The novel, which I read in the 1980's or so, opens with the arrival in the Sol system of a huge starship that ignores Earth and starts to refuel using way too much of Jupiter's atmosphere.

Expeditions sent to the ship discover 'trilaterally symmetrical' aliens, (the cover illustration showed them in garish yellow and red.) These aliens have a menagerie of species collected on their travels, the most recent such being small, happy-go-lucky creatures who can produce clouds of random pheromones then home in on the ones that cause sneezing fits or worse.

One group of humans is captured by the trilaterals and one of that number impresses them: he notices that the design of their ship should expose them to gamma radiation at speed, so he uses his pidgin command of the language to ask, 'How do hide from the light that kills?' They reveal to him that they are all female: males are degenerated tiny sperm donors, like our anglerfish, and ask if a kitten fulfills that role with humans.

They also have neat personal drives: pogo-stick shaped devices that shoot a laser-like beam from one end (possibly ions from fusion).

Eventually the ship leaves, but some humans and pheromonic aliens escape. In a postscript, a joint expedition to the new friends' homeworld is underway.


2 Answers 2


Is this The Jupiter Theft (1977) by Donald Moffitt...?

Front cover of "The Jupiter Theft" (1977) by Donald Moffitt.

The Wikpedia plot summary matches most of the plots points you described:

  • An alien object, travelling from the direction of Cygnus X-1, is detected entering Earth's solar system.
  • A joint Chinese-American expedition is sent to investigate.
  • The human expedition is intercepted by the aliens, dubbed 'Cygnans,' riding on matter-annihilation powered "broomsticks".
  • The humans are captured and placed in a Cygnan zoo.
  • One of the humans learns to speak the musical Cygnan language.
  • The humans discover that the Cygnans plan to use Jupiter as a fuel source.
  • The humans eventually escape the Cygnan vessel with the help of an alien prisoner and a new Cygnan Thrust System.

The initial part of the novel mixes near-future thriller and disaster novel scenarios that focusses on the discovery of a moving gamma-ray sources headed towards Earth from the direction of Cygnus X-1. The diversion of a Chinese-American joint Jupiter mission to investigate the new Solar System intruder.


The Jupiter Mission is intercepted mid-space by aliens, dubbed Cygnans, that rides on matter-annihilation powered "broomsticks".

The mission is essentially destroyed with the surviving crew taken alive as specimens for a Cygnan zoo.

Now imprisoned, the Sino-American crew attempt to contact the Cygnans and seek to discover their true purpose of appearing in this Solar System. Using a Moog synthesizer and their natural gift of perfect pitch, one of the crew learns to understand and then "speak" the Cygnan musical language.


While searching for a new home and to do so, they raided numerous star systems for Jupiter-mass "gas giant" planets to use as fuel.


A fluffy pink bird-like humanoid, 61 Cygni, was another zoo kept prisoner. 61 who helped the earthlings with escaping the Cygnans.


Their escape from the zoo required a working example of a new Cygnan Thrust System that the Sino-Americans develop into a much faster though still, barely, subluminal, and more efficient that could use passing comets to fuel this system instead of stealing entire planets.

In the book itself, the Cygnans are described as not being "bilaterally symmetrical" and are compared to starfish.

"Where’s the brain, then?" Jameson said.

"In the most sensible place, I imagine—at the top of the nerve cord. That would put it between where its shoulders would be, if it had shoulders instead of that almost-round cross section. The nerve cord probably runs through the center of the body—not dorsally, like us vertebrates, or ventrally, like terrestrial insects. Because…" Dmitri's face flushed in triumph. "Because Cygnans aren't bilaterally symmetrical. They're built on a radial plan, like hydras or starfish. They're descended from something like coelenterates, not flatworms."

The Jupiter Theft (1977) by Donald Moffitt.

It's also noted that the female Cygnans run the show, and that the male Cygnans are smaller, 'non-sentient vegetables' used purely for the exchange of gametes.

"The Cygnans are all females," Jameson said. "The ones we've been thinking of as Cygnans, I mean. What fooled me was the way they behave like courting couples. And the personality differences, and the fact that one was bigger and stronger than the other. If they’ve got to pair off to reproduce, I suppose it's natural that a weaker would tend to gravitate toward a stronger."


Dmitri laughed with sheer enjoyment. "These little males are just nonsentient vegetables," he said. "The Cygnans exchange them like engagement rings. Why didn't I see it? It took a rocket jockey like Tod here to point it out to me."


"Strange way to perpetuate a species," Omar said.

"No stranger than ours. Males aren't very important in the scheme of things. They're just a mechanism for exchanging gametes. Female spiders eat their mates when they've finished their job. This thing in my hand is a gene package, not a lover. A Cygnan's emotional equivalent of a mate is the other female she trades males with."

The Jupiter Theft (1977) by Donald Moffitt.


Based on the timeframe and subject, this is likely The Jupiter Theft (1977) by Donald Moffitt.

The original 1977 cover shows the Cygnans as hexapodal with a thick tail like a third leg coloured yellow and rust. A red-and-yellow cover was used for a 1979 edition:

Two Cygnans, as described above, each holding a broomstick, drag a bagged human in a red spacesuit against a backdrop of a ship and the arc of Jupiter A triangular spaceship burns above Jupiter, while in the foreground a metallic insectoid investigates a red structure looking like a flower made of tongues

The feathery elf-like aliens can produce any kind of scent:

"He's too much of an ox to notice," Maggie said. She turned to Jameson and said: "Smell! They tell us by smell! When they want to warn us that there are Cygnans around, they lose that nice spicy aroma and they suddenly smell sort of musty, the way Cygnans do."

Dmitri nodded vigorously. "They manufacture smells as well as detect them. They probably can imitate any smell they encounter. Make up new ones, too." He laughed delightedly. "Odors to order!"

The bit about gamma rays:

He shuddered. What was that spray of light? A waste product of the drive, as heat is the byproduct of the work done by a mechanical engine? He suspected that the Cygnan exhaust was something akin to pure gamma rays. It wouldn't do to let that stuff get too close to an inhabited planet, to say nothing of that terrible bow wave!

"How will you remain in the shadow of the light-that-kills?" he asked impulsively, improvising words and hoping his meaning was getting across.

The sticks that the Cygnans use are eventually named "broomsticks." The first sighting of them:

And then the image compensator had one of them pinned down, and Jameson caught his first glimpse of a Cygnan. It quivered on the screen, a sleek many-legged shape clinging to a stick, like a lizard on a broomstraw.

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