By Chris Stonor
Mars helicopter, Mars drone, what’s semantics amongst friends as NASA prepares Ingenuity’s maiden flight over the red planet, for no earlier than April 8th. Yet, before the 1.8-kilogram rotorcraft can attempt its first flight both it and the team must meet a series of daunting milestones, reports a NASA press release.
Ingenuity remains attached to the belly of NASA’s Perseverance rover, which touched down on Mars on February 18th. This week the rover deployed the guitar case-shaped graphite composite debris shield that protected Ingenuity during landing. The rover currently is in transit to the “airfield” where Ingenuity will attempt its maiden flight. Once deployed, the craft will have 30 Martian days, or sols, (31 Earth days) to conduct its test flight campaign.
Lori Glaze, Director of the Planetary Science Division at NASA HQ, comments, “We want to learn about the potential Ingenuity has for the future of science research. This is the first powered flight on another world and, if successful, could further expand our horizons and broaden the scope of what is possible with Mars exploration.”
Ingenuity’s Maiden Flight Area
The press release explains, “Flying in a controlled manner on Mars is far more difficult than flying on Earth. The Red Planet has significant gravity (about one-third that of Earth’s), but its atmosphere is just 1% as dense as Earth’s at the surface. During Martian daytime, the planet’s surface receives only about half the amount of solar energy that reaches Earth during its daytime, and nighttime temperatures can drop as low as minus 130 degrees Fahrenheit (minus 90 degrees Celsius), which can freeze and crack unprotected electrical components.”
It continues, “To fit within the available accommodations provided by the Perseverance rover, Ingenuity must be small. To fly in the Mars environment, it must be lightweight. To survive the frigid Martian nights, it must have enough energy to power internal heaters. The system – from the performance of its rotors in rarified air to its solar panels, electrical heaters, and other components – has been tested and retested in the vacuum chambers and test labs of NASA’s Jet Propulsion Laboratory in Southern California.”
Bob Balaram, Ingenuity’s chief engineer at JPL, says, “Every step we have taken since this journey began six years ago has been uncharted territory in the history of aircraft and while getting deployed to the surface will be a big challenge, surviving that first night on Mars alone, without the rover protecting it and keeping it powered, will be an even bigger one.”
Before the craft takes its first flight on Mars, it must be squarely in the middle of its airfield, a 10-by-10-metre patch of Martian real estate chosen for its flatness and lack of obstructions.
Farah Alibay, Ingenuity integration lead for the Perseverance rover, comments, “This type of deployment has never been done before. Once we start there is no turning back. All activities are closely coordinated, irreversible, and dependent on each other. If there is even a hint that something isn’t going as expected, we may decide to hold off for a sol or more until we have a better idea what is going on.”
Flight Zone – Another Viewpoint
The press release explains the deployment process will take about six sols (six days, four hours on Earth). On the first sol, the team on Earth will activate a bolt-breaking device, releasing a locking mechanism that helped hold the craft firmly against the rover’s belly during launch and Mars landing. The following sol, they will fire a cable-cutting pyrotechnic device, enabling the mechanised arm that holds Ingenuity to begin rotating it out of its horizontal position. This is also when the rotorcraft will extend two of its four landing legs.
During the third sol of the deployment sequence, a small electric motor will finish rotating Ingenuity until it latches, bringing the craft completely vertical. During the fourth sol, the final two landing legs will snap into position. On each of those four sols, the Wide Angle Topographic Sensor for Operations and eNgineering (WATSON) imager will take confirmation shots of Ingenuity as it incrementally unfolds into its flight configuration. In its final position, the craft will hang suspended at about 5 inches (13 centimeters) over the Martian surface. At that point, only a single bolt and a couple dozen tiny electrical contacts will connect it to Perseverance. On the fifth sol of deployment, the team will use the final opportunity to utilise Perseverance as a power source and charge Ingenuity’s six battery cells.
Balaram continues, “Once we cut the cord with Perseverance and drop those final 5 inches to the surface, we want to have our big friend drive away as quickly as possible so we can get the Sun’s rays on our solar panel and begin recharging our batteries.”
The press release goes on to say that on the sixth and final scheduled sol of this deployment phase, the team will need to confirm three things: that Ingenuity’s four legs are firmly on the surface of Jezero Crater, that the rover did, indeed, drive about 16 feet (about 5 meters) away, and that both craft and rover are communicating via their onboard radios. This milestone also initiates the 30-sol clock during which time all preflight checks and flight tests must take place.
MiMi Aung, project manager for Ingenuity at JPL, points out, “Ingenuity is an experimental engineering flight test. There are no science instruments on-board and no goals to obtain scientific information. We are confident that all the engineering data we want to obtain both on the surface of Mars and aloft can be done within this 30-sol window.”
The press release continues, “If the team misses or has questions about an important pre-flight milestone, they may take one or more sols to better understand the issue. If the ‘drone’ survives the first night of the sequence period on the Mars surface, however, the team will spend the next several sols doing everything possible to ensure a successful flight, including wiggling the rotor blades and verifying the performance of the inertial measurement unit, as well as testing the entire rotor system during a spin-up to 2,537 rpm while the landing gear remain firmly on the surface.
“Once the team is ready to attempt the first flight, Perseverance will receive and relay to Ingenuity the final flight instructions from JPL mission controllers. Several factors will determine the precise time for the flight, including modeling of local wind patterns plus measurements taken by the Mars Environmental Dynamics Analyzer (MEDA) aboard Perseverance. Ingenuity will run its rotors to 2,537 rpm and, if all final self-checks look good, lift off. After climbing at a rate of about 3 feet per second (1 meter per second), the craft will hover at 10 feet (3 meters) above the surface for up to 30 seconds. Then, Ingenuity will descend and touch back down on the Martian surface.”
Perseverance Rover Eyes the Red Planet’s Surface
Several hours after the first flight has occurred, Perseverance will downlink Ingenuity’s first set of engineering data and, possibly, images and video from the rover’s Navigation Cameras and Mastcam-Z. From the data downlinked that first evening after the flight, the team expects to be able to determine if their first attempt to fly at Mars was a success.
On the following sol, all the remaining engineering data collected during the flight, as well as some low-resolution black-and-white imagery from the helicopter’s own Navigation Camera, could be downlinked to JPL. The third sol of this phase, the two images taken by the craft’s high-resolution color camera should arrive. The team will use all information available to determine when and how to move forward with their next test.
Aung says, “Mars is hard. Our plan is to work whatever the Red Planet throws at us the very same way we handled every challenge we’ve faced over the past six years – together, with tenacity and a lot of hard work, and a little Ingenuity.”
For more information
(News Source: https://mars.nasa.gov)