Space, in brief

Satellites ordered in rounds

L3Harris finished the design of its third batch of missile-tracking satellites while its first full batch has still not launched. [5] SpaceX is due to fly a third batch of secret Starshield satellites for the US Space Force on Saturday. [8] Starfish flew two test craft before selling its first working one. [6]

Buying companies instead of building

Iridium's shareholders voted 99.6% to be bought by Rocket Lab, whose finance chief says more purchases are coming. [4] NASA is paying Starfish $15m to inspect dead satellites rather than building an inspector itself. [6]

Old observations paying off

XRISM watched a neutron star for 16 hours in February 2025, and the result came out last week. [10] Perseverance has been reading rocks at the edge of Jezero crater since 2023, and the paper appeared on 21 September. [9] The black-hole study reused telescope data on 20 past events. [11]

NASA's money on a few big bets

PRIMA is capped at $1.2bn and is the first of a new class of billion-dollar missions. [1] Jared Isaacman says he is aiming NASA at a few near-impossible missions. [7]

1. 1NASA picks PRIMA, a far-infrared telescope, as the first of a new class of billion-dollar missions. It launches in 2033.
2. 2Iridium's owners vote to sell to Rocket Lab
3. 3L3Harris finishes its third round of missile-tracking satellites
4. 4Starfish's satellite inspector gets its first paid job
5. 5NASA promises a Moon timing update in October

NASA said on Wednesday 23 September that PRIMA, a far-infrared space telescope, moves into its next design stage, called Phase B. [1]

Watch whether PRIMA clears its Phase C review with the $1.2bn cap intact - that review is the first real test of NASA's new mission class.

Shareholders of Iridium, one of the biggest satellite-communications companies, voted on 24 September to accept a buyout by the rocket maker Rocket Lab, with 99.6% in favour. [4]

The deal pays about $54 a share in cash and Rocket Lab stock and should close in mid-2027. [4]

Rocket Lab's finance chief Adam Spice said the company is looking at buying more firms. [4]

He said 40 to 50% of what its satellite business can do came from companies it bought. [4]

Rocket Lab is turning itself into a company that sells satellites, sensors and communications, not just launches, because Spice says government buyers want more than one thing from a supplier. [4]

L3Harris, a US defence electronics company, said on 24 September it has finished the baseline design for 18 satellites in the third round of the US military's missile-warning network. [5]

The buyer, the Space Development Agency, orders satellites in rounds called tranches and aims to put new ones in orbit every two to three years. [5]

L3Harris has contracts for 74 of these satellites: four prototypes launched in 2024, 36 in production, and these 18. [5]

Its first full round could start launching by December, though early spring is more likely. [5]

Each round is a chance to change the design: L3Harris made only small changes between its first and second rounds, and major changes to the sensors for the third. [5]

Order a small batch, fly it, fix what went wrong, then order the next. A fault found in orbit is then fixed in a few satellites, not in seventy.

L3Harris finished its third design before its first full round had launched, so what orbit teaches is not in it yet.

The buyer sees only the round they bought, and the faults of the round before it were fixed by someone they will never meet.

Starfish Space, a US company, said on 24 September that its first working Otter spacecraft will launch next month on a SpaceX rideshare flight. [6]

Otter's first job is a $15m NASA mission: it will fly to within a few hundred metres of several dead US satellites and record how they spin and what state their surfaces are in. [6]

Starfish flew two smaller test craft first, in 2023 and 2025. [6]

The US military has bought an Otter for $37.5m, and the Space Development Agency is paying $52.5m for Otters to remove dead satellites from 2027. [6]

A craft that can fly up to another satellite is the first step to removing dead ones, and the customers already waiting are the US military. [6]

Jared Isaacman, the head of NASA, said on 23 September that the agency will give an update early next month on when its Artemis missions will return people to the Moon. [7]

He said the update might coincide with the next space station crew's launch. [7]

He said China's plans gave NASA its urgency this year, and the race is decided by whose flag is on the suit of the next person down the ladder. [7]

Whether a Moon base gets built under him is luck, he said, depending on policy, Congress and budget. [7]

Isaacman said a landing needs many ingredients to come together, and the October update is where NASA will say how many are in place. [7]

SpaceX is due to launch a classified mission called USSF-385 for the US Space Force before dawn on Saturday 26 September from Vandenberg in California. [8]

It is thought to be the third flight in a series carrying Starshield satellites, a version of SpaceX's Starlink internet satellites built for government use. [8]

The Space Force gave no details of the first two flights, on 15 August and 10 September, but catalogued 23 new satellites in orbit after each. [8]

The US military is building its own version of Starlink one batch at a time, and each batch adds about 23 satellites. [8]

NASA's Perseverance rover found that water passed through rocks at the edge of Mars's Jezero crater at least three separate times, and once it was hot. [9]

The study, published on 21 September, used the rover's SuperCam instrument on more than 185 patches of bedrock in an area called the Margin Unit. [9]

Cold groundwater made carbonate minerals first, the ancient lake added silica later, and veins of calcium sulfate and fluorite show hot water came last. [9]

The team cannot yet say when each episode happened. [9]

On Earth, hot underground water supports microbes, so this corner of Mars is a place that might once have supported life. [9]

Astronomers using XRISM, an X-ray telescope in orbit, watched gas from a huge star fall onto a neutron star called GX 301-2, about 13,000 light-years away. [10]

A neutron star is what is left when a big star dies: one to two times the Sun's mass squeezed into a ball about 20 km wide. [10]

XRISM watched for 16 hours in February 2025 and clocked the stream hitting the neutron star at 540,000 km per hour. [10]

The result was published on 18 September in Science Advances. [10]

Nobody had clearly seen gas from a star's wind falling onto a neutron star before, and that is the step that makes these systems flare in X-rays. [10]

Two astronomers found that black holes launch their jets at the same point whether they weigh a few Suns or a billion. [11]

They studied 20 events in which a black hole tore a star apart, and could model ten of them. [11]

Jets came in two phases: one while the black hole was feeding fastest, and a second months or years later. [11]

The second came once feeding fell to 2% of the rate at which the black hole's own light pushes food away, the same mark at which small black holes fire jets. [11]

Astronomers can now roughly predict when a black hole that has eaten a star will fire its jet, and those jets shape whole galaxies. [11]

Neutrinos, particles that pass through almost everything, may decide whether a dying star explodes or quietly collapses into a black hole, a study in Physical Review D says. [12]

Two physicists at the Niels Bohr Institute in Copenhagen simulated the collapse of 195 stars of nine to 120 times the Sun's mass. [12]

When they let the neutrinos switch between their three kinds, more stars failed to explode, especially those of 16 to 30 solar masses. [12]

That could explain why astronomers see fewer supernovas than predicted. [12]

Which stars explode decides how much of the material that planets and people are made of gets scattered into space. [12]

Researchers at the University of Nottingham cut Earth's magnetic field to near zero around fruit flies for 70 days. [13]

Flies carrying a Parkinson's-linked gene fault lived about 20% longer but climbed worse; healthy flies lived shorter lives and climbed better. [13]

The team traced the effect to Complex II, part of the machinery in cells that makes energy. [13]

The researchers say astronauts on long Moon and Mars trips will be outside Earth's field, and nobody knows what that does to the body apart from the radiation. [13]

Every person so far has lived inside Earth's magnetic field, and a Mars crew will be the first to leave it for a long stretch. [13]

Ethereal Space, a Denver company, said on 23 September it won a $27.4m, 24-month task order under a programme run by NOAA, the US weather agency, to buy observations from private satellites. [14]

Its satellites read the atmosphere by watching navigation-satellite signals bend through it, gauge the thin air at satellite heights, and take pictures in visible and infrared light. [14]

First data is due on 1 December 2026. [14] Its chief executive called it the move from demonstrating new sensors to delivering data at scale. [14]

A weather agency buying readings from a start-up's satellites means the forecast can improve without the agency building the satellite itself. [14]

A Landsat 8 image from 30 August shows the Murchison region of Western Australia, normally dry shrubland, carpeted in wildflowers. [15]

Rain above average in June and August, plus several cold fronts, woke seeds that can lie dormant for years. [15]

Local experts think it may be the best bloom there in almost 20 years, and some threatened plant species appeared among the flowers. [15]

The flowers also covered the ground at the CSIRO Murchison Radio-astronomy Observatory, whose antennas study the southern sky. [15]

A satellite that photographs the same ground year after year is what makes this year's bloom measurable against last year's. [15]

Rocket Lab was set to launch its 96th mission overnight, an Electron rocket from New Zealand carrying a Strix radar satellite for the Japanese company Synspective. [16]

Lift-off was scheduled for 00:15 GMT on 26 September. [16]

It is the 13th Strix satellite Rocket Lab has carried; Synspective's radar satellites collect images for city planning, infrastructure and disaster response. [16]

It is Rocket Lab's 18th launch of 2026, the 15th by Electron, with three by its suborbital HASTE rocket. [16]

Synspective has bought thirteen rides on the same rocket, which is the kind of repeat customer a small launcher needs. [16]

Neptune, the outermost planet, reached opposition at about 01:00 GMT on 26 September, meaning it rises as the Sun sets and stays up all night. [17]

It was closest to Earth on 25 September, at just over 4.3 billion km, about four light-hours away. [17]

At magnitude 7.6 it is too faint for the naked eye, and shows as a tiny grey-blue dot in a telescope. [17]

The Harvest Moon sat near it in the constellation Pisces that night. [17] Neptune takes 165 years to go round the Sun. [17]

This year Neptune sits almost on the celestial equator, so observers in both hemispheres get an equal view. [17]