This week, we saw the first controlled, powered-flight on another planet. Really, anywhere beyond Earth. Ingenuity as it is called, is a helicopter/drone currently on Mars.
Ingenuity hitched a ride with NASA's latest rover Perseverance. It was attached underneath for the seven-month journey to Mars. Slowly, just like a parent giving their child more freedom, Ingenuity was put on the Martian surface and exposed to the Martian atmosphere.
Surviving by itself was no walk in the park. The average temperature on Mars is around minus 60 degrees. In some places, it can warm all the way up to 20 degrees, but it can also dip down below minus 150 degrees. That is a huge range, and at those cold temperatures, most electronics stop working.
The Martian air is also very different to that here on Earth. Not only is it mostly carbon dioxide, but there is not a lot of it. The density is about 1.5 per cent of the air density here on Earth. Gravity is also less on Mars - about one-third that of Earth. So if you weigh 100 kilograms on Earth, you way about 34 kilograms on Mars.
The conditions to fly on Mars are very different than Earth. In reality, it would be like flying a helicopter at 35 km high on Earth.
Commercial aeroplanes on Earth fly at about 8 to 10km high. The SR-71, the specialised US military plane, flew at about 27km. Even the record setting flights on Earth are in the 37km range - most of which involved rockets and special equipment.
Ingenuity had to operate in an environment that is the most extreme of flying conditions here on Earth. And it had to do it, while operating remotely over 290 million kilometres from Earth.
The huge distance meant that there was a massive communication delay - a lag. It had to operate with a pre-programmed flight and if something went wrong, they would not be able to fix it.
However, Ingenuity wasn't the first flight on another planet. That title goes to the Vega program which were high-altitude balloons flown by the Soviet Union on Venus. Flown at an altitude of about 50km, Venus has a very different atmosphere to Mars. The atmosphere is very thick, so flying at 50km on Venus is only like 5km on Earth.
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The Vega missions were also not a powered, controlled flight. Just as on Earth, balloons proceeded the Wright brothers before they made their famous flight. And while Ingenuity only flew 3 metres high and for 40 seconds, the Wright brothers' first flight only lasted 12 seconds and went 36 metres.
So seeing this helicopter, which weighs only 1.8kg go 3 metres up for 40 seconds was a huge feat. The blades, which had to be much longer than it would be here on Earth, had to spin at 2400 rpm while only weighing about the same as an A4 sheet of paper.
It has already had its second flight, and its third flight is already scheduled. They are going higher, further, and longer each time.
Ingenuity has really lived up to its name - a type of craft we had never seen before. In another way, from the perspective of Mars, it really was a UFO flying on Mars.
- Brad Tucker is an astrophysicist and cosmologist at Mount Stromlo Observatory, and the National Centre for the Public Awareness of Science at ANU
