South Atlantic Anomaly: Evolution & Solar Effects

[wolram]

http://arxiv.org/PS_cache/arxiv/pdf/0902/0902.2873v1.pdf

Abstract
The evolution of the particle background at an altitude of 540km during the time
interval between 1996 and 2007 is studied using the particle monitor of the High
Energy X-ray Timing Experiment on board NASA's Rossi X-ray Timing Explorer.
A special emphasis of this study is the location and strength of the South Atlantic
Anomaly (SAA). The size and strength of the SAA are anti-correlated with the the
10.7 cm radio
ux of the Sun, which leads the SAA strength by 1 year re
ecting
variations in solar heating of the upper atmosphere. The location of the SAA is
also found to drift westwards with an average drift rate of about 0.3=yr following
the drift of the geomagnetic eld conguration. Superimposed to this drift rate are
irregularities, where the SAA suddenly moves eastwards and where furthermore the
speed of the drift changes. The most prominent of these irregularities is found in
the second quarter of 2003 and another event took place in 1999. We suggest that
these events are previously unrecognized manifestations of the geomagnetic jerks of
the Earth's magnetic eld.

 

[Astronuc]

The spacecraft -killing anomaly over the South Atlantic​

A strange dent in Earth’s magnetic field doses orbiting craft with high levels of radiation. It's caused everything from periodic glitches to total mission failure.
https://astronomy.com/news/2021/02/hidden-spaceflight-danger-the-south-atlantic-anomaly
Radiation from the SAA has undoubtedly affected spacecraft , sometimes leading to their doom. One notable example is the Japan Aerospace Exploration Agency’s (JAXA) X-ray Astronomy Satellite. Also called Hitomi, it was launched into LEO in February 2016 to study high-energy X-rays from extreme processes throughout the universe.

But JAXA lost all contact with the probe on March 26 of that same year. Shortly after, the U.S. Joint Space Operations Center publicly confirmed that it had seen Hitomi break up into at least five pieces. And the largest piece was tumbling, eventually dislodging even more fragments. Hitomi, which had cost upwards of $270 million, was a total loss.

Although the exact details of the problems leading up to the loss are still debated, it is known that Hitomi’s star tracker, which told the spacecraft how it was oriented in space, repeatedly experienced problems when the craft flew through the SAA. It’s possible that radiation-induced damage to this system ultimately caused the spacecraft to rotate itself to death, making itself spin too fast as it tried to correct for positional problems that didn’t actually exist.

Similarly, in 2007, the satellite-based phone and data communications company Globalstar experienced the loss of several of their first-generation satellites. Again, the loss is believed to be related to degradation of electronic components by radiation damage incurred while passing through the SAA.

It’s not just satellites that have had problems, either. Computers and instruments aboard Skylab, the International Space Station (ISS), the space shuttle, and even SpaceX’s Dragon craft have all experienced glitches or other issues when passing through the SAA.

 

[jim mcnamara]

Makes me wonder about the effects on personnel in the space station...

 

[anorlunda]

The implication is that near-Earth devices are less radiation hardened than successful interplanetary devices. I suppose that's reasonable, but I didn't expect that.

Perhaps the designers may re-evaluate if the optimum choice is to use less hardening for near-Earth applications.

Or maybe they are saying that radiation in the SAA is more severe than in planetary space. It's unclear. This quote is from the linked article.

The SAA is the region where the inner Van Allen Belt dips closest to Earth — a mere 120 miles (190 km) above the surface. At that altitude, spacecraft in low Earth orbit (LEO) may periodically pass through the SAA, exposing them (and, in the case of manned missions, their occupants) to large amounts of trapped high-energy particles — i.e., potentially damaging doses of radiation.

See also
https://en.wikipedia.org/wiki/South_Atlantic_Anomaly

It's still unclear. Neither article compares the SAA with interplanetary space.