Titan Helicopter and Airship Habitats in Venusian Clouds — These Aircraft Want to Fly the Skies of Alien Planets
The Martian helicopter Ingenuity proved just how viable the choice of aircraft for exploration is. Not only will Ingenuity unleash a new era of helicopters, there are already concepts for airplanes and airships to explore our Solar System.
Ingenuity, aka Ginny, fulfilled 72 flights on Mars; Source: Wikipedia
Exploring Mars via airplane
Mars is a quiet planet — not only because it lacks the ambient sound of life as we experience it on Earth, Mars’ thin atmosphere doesn’t carry sound very far. So it’s easy to think that the atmosphere is static; however, it’s much more complicated than that.
Extreme temperature variations cause atmospheric instability, with strong pressure fluctuations. Martian dust can make that only worse, especially when the planet experiences one of its famous global dust storms. During these storms, wind speeds can reach up to 100kph/62mph, only accelerated by the lack of obstruction through vegetation as we have it on Earth.
Because Mars’ atmosphere is so different from ours, it’s a challenge to build an unmanned aerial vehicle (UAV) without being able to directly test it and having to rely solely on the sophistication of technology. To test the airworthiness of UAVs, NASA’s Mars 2020 mission carried Ingenuity, the first helicopter to fly alien skies.
Ginny, as the small helicopter was affectionately called, exceeded its airworthiness — expected to last for five flights, Ginny finished a total of 72 flights before it lost a rotor blade this January. The success of Ginny means a lot; particularly, that powered flight on Mars is possible, despite its thin atmosphere.
The helicopter has fascinated the public so much that it even received its own type designation and call-sign from the International Civil Aviation Organization (ICAO)! Even the place where INGENUITY, its call-sign, first flew received its own airport designation: JZRO, for Jezero crater.
Now, post-Ginny era, engineers are already thinking about the next UAV for Mars. One of them is MAGGIE, which stands for Mars Aerial and Ground Global Intelligent Explorer. MAGGIE would be the first fixed-wing aircraft in Martian skies, powered by solar panels and 18 propellers.
Being solar-powered allows MAGGIE to generate lift easier than if it were powered by a nuclear engine, which is much heavier. What also makes MAGGIE different from Earth-aircraft is its ability for vertical take-off/landing (VTOL).
How would MAGGIE take off vertically in Mars’ thin atmosphere? That would be its flaps. In order to generate lift, aircraft on Earth deploy flaps at the trailing edge of the wing on take-off. In an average commercial airliner, the maximum flap setting is 40 degrees. MAGGIE would also make use of the lifting abilities of flaps, but its flaps would extend to 90 degrees.
What is lift?
Not only flaps help an aircraft generate lift, the secret lies in the wing design itself. Wings for Earth-aircraft are attached at a five to 10-degree angle, curved at the top and flat at the bottom. When air hits the wing, the design manipulates the airflow to create higher air pressure below the wing and lower air pressure above the wing. This allows the aircraft to generate lift. However, it’s not as easy as that — lift varies depending on the other three forces of flight: weight, thrust, and drag. Lift’s opposing force is weight; that means a Mars aircraft should have as little mass as possible. However, the vector of weight is always gravity, and Mars’ gravity is only 0.38 of Earth’s.
MAGGIE would have a range of 179km with a fully charged battery at a maximum altitude of 3200ft. In order to keep MAGGIE small, its wingspan would only be around eight meters (26ft), allowing it to fit inside a rocket. A sky crane, the kind of apparatus that safely brought Curiosity and Perseverance to the Martian surface, would allow for a soft landing of MAGGIE once it reaches the Red Planet.
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| ARES, which never made it to Mars, here seen in a concept artwork; Source: Wikipedia |
However, ideas for aircraft on Mars already existed before Ginny’s development. Take the Aerial Regional-scale Environmental Survey, ARES for short. ARES was one of the concepts submitted for a mission that ended up being the Phoenix lander.
Despite the fact that ARES didn’t make it to Mars, the idea is still an intriguing one. Basically, ARES looks like a flying stingray, powered by a rocket engine. The goal for the mission was short but would have been valuable — deploy ARES for an hour to fly through the skies of Mars to collect data about the planet’s weak magnetic field and atmosphere.
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| One of the few images from Venus' surface, taken by the Venera 13 lander; Source: 9GAG |
Airship habitats in the clouds of Venus
For the most part, space agencies have avoided exploring Venus, mostly because it’s so difficult and spacecraft must withstand extreme conditions. On this brutal world, one day is longer than one year, and the Sun rises in the west — if you could see it because clouds of sulfuric acid cover the entire Venusian skies.
Below the cloud cover you’ll find a surface temperature of 467°C/872°F and pressure reaching 93 bar — equal to being 3000ft underwater. The Venera 9 lander, the first to land on the surface of Venus and transmitted photos of this alien world, succumbed to the extreme conditions after just 53 minutes.
All of the landers touched down 40 years ago, and since then, no spacecraft has explored the Venusian surface. Currently, there’s only one active mission, and that is JAXA’s Akatsuki orbiter.
However, even though Venus is such a demonic planet, it has a lot of advantages when it comes to exploration compared to our beloved Mars. Not only is Venus often called Earth’s twin due to its size, it also has an almost equal gravity. Venus also has the advantage as being closer to Earth than Mars. Plus, look up (or down) at Venus’ skies and you’ll find an ideal area to explore.
Venus’ atmosphere gets merciful 50 to 65km (164’000 to 210’000ft) above the surface, where conditions are similar to Earth’s, even with breathable air! At this altitude, Venus’ atmosphere counts as the most Earth-like in the entire Solar System.
Given the good conditions at this height, there are a number of interesting aircraft concepts that would even include building a permanent residence in Venus’ clouds. So, if you’ve seen the Studio Ghibli movie Castle in the Sky, you’ll love this!
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| Artist's rendition of an airship habitat in Venus' atmosphere; Source: Wikipedia |
The High Altitude Venus Operational Concept, given the ominous abbreviation HAVOC, would involve five crucial steps to building a permanent human presence on Venus. In step one, an airship would be sent to Venus to test technologies and explore the conditions.
But how would we even get an airship to Venus? Effectively, it would be a blimp, inflating once it reaches the Venusian atmosphere and target altitude.
Once the airworthiness of this airship is proven, the second phase would ensue. In phase two, astronauts would go into orbit around Venus to prepare for phase three. During this step, astronauts would descend into Venus’ atmosphere for 30 Earth days in an airship 129 meters (423ft) long. The total mission duration would be 440 Earth days, including the trip to and from Venus.
In phase four, astronauts would extend their time in Venus’ sky, this time residing there for one Earth year, longer than a Venusian day and year. The last phase of HAVOC would involve building a permanent presence in the skies of Venus.
This would not only mark a record as flying an aircraft through Venusian skies, it would also be the first crewed aircraft on another planet!
If you’re still not convinced that this is a good idea, think of it as a kind of lunar base in Venus form. Venus is often a good target for exploration further out in the Solar System, like Mars and the gas giants, via gravity assist.
We already have evidence that flying is better than landing on Venus, found in the Vega program. Vega was a series of joint missions between the Soviet Union and several European countries in 1984. Part of the mission involved sending balloons into Venus’ atmosphere at an altitude of 50km (164’000ft). Compared to the previous Venera landers, the balloons operated for much longer, remaining functional for almost two entire days.
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| VAMP would be able to fly uninterrupted for one year. In this artist's rendition, you can see VAMP flying through the skies of the Saturn Moon Titan; Source: Space |
However, HAVOC isn’t the only idea for aircraft in Venus’ skies. Another idea is the Venus Atmospheric Maneuverable Platform (VAMP). This concept comes from Northrop Grumman and LGarde, and would involve a totally new type of aircraft — a flying wing that is inflatable.
VAMP would have the wingspan of a 767-200, but be incredibly light; just 450kg (990lbs). When VAMP flies through the dayside sky, it would be powered by solar-powered propellers and once it reaches the nightside sky, it would glide to lower altitudes.
The great thing about VAMP would be that it could operate for one Earth-year, so it would also be a semi-permanent resident of Venusian skies.
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| High contrast image taken by Huygens after it landed on Titan in 2005; Source: Wikipedia |
Helicopters on a distant moon
Titan is an intriguing world, maybe the most Earth-like in the entire Solar System. The moon orbits Saturn and is larger than the planet Mercury, and it also has an atmosphere denser than Earth’s! Look at the moon in visible light and the most you’ll see of Titan is the constant haze that enshrouds it and makes it look kind of fuzzy. However, in infrared, the details of its surface come to light.
One factor that makes Titan so reminiscient of Earth is its lakes and rivers. Well, Titan’s lakes aren’t composed of water, but of liquid methane. For that reason, the moon is also intriguing in the search for extraterrestrial life.
So far, only two spacecraft have directly studied Titan, both part of the same mission; Cassini, as it orbited Saturn between 2004 and 2017, and Huygens, which landed in the Adiri region in 2005. Huygens took the first photos from the surface of Titan, resembling a lot the first photos of Venus and Mars taken decades ago.
For the most part, Titan is an unexplored world. One challenge that every mission to the outer Solar System faces is the sheer distance from Earth. This means that autonomy is a crucial feature for every mission that aims to visit Titan.
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| NASA just announced that Dragonfly's launch is scheduled for 2028; Source: Space |
At least Titan can get excited for a robotic visitor in the early 2030s. The visitor will be Dragonfly, a quadcopter differing a lot from the small Ginny helicopter. It’s much bigger and heavier and Dragonfly will have to rely solely on batteries. Titan only receives about 0.1% of the sunlight that Earth gets due to its big distance from the Sun and thick atmosphere, meaning that the moon can be quite murky.
The VTOL aircraft will have to operate in freezing environments (-179°C/-290°F), but Titan has a significant advantage for flying compared to Mars; its dense atmosphere. Having only 14% of Earth’s gravity but a thick atmosphere, lift is much easier generated on Titan.
This means that a rotorcraft like Dragonfly can cover much more areas. The mission will last for two years, during which it will explore hundreds of kilometers of the mysterious moon.
There’s a lot to explore out there, and coming up with ideas to investigate the alien worlds out there also generates the most alien of spacecraft, from VTOL aircraft to inflatable flying wings. Ginny has started a new era, similar to how Sojourner started the age of rovers almost 30 years ago.
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