The Solar System has been a busy place in recent years, with missions to a diverse range of worlds, from Mars, Jupiter and Saturn to distant Pluto and even comets and asteroids. Most of these have been NASA spacecraft, which continues to lay the path to exploring such distant places. There are, however, some places which have been visited in the past, decades ago, but now are seemingly no longer a priority, such as Uranus and Neptune. But there is another planet which is actually Earth’s closest neighbor, yet was only last visited in the 1970s and 1980s, by American and Soviet spacecraft – Venus.
Why is that? Let’s look at why Venus deserves a return visit by NASA and how new technology can help make that happen.
Being Earth’s closest planetary neighbor, it might seem logical that it would be the target for repeat missions, and it is a fascinating world, but there are problems.
Venus is well known for not having the most life-friendly conditions on its surface, and could be accurately described as a hell-hole. From space, it looks rather serene, with its perpetual cloud cover shining in the sunlight. But below, the surface pressure is about 90 times that of Earth, equivalent to about 2,953 feet (900 meters) deep in the oceans, and the temperatures are searing at about 863 °F (462 °C), “hot enough to melt lead” as the saying goes. The choking atmosphere is mostly carbon dioxide, which traps the heat from the Sun like a runaway greenhouse effect, planet-wide. The clouds also create sulfuric acid rain. It’s not the kind of place where, at least on the surface, one would expect to find any kind of life.
The harsh conditions are the main reason why return missions have dropped out of favor in recent years, in two ways. First, because it became apparent that finding any signs of life would be extremely unlikely at best, and second, the heat, pressure and toxicity made it very difficult to land a probe and have it survive for any significant length of time. Orbiters had been able to view the surface from above using radar to penetrate the thick cloud cover, but as with Mars, what would be even better in many ways would be a lander or rover.
The only landers on Venus so far have been the Soviet Venera and Vega landers from the 1970s and 1980s. They survived on the surface for durations ranging from 23 minutes to about two hours. They collected huge amounts of data and returned amazing ages of the bleak alien surface, but after that, no other spacecraft has been sent to land on the planet – the last landing was in 1985.
There have been orbiters and flyby missions, but no more landers as of yet. NASA did obtain additional data in 1978 with the Pioneer Venus project that consisted of two separate missions: the Pioneer Venus Orbiter and the Pioneer Venus Multiprobe. The European Space Agency’s Venus Express orbited Venus and studied its atmosphere from 2006 – 2014. As of now, there is only one spacecraft at Venus, Japan’s Akatsuki, which has been in a highly elliptical orbit since December 7, 2015.
There are many planetary scientists who would love to go back to Venus with new landers or even rovers. Even if Venus is devoid of life, it still provides enormous information about rocky planets in general, and Venus is almost the exact same size as Earth. It would help scientists understand how some such worlds could evolve to become habitable, such as Earth or possibly Mars, while others go in the opposite direction. This could also apply to exoplanets, since a growing number of rocky, Earth-sized worlds are now being discovered orbiting distant stars. Venus also has large volcanoes, some of which may still be active. It may also have once had oceans of carbon dioxide.
Data gathered so far by various probes has suggested that Venus may have had oceans early in its history, with much more habitable conditions possible on the surface. So what happened to turn Venus into the toxic landscape we see today, and could the same thing happen to Earth?
There is also the possibility, even if it seems unlikely, that some form of microscopic life could still exist on Venus, but high up in the atmosphere. At about 50 kilometers altitude, the pressure and temperature are similar to that on Earth’s surface. It has even been suggested that dark streaks of as-yet unknown particles, about the size of bacteria, could be microbes floating in the atmosphere. The streaks absorb ultraviolet light. Another NASA orbiter could study the streaks and find out what they are actually composed of. Microbes are only one possibility, but it would certainly be worth a closer look and would help scientists learn more about current conditions on Venus, whatever the explanation turned out to be.
“These are questions that haven’t been fully explored yet and I’m shouting as loud as I can saying that we need to explore them,” said Sanjay Limaye, an atmospheric scientist from the University of Wisconsin, Madison and a former chair of NASA’s Venus Exploration Analysis Group (VEXAG).
But a lot of scientists would like to be on Venus’ surface again, with a lander that could survive longer than its predecessors and do more science observations. Now, a team of scientists at NASA’s Glenn Research Center in Cleveland have completed a demonstration of new electronics technology that could allow just such a mission to happen.
“With further technology development, such electronics could drastically improve Venus lander designs and mission concepts, enabling the first long-duration missions to the surface of Venus,” said Phil Neudeck, lead electronics engineer of the project.
On previous landers, the electronics had to be protected by thermal and pressure-resistant vessels, which can only last for a few hours in the extreme conditions. They also add mass and expense to the mission.
“We demonstrated vastly longer electrical operation with chips directly exposed – no cooling and no protective chip packaging – to a high-fidelity physical and chemical reproduction of Venus’ surface atmosphere,” Neudeck said. “And both integrated circuits still worked after the end of the test.”
Such advanced chips could help Venus lander missions to last longer, up to weeks, and be able to conduct more science observations.
“This work not only enables the potential for new science in extended Venus surface and other planetary exploration, but it also has potentially significant impact for a range of Earth relevant applications, such as in aircraft engines to enable new capabilities, improve operations, and reduce emissions,” said Gary Hunter, principle investigator for the new electronics development.
The researchers created interconnects – tiny wires connecting transistors and other components together – which can survive Venus’ surface conditions for much longer. They can work without need of a pressure vessel, cooling system or other protection.
The new paper describing the advanced chips in detail is available here. From the abstract:
“The prolonged operation of semiconductor integrated circuits (ICs) needed for long-duration exploration of the surface of Venus has proven insurmountably challenging to date due to the ∼ 460 °C, ∼ 9.4 MPa caustic environment. Past and planned Venus landers have been limited to a few hours of surface operation, even when IC electronics needed for basic lander operation are protected with heavily cumbersome pressure vessels and cooling measures. Here we demonstrate vastly longer (weeks) electrical operation of two silicon carbide (4H-SiC) junction field effect transistor (JFET) ring oscillator ICs tested with chips directly exposed (no cooling and no protective chip packaging) to a high-fidelity physical and chemical reproduction of Venus’ surface atmosphere. This represents more than 100-fold extension of demonstrated Venus environment electronics durability. With further technology maturation, such SiC IC electronics could drastically improve Venus lander designs and mission concepts, fundamentally enabling long-duration enhanced missions to the surface of Venus.”
In 2015, NASA also awarded two grants to Ozark Integrated Circuits Inc., affiliated with the University of Arkansas, to develop silicon carbide circuits for a future rover called the Venus Landsailing Rover.
“Silicon carbide is a semiconductor that is ideally suited for the extreme environments found on Venus,” said Matt Francis, Ozark IC’s president and chief executive officer. “We have many years of experience working with this semiconductor fabrication process, developing models and process-design kits specifically for this process.”
“We will demonstrate the feasibility of creating these needed integrated circuits,” Francis noted. “We will also generate a commercial feasibility analysis based on projections of the manufacturing costs for each of these integrated circuits.”
The rover would be designed specifically for Venus’ environment, with a “sail” on top. Surface winds on Venus are low – typically under one meter per second – but the strong atmospheric pressure would create the force needed to move the rover.
Two new NASA Venus missions had been proposed as part of NASA’s Discovery Program, but unfortunately did not make the cut. These were The Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging (DAVINCI) mission, which would have studied the chemical composition of Venus’ atmosphere during a 63-minute descent. The Venus Emissivity, Radio Science, InSAR, Topography, and Spectroscopy (VERITAS) mission would have produced global, high-resolution topography and imaging of Venus’ surface and produced the first maps of deformation and global surface composition.
Instead, the two missions chosen, called Lucy and Psyche, will visit asteroids which have never been seen up close: multiple Trojan asteroids which share Jupiter’s orbit and the unusual metal asteroid 16 Psyche.
Another new Venus mission is still possible as a part of NASA’s upcoming New Frontiers missions, however, which has a per-mission budget of up to $850 million. The Discovery Program missions are capped at $450 million. Other tentative plans call for future balloons or airplanes, such as one being developed by Northrop Grumman, which could fly through the thick atmosphere.
“Northrop Grumman is currently performing research on an unmanned concept vehicle called the Venus Atmospheric Maneuverable Platform (VAMP). VAMP is a very large, but incredibly light inflatable aircraft that integrates Northrop Grumman’s diverse capabilities in deployables, unmanned aircraft, semi-buoyant vehicles, and space exploration into a unique planetary exploration vehicle. Using a combination of powered flight and passive floating, VAMP will be capable of staying aloft for long periods of time collecting vital data about Venus and its atmosphere. After reaching Venus’ orbit aboard a carrier spacecraft, VAMP will deploy and inflate with a buoyant gas. With a wingspan of approximately 150 feet and 100 pounds of payload carrying capability, VAMP will be able to cruise through the Venus skies at altitudes between 31 and 43 miles (55 and 70 kilometers) for several months to a year.”
Although no new missions have been firmly planned yet, it seems that the technology is certainly now advanced enough to not only orbit but land on Venus again for a longer visit. When that will happen is not yet known, but hopefully sometime in the relatively near future. Only then can we start to really understand how Venus was perhaps once more Earth-like, only to later become the hellish world that it is today.