Failure may tackle many types subsequent week when NASA’s next-gen rover, Perseverance, reaches the floor of the Pink Planet. Right here’s what must go proper—and the way issues may rapidly go sideways—when Perseverance tries to make its much-anticipated touchdown.
For NASA, the entry, descent, and touchdown (EDL) of Perseverance on Thursday, February 18 presents quite a few potential factors of failure. NASA has said that “a whole bunch of issues should go excellent” for the rover to outlive the seven minutes of terror. We will’t take a protected touchdown without any consideration: As NASA factors out, solely “about 40 % of the missions ever despatched to Mars—by any house company—have been profitable.” Which, yikes.
In a nutshell, Perseverance should transition from speeds reaching 12,500 miles per hour (20,000 km/hr) to a strolling tempo over the course of a number of minutes. What’s extra, it’ll should carry out this autonomously, because it takes practically 11 minutes for radio indicators to achieve Earth. To complicate issues, NASA is debuting two new applied sciences for the mission, each referring to the EDL section and each unproven.
All three phases—entry, descent, and touchdown—current their very own distinctive challenges.
The rover, nestled contained in the descent stage, will separate from the cruise stage, which, with its photo voltaic panels, radios, and gasoline tanks, will not be required. Subsequent, the spacecraft should orient itself such that its warmth defend is dealing with ahead, a activity made doable by small thrusters positioned on the backshell. Throughout atmospheric entry, the spacecraft’s warmth defend might want to endure temperatures reaching 2,370 levels Fahrenheit (1,300 levels Celsius). A structural failure at this stage could be catastrophic, ending the mission earlier than it has an opportunity to get began.
Certainly, earlier missions to the Pink Planet have failed proper on the Martian doorstep. In 1999, NASA’s Mars Local weather Orbiter entered into an orbit that was method too low, inflicting the spacecraft to fritter away within the ambiance. The failure was finally traced to a conversion error, through which imperial items of pound-seconds weren’t transformed to the usual metric Newton-seconds. Hate it when that occurs.
Ought to the descent stage survive atmospheric entry, it’ll nonetheless should take care of variably dense air pockets that would steer it off track. A guided entry can be carried out to keep away from this drawback, through which the descent stage will fireplace small thrusters to compensate.
The unfurling of the 70-foot-wide (21.5-meter) parachute is subsequent. Ought to the parachute unfurl correctly and never get tangled, the descent stage will abruptly decelerate to 1,000 miles per hour (1,600 km/h), which continues to be blazingly quick (keep in mind, Mars has a brilliant skinny ambiance). The deployment of this supersonic parachute will rely on an unproven new know-how referred to as Range Trigger, which is able to calculate the space to the touchdown spot and set off the parachute to deploy at simply the proper second. That is anticipated to occur roughly 240 seconds after atmospheric entry, when the descent stage is about 7 miles (11 km) above the floor. Perseverance will bid farewell to its warmth defend round 20 seconds after the parachute has unfurled, introducing one other potential level of failure.
It is a important stage—one with regrettable historic precedents. Throughout the failed landing of ESA’s Schiaparelli mission in 2016, the descent stage prematurely ejected the parachute and warmth defend, the results of a software program glitch. An onboard laptop thought it was only a few toes off the bottom, however in actuality the descent stage was someplace between 1.25 and a pair of.5 miles (2-4 km) above the floor. You’ll be able to think about what occurred subsequent. The doomed Schiaparelli lander was touring at round 185 miles per hour (300 km/h) when it smashed into the Martian regolith.
With the warmth defend gone, and with the rover now lastly uncovered to the Martian ambiance, one other new know-how will kick in, referred to as Terrain-Relative Navigation. The right execution of this device can be important, because the chosen touchdown spot, a crater, is kind of harmful.
“Jezero is 28 miles vast, however inside that expanse there are a whole lot of potential hazards the rover may encounter: hills, rock fields, dunes, the partitions of the crater itself, to call only a few,” Andrew Johnson, principal robotics methods engineer at NASA’s Jet Propulsion Laboratory, stated in a press release. “So, in case you land on a kind of hazards, it could possibly be catastrophic to the entire mission.”
Right here’s how NASA describes the brand new device, which ought to permit the touchdown craft to find out its place relative to the floor with a level of accuracy near round 130 toes (40 meters) or much less.
Terrain-Relative Navigation lets the rover make rather more correct estimates of its place relative to the bottom throughout descent. […] Utilizing photos from Mars orbiters, the mission crew creates a map of the touchdown website. The rover shops this map in its new laptop “mind,” designed particularly to assist Terrain-Relative Navigation. Descending on its parachute, the rover takes photos of the fast-approaching floor. To determine the place it’s headed, the rover rapidly compares the landmarks it sees within the photos to its onboard map. Armed with the data of the place it’s headed, the rover searches one other onboard map of protected touchdown zones to seek out the most secure place it may possibly attain. The rover can keep away from harmful floor as much as about 1,100 toes (335 meters) in diameter (in regards to the measurement of three soccer fields end-to-end), by diverting itself towards safer floor.
The parachute ought to gradual the descent stage right down to about 200 miles per hour (320 km/h), requiring one final step for decelerate: powered descent with eight tiny retro-rockets. After ditching the parachute, the rover, nonetheless hooked up to its backshell, will cruise towards the floor from an preliminary top of 6,900 toes (2,100 meters).
Some 12 seconds previous to landing, and on the very cheap velocity of 1.7 miles per hour (2.7 km/hr), it’ll be time for the skycrane maneuver. The backshell will decrease the rover utilizing three 66-foot-long (20-meter) cables, throughout which era the rover’s legs and wheels will transfer into their touchdown place. Perseverance, sensing an imminent touchdown, will let go of the cables, and the descent stage will zip off and crash—hopefully—distant.
A number of shifting components, together with some projectiles, clearly make this an awfully difficult dance. The warmth defend, parachute, and backshell all threat damaging or in any other case interfering with the touchdown and/or the efficiency of Perseverance.
Once more, historical past supplies one other instance of a mission failing at this level, particularly NASA’s Mars Polar Lander, which, just like the Mars Local weather Orbiter, died in 1999 (not an incredible 12 months for NASA). In accordance with NASA, the “most possible reason for the failure was the era of spurious indicators when the lander’s legs deployed throughout the descent,” which “falsely indicated that the spacecraft had touched down on Mars when in reality it was nonetheless descending,” inflicting the “principal engines [to] prematurely shut down,” ensuing within the lander falling to the Martian floor.
Ought to something go incorrect throughout the touchdown, Swati Mohan can be among the many first to know, as she’s the steerage, navigation, and management operations lead for the Mars 2020 mission. She’ll be at NASA mission management monitoring the progress and well being of the rover throughout the touchdown.
“Actual life can all the time throw you curve balls. So, we’ll be monitoring the whole lot throughout the cruise section, checking energy to the digital camera, ensuring the information is flowing as anticipated,” stated Mohan in a press release. “And as soon as we get that sign from the rover that claims, ‘I’ve landed and I’m on steady floor,’ then we are able to rejoice.”
The rover, although modeled on Curiosity, has many new options, together with an array of cameras and the power to see beneath the floor with ground-penetrating radar. The rover will land at Jezero crater, the place it’ll seek for indicators of historical life. If life as soon as existed on Mars, a spot like Jezero crater—a former lake and river delta—would’ve been a super place for microbes to hang around. Along with this necessary astrobiological work, Perseverance will even research Martian climate and geology, deploy a small helicopter named Ingenuity, and gather samples for a future mission.
NASA could have a stay stream of protection of the touchdown, which is scheduled for February 18 at 3:30 p.m. ET (12:30 p.m. PT). We’ll be watching and hoping for the finest.