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Team Vision for Final Demo and Handoff

This phase our team planned to manufacture, assemble, and test our lander. We planned to test the lander according to the test plan below to determine its velocity, acceleration, and deformation of the honeycomb. We also planned to test on multiple types of surfaces and on different inclines of these surfaces.

Our team was able to accomplish these tests. However, we did not test on as many surfaces as we had hoped since we did not have enough honeycomb to use over a larger variety of surfaces. We also did not test with the surfaces as gradients for the same reason. Since we were limited on honeycomb, we wanted to complete an acceptable number of tests on one surface to analyze if those results are repeatable.

Test Results Summary

Inputs & Source

Test Plan:

We used ANSYS and Creo to carry out our lander model Simulation. The base model was created in Creo and then exported to Ansys for further analysis. The simulation results were compared with actual prototyping results to gain better understanding of our design.

Subsystem tests were performed to help make key design decisions. The first test helped in determining the optimal shape of the crushable bottom. More sub-system tests may be added in future design and prototype iterations.

This subsystem test helped in determining the best orientation of the crushable bottom. The honeycomb can be in a vertical or horizontal direction which changes how much it crushes. Therefore, the honeycomb crushable bottom was tested in both orientations to determine which can endure higher forces and energy impact.

Goal: To determine the orientation that can absorb maximum energy and endure maximum impact force.

Full System Test:

The full model simulation will be carried out on ANSYS. The goal for this simulation test will be to test landing on different surface topographies. Two main factors considered will be surface topography (flat or rocky) and Incline. Initially, we plan to test incline at 0 and 30 degrees. Depending on the results of current scenarios we plan to carry out further analysis with different values for incline.

Our goal for the full system test will be to achieve 0 final velocity. We will also be looking in-depth on the impact forces and energy consumption. More scenarios might be developed to test the effects of lander bouncing due to impact.

Outputs & Destination

The prototype was dropped from a test stand onto two of the four different Psyche surface testing beds. These testing beds have surface compositions similar to those that are expected to be found on Psyche. The first surface had a mix of metal shavings, gravel, and rocks while the second surface consisted of gravel and concrete. Knowing the mass of the lander allows for the actual Psyche projected impact velocity of 6 m/s to be matched. This was achieved by dropping the lander from a height of 6 feet. By utilizing a high speed camera and a ruler, a post-impact velocity was calculated after each test. Additional measurements to estimate forces and bounce angles were collected using an Inertial Measurement Unit.

A video of the drop can be viewed here.

The honeycomb was tested in two different orientations. The first oriented the openings of honeycomb cells in a vertical direction and was 0.5 inches tall. The second oriented the cell openings in the horizontal direction and was 2 inches thick. The lander was tested on the two different surfaces described above. Table 1 below shows the results from the experiments compared to the simulation. All simulation and experiment data are of the prototype model.

	Simulation: vertical honeycomb	Experiment 1: vertical honeycomb, metal shavings surface	Experiment 2: vertical honeycomb, metal shavings surface	Experiment 3: vertical honeycomb, gravel and concrete surface	Experiment 4: horizontal honeycomb, metal shavings surface
Deformation (%)	66	12.5	23	31.2	71.4
Post-Impact velocity (m/s)	1.7	1.05	0.85	4.66	1.69
Maximum acceleration (m/s2)	406	> 9.8	> 9.8	> 9.8	> 9.8