The Observatory — July 25, 2026

I · Now observing

A Soyuz reaches the space station in three hours and four minutes, threading a two-orbit chase

A Soyuz carrying three people reached the International Space Station a little over three hours after leaving the ground, a chase that only closes if the rocket lifts off within seconds of its appointed instant.[1][3] The Soyuz-2.1a rose from Baikonur at 14:47 UTC on July 14, and the Soyuz MS-29 spacecraft docked to the station’s Prichal module at 17:52 UTC, flying the two-orbit profile that has replaced a two-day approach.[1][3] Aboard were the Roscosmos cosmonauts Pyotr Dubrov and Anna Kikina and NASA’s Anil Menon, on his first flight.[2][4] The crew rotation is ordinary; the timing that delivered it is not.

01 What happened

The launch left Site 31/6 at the Baikonur Cosmodrome in Kazakhstan at 14:47 UTC, and the spacecraft caught and docked with the station about three hours later, at 17:52 UTC, mating automatically to the nadir port of the Prichal module on the Russian segment.[1][3] Prichal is the small spherical node added in 2021 to give that segment more docking ports.[3] Hatches opened soon after, and Dubrov, Kikina, and Menon joined the crew already aboard for a stay of about eight months, with a return planned for around April 2027.[1][5] Dubrov and Kikina were each on a second flight; Menon flew under the standing arrangement that keeps a NASA astronaut on Russian ferries and a cosmonaut on American ones.[3][4]

3 h 04 min

from liftoff to docking, a two-orbit rendezvous

51.6° / ~420 km

the station’s orbit the Soyuz had to match

~92 min

one station orbit, so two laps is about three hours

02 The mission in numbers

The station circles at roughly 420 kilometers, tilted 51.6 degrees to the equator.[3] That angle is not arbitrary. It is the inclination a rocket leaving Baikonur, near 46 degrees north, can reach while flying straight along its planned track, without the costly turn that changing an orbital plane demands.[3] A rendezvous profile counts how many laps the chaser spends catching its target. The two-orbit scheme flown here, near three hours, and the four-orbit scheme, near six, have largely replaced the old thirty-four-orbit approach that took two days.[3] The final approach is flown under Kurs, the radio-navigation system that brings the closing speed down to a few centimeters per second before the docking latches catch.[1][3]

The two-orbit rendezvous. The Soyuz is placed below the station’s orbit, where it moves faster and closes the phase gap before rising to match.[3]

03 Why it is hard

A rendezvous is the problem of putting two bodies at the same point of the same orbit at the same moment, and an orbit is unforgiving about all three of plane, altitude, and phase.[3] The most expensive of these is plane. The cost of tilting an orbit rises with orbital speed, which is close to 7.7 kilometers per second here, so an error of even a degree would ask for propellant a Soyuz does not carry.[3] The answer is to launch at the instant the station’s ground track crosses the pad, which opens the window for only a moment, roughly once a day.[3] The two-orbit chase adds a second constraint on top of the first. The station must sit at a particular angle ahead of the launch site at liftoff, so that the Soyuz, dropped into a lower and therefore faster orbit, closes the gap in about three hours before rising to match.[3] A lower orbit completes a lap sooner, which is Kepler’s third law doing the catching up.[3] The margin in that phase angle is small, and if the launch or the insertion drifts outside it, the crew falls back to the slower four-orbit or two-day path.[3] What the flight shows is not new hardware but a hard piece of guidance and timing now flown routinely, with a first-time astronaut aboard, at the start of an eight-month tour.[3][4]

04 What to watch

The crew now aboard rotates out in the weeks that follow, and the next Soyuz will test whether the swapped-seat arrangement between the two agencies continues; MS-29’s own undocking and landing are set for around April 2027.[5]

Sources

II · From the archive

The Christmas Eve launch that let Europe stop borrowing rockets

For four years in the early 1970s, Europe could build communications satellites but was not allowed to sell rides on the American rockets it had to borrow to launch them.[2] A single launch on Christmas Eve 1979 began to end that dependence. Ariane 1 reached orbit, and within five years the company built around it was booking about half the world’s commercial satellite launches.[3][5]

01 The story

Europe’s first try at a launcher had been a wreck. The multinational Europa rocket flew eleven times between 1968 and 1971 and reached orbit not once, its British first stage working every time while an upper stage failed every time, and the program was abandoned in 1973 after more than 250 million pounds.[1] The humiliation had a sharp edge. When Europe’s Franco-German Symphonie satellites were left without a ride, the United States agreed to launch them on Delta rockets in 1974 and 1975 only under terms that forbade putting them to any commercial use.[2][6] Europe could experiment in space, but not compete there. In the summer of 1973 the space ministers of ten countries met in Brussels and approved a new launcher, soon named Ariane after the Ariadne of myth who handed Theseus the thread out of the labyrinth.[3] Run by the new European Space Agency at a cost near two billion euros, it was a three-stage rocket burning storable propellants in a cluster of Viking engines.[4] The first launch attempt on December 15, 1979 was stopped; the second, on December 24, carried a 1,645-kilogram test capsule to orbit and worked.[3] The road stayed rough, and the second Ariane exploded the following May, but the company founded to sell the rocket flew its first paying flight in 1984.[4][5]

02 The hard part

The problem was never a single exotic part; it was making the stages hand off to one another reliably, exactly where Europa had died.[1] Ariane’s designers chose pragmatism, clustering four Viking engines burning storable propellants on the first stage and avoiding the cryogenic complications that had helped sink earlier efforts, while still building a high-energy third stage to reach the transfer orbit toward geostationary height.[4] Clustered liquid engines punish small mistakes. Combustion instability, in which pressure waves inside a chamber lock into step with the flow of propellant and can tear an engine apart in milliseconds, was still a half-empirical problem in the 1970s, and it is what destroyed the second Ariane 1 in May 1980.[4] The team had to find and damp those oscillations with the instruments of the day, across engines firing together, without being able to model the coupled acoustics fully before flight. That they closed the problem and drove the rocket to nine successes in eleven flights, against Europa’s zero, is the point.[4][1]

0/11 → 9/11

orbital successes: Europa to Ariane 1

~0% → ~50%

European commercial launch share by early 1984

1,645 kg

test capsule on the first flight, Dec. 24, 1979

03 Why it mattered, measurably

The measure that moved was market structure. Before Ariane, Europe’s share of the commercial launch business was effectively nothing, because it had no working launcher of its own and its satellites flew abroad under a ban on selling their services.[2][1] After the 1979 success and the creation of Arianespace, the first company set up purely to sell launches, the numbers moved quickly: by early 1984 it had booked 27 satellites, roughly half the world market of the day.[5] That share held and grew, past half of the geostationary-transfer market by 2004 and toward 60 percent a decade later, by the company’s own count, before newer American rockets overtook it from 2017.[5] The reliability figure moved just as sharply, from zero orbital successes in eleven Europa flights to nine in eleven for Ariane 1, and the bookings rested on that credibility.[1][4] The American shuttle was meant to carry commercial payloads and hold prices down, and its grounding after 1986 left Ariane as the dependable alternative, so some of the gain reflects a rival’s misfortune as much as Ariane’s merit.[5] Within half a decade, a continent barred from selling a launch had come to own most of that business.[2][5]

European share of the commercial launch market, by Arianespace’s own count, from before Ariane to the mid-2010s.[5]

04 Echoes today

The line from that Christmas Eve runs to the present. Arianespace counts more than 355 missions and over 1,100 satellites across 45 years, and independent European access to space is still the stated reason for building its successor, Ariane 6.[4][5] The argument that answered the Symphonie affair, that a bloc must be able to fly its own strategic payloads without a foreign veto, is now made almost word for word by every power building a launcher of its own.[3][5] And the commercial market Ariane pried open is the one those newer rockets later took, which is its own kind of proof.[5]

Sources