NASA's Martian Helicopter...

...is ready for its first flight and, if successful, it will be a landmark moment in space exploration - the first time an aircraft has flown on an alien world.

It might not be a large vehicle weighing in at 4lbs, but the small vehicle will need all of its peak power output of 350w to get airborne and stay airborne in an environment that, due to its thin atmosphere, is ill-suited to airfoil lift.

The atmospheric pressure on the surface of Mars is 1% that of the earth's atmosphere at sea level, equivalent to the earth's atmosphere at an altitude of more than 100,000 thousand feet. To put that in perspective, the highest helicopter flight on earth reached an altitude of 40,000 feet, and though that was a manned flight in a heavy full-scale helicopter, it is still higher than any vertical take-off drone yet flown.

The wispy thin atmosphere of Mars is only one of the challenges Ingenuity faces. Some of which it is now encountering before even taking to the air. The nighttime temperature on the Martian surface drops to -90c (-130f)

Then there is the Martian wind.

Speeds can vary greatly, and exceed 100 km/h during storms, while dust devils have been known to spawn. These mini tornados are powerful enough to reach heights of 5kms, posing a potential hazard to Ingenuity when it is on the ground and again when in flight.

These conditions are challenging enough for a ground-based rover, yet it is into this alien environment that Nasa plans to deploy a drone helicopter, one which must be controlled remotely at a range of 275 million km.

The vehicle is a proof of concept model, aiming to show that controlled flight in the martian atmosphere is possible and, in the process, returning information to engineers at JPL that can be used in the design of future vehicles.

The prototype helicopter was developed in 2016, before being further improved and successfully tested in 2018. It was from this design that Ingenuity was built and, in 2019, flown inside the 25-foot space simulation chamber at NASA's Jet Propulsion Laboratory.

With the test successful and the vehicle working as intended, the 4lbs (1.8kg) craft was shipped to southern California and integrated onto the Perseverance rover. Launched into orbit atop an Atlas V-541 and into a mars transfer orbit in July 2020.

The launch, flight and landing went to plan, and the perseverance rover has begun its mission, part of which involved deployment of its fragile cargo.

With the helicopter deployed onto the surface and having passed all of its pre-fight tests, only weather checks concerning potentially excessive wind speeds now stand between Ingenuity and its first flight, scheduled for Sunday, April 11th.

update: Now scheduled for Wednesday, April 14th at the earliest after some anomolies were discovered in its pre-flight tests.

Information on the preparations and mission progress can be found at nasa's jpl website.