Solar Queen Series by Andre Norton, Sherwood Smith, P.M. Griffin

First of the "Solar Queen" adventures, originally published under the pseudonym "Andrew North."

Lured by exotic gems and valuable oils, the crew of the space trader Solar Queen landed on the newly discovered planet Sargol, only to find their most ruthless competitor there ahead of them. Still they tried for fair trade, even according to the sly rules of the feline natives-- whose beauty and grace were equalled only by their determination to drive a hard bargain... moreLured by exotic gems and valuable oils, the crew of the space trader Solar Queen landed on the newly discovered planet Sargol, only to find their most ruthless competitor there ahead of them. Still they tried for fair trade, even according to the sly rules of the feline natives-- whose beauty and grace were equalled only by their determination to drive a hard bargain.But after satisfactory trading and uneventful take-off, the Solar Queen discovered a plague on board, the treacherous work of someone who'd been on Sargol. Now they are forbidden by Federation rules from landing on any inhabited planet - and their supplies are running dangerously low! less

The first two star-spanning tales of Dane Thorson and the Solar QueenAlmost half a century ago Andre Norton introduced apprentice Cargo Master Dane Thorson in Sargasso of Space and Plague Ship.Dane signed on with the independent cargo ship Solar Queen looking for a career in off-world trade. In Sargasso of Space, the Solar Queen free-traders win exclusive rights to trade with the planet Limbo, but the crew arrives to find most of its surface charred, with little sign of life... moreThe first two star-spanning tales of Dane Thorson and the Solar QueenAlmost half a century ago Andre Norton introduced apprentice Cargo Master Dane Thorson in Sargasso of Space and Plague Ship.Dane signed on with the independent cargo ship Solar Queen looking for a career in off-world trade. In Sargasso of Space, the Solar Queen free-traders win exclusive rights to trade with the planet Limbo, but the crew arrives to find most of its surface charred, with little sign of life. They find a valley with life, but others may still lurk. Worse yet, a strange force threatens to cripple the Queen. They must solve the planet's mysteries if they hope to escape with not only tradeable goods, but their lives.In Plague Ship, the Queen travels to Sargol, which promises a wealth of exquisite gems to trade-if the crew can overcome the native feline Salarikis' mistrust. But their troubles have just begun!. When a mysterious illness soon overtakes all the crew except the four youngest, the Galactic Patrol labels the Queen plagued and orders it destroyed on sight. With every ship in the galaxy searching for them, the crew have one chance to save the Solar Queen. But if their bold plan foils it would mean the end of the Solar Queen and its crew! less

The story is described as a "duel of the cosmic magicians". It involves two witch doctors who conjure up ghosts and demons against each other and might appear to be fantasy. But Norton bases the wizards' magic on the use of mildly hallucinogenic drugs, psychological manipulation and latent telepathy, which place the story within the realm of science fiction.

Trouble started early for the free-trader Solar Queen the moment cargo-master Dane Thorson collected a package for transit from Xecho to Trewsworld. What was in the package Dane did not learn until after he had been kidnapped, knocked out, and a dead man bearing his credentials had been substituted for him aboard the ship... moreTrouble started early for the free-trader Solar Queen the moment cargo-master Dane Thorson collected a package for transit from Xecho to Trewsworld. What was in the package Dane did not learn until after he had been kidnapped, knocked out, and a dead man bearing his credentials had been substituted for him aboard the ship.Efforts to find out the reasons for the mysterious switch seemed hopeless until they made the ghastly discovery that their precious cargo of alien embyos had been subjected to secret radiation, causing them to regress genetically into monster forms.Only after Dane and his fellow spacemen had endured a series of nightmare adventures on their port of call did they begin to fit the puzzle together - to realize that they had stumbled upon a criminal operation that involved a whole cluster of stars. less

The crew of the Solar Queen must face a plague of rats that threatens to decimate the ranks of the visiting spacefarers and Rael Cofort, the half-sister of their rival.

Stumbling upon an abandoned ship, Captain Jellico and the crew of the Solar Queen seize the prize and claim the right to salvage the derelict vessel, only to become the targets of a secret alien hijacking ring out to sabotage their claim.

Hesprid IV can't be that bad. Especially when it holds such a huge deposit of lucrative cielanite ore. Or so thinks Dane Thorson and the rest of the crew of the "Solar Queen, " and its new sister ship, the recently recovered derelict "North Star." The plan seems simple --make landfall, mine ore, leave.But when huge electromagnetic monsoons strike, and a strange lifeform makes deadly attacks on the miners, the mining grinds almost to a halt... moreHesprid IV can't be that bad. Especially when it holds such a huge deposit of lucrative cielanite ore. Or so thinks Dane Thorson and the rest of the crew of the "Solar Queen, " and its new sister ship, the recently recovered derelict "North Star." The plan seems simple --make landfall, mine ore, leave.But when huge electromagnetic monsoons strike, and a strange lifeform makes deadly attacks on the miners, the mining grinds almost to a halt. Then the real threat arrives: the crew of the "North Star, " long ago stranded here, wants off the planet... at any cost.It'll take every ounce of the "Solar Queen" crew's savvy and experience to make it off Hesprid IV with their lives, let alone a profit. And that's assuming they get past the pirates lying in wait on the far side of the star system... less