#228 - Chris Welch - Mars Month 3 - Human Missions

"Imagine yourself in a spaceship millions of miles from Earth. You see the same people every day. The Earth, with all it means to you, is just another bright star in the heavens; you aren’t sure you’ll ever get back to it. Every noise about the rocket ship suggests a breakdown, every crash a meteor collision"
Werner Von Braun, Collier’s series April 30th, 1954)

Robert Goddard at 17 was Inspired by HG Wells and according to his diary, on October 19, 1899, Goddard climbed a cherry tree in his backyard and ‘imagined how wonderful it would be to make some device which had even the possibility of ascending to Mars…when I descended the tree, existence, at last, seemed very purposive”

Across the Atlantic in Europe Kurd Lasswitz inspired the young Wernher von Braun and Walter Hohmann, who asked himself, ‘How do you get up there?’

People started to think about a rocket journey more seriously after the major breakthrough during the war, the V2, made by Von Braun, who kept aiming for mars, but kept hitting London, Incident 337 narrowly missing the current BIS headquarters. Then Shepphard, Cleaver in the Bis had published the first unclassified nuclear mission to Mars 1948, and Ross one of the first spacesuit and space stations.

Arthur Clarke’s The Sands of Mars (1951) set around the year 2000 uses the atomic-powered Ares to fly to Mars, taking three months, built on the designs suggested by the JBIS rocketry papers, and explored in his own non-fiction studies. Ares is

launched from ‘Space Station One’ designed as a point of transfer between chemical-rocket planetary ferries and atomic-powered interplanetary ships (atomic rockets being

banned from Earth’s atmosphere). Similarly, Phobos was developed as a docking station at Mars

The science from the Mariner 4 1964 showed a cold moonlike landscape, and much less desirable the momentum for post-Apollo Mars programmes was quickly lost

Spiro Agnew’s Space Task Group in 1969 suggested a nuclear-rocket mission to Mars as early as the 1980s, $8bn a year by the late 1970s it was abandoned, in favour of building the Space Shuttle.

Scientists, however, started to realise that Mars could be far more inviting and potentially was once wet, and maybe there was still exciting discoveries to be made. After the dissolution came new hope. Sci-Fi again, Kim Stanley Robinson was looking at the new technology and his designs used Space shuttle tanks, gone was the nuclear propulsion, we had drop tanks as habs and space trucks

1990 also saw engineer Zubrin start to make himself known. President George H.W. Bush’s made the ‘Space Exploration Initiative’ of 1989, a forward-looking programme for American spaceflight. NASA’s made ‘Ninety-Day Study’, and the scheme had Earth-orbital facilities, lunar orbital stations and surface bases, and, finally, 1000-tonne spaceships bound for Mars. Zubrin referred to this $450bn scheme as ‘Battlestar Galactica’, in response Zubrin presented ‘Mars Direct’: ‘the plan allows us to accomplish a manned Mars mission with what amounts to a lunar-class transportation class system’ … the trick was ISRU to manufacture rocket propellant in situ on Mars, almost certainly inspired by a short JBIS paper James French, published in 1989. Zubrin estimated that Mars Direct would be 10% the cost of NASA’s design.

Mars Direct was featured in Brian de Palma movie Mission to Mars (2000), and NASA researcher Geoffrey A. Landis’s award-winning book Mars Crossing (2000). exceptionally well informed and the story of a Mars-Direct programme gone wrong, think revenant set on Mars. A trace of sulphur radicals in the Martian dirt wrecks the crew’s ERV fuel system. The story is flagging that Zubrin’s plans are perhaps not quite watertight

Von Braun

Reading / Watching Material

Project Mars, a Technical Tale (by WvB) (written in 1949, but published only in 2006. Original German version remains unpublished). However, its technical appendix was published in 1952 (DE) 1953 (EN)

  • This appendix alone is a "technically comprehensive design" for a human expedition to Mars. "the most influential book on planning human missions to Mars" according to Annie Platoff

  • Collier’s series of popular articles, running between 1952 to 1954, in particular, “Can we get to Mars? (April 30, 1954) - Awesome Illustrations.

  • Man in Space - Disney+ Featuring von Braun and Willy Ley (1955)

  • Eyes on the Red Planet: Human Mars Mission Planning 1952-1970 (Annie Platoff, Johnson Space Center Ref: NASA/CR-2001-208928)

  • Born on 23 March 1912, in the town of Wirsitz, Germany

  • In 1930, von Braun joined the Spaceflight Society (Verein für Raumschiffahrt or "VfR") and assisted Willy Ley in his liquid-fueled rocket motor tests in conjunction with Hermann Oberth.

  • Spaceflight Society Founded in 1927 (Ley one of the founders)

  • Von Braun is for many the most influential figure in the history of Human Mars Mission Planning

  • His plans go big, inspired by Polar expeditions, and need government support.

“Since the development of the long-range liquid rocket, it has been apparent that true space travel cannot be attained by any back-yard inventor, no matter how ingenious he might be. It can only be achieved by the coordinated might of scientists, technicians, and organizers belonging to nearly every branch of modern science and industry.” Von Braun explained that a mission to Mars would require a fleet of ships, noting that if Columbus had sailed with only one ship rather than a fleet of three ships he might never have made it back to Spain with news of his discoveries. “So it is with interplanetary exploration: it must be done on a grand scale.”

For reference, publication in 1954, before Sputnik

  • Two and half year total duration (8 month travel in each direction, more than a year on Mars, 15 months aproximatelly)

  • 355,000,000 miles (571.3 million km). Hohmann transfer to Earth-to Mars trajectory.

  • 70 Crew Members

  • Chemical Propulsion

  • The fleet would use a nitric acid/hydrazine propellant that, although corrosive and toxic, could be stored without refrigeration during the three-year round-trip to Mars

  • 5,583 tons of nitric acid and alcohol propellants to place about 40 tons of cargo into orbit, so a total of 5,320,000 tons of propellants in total

  • Carry everything, no ISRU (In Situ Resource Utilization)

  • 10 “Massive space ships” - 4000 tons each - Assembled in Earth orbit using materials supplied by 950 launches of three-stage reusable heavy-lift winged launch vehicles

3 of of the 10 Ships will have torpedo shaped noses and huge wings

  • The other 7 Passenger ships made with girders and spheres without streamlining and inflatable fabric propellant tanks and personnel spheres.

  • First achieve orbit, then land

  • From Mars orbit, they would turn telescopes toward Mars’ equator to select a site for a surface exploration base camp.

  • First landing ship will be assembled in Mars Orbit (Torpedo nose + Wings + Landing “Skis”). Landing to take place in the polar caps because he expects a smooth surface.

  • That landing crew will then travel 4000 miles to the equator (6400 km) over Martian land. First rocket plane abandoned at the pole.

  • Main expedition at the equator, runway to be built for rest of the crew to land on the other “rocket planes”

  • Rocket planes to be stripped of their wings and landing gear, then set on their tails and back to rendezvous with the orbital vehicles to head back to Earth.

  • This would take place in a century from then, the 2050s

  • Von Braun emphasises on dangers and acknowledgement of how many elements are still unknown and that he counts on those elements being researched and understood in the future. He realizes that many assumptions will become obsolete, but he wants to discuss the problems of a mission to Mars in terms of “what was known at the time”.

  • Focus on “Man” (Human) being the weakest link. Focus on Medicine and Psychological unknowns. (Confinement, hatred that could lead to murder!). Mentions muscle atrophy, and proposes spring exercise machines (as we have in the ISS today) or “Synthetic Gravity” (i.e. rotation/centrifugal). Mentions that crew must be entertained. Focus on the importance of crew selection (1 in 6000 qualified physically, mentally and emotionally, not counting education).

  • Focus on radiation, proposes surrounding cabin crews with the fuel tanks. Hopes for a radiation “pill”.

  • Counts on “unmanned” exploration first to clarify unknowns

  • Focus on dangers of “micrometeoroids” , one of the reasons to have multiple ships in the expedition. (Not mentioned but one can imply he is thinking of them as bullets and some crew might die). Holes to be plugged.

  • Worries about cleanliness of air, but also that it should not be too clean. Fry egg example with acrolein.

  • Thinks that distance will be too far for TV signal. Recommends censorship on radio entertainments.

  • Hibernation! In 100 years who knows.

  • In 1975, von Braun discussed the mission architecture that emerged from these Apollo-era studies in a recorded lecture and while doing so suggested that multiple Shuttle launches could instead be configured to lift the two Nuclear Thermal Rocket engine equipped spacecraft in smaller parts, for assembly in-orbit

Dan Goldin became NASA Administrator on April 1, 1992, officially abandoning plans for near-term human exploration beyond Earth orbit with the shift towards a "faster, better, cheaper" strategy for robotic exploration

Top 4 Risks going to Mars

(1) space radiation health effects of cancer, cardiovascular disease, and cognitive decrements (2) Spaceflight-Associated Neuro-ocular Syndrome (3) behavioral health and performance decrements, and (4) inadequate food and nutrition

Zubrin Detail

  • While working at Martin Marietta designing interplanetary mission architectures, Robert Zubrin perceived a fundamental flaw in the Space Exploration Initiative (SEI).

  • Zubrin said of NASA's plan was to fully utilize as many technologies as possible as “The exact opposite of the correct way to do engineering”

  • Zubrin's alternative

  • longer surface stay,

  • faster flight-path in the form of a conjunction class mission,

  • in situ resource utilization

  • The craft launched directly from the surface of Earth to Mars as opposed to be being assembled in orbit or by a space-based drydock.

  • Marietta, put together a 12-man team within the company focused primarily on more traditional mission architectures,

  • Zubrin and colleague David Baker's "use local resources, travel light and live off the land" became the hallmark of Mars Direct

Mission Profile

First launch

Ares rocket (grrrr ...naming): to boost the first flight of the uncrewed Earth Return Vehicle (ERV)

  • Heavy-lift booster of similar size to the Saturn V, derived from Space Shuttle components like the Advanced Solid Rocket Boosters, a modified shuttle external tank, and a new Lox/LH2 third stage for the trans-Mars injection of the payload.

  • Ares could put 121 tonnes into a 300 km circular orbit, and boost 47 tonnes toward Mars

  • ERV The upper stage comprises the living accommodation for the crew during their six-month return trip to Earth from Mars. The lower stage contains the vehicle's rocket engines and a small chemical production plant.

  • Once there, over ten months, the Sabatier reaction coupled with electrolysis would be used to combine the hydrogen with the carbon dioxide of the Martian atmosphere to create up to 112 tonnes of methane and oxygen. This relatively simple chemical-engineering procedure was used regularly in the 19th and 20th centuries and would ensure that only 7% of the return propellant would need to be carried to the surface of Mars.

  • 96 tonnes of methane and oxygen would be needed to send the Earth Return Vehicle on a trajectory back home at the conclusion of the surface stay; the rest would be available for Mars rovers.

  • Would signal the successful production of chemicals required for operation on the planet and the return trip to Earth

Second launch (a little over 2 years after the first launch)

  • After the signal, the Mars Habitat Unit would be launched on a 6-month long low-energy transfer trajectory to Mars,

  • Carrying a crew of four astronauts (the minimum number required so that the team can be split in two without leaving anyone alone).

  • During the trip, artificial gravity would be generated by tethering the Habitat Unit to the spent upper stage of the booster and setting them rotating about a common axis. This rotation would produce a comfortable 1 g working environment for the astronauts, freeing them of the debilitating effects of long-term exposure to weightlessness.

  • Landing and surface operations

  • The upper stage would be jettisoned, with the Habitat Unit aerobraking into Mars orbit before soft-landing in proximity to the Earth Return Vehicle.

  • The precise landing would be supported by a radar beacon started by the first lander.

  • The crew would spend 18 months on the surface, carrying out a range of scientific research, aided by a small rover vehicle carried aboard their Mars Habitat Unit, and powered by the methane produced by the Earth Return Vehicle.

  • Return

  • Leaving the Mars Habitat Unit for the possible use of subsequent explorers.

  • On the return trip to Earth, the propulsion stage of the Earth Return Vehicle would be used as a counterweight to generate artificial gravity for the trip back.

  • Follow-up missions would be dispatched at 2-year intervals to Mars to ensure that a redundant ERV would be on the surface at all times, waiting to be used by the next crewed mission or the current crew in an emergency. In such an emergency scenario, the crew would trek hundreds of kilometres to the other ERV in their long-range vehicle.

The Mars Habitat Unit

  • 2- or 3-deck vehicle providing a comprehensive living and working environment for a Mars crew

  • individual sleeping quarters which provide a degree of privacy for each of the crew and a place for personal effects.

  • communal living area, a small galley, exercise area, and hygiene facilities with closed-cycle water purification.

  • The lower deck of the Mars Habitat Unit provides the primary working space for the crew: small laboratory areas for carrying out geology and life science research; storage space for samples, airlocks for reaching the surface of Mars, and a suiting-up area where crew members prepare for surface operations.

  • Protection from harmful radiation while in space and on the surface of Mars would be provided by a dedicated "storm shelter" in the core of the vehicle.

  • include a small pressurized rover that is stored in the lower deck area and assembled on the surface of Mars. Powered by a methane engine,to extend the range astronauts can explore to 320 km.

Zubrin and Baker pitched Mars Direct at the Marshall Spaceflight Center in April 1990 reception was very positive. A tour culminated in a demonstration at the National Space Society they received a standing ovation.

Resistance to the plan came from teams within NASA working on the Space Station and advanced propulsion concepts who rejected Mars Direct. Zubrin did not give up.

After being granted a small research fund at Martin Marietta, Zubrin and his colleagues successfully demonstrated an in-situ propellant generator which achieved an efficiency of 94%.

In November 2003, Zubrin was invited to speak to the U.S. Senate Committee on the future of space exploration. Two months later the Bush administration announced the creation of the Constellation program, a human spaceflight initiative with the goal of sending humans to the Moon by 2020. While a Mars mission was not specifically detailed, a plan to reach Mars based on utilizing the Orion spacecraft was tentatively developed for implementation in the 2030s. In 2009 the Obama administration began a review of the Constellation program, and after budgetary concerns, the program was cancelled in 2010

There are a variety of psychological and sociological issues that could affect long-duration expeditionary space missions. Early human spaceflight missions to Mars are expected by some to have significant psycho-social problems to overcome, as well as provide considerable data for refining mission design, mission planning, and crew selection for future missions

Since it was first proposed as a part of Mars Direct, the Mars Habitat Unit has been adopted by NASA as a part of their Mars Design Reference Mission, which uses two Mars Habitat Units – one of which flies to Mars uncrewed, providing a dedicated laboratory facility on Mars, together with the capacity to carry a larger rover vehicle. The second Mars Habitat Unit flies to Mars with the crew, its interior given over completely to living and storage space.

To prove the viability of the Mars Habitat Unit, the Mars Society has implemented the Mars Analogue Research Station Program (MARS), which has established a number of prototype Mars Habitat Units around the world.


Since Mars Direct was initially conceived, it has undergone regular review and development by Zubrin himself, the Mars Society, NASA, Stanford University and others.

Mars Semi-Direct

  • Zubrin and Weaver developed a modified version

  • This mission consists of three spacecraft and includes a "Mars Ascent Vehicle" (MAV).

  • The ERV remains in Mars orbit for the return journey, while the uncrewed MAV lands and manufactures propellants for the ascent back up to Mars orbit.

  • When subjected to the same cost-analysis as the 90-day report, Mars Semi-Direct was predicted to cost 55 billion dollars over 10 years, capable of fitting into the existing NASA budget.

  • Mars Semi-Direct became the basis of the Design Reference Mission 1.0 of NASA, replacing the Space Exploration Initiative.

Design Reference Mission

The NASA model, referred to as the Design Reference Mission, on version 5.0 as of September 1, 2012, calls for a significant upgrade in hardware (at least three launches permission, rather than two), and sends the ERV to Mars fully fueled, parking it in orbit above the planet for subsequent rendezvous with the MAV.

Mars Direct and SpaceX

  • Zubrin has posited a dramatically lower cost human Mars mission using hardware developed by SpaceX.

  • The crew of two would be sent to Mars by a single Falcon Heavy launch, the

  • Dragon spacecraft acting as their interplanetary cruise habitat.

  • Additional living space for the journey would be enabled through the use of inflatable add-on modules if required.

  • Artificial Gravity with a tether between the Dragon habitat and the TMI (Trans-Mars Injection) stage acting to allow rotation of the craft.

  • The Dragon's heatshield characteristics could allow for a safe descent if landing rockets of sufficient power were made available. Research at NASA's Ames Research Center has demonstrated that a robotic Dragon would be capable of a fully propulsive landing on the Martian surface

  • On the surface, the crew would have at their disposal two Dragon spacecraft with inflatable modules as habitats, two ERVs, two Mars ascent vehicles and 8 tonnes of cargo.


Other Studies

The Mars Society and Stanford studies retain the original two-vehicle mission profile of Mars Direct but increase the crew size to six.

Mars Society Australia developed their own four-person Mars Oz reference mission,

  • based on Mars Semi-Direct. This study uses horizontally landing, bent biconic shaped modules, and relies on solar power and chemical propulsion throughout

  • where Mars Direct and the DRMs used nuclear reactors for surface power and, in the case of the DRMs for propulsion as well.

  • The Mars Oz reference mission also differs in assuming, based on space station experience, that spin gravity will not be required.

Mars Analogue Research Stations

The Mars Society has argued the viability of the Mars Habitat Unit concept through their Mars Analogue Research Station program. These are two or three decked vertical cylinders ~8 m in diameter and 8 m high. Mars Society Australia plans to build its own station based on the Mars Oz design.The Mars Oz design features a horizontal cylinder 4.7 m in diameter and 18 m long, with a tapered nose. A second similar module will function as a garage and power and logistics module.

Mars Direct has featured on a Discovery Channel programs Mars: The Next Frontier in which issues were discussed surrounding NASA funding of the project, and on Mars Underground, where the plan is discussed more in-depth.


"Mars to Stay" proposals involve not returning the first immigrant/explorers immediately, or ever. It has been suggested the cost of sending a four or six-person team could be one fifth to one-tenth of the cost of returning that same four or six-person team. Depending on the precise approach taken, a quite complete lab could be sent and landed for less than the cost of sending back even 50 kilos of Martian rocks. Twenty or more persons could be sent for the cost of returning four

ESA Plans for mars do not include Humans

The Aurora programme is no longer active for archival. The Agency's current Human and robotic exploration strategy for Mars

  • ExoMars trace gas orbiter — now

  • ExoMars rover and drill — launching 2022, landing 2023

  • Mars Sample Return:

  • The first element, NASA Perseverance, rover — currently on Mars

  • ESA’s Earth Return Orbiter, Sample Fetch Rover and Transfer Arm — by 2026

  • The landing of first martian samples on Earth — 2031

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