GENERAL CONCEPT & SUMMARY

The atmosphere of Venus rejects the majority of the electromagnetic spectrum; however, a small bandwidth of near-infrared rays passes through (~0.7-1.5 micrometers) and theoretically can be detected on the surface. The goal of this project is to figure out a solution to store 1 MB of data in harsh conditions on Venus in which traditional electronics do not work.

Such data will be stored in binary base. The input of the memory system will be a sole actuator coming from the mechanical computer, which would exert a push or not depending if the value to record is a high or low voltage value. The output of the memory system will be an array of 1s and 0s that can be transmitted to the orbiting satellite.

The mechanical equivalent of the 1/0 datapoints will be bi-stable switches that can store a up or down state. Such switches will have a radiation-reflecting coating on top. The switches will be contained on a flexible sheet that will be guided throughout the memory storage compartment via conveyor system (along tracks in contact with the edges of the sheet only, such that the switches themselves do not contact anything). The system will have three stations: resetting, writing and reading (in that order). The two first will consist in a group of mechanical actuators that will write an up or low state on the switches On the contrary, the reading station will consist on an optical detector that would capture light and, via optical fibers, point it and the switches. Depending on the state of such switches, light will be deflected differently, a phenomenon that can be recorded by correctly placed solar panels and translated to electrical pulses again.

The first of the strongpoints of this approach is the sole mechanical input that the system needs and the simplicity of the mechanical system that supports it; consisting only of gears and linear actuators. We stressed on the mechanical simplicity requirement. Second, the bi-stable switches are a technology reliable from a mechanical point of view and do not suffer from radiation exposure, which classically has represented a challenge for space mission memories.

SWITCH CONSTRUCTION

Using MEMS manufacturing technology, this solution proposes to create 'switches' using thermally buckled beams. Theoretically, the switches will be no larger than 50x50 microns in area, allowing a large sheet of them to be manufactured with a total area equivalent to the total number of switched desired (8e+6 switches in the case of 1 MB). The switches will be composed of titanium coated in gold manufactured on a silicon sheet. When manufactured on earth, the switches will appear flat; however, in the extreme temperatures of Venus, the switches will expand and subsequently buckle. The switches will be designed to be stable when buckled in either a convex or concave form. Each form will pertain to a bit of binary, a 0 or 1.

WRITING STATION

The writing station will consist of a series of electrical actuators (e.g. push-pull solenoids). Such actuators will indent simultaneously a 10-switch row of the bi-stable switches tape. The actuators will be triggered by a set of spring-loaded contacts, which are pressed in an up/down position directly with the linear mechanical input provided to the system.

The working principle resembles that of a typewriter: a sliding mount with the contacts will step horizontally across the width of the tape, while a leverage system will punch the contacts to lock down some springs (this would correspond to a binary 0); then, after all the 10 contacts reach their position, a mechanical device will induce a voltage input which will activate the selected contacts and switch the corresponding bi-stable bridges; finally, the mount will be set back to the starting position via a spring. This backwards motion will set all the springs back to a default position due to a mechanical indentation with the gear of the mount.

READING STATION

Radiation managing

If the infrared rays are able to be focused into a beam of small diameter, then subsequently split using fiber optic cables and a fiber optics beam splitting device (non-electrical), the infrared beams can then be focused to the top of the sheet of the switches. At a certain angle of incidence, when the switches are flipped on to the 1 position, the gold plating of the switch will reflect the infrared wave form into a specific location. When switched off, the infrared will be reflected in a different direction.

Data Reading

The reflection of the infrared rays from the switches in the on position will be reflected towards individual photo voltaic sensors, detecting the presence of a specific switch location as either on or off.

Along a certain portion of the conveyor system will be a row of indentation devices that flip every switch into the off position.

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Directly afterwards, a system of solenoids controlled by a simple circuit and a linear actuator will indent the switches in a linear fashion, registering the data in binary and allowing the photo voltaic sensors to read the condition of the switch when the infrared light is reflected (or not) towards the sensors.

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Mechanical Input

Using a 1 N and 1cm linear actuator, the entire system can be controlled by varying the input actuation distance between 0.5cm and 1cm. The use of ratchet cranks will be implemented

BIBLIOGRAPHY

Sources:

Spectroscopy of Venus https://www.hou.usra.edu/meetings/vexag2017/pdf/8006.pdf

Wilquet, V. et al. Preliminary characterization of the upper haze by SPICAV/SOIR solar occultation in UV to mid-IR onboard Venus Express, J. Geophys. Res., 114, XXXXXX, doi:10.1029/2008JE003186

Discarded ideas material:

Ferroelectric tunnel junctions: https://www.nature.com/articles/ncomms5289

https://pubs.acs.org/doi/abs/10.1021/nn401378t