Mars Direct - Revision history

RichardWSmith: /* Radiation Dosage */ fixed grammar

2026-06-09T17:28:16Z

Radiation Dosage: fixed grammar

RichardWSmith: /* Radiation Dosage */ Added link, and more information.

2026-06-09T17:27:50Z

Radiation Dosage: Added link, and more information.

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

2026-05-30T08:27:34Z

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

RichardWSmith: /* Radiation Dosage */

2026-05-30T08:21:53Z

Radiation Dosage

RichardWSmith: /* Radiation Dosage */ Fixed wording / made more accurate.

2026-05-18T17:03:21Z

Radiation Dosage: Fixed wording / made more accurate.

RichardWSmith: /* Landing area */ fixed punctuation.

2026-05-15T20:34:33Z

Landing area: fixed punctuation.

RichardWSmith: /* History of Development */ made sentence clearer.

2026-05-15T20:25:35Z

History of Development: made sentence clearer.

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

2026-05-10T01:52:18Z

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

RichardWSmith: /* Radiation Dosage */ added link.

2026-05-10T01:49:35Z

Radiation Dosage: added link.

RichardWSmith: /* Radiation Dose from Mars Direct Mission Plan */ fixed link.

2026-05-10T01:43:04Z

Radiation Dose from Mars Direct Mission Plan: fixed link.

@@ Line 28: / Line 28: @@
 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]], [[Radiation sickness]] and [[Radiation shielding]] for more information.
+Radiation damage to living beings is measured in Sieverts or rem.  (1 Sv = 100 rem.) See [[Radiation]], [[Radiation sickness]], and [[Radiation shielding]] for more information.
 A prompt dose of 1 Sv will usually cause radiation sickness (a few people won't notice anything).  2 Sv will cause radiation sickness in everyone, and could cause death in people in poor health.  At 3 Sv a prompt dose might cause death in healthy individuals.  The dose at 4 Sv is normally lethal with no medical treatment.  At 5 Sv most people will die, unless they get care in a hospital.  (Massive effort, such as bone marrow transplants and massive efforts to prevent any disease bacteria from reaching the patient have seen occasional survivors up to 8 Sv.)  Above 8 Sv, almost everyone will die, even with the best medical care, and 10 Sv is considered universally lethal.

@@ Line 28: / Line 28: @@
 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]] and [[Radiation shielding]] for more information.
+Radiation damage to living beings is measured in Sieverts or rem.  (1 Sv = 100 rem.) See [[Radiation]], [[Radiation sickness]] and [[Radiation shielding]] for more information.
-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.
+A prompt dose of 1 Sv will usually cause radiation sickness (a few people won't notice anything).  2 Sv will cause radiation sickness in everyone, and could cause death in people in poor health.  At 3 Sv a prompt dose might cause death in healthy individuals.  The dose at 4 Sv is normally lethal with no medical treatment.  At 5 Sv most people will die, unless they get care in a hospital.  (Massive effort, such as bone marrow transplants and massive efforts to prevent any disease bacteria from reaching the patient have seen occasional survivors up to 8 Sv.)  Above 8 Sv, almost everyone will die, even with the best medical care, and 10 Sv is considered universally lethal.
 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%.

@@ Line 48: / Line 48: @@
 ! 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

@@ Line 30: / Line 30: @@
 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, 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%.

@@ Line 32: / Line 32: @@
 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.
-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===

@@ Line 69: / Line 69: @@
 ==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==

@@ Line 10: / Line 10: @@
 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".

@@ Line 82: / Line 82: @@
 *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.

@@ Line 59: / Line 59: @@
 |}
-So we would expect 0.52 Sv for the entire mission.  This is less than several cosmonauts have experienced on the Mir space station, and there are no reported radiation effects.  See [[Long Duration Space Flight]].
+So we would expect 0.52 Sv for the entire mission.  This is less than several cosmonauts have experienced on the Mir space station, and there are no reported radiation effects.  See [[Long duration space flight]].
 ==Zero Gravity on Mars Direct Mission==