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Mars Direct

RichardWSmith — Sat, 30 May 2026 08:27:34 GMT

Radiation Dose from Mars Direct Mission Plan: Fixed typo (incorrect decimal).

The beauty of Mars from 150 miles

Suitupshowup — Tue, 12 May 2026 11:44:35 GMT

Mars Direct

RichardWSmith — Sun, 10 May 2026 01:52:18 GMT

Advantages of This Mission: removed bullet on zero gee, as this now has its own section.

Long duration space flight

RichardWSmith — Sun, 10 May 2026 01:44:04 GMT

Cumulative Radiation Exposure: Adding Link

Mars Direct

RichardWSmith — Sun, 10 May 2026 01:43:04 GMT

Radiation Dose from Mars Direct Mission Plan: fixed link.

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 Robert Zubrin, working at the time at Martin Marietta felt that the plan was incoherent and got permission of his managers to build a cheaper, more practical plan.  Zubrin and another engineer David Baker worked on the Mars Direct plan, which would use local resources to create the fuel to return home, (greatly reducing the amount of mass to be sent to Mars).
-That year, Jim French published an idea in the Journal of the British Interplanetary Society suggesting that a fuel manufacturing plant be sent to Mars first.  However, the crewed space craft had to land within hose length of this factory, which was deemed too dangerous.  Zubrin came up with the idea of launching the return vehicle plus the fuel plant ahead of time.  If the crew could land within rover distance of the return vehicle (say 1000 km or closer), they could return.  Even better, they would have a fully refuelled return vehicle waiting for them before they left Earth.
+That year, Jim French published an idea in the Journal of the British Interplanetary Society suggesting that a fuel manufacturing plant be sent to Mars first.  However, the crewed space craft had to land within hose length of this factory, which was deemed too dangerous.  Zubrin came up with the idea of launching the return vehicle plus the fuel plant as one combined lander ahead of time.  If the crew could land within rover distance of the return vehicle (say 1000 km or closer), they could return.  Even better, they would have a fully refuelled return vehicle waiting for them before they left Earth.
 Baker suggested the name for this new mission plan: "Mars Direct".
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 Radiation damage to living beings is measured in Sieverts or rem.  (1 Sv = 100 rem.) See [[Radiation]] and [[Radiation shielding]] for more information.
-A prompt dose of 1 Sv might cause radiation sickness (some people won't notice anything).  2 Sv will cause radiation sickness in everyone.  At 3 Sv a prompt dose might cause death. At 5 Sv most people will die, unless they get care in a hospital.  Above 8 Sv, almost everyone will die, even with the best medical care.
+A prompt dose of 1 Sv might cause radiation sickness (a few people won't notice anything).  2 Sv will cause radiation sickness in everyone.  At 3 Sv a prompt dose might cause death. At 5 Sv most people will die, unless they get care in a hospital.  Above 8 Sv, almost everyone will die, even with the best medical care.
-In addition to short term effects, moderate doses of radiation cause long term health effects, which lower the maximum age you can reach (mostly from cancer).  The authoritative report: Biological Effects of Ionizing Radiation (BEIR) found that 0.1 Sv of radiation will cause a 1.8% chance of a fatal cancer within 30 years.  Now an average person has a 20% chance of dying of a fatal cancer, so if our Mars mission would get a total radiation dose of 50 mSv, then the chance of the astronaut getting a cancer rises from ~20% to 21%.
+In addition to short term effects, high to moderate doses of radiation cause long term health effects, which lower the average maximum age you can reach (mostly from cancer).  The authoritative report: Biological Effects of Ionizing Radiation (BEIR) found that 0.1 Sv of radiation will cause a 1.8% chance of a fatal cancer within 30 years.  Now an average person has a 20% chance of dying of a fatal cancer, so if our Mars mission would get a total radiation dose of 50 mSv, then the chance of the astronaut dying from cancer rises from ~20% to 21%.
 ===Radiation Dose from Mars Direct Mission Plan===
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 ! Mission Section !! Conjunction Mission !! Opposition Mission
 |-
-| Cosmic Rays in Transit || 318 mSv || 47.7 mSv
+| Cosmic Rays in Transit || 318 mSv || 477 mSv
 |-
 | Solar Radiation in Transit || 55 mSv || 96 mSv
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 ==Landing area==
-What is the best landing site?  A good answer to this question is the southern plains of Lunae Planum just north of Ophir Chasma (on the equator at 65° long W.). This places the base at an average elevation (between 6 and 7 km) and within a couple of thousand km’s of most of the scientifically interesting sites on Mars.
+What is the best landing site?  A good answer to this question is the southern plains of Lunae Planum just north of Ophir Chasma (on the equator at 65° long W.)  This places the base at an average elevation (between 6 and 7 km) and within a couple of thousand km’s of most of the scientifically interesting sites on Mars.
 ==Advantages of This Mission==

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-[[File:Brain terrain from around Mars 02.jpg|600pxr| Image shows the variety of different kinds of brain terrain on Mars. Brain terrain is called that because it resembles the surface of the human brain. It is thought to form when ice leaves the ground along cracks. ]]
+[[File:Brain terrain from around Mars 02.jpg|600pxr|Image shows the variety of different kinds of brain terrain on Mars. Brain terrain is called that because it resembles the surface of the human brain. It is thought to form when ice leaves the ground along cracks.]]
 Image shows the variety of different kinds of brain terrain on Mars. Brain terrain is called that because it resembles the surface of the human brain. It is thought to form when ice leaves the ground along cracks.<ref name=":0">Levy, J., J. Head, D. Marchant. 2009. Concentric crater fill in Utopia Planitia: History and interaction between glacial “brain terrain” and periglacial mantle processes. Icarus 202, 462–476.</ref> <ref name="Baker, D. 2015">Baker, D., J. Head. 2015. Extensive Middle Amazonian mantling of debris aprons and plains in Deuteronilus Mensae, Mars: Implication for the record of mid-latitude glaciation. Icarus: 260, 269-288.</ref>
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-[[File:Craters from around Mars 01.jpg |600pxr| different kinds of impact craters on Mars.]]
+[[File:Craters from around Mars 01.jpg|600pxr| different kinds of impact craters on Mars.]]
                                    Different kinds of impact craters on Mars.

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 Radiation does damage to living cells.  Prompt doses (which happen in a short time) are more dangerous than chronic doses which occur over a long time.  (Chronic doses give the body time to repair the damage, where as a prompt dose overwhelms the cellular repair.)
-Radiation damage to living beings is measured in Sieverts or rem.  (1 Sv = 100 rem.) See [[Radiation]] for more information.
+Radiation damage to living beings is measured in Sieverts or rem.  (1 Sv = 100 rem.) See [[Radiation]] and [[Radiation shielding]] for more information.
 A prompt dose of 1 Sv might cause radiation sickness (some people won't notice anything).  2 Sv will cause radiation sickness in everyone.  At 3 Sv a prompt dose might cause death. At 5 Sv most people will die, unless they get care in a hospital.  Above 8 Sv, almost everyone will die, even with the best medical care.
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 *The conjunction class mission, increases the amount of time spent on Mars, allowing more exploration and science to be done.
 *A radiation storm shelter will be provided to provide safety from a massive solar flare, if the crew is unlucky enough to experience one during the mission.
 *By choosing a travel time to Mars (about 6.5 months), the crew is on a 'free return' trajectory where if they choose NOT to land on Mars, they return to Earth exactly 2 years after launch.  This means that the Earth will be there, when they arrive back at Earth's orbit.  This increases safety, if for some reason they have to abort the landing.
 *The second Earth Return Vehicle (ERV) is launched on a slower trajectory, so if the crew can not land within 1,000 km of their own ERV, the second one can land beside them, with the pilot on Mars directing it down.  This improves safety.

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 ==Cumulative Radiation Exposure==
-The radiation received in the International Space Station is 144 milliSievert / year.  This is about 28% of the radiation dose of a 2.5 year Mars mission (assuming a mission where the total radiation exposure is 520 mSv over 2.5 years).  See the Mars Direct Mission, described in the "Case for Mars", by Robert Zubrin.
+The radiation received in the International Space Station is 144 milliSievert / year.  This is about 28% of the radiation dose of a 2.5 year Mars mission (assuming a mission where the total radiation exposure is 520 mSv over 2.5 years).  See the [[Mars Direct]] Mission, described in the "Case for Mars", by Robert Zubrin.
 This number does not mean much, but these values might give some perspective:

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 Mars Direct {{#tag:ref|{{cite journal|url="http://www.marspapers.org/paper/Zubrin_1991.pdf" |title=Mars Direct: A Simple, Robust, and Cost Effective Architecture for the Space Exploration Initiative|author=Robert Zubrin, David Baker, Owen Gwynne|date=1991 |accessdate=2017-09-02}}}} is a sustained humans-to-Mars plan developed by Dr. Robert Zubrin that advocates a minimalist, live-off-the-land approach to exploring the planet Mars, allowing for maximum results with minimum investment.  Using existing launch technology and making use of the Martian atmosphere to generate rocket fuel, extracting water from the Martian soil and eventually using the abundant mineral resources of the Red Planet for construction purposes, the plan drastically lowers the amount of material which must be launched from Earth to Mars, thus sidestepping the primary stumbling block to space exploration and rapidly accelerating the timetable for human exploration of the solar system.
 ==Overview of Mission Architecture==
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 After a year and a half on the Martian surface, the first crew returns to Earth, leaving behind the hab, the rovers associated with it and any ongoing experiments conducted there.  They land on Earth six months later to a hero’s welcome, with the next ERV/hab already on course for the Red Planet.  With two launches during each launch window – one ERV and one hab – more and more of Mars will be opened to human exploration.  Eventually multiple habs can be sent to the same site and linked together, allowing for the beginning of a permanent human settlement on the planet Mars.
 ==Landing area==