Venus grade: NASA seeks a lander battery tough enough to survive Earth's evil twin

News
By John Loeffler
published

Venus' surface is a hellish place, but that won't stop NASA's future landers from trying to explore it.

venera venus missions
The Soviet Union's Venera landers survived on Venus for a maximum of a few hours. (Image credit: NASA)

A new NASA video makes the case that Venus is Earth's "evil twin."

The nefarious moniker is revealed to be, in a way, an apt description of why astronomers will be investigating Venus this decade. Scientists and engineers from NASA and the European Space Agency are gearing up to send three new missions to the second rock from the sun. They want to know a whole lot more about the nearby planet, which resembles Earth in so many ways, and yet is so strikingly different. 

The video touches on a few nightmarish but intriguing aspects of Venus. For one, it's got a runaway greenhouse effect. The 15-mile-thick (24 kilometers) shroud of atmosphere is made of carbon dioxide and contains sulfuric acid clouds. The planet produces temperatures hot enough to melt lead. Lori Glaze, NASA's director of planetary science, said in the video that the Venusian surface can reach 900 degrees Fahrenheit (480 degrees Celsius). 

"So it is a crazy place, but really interesting," Glaze said. "And we really want to understand why Venus and Earth turned out so differently."

Related: Scientists hail 'the decade of Venus' with 3 new missions on the way

To solve the battery problem, NASA has partnered with Advanced Thermal Batteries Inc. (ATB) to develop a new high-temperature power source — and ATB researchers have already developed a promising, surprisingly hardy prototype battery.

The key to the new battery is using Venus' extreme temperature to the lander's advantage, in the form of low-discharge molten salt. This material has sufficiently high power density and is easily stored and maintained on Earth, since salt's high melting point means that it will remain solid and inert on our planet while retaining its energy potential for many years.

A major problem with molten salt batteries that already exist today is their high rates of self-discharge, caused by internal electrochemical reactions, which limits a normal thermal battery with a molten salt electrolyte to only a few hours of use on Venus. According to NASA, ATB recently developed a 17-cell battery prototype that was able to limit the battery-draining internal reactions to significantly extend the battery's life.

This enabled ATB's battery to discharge between 19 volts and 25 volts for 118 days, almost twice LLISSE's operational power requirements, before corrosion reached the positive lead on the battery.

Related stories:

— NASA's Parker Solar Probe captures stunning Venus photo during close flyby

— Photos of Venus, the mysterious planet next door

— New wave of missions to reignite Venus exploration

"This recent battery technology demonstration, with improved architecture and low self-discharge electrochemistry, is a huge accomplishment that many may have not thought possible," Kevin Wepasnick, an ATB project engineer, said in a NASA statement.

It will still be some time before NASA can feel confident that the new battery will prove itself a match for Venus' harsh environment, including developing a container and packaging that can withstand the extreme pressure and caustic nature of Venus' atmosphere. But it appears that the biggest hurdle LLISSE will have to clear has been successfully dealt with. 

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John Loeffler

 John is a science and technology journalist and Space.com contributor. He received his B.A. in English and his M.A. in Computer Science from the City University of New York, Brooklyn College, and has bylines with TechRadar, Live Science, and other publications. You can find him on Twitter at @thisdotjohn or seeking out dark sky country for spectacular views of the cosmos. 

11 Comments Comment from the forums
  • newtons_laws
    So although ATB's molten salt battery can provide power for 118 days at the very high surface temperatures on Venus (480 Celcius), how are they going to get semiconductor electronics on a lander to operate for days at those external temperatures? Using thermal insulation will only keep the heat out for a few hours. Are they going to use active cooling i.e refrigeration using a heat exchanger? I suppose for simple things like a radio transmitter/receiver circuit thay could use old style thermionic valves/tubes :laughing:
    Reply
  • Atilla De Bum
    Use thermionic material that converts heat to electricity. We already use this material in RTG (Nuclear Football 'batteries') for space probes. All electrical connections will have to be welded to be able to withstand the 1000 or so degrees.

    Old-School vacuum tubes are a viable alternative to heat sensitive semi conductors, unless they figure out how to make those delicate devices work at elevated temperatures.

    As long as the 'vacuum' tubes are not exposed to OXYGEN, they won't need to be in a Vacuum (glass) envelope to operate. Oxygen would burn out the filaments (heaters for the cathodes) . Some tests should be done in a Venus Atmosphere simulation to see if the components function and have a reasonable lifetime.

    When transistors were first invented (1960's), our military electronics teachers said not to expect to see many of them in widespread use because they can't handle any real power and are very temperature sensitive. Maybe the tide has turned?
    Reply
  • billslugg
    Thermionics would not work on Venus because they need a cold sink.
    Venus has "Hazy Day" sunlight, solar panels would work.
    Transistors don't work above 225°C (427°F). Venus is 462°C.
    Need lots of cooling, maybe a vacuum shroud.

    Diamond based transistors could possibly handle the heat. First one made about a year ago.

    https://www.tomshardware.com/news/diamond-transistors-FETS-low-power
    Reply
  • Trevorholmes
    I apologize, but I couldn't find any specific information regarding NASA seeking a lander battery tough enough to survive Venus. It's important to note that my training data only goes up until September 2021, and I don't have access to real-time information or updates on NASA's current projects or initiatives.
    However, exploring the harsh environment of Venus is indeed a topic of interest for scientists and space agencies. Venus is known for its extreme temperatures, high download pikashow apk for andriod atmospheric pressure, and corrosive atmosphere, which make it challenging for technology to withstand. If NASA or other space agencies are working on missions to Venus, it is likely that they are developing specialized equipment and technology, including batteries, that can withstand these extreme conditions.
    For the most up-to-date and accurate information on NASA's missions and initiatives, I recommend visiting NASA's official website or referring to reputable scientific sources for the latest news and developments related to Venus exploration.
    Reply
  • billslugg
    "...my training data only goes up until September 2021."
    Thar would be ChatGPT.
    Venus is known for "high download pikashow apk"?
    Venusians are into Bollywood?
    ChatGPT-3 seems to be confused.
    Reply
  • Atilla De Bum
    I know they can Radiation Harden computer chips. We used to do that at Texas Instruments back in the 70's. They may have to do a lot more work to Temperature Harden them before the Venus probe takes off. ? What's the temperature on the Surface and the temperature of the Atmosphere near the surface ? Might be enough of a ^T to allow thermionic (thermocouple) DC power generator to function. I used to build a lot of items for deep space back in the 1970's, but our concerns were Vibration on launch and the super cold temps in space.
    Reply
  • billslugg
    There is no sunshine on Venus, thus the ground is heated by the air. They would be very close to thermal equilibrium thus not suitable for thermionics.

    Radiation is not an issue as much as high heat. Noise becomes a problem in semiconductors at high temps. Germanium and silicon cannot handle 864°F, the temperature on Venus' surface. Diamond might work.
    Reply
  • newtons_laws
    In general the leakage current (which is unwanted and if too large will prevent operation) of semiconductor devices increases in proportion to e to the power of (-Δ/kT) where Δ is a band gap energy, k is Boltzmann's constant and T is absolute temperature in °K. It will be seen that for a given temperature increasing the band gap causes a big reduction in the leakage current e.g doubling the band gap reduces the leakage current to only 13.5% of the previous value. Germanium has a band gap of 0.7eV whereas Silicon is 1.1eV, which is why Silicon semiconductors can operate at higher temperatures than Germanium ones. Therefore to operate at Venusian surface temperatures you need something with significantly larger band gap than that of Silicon, Carbon (in diamond structure) has a very large band gap of 5.4eV, so if diamond based semiconductors can be made then they may well be able to cope with temperatures on Venus.
    Reply
  • newtons_laws
    Atilla De Bum said:
    Old-School vacuum tubes are a viable alternative to heat sensitive semi conductors, unless they figure out how to make those delicate devices work at elevated temperatures.

    As long as the 'vacuum' tubes are not exposed to OXYGEN, they won't need to be in a Vacuum (glass) envelope to operate. Oxygen would burn out the filaments (heaters for the cathodes) . Some tests should be done in a Venus Atmosphere simulation to see if the components function and have a reasonable lifetime.
    I don't think that's correct about the tubes not having to be in a vacuum. In order for the electrons from the cathode to travel past the grid elements to the anode they need to be able to travel freely. If they were exposed to the atmosphere of Venus( which is at a surface pressure 92 times that of Earth) the gas molecules would impede the electrons movement.
    Reply
  • billslugg
    For electrons to flow fron cathode to anode, it must be in a vacuum or else the electrons would simply ionize the gas creating a huge spark. Glass vacuum tubes would probably function function at 900°F.
    Reply