Lander
Structure
Eight support structures support the weight of the shell and antenna. These eight supporting structures each have a vibration isolator system, because the gimbal with two actuators (Azimuth and Elevation) generates vibration which could be recorded as a Venus quake. The vibration isolator eliminates this vibration problem.
Antenna pointing
Since we are using a high gain antenna, we need to point it efficiently to Earth in order to maximize the EIRP. The attitude control of a spacecraft is usually done with star or Sun trackers. On Venus, however, this would not be possible, because of the thick atmosphere that prevents from seeing those stars. The solution is to give to the lander the parameters received from the carrier's sensors before the entry phase, in order to have an absolute position. Then, when the lander separates, accelerometers and gyroscopes take the relay to measure the relative position and orientation of the lander until the landing. Eventually, we can compute the final orientation of the lander and deduce where to point the antenna, located on top of the insulation shell, with its gimbal structure. However, during the entire operational phase, the antenna will have to be steered in order to keep contact with Earth. That's why the onboard computer will also determine the change of orientation with time.
Navigational gyroscopes have a stability better than 1°/h [36], for a reasonable size and cost. Our lander antenna will have a HPBW of 4.4°. As a result, given the duration of the landing phase (one hour, [1]), the error will be within the antenna's pointing loss margin.
Weight
| Subsystem | Components | Weight (kg) | Reference |
|---|---|---|---|
| Lander | GPHS | 137 | [38] |
| Stirling engine system | 34 | [1] | |
| Electronics | 15 | [1] | |
| Motor | 6 | [45] | |
| Antenna | 50 | [44] | |
| Structure | 170 | [1] | |
| Seismic sensor | 2 | [4] | |
| Margin | 30 | ||
| Total | 444 |
Lander Block Diagram
