Space · Friday, 23 October 2026
A NASA safety adviser says a Starship Moon landing may need about 22 launches to fuel it; Musk says 6 to 8
A member of NASA's outside safety panel put the Starship launches needed to fuel one Moon landing at about 22. Elon Musk replied that the real number is 6 to 8. SpaceX's first ship-to-ship refuelling test, planned for early 2027, should narrow the gap.
22
Starship launches one Moon landing may need, by the safety panel's latest estimate
Musk says the real number is 6 to 8
about 3 months
to fill one fuel depot, even at two Starship launches a week
Musk's target is twice-weekly flights in late 2027
2028
the year NASA aims to land astronauts on Artemis IV
it would be the first crewed Moon landing since Apollo 17 in 1972
The lead story — what happened
-
NASA's Aerospace Safety Advisory Panel, a group of outside experts who check the agency's safety, held its quarterly meeting on Thursday.
[1] -
Panel member Charlie Precourt, a former NASA astronaut, said the Moon lander needs many fuelling flights, and the last estimate is around 22.
[1] -
He did not name Starship. But Blue Moon, the other crewed lander NASA has bought, from Blue Origin, does not refuel in orbit on its first missions, so only SpaceX's lander fits.
[1] -
Starship is SpaceX's giant rocket. Its Moon lander cannot get there on one tank, so it must be filled in orbit near Earth with fuel carried up by other Starships.
[1] -
Precourt said Artemis IV, the planned landing, has a large number of firsts that lower its chance of success.
[1] -
Elon Musk, SpaceX's founder, replied on X that 22 is 'way too high' and the real number will be more like 6 to 8.
[1] -
NASA has long declined to give the number. In 2023 its lander chief would not say it, and later put it at 'high single digits to the low double digits'.
[1] -
The count depends on how much super-cold fuel boils away in orbit and how much is lost moving it between ships. Neither has been measured at this size.
[1] [2] -
SpaceX plans its first ship-to-ship refuelling test early in 2027.
[2] -
Musk says Starship could fly every week in the first half of 2027 and twice a week in the second half.
[2] Even at twice a week, filling one fuel depot would take about three months.[1] -
NASA still aims to land astronauts near the Moon's south pole on Artemis IV in early 2028. It has not said which lander will fly.
[3] -
NASA holds an Artemis briefing at 18:00 GMT on Friday, with its administrator Jared Isaacman.
[3]
Who is involved
-
Charlie Precourt
a former NASA astronaut on the Aerospace Safety Advisory Panel, NASA's outside safety advisers; he gave the 22 estimate
-
Elon Musk
founder and boss of SpaceX, which builds Starship; says the true number is 6 to 8
-
Jared Isaacman
NASA's administrator; Precourt praised his push to clear obstacles to the 2028 landing
-
Blue Origin
a US rocket company building Blue Moon, NASA's second crewed Moon lander, which skips refuelling at first
How it unfolded
-
2023 NASA's lander chief declines to give the number
[1] -
Late Sep Starship's 14th test flight mostly goes well
[2] -
Thu 22 Oct the safety panel hears about 22; Musk says 6 to 8
[1] -
Fri 23 Oct NASA's Artemis briefing at 18:00 GMT
[3] -
November Starship's 15th flight, with attempts to catch both stages
[2] -
Early 2027 SpaceX's first ship-to-ship refuelling test
[2]
Where this points
The number will be settled by measurement, not argument: SpaceX's first ship-to-ship refuelling test, planned for early 2027, should show how much fuel is lost in transfer and to boiling.
Signals on this beat
The bar and the word are our reading of how hard each one is pushing, and the arrow is where it is heading.
A US official told the UN that a Russian satellite's close approach looked like a weapons operation.
Europe's Space Rider model crashed when its main parachute came off in a drop test.
Investors put $250m into Xona, a US company building a rival to GPS.
Lasers in a Chinese lab made a tiny flare like those that may heat the Sun's outer layer.
The rest of the day
15 more stories on this beat.
Each with its own sources. None of these is a link to the story above.
-
02
US calls a Russian satellite's approach weapon-like
On Wednesday Brian Hardesty, a US State Department official, told a United Nations committee that Kosmos 2612's moves 'appear consistent with an on-orbit weapons operation'.
[5] Kosmos 2612 is a Russian military satellite.[5] It had moved close to ICEYE-X36, a radar satellite owned by the US arm of ICEYE, a Finnish company whose pictures Ukraine uses.[5] Another US official suggested the gap may have shrunk to about 100 feet, some 30 metres.[5] Konstantin Vorontsov, a Russian diplomat, called the charge 'unfounded' and said all Russian space activity is peaceful.[5] Kosmos 2543 to USA 245, 202030 kmKosmos 2558 to USA 326, 202270 kmKosmos 2612 to ICEYE-X36, 20260.03 kmClosest approaches by Russian inspector satellites, in km. The 2026 bar is about 30 metres, a US official's estimate, too small to see at this scale. Why it matters — In 2022 the same diplomat said commercial satellites helping Ukraine could be a 'legitimate target'.
[5] Earlier Russian inspector satellites came within about 30 to 70 km of US spy satellites, so this approach was far closer, and to a company's satellite.[6] -
03
Ukraine plans satellites it would own
Ukraine's military signed a letter of intent with Nokia, a Finnish telecoms giant, and ICEYE, a Finnish satellite maker, to study a satellite network Ukraine would own.
[7] Ukraine now relies mostly on Starlink and Starshield, SpaceX's satellite internet and its military version.[7] Since 14 October Starshield has limited the speed of terminals on Ukrainian drones, and the limit appears still to be in place.[7] Nokia and ICEYE said on 1 October that they would build such networks for countries.[7] Why it matters — Ukraine did not make the call to slow its links: Musk says the US government sets Starshield's limits.
[7] The letter only commits them to look into it, and names no cost or date.[7] -
04
Europe's reusable spacecraft model crashes
A full-size model of Space Rider, the European Space Agency's planned reusable spacecraft, crashed in a drop test on 6 October, ESA said this week.
[8] It was released from a helicopter about 3 km above a military range in Sardinia.[8] The first small parachute opened, but the large steerable one, called a parafoil, came off as it unfolded.[8] An independent inquiry is looking for the cause.[8] Small parachuteopenedSteerable parafoilcame offTest modelcrashedThe order of the 6 October drop test over Sardinia. One step failing was enough to lose the model. Why it matters — Space Rider is meant to carry experiments to orbit for up to two months and land them on a runway, and the parafoil is what steers it there.
[8] Geraldine Naja, ESA's head of space transport, said the remaining tests are not holding up its first flight, planned for later this decade.[8] -
05
Xona raises $250m for its rival to GPS
Xona Space Systems, a US start-up building a paid alternative to GPS, raised $250m in a round led by Future Ventures, an investment firm.
[9] The deal values Xona at $2.45bn and brings what it has raised since 2019 to over $570m.[9] It plans about 258 satellites, with signals it says are 100 times stronger than today's GPS.[9] It aims to build 50 satellites a year by the end of 2027 and start a timing service next year.[9] Why it matters — Xona's chief executive says governments are interested because jamming near the Strait of Hormuz has disrupted navigation for more than 2,000 ships.
[9] A stronger signal is harder to jam, and next year Xona plans tests with the US Army, Navy and Air Force.[9] -
06
Australia offers ESA its own astronaut
Australia's government has sent the European Space Agency an offer to fly Katherine Bennell-Pegg to the International Space Station on a mission planned for 2028.
[10] She finished astronaut training with ESA in 2024 and would be the first astronaut to fly under Australia's flag.[10] Earlier Australian-born astronauts flew as US citizens on NASA missions.[10] Philanthropists have pledged more than A$6m in cash, and some states have offered support.[10] Why it matters — The flight is expected to cost about A$100m, which the science minister's office once called too much for any government to fund alone.
[10] Australia has already paid A$466,000 for her training.[10] -
07
Spacewalks set to fit new solar wings
Two spacewalks to fit a new roll-out solar array to the International Space Station are planned for 29 October and 5 November, NASASpaceflight reports.
[4] NASA's Anil Menon and Canada's Joshua Kutryk will do the work.[4] The array arrived on a SpaceX cargo Dragon that docked on 15 October with about 2,870 kg of supplies.[4] ESA has also switched off its Fluid Science Laboratory, built to last ten years and run since 2008.[4] Why it matters — The station is due to be retired by the end of 2030.
[4] NASA plans to pick about two companies in spring 2027 to build stations to replace it.[4] -
08
Artemis II crew describe two scares
Speaking at Starmus, a science festival in Tenerife, Artemis II pilot Victor Glover said a cabin-leak warning came about 15 minutes before the engine burn that sent the crew to the Moon on 2 April.
[18] The warning was false, and the burn went ahead.[18] Glover said that if it had come five minutes later, they might not have been able to make the burn.[18] Commander Reid Wiseman said he feared they would never get home when the distance counter rose past its planned top of 219,667 nautical miles.[19] Why it matters — Artemis II was the first crewed trip to the Moon since 1972, and its four astronauts landed safely on 10 April.
[18] [19] Wiseman credited the engineers and flight controllers on Earth for bringing them home.[19] -
09
Exploding stars first helped, then blocked, early light
Astronomers led by Cody Carr of the University of Michigan used the Hubble telescope to study six nearby galaxies that resemble those of the early universe.
[15] They asked how ultraviolet light escaped young galaxies and lit up the gas between them, ending the dark ages after the Big Bang.[15] Winds driven mostly by young stars first cleared paths for the light.[15] Later, supernovae, which are exploding stars, filled those paths with dust and gas that blocked it.[15] The study is in Nature Astronomy.[15] Why it matters — Computer models of the early universe give supernovae a central part in letting that light out.
[15] This result points instead to young stars, which did the work before many supernovae could explode.[15] -
10
Why a fast-feeding black hole still fires jets
Japanese astronomers aimed XRISM, an X-ray space telescope, and several radio telescope networks at 3C 120, a galaxy about 420 million light years away.
[14] Its central black hole swallows gas fast and also fires a jet.[14] Theory said a fast-feeding black hole's thin, cold disc of gas cannot make the magnetic field a jet needs.[14] The team found the thin disc stops about 20 times the black hole's radius out, and a hot, thick flow fills the space inside.[14] Why it matters — It suggests jets always start in a hot inner flow, whatever the outer disc is like.
[14] Jets matter because they can stir up gas and disrupt star formation across whole galaxies.[14] -
11
Lasers make a tiny solar flare in a lab
Researchers at the China Institute of Atomic Energy fired four powerful lasers at a small plastic target to make a 2 mm patch of plasma, a hot gas of charged particles.
[13] When the target's surface was wavy, the plasma's magnetic field suddenly rearranged itself and released a burst called a nanoflare.[13] That plasma reached about 800,000C, nearly twice as hot as with a flat target.[13] The work is in Physical Review Letters.[13] Why it matters — The Sun's outer layer, the corona, is millions of degrees, far hotter than its surface, and nobody is sure why.
[13] Rony Keppens of KU Leuven, a Belgian university, said the result adds one possible cause but does not settle the puzzle.[13] -
12
Stars date van Gogh's The Starry Night
A team led by Elijah Kim, a South Korean astronomer, says the star cluster in van Gogh's The Starry Night is the Hyades, in the constellation Taurus.
[12] By matching the shape of five painted stars, they date the sky to before dawn on 22 July 1889, over Saint-Remy in France.[11] [12] Art historians have dated the painting to mid-June.[12] The paper came out on 22 October in Scientific Reports, a journal.[12] mid-June 1889Art historians' date22 July 1889Sky the team matchedA month separates the date historians give and the sky the team matched. That gap is the dispute the paper opens. Why it matters — In mid-June the Moon would have looked like a lopsided oval, not the thin crescent van Gogh painted, the team says.
[12] Don Olson, a Texas astronomer who studies skies in art, says Venus is in the wrong place for their date.[12] -
13
Venus passes between Earth and Sun
Venus passes between Earth and the Sun at 04:00 UT on Saturday 24 October, an event called inferior conjunction.
[17] It will be about 40 million km from Earth and only 6 degrees from the Sun in the sky, so it is very hard to see safely.[17] SOHO, a spacecraft that watches the Sun, can see Venus in one of its cameras from 21 to 28 October.[17] After that, Venus moves into the dawn sky.[17] Why it matters — This is when Venus comes closest to Earth on its loop.
[17] Its tilted path keeps it from crossing the Sun's face this time, and the next such crossing is in 2117.[17] -
14
Rubin's test camera shows the Seagull Nebula
The Vera C. Rubin Observatory has released a new picture taken by its test camera, called ComCam, to mark two years since testing began.
[16] It shows part of the Seagull Nebula, a cloud where stars are forming, about 3,700 light years away.[16] ComCam took about 16,000 pictures in seven weeks in late 2024.[16] It is a smaller version of the observatory's main camera, the largest digital camera ever built.[16] Why it matters — ComCam's 144-megapixel pictures went through the same processing the main camera will use, so they test the whole system.
[16] -
15
Trump says Musk restored Ukraine's Starlink
On Thursday Donald Trump, the US president, said Elon Musk had restored Ukraine's access to Starlink, SpaceX's satellite internet.
[20] 'Bottom line, he put it back,' Trump said, without saying whether he had phoned Musk.[20] The Wall Street Journal reported that Trump asked Musk to lift the limits, and that Starshield, the military version, worked more normally soon after the call.[21] Earlier that day Ukraine's President Volodymyr Zelensky said its speed limit had still not gone back up to 400 km/h.[20] Why it matters — A senior European official told the Associated Press that nothing had changed in how Starshield works.
[22] Who ordered the slowdown is still disputed: Musk says the US government sets Starshield's limits, and Trump says he was not involved.[22] [21] -
16
Mars Express to watch Japan's Phobos probe
JAXA, Japan's space agency, said on 21 October that MMX, its probe to Phobos, a moon of Mars, had opened its solar panels and finished its first critical steps after launch.
[23] MMX is due at Mars in 2027 and plans to bring about 10 g of Phobos soil to Earth in 2031.[23] Mars Express, a European orbiter circling Mars since 2003, will photograph MMX's landing site, a former team member told The Register.[23] Its mission now runs to 2029.[23] Why it matters — An orbiter already at Mars can look over ground that the new probe reaches only in 2027.
[23] Mars Express may also help Europe's Rosalind Franklin rover, now due to launch in 2028.[23]
Why a plan made of many steps that each usually work can still often fail
When every step has to work for the whole plan to work, each small chance of failure adds to the rest, so long chains go wrong far more often than any one step.
The twist
Imagine a step that works 97 times in 100 sounds safe. Chain 22 of them together and all 22 work only about half the time.
The picture
How it works
- A big job is a chain of steps
- Every step must work for the job to work
- Each step has a small chance of going wrong
- Those small chances add up as steps are added
- So a long chain fails far more often than any one step
The same force, elsewhere today
Where this chain is also running, in today's other stories.
-
Space Rider's crashed test model
The small parachute opened as planned, but the steerable parafoil came off, and that one failed step lost the whole model.
-
Artemis II's false leak warning
The burn to the Moon could go only if nothing was wrong, and one false cabin-leak warning 15 minutes out nearly called off the trip.
-
Australia's astronaut offer
The flight needs ESA to accept, about A$100m to be found and a place on a 2028 mission, and a gap in any one stops it.
Where you've seen this
Connecting flights
three connections that each run on time most days still leave many trips arriving late
Factory checks
a phone that must pass fifty tests fails if any single test fails
A school play
every actor must turn up, and one sick child stops a scene
The catch
It only holds when one failed step ruins the whole job. A tanker flight that fails can often be replaced by another, which costs time rather than the landing.
And the whole of it
Each team on Artemis tests its own step: SpaceX its tankers, Blue Origin its lander, NASA its capsule. No one team sees the odds for the whole trip, which is why NASA keeps a panel whose job is to add them up.
What is really going on
A member of NASA's own safety panel says a Starship Moon landing may need about 22 fuel launches, and Elon Musk says 6 to 8.
Why it works on us — A confident number from the person building the rocket sounds like a measurement, but it is an estimate that no test has checked yet.
Who gains
-
Blue Origin
— NASA has not picked which lander flies first, and Blue Moon does not need refuelling in orbit on its first missions, so a high Starship count helps its case.
[1] [3] -
Nokia and ICEYE
— Ukraine's letter of intent makes them the first partners for a network Ukraine would own, three weeks after they launched that offer.
[7] -
Xona and its investors
— Jamming near Hormuz has raised government interest in a stronger navigation signal, and the new round values Xona at $2.45bn.
[9] -
Australia's space companies
— The flight is pitched as a full Australian mission carrying locally made experiments and technology.
[10]
Who pays
-
The future Artemis IV crew
— Every extra fuel launch is one more step that must work before they leave Earth.
[1] -
ICEYE US
— Its satellite was approached to within tens of metres, by a country whose diplomat has called such satellites possible targets.
[5] -
Ukraine's drone units
— Their Starshield links have been slowed since 14 October, and the limit appears still to be in place.
[7] -
ESA's Space Rider team
— It lost a full-size test model and must wait on the inquiry before the next drop.
[8]
What nobody knows yet
Open questions from across today’s stories — ours included.
-
01
How many Starship launches one Moon landing really needs.
The safety panel's figure is about 22 and Musk's is 6 to 8.
[1] Both depend on how much fuel boils off and leaks in transfer, which has not been measured at this size.[1] [2] -
02
What NASA says at Friday's Artemis briefing.
It starts at 18:00 GMT, after this edition, and is due to cover Artemis III and the 2028 landing plan.
[3] -
03
Which lander will carry the first Artemis crew to the surface.
NASA says it depends on how each lander's development goes and on Artemis III in 2027.
[3] -
04
How close Kosmos 2612 actually came to ICEYE-X36.
LeoLabs, a tracking company, said within 500 metres and likely closer, and a US official suggested about 100 feet. Satellite tracking cannot pin it down.
[5] -
05
Whether the Russian satellite will move in again.
It backed away, but its path does not rule out another approach, and Russia has not explained the first one.
[5] -
06
Why Space Rider's parafoil came off.
An independent investigation is still running, and ESA has not said what it has found.
[8] -
07
Whether Ukraine will build its own satellite network, and when.
The letter of intent only starts a study, and no budget or date has been given.
[7] -
08
Whether Australia can pay for its astronaut's flight.
Supporters put the cost at about A$100m. Philanthropists have pledged more than A$6m, and some states have offered only indicative support.
[10] -
09
When The Starry Night was really painted.
Kim's team matches the sky to 22 July 1889. Don Olson says Venus does not fit, and van Gogh wrote of a new starry study on 18 June.
[12]
Australia's government has offered the European Space Agency a 2028 space station flight for Katherine Bennell-Pegg, who would be the first astronaut to fly under Australia's flag. Philanthropists have already pledged more than A$6m in cash towards it.
Also true today
- Researchers at the China Institute of Atomic Energy made a tiny solar flare in a lab for the first time, using four lasers and a speck of plastic. Their plasma reached about 800,000C, nearly double the run without one.
- A team led by Elijah Kim matched five stars in van Gogh's The Starry Night to the Hyades, a star cluster, as it stood before dawn on 22 July 1889.
More from Space
Across the beats