May 21, 2018

09.06.10: H2O in the Solar Neighborhood.

Water, water, everywhere… over the past year or so, evidence for water in the solar system has been mounting in some unlikely places. The poles of our Moon. Ice geysers on Enceladus. Now add the denizens of our asteroid belt to the list; earlier this year, scientists at the Johns Hopkins University of Applied Physics in Laurel, Maryland have revealed findings that water ice may pervade the surface of asteroid 24 Themis. This comes from six years of careful study carried out by astronomers Andrew Rivkin and Joshua Emery using NASA’s Infrared Telescope Facility. By studying the asteroid of seven separate occasions, a definite signature pattern of water ice and carbonaceous organic materials has emerged. Much like the revelation of water hydroxyls on the Moon, this comes as something of a shocker; the asteroids bordering the inner solar were long suspected as being bone dry. 24 Themis orbits the Sun at a distance of 297 million miles, or about 3 A.U. “This is exciting because it provides us a better understanding about our past and our future,” stated Don Yeomans of NASA’s Near-Earth Object Program office at JPL. Clearly, the possibility of a “wet asteroid belt” may have further implications not only for space travel, but as to the origins of terrestrial water as well. Keep in mind, the ratios mentioned are often minuscule in an everyday sense; for example, the amount of water reckoned on the lunar surface during last years’ media blitz was on the order of one liter per ton of lunar regolith. Clearly, it will be a major technical feat to harvest such a small amount in useful quantities. Obviously, many sources of extraterrestrial water are still bone dry by the standards of the harshest terrestrial desert. Still, this tantalizing find may provide clues to fuel speculation as Dawn mission enroute to the asteroids Vesta and Ceres draws near; Vesta displays a curious reddish brown spectrum highly suggestive of a tarry surface, and Ceres has been proposed to perhaps harbor a subterranean ocean similar to what’s thought to exist beneath the surface of Jupiter’s large moon, Europa. This all begs for further exploration and could drive a new emphasis towards the President’s eluded to “Mission to an Asteroid” by 2030 or so… Apophis in 2029, anyone?

22.03.10- On the Trail of Lunar Water.

Last year’s big news story was the announcement of water on the Moon. This evidence came from five separate sources, and spanned over a decades’ worth of data. This climaxed with the October 9th impact of the LCROSS spacecraft in the quest for a moisture laden plume. Now, a reanalysis of lunar samples returned by Apollo astronauts have turned up evidence of microscopic water beads imbedded in volcanic glass. This leads scientist Alberto Saal to suggest that the lunar interior may contain water in the order of 745 parts per million, a tiny but measureable amount.

The first whiff of water in the form of clay hydroxyls came from the Clementine and Lunar Prospector orbiters in the mid 90’s. Cassini imaged the Moon in the infrared on its way out to Saturn, but the water signature detected at the time was suspected to be due to spacecraft contamination. More recently, lunar water got a boost from NASA’s spectrometer aboard the Indian orbiter Chandrayaan 1 and observations by the Deep Impact spacecraft in its role of simulated exoplanet hunter… keep in mind, the amount of water being discussed is tiny; were talking maybe a liter per ton of lunar regolith near the poles, and half that amount at the equator! With the cancellation of Constellation, it’s to be seen if any of the proposed unmanned rovers will take up the hunt for lunar water over the next few years.

LRO/LCROSS: Back to the Moon.

A quiet storm began last month at Cape Canaveral Air Force Station. On June 18th, 2009, the Lunar Reconnaissance Orbiter (LRO) lifted off towards our nearest neighbor, the Moon. This marks the first of NASA’s unmanned missions that will herald the eventual return of man to the Moon. As this month also marks the 40th anniversary of the historic Apollo 11 landing, this return couldn’t be more timely. [Read more...]