NASA’s Curiosity rover raised robotic arm with drill pointed skyward while exploring Vera Rubin Ridge at the base of Mount Sharp inside Gale Crater - backdropped by distant crater rim. This navcam camera mosaic was stitched from raw images taken on Sol 1833, Oct. 2, 2017 and colorized. Credit: NASA/JPL/Ken Kremer/kenkremer.com/Marco Di Lorenzo
Humans have been digging underground for millennia – on the Earth. It’s where we extract some of our most valuable resources that have moved society forward. For example, there wouldn’t have been a Bronze Age without tin and copper – both of which are primarily found under the ground. But when digging under the ground on celestial bodies, we’ve had a much rougher time. That is going to have to change if we ever hope to utilize the potential resources that are available under the surface. A paper from Dariusz Knez and Mitra Kahlilidermani of the University of Krakow looks at why it’s so hard to drill in space – and what we might do about it.
NASA’s Curiosity Mars rover captured this 360-degree panorama using its black-and-white navigation cameras, or Navcams, at a location where it collected a sample from a rock nicknamed “Sequoia.” The panorama was captured on Oct. 21 and 26, 2023. Credit: NASA/JPL-Caltech
Not to make anyone feel old, but it’s been over 11 years since NASA’s Curiosity Rover landed on Mars. The rover has now seen the sun rise on Mars over 4,000 times. During this time, the rover has driven almost 32 kilometers on Mars, making its way up the flanks of Mount Sharp while studying the ancient history of water on Mars.
The past 11 years have been quite the journey, but it hasn’t been all perfect. There have been a few computer glitches over the years, Curiosity’s wheels have gaping holes and gashes from driving over sharp rocks, and recently one of its camera filter wheels became stuck. But since the rover’s nominal mission was designed to last about two Earth years, Curiosity has proven to be a tough and enduring machine.
This is the Stimson sandstone formation in Gale Crater on Mars. This is where the Curiosity Rover drilled the Edinburgh hole and found enriched Carbon 12. Image Credit: NASA/Caltech-JPL/MSSS
Carbon is critical to life, as far as we know. So anytime we detect a strong carbon signature somewhere like Mars, it could indicate biological activity.
Does a strong carbon signal in Martian rocks indicate biological processes of some type?
Photos can’t do some places justice – nor can any level of sophisticated remote sensing. That seems to be the case for Gale Crater. Curiosity has been wandering around the crater for almost the last nine years. Scientists thought Gale crater was an old lakebed, and it was specifically chosen as a landing site to allow Curiosity to collect samples from such a lakebed. But new research from scientists at the University of Hong Kong shows that most likely, the samples Curiosity has been analyzing during its sojourn didn’t actually form in a lake.
Rocks can tell us a lot about a planet. On Earth, the study of geology has been around for hundreds of years and has resulted in such scientific findings as the theory of plate tectonics and the discovery of dinosaur fossils. Geology on Mars has not had as long and storied a history, but with the rovers that have landed on the planet in the last few decades, Martian geology has started to bloom. Curiosity, one of those rovers, has done a particularly good job at documenting the rock formations in its neighborhood of Gale crater. Now researchers led by a team at Imperial College London have published a paper using data from Curiosity that detail a set of ancient dunes on Mars that provide some insight into the planet’s former habitability.
The open source movement has been a fixture in the software and electronics worlds for over a decade now. Open source components serve as the basis from everything from 3D printed Iron Man figures to the Linux computer operating system. Now there’s a new open source project that ambitious creatives can undertake: building their very own Mars Curiosity Rover.
This low-angle self-portrait of NASA's Curiosity Mars rover shows the vehicle at the site from which it reached down to drill into a rock target called "Buckskin" on lower Mount Sharp. Credits: NASA/JPL-Caltech/MSSS
Since it landed on Mars in 2012, one of the main scientific objectives of the Curiosity rover has been finding evidence of past (or even present) life on the Red Planet. In 2014, the rover may have accomplished this very thing when it detected a tenfold increase in atmospheric methane in its vicinity and found traces of complex organic molecules in drill samples while poking around in the Gale Crater.
About a year ago, Curiosity struck pay dirt again when it found organic molecules in three-billion-year-old sedimentary rocks located near the surface of lower Mount Sharp. But last week, the Curiosity rover made an even more profound discovery when it detected the largest amount of methane ever measured on the surface of Mars – about 21 parts per billion units by volume (ppbv).
Special Guests:
This week we are excited to welcome Emily Lakdawalla, Senior Editor and Planetary Evangelist at The Planetary Society, back to the Weekly Space Hangout. On On May 14th, Emily’s new book, The Design and Engineering of Curiosity: How the Mars Rover Performs Its Job, will be released. It in, Emily describes the engineering that went into each instrument and piece of machinery incorporated into Curiosity’s systems. You can learn more about the book and Emily’s planned followup book on her blog here: http://www.planetary.org/blogs/emily-lakdawalla/2017/0831-book-update.html
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This self-portrait of NASA's Curiosity Mars rover shows the vehicle at the "Big Sky" site. Credit: NASA/JPL-Caltech/MSSS
Following is the final excerpt from my new book, “Incredible Stories From Space: A Behind-the-Scenes Look at the Missions Changing Our View of the Cosmos.” The book is an inside look at several current NASA robotic missions, and this excerpt is part 3 of 3 posted here on Universe Today, of Chapter 2, “Roving Mars with Curiosity.” You can read Part 1 here, and Part 2 here. The book is available in print or e-book (Kindle or Nook) Amazon and Barnes & Noble.
How to Drive a Mars Rover
How does Curiosity know where and how to drive across Mars’ surface? You might envision engineers at JPL using joysticks, similar to those used for remote control toys or video games. But unlike RC driving or gaming, the Mars rover drivers don’t have immediate visual inputs or a video screen to see where the rover is going. And just like at the landing, there is always a time delay of when a command is sent to the rover and when it is received on Mars.
“It’s not driving in a real-time interactive sense because of the time lag,” explained John Michael Morookian, who leads the team of rover drivers.
The actual job title of Morookian and his team are ‘Rover Planners,’ which precisely describes what they do. Instead of ‘driving’ the rovers per se; they plan out the route in advance, program specialized software, and upload the instructions to Curiosity.
“We use images taken by the rover of its surroundings,” said Morookian. “We have a set of stereo images from four black-and-white Navigation Cameras, along with images from the Hazcams (hazard avoidance cameras), supported by high-resolution color images from the MastCam that give us details about the nature of the terrain ahead and clues about types of rocks and minerals at the site. This helps identify structures that look interesting to the scientists.”
Using all available data, they can create a three-dimensional visualization of the terrain with specialized software called the Rover Sequencing and Visualization Program (RSVP).
“This is basically a Mars simulator and we put a simulated Curiosity in a panorama of the scene to visualize how the rover could traverse on its path,” Morookian explained. “We can also put on stereo glasses, which allow our eyes to see the scene in three dimensions as if we were there with the rover.
In virtual reality, the rover drivers can manipulate the scene and the rover to test every possibility of which routes are the best and what areas to avoid. There, they can make all the mistakes (get stuck in a dune, tip the rover, crash into a big rock, drive off a precipice) and perfect the driving sequence while the real rover remains safe on Mars.
“The scientists also review the images for features that are interesting and consult with the Rover Planners to help define a path. Then we compose the detailed commands that are necessary to get Curiosity from Point A to Point B along that path,” Morookian said. “”We can also incorporate the commands needed to give the rover direction to make contact with the site using its robotic arm.”
When Curiosity’s Navigation Cameras (Navcams) take black-and-white images and send them back to Earth each day, rover planners combine them with other rover data to create 3D terrain models. By adding a computerized 3D rover model to the terrain model, rover planners can understand better the rover’s position, as well as distances to, and scale of, features in the landscape. Credit: NASA/JPL-Caltech.
So, every night the rover is commanded to shut down for eight hours to recharge its batteries with the nuclear generator. But first Curiosity sends data to Earth, including pictures of the terrain and any science information. On Earth, the Rover Planners take that data, do their planning work, complete the software programing and beam the information back to Mars. Then Curiosity wakes up, downloads the instructions and sets to work. And the cycle repeats.
Curiosity also has an AutoNav feature which allows the rover to traverse areas the team hasn’t seen yet in images. So, it could go over the hill and down the other side to uncharted territory, with the AutoNav sensing potential hazards.
“We don’t use it too often because it is computationally expensive, meaning it takes much longer for the rover to operate in that mode,” Morookian said. “We often find it’s a better trade to just come in the next day, look at the images and drive as far as we can see.”
A view of the Space Flight Operations Facility at the Jet Propulsion Laboratory, where all the data going both to and from all planetary missions is sent and received via the Deep Space Network. Credit: Nancy Atkinson.
As Morookian showed me the various rooms used by rover planning teams at JPL, he explained how they need to operate over a number of different timescales.
“We not only have the daily route planning,” he said, “but also do long-range strategic planning using orbital imagery from the HiRISE camera on the Mars Reconnaissance Orbiter and choose paths based on features seen from orbit. Our team works strategically, looking many months out to define the best paths.”
Another process called Supra-Tactical looks out to just the next week. This involves science planners managing and refining the types of activities the rover will be doing in the short term. Also, since no one on the team lives on Mars Time anymore, on Fridays the Rover Planners work out the plans for several days.
“Since we don’t work weekends, Friday plans contain multiple sols of activities,” Morookian said. “Two parallel teams decide which days the rover will drive and which days it will do other activities, such as work with the robotic arm or other instruments.”
The data that comes down from the rover over the weekend is monitored, however, and if there is a problem, a team is called in to do a more detailed assessment. Morookian indicated they’ve had to engage the emergency weekend team several times, but so far there have been no serious problems. “It does keep us on our toes, however,” he said.
The rover features a number of reactive safety checks on the amount of overall tilt of the rover deck and the articulation of the suspension system of the wheels, so if the rover is going over an object that is too large, it will automatically stop.
Curiosity wasn’t built for speed. It was designed to travel up to 660 feet (200 meters) in a day, but it rarely travels that far in a Sol. By early 2016 the rover had driven a total of about 7.5 miles (12 km) across Mars’ surface.
This image shows a close-up of track marks left by the Curiosity rover. Holes in the rover’s wheels, seen here in this view, leave imprints in the tracks that can be used to help the rover drive more accurately. The imprint is Morse code for ‘JPL,’ and aids in tracking how far the rover has traveled. Credit: NASA/JPL-Caltech.
There are several ways to determine how far Curiosity has traveled, but the most accurate measurement is called ‘Visual Odometry.’ Curiosity has specialized holes in its wheels in the shape of Morse code letters, spelling out ‘JPL’ – a nod to the home of the rover’s science and engineering teams – across the Martian soil.
“Visual odometry works by comparing the most recent pair of stereo images collected roughly every meter over the drive,” said Morookian. “Individual features in the scene are matched and tracked to provide a measure of how the camera (and thus the rover) has translated and rotated in 3 dimensional space between the two images and it tells us in a very real sense how far Curiosity has gone.”
Careful inspection of the rover tracks can reveal the type of traction the wheels have and if they have slipped, for instance due to high slopes or sandy ground.
Unfortunately, Curiosity now has new holes in its wheels that aren’t supposed to be there.
Rover Problems
Morookian and Project Scientist Ashwin Vasavada both expressed relief and satisfaction that overall — this far into the mission — Curiosity is a fairly healthy rover. The entire science payload is currently operating at nearly full capability. But the engineering team keeps an eye on a few issues.
“Around sol 400, we realized the wheels were wearing faster than we expected,” Vasavada said.
The team operating the Curiosity Mars rover uses the Mars Hand Lens Imager (MAHLI) camera on the rover’s arm to check the condition of the wheels at routine intervals. This image of Curiosity’s left-middle and left-rear wheels is part of an inspection set taken on April 18, 2016, during the 1,315th sol of the rover’s work on Mars. Credit: NASA/JPL-Caltech/MSSS.
And the wear didn’t consist of just little holes; the team started to see punctures and nasty tears. Engineers realized the holes were being created by the hard, jagged rocks the rover was driving over during that time.
“We weren’t fully expecting the kind of ‘pointy’ rocks that were doing damage,” Vasavada said. “We also did some testing and saw how one wheel could push another wheel into a rock, making the damage worse. We now drive more carefully and don’t drive as long as we have in the past. We’ve been able to level off the damage to a more acceptable rate.”
Early in the mission, Curiosity’s computer went into ‘safe mode’ several times, as Curiosity’s software recognized a problem, and the response was to disallow further activity and phone home.
Specialized fault protection software runs throughout the modules and instruments, and when a problem occurs, the rover stops and sends data called ‘event records’ to Earth. The records include various categories of urgency, and in early 2015, the rover sent a message that essentially said, “This is very, very bad.” The drill on the rover’s arm had experienced a fluctuation in an electrical current – like a short circuit.
“Curiosity’s software has the ability to detect shorts, like the ground fault circuit interrupter you have in your bathroom,” Morookian explained, “except this one tells you ‘this is very, very bad’ instead of just giving you a yellow light.”
Since the team can’t go to Mars and repair a problem, everything is fixed either by sending software updates to the rover or by changing operational procedures.
Curiosity’s drill in the turret of tools at the end of the robotic arm positioned in contact with the rock surface for the first drilling of the mission on the 170th sol of Curiosity’s work on Mars (Jan. 27, 2013) in Yellowknife Bay. The picture was taken by the front Hazard-Avoidance Camera (Hazcam). Image credit: NASA/JPL-Caltech.
“We are just more careful now with how we use the drill,” Vasavada said, “and don’t drill with full force at the beginning, but slowly ramp up. It’s sort of like how we drive now, more gingerly but it still gets the job done. It hasn’t been a huge impact as of yet.”
A lighter touch on the drill also was necessary for the softer mudstones and sandstones the rover encountered. Morookian said there was concern the layered rocks might not hold up under the assault of the standard drilling protocol, and so they adjusted the technique to use the lowest ‘settings’ that still allows the drill to make sufficient progress into the rock.
But opportunities to use the drill are increasing as Curiosity begins its traverse up the mountain. The rover is traveling through what Vasavada calls a “target rich, very interesting area,” as the science team works to tie together the geological context of everything they are seeing in the images.
Finding Balance on Mars
While the diversion at Yellowknife Bay allowed the team to make some major discoveries, they felt pressure to get to Mt. Sharp, so “drove like hell for a year,” Vasavada said.
Now on the mountain, there is still the pressure to make the most of the mission, with the goal of making it through at least four different rock units – or layers — on Mt. Sharp. Each layer could be like a chapter in the book of Mars’ history.
A portion of a panorama from Curiosity’s Mastcam shows the rugged surface of ‘Naukluft Plateau’ plus part of the rim of Gale Crater, taken on April 4, 2016 or Sol 1301. Credit: NASA/JPL-Caltech/MSSS
“Exploring Mt. Sharp is fascinating,” Vasavada said, “and we’re trying to maintain a mix between really great discoveries, which – you hate to say — slows us down, and getting higher on the mountain. Looking closely at a rock in front of you means you’ll never be able to go over and look at that other interesting rock over there.”
Vasavada and Morookian both said it’s a challenge to preserve that balance every day — to find what’s called the ‘knee in the curve’ or ‘sweet spot’ of the perfect optimization between driving and stopping for science.
Then there’s the balance between stopping to do a full observation with all the instruments and doing ‘flyby science’ where less intense observations are made.
“We take the observations we can, and generate all the hypotheses we can in real time,” Vasavada said. “Even if we’re left with 100 open questions, we know we can answer the questions later as long as we know we’ve taken enough data.”
Curiosity’s primary target is not the summit, but instead a region about 1,330 feet (400 meters) up where geologists expect to find the boundary between rocks that saw a lot of water in their history, and those that didn’t. That boundary will provide insight into Mars’ transition from a wet planet to dry, filling in a key gap in the understanding of the planet’s history.
he Curiosity rover recorded this view of the Sun setting at the close of the mission’s 956th sol (April 15, 2015), from the rover’s location in Gale Crater. This was the first sunset observed in color by Curiosity. The image comes from the left-eye camera of the rover’s Mast Camera (Mastcam). Credit: NASA/JPL-Caltech/MSSS/Texas A&M University.
No one really knows how long Curiosity will last, or if it will surprise everyone like its predecessors Spirit and Opportunity. Having made it past the ‘prime mission’ of one year on Mars (two Earth years), and now in the extended mission, the one big variable is the RTG power source. While the available power will start to steadily decrease, both Vasavada and Morookian don’t expect that to be in an issue for at least four more Earth years, and with the right “nurturing,” power could last for a dozen years or more.
But they also know there’s no way to predict how long Curiosity will go, or what unexpected event might end the mission.
The Beast
Does Curiosity have a personality like the previous Mars rovers?
“Actually no, we don’t seem to anthropomorphize this rover like people did with Spirit and Opportunity,” Vasavada said. “We haven’t bonded emotionally with it. Sociologists have actually been studying this.” He shook his head with an amused smile.
Vasavada indicated it might have something to do with Curiosity’s size.
“I think of it as a giant beast,” he said straight-faced. “But not in a mean way at all.”
Curiosity appears to be photobombing Mount Sharp in this selfie image, a mosaic created from several MAHLI images. Credit: NASA/JPL-Caltech/MSSS/Edited by Jason Major.
What has come to come to characterize this mission, Vasavada said, is the complexity of it, in every dimension: the human component of getting 500 people to work and cooperate together while optimizing everyone’s talents; keeping the rover safe and healthy; and keeping ten instruments going every day, which are sometimes doing completely unrelated science tasks.
“Every day is our own little ‘seven minutes of terror,’ where so many things have to go right every single day,” Vasavada said. “There are a million potential issues and interactions, and you have to constantly be thinking about all the ways things can go wrong, because there are a million ways you can mess up. It’s an intricate dance, but fortunately we have a great team.”
Then he added with a smile, “This mission is exciting though, even if it’s a beast.”
“Incredible Stories From Space: A Behind-the-Scenes Look at the Missions Changing Our View of the Cosmos” is published by Page Street Publishing, a subsidiary of Macmillan.
Author Nancy Atkinson at JPL with a model of the Curiosity Rover.
NASA's MSL Curiosity. NASA is the only agency to successfully place a lander on Mars. This self portrait shows Curiosity doing its thing on Mars. Image: NASA/JPL-Caltech/MSSS
We may be living in the Golden Age of Mars Exploration. With multiple orbiters around Mars and two functioning rovers on the surface of the red planet, our knowledge of Mars is growing at an unprecedented rate. But it hasn’t always been this way. Getting a lander to Mars and safely onto the surface is a difficult challenge, and many landers sent to Mars have failed.
The joint ESA/Roscosmos Mars Express mission, and its Chiaparelli lander, is due at Mars in only 15 days. Now’s a good time to look at the challenges in getting a lander to Mars, and also to look back at the many failed attempts.
A model of the Schiaparelli lander. The lander is part of the ExoMars mission. By Pline – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=26837226
For now, NASA has the bragging rights as the only organization to successfully land probes on Mars. And they’ve done it several times. But they weren’t the first ones to try. The Soviet Union tried first.
The USSR sent several probes to Mars starting back in the 1960s. They made their first attempt in 1962, but that mission failed to launch. That failure illustrates the first challenge in getting a craft to land on Mars: rocketry. We’re a lot better at rocketry than we were back in the 1960’s, but mishaps still happen.
Then in 1971, the Soviets sent a pair of probes to Mars called Mars 2 and Mars 3. They were both orbiters with detachable landers destined for the Martian surface. The fate of Mars 2 and Mars 3 provides other illustrative examples of the challenges in getting to Mars.
Mars 2 separated from its orbiter successfully, but crashed into the surface and was destroyed. The crash was likely caused by its angle of descent, which was too steep. This interrupted the descent sequence, which meant the parachute failed to deploy. So Mars 2 has the dubious distinction of being the first man-made object to reach Mars.
Mars 3 was exactly the same as Mars 2. The Soviets liked to do missions in pairs back then, for redundancy. Mars 3 separated from its orbiter and headed for the Martian surface, and through a combination of aerodynamic breaking, rockets, and parachutes, it became the first craft to make a soft landing on Mars. So it was a success, sort of.
A model of the Mars 3 lander with its petals open after landing. By NASA – http://nssdc.gsfc.nasa.gov/image/spacecraft/mars3_lander_vsm.jpg, Public Domain, https://commons.wikimedia.org/w/index.php?curid=14634254
But after only 14.5 seconds of data transmission, it went quiet and was never heard from again. The cause was likely an intense dust storm. In an odd turn of events, NASA’s Mariner 9 orbiter reached Mars only days before Mars 2 and 3, becoming the first spacecraft to orbit another planet. It captured images of the planet-concealing dust storms, above which only the volcanic Olympus Mons could be seen. These images provided an explanation for the failure of Mars 3.
This image from the Mariner 9 orbiter shows Olympus Mons above the dust storms that concealed much of the planet when it arrived at Mars in 1971. Image: NASA
In 1973, the Soviets tried again. They sent four craft to Mars, two of which were landers, named Mars 6 and Mars 7. Mars 6 failed on impact, but Mars 7’s fate was perhaps a little more tragic. It missed Mars completely, by about 1300 km, and is in a helicentric orbit to this day. In our day and age, we just assume that our spacecraft will go where we want them to, but Mars 7 shows us that it can all go wrong. After all, Mars is a moving target.
In the 1970s, NASA was fresh off the success of their Apollo Program, and were setting their sites on Mars. They developed the Viking program which saw 2 landers, Viking 1 and Viking 2, sent to Mars. Both of them were probe/lander configurations, and both landers landed successfully on the surface of Mars. The Vikings sent back beautiful pictures of Mars that caused excitement around the world.
The Viking 2 lander captured this image of itself on the Martian surface. By NASA – NASA website; description,[1] high resolution image.[2], Public Domain, https://commons.wikimedia.org/w/index.php?curid=17624
In 1997, NASA’s Martian Pathfinder made it to Mars and landed successfully. Pathfinder itself was stationary, but it brought a little rover called Sojourner with it. Sojourner explored the immediate landing area around Pathfinder. Sojourner became the first rover to operate on another planet.
Pathfinder was able to send back over 16,000 images of Mars, along with its scientific data. It was also a proof of concept mission for technologies such as automated obstacle avoidance and airbag mediated touchdown. Pathfinder helped lay the groundwork for the Mars Exploration Rover Mission. That means Spirit and Opportunity.
An artist’s conception of Spirit/Opportunity working on Mars. By NASA/JPL/Cornell University, Maas Digital LLC – http://photojournal.jpl.nasa.gov/catalog/PIA04413 (image link), Public Domain, https://commons.wikimedia.org/w/index.php?curid=565283
But after Pathfinder, and before Spirit and Opportunity, came a time of failure for Martian landing attempts. Everybody took part in the failure, it seems, with Russia, Japan, the USA, and the European Space Agency all experiencing bitter failure. Rocket failures, engineering errors, and other terminal errors all contributed to the failure.
Japan’s Nozomi orbiter ran out of fuel before ever reaching Mars. NASA’s Mars Polar Lander failed its landing attempt. NASA’s Deep Space 2, part of the Polar Lander mission, failed its parachute-less landing and was never heard from. The ESA’s Beagle 2 lander made it to the surface, but two of its solar panels failed to deploy, ending its mission. Russian joined in the failure again, with its Phobos-Grunt mission, which was actually headed for the Martian moon Phobos, to retrieve a sample and send it back to Earth.
In one infamous failure, engineers mixed up the use of English units with Metric units, causing NASA’s Mars Climate Orbiter to burn up on entry. These failures show us that failure is not rare. It’s difficult and challenging to get to the surface of Mars.
After this period of failure, NASA’s Spirit and Opportunity rovers were both unprecedented successes. They landed on the Martian surface in January 2004. Both exceeded their planned mission length of three months, and Opportunity is still going strong now.
So where does that leave us now? NASA is the only one to have successfully landed a rover on Mars and have the rover complete its mission. But the ESA and Russia are determined to get there.
The Schiaparelli lander, as part of the ExoMars mission, is primarily a proof of technology mission. In fact, its full name is the Schiaparelli EDM lander, meaning Entry, Descent, and Landing Demonstrator Module.
It will have some small science capacity, but is really designed to demonstrate the ability to enter the Martian atmosphere, descend safely, and finally, to land on the surface. In fact, it has no solar panels or other power source, and will only carry enough battery power to survive for 2-8 days.
Schiaparelli faces the same challenges as other craft destined for Mars. Once launched successfully, which it was, it had to navigate its way to Mars. That took about 6 months, and since ExoMars is only 15 days away from arrival at Mars, it looks like it has successfully made its way their. But perhaps the trickiest part comes next: atmospheric entry.
Schiaparelli is like most Martian craft. It will make a ballistic entry into the Martian atmosphere, and this has to be done right. There is no room for error. The angle of entry is the key here. If the angle is too steep, Schiaparelli may overheat and burn up on entry. On the other hand, if the angle is too shallow, it could hit the atmosphere and bounce right back into space. There’ll be no second chance.
The entry and descent sequence is all pre-programmed. It will either work or it won’t. It would take way too long to send any commands to Schiaparelli when it is entering and descending to Mars.
If the entry is successful, the landing comes next. The exact landing location is imprecise, because of wind speed, turbulence, and other factors. Like other craft sent to Mars, Schiaparelli’s landing site is defined as an ellipse.
Schiaparelli will land somewhere in this defined ellipse on the surface of Mars. Image: IRSPS/TAS-I
The lander will be travelling at over 21,000 km/h when it reaches Mars, and will have only 6 or 7 minutes to descend. At that speed, Schiaparelli will have to withstand extreme heating for 2 or 3 minutes. It’s heat shield will protect it, and will reach temperatures of several thousand degrees Celsius.
It will decelerate rapidly, and at about 10km altitude, it will have slowed to approximately 1700 km/h. At that point, a parachute will deploy, which will further slow the craft. After the parachute slows its descent, the heat shield will be jettisoned.
Schiaparelli’s Descent and Landing Sequence. Image: ESA/ATG medialab. Click here for larger image.
On Earth, a parachute would be enough to slow a descending craft. But with Mars’ less dense atmosphere, rockets are needed for the final descent. An onboard radar will monitor Schiaparelli’s altitude as it approaches the surface, and rockets will fire to slow it to a few meters per second in preparation for landing.
In the final moments, the rockets will stop firing, and a short free-fall will signal Schiaparelli’s arrival on Mars. If all goes according to plan, of course.
We won’t have much longer to wait. Soon we’ll know if the ESA and Russia will join NASA as the only agencies to successfully land a craft on Mars. Or, if they’ll add to the long list of failed attempts.
![The Viking 2 lander captured this image of itself on the Martian surface. By NASA - NASA website; description,[1] high resolution image.[2], Public Domain, https://commons.wikimedia.org/w/index.php?curid=17624](https://www.universetoday.com/wp-content/uploads/2016/10/608px-Viking2lander1.jpg)
