Some pretty "heavy" ideas here! (****)

In "Mission of Gravity", Hal Clement created Mesklin, a very odd planet indeed - so massive, so oblate and spinning so rapidly that its gravity varies from 3g at its equator to 700g at its poles! Its day is little more than 20 of our minutes long and its temperature is so low that it has liquid methane oceans. Its high eccentricity orbit causes seasons of grotesquely uneven length. Charles Lackland and his team of human space faring scientists can manage at the equator with mechanically assisted survival suits but existence under 700g at the poles is simply beyond human engineering capabilities. Recovery of a rocket with all of its instrumentation landed at one of the poles is a problem that seems insurmountable until our intrepid explorers stumble into a serendipitous encounter with Barlennan, a rather audacious native traveling merchant. Barlennan's species, best described as 15 inch caterpillars with outrageously strong pincers, has evolved under the extreme conditions at Mesklin's pole. Being on an exploratory mission themselves in Mesklin's equatorial region, they admit to feeling somewhat giddy and "light"-headed under what they describe as virtually non-existent gravity in comparison to what they are used to on their home turf!

Clement has created a delightfully simple plot that revolves around the hard science of his hypothetical planet. Lackland enlists Barlennan's aid in recovering the stranded hardware in exchange for information such as maps and weather forecasts. Along the route to the pole, Clement proposes physical problems and raises questions - What might the weather of such a planet be? How does a reconnaissance satellite achieve a low altitude geosynchronous orbit of a planet that is spinning at such an enormous speed? How might its natives appear having evolved under such dramatically different conditions? How might their psychological outlook on this world be different as a result of those physical conditions? How might engineering problems, simple on earth, be made astonishingly difficult on Mesklin and what modified approaches would be used in their solution? What surprising effects are caused by the universality of physical rules that apply regardless of the local gravity?

It should come as no surprise to a reader to learn that Clement was also a skilled high school science teacher. The development of the science in his story is lean, lucid and clear to a fault. Clement lets the plot and his characters naturally encounter the problems, puzzle through their difficulties and propose and create clear logical solutions which seem to clarify the science. Clement never bores the reader with dull narrative explanations, never over-explains and shows rather than tells.

Sadly, at less than 200 pages, "Mission of Gravity" suffers by its very brevity. Mesklin is such a vast, unique and dramatic concept that Clement barely scratched its surface. I found myself wanting much, much more science and a greater depth in the development of potential avenues to explore. The soft science was effectively ignored. For example, Barlennan's attitudes and reactions were anthropomorphized to the extent of being cartoonish (C'mon, Hal ... let your aliens be alien!). Barlennan's mastery of English came conveniently easily but communication with other races on the planet was abandoned as an unsolved problem.

"Mission of Gravity", while not a frenetic page-turner, is an enjoyable story that ends on a mild plot twist and a universally warm, optimistic note. It has earned the moniker "classic" and I certainly look forward to the sequel "Starlight". Perhaps the broadened scientific horizons that I hope for will appear there!

Paul Weiss