Radiation dose
A radiation dose is the energy that radiation leaves in a body. The game counts it in millisieverts (mSv), once for a whole career and once for a sudden burst.
30 numbers, 21 with an outside source
- A0 numbers at grade A
- B15 numbers at grade B
- C3 numbers at grade C
- D3 numbers at grade D
- E9 numbers at grade E
Functionality
2 topics
Radiation
- Radiation is measured in mSv, and every hand carries two doses.
- The lifetime dose never goes down, and open space adds about two mSv a day to it.
- Past 1,000 mSv of lifetime dose, a hand asks to go ashore.
- A solar storm or a radiation belt gives an acute dose in a few hours.
- Past 1,000 mSv of acute dose a hand is radiation sick, so they fight worse.
- The body clears acute dose over weeks, and a sickbay or a hospital makes that faster.
- Each fixed layer of shielding halves a dose, so no shield removes it.
- A storm is halved by a thinner layer than the background.
- A storm is weaker far from the Sun.
- Every screen that quotes a dose also says what it means in years of permitted exposure.
Jupiter's moons
- Jupiter's moons are the exception, and they are not close.
- Io sits inside a trapped belt worth tens of thousands of mSv a day.
- Europa is thousands and Ganymede is tens.
- Callisto sits outside the belt and is quieter than open space.
Values
30 numbers: 15 B, 3 C, 3 D, 9 E
Each value is read from the game code. Sort by any column heading, or filter by grade or by a word.
| Quantity | Value | Grade | Source | Why this value |
|---|---|---|---|---|
| Open-space dose with no shielding | 1.84 mSv per day | BSecondary | Atomic Rockets, radiation, Galactic Cosmic Radiation (the Curiosity passage) | The page says Curiosity measured 1.84 millisieverts a day on the way to Mars, with no shielding, at the peak of the solar cycle. |
| Shielding that halves the cosmic-ray background | 18 g/cm^2 | BSecondary | Atomic Rockets, radiation, Trapped Radiation (the Jupiter shielding table), and Effectiveness of Shielding Materials for the 15 to 20 grams of water | The page's Jupiter shielding table gives one halving layer as 18 centimeters of liquid water, which is 18 grams per square centimeter; it also says 15 to 20 grams of water halves cosmic rays. |
| Shielding that halves a solar storm dose | 4.3 g/cm^2 | CDerived | Atomic Rockets, radiation, Effectiveness of Shielding Materials | The page says 20 grams per square centimeter of aluminum cuts the 1972 storm from 500 rem to 20 rem inside a command module, a cut of 25 times, which is one halving every 4.3 grams (20 divided by log base 2 of 25). |
| Solar events a year | 10 events | BSecondary | Atomic Rockets, radiation, Solar Energetic Particles (the gradual SPE passage) | The page, quoting NASA, says about 10 gradual solar particle events happen each year. |
| Years in one solar cycle | 11 years | BSecondary | Atomic Rockets, radiation, Galactic Cosmic Radiation (the Curiosity passage) | The page gives the solar activity cycle as 11 years, and its cosmic ray formula uses an 11 year sine. |
| Chance of an event on any one day | 0.0274 chance | CDerived | Atomic Rockets, radiation, Solar Energetic Particles (the gradual SPE passage) | The yearly count of events divided by 365.25 days; the count is the page's figure of about 10 a year. |
| Slope of the size law for events | 0.4 index | DAnalogy | Design notes: travel, Solar particle events as a size law (2026-09-28) | Gabriel and Feynman 1996 give a power law with a differential index of 1.2 to 1.4, so a cumulative index of 0.2 to 0.4, read here from the abstract through a web search; the paper itself was not opened. |
| Worst event, bare hull at 1 AU, once a cycle | 5,000 mSv | BSecondary | Atomic Rockets, radiation, Effectiveness of Shielding Materials | The page says the 1972 event was 5000 rem (50 sieverts) outside a ship and about 500 rem (5 sieverts) inside a command module. |
| Smallest event the size law draws | 0.0394 mSv | EAuthored | No source recorded | Solved from the size law so the worst event comes once in the number of events a solar cycle holds; the once a cycle rate is the game's choice, and the page names only the single 1972 event. |
| Exponent for how fast a storm weakens with distance from the Sun | 2 power of 1/R | DAnalogy | Design notes: travel, Solar particle events as a size law (2026-09-28) | The notes cite published fits of fluence against distance from the Sun, 1.4 to 2.7 and 2.1 plus or minus 0.3, all inside 1 AU; those papers were not opened for this grade, and the game extends the law outward with the inverse square. The sources are silent on this figure. |
| Nearest distance from the Sun the storm scale uses | 0.3 AU | EAuthored | No source recorded | The game chose a nearest distance so the storm scale is never computed deep inside the orbit of the innermost body; no source applies. |
| Annual limit the screens quote | 50 mSv | BSecondary | Atomic Rockets, radiation, Trapped Radiation (the Jupiter dose table), and the Chronic Radiation Syndrome Chart for the adult annual limit | The page gives the single-year limit as 50 millisieverts, and the annual limit for an adult as 0.05 sieverts. |
| Five-year limit the screens quote | 100 mSv | BSecondary | Atomic Rockets, radiation, Trapped Radiation (the Jupiter dose table) | The page gives the maximum five-year cumulative exposure as 100 millisieverts. |
| Lifetime dose at which a hand asks to go ashore | 1,000 mSv | BSecondary | Atomic Rockets, radiation, Observation (the ESA limit passage) | The page says the radiation limit for ESA astronauts is 1 sievert. |
| Acute dose at which a hand is radiation sick | 1,000 mSv | BSecondary | Atomic Rockets, radiation, Acute Radiation Syndrome Chart | The acute chart says mild symptoms begin to appear at 1 gray and become common at 2 gray; the game treats gray and sievert as equal for this radiation. |
| Acute dose the body clears each day | 35 mSv per day | CDerived | Atomic Rockets, radiation, Acute Radiation Syndrome Chart | The chart gives a latent phase of 10 to 14 days plus symptoms of up to 4 weeks for 1 to 2 gray, about 42 days, so a mid dose of 1.5 gray clears at about 36 millisieverts a day. |
| Time inside a belt per visit | 0.25 hours | EAuthored | No source recorded | The one authored number in the radiation model, chosen by the game as the time to approach, dock and leave a belt in one visit; no source gives it. |
| Morale lost each day while radiation sick | 4 morale per day | EAuthored | No source recorded | Chosen by the game to match the size and shape of the fatigue drain; the notes record no source for morale loss from sickness. |
| Acute dose bands (floor, grade, term) | 2,000, 6, radiation sickness, 1,000, 5, mild radiation sickness, 750, 4, nausea risk, 500, 3, immune impairment, 250, 2, subclinical, 50, 1, over annual limit, 0, 0, within annual limit mSv | DAnalogy | Atomic Rockets, radiation, Acute Radiation Syndrome Chart | The floors follow the chart's own steps (blood changes at 0.25 gray, immune impairment at 0.5, nausea risk at 0.75, symptoms at 1) and the annual limit; the grade numbers and clinical labels are the game's. |
| Io belt dose (read by getbeltdoseforvisit) | 36,000 mSv per day | BSecondary | Atomic Rockets, radiation, Trapped Radiation (the Jupiter dose table) | The page's Jupiter dose table gives Io 36 sieverts a day. |
| Europa belt dose | 5,000 mSv per day | BSecondary | Atomic Rockets, radiation, Trapped Radiation (the Jupiter dose table) | The page's Jupiter dose table gives Europa 5 sieverts a day. |
| Ganymede belt dose | 80 mSv per day | BSecondary | Atomic Rockets, radiation, Trapped Radiation (the Jupiter dose table) | The page's Jupiter dose table gives Ganymede 0.08 sieverts a day. |
| Callisto belt dose | 0.1 mSv per day | BSecondary | Atomic Rockets, radiation, Trapped Radiation (the Jupiter dose table) | The page's Jupiter dose table gives Callisto 0.0001 sieverts a day, outside the belt at 26.4 Jupiter radii. |
| Shielding of the RS-1 module | 2 g/cm^2 | EAuthored | No source recorded | Chosen by the game as the bottom rung of the shielding ladder; the notes name a real craft for the other rungs but none at this thickness. |
| Shielding of the RS-6 module | 25 g/cm^2 | BSecondary | Atomic Rockets, radiation, Observation (the storm shelter passage) | The page says a storm shelter can be as low as 25 grams per square centimeter and still keep astronauts out of serious risk. |
| Cut to daily fatigue and to a solar event's dose per point of Medical competence | 0.005 fraction per competence point | EAuthored | No source recorded | Chosen so that a medic reading the dosimeters gets people into the shelter. No source gives how much a medic cuts a dose. |
| Most the Medical department can cut daily fatigue and event dose | 0.5 fraction | EAuthored | No source recorded | Chosen so that no crew is ever spared a hard burn. |
| Acute dose one patient clears per day per point of Medical competence | 0.7 mSv per day per competence point | EAuthored | No source recorded | Chosen so that a rookie medic (competence 50) adds 35 mSv a day, which doubles natural recovery for one patient a day. The lifetime dose stays. No source gives a treatment rate. |
| The lifetime dose bands the screens name | 1,000, past the career limit, 100, over five years' permitted exposure, 50, over a year's permitted exposure, 0, inside a year's permitted exposure bands | EAuthored | No source recorded | The bands are the regulator limits already on this shelf (career, five-year, annual), never a symptom, because a slow dose makes nobody sick. The wording of each band is authored. |
| Areal density of real shelters that the module screen compares a number to | 25, a solar-storm shelter, 20, a planned lunar base, 15, the ISS storm cellar, 10, the Space Shuttle, 7, an Apollo command module, 0, little more than a suit g/cm^2 | BSecondary | Atomic Rockets, radiation, the passage comparing suit, Apollo, Shuttle, ISS and lunar base shielding | The mirror gives a suit at 0.25, an Apollo command module at 7 to 8, the Space Shuttle at 10 to 11, the ISS storm cellar at 15, planned lunar bases above 20, and a storm shelter as low as 25 g/cm^2. |
Real-world basis
8 points
- A dose is the energy that radiation leaves in a body, and the sievert is the unit that weighs the damage by the kind of radiation.
- A chronic dose builds up slowly and raises the chance of cancer, so it never heals.
- An acute dose lands in hours and burns tissue, so it can make a person sick but the body can heal it.
- In open space the dose is steady: Curiosity measured 1.84 mSv a day on the way to Mars, with no shielding.
- The danger is the solar storm: the 1972 event reached about 50 Sv outside a ship and 5 Sv inside a command module.
- Solar protons are easier to stop than cosmic rays, so a storm shelter of about 25 g/cm^2 makes a storm survivable.
- Jupiter's magnetic field traps particles, so a belt around Io gives about 36 Sv a day while Callisto sits outside it.
- A career limit of 1 Sv is the ESA astronaut limit, and the yearly limit for an adult is 50 mSv.
Game and reality differences
7 points
- Gray and sievert are treated as the same unit for this radiation.
- A belt visit counts as an acute dose, although the mirror files belts under chronic. A visit lasts a fraction of an hour, which is the mirror's own idea of acute.
- The time in a belt is the one authored number in the model. Three Io visits come to about one sievert by design.
- The clearing rate for acute dose is derived from the chart's recovery times, about six weeks for the 1 to 2 Gy band.
- The lifetime limit uses the ESA figure of 1 Sv. The NASA career table, which depends on age and sex, is not used.
- The captain carries no dose, and death at the LD50 level is not modeled.
- The mirror says a crew often gets warning of a storm. The game reports the dose after it lands.
Source absences
3 points
- Atomic Rockets does not provide values for the following:
- Clearing rate in mSv a day. The page gives recovery times in weeks and months for each acute band only.
- Storm size law past 1 AU. The outer system scaling is an extrapolation.
- Time a ship spends in a belt on a visit.
Sources
9 documents
- Atomic Rockets, radiation, Galactic Cosmic Radiation (Curiosity measurement): Curiosity measured 1.84 mSv a day on the trip to Mars from cosmic rays and solar storms, with no shielding. It flew at the peak of the 11-year solar cycle, when cosmic ray flux is relatively low. (all uses)
- Atomic Rockets, radiation, Radiation levels on the way to Mars: A round trip of 360 days in space and 500 days on the surface adds up to about 1.01 Sv. The ESA astronaut limit is 1 Sv. (all uses)
- Atomic Rockets, radiation, Solar storms: A shelter of about 25 g/cm^2 keeps astronauts out of serious risk, and 30 g/cm^2 of water is also called enough. Solar particles are easier to stop than cosmic rays. (all uses)
- Atomic Rockets, radiation, Space Radiation Risks: GCR vs SFE: One event in 1972, between Apollo 16 and 17, reached about 5,000 REM (50 Sv) outside a ship. About 20 g/cm^2 of aluminum cuts a 5 Sv dose inside a command module to 0.2 Sv. 15 to 20 g/cm^2 of water cuts the cosmic-ray dose to about half. (all uses)
- Atomic Rockets, radiation, Gradual SPEs (NASA text): About 10 gradual solar particle events happen each year. They are erratic, run for days, and usually follow a visible coronal mass ejection, so a crew often has warning. (all uses)
- Atomic Rockets, radiation, Trapped Radiation (Jupiter dose table): Dose a day: Io 36 Sv, Europa 5 Sv, Ganymede 0.08 Sv, Callisto 0.0001 Sv. Callisto lies at 26.4 Jupiter radii, outside the belt. The single-year limit is 50 mSv and the five-year limit is 100 mSv. (all uses)
- Atomic Rockets, radiation, Chronic Radiation Syndrome Chart: The annual limit for an adult is 0.05 Sv. (all uses)
- Atomic Rockets, radiation, Acute Radiation Syndrome Chart: Mild acute symptoms appear from 1 Gy and become common near 2 Gy, after a latent phase of 10 to 14 days. The fatality rate in the 1 to 2 Gy band is about 10%, and LD50 is near 4.5 Gy. (all uses)
- Atomic Rockets, radiation, Acute and chronic exposure (paragraph beginning 'There are two kinds of radiation exposure'): Acute damage heals with time, and chronic damage gradually builds up over a lifetime. Chronic dose raises the cancer risk decades later. "acute radiation damage will heal. Chronic damage does not." (all uses)