For the first time in history, a cunning helicopter will conquer the skies of another planet. To make sure the rover is ready to debut on the Red Planet, NASA engineers in Pasadena, California, developed prototypes of “Ingenuity” (the name of the rover). They put one prototype through rigorous testing to see if it could withstand the cold temperatures and vibrations associated with landing. Another prototype was designed specifically for flight testing in a 25-foot-diameter chamber designed by JPL to simulate a vacuum. In this article, Popular Mechanics spoke with Bob Balaram and Howard Phaser Grip to find out what technical features make the first Mars craft truly groundbreaking.
Everything is almost ready for the show. When the mysterious extraterrestrial helicopter detaches from the rover to conduct a series of 5 test flights lasting from 30 to 90 seconds, it will have 30 Martian days, and each Martian day consists of 24 hours, 39 minutes and 35 seconds. Nearly all of the Mars Flight’s most ambitious jumps will be choreographed by Ingenuity itself, and will range in height from a one-story building to 1,000 feet.
While Ingenuity is a demonstration technology, that is, its sole purpose is to safely take off in the Martian sky, a successful flight could change our approach to exploring the solar system.
Ingenuity’s two-foot blades are specially designed for the Martian atmosphere, which is one percent of Earth’s density. “When rotating, the blades tend to swing up and down, which interferes with control,” says the renowned mechanic. Bob Balaram– on Earth this movement is extinguished, but on Mars, in a rarefied atmosphere, this does not happen. ”
Howard Phaser Grip, a technology researcher also at JPL, compares erratic movement to cycling loaded with heavy grocery bags hanging over the handlebars. To counteract vibrations and make flight smooth, the blades, which have a foam core and carbon coating, were designed to be lightweight but extremely stiff.
A distinctive feature of the rotor system is its size, which is huge in comparison with the entire rotorcraft.
“This is one of the consequences of being so low,” says Grip. “You just need a big rotor – as big as it can fit.” And he has to spin the blades quickly – at 2800 rpm, or more than 10 times faster than the blades spin on Earth, but not too fast. The speed of sound is lower on Mars – about 540 miles per hour compared to 760 miles per hour on Earth – and the rover should be no faster than that speed.
“When you reach transonic speeds, the drag at the tip of the blades becomes very high,” says Grip. “At this point, the energy required to move the rotors leads to an explosion.”
Inventiveness has upper and lower rotors. Each assembly contains a traction motor, stepper links, and three servos that work together to steer the rover. Four additional counterweights, two for each rotor, create “restoring force on the blades under centrifugal loads … lowering torque requirements” “Ingenuity” (quoted from NASA research).
The engineers settled on a coaxial rotor configuration rather than a tail rotor or quadcopter design, as this configuration is incredibly compact; this means that it can easily fit into the rover, but it does not mean that quadro- and hexacopters will remain out of future missions.
“We are investigating different vehicle designs that would allow us to move further, faster and carry more payload,” says Grip.
The four carbon fiber and epoxy resin mounts are very lightweight and are attached to the landing platform with deformable aluminum hinges that help dampen the force of impact and prevent the rotorcraft from bouncing.
“We want to land with confidence, without even bouncing a lot,” says Grip. The Ingenuity test team tested the supports on analogs of Martian surfaces, including rocks and sand.
“Advanced batteries with a metamorphic four-junction solar cell that help Ingenuity tune into the Martian spectrum,” Balaram says. “This means they are optimized to absorb most of the light that reaches Mars.”
Lithium Ion Batteries
“The solar panels will charge six Sony Ingenuity lithium-ion batteries. If necessary, the battery can generate about 500 watts, says Balaram. Depending on the season and the size of the mission, it takes approximately one Martian day to charge the batteries. ”
There is no magnetic field on Mars, so compasses and GPS systems are useless. Instead, the rover uses a black-and-white navigation camera that captures images of the surface during flight. “In this camera frame, we are detecting the features of the ground that we are tracking,” says Grip. – It helps to see how we are moving relative to the Martian soil. Sony’s 13-megapixel Return-to-Earth color camera will take images of the horizon and send them back to Earth for us to view. “
These images, combined with lidar altimeter observations and inertia measurements, will help Ingenuity make decisions about where to fly and ultimately where to land.
“With these three sensors, we can always track what the Mars is doing and where it is,” says Grip.
Fuselage electronics box
The fuselage contains an upper sensor assembly, attached to the mast of the rover, which in turn includes an inclinometer, an inertial measuring unit and protection elements for the helicopter electronics, which minimize vibration in flight. The lower unit of the sensor contains an altimeter, navigation cameras and a second inertial measuring unit.
One of the most serious problems that a spacecraft will face is the problem of heat. The average temperature on the surface of Mars is approximately minus 64 degrees Fahrenheit. To keep Ingenuity’s sensitive electronic equipment warm enough to operate, Balaram and his team devised several clever methods.