Scientists may have found the first moon outside our Solar System – depending on what astronomers ultimately decide counts as one. Either way, the groundbreaking research, published in Nature this week, promises a path to clearer sightings of so-called exomoons. Kevin Hoy, a PhD student affiliated with Universidad Diego Portales and the European Southern Observatory in Chile, has found an object orbiting a brown dwarf, which in turn orbits a host star, which sits about 73 light-years from the Sun in the southern celestial hemisphere. Brown dwarfs present a problem for astronomers. They fill the gap between gas giant planets – like Jupiter or Saturn – and the smallest stars. They are not massive enough to sustain the hydrogen fusion that powers the Sun and other main-sequence stars, although they can fuse deuterium, a heavier isotope of hydrogen. That leaves the object found by Hoy and his collaborators in a definitional gray area. "This is the first time, to our knowledge, this technique has produced evidence of satellites around a companion brown dwarf," the paper said. The first confirmed exoplanets were discovered orbiting a pulsar in 1992, but exomoons have so far proved elusive, despite there being hundreds in our own Solar System. The researchers found that the new object, which for now they are calling an exosatellite, is decidedly unmoon-like, being at least as massive as Jupiter. The brown dwarf it orbits is around 30 times the mass of Jupiter. "This system is somewhat hard to define using Solar-System-based words like 'planet' and 'moon,'" Hoy said in a statement. "The exosatellite is clearly massive enough to be a planet, but it does not orbit a star, though it orbits an object that orbits a star. Being the third wheel in this system makes us want to call it a moon, even if it is nothing like the small, rocky moons we have in our system." The research team employed the radial velocity method used by Michel Mayor and Didier Queloz to discover 51 Pegasi b in 1995, the first exoplanet found orbiting a Sun-like star. The technique detects the gravitational "wobble" induced in a host object – usually a star, but in this case a brown dwarf – by something orbiting it. Modeling of the data indicates that there is at least one orbiting satellite. Models for two satellites are possible but highly unstable. Whether a moon or not, the object has a minimum mass about nine-tenths that of Jupiter and completes an orbit every 170 days. "Although it is uncertain whether this exosatellite will fulfil the presently undefined criteria for qualifying as an exomoon, it is a marked step towards that first uncontroversial detection, as advancing technology will allow the same method to be applied to less massive targets," the paper says. At roughly Jupiter's mass, this is no forest moon of Endor. Finding something more like the moons in our own neighborhood will have to wait for sharper instruments. ®

It has been half a century since NASA landed on Mars with the Viking 1 lander. Viking 1, one of a pair of Viking spacecraft, landed on Mars on July 20, 1976. Launched on August 20, 1975, Viking 1 arrived in orbit around Mars on June 19, 1976. The Viking program is, when adjusted for inflation, one of the most expensive robotic missions ever attempted by NASA. The spacecraft consisted of an orbiter, which was eventually shut down on August 7 as its attitude control gas was depleted, and a lander, which became the longest-lived component of the Viking program (and even then, it was only human error that did it in). The original plan had called for a landing on Mars on July 4, 1976, to coincide with the US Bicentennial, but a look at the potential landing site made managers postpone the descent to July 20 – the seventh anniversary of the Apollo 11 lunar landing – and a safer destination. The lander was equipped with an ablative heat shield to withstand atmospheric entry. Parachutes slowed the lander as it descended, and retro-rockets fired just above the surface to ensure the three-legged Viking lander reached Martian soil without incident. Viking 1 landed on Mars' Chryse Planitia. It performed the first sampling of Martian soil using its robotic arm and an onboard biological laboratory. While the official word from NASA is that no definitive signs of life were found, debate has continued over the decades that… perhaps… there was something else in the data from the robots. NASA's take was that the "experiments discovered unexpected and enigmatic chemical activity in the Martian soil, but provided no clear evidence for the presence of living microorganisms in soil near the landing sites." Findings from onboard experiments aside, the lander was also equipped with cameras capable of snapping breathtaking vistas of the surface, as well as antennas for communicating with the Viking 1 orbiter, which acted as a relay, and directly with Earth. Crucially, the lander was also powered by a Radioisotope Thermoelectric Generator (RTG), which uses the heat from the decay of plutonium-238 fuel to generate electricity. This played an important role in keeping the Viking 1 lander running past its 90-day prime mission all the way to when it made its final transmission on November 11, 1982. The mission might have gone on longer if it had not been for a mistake made when engineers were devising ways [PDF] of prolonging the life of the lander's batteries. In January 1982, three of Viking 1's four nickel-cadmium batteries were showing signs of wear. Engineers attempted deep-discharge battery conditioning to bring things closer to where they had been at the start of the mission, but the results were only partially successful (with benefits being very temporary). So, a different approach was tried. Rather than discharge the batteries for a specific time, engineers would have Viking 1 go for a known voltage. There would be a reduction in the frequency and duration of battery charging. Engineers reckoned the plan would prolong the life of the batteries and, on November 19, 1982, the changes for the battery charging sequence were uploaded… and… silence. The expected downlink from Viking 1 did not appear, and on November 20, a spacecraft emergency was declared. It transpired that the new battery charging sequence had been written to memory locations occupied by the lander's high-gain antenna pointing parameters. As a result, the antenna was no longer pointing at Earth. The next four months were spent trying to contact the lander, but to no avail. In March 1983, the Viking Lander Monitor Mission (VLMM) was terminated. Still, that was all in the future when Viking 1 landed half a century ago. Viking 1 wasn't the first spacecraft to make a soft landing on Mars – that prize goes to the Soviet Union's Mars 3 lander in 1971 (although transmissions ended 20 seconds after landing compared to the years of operation for Viking 1), but it produced spectacular imagery and a trove of science data and, coming just seven years after the first crewed lunar landing, was a triumph for the US space agency. ®

UPDATED SpaceX's 13th Starship flight test ended at the launchpad after four Raptor engines failed to start, triggering an automatic abort moments before liftoff. Elon Musk's biz ignited the booster's engines at 2245 UTC on July 16, but the automated system aborted the launch. The boss confirmed: "Some of the engines didn't start, triggering an automatic launch abort… To be confident of a good flight, two Raptors will be removed and replaced. Most probable launch timing is early next week." The nature of the problem is not clear, nor is whether the vehicle will need to be de-stacked for engine replacement. Although the abort showcased the booster's anomaly-detection capabilities, it is not a great look for a rocket that must launch multiple times in quick succession to meet the requirements of the Artemis IV Moon landing planned for 2028. Flight Test 13 marks the second test of Starship's V3 configuration. The vehicle hasn't reached orbit, but a successful test - one that demonstrates engine reignition in space - would likely let SpaceX move beyond suborbital flights. That shift is urgent as Artemis III is scheduled to launch next year, and Starship must be qualified for orbital operations by then. The abort won't have done SpaceX stock any favors. Investors had already brought it back to Earth after an early surge made Musk a trillionaire (on paper). By the close of trading, shares had slid to just over $131, below the $135 initial public offering price that valued the loss-making biz at roughly $1.78 trillion. NASA is paying close attention. The agency confirmed yesterday it will use SpaceX's Starlink to deliver Artemis III imagery from Orion. It'd be a shame if that imagery didn't include a rendezvous with Starship because SpaceX is unable to get the behemoth off the ground, let alone into orbit. Despite Musk's suggestions of "early next week," SpaceX has yet to officially confirm a date for the next Starship launch attempt. ® Updated at 8.57 UTC on July 20, 2026, to add: SpaceX has announced that it will try again "as early as Thursday, July 23."

NASA has given an update on the Artemis III mission and, while sticking with an optimistic 2028 landing target for Artemis IV, offered a glimpse into just how much development work remains to be done at Blue Origin and SpaceX. Artemis III has been compared to Apollo 9, which tested the Apollo Lunar Module in Earth orbit, yet neither SpaceX nor Blue Origin is flying anything as close to the lunar landers. Blue Origin's test lander will be based on the company's current Mark 2 crew lander architecture, incorporating the major avionics, flight software, life support, and crew cabin. Orion, launched atop NASA's SLS, will dock to the side of the Blue Origin spacecraft for crew transfer; two crew members in orange Orion survival suits can board the test lander, with Orion's software controlling the stack. An instrumented lunar surface spacesuit mass simulator, similar to the "Moonikin" manikin that flew aboard Orion for Artemis I, will also ride along on the Blue Origin lander. SpaceX's test is considerably simpler - just a docking system mounted on the nose of a Starship. That requires Starship testing to have reached the orbital stage first, which is why NASA will be closely watching the upcoming Flight Test 13. Starship V3 is still flying suborbital until SpaceX proves it can reliably relight an engine for controlled re-entry. Under the current plan, Blue Origin launches its lander into orbit first, where it can loiter for up to 30 days. Once it's checked out, a crew launches aboard Orion to rendezvous and dock with it. After that's complete, SpaceX launches its Starship test article to rendezvous and dock Orion in turn, though the crew won't board Starship, just verify communications and interoperability. SpaceX's vehicle will control that docked stack. Notably, SpaceX's docking capability was qualified in 2023, while Blue Origin only tested its pressurized docking system earlier this year. Jeremy Parsons, Artemis program manager, stated, "Artemis III will be a highly choreographed dance with a demanding launch sequence across multiple launch pads and equally demanding mission operations for our ground and flight crews, making it one of the most complex and ambitious missions NASA has ever undertaken." He is not exaggerating. Apollo 9 needed a single Saturn V launch; Artemis III needs three – an SLS, whatever Blue Origin ultimately uses to launch its lander (the company is still rebuilding its launch pad after May's explosion), and a Starship. The SLS has flown twice, including one lunar flyby. Starship has yet to reach orbit despite Elon Musk once claiming that uncrewed versions would be landing on Mars around now. It'll be an impressive feat if NASA can pull it off, even if SpaceX's piece of the puzzle looks a lot simpler than Blue Origin's. ®

NASA has performed a rocket switcheroo and will launch its SunRISE mission on a SpaceX Falcon Heavy instead of the United Launch Alliance (ULA) Vulcan Centaur on which it was originally booked to fly. The mission is flying as a rideshare sponsored by the United States Space Force's Space Systems Command, which might go some way to explaining the decision to change the launch vehicle. In February, the fourth Vulcan Centaur flight experienced a booster anomaly during a US Space Force launch. The payload made it to orbit, but a burn-through of a Solid Rocket Booster (SRB) nozzle made the trip more eventful than planned. Space Force reportedly paused all national security launches on the Vulcan Centaur until the investigation was complete and appropriate corrective action taken. This left SunRISE in a pickle as it was due to launch on a Vulcan Centaur this summer, having completed its final prelaunch testing at the beginning of 2026. NASA said it "will share updated launch timing in the near future," although some time in 2027 seems a safe bet. There could be two Falcon Heavy launches in the remainder of 2026: one for the Nancy Grace Roman Space Telescope and another for Astrobotic's Griffin Mission One. Several US Space Force launches are planned for 2027, and SunRISE is likely to hitch a ride on one of them. SunRISE (Sun Radio Interferometer Space Experiment) consists of six small satellites operating as one giant radio telescope slightly above geosynchronous orbit. The satellites will fly approximately 6 miles (10 kilometers) apart, and deploy four radio antennas each, extending 10 feet (2.5 meters). Construction of the six spacecraft was completed in 2023. According to NASA, "the six SmallSats will act as a single, giant radio telescope to capture in unprecedented detail data on the radio bursts associated with the Sun's particle storms." That's assuming the vehicles ever make it off the ground. The Vulcan Centaur launch was expected in summer 2026, but the switch to Falcon Heavy suggests NASA and the Space Force are hedging against further delays to Vulcan's return to national security launches. ®

Indian Space Research Organisation (ISRO) has successfully tested systems it plans to use on the nation's first crewed space mission, but when that mission will launch remains a mystery. ISRO's crewed mission program, "Gaganyaan," is intended to carry astronauts on a rocket called the Human-Rated Launch Vehicle Mark 3 (HLVM3) into orbit. The space agency has already launched the cargo-rated version of the three-stage LVM3 rocket nine times and has a perfect success rate. When India launches humans into space, they'll occupy a crew module. On Sunday, ISRO announced it had successfully accomplished three major qualification tests for that module. One test qualified the primary flotation unit in the system designed to right the crew module after splashdown. Another tested the mechanism that disconnects the umbilical links between the crew and service modules. The third assessed whether the crew module structure could withstand the loads generated when the cover protecting its parachutes separates. The tests are the latest in a long series of qualification milestones for Gaganyaan. Last July, ISRO tested the Service Module Propulsion System (SMPS) and proclaimed it ready to raise and maintain its orbit, handle an emergency mission abort, and perform the deorbit maneuvers ahead of re-entry. However, the agency has had little to say about when Gaganyaan will fly. ISRO initially targeted 2022 for the first crewed Gaganyaan flight, then changed the date to 2024, before scheduling an uncrewed flight carrying a robot astronaut for 2025. ISRO missed that deadline too. Officials and ministers have since suggested test flights could take place in 2027, followed by crewed missions in 2028. But the agency has never published a firm timeline. That caution is understandable because space is hard and the stakes are high for any crewed mission – never mind a mission that would make India just the fourth nation to launch humans into space. ®

Scientists have detected a sugar in interstellar space, suggesting the galaxy may be liberally sprinkled with some of life's chemical ingredients. A new study shows that a sugar molecule containing four carbon atoms, called erythrulose, has been found near the center of the Milky Way, the first confirmed detection of a monosaccharide in the interstellar medium. Living organisms use sugars as energy sources, structural components, and constituents of genetic material. While scientists have previously found ribose and glucose in meteorite and asteroid samples, indicating they also exist in space, monosaccharide forms of sugar in deep space had remained elusive – if we're not counting glycolaldehyde, which is often loosely described as the simplest sugar, or a sugar precursor. Astrobiology researcher Izaskun Jiménez-Serra and her colleagues found the sugar in large clouds of gas and dust near the center of our galaxy using ultrasensitive spectral surveys performed by Spain's Yebes 40-meter and IRAM 30-meter radio telescopes. The researchers identified the sugar compound by matching 12 sets of signals in the survey data with erythrulose's laboratory-measured spectral signature. "Erythrulose appears to be at least eight times more abundant than analogous three-carbon sugars, which remain undetected in our ultrasensitive observations," says the paper, published in Nature Astronomy this week. Quantum chemical and astrochemical models indicate that erythrulose forms efficiently on interstellar dust grains from simpler two-carbon molecules, the study found. The researchers say the findings suggest that erythrulose can be made from simpler molecules on dust grains in space, eventually becoming part of more complex chemical systems. "The discovery of interstellar erythrulose suggests that the interstellar medium could be a viable source of sugar feedstock for the prebiotic synthesis of the first nucleic acids, not only on the primitive Earth but also elsewhere in the Universe," the paper states. While the discovery of sugars in deep space may be tantalizing for any budding explorers of the galaxy, there's no need to travel that far to find erythrulose. It occurs naturally on Earth, including in raspberries. ®