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There have been some pretty impressive attempts to do science on the Red Planet in recent decades and I for one have just loved the results.
It was way-back in the late 1990s when the first Martian rover landed on the dusty surface of the planet and not only kick-started the whole "planetary rover" thrust but also helped me launch 7am News. Thanks to some cunning on my part, the 7am News website was the first in the world to carry pictures from that landing, beating all the news networks and even NASA itself in getting the first images onto the web-browsers of an eager audience.
Since then of course we've had a succession of rovers which have done an unbelievable job in traversing the plains and slopes of the planet whilst performing basic science and sending back unbelievably good pictures of the surface, including stunning panoramas.
In keeping with the Earthly trend, the latest rover has even sent back a bunch of "selfies" which are remarkable in and of themselves.
However, a mission due for 2020 is designed to take this exploration and imaging technology to a whole new level.
Yes, NASA is sending a flying drone to Mars!
Okay, this won't be a quad-rotor device like the drones we're used to seeing here on planet wooden-head, but it will be a flying device with cameras and other instrumentation designed to give an overhead view of areas that might otherwise not be accessible to a ground-based rover.
NASA's helicopter mission will be incredibly interesting, as much because of the technological challenges this represents as due to the data obtained, if it works. And those technology hurdles are enormous.
For a start, the atmosphere of Mars is very, very thin, the wispy gases having a density to Earth's own atmosphere at an altitude of 100,000 feet. That's three times higher than any commercial passenger jet is able to fly and 50% higher than even the famous "high altitude" U2 spy plane operated at.
To lift a 1.8Kg mass (the helicopter itself) will require some serious capabilities.
Then there's the problem of powering this helicopter.
According to NASA's blurb, it will have lithium-ion batteries and solar cells for recharging... but even here on Earth, where the energy density of sunlight (1.3KW/m2) is twice the level received on Mars (0.5KW/m2, recharging the batteries of a drone from a tiny onboard solar array would take at least a full day. What's more, this meagre amount of energy must also keep the onboard systems warm during the bitterly cold Martian night.
Perhaps because of this limited power, the Martian helicopter has only a 90-second flight time, which is significantly less than the 20 minutes or so expected from a consumer-grade drone here on Earth.
However, perhaps the biggest problem that this drone will face is that of navigation.
Back on Earth, we have multiple constellations of GPS satellites screaming around the planet which enable any craft to pinpoint its location within just a few cm. On Mars however, no such luxury is available so the NASA heli will effectively have no way of telling exactly where it is -- other than perhaps some onboard optical processing. Because of this limitation, I expect that it would be very easy for the craft to become lost.
Then there's the issue of safe landings.
Although it has four widely spaced landing legs, the highly variable surface of Mars means it is not unlikely that a landing area may be uneven, sloped or very sandy. Any of these factors could adversely affect the craft's ability to return to ground safely and perform a subsequent takeoff. Again, the inability to use pin-point GPS and an existing high-resolution topographical map of the planet's surface make this a major risk factor in the success of the mission.
Finally, there's the design of the craft.
It is a coaxial helicopter which, all things considered, is probably the only option that was viable. A coaxial helicopter is relatively stable (hence their use in low-cost flying toys for kids) and can produce the maximum amount of lift for a given size. Compare the disk area of a coaxial helicopter with that of a four-rotor multirotor and you will see that the coaxial design is the most space-efficient, especially when you need to ensure that the thing will fold up and pack away for the long interplanetary journey.
However, coaxial helicopters of the design being used have one significant failing -- they are unable to cope with more than the slightest breeze -- as anyone who has attempted to fly such a craft here on Earth will confirm.
Attempting to get sufficient tilt on the rotor system in order to oppose more than the slightest breeze runs a very real risk that the two contra-rotating sets of blades will collide -- causing instant and catastrophic failure.
Now considering that the winds on Mars can be every bit as bad as the winds on Earth, NASA needs to hope that they get some calm days to fly this thing or it will quickly be blown away and unable to return.
It is however, the very complexity and apparent impossibility of this challenge that makes it so fascinating. NASA has blown us away before with the success of things such as its rovers, all of which have gone on to far-exceed their designed lifespan and deliver such a wealth of data from the surface of the Red Planet.
Can they do it again with this helicopter?
I sure hope so... but I have to say that I'm not as confident as I was about the rovers.
Let's hope they can do it.
I also trust they've issued the requisite NOTAMs with the Martian air-traffic control centre so as not to endanger any Martian airliners and so as to avoid the inevitable barrage of complaints from Martians who will claim they are being spied on by this craft.
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