Operation Moon Rocket

A grim bargain with death.
America's astronauts were the targets. Four had been killed so far - with their murderers conveniently found dead just a few hours later.
The enemy was known. Red China. But China's mastermind in the US was a mystery. There were five possibilities.
Dr. Joy Sun, the beautiful NASA scientist, with a voracious sexual appetite...Alex Simian, the multi-millionaire, with the strange "friends" in China...Major Sollitz, the career officer, with luxurious tastes his meeger salary ouldn't staisfy...Candy Sweet, the sensuous playgirl, with a lust for bizarre kicks...Reno Tree, the crippled hood, with ambitions to take over a Mafia empire.
One of them was in the pay of Red China. But which one? Nick Carter could only wait - with himself as the bait.
Killmaster had made his usual bargain with death!