Mission of Gravity

mission-of-gravityby Hal Clement
Pyramid Books, 1962
Originally published in Astounding Science Fiction, 1953
Price I paid: 75¢

The giant, disk-shaped world of Mesklin was an Earthman’s nightmare―so cold that the seas were liquid methane and the snow frozen ammonia, with crushing gravity up to 700 times that of Earth. No human being could explore Mesklin’s surface.

Yet―a desperately needed research rocket was down on Mesklin. Someone had to go after it. That someone was the strangest explorer ever to appear in science-fiction―the Mesklinite merchant seaman, Barlennan―fifteen inches long, thirty-six legs, weighing hundreds of pounds. And, as it turned out, the sharpest trader an Earthman ever met!


The last time I read Hal Clement, I was unimpressed. Cycle of Fire had some neat things going for it, mostly its worldbuilding, but the book itself was a long slog of undeveloped characters in search of nothing in particular. I didn’t like it.

I picked up another Hal Clement book because I was curious. I think I may have seen this book, Mission of Gravity, mentioned as a good one elsewhere, but I was skeptical after my experience with Cycle of Fire. I decided to give it a shot anyway. After all, it’s been a hot minute since I really dug into a hard sci-fi book with weird aliens, and it seemed like it was time to pick that up.

I’m very glad that I did.

This story had a lot in common with the other Clement that I read, namely distinctive extraterrestrials and a planet with a lot of interesting features, but it cranked that up to eleven and didn’t let go. As with Cycle of Fire the book was a travelogue-type narrative about exploring a strange new world and getting to know its things and peoples, but unlike that book this one actually had a plot attached. It’s not much of one, just a simple fetch-the-MacGuffin, but it was still a lot better than aimlessness. In addition to that, the characters, while not super-developed, were at least present. The human character wasn’t much to talk about, but the aliens had personality, and as we all know, personality goes a long way.

The planet in question is called Mesklin. It’s almost a discworld. Unlike a capital-d version of a discworld, though, this one is held together by science and not magic. It’s big relative to Earth (although I never quite got a good read on how much bigger it is, which I think is a personal failing), and it spins very rapidly. As a result, it’s been flattened out substantially by the spin. The result of this is that the planet has variable gravity based on latitude. Near the equator, it’s a tolerable-but-still-high three gees or so, but near the poles, it’s a crushing 700 gees.

(Would that happen? I’ll take Hal Clement’s word on a lot of science, but I’m curious about this.)

This, along with the planet’s inhospitable atmosphere and frigid temperatures, would cause someone to assume that there’s no chance of life on this planet, intelligent or otherwise. Within the framework of this book, however, that’s not the case. The planet is populated by Mesklinites, intelligent creatures shaped something like caterpillars. They’re small relative to humans―the back of the book says they’re fifteen inches long so I pictured them as roughly the size of cats―and they have anatomies similar in many ways  to insects. They don’t have lungs, for instance, but something more akin to spiracles.

You’d also think that such creatures would mostly inhabit the equatorial regions, where the gravity is lower, but that’s also not the case. While they’re not necessarily comfortable all the way at the poles, they do tend to lie at the higher latitudes, around three or four hundred gees.

Our main Mesklinite is named Barlennan. He’s a trader and an explorer. His ship, the Bree, sails up and down the methane seas of Mesklin looking for things to buy and sell. He’s good at it, a shrewd negotiator and a brave little caterpillar thing. At the start of the book we’re introduced to him, his crew, and a human named Lackland, who is stationed near the equator, living uncomfortably at three times his normal body weight. Barlennan and Lackland have been working together to solve a problem. It seems that Lackland’s scientific team, which is in orbit of the planet, has lost a probe. It landed near the south pole, where humans can’t possibly go, so Lackland has contracted Barlennan and his crew to go get it for him.

What follows is a pretty interesting little trek where the human and the Mesklinites get to know one another better. We learn that Mesklinites don’t like heights. This makes a lot of sense, considering that in their native gravity a fall of six inches can kill. They know nothing of the concepts of “throwing” or “jumping,” and being introduced to those concepts terrifies them, although not for long.

See, one of the best things about this book is that while the Mesklinites are primitive by human standards, they aren’t stupid. Barlennan is an excellent example of that. He begins to grasp the concepts that Lackland introduces him to very quickly. He knows that the humans are capable of things that the Mesklinites aren’t, but he doesn’t put it down to magic or sorcery or anything like that. He just reckons that there are scientific principles to which his people have not been introduced yet. This becomes more important in the end.

At one point the ocean ends and our heroes have to figure out a way to traverse the land in order to reach the south pole. This is accomplished by strapping the Bree to a tank thing that Lackland brought down and pulling it like a sled. There are some obstacles in the way―a sheer rock face at one point and a group of hostile Mesklinites at another―but these setbacks are all conquered by careful planning and resourcefulness.

One thing that can’t be offset by these qualities is the fact that gravity is increasing as the journey moves south. After a point, Lackland just can’t take it anymore, so he goes back up into orbit. From here on out, the story follows Barlennan and his crew exclusively. The point of view up to this point had been theirs for the most part anyway. We’re introduced to Lackland as a strange, alien creature who walks on two legs and is huge. Still, I thought this was an interesting development. Lackland is still present in the story, he just talks to our heroes via radio, a concept that the Mesklinites took to rather quickly.

Using human science and Mesklinite hardiness, the journey continues. There’s another group of Mesklinites that prove to be trouble, a group that is able to fly. They live in a region with a good deal less gravity than Barlennan and his crew hail from, so they don’t have the same instinctive fear of heights that our protags do. These Mesklinites, after some fruitful trading, are also a bit xenophobic, so they decide that the crew of the Bree are all spies and order them put to death. Yet again, human science wins the day when Lackland communicates certain principles to Barlennan that give them the upper hand. Among these is a crossbow, which the crew gained from a different set of Mesklinites earlier in the story. Barlennan and crew have very little knowledge of projectile weaponry. To them, throwing things is alien enough.

The story states that in their native latitude, the acceleration due to gravity is somewhere along the lines of two miles per second squared. I’m going to take Clement’s word on that since I’m not exactly sure how to do the math, but this is yet another example of how well-thought-out this whole species―its biology, customs, and abilities―is, and how those things exist in response to their environment. Considering that he was a real-life scientist, this is probably not much of a surprise.

One remarkable thing about this book is how little antagonism exists between Barlennan and Lackland. There are misunderstandings and differences of opinion, but they get along very well from the start. One might even fault the story for being a little too optimistic on that part, but I’m not gonna.

With the flying Mesklinites taken care of, our crew sets out for the south pole again. Once there, they find that the entire pole is on an unpassable ridge. The Mesklinites are unable to climb it now that they’re back in an area of high gravity, so they have to go around. Yet again, resourcefulness saves the day, and with a few tips from the human crew in orbit, Barlennan makes his way to the probe the humans need so badly. It’s a research probe, and the humans think that the data it contains will help them learn a lot about gravity, perhaps even ways to defeat it.

All of this comes to a head when Barlennan reaches the thing and comes up with a way of accessing it. It turns out that he’s ready to strike a bargain. All this time he’s been playing his real intelligence close to his chest (or whatever Mesklinites have), and in a surprising move, he says that he won’t retrieve the data for the humans until they make it worth his while. He’s had plenty of time to learn that the humans have science and technology that the Mesklinites don’t, and he wants in on it.

Lackland explains that so much of human science is beyond their abilities. Heck, a lot of it is beyond his abilities. He tells Barlennan that science is so advanced that it takes years and years for even human scientists to begin to learn to grasp it, needing to learn mathematics, physics, chemistry, and so on. There’s no way that the humans could bring the Mesklinites up to their level.

Barlennan acknowledges this and states that he’s not looking for rocket science or tanks or anything like that. What he wants is the groundwork. He wants the scientific method. Hearing this, the humans quickly agree.

It’s interesting that the resolution to this story revolves around something much the same as the other Clement book I’ve read. In the end, the solution is the scientific method. In Cycle of Fire, it’s stated that that knowledge will save Dar’s people from their regular extinctions and setbacks. In Mission of Gravity, it’s a desire to learn and create and engineer that causes the Mesklinites to want the idea. Either way, it’s clear that Hal Clement has a high opinion of the concept, which is great because I do too.

We don’t learn anything about the journey back or what the Mesklinites do with their newfound scientific method, nor do we learn if the probe’s data was at all worth it. That’s okay, it’s nice to think that everything worked out well afterward.

So this book was a joy to read. It had a lot more going for it than the previous Hal Clement book I’ve read, so that makes me happy. If I’m going to level some complaints, they’ll probably be pretty similar to the ones in Cycle of Fire, namely that the humans have very little personality, the dialogue isn’t great, and the hard science takes the forefront to such things as interpersonal conflict. But those are minor complaints in this case, whereas usually they’re the major flaws I find in a book. This book was still very well-written. While the humans didn’t have much personality, the Mesklinites did, and that means a lot to me. Perhaps one could complain that the Mesklinites were a little too human in a cognitive sense and were only really alien in their anatomies, I don’t think that would be fair. Sure, you could say that their responses to the environment were typical of how humans might react in those situations, but in the end, you have to stop and ask just how alien an author can make his aliens without being arbitrary for its own sake. If the only metric we currently have is how humans react to their environment, I don’t think there’s too much wrong with basing an alien society on a similar metric, especially when the results make a lot of sense.

There’s also a bit where a human scientist is using a slide rule. This amuses me deeply.

I like this book. I see it touted as a classic sometimes, and I think it deserves that status.

I’ve just learned that the Mesklinites, along with Dar’s people from Cycle of Fire, were featured in Barlowe’s Guide to Extraterrestrials, which I just find neat. It’s been at least twenty years since I’ve set eyes on that book, and now I’m starting to think I need to find another copy. I wonder how much more I’ll get out of it now than I did then.


5 thoughts on “Mission of Gravity

  1. Since you liked this one, you’ll probably like the sequal too; they’re really similar.

    I have them in an edition that has both books and an essay discussing the science bound together in one volume, which is fun.


  2. Whadaya’mean amused by a slide rule? I learned to use one in high school, just before Texas Instruments conquered the planet. Here’s something else that will amuse you — it sounds like a scientist joke, but it’s true. How do you adjust a slide rule that is out of allignment? Hold it diagonally and rap it sharply on the floor. Really. Syd Logsdon


  3. Yes.
    Though I’ve never read it myself, Mission of Gravity was considered Hal Clement’s best work, and Mesklin the type example of Hal Clement worldbuilding. In 1960s-vintage Analogs and my intro to Lit-SF Fandom in the Seventies, you could not get away from Mission of Gravity or Mesklin references on the hard-SF side of the fandom. Mesklin was the first of Hal Clement’s “X-TREME Worlds” seeing how far he could stretch physics and planetology/environments.

    Liked by 1 person

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