n Hal Clement's classic novel Mission of Gravity, humans are investigating Mesklin, a giant planet with a mass so great and rotation so rapid that the gravity varies from 3 gs at the equator to 700 gs at the poles. It's also cold enough to have a methane ocean. Unfortunately, the human investigators have lost a rocket with expensive instrumentation in the polar region, and they'd like it back. While humans can survive at the equator in spacesuits, there's no way they could survive an expedition to the polar regions. Fortunately, they have discovered intelligent life on the planet, a species resembling a 15-inch caterpillar with pincers that they can communicate with. Best of all, the group of alien sailors Charles Lackland comes across are natives of the polar regions, and, in fact, feel out of place in the equatorial region.
Lackland makes a deal with Barlennan, the Mesklinite captain, who quickly learns English. In exchange for providing information such as maps and weather reports, the Mesklinite crew will try to retrieve the equipment. However, there's a problem. There's no connection between the ocean where they currently are and the one they need to get to in order to get closest to the rocket. Maps assembled from photographs taken by orbiting rockets reveal, however, that only three hundred miles away, they can reach a large navigable river that empties into the desired ocean.
The problem now is how to get the 40-foot long Mesklinite ship--which resembles an array of rafts tied together--overland. Eventually, they decide to construct a metal sled to tow behind a tank Lackland uses for transportation. The ship is disassembled, and reassembled on the sled. But as they ready to embark on the journey, Lackland is unaware that Barlennan has his own secret motives for wanting to find the rocket.
Outstanding details, simple plot
Hal Clement was recently named the 1998 Grand Master by the Science Fiction and Fantasy Writers of America, and Mission of Gravity is his best known novel. Often regarded as one of the pioneering works of hard science fiction, it largely fulfills its reputation. Clement is at his best when he's describing the physical details of a high gravity environment. One of the especially poignant touches is the Mesklinites' paralyzing acrophobia, even when they're in the equatorial region. In their normal environment, much closer to the pole, a fall of a few inches would be fatal to Barlennan and his crew, and Clement makes effective use of this. He also deftly avoids a characteristic that plagues many works of hard science fiction: overexplaining. The science in Mission is revealed naturally through plot developments, and where explanations from the humans to Barlennan are necessary, they are usually simple and concise.
The story itself is enjoyable, but far from compelling. While the humans desperately want to recover their lost equipment, they often seem more worried about the cost than the data, which makes the stakes seem pretty low. The plot itself is barely complex enough to sustain this short novel, while Mesklin as a world is so vast and interesting that it demands a much more thorough exploration. Within the space constraints of a 1953 magazine serial, Clement is able to create an acceptable balance between these two competing elements, but both leave a little dissatisfaction. The Mesklinites themselves, though physically very different, psychologically seem too much like humans, resulting in a few chapters that aren't particularly distinguishable from stories set in 19th-century African jungles or the South Seas.
On the whole, however, Mission of Gravity deserves its reputation as a classic. Clement sets a fine example for integrating scientific facts into a fictional narrative, and while the storytelling isn't quite as inventive, it's still a fun book to read.
