At 1:00 p.m. on Wednesday, Surveyor's flight computer activated a 53-Watt heater in the Mars Orbiter Camera that will bake the instrument's epoxy structure with the goal of removing residual moisture. Without a bakeout period, the moisture in the camera's tube- like structure will leak into space at a slow rate and cause its length to gradually change. As a consequence, this tiny, slow-rate change in the structure's length would result in a gradual shift in the focus of the camera. The goal of the 14-day bakeout period is to remove all of the moisture at once and stabilize the focus of the camera.
Later in the afternoon on Wednesday, the flight team commanded Surveyor to perform the first of three solar array "wiggle tests" that occurred this week. Once per day on Wednesday, Thursday, and Friday, the gimbal joint holding the -Y panel to the spacecraft was commanded to "wiggle" the panel back and forth several times over a period of 84 seconds. During the tests, the -Y panel inner hinge moved by 8 degrees before returning to its pre-test position.
Similar to the five "wiggle tests" performed in December, the Wednesday test was performed with the solar panels in the normal orientation used during the cruise phase of the mission. On Thursday and Friday, the tests were performed with the solar panels rotated into a position representative of that used during an engine firing and aerobraking, respectively.
The flight team examined telemetry transmitted back to Earth to study the nature of the vibrations in the spacecraft that resulted from the "wiggling." The data will provide valuable insight into determining the best method to clear the broken damper arm that is wedged in the hinge joint holding the panel to the spacecraft. This wedged condition is keeping the -Y panel 20.5 degrees from its proper position.
One option under study is to combine a "wiggle test" with a small firing of Surveyor's main rocket engine. The idea is that the wiggling will move the solar panel and allow the rocket engine to provide the force needed to dislodge the damper arm from the hinge joint. However, no decision has been made at this time.
After a mission elapsed time of 78 days from launch, Surveyor is 17.52 million kilometers from the Earth, 125.97 million kilometers from Mars, and is moving in an orbit around the Sun with a velocity of 30.35 kilometers per second. This orbit will intercept Mars on September 12th, 1997. All systems on the spacecraft continue to be in excellent condition.