Patrick McGarey
Notes by Paul Fischer
PEDALS
Passively Expanding Dipole Array for Lunar Sounding
Develop a mission architecture for a low-cost roll- out antenna array to conduct a multi resolution multi path survey of the moons crustal stratigraphy
Multi static radar probing from the regolith through the crust
Better integration time, noise and resolution v SOTA
This is accomplished by … and architecture
Stratigraphy and lateral variations tell the story of lunar formation, volcanic history and evolution and impact history
This instrument should address all aspects of stratigraphy
Configured on the fly for much greater depth than state of the art precedent
Maximum resolution of .5 m can be achieved with Pedals
Penetration depth of greater than 10m depth resolution of one meter
While at greater than 600 meters the depth resolution must be over ten meters
A number of tethers can hold dipole antennas and probe from meters to km in depth, particular aspects of the tether to share
Linear dipoles can be coupled or coliniear for multiple dipoles
No matching circuit is needed
The minimum attena length can allow no further resolution
Combining antenna to change the resonant frequency, it allows the network to tune the frequency of each
Couple able linear dipoles analysis are demonstrated in models as shown on the right
Different parts of the antennas at different times
Negative or positive instances of reactions, inductive and capacitive reactions on the right
Behavior of the antenna across frequency, now lets consider the methods for deployment
Low mass
Volume efficient
Robust to obstacles
Long distances
The system must be elastic and that means a passive system, like a roll of tape that unrolls naturally, whether we are unrolling or unspooling or unfolding like a scaffold
Ever played with a tape measure and let it rip, the rate limiter or controlled approach
Stability controls - damping/friction
Contacted by a company that makes coinable booms that loaned a sample
How likely that pedal will encounter an imassable rock?
Use of a formula to find what number of rocks might represent there
What is the probability for success? Think about it like 100 m
Almost four km or we need to design/plan for obstacle avoidance
Test a coilable boom design from opterus
Q: what are the biggest challenges with obstacle avoidance?
A: the primary thing is that idea of not wanting to avoid rocks, just have this thing happen passively… significantly offset the science goals, for instance use the tape with something like an outrigger vs. the tape just unrolling itself, we would id all of those trades for a future mission
Q: Loop design?
A: same thing, but a substrate of the tether, essentially three tethers where the sun can be used to unroll them, in any geometry that you actually want, even a meter wide. The challenge is how to imprint that loop on that tape vs. tune the frequency… fixed resonant frequency
Q: boom arms is there room for that here?
A: the boom is complementary it is essentially our tape, the idea of reaching our distances is what we are both after, this is where the NIAC community would share our identities and there is encouragement to see what to do next with it
Q: large rocks and according adjustments?
A: a nice way to do it would be to stick the payload on the lunar lander as the train is coming down, no way to stop either of these from happening…
Q: deployment?
A: might be beneficial to have a loop and be with them passively and touch the surface of what these things could do
Q: the way that dipoles and radars work,
A: if you have a void you have an absence of material and the Pavone mission to explore the lunar cave, we don’t know that it is a cave
Q: goals?
A: cost effective and minimally robust, looking at the lunar swirl area on minor gamma, we want simple awesome science
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