LANDING STATION & PROPULSION

CONSTRUCTION and electronics

Command and Data Handling(C&DH)

Since this is a bent-pipe transponder, most of the communication handling is at low power, a slower C&DH can be used. The MIP405 CPU board is used. It runs at 266MHz and will be ported with Linux operating system. The C&DH board can be found HERE.

Structure and Component Locations

The size of the chamber in the carrier is the main constraint that determines the size and shape of the lander. The allowed space in the carrier is 1.5m in diameter. The chamber is a conical shape on top with total height of 3.81m as seen in Figure 3. Figure 4 and Figure 5 gives a diagram of the locations of the different components on the lander.

Figure 3: Allotted space within the carrier for the lander.

Figure 4: Lander component locations

Figure 5: Lander view in CAD

Beam and metal sheets

1/16” thick Aluminum 6061 panel will be mounted in between solid aluminum field beams with dimensions as in Figure6. The total amount of alloy sheets and beams are calculated in Table 3. The specifications of this material can be found HERE.

Material

Aluminum Alloy

Density (g/cc)

2.7

Hollow beam length (m)

20.34

1/16" thick sheets area (m²)

5.10

Beam Weight (kg)

1.64

Sheet Weight (kg)

8.09

Total Structure Weight

9.74

Table 3: Calculation of Aluminum 6061 used.

Figure 6: Beam for lander frame

Propulsion Layer

The size, shape, and weight of the lander is greatly limited by the propulsion subsystem especially the fuel. Numerous iterative calculations were done to minimize the weight and dimensions of the lander before reaching conclusion of the size of the lander. The base of the structure would need to be 1.2 meters in diameter to contain the propulsion system. An octagonal shaped structure was used since it fits well inside the carrier. The dimensions of the fuel layer are shown below. The top cover of the fuel layer is a honeycombed structure to reduce weight as seen in Figure 7.

Figure 7: Honey combed sheet for top of propulsion layer

Payload Layer

On top of the fuel layer is the payload layer. The rover, battery, communication systems, altitude control ,and the command and data handling (C&DH) unit would be secured in this section. Since the payload does not take up less space a tapered octogonal polygon shaped is used as seen in Figure 5 to reduce weight.

ROVER RAMP

The rover exits this layer with a door on the side with and extendable ramp. RE-max 21 was used for the motor. The details of the product can be found HERE.

CAMERAS

A set to keep track of navigation four cameras are place on the sides around the payload layer of the lander. Refer to the “Micron MT9V125 VGA” cameras in the rover section. The link to this product can be found HERE.

SOLAR CELLS

Automatic solar tracking panels are placed on top of the lander as seen in Figure 5. There is enough space within the carrier no folding of the solar cells or antennas are needed.

DISH ANTENNA

The dish antenna extends above the solar panels on top of the lander to communicate with the Earth station.

OMNI ANTENNA

To achieve better line of sight, the Omni-directional antenna is placed on top of the lander for communication with the rover as seen in Figure 4.

TOTAL WEIGHT DISTRIBUTION

Table 4 lists the weight distribution of the lander. The dry mass is the weight of the lander with out the fuel and oxidizer. Many iterative calculations and redesigning of the orbital mechanics were done in order to reduce the fuel. The fuel totals up to approximately 550kg. The dry mass of the lander is only about 10% of total mass. The payload weight accounts for approximately 5% of the total mass. For a typical spacecraft 20-30% of the weight is the payload, but due to the small scale of our spacecraft those densities were not achieved.

Component

Weight (kg)

Ramp motor

0.8

Receiver

1.8

Transmitter

2

C&DH

5

Navigation & Altitude Guidance

3

Antennas

0.9

Solar Cells

7.42

Structure

11.6

Rover

12

Battery

1.93

Thruster + propulsion sys

14.5

Dry Mass total

60.95

MMH

215.23

N2O4

334.37

Total Mass

610.55

Table 4: Weight Distribution in Lander

COST

Table 5 gives an estimate for the for the raw cost of the lander. Notice that this does not include the cost of research and development. The power subsystem cost also includes the wiring of electronics within the lander. Please refer to the communication systems page for the communication subsystem cost.

System

Approximate Cost($)

C&DH

10,000

Nav & Alt Control

500,000

Power Subsys

20,000

Propulsion Subsys

200,000

Structure

7,000