For week of October 17, 1996
Spacecraft Status at KSC:
As you can see from the live KSC image, quite a lot has been accomplished over the last two weeks. The petals have been closed for the final time, the lander bolted (using separation nuts) to the "backshell interface plate" inside the backshell. Most recently, the heatshield has been bolted to the aeroshell.
These accomplishments come as a great relief to the entire team. As we and other spacecraft builders have discovered, the flight hardware is often more in danger of being damaged inadvertently by human hands than from anything the rigors of outer space could dish out! For example we had to repair a broken wind sensor in the MET mast after a ground wrist strap brushed past it, damaging a very tiny element. During the mission, nothing will come near this sensor. Fortunately, it was fixed without much trouble. Now that the bulk of the system is neatly packaged inside the backshell, at least we can breathe a partial sigh of relief.
The next step in this delicate process will be to turn the entry vehicle upside down and spin balance it at 70 rpm using a spin table in the facility. This process will remove any wobble from the mass properties. (For the technically inclined, this process aligns the principle axis of inertia with the axis of symmetry.) Once done later this week, we will flip the vehicle over again (a tricky process all by itself) and then mount the cruise stage. We will then do yet another spin balance in the launch configuration.
When we started this assembly sequence at KSC two months ago we had about 14 days of schedule "pad" in case anything slowed us down. Well of course, things did slow us down and we now have about 5 days of schedule margin left until we place the spacecraft on top of the upper stage in November. However that isn't bad considering the complexity of this operation. And we had expected to use the margin up. We are all very happy with the progress so far.
Mission Operations Status at JPL:
For the past two weeks those of us on the team working at JPL have been focused on operations. We have a "testbed" at in Pasadena that has a complete duplicate set of all of the flight electronics that are on the spacecraft (including a "sim" rover when needed). In addition to testing flight software on this testbed, we also use it in an operational mode: essentially "flying" the testbed in a simulated mission to Mars! Early last week we "launched" the testbed using the same people, procedures and software that we will use on launch day. We even used the launch team at the Cape who have been doing the electronics integration testing. Afterward we performed the instrument and rover health checks that we will perform in the weeks after launch. This week, we performed two TCMs (trajectory correction maneuvers - or "burns"). Later this week and this weekend we will "land" the testbed: actually running the "EDL" (entry descent and landing) flight software in the "testbed spacecraft". Saturday we will simulate the first day on Mars.
We are currently in the process of building up a "Mars Room" adjacent to the testbed near our operations area. This room is filled with sand and rocks and will eventually be the home of a test lander and the sim rover. Although most of the electronics will reside in the testbed a few feet away (so we can more easily access it), the lander's sensors and actuators will reside on the lander in the room. This lander will include the petals, camera, high gain antenna, airbags and rover communication antenna. The rover ramps will also be installed. In the coming months, we will use this room to simulate the first days and weeks on Mars. These simulations help us learn the finer points of operating this complex little lander and rover.
-- Rob Manning