Timeline for What thickness/depth of water would be required to provide radiation shielding in Earth orbit?
Current License: CC BY-SA 3.0
32 events
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| Feb 17, 2023 at 23:08 | comment | added | Slarty | An interesting idea, but I suspect that if Starship comes up to expectations it will be capable of taking its own water - cheap to reuse and capable of lifting 100-150 tonnes to low earth orbit (spin launch can manage 200kg). | |
| Feb 17, 2023 at 3:05 | comment | added | Keith Reynolds | @Slarty Yup. Spinlaunch platform throws up a rocket with apayload to near orbit. Then the rocket fires in the second phase, but is itself a single stage rocket. My main point was that water ice payload inside the rocket (figuratively buckets) could be spinlaunched to space comparitivly cheaply and used for shielding, or Rather than use massive rockets to get a massive deep space rocket and rocket fuel to orbit for a deep space mission. Spinlaunch watet to orbit, process into fuel, and in orbit transfer the the rocket fuel to smaller rockets launched from the ground intended for deep space, | |
| Sep 28, 2022 at 21:07 | comment | added | Slarty | @Keith Reynolds spinlaunch only acts as the first stage of propulsion. To get to orbit the spin launched payload has to be attached to a "second" stage rocket | |
| Nov 13, 2021 at 23:11 | comment | added | Keith Reynolds | Just recently oct 22 2021 spinlaunch test flung a suborbital 'rocket' tens of thousands of feet up with a centrifuge. Pure conjecture but I see potential to relativly cheaply fling ice up for constructing spacecraft shielding and a refueling station in low earth orbit to process some of the ice to hydrogen and oxygen. | |
| May 4, 2019 at 16:01 | comment | added | MolbOrg | "1 mSv/hr" - background radiation number seems not correct, it more like annual dose 1.26mSv, hourly doses on level of 0.1-0.18 uSv (10^-6 Sv), not sure if it affects any other number statement in the post, maybe need revaluating for that | |
| Jun 29, 2018 at 20:56 | comment | added | Magic Octopus Urn | I'm wondering more about cosmic rays and water's effects on those, because those are the more damaging to humans; correct? | |
| Feb 27, 2018 at 12:24 | comment | added | Martin Schröder | How long would that water last? I assume some of it is changed to heavy or tritiated water over time. | |
| Oct 11, 2016 at 9:50 | comment | added | Jason Goemaat | @LocalFluff It depends on how much damage is acceptable. Spending 1/2 your time shielded would still mean 40 days total exposure for an 80 day trip. | |
| S May 5, 2016 at 18:55 | history | suggested | CommunityBot | CC BY-SA 3.0 |
'exponentially' implies a mathematical exponential relationship between the mass of the fuel needed to escape LEO and #of launches. This isnt the case as described, however, one only needs about 2x the fuel required to get some mass to LEO. That's a linear relationship not exponential
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| May 5, 2016 at 18:50 | review | Suggested edits | |||
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| S Apr 20, 2016 at 17:35 | history | edited | Nathan Tuggy | CC BY-SA 3.0 |
MathJax + removing pointless vestige of previous rhetoric
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| S Apr 20, 2016 at 17:35 | history | suggested | David T. Svarrer | CC BY-SA 3.0 |
There was a calculation error, where the cylinder volume calculation had become 4 times bigger, in that the original calculation stated DIAMETER squared times pi times cylinder height, while, it is in actual sense the RADIUS which is squared, then times pi, and cylinder height / [email protected]
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| Apr 20, 2016 at 12:39 | review | Suggested edits | |||
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| Sep 1, 2015 at 16:43 | comment | added | Ellesedil | This What If? article by Randall Munroe goes into detail about the "effects" of swimming in a nuclear spent fuel pool. It's a great read for people asking these kinds of questions. | |
| Mar 7, 2015 at 21:38 | vote | accept | James Jenkins | ||
| Nov 23, 2014 at 10:27 | comment | added | NPSF3000 | @LocalFluff and if we could make the shielding directional we might be able to reduce that down to ~2 tons. | |
| Nov 21, 2014 at 23:43 | comment | added | HopDavid | Many Mars architectures call for refueling at Mars. And some call for one way trips. So, no, that's not the default assumption here. If I say I have enough gas to get to work, the default assumption is that I have enough to get to work, not get to work and come back. | |
| Nov 21, 2014 at 18:07 | comment | added | Russell Borogove | If I say "I'm going to the store" or "I'm going to work" or "I'm going to New York", the default assumption is that I'm coming back. | |
| Nov 21, 2014 at 17:47 | comment | added | HopDavid | @RussellBorogove If "going to Mars" were the same as "going to Mars and coming back", you'd have a point. But KeithS' last paragraph isn't describing a round trip. He seems to be saying LEO to Mars is 9 km/s -- which is wrong. | |
| Nov 21, 2014 at 17:29 | comment | added | Russell Borogove | @HopDavid - the crew may want to return to Earth at some point. | |
| Jul 24, 2014 at 12:16 | comment | added | LocalFluff | If astronauts spend half their time (sleeping and a few more hours per "day") in a 1 meter diameter hole inside a 3 meter diameter cylinder with the length 2 meters filled with one meter water or fuel or waste around, that would weigh about 13 tons (not thousands of tons). And that alone would cut the radiation exposure in half. | |
| Jun 17, 2014 at 0:05 | comment | added | KeithS | Very probably. For an Earth-Mars transition using a Hohman orbit (which would result in the spacecraft staying between the orbits of the two planets rather than slingshotting around a closer orbit to the Sun), the numbers we already have for lunar excursions represent the highest long-term dose as they represent the dose at the closest point of the excursion to the Sun (outside Earth's protective magnetic field). As you get closer to the Sun, you are exposed to a greater arc of its radiation, and thus a greater amount of power that you must moderate with additional shielding. | |
| May 17, 2014 at 15:48 | comment | added | MercuryPlus | Don't radiation thickness requirements (for water shields) change according to distance from the Sun.? I'm assuming a spacecraft at Mercury would need thicker shielding than one at Mars. . . | |
| May 17, 2014 at 14:30 | comment | added | HopDavid | "going to Mars using a Hohmann transfer orbit takes about as much delta-V as getting to LEO in the first place" -- Getting to LEO takes about 9 km/s. From LEO trans mars insertion takes about 3.6 km/s. On arrival at Mars, a 1 km/s burn suffices to park the spacecraft in an elliptical orbit whose periapsis passes through Mars' upper atmosphere. The delta V is about half that of getting to orbit. | |
| May 15, 2014 at 15:41 | history | edited | KeithS | CC BY-SA 3.0 |
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| May 15, 2014 at 15:33 | history | edited | KeithS | CC BY-SA 3.0 |
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| Sep 9, 2013 at 14:26 | history | edited | KeithS | CC BY-SA 3.0 |
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| Sep 7, 2013 at 0:38 | comment | added | KeithS | Probably not; the data I have is most concerned with gamma rays and neutron radiation, the two forms most commonly seen from nuclear waste (and the two hardest to shield against). Ionizing cosmic radiation is mostly gamma rays and protons, which are overall very similar to the radiation from nuclear waste. Protons are slightly lighter and so would have less energy at a given velocity (more easily stopped); but, because they're protons, if captured by the water they'd basically become H+ ions which could acidify the shielding water in time (not seen as much with nuclear waste). | |
| Sep 7, 2013 at 0:28 | comment | added | James Jenkins | There are several types of harmful radiation in space, does the 7 centimeter halving apply to all of them? | |
| Sep 6, 2013 at 23:06 | history | edited | KeithS | CC BY-SA 3.0 |
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| Sep 6, 2013 at 22:12 | history | edited | KeithS | CC BY-SA 3.0 |
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| Sep 6, 2013 at 20:58 | history | answered | KeithS | CC BY-SA 3.0 |