of a Soviet space exploration proposal in the 1960s to send a manned flight to Mars and Venus (project TMK-MAVR) without landing. The TMK spacecraft was to launch in 1971 and make a 3-year flight including a Mars flyby, at which time the probes would be launched. The project was never completed because the required N1 rocket never flew successfully. The Mars Expeditionary Complex , or “‘MEK”‘ (1969) was another Soviet proposal for a Mars expedition that would take a crew of three to six to Mars and back with a total mission duration of 630 days.
Case for Mars (1981-1996):
After the Viking missions to Mars, between 1981 and 1996, several conferences called Case for Mars were held at the University of Colorado at Boulder . These conferences supported human exploration of Mars, presented concepts and technologies, and held a series of workshops to develop a basic concept for the mission. He proposed the use of in situ resource utilization to produce rocket fuel for the return trip. The mission study was published in a series of volumes of proceedings. [90] [91] Subsequent conferences presented alternative concepts, including Robert Zubrin and David Baker’s “Mars Direct” concept; the proposal “On the trail of Mars” by Geoffrey A. Landis , [92] who proposed intermediate steps before the Mars landing, including human missions to Phobos; and Lawrence Livermore National Laboratory ‘s “Great Exploration” proposal , among others.
NASA Space Exploration Initiative (1989):
In response to a presidential initiative, NASA studied a plan for human lunar and Martian exploration as a follow-up proposal to the International Space Station. This led to a report, called the 90-day study , [93] in which the agency proposed a long-term plan to complete the Space Station as “a critical next step in all our space efforts,” back to the Moon and establish a permanent base and then send astronauts to Mars. This report was widely criticized as too elaborate and expensive, and all funding for human exploration beyond Earth’s orbit was canceled by Congress.
Why man has not been to Mars in the 70-80s:
First, space exploration, rather than impractical, turned out to be simply very expensive. Too expensive, even for the United States of America which in the 70s and 80s significantly reduced their investment budget due to the reduction of interest in the conquest of space (their main competitor, the Soviet Union , was changing rapidly and with Gorbachev in command of the USSR, Moscow took on a gradually less competitive attitude towards Washington, prompting the Americans to focus on other things). Second, Mars is much further from Earth than the Moon, and the technical challenges of getting there are much greater. Despite these obstacles, the exploration of Mars continues. NASA plans to send a manned mission to Mars by 2030, and other nations, such as China and the United Arab Emirates , are also developing programs to explore the red planet. It’s possible that humans will finally set foot on Mars within the next few decades, but it’s also possible that it will take even longer.
Sources:
https://ntrs.nasa.gov/citations/19650082475
https://history.nasa.gov/monograph21/Chapter%203.pdf
https://it.wikipedia.org/wiki/Crocco_Grand_Tour
https://arc.aiaa.org/doi/abs/10.2514/6.1966-2006
https://www.wired.com/2012/04/manned-mars-surface-missions-1966/
https://en.wikipedia.org/wiki/List_of_crewed_Mars_mission_plans
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