South Atlantic Anomaly affecting Fermi/GLAST

The South Atlantic Anomaly, a congenital dip of the life-protecting geomagnetic field affecting low-earth orbiting space craft, including the International Space Station.

A new study shows mission time for GLAST, the "Gamma Ray Large Area Space Telescope" renamed after Enrico Fermi in August is been strongly affected by its regular passes in orbit through the South Atlantic Anomaly (SAA).

Fermi delivered a spectacular and unprecedented in its detail First Light of the Gamma Ray sky in August, and is designed to detect tale-tale streams of highly energetic particles that precede a Gamma Ray Burst.

GRB's are Titanic explosions from the Dark Ages of cosmic history that flash intensely and then rapidly fade from view, nearly as old as the Universe. Fermi is designed to interrupt its mission to turn and rapidly study these still-mysterious phenomena in response to the sudden flash of highly energetic Gamma Rays known to herald an arrival of a visible counterpart since early in the Space Age.

Fermi's general mission is to study the Gamma Ray sky, most, but not all, of which appears to originate from within the edge-on disk of our own galaxy.

GRB's have been detected in every area of the sky, however, without any optical counterpart until spaceborne telescopes began to gradually increase their manuverability and sensitivity in recent years. Opinions differ whether GRB's result when super-massive proto-stars in the early universe collapsed or if they result from binary neutron stars or blackholes falling onto one another.

The energy released is of great interest because, given their great distances, it is estimated each GRB release nearly as much energy as is known to exist in the entire present visible universe, all in a very brief moment, relatively speaking.

Fermi's mission is being perturbed by another long-observed phenomena, the anomalous dip on Earth's Magnetic Field lines over the South Atlantic.

This dip in Earth's magnetic field consistently brings highly charged particles trapped within the Van Allen Belts closer to Earth enough to affect spacecraft in low Earth orbit, including the International Space Station.
Twice each day, the ISS, in it's orbit inclined relative to the equator by 51 degrees, the station passes through this unusually low "hot zone."

The particles trapped along these field lines are also triggering GRB sensors on the watch for Gamma Ray Bursters, giving mission planners headaches and robbing scientists of valuable viewing time.

C. R. A. Augusto, C. E. Navia, and K. H. Tsui of the Instituto de Física in Brazil detail the phenomena in a paper published in Physics Review, Oct. 7.

Cosmic Rays Spark a Renewed Interest in the distant Voyagers

Their data are spread upon an impossibly thin wavefront measured in trillionths of a watt and hardly detectable over the background cosmic fizz. But both Voyagers I & II nevertheless regularly and obediently acknowledge a receipt of commands in a two way communication taking more than a full day to complete, even at the speed of light and after 30 years of hurling away from Earth.

From their remote "outposts," now just barely beyond the electromagnetic dominance of the Sun, these two prides of Pasadena and Dr. Sagan dutifully download basic but increasingly important information about the larger interstellar space we still share.

The Voyager's minimally-funded space weather station reports had been thought to be little more than a novelty after their primary missions were completed and their cameras were powered down. But their renowned robotic patience may finally be drawing some fresh attention sparked by a renewed interest among those intrepid hominids who want to journey beyond Earth's Moon but are confronted with the harsh realities of hard and heavy interstellar radiation.

"Global warming" would probably be welcome relief from the cold of the Kuiper Belt. Back on Earth, however, scholarly studies of a possible role for the secondary particles of Cosmic Rays impacting Earth's atmosphere and possibly playing a role in cloud formation on Earth, affecting albedo and even climate, refuse to go away. Cosmic Rays bombardment had been thought to be constant, except where deflected by our nominally variable star's sunspot cycle.

Both Voyagers are healthy, out there beyond the Termination Shock of the Heliopause, where the interplanetary medium buffets the interstellar depths, and both vehicles continue to send home points of data allowing us an, as yet, under-appreciated, sustained glimpse of Deep Space.

Cosmic Ray have a swinging variability after all, beyond that part of its stream that is moderated by nearby Solar influence, particularly during solar flares and CMEs here in the inner solar system.

Perhaps those who make it their business to follow space weather should add these faithful reports from Voyager to their posts of things like sunspot counts and the speed of solar protons per cubic meter, etc.

Even during the present protracted solar minima, though, the incidence of nucleons out there where the Voyagers travel, heavy ions with punches greater than 50 million electron Volts seems to be at a slump, over the past few months, for example. Even in the long distant night, the Voyagers repeat the oldest message in their lesson books: For every answered question, two more to take its place. The Universe is more than we know.

Does this slight variation in the bombardment of "Galactic Cosmic Rays," or GCR's bring into disrepute beliefs most experts hold that the Cosmic Ray background is steady?

On Earth, the launch last month of GLAST, tuning up now to begin looking for deeper anisotropy to their infall, Cosmic Rays should be "peaking" at an unusually long Solar Minimum. GLAST is just getting started when the "seeing" should be good.

It could only be better out there beyond 100 A.U.'s "Billions and Billions" of kilometers out from under the garish sun.