Space, in brief

Troy Meink, the US Secretary of the Air Force, said on Monday that the United States now has on-orbit weapons that can defend its forces against attack. [2]

It is the first time the US has said in public that it has put an offensive weapon in space. [3]

Meink gave no details at all: not what the weapons are, not when they went into orbit, not whether they have ever been tested. [2]

He said the silence is deliberate. Saying that the weapons exist helps deterrence, he said, and describing them would not. [2]

A day later, General Douglas Schiess, the head of US Space Force operations, repeated it from the stage at the same conference in Maryland. [1]

Schiess told the story of one Space Force operator under missile fire who, in his words, locked onto a target and waged electromagnetic warfare. [1]

That phrase points at jamming a satellite's radio link rather than hitting it. Bleddyn Bowen, who studies military space at Durham University in Britain, told the BBC he expects a jammer too. [1][5]

A 1967 treaty bans weapons of mass destruction in orbit. It says nothing about any other kind, and the US, Russia and China have all worked inside that gap. [3]

A US Space Force spokesperson said its work in orbit now covers disruption, degradation and destruction of a rival's capabilities, for attack as well as defence. [3]

US officials accused Russia in 2024 of putting working anti-satellite weapons in orbit, and say Chinese satellites regularly manoeuvre close to American ones. [2]

Richard Palmer, a director at US Space Command, called the admission a landmark on Tuesday at a defence conference in Paris, and also declined to describe the weapons. [4]

Germany has a 35-billion-euro military space plan. Major General Michael Traut, who runs German Space Command, says Germany will not field destructive weapons in orbit but will fund jammers and lasers. [4]

Why it matters. Watch whether Russia or China answers with a claim of its own, because an announcement with no evidence attached only does its work if rivals believe it.

SpaceX was scheduled to launch a second classified US Space Force mission in five days on Tuesday night, from Vandenberg Space Force Base in California. [6] The mission is called USSF-259. The first, USSF-153, left the same base on 10 September. [6] Neither payload has been described. The live broadcast was expected to stop shortly after the rocket's first stage landed on a ship at sea, about eight and a half minutes in. [6] It was to be SpaceX's 110th launch of 2026, and the thirteenth landing for that particular booster. [6]

Why it matters. The flight is public and the cargo is not, which is the same split the two officials made at the conference this week. Anyone can count American military launches; nobody outside the US government can say what they carry.

Two spacecraft owned by Impulse Space, a Californian company, flew within 200 metres of each other in low Earth orbit and took photographs of the approach. [7] Both are called Mira. They are orbital transfer vehicles: dishwasher-sized tugs that carry up to 300 kilograms of somebody else's equipment from wherever a rocket drops it to the exact orbit the customer wanted. [7] The two launched separately, in January and November 2025, and the company announced the meeting on 8 September. [7]

Why it matters. Flying up to another object in orbit is the same skill whether the aim is to repair it, refuel it or interfere with it. Impulse sells that skill, and the photographs are how it shows customers what its tugs can do.

The European Space Agency published its 2026 Space Environment Report, the count it has made every year since 2017. [8] More than 300 launches in 2025 put over 4,000 new payloads up, about ten a day. [8] Just over three dead satellites or rocket stages came down each day. [8] ESA's single-number measure of whether current behaviour is sustainable in the long run got about ten times worse in one year. [8] A new measure this year covers the chance that a surviving fragment injures somebody on the ground. [8]

Why it matters. ESA now says that clearing up existing junk is required, not optional, because debris collides and makes more debris. It has cut its projection window from 200 years to 100 and the numbers still come out higher than last year's did. [8]

Martin Elvis and Jonathan McDowell, two astronomers at the Center for Astrophysics, Harvard and Smithsonian, worked out how long a settlement could live off the Moon's ice. [9] The ice sits in polar craters that have had no sunlight for four billion years. [9] They assumed a generous billion tonnes of it and 98% recycling, the rate the space station manages. [9] On those figures a million-person city runs dry in just over a century. [9] Best estimates of lunar ice are about 30 times smaller, which brings that down to roughly a decade. [9]

Why it matters. A village of a thousand people, or a town of ten thousand, would last centuries on the same ice, so the finding is about size rather than about going at all. Elvis writes that surveys only reach a few metres down, and the rubble layer goes tens of metres, so the first job for anyone planning bigger is to look deeper. [9]

Astronauts printed cartilage tissue aboard the International Space Station on Tuesday. [10] Jessica Meir of NASA and Sophie Adenot of the European Space Agency took cartilage cells out of a research fridge called MERLIN. [10] They loaded them into a printer called Auxilium, inside a sealed glovebox in the Japanese laboratory module. [10] NASA says cartilage printed in weightlessness comes out better than cartilage printed on Earth. [10] The sessions can be run remotely from the ground. [10]

Why it matters. Damaged cartilage does not heal well, and the aim of this work is implants grown from a patient's own cells. That is a result for people who will never leave the ground. [10]

NASA said on 15 September that Mike Lippert, the newest test pilot on its X-59 aeroplane, ran its engines on the ground for the first time. [11] The X-59 is shaped so that flying faster than sound makes a soft thump instead of a bang. [11] NASA plans to fly it over American towns and ask people what they heard. [11] The answers go to the regulators who currently forbid supersonic flight over land. [11] The two established X-59 pilots, Nils Larson and Jim Less, coached Lippert through the run. [11]

Why it matters. A third trained pilot is what keeps a flight-test programme moving when one person is unavailable. The rule the survey is aimed at was written around the old, loud sonic boom. [11]

NASA's Human Research Program picked ten winning entries in a public competition about a problem it cannot design away. [12] Artemis II carried four astronauts, each measured on hundreds of body readings over time. [12] That is a huge number of measurements from a tiny number of people, which ordinary statistics handles badly. [12] The contest asked anyone at all for methods that draw trustworthy conclusions from data shaped like that. [12] First place went to Praniil Nagaraj, whose entry treats four astronauts as a detailed case series rather than a failed population study. [12]

Why it matters. Every crewed flight has this problem and it gets sharper as missions get longer while crews stay tiny. NASA put the question outside its own building instead of solving it in-house. [12]

NASA astronaut Jessica Meir photographed the aurora from the International Space Station on 7 September and posted one of the pictures the next day. [13] The station was 411 kilometres up and over Kyrgyzstan at the time. [13] Stacking several frames produced a long exposure in which the green glow sits among star trails, moonlight, passing satellites and city lights. [13] The US weather agency NOAA traced the display to a fast stream of solar wind out of a hole in the Sun's atmosphere, plus the tail end of several earlier eruptions. [13]

Why it matters. The colour depends on which gas the incoming particles hit and how high up. Oxygen glows green between about 100 and 200 kilometres and red above that, and the purple Meir saw is those colours mixing. [13]

International Observe the Moon Night falls on Saturday 19 September. [14] The date is picked for the first quarter moon, when the Moon is up in the late afternoon and evening. [14] At that phase the line between lunar day and night runs across the middle of the disc, the Sun sits low along it, and craters and mountains throw long shadows. [14] NASA keeps a map of hundreds of registered events, from star parties run by local astronomy clubs to online sessions hosted by observatories, and anyone can register one of their own. [14]

Why it matters. Nothing is required to take part. The Moon at first quarter is the one target in the sky that rewards a pair of binoculars as much as a telescope. [14]