I’m here in the main Science Operations Center, about a kilometer northwest of the University of Arizona’s main campus. And the center point of this center is the Payload Instrument Testbed, or PIT, as everyone here calls it. It is a near body double of the actual lander. “This is the last place all the instruments get together and get to play together,” says PIT manager Rick McCloskey, who really needs to start calling himself the PIT boss.

Many of its instruments are fully functioning, hi-tech spares, such as the main stereo camera. Others are decidedly low-tech, such as the gold-painted plates that serve as the lander feet. For months, the scientists have been practicing what they call ORTs – operational readiness tests – by sending commands to all of the instruments and watching the expected responses. (Get used to the acronyms – everyone here loves ‘em.)

McCloskey wanted to make sure that the environment was completely Mars-like, so he got help from the University of Arizona’s theater department, which stitched together some painted canvas tarps and painted up some big styrofoam boulders, along with nearby scavenged rocks. “Tucson and Mars look a lot alike so it’s not too hard of a job for us,” says McCloskey.

The stage is also set with panoramic photographs from the Mars Exploration rovers. But as soon as the Phoenix lands, they will change the stage to reflect exactly what the lander is seeing. Rocks will be moved into place, the rover panoramas will be replaced by what Phoenix sees, and McCloskey will move a bright stage light, set on a tall mast, to mimic the position of the sun.

If Phoenix lands on a small rock and is tilted, then the PIT team will tilt the testbed, too. This is all to help the scientists envision the exact environment of Phoenix.

Some of the important ORTs were tests with the robotic arm, McCloskey says. McCloskey made two sandboxes, one 30 centimeters deep, the other 60, so the arm could actually dig. He says they even spent $1,500, just to ship in some crushed reddish rock from California that had the texture and color of Mars soil. They call it baghouse dust. And it has, unintentionally, helped with the overall trompe l’oeil. McCloskey pointed to a thick layer of dust on the PIT model’s solar arrays. “That’s not simulated,” McCloskey says. “That’s just dust that’s accumulated from this baghouse stuff.”