Depiction of the Perseverance landing, with the rover still attached to backshell and retro-rockets engaged for powered descent. Illustration: NASA/JPL-Caltech
Failure could take on many forms next week when NASA’s next-gen rover, Perseverance, reaches the surface of the Red Planet. Here’s what needs to go right—and how things could quickly go sideways—when Perseverance tries to make its much-anticipated landing.
For NASA, the entry, descent, and landing (EDL) of Perseverance on Thursday, February 18 presents numerous potential points of failure. NASA has said that “hundreds of things have to go just right” for the rover to survive the seven minutes of terror. We can’t take a safe landing for granted: As NASA points out, only “about 40 percent of the missions ever sent to Mars—by any space agency—have been successful.” Which, yikes.
In a nutshell, Perseverance will have to transition from speeds reaching 12,500 miles per hour (20,000 km/hr) to a walking pace over the course of several minutes. What’s more, it’ll have to perform this autonomously, as it takes nearly 11 minutes for radio signals to reach Earth. To complicate matters, NASA is debuting two new technologies for the mission, both relating to the EDL phase and both unproven.
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All three phases—entry, descent, and landing—present their own unique challenges.
Graphic showing the various stages of the upcoming landing. Graphic: NASA/JPL-Caltech
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The rover, nestled inside the descent stage, will separate from the cruise stage, which, with its solar panels, radios, and fuel tanks, will no longer be required. Next, the spacecraft will have to orient itself such that its heat shield is facing forward, a task made possible by small thrusters located on the backshell. During atmospheric entry, the spacecraft’s heat shield will need to endure temperatures reaching 2,370 degrees Fahrenheit (1,300 degrees Celsius). A structural failure at this stage would be catastrophic, ending the mission before it has a chance to get started.
Indeed, previous missions to the Red Planet have failed right at the Martian doorstep. In 1999, NASA’s Mars Climate Orbiter entered into an orbit that was way too low, causing the spacecraft to burn up in the atmosphere. The failure was eventually traced to a conversion error, in which imperial units of pound-seconds were not converted to the standard metric Newton-seconds. Hate it when that happens.
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Should the descent stage survive atmospheric entry, it will still have to contend with variably dense air pockets that could steer it off course. A guided entry will be performed to avoid this problem, in which the descent stage will fire small thrusters to compensate.
Graphic comparing the size of the Curiosity rover’s landing ellipse (blue) with Perseverance’s landing ellipse (red). Graphic: NASA/JPL-Caltech
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The unfurling of the 70-foot-wide (21.5-meter) parachute is next. Should the parachute unfurl properly and not get tangled, the descent stage will abruptly decelerate to 1,000 miles per hour (1,600 km/h), which is still blazingly fast (remember, Mars has a super thin atmosphere). The deployment of this supersonic parachute will depend on an unproven new technology called Range Trigger, which will calculate the distance to the landing spot and trigger the parachute to deploy at just the right moment. This is expected to happen approximately 240 seconds after atmospheric entry, when the descent stage is about 7 miles (11 km) above the surface. Perseverance will bid farewell to its heat shield around 20 seconds after the parachute has unfurled, introducing another potential point of failure.
This is a critical stage—one with regrettable historical precedents. During the failed landing of ESA’s Schiaparelli mission in 2016, the descent stage prematurely ejected the parachute and heat shield, the result of a software glitch. An onboard computer thought it was just a few feet off the ground, but in reality the descent stage was somewhere between 1.25 and 2.5 miles (2-4 km) above the surface. You can imagine what happened next. The doomed Schiaparelli lander was traveling at around 185 miles per hour (300 km/h) when it smashed into the Martian regolith.
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Graphic showing how the terrain-relative navigation system will work.Graphic: NASA/JPL-Caltech
With the heat shield gone, and with the rover now finally exposed to the Martian atmosphere, another new technology will kick in, called Terrain-Relative Navigation. The proper execution of this tool will be critical, as the chosen landing spot, a crater, is quite dangerous.
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“Jezero is 28 miles wide, but within that expanse there are a lot of potential hazards the rover could encounter: hills, rock fields, dunes, the walls of the crater itself, to name just a few,” Andrew Johnson, principal robotics systems engineer at NASA’s Jet Propulsion Laboratory, said in a press release. “So, if you land on one of those hazards, it could be catastrophic to the whole mission.”
Here’s how NASA describes the new tool, which should allow the landing craft to determine its position relative to the surface with a degree of accuracy close to around 130 feet (40 meters) or less.
Terrain-Relative Navigation lets the rover make much more accurate estimates of its position relative to the ground during descent. […] Using images from Mars orbiters, the mission team creates a map of the landing site. The rover stores this map in its new computer “brain,” designed specifically to support Terrain-Relative Navigation. Descending on its parachute, the rover takes pictures of the fast-approaching surface. To figure out where it’s headed, the rover quickly compares the landmarks it sees in the images to its onboard map. Armed with the knowledge of where it’s headed, the rover searches another onboard map of safe landing zones to find the safest place it can reach. The rover can avoid dangerous ground up to about 1,100 feet (335 meters) in diameter (about the size of three football fields end-to-end), by diverting itself toward safer ground.
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The parachute should slow the descent stage down to about 200 miles per hour (320 km/h), requiring one last step for slow down: powered descent with eight tiny retro-rockets. After ditching the parachute, the rover, still attached to its backshell, will cruise toward the surface from an initial height of 6,900 feet (2,100 meters).
Depiction of the skycrane maneuver. Illustration: NASA/JPL-Caltech
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Some 12 seconds prior to touchdown, and at the very reasonable speed of 1.7 miles per hour (2.7 km/hr), it’ll be time for the skycrane maneuver. The backshell will lower the rover using three 66-foot-long (20-meter) cables, during which time the rover’s legs and wheels will move into their landing position. Perseverance, sensing an imminent landing, will let go of the cables, and the descent stage will zip off and crash—hopefully—far away.
Lots of moving parts, including some projectiles, obviously make this an extraordinarily complicated dance. The heat shield, parachute, and backshell all risk damaging or otherwise interfering with the landing and/or the performance of Perseverance.
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Again, history provides another example of a mission failing 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 spurious signals when the lander’s legs deployed during the descent,” which “falsely indicated that the spacecraft had touched down on Mars when in fact it was still descending,” causing the “main engines [to] prematurely shut down,” resulting in the lander falling to the Martian surface.
Should anything go wrong during the landing, Swati Mohan will be among the first to know, as she’s the guidance, navigation, and control operations lead for the Mars 2020 mission. She’ll be at NASA mission control tracking the progress and health of the rover during the landing.
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“Real life can always throw you curve balls. So, we’ll be monitoring everything during the cruise phase, checking power to the camera, making sure the data is flowing as expected,” said Mohan in a press release. “And once we get that signal from the rover that says, ‘I’ve landed and I’m on stable ground,’ then we can celebrate.”
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The rover, though modeled on Curiosity, has many new features, including an array of cameras and the ability to peer beneath the surface with ground-penetrating radar. The rover will land at Jezero crater, where it will search for signs of ancient life. If life once existed on Mars, a spot like Jezero crater—a former lake and river delta—would’ve been an ideal place for microbes to hang out. In addition to this important astrobiological work, Perseverance will also study Martian weather and geology, deploy a small helicopter named Ingenuity, and collect samples for a future mission.
NASA will have a live stream of coverage of the landing, 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 best.
TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.
Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.
Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.
The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.
The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.
It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.
Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.
Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.
Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.
Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.
Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.
The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”
VICTORIA – The British Columbia government is partnering with a bear welfare group to reduce the number of bears being euthanized in the province.
Nicholas Scapillati, executive director of Grizzly Bear Foundation, said Monday that it comes after months-long discussions with the province on how to protect bears, with the goal to give the animals a “better and second chance at life in the wild.”
Scapillati said what’s exciting about the project is that the government is open to working with outside experts and the public.
“So, they’ll be working through Indigenous knowledge and scientific understanding, bringing in the latest techniques and training expertise from leading experts,” he said in an interview.
B.C. government data show conservation officers destroyed 603 black bears and 23 grizzly bears in 2023, while 154 black bears were killed by officers in the first six months of this year.
Scapillati said the group will publish a report with recommendations by next spring, while an independent oversight committee will be set up to review all bear encounters with conservation officers to provide advice to the government.
Environment Minister George Heyman said in a statement that they are looking for new ways to ensure conservation officers “have the trust of the communities they serve,” and the panel will make recommendations to enhance officer training and improve policies.
Lesley Fox, with the wildlife protection group The Fur-Bearers, said they’ve been calling for such a committee for decades.
“This move demonstrates the government is listening,” said Fox. “I suspect, because of the impending election, their listening skills are potentially a little sharper than they normally are.”
Fox said the partnership came from “a place of long frustration” as provincial conservation officers kill more than 500 black bears every year on average, and the public is “no longer tolerating this kind of approach.”
“I think that the conservation officer service and the B.C. government are aware they need to change, and certainly the public has been asking for it,” said Fox.
Fox said there’s a lot of optimism about the new partnership, but, as with any government, there will likely be a lot of red tape to get through.
“I think speed is going to be important, whether or not the committee has the ability to make change and make change relatively quickly without having to study an issue to death, ” said Fox.
This report by The Canadian Press was first published Sept. 9, 2024.
The European Space Agency is fast-tracking a new mission called Ramses, which will fly to near-Earth asteroid 99942 Apophis and join the space rock in 2029 when it comes very close to our planet — closer even than the region where geosynchronous satellites sit.
Ramses is short for Rapid Apophis Mission for Space Safety and, as its name suggests, is the next phase in humanity’s efforts to learn more about near-Earth asteroids (NEOs) and how we might deflect them should one ever be discovered on a collision course with planet Earth.
In order to launch in time to rendezvous with Apophis in February 2029, scientists at the European Space Agency have been given permission to start planning Ramses even before the multinational space agency officially adopts the mission. The sanctioning and appropriation of funding for the Ramses mission will hopefully take place at ESA’s Ministerial Council meeting (involving representatives from each of ESA’s member states) in November of 2025. To arrive at Apophis in February 2029, launch would have to take place in April 2028, the agency says.
This is a big deal because large asteroids don’t come this close to Earth very often. It is thus scientifically precious that, on April 13, 2029, Apophis will pass within 19,794 miles (31,860 kilometers) of Earth. For comparison, geosynchronous orbit is 22,236 miles (35,786 km) above Earth’s surface. Such close fly-bys by asteroids hundreds of meters across (Apophis is about 1,230 feet, or 375 meters, across) only occur on average once every 5,000 to 10,000 years. Miss this one, and we’ve got a long time to wait for the next.
When Apophis was discovered in 2004, it was for a short time the most dangerous asteroid known, being classified as having the potential to impact with Earth possibly in 2029, 2036, or 2068. Should an asteroid of its size strike Earth, it could gouge out a crater several kilometers across and devastate a country with shock waves, flash heating and earth tremors. If it crashed down in the ocean, it could send a towering tsunami to devastate coastlines in multiple countries.
Over time, as our knowledge of Apophis’ orbit became more refined, however, the risk of impact greatly went down. Radar observations of the asteroid in March of 2021 reduced the uncertainty in Apophis’ orbit from hundreds of kilometers to just a few kilometers, finally removing any lingering worries about an impact — at least for the next 100 years. (Beyond 100 years, asteroid orbits can become too unpredictable to plot with any accuracy, but there’s currently no suggestion that an impact will occur after 100 years.) So, Earth is expected to be perfectly safe in 2029 when Apophis comes through. Still, scientists want to see how Apophis responds by coming so close to Earth and entering our planet’s gravitational field.
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“There is still so much we have yet to learn about asteroids but, until now, we have had to travel deep into the solar system to study them and perform experiments ourselves to interact with their surface,” said Patrick Michel, who is the Director of Research at CNRS at Observatoire de la Côte d’Azur in Nice, France, in a statement. “Nature is bringing one to us and conducting the experiment itself. All we need to do is watch as Apophis is stretched and squeezed by strong tidal forces that may trigger landslides and other disturbances and reveal new material from beneath the surface.”
The Goldstone radar’s imagery of asteroid 99942 Apophis as it made its closest approach to Earth, in March 2021. (Image credit: NASA/JPL–Caltech/NSF/AUI/GBO)
By arriving at Apophis before the asteroid’s close encounter with Earth, and sticking with it throughout the flyby and beyond, Ramses will be in prime position to conduct before-and-after surveys to see how Apophis reacts to Earth. By looking for disturbances Earth’s gravitational tidal forces trigger on the asteroid’s surface, Ramses will be able to learn about Apophis’ internal structure, density, porosity and composition, all of which are characteristics that we would need to first understand before considering how best to deflect a similar asteroid were one ever found to be on a collision course with our world.
Besides assisting in protecting Earth, learning about Apophis will give scientists further insights into how similar asteroids formed in the early solar system, and, in the process, how planets (including Earth) formed out of the same material.
One way we already know Earth will affect Apophis is by changing its orbit. Currently, Apophis is categorized as an Aten-type asteroid, which is what we call the class of near-Earth objects that have a shorter orbit around the sun than Earth does. Apophis currently gets as far as 0.92 astronomical units (137.6 million km, or 85.5 million miles) from the sun. However, our planet will give Apophis a gravitational nudge that will enlarge its orbit to 1.1 astronomical units (164.6 million km, or 102 million miles), such that its orbital period becomes longer than Earth’s.
It will then be classed as an Apollo-type asteroid.
Ramses won’t be alone in tracking Apophis. NASA has repurposed their OSIRIS-REx mission, which returned a sample from another near-Earth asteroid, 101955 Bennu, in 2023. However, the spacecraft, renamed OSIRIS-APEX (Apophis Explorer), won’t arrive at the asteroid until April 23, 2029, ten days after the close encounter with Earth. OSIRIS-APEX will initially perform a flyby of Apophis at a distance of about 2,500 miles (4,000 km) from the object, then return in June that year to settle into orbit around Apophis for an 18-month mission.
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Furthermore, the European Space Agency still plans on launching its Hera spacecraft in October 2024 to follow-up on the DART mission to the double asteroid Didymos and Dimorphos. DART impacted the latter in a test of kinetic impactor capabilities for potentially changing a hazardous asteroid’s orbit around our planet. Hera will survey the binary asteroid system and observe the crater made by DART’s sacrifice to gain a better understanding of Dimorphos’ structure and composition post-impact, so that we can place the results in context.
The more near-Earth asteroids like Dimorphos and Apophis that we study, the greater that context becomes. Perhaps, one day, the understanding that we have gained from these missions will indeed save our planet.
