Payload Concept Proposal
The Heat Seekers
West Point High School team 2
Proposal
Mercury Lander Mission
Spring 2012
1.0 Introduction
Mercury is one of the least explored planets in our solar system due to its extreme temperature and lack of
atmosphere. Penetrators are science instruments designed to reach and collect data from below the surface
of a planetary body. The Heat Seekers had designed a payload, the RIPP, to detach off the Mercury
Lander Mission and use penetrators to submerge into the regolith. The payloads name originated from the
acronym Regolith Insulation Properties Penetrator.
2.0 Science Objective and Instrumentation
Regolith is defined as a lose layer of heterogeneous material covering solid rock. It includes dust, soil,
broken rock and other related materials. According to the Regolith Insulation Properties, what is the exact
depth that the regolith of Mercury is insulated? To find this we are using the following instruments: The
hull of the payload is made up of carbon fiber reinforced plastic and its purpose is for protection. We are
using two thermocouples; their purpose is to collect temperature readings at different depths. The DLR
mole’s purpose is to slowly dig into the ground. The UHF band antenna’s purpose is to send data to Earth
as it is taken. The purpose of the lithium ion battery is to power the penetrators.
Table 1. Science Traceability Matrix (Draft)
Science Objective
observe temperature
calculate distance
Measurement Objective
temperature
distance
Instrument
thermocouples
accelerometer
Mass (kg)
0.041
0.031
Measurement Requirement
-143 C to 425 C
until the regolith becomes
thermal
Instrument Selected
thermocouples
accelerometer
Table 2. Instrument Required Resources (Draft)
Power (W)
.005
0.000036
Volume (cm3)
0.536832
0.26
Data Rate (bps)
32
17
3.0 Alternative Concepts
The first concept: When the Mercury Lander Mission is approaching Mercury, we will launch our
payload from the side, where it will slowly begin to turn in a downward motion. As it is approaching the
surface, the mass of the nose will force it to fall vertically. When it penetrates the ground, the device will
go to a depth of two feet so that the wings will fold inward. After submerging, the DLR mole will begin
to travel deeper. This is caused by an “in and out” movement of the payloads nose, which penetrates
through rock and soil. While traveling, the thermocouples test the temperature of the soil and the depth at
which it becomes thermal.
The second concept: While the Mercury Lander Mission is in orbit around Mercury, the payload will be
launched from a carrier with propulsion devices holding the penetrators. Four penetrators will be
launched at around 300-500 meters per second. The propulsion devices will detach before the penetrators
hit the surface. Once they submerge under the crust, the devices will begin to take temperature reading.
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Proposal
Mercury Lander Mission
Spring 2012
Figure 1. Group 1 Concept
Figure 2. Group 2 Concept
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Proposal
Mercury Lander Mission
Spring 2012
4.0 Decision Analysis
Our Decision Analysis is what we feel is best suited for our mission specifically. Mass is very important,
because it is critical to keep the overall mass under the limit of 5 kilograms. Durability is another big
issue; it has to be able to withstand temperature and the atmosphere of Mercury. Power is a main point;
therefore, we will have power from a Lithium Ion battery. Accuracy and Precision are a focus for data
purposes. Finally, design is to meet all requirements and perform efficiently.
Figure of Merit
Mass
Durability
Power
Accuracy and Precision
Design
Totals:
Table 5. Payload Decision Analysis
Weight
Group 1 Concept
3
9
9
9
1
3
9
9
1
9
201
Group 2 Concept
3
3
9
3
3
75
5.0 Payload Concept of Operations
We are going to Mercury, and our payload is being carried on the Mercury Lander Mission. We are
going to drop our penetrator from the side of the lander form a barrel with embedded grooves, giving it a
rifling effect. As it reaches the surface of Mercury the DLR mole will begin to dig into the regolith. When
it penetrates the thermocouples will test the temperature of the soil.
Figure 3. Payload Concept of Operations
6.0 Engineering Analysis
We used the formula D = 0.000018SN(m/A)0.7(V-30.5) to solve for velocity. We need to hit the surface
of Mercury at a velocity that will allow our penetrator to submerge a depth of 0.4 meters. We found this
velocity to be 107.43 meters per second. Then, we plugged the velocity into the formula Vf2 = Vi2 + 2ad
to solve for the height from which the penetrator needs to be dropped. We found that 1,547 meters is the
accurate height for the penetrator to be dropped from the lander.
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Proposal
Mercury Lander Mission
Spring 2012
7.0 Final Design
When the Mercury Mission Lander is at precisely 1547 meters above the surface of Mercury, our payload
will release the RIPP. The barrel from which it is dropped will have grooves that two small pins, sticking
out from the top of the penetrator, will follow to cause a rifling effect during decent. The pins, however,
will lock inside of the penetrator when it exits the barrel. The penetrator will submerge approximately 0.4
meters. Then the DLR mole will begin to dig into the regolith while the accelerometer calculates the
distance traveled. Four thermocouples, which are embedded into the carbon fiber reinforced plastic, will
then begin testing the temperature of the soil. The data is then transferred from the CPU and transponder
to the lander.
Dimensions: The penetrator has a complete length of 40 centimeters. The nose of the penetrator is
approximately one fourth of the length, 10 centimeters. The diameter of the penetrator is 7.5 centimeters.
Figure 4. Payload Final Design
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Proposal
Mercury Lander Mission
Spring 2012
Final Design Mass and Power Budget
Component
Thermocouples
DLR mole
Transponder
CPU
Battery (Saft MPS176065
LI-Ion Cell )
Accelerometer
Hull
Barrel
Number
4
1
1
1
1
1
1
1
Mass (kg)
0.041
1.179
0.05
0.068
0.15
Power (W)
0.005
2.0
2.0
0.066
+20wph
0.031
1.358
1.817
0.000036
-
Totals
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Total Mass (kg)
0.164
1.179
0.05
0.068
0.15
Total Power (W)
0.02
2.0
2.0
0.066
+20wph
0.031
1.358
1.817
0.000036
-
4.817
4.086036