Looking back through the scope at the station, this time he saw that the beacon light next to the exit had turned from red to green, indicating that the air inside the air lock had been emptied. Immediately afterward, the hatch slid open and a group of figures wearing white space suits filed out. There were about thirty of them. As they flew off in a group, the shadow they cast on the outer wall of Yellow River Station expanded.

They had to fly a considerable distance to fit the entire station into frame, but before long they slowed down and began their weightless lineup under the photographer’s direction. By now the sun had sunk by two-thirds. The remainder looked like a luminous object inlaid into the Earth above a smooth sea mirror that was half blue and half orange-red, its top covered by sun-soaked clouds that looked like pink feathers.

As the light dropped in intensity, the people in the distant group photo began to turn their visors transparent, revealing the faces in the helmets. Zhang Beihai increased his scope’s focal length and quickly found his targets. Just as he had expected, due to their rank, they were in the center of the front row.

He released the scope, leaving it suspended in front of him, and with his left hand he twisted the metal retaining ring of his right glove to detach it. Now that his right hand was wearing just a thin cloth glove, he immediately felt the minus-one-hundred-degree temperature of space, so to avoid a quick freeze he turned his body to an angle that let the weak sunlight shine on his hand. He extended the hand into a side pocket of his suit and withdrew a pistol and two magazines. Then, with his left hand, he grasped the floating scope and affixed it to the pistol. The scope had been a rifle sight that he had modified with a magnetic attachment so it could be used on a pistol.

The vast majority of firearms on Earth could shoot in space. The vacuum was not a problem, because the bullet’s propellant contained its own oxidizer, but you did need to worry about the temperature of space: Both extremes differed greatly from atmospheric temperatures and had the potential to affect the gun and ammunition, so he was afraid to leave the pistol and magazines exposed for too long. To shorten that time, over the past three months he had drilled repeatedly in taking out the gun, mounting the sight, and changing magazines.

He started to aim, and captured his first target in the cross hairs of the scope.