This weekend's Astronomy Daily wraps up the biggest stories from across the cosmos, starting with two completely fresh discoveries — a 1976 ocean rock that's turned out to hold atomic-scale proof of an ancient neutron star collision, and a record-breaking rocket launch from Europe's Ariane 6. Then we wind back through the week for our four biggest headlines: a new crew for Artemis III, JWST's salty 'Pink Planet' discovery, an update on the daring Swift Observatory rescue mission, and China's Tianwen-2 closing in on its target asteroid. Story 1: A Kilonova's Fingerprint, Found in a 1976 Ocean Rock • A rock sample dredged from the Pacific seafloor in 1976 has been found to contain a few hundred atoms of plutonium radioisotopes. • The plutonium originated from a kilonova — a collision between two neutron stars — that occurred over 100 million years ago. • Stellar debris from the merger settled to Earth and was slowly incorporated into a ferromanganese crust on the ocean floor. • Isotope ratios provide the strongest physical clues yet to what created the elements and roughly when the merger occurred. • Study published 18 June 2026. Story 2: Ariane 6 Smashes Its Own Heaviest-Payload Record • On 17 June 2026, an Ariane 64 rocket launched 36 Amazon Leo satellites from French Guiana (mission VA269 / LE-03). • First flight of new P160C solid boosters — about a metre longer than the previous P120C, holding up to 156 tonnes of propellant each. • Boosters deliver roughly a 10% performance increase, raising Ariane 64's LEO capacity to approximately 22 tonnes. • The mission broke the 13-year record for heaviest payload ever launched by an Ariane rocket, previously held by the 2013 ATV 'Albert Einstein' resupply flight. • Eighth Ariane 6 launch overall; 100th Amazon Leo satellite deployed by Arianespace. Story 3: Artemis III Crew Revealed • NASA announced the Artemis III crew on 9 June 2026 at Johnson Space Center: Commander Randy Bresnik, Pilot Luca Parmitano (ESA), and Mission Specialists Frank Rubio and Andre Douglas, with Bob Hines as backup. • The Artemis II crew (Wiseman, Glover, Koch, Hansen) symbolically passed their lunar baton to the new crew. • Artemis III is a two-week test flight in low Earth orbit to test docking procedures between Orion and commercial landers from SpaceX and Blue Origin. • Targeted for launch as early as late 2027, ahead of a planned lunar surface landing in 2028. • Will be Andre Douglas's first spaceflight. Story 4: JWST Cracks the 'Pink Planet' Mystery • JWST has confirmed salt clouds in the atmosphere of GJ504b, the 'Pink Planet,' located 57 light-years away. • First direct evidence of salt clouds on a cold substellar companion object, a phenomenon theorised 15 years ago. • At approximately 550°F, GJ504b is the coldest companion object ever directly imaged. • Its true nature remains uncertain — it may be a giant planet or a brown dwarf. • Research led by a Northwestern University team. Story 5: The Swift Rescue Mission Heads for the Pacific • NASA's Neil Gehrels Swift Observatory (orbiting since 2004) faces premature reentry due to orbital decay accelerated by recent solar activity. • Katalyst Space Technologies' LINK robotic servicing spacecraft will attempt to grapple and boost Swift to a safer ~600km orbit. • LINK launches on a Northrop Grumman Pegasus XL rocket, carried by Stargazer, the last flying Lockheed L-1011 TriStar. • Stargazer departed NASA Wallops Flight Facility on 18 June 2026, en route to Kwajalein Atoll via California and Hawai'i. • Launch targeted for 27 June 2026; if successful, it will be the first capture of an unprepared US government satellite by a commercial vehicle. Story 6: Tianwen-2 Closes In on Kamo'oalewa • China's Tianwen-2 spacecraft, launched May 2025, completed orbital insertion at near-Earth asteroid Kamo'oalewa on 7 June 2026. • Amateur radio trackers in Germany detected fine ion-engine course-correction burns between 11–14 June 2026. • Rendezvous and sample collection are expected around 4 July 2026. • Kamo'oalewa is a 40–100 metre quasi-satellite of Earth; its origin (possibly a lunar fragment) remains scientifically debated. • After sample return, Tianwen-2 will travel on to rendezvous with comet 311P/PanSTARRS in 2035.
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[00:00:00] Hello and welcome to Astronomy Daily, your daily dose of space news from across the cosmos. I'm Anna. And I'm Avery. It's Saturday the 20th of June, 2026, and that means it's time for our weekend space and astronomy news wrap. As always, we're kicking things off with two brand new stories you won't have heard anywhere else on the show, including a genuinely goosebump-inducing tale about a rock pulled up of the Pacific Ocean 50 years ago
[00:00:29] that's just rewritten part of cosmic history. Then we'll wind back to the week and bring you the four biggest stories that had everyone talking. A new crew for the moon, a salty pink world, a daring rescue mission, and an asteroid chase 50 years in the making. If you're watching on YouTube, smash that subscribe button, and let's get straight into it. Let's start with a story that genuinely gave me chills, Anna.
[00:00:54] Back in 1976, a research expedition hauled up a small lump of rock from the floor of the Pacific Ocean. Nobody at the time had any idea what they were really holding. Fifty years later, scientists have worked out exactly what's hiding inside it, and it's older and stranger than anyone expected. The rock is a chunk of what's called ferro-manganese crust, basically slow-growing mineral deposits that build up on the seafloor over millions of years, almost like tree rings.
[00:01:23] And buried inside this particular piece are a few hundred atoms, atoms, not grams, of radioactive plutonium isotopes. Which doesn't sound like a lot, because it isn't. But those atoms didn't come from anywhere on Earth. More than 100 million years ago, two neutron stars, the impossibly dense leftover cores of giant stars, crashed into each other in a cataclysmic event called a kilonova. And a kilonova is basically a heavy element factory.
[00:01:53] The collision is so violent and so energetic that it forges elements far heavier than iron, including gold, platinum, and yes, plutonium. That blast sent a rain of these freshly minted elements out across space. Some of that stellar debris eventually drifted down to our solar system, through Earth's atmosphere, and settled into the ocean, where over unimaginable spans of time, it got slowly locked into this growing crust of rock on the seafloor.
[00:02:22] The study was published just yesterday. And what's remarkable is that the ratios of these plutonium isotopes act almost like a fingerprint. They give researchers their strongest physical clues yet about exactly what kind of event created them, and roughly how long ago it happened. It's wild to think Earth has basically been an accidental evidence locker this whole time, quietly filing away atomic-level proof of cosmic violence
[00:02:49] before there was complex life on this planet at all. A little lump of rock, dredged up half a century ago, finally giving up one of its biggest secrets. Beautiful story. From ancient cosmic violence to some very modern rocket engineering, Europe's Ariane 6 just broke a record that had stood for 13 years. This happened on Wednesday, the 17th of June. An upgraded Ariane 6-4 lifted off from Europe's spaceport in French Guiana,
[00:03:18] carrying 36 Amazon LEO broadband satellites. That's the constellation formerly known as Project Cooper. 36 satellites doesn't sound like a record breaker on its own, but here's the kicker. This was the very first flight of Ariane 6-4's new P-160 boosters. They're an upgrade on the previous P-120 boosters, about one meter longer and able to hold up to 156 tons of propellant each.
[00:03:43] That gives roughly a 10% performance boost and pushes Ariane 6-4's lift capacity to about 22 tons to low Earth orbit. Combined with those 36 satellites, it added up to the heaviest payload ever launched by an Ariane rocket, beating a record that had stood in 2013 when an Ariane 5 delivered the ATV cargo vehicle Albert Einstein to the International Space Station.
[00:04:09] The satellites were deployed into orbit about 465 kilometers up over the course of just under two hours, and Ariane Space confirmed every single one separated successfully. This was also the eighth Ariane 6 launch overall, and the hundredth Amazon LEO satellite lofted by Ariane Space specifically, out of a planned 18 launch contract with Amazon. It's a solid milestone for a rocket that, let's be honest,
[00:04:38] had a famously bumpy road to its 2024 debut. And it matters beyond the bragging rights. Amazon's been racing against an FCC deadline to get half its constellation up by the end of July, competing for SkySpace against SpaceX's Starlink, which already has more than 10,000 satellites in orbit. Whichever side of the satellite mega-constellation debate you sit on, watching Europe's flagship rocket flex some genuinely upgraded muscle is fun to see.
[00:05:07] And that brings us to the part of the show you've been waiting for, our look back at the four biggest stories that shaped the week in space and astronomy. We've got updates on a couple of these too, so even if you caught them earlier in the week, stick around, there's fresh detail in each one. Story number three, and for my money, the biggest human spaceflight story of the week. On Tuesday, NASA finally named the crew for Artemis 3. At a ceremony in Houston,
[00:05:34] NASA Administrator Jared Isaacman introduced the four astronauts who will fly this critical test mission. Commander Randy Bresnik, ESA pilot Luca Parmitano, and mission specialists Frank Rubio and Andre Douglas. Bob Hines will train alongside them as backup crew. And here's the bit that got me. Towards the end of the ceremony, the Artemis 2 crew, Reed Wiseman, Victor Glover, Christina Cook, and Jeremy Hansen,
[00:06:01] physically handed over the baton they carried around the moon and back in April, passing it to Bresnik's crew as a symbol of the relay continuing toward the lunar surface. Now, important distinction here. Artemis 3 isn't the landing mission itself. It's a two-week test flight that stays in low Earth orbit, designed to test rendezvous and docking procedures between the Orion spacecraft and the commercial landers being built by SpaceX and Blue Origin.
[00:06:29] Think of it as the Artemis program's equivalent of Apollo 9, proving the hardware works together before anyone attempts an actual landing. It's currently targeted for as early as late 2027, with the lunar surface landing itself still aimed at 2028. A couple of nice personal notes. This will be Andre Douglas' first ever spaceflight after serving as backup crew on Artemis 2. And Luca Parmitano is a fan favorite in Europe.
[00:06:56] Some of you will remember him from a 2013 spacewalk where his helmet began filling with water, a genuinely dangerous moment he handled with real composure. A strong, experienced crew for what NASA itself is calling one of the most complex missions it's ever undertaken. We'll be watching this one closely. Story 4 takes us 57 light years away. To a strange little world astronomers have nicknamed the Pink Planet.
[00:07:23] GJ 504 b was first directly imaged back in 2013 and stood out immediately for its odd magenta color. This week, a Northwestern University-led team using JWST confirmed something theorized about objects like this for 15 years. Its atmosphere is wrapped in salty clouds, unlike anything seen on a substellar object before.
[00:07:48] This is the first direct evidence of salt clouds in the atmosphere of a cold companion object. And GJ-504b earns that description. At around 550 degrees Fahrenheit, it's actually the coldest object of its kind ever directly imaged. And that raises a genuinely open question. Is GJ-504b really a planet, or is its mass actually large enough to make it a brown dwarf?
[00:08:14] The line between giant planet and failed star gets blurry out at the cold end of the scale, and this object sits right on that boundary. Either way, it's a gorgeous demonstration of just how much chemistry JWST can now tease out of worlds we can't visit, can't sample, and can only study through the faintest whispers of infrared light. Salt clouds on an alien world. Try saying that without smiling.
[00:08:40] Next up, Story 5 is an update on a daring rescue mission we first told you about earlier this week, and it's now properly underway. NASA's Neil Jarrell Swift Observatory has been watching gamma ray bursts from orbit since 2004, but its orbit has been decaying faster than expected, thanks to drag from recent high solar activity. And without help, it could re-enter and burn up by later this year.
[00:09:07] The Fix is a robotic servicing spacecraft called Link, built by Catalyst Space Technologies. Designed to rendezvous with Swift, grapple onto fixtures that were only ever meant to be used on the ground before its original 2004 launch, and boost it up to a safer orbit around 600 kilometers high. And here's the fresh development. On Thursday, the 18th of June, Northrop Grumman's Stargazer aircraft,
[00:09:33] the very last flying Lockheed L-1011 TriStar, departed NASA's Wallops Flight Facility in Virginia, carrying Link tucked inside a Pegasus XL rocket. It's now routing via California and Hawaii toward Kwajalein Atoll in the Marshall Islands. Launch is targeted for June 27th. Stargazer will carry Pegasus to around 40,000 feet, drop it, and the rocket will fire Link into orbit in about 10 minutes.
[00:10:03] That's the easy part. The hard part comes after. Link has to chase down and successfully grab a satellite that was never designed to be captured. If it works, it'll be the first time a commercial vehicle has captured an unprepared U.S. government satellite, and the first capture of a science satellite never built for it. High stakes, fast turnaround. This whole mission went from concept to launch pad in under a year. One NASA astrophysics director put it bluntly,
[00:10:33] nobody thought they'd get this far. We'll bring you the result the moment it happens. And our final story of the week takes us to a tiny, strange little asteroid that's been quietly tagging along with Earth for centuries. China's Tianwen-2 spacecraft launched all the way back in May last year on a mission to collect a sample from near-Earth asteroid Kamo Aloha,
[00:10:57] a quasi-satellite only 40 to 100 meters across that loops around the sun in lockstep with our own planet. According to mission design and amateur radio trackers, since China's space agency has gone fairly quiet on official updates, Tianwen-2 completed its orbital insertion at the asteroid on June 7. Since then, observers in Germany using a 20-meter dish have picked up a series of much smaller course correction burns
[00:11:25] between June 11 and 14, almost certainly using the spacecraft's ion engines to fine-tune its position ahead of the main event. That main event, rendezvous and the actual sample collection, is now expected around July 4. Kamo Aloha is scientifically fascinating because some researchers think it may be a fragment blasted off the moon by an ancient impact, though a study published just this month complicates that picture somewhat, based on how its surface has weathered.
[00:11:54] Whatever its true origin, after sample collection, Tianwen-2 will head home with its hull before swinging back out to chase down a comet in the 2030s. A patient, decade-spanning mission finally closing in on its first big milestone. And that wraps up our weekend space and astronomy news wrap. From ancient ocean rocks to record-breaking rockets, a new moon crew, a salty pink world, a daring rescue, and a patient asteroid chase.
[00:12:23] If you enjoyed today's episode, the best thing you can do is share it with a fellow space nerd. And we'll see you back here Monday for more from across the cosmos. I'm Anna. And I'm Avery. Clear skies, everyone.