Space

Of all the asteroids that have imperiled the planet, 2024 YR4 is unparalleled. Soon after it was spotted in December 2024, worldwide telescopic observations quickly positioned it as the most dangerous space rock ever discovered—one that stood a 3.1 percent (or 1-in-32) chance of crashing into Earth on December 22, 2032. If it were to hit one of the cities potentially in its path, this 60-meter asteroid would have unleashed a force comparable to several atomic bombs, devastating the unfortunate metropolis.

An Earth impact was eventually ruled out in February of last year. But a late plot twist revealed 2024 YR4 stood a 4.3 percent (1-in-23) chance of slamming into our moon on the same date. Now a concerted effort by astronomers indicates the asteroid will comfortably miss our alabaster companion, too—by 21,200 kilometers.

“We think this is certainly the faintest solar system object that has ever been observed,” says Andy Rivkin, an astronomer and planetary defense researcher at Johns Hopkins Applied Physics Laboratory in Maryland, who led the JWST effort to track 2024 YR4.

NASA has selected United Launch Alliance's Centaur V upper stage for the Artemis missions that aim to return astronauts to the lunar surface for the first time since 1972.

The space agency will use the Centaur V, currently flying as the upper stage of ULA's Vulcan rocket, for Artemis IV and V, both slated for 2028. A flight spare is also being ordered.

The Interim Cryogenic Propulsion System (ICPS) currently used by Artemis is a modified Delta IV cryogenic second stage, always intended as a stopgap. NASA had planned to replace it with the more powerful Exploration Upper Stage (EUS) but that program is running behind schedule and over budget. When new administrator Jared Isaacman signalled plans to increase SLS flight cadence, the writing was on the wall leaving Centaur V to fill the gap.

ULA is not the only upper stage option, and NASA's intention to issue a sole-source contract might surprise some. However, the agency noted that alternatives, such as Blue Origin's New Glenn Upper Stage (NGUS), require "significant modifications" to Mobile Launcher 1, and ULA was already familiar with the steps needed to modify an upper stage for SLS. In addition, the Centaur V is a variant of the Atlas Centaur, used under the Commercial Crew Program, meaning that qualifying the stage for a human crew should not cause too many concerns.

The NASA Authorization Act of 2026 has been approved, and alongside a directive for NASA to establish a permanent Moon base, the legislation includes language extending the International Space Station to 2032.

The ISS project was set to end in 2030. In 2024, NASA awarded a contract to Elon Musk's SpaceX to build a tug to de-orbit the outpost by 2030, assuming it lasts that long. By then the complex's first module will have been in orbit for more than 30 years, and cracks have plagued the structure alongside hardware failures as the laboratory ages. One space agency insider observed that "it's on its last legs."

Then again, in a 2024 interview with The Register, ESA astronaut Andreas Mogensen said of the ISS: "I wouldn't be surprised if we extended it a few years."

NASA is to begin soliciting proposals for two commercial space stations immediately (Axiom Space and Vast spring to mind), but, mindful of a potential gap, lawmakers have also directed the agency to keep the ISS running for a few more years – certainly until at least one commercial station is launched and capable of taking over ISS operations.

In the beginning, the Bible tells us,

God divided the light from the darkness.

And God called the light day, and the darkness He called night.

And so it has been ever since — until now.

Here in the 21st century, we humans are on the cusp of turning night into day — and bidding good night to the stars that have guided us home for thousands of years.

Two little-noted applications under review by the Federal Communications Commission would, if fully implemented, fundamentally remake the night sky. But the FCC, the satellite regulator, appears to have fast-tracked approval without much of a pause to weigh the benefits of these proposals against the harms they could cause to life on the planet.

A start-up called Reflect Orbital proposes to use large, mirrored satellites to redirect sunlight to Earth at night, with plans to bathe solar farms, industrial sites and even entire cities in light that could, if desired, reach the intensity of daylight. At the same time, Elon Musk’s SpaceX wants to launch as many as a million satellites to serve as orbiting data centers — 70 times the number of satellites now in orbit. We could have a million points of light streaking across our skies at night.

If at first you don't succeed, move, move the goalposts.

Nasa announced on Friday radical changes to its delayed Artemis III mission to land humans back on the moon, as the US space agency grapples with technical glitches and criticism that it is trying to do too much too soon.

The abrupt shift in strategy was laid out by the space agency’s recently confirmed administrator, Jared Isaacman. Announcing the changes on Friday, he said that Nasa would introduce at least one new moon flight before attempting to put humans back on the lunar surface for the first time in more than half a century, in 2028.

The new, more incremental approach would give the Nasa team a chance to test flight and refine its technology. As part of the changes, the Artemis II mission to fly humans around the moon this year, without landing, would also be pushed back from its latest scheduled launch on 6 March to 1 April at the earliest.

“Everybody agrees this is the only way forward,” Isaacman told reporters at a news conference. “I know this is how Nasa changed the world, and this is how Nasa is going to do it again.”

The US space agency has released a “pre-solicitation” for what is expected to be a hotly contested contract to develop a spacecraft to orbit Mars and relay communications from the red planet back to Earth.

Ars covered the intrigue surrounding the spacecraft in late January, which was initiated by US Senator Ted Cruz, R-Texas, as part of the “One Big Beautiful Bill” legislation in the summer of 2025. The bill provided $700 million for NASA to develop the orbiter and specified funding had to be awarded “not later than fiscal year 2026,” which ends September 30, 2026. This legislation was seemingly crafted by Cruz’s office to favor a single contractor, Rocket Lab. However, multiple sources have told Ars it was poorly written and therefore the competition is more open than intended.

The pre-solicitation released this week is not a request for proposals from industry—it states that a draft Request for Proposals is forthcoming. Rather, it seeks feedback from industry and interested stakeholders about an “objectives and requirements” document that outlines the goals of the Mars mission.

A hilly landscape that looks like spiderwebs when viewed from orbit holds clues to the history of water on ancient Mars.

(I hope this link works, unlike the last one...)

An ancient, fast-feeding quasar is breaking the rules of how black holes consume matter and generate galaxy-shaping jets.

To boldly go where no man has gone before

Nearly three years ago, a particle from space slammed into the Mediterranean Sea and lit up the partially complete Cubic Kilometer Neutrino Telescope (KM3NET) detector off the coast of Sicily. The particle was a neutrino, a fundamental component of matter commonly known for its ability to slip through other matter unnoticed.

The IceCube observatory in Antarctica, a comparable detector that has been running for more than a decade, has found hundreds of cosmic neutrinos — but none quite like this one. Some 35 times more energetic than any neutrino seen before, the particle might have shot out from a highly active galaxy — a blazar — or a background source (opens a new tab) of cosmogenic high-energy particles that scientists suspect pervade the cosmos.

But those aren’t the only possibilities. The day after the KM3NET collaboration announced the detection (opens a new tab), the physicist David Kaiser (opens a new tab) walked into a room full of his colleagues at the Massachusetts Institute of Technology with a bold proposition: What if the monster neutrino came from an exploding primordial black hole?

Such black holes “could form before there were even atoms, let alone stars,” said Kaiser, who has been heavily involved in the hunt for these hypothetical objects.

The idea that the neutrino came from a primordial black hole is a long shot; Kaiser said he was “half-joking” when he suggested it. But in the absence of a definitive explanation, it remains intriguing, not least because the existence of primordial black holes could mean they play a role in dark matter.

So the question is, did we just spot one?

As we prepare for missions beyond Earth orbit, one crucial challenge remains: keeping astronauts healthy in microgravity. Without daily exercise, their muscles, bones and cardiovascular systems weaken, which could impact mission success and astronaut safety, especially in destinations such as the moon or Mars, where crew will have to operate autonomously immediately after landing.

This is why ESA has developed the European Enhanced Exploration Exercise Device (E4D)—a compact, versatile in-flight exercise system designed to ensure astronauts stay strong and ready for the physical demands of returning to Earth or working on other planetary surfaces.

E4D combines four exercise modes: resistive training, cycling, rowing and rope pulling, offering a wide range of workouts and the flexibility to add new ones later.

"E4D is a gamechanger for astronaut health. By enabling a broader and more adaptable range of resistance exercises, it supports the preservation of muscle mass and bone integrity in microgravity, which are two of the biggest physiological challenges during long‑duration missions," says ESA's E4D principal investigator Tobias Weber.

"Just as important is E4D's self‑monitoring capability. Using an integrated camera-based motion capture system, it allows astronauts to track their performance, evaluate their movement execution and self‑correct posture in real time. This reduces reliance on ground supervision and helps ensure that every training session remains safe, precise and effective, even in the demanding environment of orbit," adds Jennifer Struble, ESA's Operations Team Lead for E4D and Co-Investigator.

"E4D is a system I'm really looking forward to using during the εpsilon mission. I really enjoy exercising for both physical and mental well-being and since it's especially important to protect our bones and muscles in microgravity, I'm excited to try the new workouts made possible in space thanks to this European technology," says ESA astronaut Sophie Adenot, who is now practicing with E4D on the ground as part of her mission preparations.

More in the article. I've also crossposted this to mander.xyz/c/space.