Lander Design

Shape design of the proposed lander 

The shape and design of the proposed lander is an important aspect of this mission. The size and weight can greatly influence the cost of launch when leaving Earth and the power budget for cooling once on Venus. The proposed design has two main compartments. The first pressure vessel contains the radioisotope GPHS modules that drive the Sterling engine and cooler. The second is the cooled electronics pressure vessel which houses the electronics hardware that processes and transmits the sensor data. The design of these compartments is described below.

Electronics Pressure Vessel

The proposed electronics pressure vessel is based on the model used by the NASA proposed airship [1]. However to satisfy the requirement of the proposed communication system package the proposed electronics pressure vessel is designed through scaling-up based on the similitude theory [2]. The requirement of the proposed communication system is as follows.

Table 1: Dimension

In Table 1, equivalent diameter means the diameter of sphere to enclose the communication system. To make the pressure of the vessel 1 atm, two stage insulation structures are used. The following tables compare the reference lander model to our scaled version. 

Table 2. Geometric structure of reference lander vs. proposed lander

The proportionality of dimensions is the same for both the reference model and the proposed design. This means that the proposed design has same density as the model. Therefore, we can obtain the total mass of electronic vessel from the following equations.

D_(I,proposed) is resulted from the requirement of electronic package. D_(o,Proposed) is calculated by the following based on similitude theory.

Similarly, vessel wall and insulation thicknesses of the proposed vessel can be found by scaling up sigma. Therefore, the shape design results are as follows.

Table 3: Electronics Pressure Vessel Dimensions

Radioisotope Pressure Vessel

Due to similar power requirements between our vessel and the reference model, scaling was not needed for the Radioisotope Pressure Vessel. The results are as follows.

Table 4: Radioisotope Pressure Vessel Dimensions

Conclusion 

Based on the analysis results of shape design of proposed lander, launcher is determined effectively for matching our reliable mission. 

Figure 1: Lander Design

[1]Colozza, Anthony J., "Radioisotope Stirling Engine Powered Airship for Low Altitude Operation on Venus," NASA/CR-2012-217665, NASA Glenn Research Center, Cleveland, OH, August 2012.

[2]Baker, W.E., Westine, P.S., and Dodge, F. T, "Similarity Methods in Engineering Dynamics," Elsevier Science Publishers, 1991.