“The mission has 314 million miles of interplanetary space and seven minutes of terror to safely reach the surface of Mars,” said Lori Glaze, director of NASA’s planetary science division, in a statement. “When we see the landscape in Jezero Crater for the first time and we really begin to realize the scientific reward before us, the fun really begins.”
Perseverance and the Ingenuity helicopter are housed within a protective aerosol pod. The descent stage that will help land the rover is also found in this aeroshell, which is connected to the cruise stage, or the mission spacecraft.
The cruise stage is disk shaped and powered by solar energy. It will travel over 300 million miles to reach Mars.
While sailing to Mars, engineers on Earth will tell the spacecraft when to execute correction maneuvers to keep it on the right path to Mars, as well as its landing target. The ground team will also perform controls on the instruments and subsystems on the spacecraft.
Approximately 45 days before landing on Mars, the spacecraft will enter the approach phase, with more correction maneuvers to its trajectory.
During what is to be expected a smooth journey to Mars, the Perseverance teams will prepare and train for when the rover lands on Mars. The scientific team will prepare the instructions it wants to send to the rover while using its instruments on Mars.
Rover drivers will also work with a model of the rover on Earth to prepare for the Perseverance journey across the Martian surface.
This includes using a Earth Perseverance twin to test the hardware, steer it through Mars Yard at NASA’s Jet Propulsion Laboratory in Pasadena, California, and make sure the automatic navigation algorithms work, he said. Heather Justice, leader of the downlink robotic operation and one of the rover drivers at JPL.
‘Seven minutes of terror’
The one-way light time it takes for radio signals to travel from Earth to Mars is approximately 10.5 minutes, which means that the seven minutes it takes for the spacecraft to land on Mars will occur without any help or intervention from NASA on Earth.
NASA team members refer to this as the “seven minutes of terror.” They tell the spacecraft when to start EDL (entry, descent, and landing), and the spacecraft takes over there.
The spacecraft hits the upper part of the Martian atmosphere moving at 12,000 miles per hour and has to slow down to zero miles per hour seven minutes later when the rover gently lands on the surface.
About 10 minutes before entering the thin Martian atmosphere, the cruise stage fades and the spacecraft prepares for a guided entry, where small thrusters in the hull help adjust its angle.
The spacecraft’s heat shield will withstand a maximum heating of 2,370 degrees Fahrenheit 75 seconds after entering the atmosphere.
Perseverance points to an ancient lake bed and a 28-mile-wide river delta, the most challenging site yet for a NASA spacecraft landing on Mars. Rather than being flat and smooth, the small landing site is filled with sand dunes, cliffs, rocks, and small craters.
The spacecraft has two updates, called Range Trigger and Terrain-Relative Navigation, to navigate this difficult and dangerous site.
Range Trigger will tell the 70.5-foot-wide parachute when to deploy based on the spacecraft’s position 240 seconds after entering the atmosphere. After the parachute deploys, the heat shield will come off.
Terrain-related navigation acts as a second brain for the rover, using cameras to take pictures of the ground as it rapidly approaches and determines the safest place to land. According to NASA, it can change the landing site up to 2,000 feet.
The rear cover and the parachute separate after the heat shield is discarded when the spacecraft is 1.3 miles above the Martian surface. Mars’ landing engines, which include eight retro-rockets, will fire to slow the descent from 190 miles per hour to about 1.7 miles per hour.
Then, the famous celestial crane maneuver that landed on the Curiosity rover will occur. The nylon cords will lower the rover 25 feet below the descent stage. After the rover lands on the Martian surface, the cables will come off and the descent stage will fly and land at a safe distance.
On the surface of Mars
Once the rover has landed, the two-year Perseverance mission will begin and go through a “check-in” period to make sure it’s ready.
The rover will deploy its mast and antenna, take a picture of its landing staff, perform a “status check” on its instruments, test motion and “flex” its arm and perform a short test drive. Perseverance will also release her tummy, which provided a safe haven for the Ingenio helicopter stored there during the cruise and landing.
The rover will also find a nice flat surface to drop the Ingenuity helicopter into, so it has a place to use as a heliport for its possible five test flights over a period of 30 days. This will occur within the first 50 to 90 soles, or Martian days, of the mission.
Once Ingenuity settles to the surface, Perseverance will drive to a safe location at a distance and use their cameras to observe Ingenuity’s flight.
After those flights, Perseverance will begin searching for evidence of ancient life, studying the climate and geology of Mars, and collecting samples that will eventually be returned to Earth through future planned missions.
.
