explorer s-46 Archives - Galactic Journey

So far this month, it's Air Force: 1, Army: 0. The latest Explorer probe, launched today atop an Army contractor-made Juno II booster failed to orbit. This is in contrast to Pioneer 5, launched March 11 on an Air Force contractor-built Thor Able, which is still beeping merrily away to the orbit of Venus. Both launches were made under the auspices of the National Aeronautics and Space Administration (NASA).

The failed probe was the 10.2 kilogram "S-46," and it was another University of Iowa special designed to further investigate those belts of charged particles girdling the Earth. They're called "Van Allen" belts after the professor whose team first discovered them back in 1958, and which has produced many of NASA's satellite experiments to date.

S-46 was sent toward the heavens by the Juno II, a modified version of the Jupiter missile now being based in Turkey and Italy. At the Jupiter's top is the same cluster of Sergeant rockets that, mated with the smaller Redstone rocket, launched America's first space probe in January 1958. S-46 was supposed to go into a high, eccentric orbit, similar to that of Explorer 6, to give all of the belts a thorough mapping.

To those wondering why anyone would bother to pull the same stunt twice, the answer is that the environment around the Earth is always changing. There are terrestrial and solar factors, all of which increase and decrease the magnetic and particlular characteristics of orbital space. The more data we can collect, the more continuously we can collect it, and the more vantages from which it can be collected, the more complete can by our understanding of geophysics.

Sadly, while the Jupiter first stage performed fine, it looks like one of the Sergeants misfired, which caused the whole second stage to go cock-eyed. The ill-fated would be Explorer never made to orbit.

I feel badly for the folks at UoI, many of whom have become personal friends. This Juno II was the last back-up left over from the Army's lunar Pioneer program (that launched Pioneers 3 and 4). It looks unlikely that NASA will have another spare booster handy to launch another copy of S-46 for some time, if ever.

This doesn't mean we'll never have another Van Allen mapper in orbit. It just means the fellow after whom they were named may not have first dibs on their next investigation.