by Duncan Lunan

As anticipated, Comet 3I/ATLAS continues to make headlines as it nears its closest approach to Earth on December 19^th.  It will then be ‘only’ 269 million km away, so if images of it don’t get much sharper, conspiracy theorists will doubtless continue to insist that they must be faked, followed by the usual mantra, ‘Why is NASA lying to us?’  Nevertheless there have been some interesting new developments, so more on that below. 

Meanwhile in the gap between the successful launch of Starship/Superheavy Flight 11 and the debut of new models of both next spring, there has been a less welcome event.  During a pressure test on November 21^st, the lower oxygen tank of Booster 18 burst, spilling cryogenic fluid, though the Superheavy remained upright  (Figs. 1 & 2). 

The upper methane tank was empty so there was no explosion, and no damage to the test site.  As SpaceX has both Starships and Superheavies in mass production, the event is not expected to produce a major delay to the programme, unless major changes to the third version of the Superheavy turn out to be needed.

Meanwhile, as the recovered first stage of the second New Glenn booster reached port  (Figs. 3 & 4), surprisingly undamaged compared to the Starship ocean splashdowns  (Fig. 5), though it hadn’t undergone a full orbital re-entry – Blue Origin has announced major upgrades to be made progressively through the next two launches, upgrading the thrust of the first and second stage engines, the number of BE-4 engines on the first stage from 7 to 9  (Fig. 6), and the number of second stage engines from 2 to 4, so the vehicle is designated NG-9-4. 

The changes will bring the capability of the vehicle to 70 tonnes in Low Earth Orbit, 14 tonnes to geosynchronous orbit, and 20 tonnes to trans-lunar orbit, (Mel Trivalo, ‘Blue Origin Announces New Glenn Roadmap: Engine, Vehicle Upgrades and New Glenn 9×4’, EONMSK NEWS, November 20^th 2025), giving it a payload range roughly equivalent to the SpaceX Falcon Heavy, though it will be taller than the Saturn V used for the Apollo Moon landings  (Fig. 7). 

Although Blue Origin may fly a Mark 1 version of its lunar lander on the next New Glenn, cargo deliveries to the lunar surface are not expected until 2028, with crewed flights to come later. 

However the proposed Artemis 3 crewed landing with a modified Starship vehicle  (Fig. 8)  has slipped to 2027, and with further delays possible, the Acting NASA Director Sean Duffy had issued a call for alternative delivery methods.  In a total volte-face from his previous stance, President Trump has decided that he wants ‘dyed-in-the-wool Democrat’ Jared Isaacman for Director after all, and the relevant Congressional and Senate hearings are already taking place.  Some US politicians had previously questioned whether Isaacman wasn’t too closely linked to SpaceX, on whose Dragon capsule he has already flown  (Fig. 9), and it remains to be seen whether the enquiry proposed by Duffy will go ahead. 

But if the Artemis 3 crew transfer from the Orion capsule to a Blue Origin lander instead of a Starship, it will strengthen the case for the transfer and return to take place at the Lunar Gateway space station (Fig. 10), currently threatened with cancellation, rather than in free orbit with the Orion unoccupied  (Fig. 11).

Meanwhile the Artemis II mission, intended to be the first human flight to the Moon since December 1972, is fully stacked in the Vehicle Assembly Building at Kennedy Space Centre  (Fig. 12)  and ready for a full dress rehearsal, before rolling it out for launch in early February. 

As I write a joint Russian-American crew has just docked with the International Space Station, in a Soyuz spacecraft  (Fig. 13);  China has sent up Shenzhou-22 to the Tiangong-2 station  (Figs. 14 & 15), ending the temporary isolation of the Shenzhou-21 crew after their return vehicle was used to bring back the Shenzhou-20 crew, whose spacecraft had experienced a debris strike on a window;  and the next flight of the Boeing Starliner to the ISS, next year, will be an uncrewed cargo mission before that programme gets back on schedule.

When the launch of the twin ESCAPADE Mars probes on New Glenn 2 was first postponed to February 2025, it was announced that the booster was powerful enough to send them later than the planned launch window.  Because it’s been postponed till now, they have instead been parked in a temporary orbit around the Sun-Earth L2 point, sharing it with the James Webb Space Telescope  (Fig. 16), though the area is much too large for any chance of collision.  In Autumn 2026 the two spacecraft will return for a gravitational slingshot to boost them on to Mars transfer orbit, separating en route before arrival in later 2027. 

During the US government shutdown, another gravitational slingshot failed to make headlines or stimulate conspiracy accusations, though highly important.  The former OSIRIS-REx spacecraft is still in good shape after its visit to asteroid Bennu and return of samples to Earth – see ‘The Asteroid Hunter’, ON, 14^th September 2025.  Renamed OSIRIS-APEX, its next target was to be Apophis, the asteroid which caused such a stir in the 1990s when it seemed likely to hit the Earth in 2029, 2036 or 2068. 

It’s going to come very close, grazing the ‘comsat ring’ 22,000 miles up  (Fig. 17).  As it passes, Europe’s Ramses mission will try to make a close flyby  (Fig. 18), and OSIRIS-APEX will then attempt a rendezvous, going into orbit around Apophis for extended study.  The Trump administration was persuaded to drop its plan to cancel it, and it made a close pass of the Earth on September 23^rd at 2,100 miles, to set it on course for the encounter  (Figs. 19 & 20).  For video see Paul Scott Anderson, ‘OSIRIS-APEX mission to asteroid Apophis soars past Earth’, EarthSky, November 26^th, 2025.

A mission not on the list for termination, but in need of saving, is NASA’s Swift Gehrels gamma ray observatory  (Fig. 21), launched in 2004 and scheduled to end in 2024 when its orbit decayed, but still operational and highly valuable.  NASA has signed a contract with Arizona-based Katalyst Space Technologies to build a boosting spacecraft, expected to launch in the spring of 2026, rendezvous with Swift and raise its altitude.  One possible difficulty for Isaacman when he takes office is that allegedly NASA, under Duffy, has been wiping out the Goddard Centre although its closure has not been authorised by Congress or Senate – watch out for fireworks if that’s confirmed. (Mike Wall, ‘Private spacecraft will give NASA’s Swift space telescope an orbital boost in 2026 in 1st-of-its-kind mission’, Space.com, September 25^th, 2025.) 

Coming back to 3I/ATLAS, there was a moment of confusion when it was announced that the similarly named Comet 3/2025 K1 ATLAS had broken into two, possibly three parts  (Fig. 22;  David Unyime Nkanta, ‘Astronomical Spectacle:  Comet ATLAS Breaks Into Three Shining Fragments in November Sky’, International Business Times UK, 24^th November 2025.)  It’s quite normal for comet nuclei to fragment at perihelion, and indeed Prof. Avi Loeb briefly suggested that 3I/ATLAS might have done, to account for its major increase in brightness in October.  But it remains intact, with none of the breakup features seen in Comet West in 1975, for instance  (Fig. 23), or Biela’s Comet in 1846  (Fig. 24).  European observers have been watching the breakup since November 11^th, and we can expect to learn a great deal more about its composition – as happened with Comet West. 

Meanwhile, however, Avi Loeb drew attention to stacked images of 3I/ATLAS taken by amateur observers during November  (The Remarkable Large-Scale Structure of Anti-Tail and Tail Jets from 3I/ATLAS’, Medium, November 9^th 2025).  Most noticeable was the rearwards movement of the erupted material in the tail from an outburst around perihelion  (Fig. 25); 

by November 20^th it was much further back  (Fig. 26), due perhaps to a combination of sunlight pressure and ejection velocity. 

But astronomers often work with photographic negatives because details stand out more plainly, and in the upper panel of Fig. 26, remarkably, there is a huge x-shaped feature centred on the nucleus of the comet.  It’s very difficult to say what that could be:  the most obvious explanation is that it’s a satellite trail crossing the image, like the one doing so at the bottom.  Variations in prominence along the arms of the ‘X’ could indicate that whatever made it was rotating, like a discarded booster or shroud.  It would be a remarkable coincidence if it just happened to bisect the image of the nucleus, but such line-of-sight coincidences do happen – I described one in ‘Space Debris, Part 1’, ON, 13^th July 2025.  Or the ‘X’ could be an instrument fault, or an artefact of the image processing.  If its arms were the exhausts of sub-probes launched from a spacecraft, as Avi Loeb speculatively suggested, they would have to be moving very fast, not to be distorted by the rotation of the launcher, and to get so far in so short a time.  There’s no sign of them in positive images taken on 22-24 November  (Fig. 27;  Avi Loeb, ‘Images of 3I/ATLAS on November 22–24, 2025’, Medium, 25^th November 2025), nor on negatives I’ve seen elsewhere.

Meanwhile Avi Loeb has highlighted still another oddity about 3I/ATLAS, and this one has attracted more attention.  (Christingle May Pizazz, ‘3I/ATLAS Stuns Researchers With Surprise Trajectory Change, Ignites Dark-Matter Controversy’, International Business Times, 27^th November 2025.)  As I remarked last week that they would, the visually disappointing images of the comet from Mars Reconnaissance Orbiter have nevertheless allowed its orbit to be determined with 10 times greater accuracy, and in particular, to identify the changes in it brought about by mass emissions up to and during perihelion  (Lisa Lock and Andrew Zinin, ‘ESA pinpoints 3I/ATLAS’s path with data from Mars’, European Space Agency, Physics.org, 14^th November 2025).  The plot has allowed Avi Loeb to calculate that the comet is heading for the boundary of the Hill Sphere, where Jupiter’s gravity gives way to the Sun’s, and the course change during perihelion has brought it almost exactly to the edge.

Remarkable as that is, and reluctant as I am to resort to ‘coincidence’ when I encounter an oddity, let alone two in a row like this, it has to be said that they do occur in astronomy as well as in astronautics.  An example is that the star ElNath in the horns of Taurus, the Bull, is almost exactly opposite Antares, the brightest star in Scorpius.  It doesn’t mean that we are a way station on a space-line linking the two  (though we would be, if there were one.) 

As Fig. 28 shows, the pass is not actually going to be very close, because Jupiter’s Hill Sphere is a very large target.  The late Prof. Archie Roy was fond of remarking that if Jupiter’s gravitational field was visible to the naked eye, it would occupy quite a large area of sky.  And if the purpose was to drop probes into that field, or even into the planet, and 3I/ATLAS can alter its course, why not go a great deal closer and learn a great deal more?

It does at least guarantee that a lot of observatories, on Earth and in space, will be watching when the encounter takes place on March 16^th, 2026.  And ironically, it won’t be until nearly then that we get access to another set of data, which conspiracy theorists will no doubt claim is being withheld.  Back in the Autumn, much was being made of the observations which the JUICE probe would make in October of 3I/ATLAS, while on its own way to Jupiter  (Fig. 29).  They have indeed been made. 

But JUICE, ESA’s Jupiter Icy Moons Explorer, is designed to operate much further from the Sun than it is now.  To keep cool meantime, it’s using its high-gain antenna as a sunshade, while the low-gain antenna communices with Earth.  That’s why no photographs were taken during its Venus slingshot on 31^st August, when the antenna was protecting it from heat reflected from the planet.  By the time it reaches the Earth’s orbit, for two more flybys there, temperatures aboard will be low enough for the 3I/ATLAS data to be downloaded  (Earnest Daniel Nicolas, ‘ESA’s JUICE mission captures interstellar comet images, but solar heat delays release until 2026’, International Business News, 27^th November 2025).  That won’t be till February at the earliest, so once again, we shall just have to wait.

Duncan Lunan’s recent books are available from bookshops and through Amazon;  details are on Duncan’s website. www.duncanlunan.com.