Failure could take many forms next week when NASA’s next-generation rover, Perseverance, reaches the surface of the Red Planet. Here’s what should go right – and how things can go quickly sideways – when perseverance tries to make the long-awaited landing.
For NASA, the entry, descent and landing (EDL) of Persistence on Thursday, February 18, numerous possible points of failure are presented. NASA has said that “hundreds of things just have to go right” for the rover around the seven minutes of fright. We can not take a safe landing for granted: As NASA noted, only “about 40 percent of the missions ever sent to Mars – by any space agency – were successful.” What, yikes.
In a nutshell, endurance will have to switch from speeds of 20,000 km / h (20,000 km / h) to a running pace in a few minutes. What’s more, it will have to perform it autonomously, as it takes almost 11 minutes for radio signals to reach the earth. To complicate matters, NASA is launching two new technologies for the mission, both related to the EDL phase and both unproven.
All three phases – entry, descent and landing – present their own unique challenges.
G / O Media can get a commission
The rover, located in the downhill stage, will separate from the cruise stage, which with its solar panels, radios and fuel tanks are no longer needed. Next, the spacecraft must orient itself so that the heat shield looks forward, a task made possible by small thrusters located on the rear shell. During the atmosphere, the heat shield of the spacecraft must withstand the temperature of 2,370 degrees Fahrenheit (1,300 degrees Celsius). A structural failure at this stage would be catastrophic and end the mission before it gets a chance to get going.
On the contrary, previous missions to the Red Planet failed right before Mars’ threshold. In 1999, NASA’s Mars Climate Orbiter followed an orbit too much, causing the spacecraft to burn up in the atmosphere. The failure was finally found after a conversion error, in which imperial units of pound seconds were not converted to the standard metric Newton seconds. Hate it when it happens.
If the downward stage survives atmospheric access, it will still have to contend with volatile dense airbags that can send it off course. A guided entry will be made to avoid this problem, in which the downhill stage will fire small drivers to compensate.
The unfolding of the parachute 70 feet wide (21.5 meters) is as follows. If the parachute unfolds properly and does not become entangled, the descent stage will suddenly slow down to 1,000 miles per hour (1600 km / h), which is still fast (remember that Mars has a super-thin atmosphere). The use of this supersonic parachute will depend on an unproven new technology Series faster, which will calculate the distance to the landing site and cause the parachute to jump in at the right moment. This is expected to occur approximately 240 seconds after atmospheric access, when the descent stage is approximately 11 kilometers above the surface. Perseverance will say goodbye to his heat farewell about 20 seconds after the parachute unfolds, which in turn will provide a possible point of failure.
This is a critical stage – one with regrettable historical precedents. During the failed landing of the ESA’s Schiaparelli mission in 2016, the descent stage ejected the parachute and the heat shield prematurely, due to a software bug. A computer on board thought it was only a few feet off the ground, but in reality the descent stage was between 2-5 km above the surface. You can imagine what happened next. The doomed Schiaparelli lander was traveling at about 300 kilometers per hour (300 km / h) when it collided during the Mars War.
With the heat shield disappearing, and with the robber now finally being exposed to the Martian atmosphere, another new technology will turn on Terrain-relative navigation. The correct execution of this instrument is critical as the chosen landing site, a crater, is quite dangerous.
“Jezero is 45 km wide, but inside the firmament there are many potential dangers that the robber may encounter: hills, rocky fields, dunes, the walls of the crater itself, to name just a few,” said Andrew Johnson, chief robotic systems. engineer at NASA’s Jet Propulsion Laboratory, said in a Press release. “So if you run into any of the dangers, it could be catastrophic for the entire mission.”
Here’s how NASA describe the new instrument, which should enable the landing craft to determine its position with respect to the surface with an accuracy of about 40 meters or less.
Terrain-relative navigation allows the rover to estimate much more accurately its position relative to the ground during descent. […] Using images of Mars orbits, the mission team creates a map of the landing site. The rover stores this map in its new ‘brain’ of the computer, specifically designed to support terrain-related navigation. The rover takes off on its parachute and takes photos of the fast approaching surface. To find out where he is going, the rover quickly compares the landmarks he sees in the images with his map on board. Armed with the knowledge of where he is going, the rover searches for another map aboard safe landing zones to find the safest place he can reach. The robber can avoid dangerous ground to a diameter of about 1100 feet (about three foot fields to the end) by leading himself to a safer ground.
The parachute should slow down the descent to 320 km / h (320 km / h), which should be one last step for slower: powered descent with eight small retro rockets. After the parachute is thrown, the rover, which is still attached to its back shell, will sail from an initial height of 2,100 meters to the surface.
About twelve seconds before touch, and at a very reasonable speed of 2.7 km per hour (2.7 km / h), it’s time for the skycrane maneuver. The back shell lowers the stray beam using three 20-meter (20-meter) cables, during which the robber’s legs and wheels will move into their landing position. Perseverance, experiencing an impending landing, will loosen the cables, and the descent stage will descend and hopefully crash far away.
Many moving parts, including a number of projectiles, naturally make it an extraordinarily intricate dance. The heat shield, the parachute and the back cover can damage the landing and / or the performance of perseverance or otherwise interfere.
Once again, history provides another example of a mission that failed at this point, namely NASA’s Mars Polar Lander, which, like the Mars Climate Orbiter, died in 1999 (not a great year for NASA). According to NASA, the “most probable cause of the failure was the generation of false signals when the lander’s legs deployed during the descent,” which “falsely indicated that the spacecraft had touched Mars when in fact it was still descending engines. [to] prematurely turned off, ”which led to the lander falling to the Mars surface.
Should anything go wrong during the landing, Swati Mohan will be one of the first she knows guidance, navigation and control leads for the March 2020 broadcast. She will be at NASA’s mission control to monitor the rover’s progress and health during landing.
‘Real life can always throw you crooked balls. “So, we will monitor everything during the cruise phase, check the power to the camera and make sure that the data flows as expected,” Mohan said in a statement. Press release. “And as soon as we get the signal from the rover that says, ‘I landed and I’m on stable ground,’ then we can celebrate. “
The rover, although modeled on Curiosity, has many new features, including a variety of cameras and the ability to look underneath. the surface with ground penetrating radar. The robber will land at the Jezero crater, where he will look for signs of ancient life. Once life on Mars existed, a place like Jezero Crater – a former lake and river delta – would be the ideal place for microbes to hang out. In addition to this important astrobiological work, Perseverance will also study Mars weather and geology and use a small helicopter called Ingenuity, and collect monsters for a future mission.
NASA will have a live coverage of the landing, scheduled for Feb. 18 at 3:30 p.m. ET (12:30 p.m. PT). We will look and hope for the best.