NASA's Curiosity rover sniffed out an unexpected seasonal variation to the oxygen on Mars, according to new research. From a report: Since it landed in Gale Crater in 2012, the Curiosity rover has been studying the Martian surface beneath its wheels to learn more about the planet's history. But Curiosity also stuck its nose in the air for a big sniff to understand the Martian atmosphere. So far, this sniffing has resulted in some findings that scientists are still trying to understand. Earlier this year, the rover's tunable laser spectrometer, called SAM, which stands for Sample Analysis at Mars, detected the largest amount of methane ever measured during its mission. SAM has also found that over time, oxygen behaves in a way that can't be explained by any chemical process scientists currently understand.

SAM has had plenty of time -- about six years -- to sniff and analyze the atmospheric composition on Mars. The data revealed that at the surface, 95% of the atmosphere is carbon dioxide, followed by 2.6% molecular nitrogen, 1.9% argon, 0.16% oxygen and 0.06% carbon monoxide. Like Earth, Mars goes through its seasons; over the course of a year, the air pressure changes. This happens when the carbon dioxide gas freezes in winter at the poles, causing the air pressure to lower. It rises again in the spring and summer, redistributing across Mars as the carbon dioxide evaporates. In relation to the carbon monoxide, nitrogen and argon also follow similar dips and peaks. But oxygen didn't. Surprisingly, the oxygen actually rose by a peak increase of 30% in the spring and summer before dropping back to normal in the fall.

An anonymous reader quotes a report from CNBC: SpaceX launched another 60 of its internet satellites on Monday morning from Cape Canaveral, Florida, in a mission that set two new company records for reusing its rockets. Starlink represents SpaceX's ambitious plant to create an interconnected network of as many as 30,000 satellites, to beam high-speed internet to consumers anywhere in the world. This was the second full launch of Starlink satellites, as SpaceX launched the first batch of 60 in May. The company sees Starlink as a key source of funding while SpaceX works toward its goal of flying humans to and from Mars.

Monday's launch also represented the fourth mission for this SpaceX Falcon 9 rocket booster, which landed and was reused after three previous launches, making this the first time the company landed a rocket booster four times. The booster, the large bottom portion of the rocket, previously launched satellites and then landed successfully for missions in July 2018, October 2018 and February 2019. Additionally, SpaceX used a fairing (the rocket's nosecone) that the company fished out the Atlantic Ocean after a mission in April -- the first time a company has refurbished and used that part of a rocket again. The company has been working to catch the fairing halves in a net strung above the decks of two boats, using parachutes and onboard guidance systems to slowly fly the fairings back into the nets. SpaceX caught its first fairing half on a boat in June. "We deployed 60 more Starlink satellites. This puts us one step closer to being able to offer Starlink internet service to customers across the globe, including people in rural and hard to reach places who have struggled to access high speed internet," SpaceX engineer Lauren Lyons said on the webcast.

Researchers from MIT have developed a system that could help cars prevent collisions by, essentially, looking around corners. They call it ShadowCam. ExtremeTech reports: ShadowCam uses a sequence of four video frames from a camera pointed at the region just ahead of the car. The AI maps changes in light intensity over time, and specific changes can indicate another vehicle is approaching from an unseen area. This is known as Direct Sparse Odometry, a way to estimate motion by analyzing the geometry of a sequential image -- it's the same technique NASA uses on Mars rovers. The system classifies each image as stationary or dynamic (moving). If it thinks the shadow points to a moving object, the AI driving the car can make changes to its path or reduce speed.

The researchers tested this system with a specially rigged "autonomous wheelchair" that navigated hallways. ShadowCam was able to detect when a person was about to walk out in front of the wheelchair with about 70 percent accuracy. With a self-driving car in a parking garage, the researchers were able to tune ShadowCam to detect approaching vehicles 0.72 seconds sooner than lidar with an accuracy of about 86 percent. However, the system has been calibrated specifically for the lighting in those situations. The next step is to enable ShadowCam in varying light and situations.

Smithsonian magazine reports on a new study that concluded it may be possible to grow agricultural crops right in the soil of Mars -- and on the moon. For their paper in the journal Open Agriculture, researchers from Wageningen University & Research in the Netherlands planted ten different earthly crops in three types of soil. One was typical, garden-variety potting soil, another was simulated lunar dust, and a third was simulated Martian soil... Each Friday of the experiment, they added a nutrient-rich solution created to mimic the addition of human manure and urine that astro-colonists would likely add to their lunar farms. The crops planted in the soils included garden cress, rocket (aka arugula), tomato, radish, rye, quinoa, spinach, chives, peas and leeks.

Of those, the only vegetable that failed to grow well in the exo-soils was spinach. The radishes, cress and rye all grew to a point where seeds could be harvested. The team was also able to harvest tomatoes and peas from the lunar and Martian soils. The chives and leeks grew steadily, but slower than normal. While the quinoa produced flowers, it did not produce seeds. Still, the team reports that they suspect this is the first time any plants have been grown large enough to produce fruit in the soil simulants.

In a follow-up, the team were able to germinate the radish, cress and rye seeds produced on the Mars and lunar soils, suggesting that the production of self-sustaining crops might be possible in space.

NASA will send a golf cart-sized robot to the moon in 2022 to search for deposits of water below the surface, an effort to evaluate the vital resource ahead of a planned human return to the moon in 2024 to possibly use it for astronauts to drink and to make rocket fuel, the U.S. space agency said on Friday. From a report: The VIPER robot will drive for miles (km) on the dusty lunar surface to get a closer look at what NASA administrator Jim Bridenstine has touted for months: underground pockets of "hundreds of millions of tons of water ice" that could help turn the moon into a jumping-off point to Mars. "VIPER is going to assess where the water ice is. We're going to be able to characterize the water ice, and ultimately drill," Bridenstine said on Friday at the International Astronautical Congress in Washington. "Why is this important? Because water ice represents something significant. Life support." VIPER stands for Volatiles Investigating Polar Exploration Rover.

A reader shares a report from NASA: NASA's InSight spacecraft has used its robotic arm to help its heat probe, known as "the mole," dig nearly 2 centimeters (3/4 of an inch) over the past week. While modest, the movement is significant: Designed to dig as much as 16 feet (5 meters) underground to gauge the heat escaping from the planet's interior, the mole has only managed to partially bury itself since it started hammering in February 2019. The recent movement is the result of a new strategy, arrived at after extensive testing on Earth, which found that unexpectedly strong soil is holding up the mole's progress. The mole needs friction from surrounding soil in order to move: Without it, recoil from its self-hammering action will cause it to simply bounce in place. Pressing the scoop on InSight's robotic arm against the mole, a new technique called "pinning," appears to provide the probe with the friction it needs to continue digging.

Since Oct. 8, 2019, the mole has hammered 220 times over three separate occasions. Images sent down from the spacecraft's cameras have shown the mole gradually progressing into the ground. It will take more time -- and hammering -- for the team to see how far the mole can go. Engineers continue to test what would happen if the mole were to sink beneath the reach of the robotic arm. If it stops making progress, they might scrape soil on top of the mole, adding mass to resist the mole's recoil. If no other options exist, they would consider pressing the scoop down directly on the top of the mole while trying to avoid the sensitive tether there; the tether provides power to and relays data from the instrument.

"A consultant for NASA slammed the agency for deliberately ignoring the results of the experiment he handled that showed signs of alien life on Mars," reports the International Business Times. "According to the consultant, NASA refuses to conduct new life-detection tests on the Red Planet." Engineer Gilbert Levin served as a principal investigator on NASA's Viking missions, which sent two identical landers to Mars. For his role, Levin handled the missions' biological experiments known as Labeled Release (LR). These experiments focused on identifying living microorganisms on Mars. The experiments were sent to the Red Planet through the Viking 1 and Viking 2 missions in 1975....

"As the experiment progressed, a total of four positive results, supported by five varied controls, streamed down from the twin Viking spacecraft landed some 4,000 miles apart," Levin wrote in Scientific American. "The data curves signaled the detection of microbial respiration on the Red Planet," he continued. "The curves from Mars were similar to those produced by LR tests of soils on Earth. It seemed we had answered that ultimate question."

Despite the results of the LR experiment, the findings were discarded by NASA due to the agency's previous experiment on Mars.
More from Levin's article in Scientific American: Life on Mars seemed a long shot. On the other hand, it would take a near miracle for Mars to be sterile. NASA scientist Chris McKay once said that Mars and Earth have been "swapping spit" for billions of years, meaning that, when either planet is hit by comets or large meteorites, some ejecta shoot into space. A tiny fraction of this material eventually lands on the other planet, perhaps infecting it with microbiological hitch-hikers.

Hulu is finally allowing users to download TV shows and movies to their mobile devices to watch without an internet connection. Variety reports: The download feature, which has been several years in the works, gives Hulu subscribers on the $11.99 no-commercials plan the ability to download tens of thousands of TV episodes and movies. It's not available to customers who have the entry-level $5.99-per-month package with ads. For now, it's available only on Hulu's iOS app for Apple devices. The company says the feature will be coming to the Android app "soon."

The majority of Hulu's catalog, which includes some 85,000 total TV episodes, is available for offline viewing. That includes most Hulu originals, including full seasons of "The Handmaid's Tale," "Veronica Mars," "Shrill" and "The Act" as well as licensed content including "Family Guy," "Desperate Housewives," "This Is Us," "How I Met Your Mother" and "ER." A Hulu rep would not specify how much content is available to download for offline viewing, or spell out which TV shows or movies aren't included. The reason some content is excluded is that some of Hulu's past deals did not contemplate download rights. According to Hulu, customers can download a maximum of 25 titles across five different devices. Downloads are available for up to 30 days; they will expire two days after a user starts playback. After downloaded content expires, viewers can renew an expired download when they're connected online (assuming the content is still available on Hulu). The move comes nearly three years after Netflix added the feature , and four years after Amazon Prime Video added that ability for both iOS and Android apps. Disney Plus, which is launching on November 12, will also include content downloads.

On Tuesday, NASA posted several sonifications of data captured on Mars by InSight, a robotic lander that touched down on the red planet last year. From a report: InSight is the first mission ever to record "marsquakes" the Martian equivalent of earthquakes, which it detects with an instrument called Seismic Experiment for Interior Structure (SEIS), made by the French space agency. SEIS has now heard about 100 weird tremors rippling through the interior of Mars, 21 of which have been identified as likely marsquakes. For instance, here's an audio representation of a magnitude 3.7 marsquake detected on May 22, 2019, which was SEIS' 173th "sol" (the word for a Martian day) of operation. NASA dialed the seismic frequencies recorded by SEIS up to a range that can be heard by the human ear, but you may still need headphones to get the full experience. The quake sounds a bit like the kind of ambient bass-heavy hum you might expect to play during a tense scene in a movie thriller.

Aerospace startup Relativity Space -- the company that aims to launch the first fully 3D-printed rocket to orbit -- says it has raised all of the money it needs to launch its first mission and then enter commercial operations as early as 2021. After raising $140 million in its latest funding round, Relativity says its total funding now equals $185 million, which is enough money to carry the company through its first flights over the next couple of years. The Verge reports: Started by former engineers at Blue Origin and SpaceX, Relativity has grand ambitions to create all of its vehicles -- from the engines to the fuselage -- using 3D printing almost exclusively. The goal is to overhaul how rockets have been built for the last 50 years by taking people out of the manufacturing process and automating almost everything. By building rockets this way, Relativity claims it can drastically cut down costs by requiring fewer parts per rocket. Eventually, the company hopes to replicate this 3D-printing process on another world, like Mars, creating a rocket that can take off from the planet and return to Earth.

Right now, the company is focusing on its first rocket, the Terran 1, a small- to medium-sized vehicle being built with Relativity's specialized Stargate 3D printers in Los Angeles. Relativity says these updated printers could eventually create a Terran 1 rocket in less than 60 days from raw material. "Those are actually twice the print size of the prior version, and we have several of those already up and operational," says [Relativity Space CEO Tim Ellis] of the updated printers. Designed to stand about 100 feet tall, the Terran 1 rocket will be able to carry up to 2,755 pounds (1,250 kilograms) of payload, which is just 6 percent of the capacity of SpaceX's Falcon 9 rocket. However, the company says it has increased the size of the vehicle's nose cone, or payload fairing, making it able to hold twice the volume as originally planned.

Elon Musk has laid out an ambitious future for his spaceship project, the effort to deliver people to the moon and Mars. Marina Koren, writing for The Atlantic: The whole thing felt like an Apple event. The weeks of anticipation and breathless guesses from fans and critics. Onstage, the greatest-hits reel highlighting the company's beloved products over the years. A grand walk-through of the next product's features: the sleek design, the impressive specs, simulations of how it's going to work. A man with a mic, both salesman and visionary, looking out at the crowd. It is strange to compare the unveiling of a spaceship to the annual release of a smartphone, but this is the reality Elon Musk has conjured with SpaceX, and in a relatively short amount of time.

Musk gave a talk about SpaceX's prototype spaceship, Starship, on Saturday night in Boca Chica, Texas, a small coastal town not far from the U.S.-Mexico border, which SpaceX picked to house this ambitious project just a few years ago. The vessel, roomy enough to fit 100 passengers, will be shot into orbit by a massive, reusable rocket, which the company is also building and which could be as powerful as the Saturn V rocket that launched Apollo astronauts. Starship has multiple missions; it is supposed to shuttle people on swift journeys to different cities on Earth, as well as carry them on long-haul flights to the moon and Mars.

The event came 11 years after SpaceX reached orbit for the first time with the earliest version of its Falcon rockets. Since then, the company has flown rockets to orbit over and over again, then landed the accompanying boosters upright on the ground and reused them, an industry first for orbital missions. The company has launched commercial satellites, government spy missions, and cargo to the International Space Station. It shot a Tesla toward Mars and sprinkled internet satellites around Earth. Musk founded SpaceX to someday send people to Mars, and he has said for years that he will make space travel as easy as hopping on a plane. As he stood in front of a gleaming steel spaceship, it was tempting to start believing him. "It's really gonna be pretty epic to see that thing take off and come back," Musk said.

An anonymous reader writes: Elon Musk is speaking live right now on SpaceX's YouTube channel, promising an update on his plans for "Starship". Dressed entirely in black -- and joking about the wind -- he first thanked the SpaceX team, as well as its suppliers, for an "incredible vehicle....the most inspiring thing I've ever seen" and then promised tonight's speech would "inspire the public and get people excited about our future in space." In addition to solving earth's problems, he said, "We also need things that make us glad to be alive...and be fired up about the future... Space exploration is one of those things."

He also says it's possible for us to become a space-faring civilization, "being out there among the stars," adding "We're faced with a choice. Which future do you want?" Looking back over the history of SpaceX, he describes their goal of creating a rapidly reusable -- and fully reusable -- rocket, and traces their progress on a long-term goal "to make space travel like air travel." (He calls earth "a deep gravity well" with a thick atmosphere, adding "this is a tough but not impossible thing.")

But is he preparing a bigger announcement?
UPDATE (9/29/2019): Summarizing the event, The Los Angeles Times reported that "A prototype of SpaceX's Starship Mars spaceship could reach orbit in less than six months and fly humans next year... Musk did not give an updated timeline for when Starship -- essentially a second-stage rocket and lander -- would go to Mars. SpaceX has said its 'aspirational goal' is to send cargo missions to the Red Planet in 2022."

GeekWire added that SpaceX is also "working on technologies to convert carbon dioxide from Mars' atmosphere and water ice extracted from Martian soil into methane and oxygen, which are the propellants for Starship's Raptor engines."

"In response to a question, Musk said the tunneling technologies being pioneered by another one of his ventures, the Boring Company, could come in handy for building underground habitats Mars. And he acknowledged that Tesla's electric-vehicle technology could be applied to Mars rovers as well. 'Teslas will work on Mars...because electric cars don't need air."

NASA engineers want to create a rocket engine powered by nuclear fusion. "A nuclear rocket engine would be twice as efficient as the chemical engines powering rockets today," reports Wired. "But despite their conceptual simplicity, small-scale fission reactors are challenging to build and risky to operate because they produce toxic waste. Space travel is dangerous enough without having to worry about a nuclear meltdown. But for future human missions to the moon and Mars, NASA believes such risks may be necessary." From the report: At the center of NASA's nuclear rocket program is Bill Emrich, the man who literally wrote the book on nuclear propulsion. "You can do chemical propulsion to Mars, but it's really hard," says Emrich. "Going further than the moon is much better with nuclear propulsion." Emrich has been researching nuclear propulsion since the early '90s, but his work has taken on a sense of urgency as the Trump administration pushes NASA to put boots on the moon ASAP in preparation for a journey to Mars. Although you don't need a nuclear engine to get to the moon, it would be an invaluable testing ground for the technology, which will almost certainly be used on any crewed mission to Mars.

Let's get one thing clear: A nuclear engine won't hoist a rocket into orbit. That's too risky; if a rocket with a hot nuclear reactor blew up on the launch pad, you could end up with a Chernobyl-scale disaster. Instead, a regular chemically propelled rocket would hoist a nuclear-powered spacecraft into orbit, which would only then fire up its nuclear reactor. The massive amount of energy produced by these reactors could be used to sustain human outposts on other worlds and cut the travel time to Mars in half. [...] But before a nuclear rocket engine gets its first flight, NASA needs to overhaul its regulations for launching nuclear materials. In August, the White House issued a memo that tasked NASA with developing safety protocols for operating nuclear reactors in space. Once they're adopted by NASA, the stage will be set for the first flight of a nuclear engine as soon as 2024. This coincides with Trump's deadline to return American astronauts to the moon; maybe this time they'll be hitching a ride on a nuclear rocket.

Applehu Akbar writes: CNN reports this week on a paper describing a hypothesis that the breakup of a large asteroid 466 million years ago generated enough dust in Earth's orbit to substantially change the terrestrial climate for an extended period. This would have triggered an 'Ordovician icehouse' climate event, with major effects on biology.
"The 93-mile-wide asteroid was in the asteroid belt located between Mars and Jupiter when it collided with something else and broke apart, creating a wealth of dust that flooded the inner solar system..." CNN reports. "To understand how this process unfolded, the researchers found evidence of space dust locked in 466-million-year-old rocks that were once on the sea floor."

The paper argues that to this day, that collision "still delivers almost a third of all meteorites falling on Earth."

Initial results from NASA's InSight lander suggest that Mars' magnetic field wobbles in inexplicable ways at night, hinting that the red planet may host a global reservoir of liquid water deep below the surface. National Geographic reports: In addition to the odd magnetic pulsations, the lander's data show that the Martian crust is far more powerfully magnetic than scientists expected. What's more, the lander has picked up on a very peculiar electrically conductive layer, about 2.5 miles thick, deep beneath the planet's surface. It's far too early to say with any certainty, but there is a chance that this layer could represent a global reservoir of liquid water.

On Earth, groundwater is a hidden sea locked up in sand, soil, and rocks. If something similar is found on Mars, then "we shouldn't be surprised," says Jani Radebaugh, a planetary scientist at Brigham Young University who was not involved with the work. But if these results bear out, a liquid region at this scale on modern Mars has enormous implications for the potential for life, past or present. So far, none of these data have been through peer review, and details about the initial findings and interpretations will undoubtedly be tweaked over time. Still, the revelations provide a stunning showcase for InSight, a robot that has the potential to revolutionize our comprehension of Mars and other rocky worlds across the galaxy.

In new research published on Thursday in the journal Joule, Dr. Raman, an electrical engineer at the University of California, Los Angeles, demonstrated a way to harness a dark night sky to power a light bulb. The New York Times reports: His prototype device employs radiative cooling, the phenomenon that makes buildings and parks feel cooler than the surrounding air after sunset. As Dr. Raman's device releases heat, it does so unevenly, the top side cooling more than the bottom. It then converts the difference in heat into electricity. In the paper, Dr. Raman described how the device, when connected to a voltage converter, was able to power a white LED. The prototype built by Dr. Raman resembles a hockey puck set inside a chafing dish. The puck is a polystyrene disk coated in black paint and covered with a wind shield. At its heart is an off-the shelf gadget called a thermoelectric generator, which uses the difference in temperature between opposite sides of the device to generate a current. A similar device powers NASA's Curiosity rover on Mars; its thermoelectric generator derives heat from plutonium radiation. Usually, the temperature difference in these generators is stark, and they are carefully engineered to separate hot and cold. Dr. Raman's device instead uses the atmosphere's ambient temperature as the heat source. The shift from warm to cool is very slight, meaning the device can't produce much power.

His puck-in-a-dish is elevated on aluminum legs, enabling air to flow around it. As the dark puck loses warmth to the night sky, the side facing the stars grows colder than the side facing the air-warmed tabletop. This slight difference in temperature generates a flow of electricity. When paired with a voltage converter, the prototype produced 25 milliwatts of power per square meter. That is about three orders of magnitude lower than what a typical solar panel produces, and well short of even the roughly 4-watt maximum efficiency for such devices. Still, several experts said the prototype was an important contribution to a new and relatively unusual space in the renewable energy sector.

Tesla CEO Elon Musk and Alibaba founder Jack Ma discussed Mars and artificial intelligence in their first joint appearance on Thursday. From a report: The duo chatted for over half an hour about their vision of how technology, especially artificial intelligence, will shape the future. "I'm always amazed by your vision of technology, I'm not a tech guy," Ma said in his first remarks to Musk, before going on to talk about how artificial intelligence was not a threat. Ma described himself as "optimistic" about AI's impact on humanity, adding that people who worry too much about it have what he calls "college smartness." "People like us that are street smart, we're not scared of that." They also went on to talk about space travel, with Ma complimenting Musk on his attempts to journey into Mars via SpaceX while Musk noted China's advancements in that area, as well as how "inadequate" humans were against computers. Ma, known for arguing in favor of a 12-hour workday, also said he sees a future in which people will have to work only 12 hours a week. He said technological advancements would enable people to live longer and work far fewer hours. He added: "Every technology revolution, people start to worry. In the last 200 years, we have worried [that] new technology is going to take away all the jobs," he said. Ma has previously courted controversy with his endorsement of the "996" work practices prevalent in China's tech industry, under which employees are expected to work 9 a.m. to 9 p.m., six days a week.

An anonymous reader quotes Business Insider: A small community of people at the southern tip of Texas just received what some of its residents are calling a "shocking" and "concerning" warning about SpaceX's upcoming launch attempt of a Mars rocket ship prototype. Residents told Business Insider a county sheriff went door-to-door on Saturday night to hand-deliver printed notices to the community, where approximately 20 people own homes...

The notice says "action required" and warns of "potential risk to health and safety" during SpaceX's upcoming launch attempt of Starhopper: a stubby yet roughly 60-foot-tall (18-meter-tall) steel prototype with a single, truck-size Raptor rocket engine... The notice issued to residents says police will sound their sirens to warn residents about 10 minutes before liftoff. According to the notice, a roughly 15-minute flight window will open at 5 p.m. ET (4 p.m. CT) on Monday night. The notice then says:

"There is a risk that a malfunction of the SpaceX vehicle during flight will create an overpressure event that can break windows. Therefore, in order to protect Public Health and Safety, it is recommended that you consider temporarily vacating yourself, other occupants, and pets, from the area during the Space Flight Activities. At a minimum, you must exit your home or structure and be outside of any building on your property when you hear the police sirens which will be activated at the time of the Space Flight Activity to avoid or minimize the risk of injury."

An "overpressure event" is a blastwave that's often caused by a rapid explosion...

The public health and safety notice comes about a month after SpaceX's most recent launch of Starhopper. That flight inadvertently ignited a grass fire that burned through more than 100 acres of coastal wildlife refuge, thousands of acres of which surround the launch site and hamlet. SpaceX has responded to the incident by putting together a better fire-prevention and response plan, according to Bryan Winton, manager of the Lower Rio Grande Valley national wildlife refuge at the US Fish and Wildlife Service. SpaceX is now coordinating more closely with local agencies on its launch plans and fire safety, has installed five new remote-control water cannons on its launchpad to douse flames (there used to be only one), is helping perform controlled burns, and more, Winton told Business Insider on Thursday.

New submitter RhettLivingston writes: Real plans for the move of Starship Mk 2 from its current construction site in Cocoa to the Kennedy Space Center have finally emerged. A News 6 Orlando report identifies permit applications and observed preparations for the move,which will take a land and sea route. Barring some remarkably hasty road compaction and paving, the prototype will start its journey off-road, crossing a recently cleared path through vacant land to reach Grissom Parkway. It will then travel east in the westbound lanes of SR 528 for a short distance before loading to a barge in the Indian river via a makeshift dock. The rest of the route is relatively conventional, including offloading at KSC at the site previously used for delivery of the Space Shuttle's external fuel tanks. Given the recent construction of new facilities at the current construction site, it is likely that this will not be the last time this route is utilized. SpaceX declined to say how the company will transport the spacecraft or when the relocation will occur.

SpaceX's "Mk2" orbital Starship prototype is designed to test out the technologies and basic design of the final Starship vehicle -- a giant passenger spacecraft that SpaceX is making to take people to the Moon and Mars.

"Elon Musk tweeted on Thursday evening 'Nuke Mars.' A few hours later he followed it up with 'T-shirt soon'," writes Business Insider.

BGR reports: Musk's tweet is a reference to the theory that by dropping one or more large bombs on Mars' poles, the CO2 locked away in the ice there would be released, giving the Martian atmosphere a much-needed boost... Making the planet's atmosphere denser could help it retain heat and bring it a small step closer to being habitable by human settlers. However, past research has suggested that bombing the planet's poles wouldn't release nearly enough CO2 to be worth the trouble. Elon Musk has publicly disagreed.

It's unclear why the SpaceX boss decided to bring this all up again, but he does have a habit of saying whatever he thinks will get a big reaction on Twitter. Oh, and apparently he's hoping to sell some shirts as well.

In any case, no space agency is ready to even begin preliminary planning for a crewed Mars mission, much less any long-term efforts to change the climate of the Red Planet. If that ever does happen, bombs may or may not play a role.
The article adds that scientists "aren't fully on board" with Musk's line of thinking, but the t-shirts really are available in the online SpaceX store. Late Friday Musk began promoting them with an optimistic tweet.

"Nuking Mars one T-shirt at a time."