Meteorites - Revision history

Michel Lamontagne: moved the discussion to the discussion page

2023-01-25T16:11:46Z

moved the discussion to the discussion page

RichardWSmith: Discussion of the danger of dust (and smaller) sized meteors.

2023-01-24T11:02:33Z

Discussion of the danger of dust (and smaller) sized meteors.

RichardWSmith: /* Risk and Mitigation */

2022-10-04T23:23:08Z

Risk and Mitigation

RichardWSmith: Added settlements in lava tubes and a link.

2022-10-04T23:22:12Z

Added settlements in lava tubes and a link.

Michel Lamontagne at 18:41, 30 September 2022

2022-09-30T18:41:58Z

Michel Lamontagne: /* Risk and Mitigation */

2022-09-30T18:41:18Z

Risk and Mitigation

Michel Lamontagne: /* Risk and Mitigation */

2022-09-30T18:37:43Z

Risk and Mitigation

Michel Lamontagne: /* Observations of Meteorite Impacts on Mars */

2020-11-10T21:32:59Z

Observations of Meteorite Impacts on Mars

Michel Lamontagne at 19:50, 13 September 2020

2020-09-13T19:50:51Z

Michel Lamontagne: /* Risk and Mitigation */

2020-09-13T19:50:07Z

Risk and Mitigation

← Older revision		Revision as of 16:11, 25 January 2023
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	*From the table we can see that a large 1 km2 settlement might expect to receive between 4 and 96 impacts of 3,2 joules per year. Each of these might require some kind of repair, however, an underground settlement would be impervious to such small impacts. As the rate of impact decreases roughly by 100 for every mass interval of 10, impacts with the energy of a bullet, with 100 times more energy (400J vs 3.2), should be about 10 000 times less frequent. So the same 1 km2 settlement should be hit by a meteorite with the energy of a bullet every 100 years or more.		*From the table we can see that a large 1 km2 settlement might expect to receive between 4 and 96 impacts of 3,2 joules per year. Each of these might require some kind of repair, however, an underground settlement would be impervious to such small impacts. As the rate of impact decreases roughly by 100 for every mass interval of 10, impacts with the energy of a bullet, with 100 times more energy (400J vs 3.2), should be about 10 000 times less frequent. So the same 1 km2 settlement should be hit by a meteorite with the energy of a bullet every 100 years or more.
−
−	Discussion: The meteorites in this table are tiny, and even Mars' thin atmosphere would stop them. It is suggested that the table be expanded to include larger bodies. How large must a meteor be before it has a good chance of not breaking up / evaporating by Mars' atmosphere?

	==Observations of Meteorite Impacts on Mars==		==Observations of Meteorite Impacts on Mars==

@@ Line 13: / Line 13: @@
 The frequency of meteorites and their dimension are known<ref>BLAND, Philip A. Quantification of meteorite infall rates from accumulations in deserts, and meteorite accumulations on Mars. In : ''Accretion of extraterrestrial matter throughout Earth’s history''. Springer, Boston, MA, 2001. p. 267-303.</ref><ref>DYCUS, Robert D. The meteorite flux at the surface of Mars. ''Publications of the Astronomical Society of the Pacific'', 1969, p. 399-414.</ref><ref name=":0">An assessment of the Meteoritic contribution to the martian soil, George J. Flynn, journal of geophysics research, 1990</ref>.
-The chance of a direct hit is very low, but debris may damage the colony and will effect a much larger area.  Settlements in [[Lava tube|Lava Tubes]] will be largely immune from meteor impacts, except for large ones which are so close to cause cave ins.  (Since many of these lava tubes have lasted tens or hundreds of millions of years, short lived humans will justifiably ignore such dangers.
+The chance of a direct hit is very low, but debris may damage the colony and will effect a much larger area.  Settlements in [[Lava tube|Lava Tubes]] will be largely immune from meteor impacts, except for large ones which are so close to cause cave ins.  (Since many of these lava tubes have lasted tens or hundreds of millions of years, short lived humans will justifiably ignore such dangers.)
 In practice, settlements are likely to ignore the risk of large impacts as too rare to worry about.
@@ Line 19: / Line 19: @@
 {| class="wikitable"
 |+
-Meteorite impact frequency on Mars<ref name=":0" />
+Dust (or smaller) Meteorite impact frequency on Mars<ref name=":0" />
 ! colspan="2" |Diameter interval
 !diameter, average
@@ Line 119: / Line 119: @@
 *From the table we can see that a large 1 km2 settlement might expect to receive between 4 and 96 impacts of 3,2 joules per year.  Each of these might require some kind of repair, however, an underground settlement would be impervious to such small impacts.  As the rate of impact decreases roughly by 100 for every mass interval of 10, impacts with the energy of a bullet, with 100 times more energy (400J vs 3.2), should be about 10 000 times less frequent.  So the same 1 km2 settlement should be hit by a meteorite with the energy of a bullet every 100 years or more.
 ==Observations of Meteorite Impacts on Mars==

@@ Line 13: / Line 13: @@
 The frequency of meteorites and their dimension are known<ref>BLAND, Philip A. Quantification of meteorite infall rates from accumulations in deserts, and meteorite accumulations on Mars. In : ''Accretion of extraterrestrial matter throughout Earth’s history''. Springer, Boston, MA, 2001. p. 267-303.</ref><ref>DYCUS, Robert D. The meteorite flux at the surface of Mars. ''Publications of the Astronomical Society of the Pacific'', 1969, p. 399-414.</ref><ref name=":0">An assessment of the Meteoritic contribution to the martian soil, George J. Flynn, journal of geophysics research, 1990</ref>.
-The chance of a direct hit is very low, but debris may damage the colony and will effect a much larger area.  Settlements in [[Lava Tubes]] will be largely immune from meteor impacts, except for large ones which are so close to cause cave ins.  (Since many of these lava tubes have lasted tens or hundreds of millions of years, short lived humans will justifiably ignore such dangers.
+The chance of a direct hit is very low, but debris may damage the colony and will effect a much larger area.  Settlements in [[Lava tube|Lava Tubes]] will be largely immune from meteor impacts, except for large ones which are so close to cause cave ins.  (Since many of these lava tubes have lasted tens or hundreds of millions of years, short lived humans will justifiably ignore such dangers.
 In practice, settlements are likely to ignore the risk of large impacts as too rare to worry about.

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 The frequency of meteorites and their dimension are known<ref>BLAND, Philip A. Quantification of meteorite infall rates from accumulations in deserts, and meteorite accumulations on Mars. In : ''Accretion of extraterrestrial matter throughout Earth’s history''. Springer, Boston, MA, 2001. p. 267-303.</ref><ref>DYCUS, Robert D. The meteorite flux at the surface of Mars. ''Publications of the Astronomical Society of the Pacific'', 1969, p. 399-414.</ref><ref name=":0">An assessment of the Meteoritic contribution to the martian soil, George J. Flynn, journal of geophysics research, 1990</ref>.
 {| class="wikitable"
 |+

@@ Line 109: / Line 109: @@
+|
 |}
-Average impact velocity : 300 m/s
+*Average impact velocity : 300 m/s
-Average density: 1800 kg/m3
+*From the table we can see that a large 1 km2 settlement might expect to receive between 4 and 96 impacts of 3,2 joules per year.  Each of these might require some kind of repair, however, an underground settlement would be impervious to such small impacts.  As the rate of impact decreases roughly by 100 for every mass interval of 10, impacts with the energy of a bullet, with 100 times more energy (400J vs 3.2), should be about 10 000 times less frequent.  So the same 1 km2 settlement should be hit by a meteorite with the energy of a bullet every 100 years or more.
 ==Observations of Meteorite Impacts on Mars==

@@ Line 5: / Line 5: @@
 ==Risk and Mitigation==
-Small meteorites are best handled by a thick layer or [[regolith]]. [[Mars One]] planed to cover their inflatable [[greenhouse]]s with at least 2 meters of it. Most meteorites are small. [[self-healing puncture protection]] for [[space suit]]s and [[house|facilitie]]s should be installed.
+*Small meteorites are best handled by a thick layer or [[regolith]]. [[Mars One]] planed to cover their inflatable [[greenhouse]]s with at least 2 meters of it. Most meteorites are small. [[self-healing puncture protection]] for [[space suit]]s and [[house|facilitie]]s should be installed.
-Bigger meteoroids are not frequent, but they can happen. Meteorites a few centimeters in diameter would be fatal. Little can be done to fend them off, the kinetic [[energy]] is much too high.
+*Larger meteoroids are rare, but they can happen. Meteorites a few centimeters in diameter would be fatal. Little can be done to fend them off, the kinetic [[energy]] is much too high.
+*There are possible precautions. One is to modularize the settlement with [[fail-safe|redundant]] facilities.  In the case of an impact, the affected module may be damaged, but the remaining modules allow the surviving settlers to continue the settlement process.
-There are possible precautions. One is to modularize the settlement with [[fail-safe|redundant]] facilities.  In the case of an impact, the affected module may be damaged, but the remaining modules allow the surviving settlers to continue the settlement process.
+*For even bigger impacts, the required distances between the redundant modules may be larger. Independent settlements should be equipped to work autonomously, but cables and pipes between them can help them support each other in emergency situations, e.g. to supply [[oxygen]] and [[electricity]]. A [[railroad]], airlock or tunnels between them , depending on distance, would allow material and personnel transportation. However this type of redundancy may be more appropriate for internal accidents, such as fires or structural failure, than any eventual asteroid impact.
 The frequency of meteorites and their dimension are known<ref>BLAND, Philip A. Quantification of meteorite infall rates from accumulations in deserts, and meteorite accumulations on Mars. In : ''Accretion of extraterrestrial matter throughout Earth’s history''. Springer, Boston, MA, 2001. p. 267-303.</ref><ref>DYCUS, Robert D. The meteorite flux at the surface of Mars. ''Publications of the Astronomical Society of the Pacific'', 1969, p. 399-414.</ref><ref name=":0">An assessment of the Meteoritic contribution to the martian soil, George J. Flynn, journal of geophysics research, 1990</ref>.

← Older revision		Revision as of 21:32, 10 November 2020
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	[[Mars Odyssey]]'s THEMIS instrument and [[Mars Express]]' High Resolution Camera (HRSC) were able to provide supplementary observations of the area to constrain the impact date to some time between November 12, 2004 and January 6, 2006. Since this first discovery in January 6, 2006, another 20 new impact craters have been discovered by the MOC.		[[Mars Odyssey]]'s THEMIS instrument and [[Mars Express]]' High Resolution Camera (HRSC) were able to provide supplementary observations of the area to constrain the impact date to some time between November 12, 2004 and January 6, 2006. Since this first discovery in January 6, 2006, another 20 new impact craters have been discovered by the MOC.
		+
		+	== Martian meteorites on Earth ==
		+	A significant source of knowledge about Mars are the [[Martian Meteorite List\|Martian meteorites]] that were found on Earth.

	==See also==		==See also==

@@ Line 117: / Line 117: @@
 For reference, the impact of a pistol bullet is about 400 Joules and the impact from a rifle shot 2700 joules.
-From the table we can see that a large 1 km2 settlement might expect to receive between 4 and 96 impacts of 3,2 joules per year.  Each of these might require some kind of repair, however, an underground settlement would be impervious to such small impacts.  As the rate of impact decreases roughly by 100 for every mass interval of 10, impacts with the energy of a bullet, with 100 times more energy (400J vs 3.2), should be about 10 000 times less frequent.  So the same 1 km2 settlement should be hit by meteorites with the energy of a bullet every 100 years or more.
+From the table we can see that a large 1 km2 settlement might expect to receive between 4 and 96 impacts of 3,2 joules per year.  Each of these might require some kind of repair, however, an underground settlement would be impervious to such small impacts.  As the rate of impact decreases roughly by 100 for every mass interval of 10, impacts with the energy of a bullet, with 100 times more energy (400J vs 3.2), should be about 10 000 times less frequent.  So the same 1 km2 settlement should be hit by a meteorite with the energy of a bullet every 100 years or more.
 ==Observations of Meteorite Impacts on Mars==