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Venus Rover

January 17, 2022

Early in my career, I enjoyed having lunch with my older scientist and engineer co-workers. They always regaled the lunch group with arcane knowledge from their careers that's not found in textbooks. In one case, an electrical engineer who spent his entire career designing vacuum tube circuitry told us about how one radio receiver was designed in a way to reduce its vacuum tube count by one. Since radio frequencies are much higher than audio frequencies, a single triode amplifier with proper filtering was used to amplify both types of signals without their interacting with each other.

I was also introduced to the concept of fluidic amplification by an aerospace engineer who actually worked with fluidic amplifiers. Although I had once used the strange electrical amplifier called a saturable-core reactor, I had never heard of an amplifier that didn't involve electrons. Aside from amplification, digital logic can be done by fluidics, so it's possible to build simple computers without electronics. One disadvantage of fluidic circuitry is that it operates at low speed. However, it has the advantages of being radiation resistant and working at higher temperatures than electronics; and, nanotechnology allows designs with high complexity.

Fludic amplifier from US Patent no. 4,000,757

Fluidic amplifier design from figs. 1 and 4 of US Patent no. 4,000,757, "High gain fluid amplifier," of Peter A. Freeman, April 1, 1977.[1] The fluid (air, water, or an hydraulic fluid) enters at the bottom, and the control ports C1 or C2 can deflect the stream to exit at output ports O1 or O2. The control streams can be much weaker than the deflected stream, so the device has gain. The operating principle is the Coandă effect, which is the tendency of a fluid jet to stay attached to a convex surface and entrain fluid from the surroundings. (Via Google Patents. Click for larger image.)


The short history of electronic and fluidic computers pales in comparison with the reign of mechanical computers. An early example is the Antikythera mechanism (c. 150 BC), an ancient Greek orrery, a mechanical analog computer discovered in an ancient shipwreck. In more modern times, Blaise Pascal (1623-1662) designed his Pascaline calculator that had the capability to add and subtract two numbers, and to perform multiplication and division through repeated addition or subtraction.

A short time later Leibniz (1646-1716) invented his similar stepped reckoner in 1672. Leibniz was apparently inspired by a pedometer, and he studied Pascal's machine from Pascal's Pensées. Instead of the gears of Pascal's machine, this device used a stepped cylinder. Quite a while later, in the 1820s, Charles Babbage (1791-1871) created his difference engine, a mechanical calculator designed to compute polynomial functions. The father of information theory, Claude Shannon (1916-2001), was inspired to create the 1961 Minivac 601 Digital Computer Kit, an electromechanical digital computer system intended as an educational toy (see figure).

Claude E. Shannon and the Minivac 601 Digital Computer Kit

The Minivac 601 Digital Computer Kit and its creator, Claude Shannon (1916-2001). Shannon is shown demonstrating a maze-solving mouse, called Theseus. The necessary computation and memory operations for Theseus were done using electromechanical relays. (Left, the Minivac 601, via Wikimedia Commons. Right, still image from a YouTube video by BinarycoreMedia, April 30, 2013, modified for artistic effect.)


We're now accustomed to having extremely functional scientific rovers, and even a helicopter, on Mars. environmental conditions on Mars are not that extreme, so ruggedized versions of terrestrial motors and electronics are all that are needed to enable their functionality. Having a rover on Venus is another thing altogether. While Martian temperature is in the range around 210 K (-63 °C), and its surface pressure is about 0.636 kPa (0.00628 atm), Venus is a torrid 737 K (464 °C) with an oppressive surface pressure of 9.3 MPa (92 atm). Alternatives to electronics are one way to facilitate a Venus rover that's resistant to such temperature.

A possible wind-powered Venus rover.

An illustration of a concept for a possible wind powered "Automaton Rover for Extreme Environments" on Venus.

The surface winds of Venus are just a few miles per hour, but the density of the atmosphere of Venus gives these winds a high momentum; so, they would drive a wind turbine.

(NASA/JPL-Caltech image. Click for larger image.)


In early 2020, NASA announced a contest called Exploring Hell: Avoiding Obstacles on a Clockwork Rover for design ideas for an obstacle avoidance sensor for a Venus rover, with a first-place prize of $15,000, a second-place prize of $10,000, and a third place prize of $5,000.[2-4] The contest was for a non-electronic sensor for a NASA-JPL concept rover called an Automaton Rover for Extreme Environments (AREE), the principal investigator of which is Jonathan Sauder, a senior mechatronics engineer.[2] The AREE is powered by wind, and it's intended to collect data at the Venusian surface over a period of months.[2] Submissions were accepted through May 29, 2020, and winners have been recently announced.[2-3] It's been more than half a century since the first Venus landing by the Soviet Venera 7 mission on December 15, 1970.[3] I wrote about the Soviet Venera program is an earlier article (Veiled Venus, October 8, 2014)

The idea for a mechatronic steampunk rover built from high-temperature steel and titanium, collecting power from wind and storing it in a torsion spring, came to Sauder several years ago during a work break with JPL colleagues.[3] His prototype, now at one quarter scale, wouldn't be part of a Venus mission for at least a decade.[3] A wind turbine power source was chosen, since other options are not feasible.[3] Venusian clouds make solar power impractical, and a radioisotope thermoelectric generator can't eliminate heat to the torrid Venusian environment.[3] The wind turbine would store power in a spring and directly drive the rover wheels.[3-4] This would allow the rover to travel 300 meters per day in three 100 meter bursts.[4]

Initially, the Venus rover was imagined as being totally non-electronic. Various approaches were considered for data recovery, including engraving data onto metal disks that would be launched into space by hydrogen-filled balloons, and using radar retroreflectors.[4] These methods were rejected in favor of conventional radio, but typical radio electronics will only tolerate temperatures up to 125 °C.[4] While vacuum tubes will operate at high temperature, it's difficult to maintain a vacuum against Venusian pressures.[4] Fortunately, the NASA's Glenn Research Center has been developing silicon carbide electronics that are operable at high temperature and capable of transmitting megabits of data daily.[4] One area that still needs development is a high temperature camera.[3]

As for the Exploring Hell: Avoiding Obstacles on a Clockwork Rover, 572 entries were submitted from 82 countries.[5] The first place prize was awarded to Youssef Ghali from Cairo, Egypt, for his "Venus Feelers" concept (see figure).[5,7]

Venus Feelers by Youssef Ghali

A rendering of the first-place winning concept for the "Exploring Hell: Avoiding Obstacles on a Clockwork Rover" contest - "Venus Feelers" by Youssef Ghali from Cairo, Egypt.[5]

(NASA/HeroX/Youssef Ghali image. Click for larger image.)


References:

  1. Peter A. Freeman, "High gain fluid amplifier," US Patent No. 4,000,757. April 1, 1977.
  2. Matthew Segal and Clare A. Skelly, "NASA Wants Your Help Designing a Venus Rover Concept," NASA Jet Propulsion Laboratory Press Release 2020-038, February 21, 2020.
  3. Adam Mann, "The Steampunk Rover Concept That Could Help Explore Venus," Wired. December 15, 2020.
  4. Rob Banino, "Venus rover: a new mission to land on the hellish planet," BBC Sky At Night Magazine, July 9, 2020.
  5. Ian J. O'Neill and Clare Skelly, "NASA's Venus Rover Challenge Winners Announced," NASA Jet Propulsion Laboratory Press Release 2020-123, July 6, 2020.
  6. Automaton Rover Prototype Test at Room Temperature, YouTube Video by JPLraw, September 14, 2020.
  7. Venus Feelers, Obstacle Avoidance Sensor, YouTube Video by Youssef Ghali, July 13, 2020.