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Although a substantial changes in the Earth's magnetic field (e.g., as associated with a geomagnetic reversal where the magnetic field strength may be reduced to 5% of the current strength) are rare events, the impact on space weather as felt by objects in Earth orbit would seem to be great enough that some consideration would have been given to this issue.

What, if any, planning has been or is being done to address this potential danger to satellite operations? What kind of measurements are performed - in space - for better understanding the situation and corresponding processes? Is there any kind of monitoring - in space - on the current state of Earth's magnetic field, its development and space weather phenomena, which may influence the field?

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  • $\begingroup$ I am not sure about the tagging; I stink at tagging. ('radiation' seems to be a superset of 'space weather', but a 'space weather' tag might be meaningful. 'magnetic-fields' would be useful for studying, handling dangers of, and exploiting solar/stellar and planetary magnetic fields.) $\endgroup$ – Paul A. Clayton Jul 16 '13 at 23:56
  • $\begingroup$ I'm not sure if this is really a space exploration question, unless you specifically mean the effects on spacecraft. See this meta post. $\endgroup$ – gerrit Jul 16 '13 at 23:58
  • $\begingroup$ @gerrit I was primarily thinking in terms of terrestrial satellites--thus the mention and tag of "space weather". Will edit to include this. $\endgroup$ – Paul A. Clayton Jul 17 '13 at 0:04
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    $\begingroup$ The question could belong into geosciences, physics, biology or basically just anywhere else. It boils down to the question of how our modern society can handle the side effects. While nature can (and did countless times before), electronics are an issue - so are satellites, in every conceivable way. $\endgroup$ – s-m-e Jul 17 '13 at 0:08
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    $\begingroup$ @PaulA.Clayton what if we re-word this to something like "How would a geomagnetic reversal effect Earth's satellites (natural or artificial)?" I'd vote to re-open for something like that. Interesting topic! $\endgroup$ – JohnB Jul 17 '13 at 3:00
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First of all, it is a bit odd to talk about specific plans. If you think about emergency procedures for other natural phenomena, such as Hurricanes or Earth quakes, you need to keep in mind that a reversal is a long-term process which is supposed to take decades to centuries. This is what is called geological time scales. In a way, some scientist say, that the "next" reversal has already started. For proving this statement, scientist usually refer to the current characteristics of Earth's magnetic field. It is somewhat different from a "clean" dipole, which it is supposed to be according to basic physics.

Since the process of Earth's magnetic field's reversal was first simulated by computers, it has been agreed on that the overall field strength (around 50µT at the Earth's surface) will not drop significantly. For further reading, have a look at the ground-breaking work of Gary A. Glatzmaier, Paul H. Roberts et al. A three-dimensional self-consistent computer simulation of a geomagnetic field reversal, Nature, 1995.

Talking about space exploration in this context, there are plenty of missions which relate to this issue. First, you need plenty of data / observations of Earth's magnetic field for understanding it (and for tuning & verifying the computer models). Second, you need monitoring of the field with respect to sudden changes. Sudden changes may only be caused by solar activity, so from a scientific perspective, such missions actually monitor the solar weather.

But talking about plans and although such sudden changes should not trigger a reversal on their own, those effects account for most problems here on Earth with respect to Earth's magnetic field. The most prominent example is the geomagnetic storm of March 1989, which had significant influence on the power grid in North America. Although there have been improvements to e.g. power grids, to the best of my knowledge, there is no overall plan of how to handle a massive solar storm (thus a massive change in Earth's magnetic field) in most countries. The space probes at the Earth-Sun-system's Lagrangian points remain the first (and last) line of defence (for early warning) against such events.

Notable missions for looking at Earth's magnetic field: Magsat, Ørsted, Swarm.

Notable missions monitoring solar activity: STEREO, International Sun/Earth Explorer 3 (ISEE-3), WIND, ACE, SOHO.

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I'm going to attempt to answer your later questions :

What kind of measurements are performed - in space - for better understanding the situation and corresponding processes? Is there any kind of monitoring - in space - on the current state of Earth's magnetic field, its development and space weather phenomena, which may influence the field?

Yes, there's monitoring.

Ernestopheles already mentioned two magnetospheric missions (Swarm hasn't launched yet). There's also ESA's Cluster-II mission, the JAXA/NASA Geotail, and NASA's TWINS. There's also the Van Allen Probes (formerly RBSP) to study the radiation belt, and magnetometers in the various GOES satellites. NASA's also working on MMS that might launch next year.

As for the type of measurements -- well, there's the magnetometer data, but there's also insitu measurements of the solar wind (flux, composition, velocity, etc.), and remote sensing (spectroscopy for the most part)

As for the planning for operations impact ... I don't know if any satellites are prepared for long-term bombardment by space weather. My understanding is that for more recent spacecraft, even geostationary and LEO ones have some measures that they can take in case of an Earth-directed coronal mass ejection (CME). As the CMEs have mass, they also have a charge and magnetic field associated with them, and so may cancel out the Earth's magnetic field. There are a number of ground-based magnetometer sites that record this information, as well as the daily fluctuations of the magnetic field in general. I believe that SuperMAG is an aggregator, and not a direct collection project, but they'd show where those sites are.

In some cases, to protect against CMES, operators tilt the panels so it's a smaller target ... the problem is, this also means they're getting less power, so not all spacecraft can do this long-term. If the panels are fixed to the spacecraft, you have to tilt the whole thing to do it, and this can lead to thermal issues.

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  • $\begingroup$ Joe - the question is not about the solar weather or magnitosphere, but about magnetic pole reversal. Please re-read. $\endgroup$ – Deer Hunter Aug 6 '13 at 10:06
  • $\begingroup$ @DeerHunter : Magnetic pole reversal has nothing to do with the magnetosphere? And read the second paragraph -- there are questions about preparedness & monitoring. If pole reversal results in a weakened magnetosphere, then the solar wind is going to be more significant to spacecraft that would otherwise be protected ... I would have asked the spacecraft operator who sits in the office next door ... but he works on SOHO, which is at L1, and well outside of the magnetosphere. $\endgroup$ – Joe Aug 6 '13 at 12:21
  • $\begingroup$ Tantalum consumption will definitely go up. $\endgroup$ – Deer Hunter Aug 6 '13 at 12:40
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    $\begingroup$ Besides SuperMAG, you should mention the World Data Centre for Geomagnetism in Edinburgh. They are collecting data from quite a few locations. $\endgroup$ – s-m-e Aug 17 '13 at 18:32
  • $\begingroup$ may cancel out the Earth's magnetic field - I have seen a fair number of simulations of Earth's magnetic field and CME events. But I have never seen it being 'cancelled out'. Do you have a source for this? $\endgroup$ – s-m-e Aug 17 '13 at 18:38

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