Sentinel-3C and FLEX share a Vega-C in a week of twelve launches

The week behind · The week ahead

The week behind

The week’s launch to remember left Europe’s Spaceport in French Guiana at 01:21 UTC on Monday 15 September (22:21 on Sunday evening in Kourou), when Vega-C flight VV30 carried two ESA satellites at once: Copernicus Sentinel-3C and FLEX, the latest Earth Explorer. An adapter called Vespa stacked the two inside the fairing: Sentinel-3C, on top, was released first, and FLEX about an hour later; both satellites made contact with ESA’s operations centre in Darmstadt. FLEX is the first satellite built specifically to measure photosynthesis from space, reading the faint fluorescence that plants give off; it will fly in tandem with Sentinel-3A so that its readings can be matched with Sentinel-3’s near-simultaneous ones, and Sentinel-3C, the third of its series, is to take Sentinel-3A’s place in that pair later on. Once commissioned, Sentinel-3C passes to Eumetsat for routine operations while FLEX stays with ESA.

The International Space Station got its supplies. Roscosmos’ Progress 96 lifted off from Baikonur at 13:33 UTC on 16 September with about three tons of food, fuel and supplies for the Expedition 75 crew, and docked to the Poisk module at 13:44 UTC on Saturday 19 September; it stays about five months before a destructive re-entry that takes the station’s rubbish with it.

Two more Western launches: a Falcon 9 carried the USSF-259 national security mission from Vandenberg’s Space Launch Complex 4 East on the evening of 16 September local time (01:07 UTC on the 17th), the 63rd launch the base has supported in 2026, and the Space Force says nothing of what the payload is. And Rocket Lab’s Electron flew its 96th mission from Mahia at 03:22 UTC on 19 September, “Owl By The Dozen”, putting Synspective’s twelfth StriX radar-imaging satellite into a 572 km orbit; it was Electron’s 17th flight of the year, and Rocket Lab has fifteen more Synspective missions booked through the end of the decade.

China launched six times. LandSpace’s Zhuque-2E took ten SpaceSail broadband satellites to polar orbit from Jiuquan on 15 September, and that same evening Orienspace’s Gravity-1 took nine more from a ship in the Yellow Sea off Haiyang. A Long March 12 from Wenchang added nine satellites to the state-owned SatNet constellation on the 17th, a Kuaizhou 11 from Jiuquan carried two SpaceTY radar satellites two hours later, a Long March 2D from Taiyuan flew four PIESAT-2 X-band radar satellites on the 19th, and a Kinetica 1 closed the week from Jiuquan on Sunday morning. Russia’s Space Forces launched a Soyuz 2.1b with a Fregat upper stage from Plesetsk on 17 September; Launch Library lists it as a Glonass-K navigation satellite, while noting that the serial number and Cosmos designation are unconfirmed. Whichever it is, it joins the GLONASS constellation.

Our own count for the week: twelve orbital launches, ten of them with a successful outcome and two, Sunday’s, still without one in our data when this Briefing was written. Launch Library’s own entries have since marked both the Starlink flight and the Kinetica 1 successful.

Lift-off (UTC)	Launch	From	Outcome
15 Sep 01:21	Vega-C · Sentinel-3C and FLEX	Kourou, French Guiana	Success
15 Sep 06:26	Zhuque-2E · SpaceSail Polar Group 15	Jiuquan, China	Success
15 Sep 22:00	Gravity-1 · SpaceSail Polar Group 16	Yellow Sea, off Haiyang	Success
16 Sep 13:33	Soyuz 2.1b · Progress MS-35	Baikonur, Kazakhstan	Success
17 Sep 00:32	Long March 12 · SatNet LEO Group 25	Wenchang, China	Success
17 Sep 01:07	Falcon 9 · USSF-259	Vandenberg, California	Success
17 Sep 02:40	Kuaizhou 11 · SpaceTY-51 and 52	Jiuquan, China	Success
17 Sep 16:50	Soyuz 2.1b/Fregat · Glonass-K	Plesetsk, Russia	Success
19 Sep 03:22	Electron · Owl By The Dozen (StriX 12)	Mahia, New Zealand	Success
19 Sep 10:50	Long March 2D · PIESAT-2 13 to 16	Taiyuan, China	Success
20 Sep 01:47	Falcon 9 · Starlink Group 15-27	Vandenberg, California	Without one yet
20 Sep 04:00	Kinetica 1 · nine satellites	Jiuquan, China	Without one yet

The closest approach

The week’s closest pass in our conjunction data came at its very end: a fragment of the NOAA 16 weather satellite and a piece of a Long March 6A rocket, catalogue numbers 41295 and 54530, were predicted to pass 11 m apart at 20:35 UTC on Sunday 20 September, with a chance of collision of about 1 in 9,700 in the single report received so far. The best-observed was between two pieces of the same satellite: two fragments of Fengyun-1C, catalogue numbers 30464 and 36262, were predicted to pass 21 m apart at 01:34 UTC on 14 September, with a chance of collision of about 1 in 620 across nine reports; no collision was reported. Fengyun-1C was a Chinese weather satellite destroyed by an anti-satellite test on 11 January 2007, which NASA’s Orbital Debris Program Office called the single worst contamination of low Earth orbit in fifty years of spaceflight; nearly twenty years on, its pieces are still crossing each other’s paths. The week’s other approaches are on the Events page.

Manoeuvres

One Manoeuvre in the week among the Satellites we follow: Metop-C raised its orbit by about 128 m between the elements of 16 September 10:20 UTC and 17 September 13:22 UTC. EUMETSAT, which flies it, has said nothing of this burn; its newest polar satellite, Metop-SG A1, is drifting in tandem with Metop-C so that the two series’ data can be compared.

Satellite	Between (UTC)	Change
Metop-C	16 Sep 10:20 and 17 Sep 13:22	raised 128 m

Re-entries

The site’s Re-entries list is new and had not received its first decay query when this Briefing was drafted, so what came down this week is not told here.

The week ahead

Four launches are on the calendar for 21 to 27 September, all with dates that can still move; the Next launches page has them as they stand. Two are Chinese state launches whose payloads are not yet announced: a Long March 8A from Wenchang on the 23rd and a Long March 6A from Taiyuan on the 24th. On the 26th, Rocket Lab’s next Electron, “Owlright, Owlright, Owlright”, carries Synspective’s thirteenth StriX from Mahia, and a Falcon 9 flies USSF-385 from Vandenberg, a classified mission for the Space Force.

NET (UTC)	Launch	From
23 Sep 13:30	Long March 8A · payload not announced	Wenchang, China
24 Sep 08:45	Long March 6A · payload not announced	Taiyuan, China
26 Sep 00:15	Electron · Owlright, Owlright, Owlright (StriX 13)	Mahia, New Zealand
26 Sep 11:56	Falcon 9 · USSF-385	Vandenberg, California