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The Planetary Report

On the Cover: The plucky Mars Global Surveyor's Mars Orbiter Camera (MOC) zoomed in to get a closer look at erosion processes exposing hundreds of layers of similar thickness, texture, and pattern in an impact crater 64 kilometers (40 miles) wide in western Arabia Terra. In this MOC image, dark, windblown sand enhances the appearance of the layers. These layers provide a record of repeated, episodic changes that took place sometime in the Martian past. Layers toward the center of the crater are nearly horizontal, but those closer to or draping over the crater walls are tilted toward the basin center. Such relationships suggest the sediments creating these layers were deposited from above -- perhaps settling out of the Martian atmosphere or else out of water that might have occupied the crater as a lake.
NASA / JPL / MSSS

Volume 21, number 1
January/February 2001

Evolving Visions

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(Planetary Society members only)

Features

Opinion: Systems Engineering -- A Personal Memoir
One of the unsung spin-offs of the space program may be the rise of the field known as systems engineering. Without this sort of skill, which enabled all parts of a Saturn V (each stage built by a different contractor) to work flawlessly together to rocket humanity to the Moon, the accomplishments of the past four decades would have been impossible. The recent losses of several spacecraft refocused attention on systems engineering, and a long-time practitioner of the art (and Technical Editor of The Planetary Report), Jim Burke, ruminates on lessons still to be learned.

Odd Asteroids and Closet Comets: The Distinction Blurs
Don Yeomans is an old friend of The Planetary Society, having written many articles for our magazine over the years. He is also a distinguished scientist, so when he published a piece in the prestigious science journal Nature about our changing views of comets and asteroids, we were after him immediately to adapt it for The Planetary Report. Here you'll read how our definitions of small objects in our solar system may need substantial reworking.

The Express to Mars
NASA and the United States are not the only players in Earth's exploration of its neighboring world. The Japanese Nozomi mission is on its way to the Red Planet, and a consortium of European nations is planning an ambitious mission to Mars to launch in 2003: Mars Express. We asked Robert Burnham, eminent science writer and former editor of Astronomy magazine, to take a close look at the plans and report to Society members.

Hunting the Elusive "Wow"
In the Search for Extraterrestrial Intelligence (SETI), there is only one possible signal from another civilization that has entered the realm of legend: the "Wow" signal detected at the Ohio State Radio Observatory in 1977. As tantalizing as it was, this signal failed the most important test of authenticity -- it did not repeat. The Planetary Society recently supported an attempt to redetect "Wow," and here we offer members an account of the results. By Robert Gray.