FLEX beside Sentinel-3A
A satellite of European Space Agency moved up beside a satellite of European Commission DG-GROW Directorate I/2, Copernicus Unit, 59 km away at the nearest, and has stayed there for 11 days.
No report yet: no public report has named these two since the detector found them beside each other.
Beside right now · confirmed on October 28, 2026
- Nearest
- 58.8 km
- Oct 29 · 3:43 PM UTC
- Beside for
- 11 days
- since Oct 28, 6:04 AM UTC
- Took to come beside
- 21 days
- same plane Oct 7, same height Oct 7
- Orbit
- LEO
- low Earth orbit
- Last move
- FLEX
- Oct 7 · 3:11 PM UTC
The one it came up to
Sentinel-3A
European Commission DG-GROW Directorate I/2, Copernicus Unit, I-EU
41335 · 2016-011A · launched Feb 16, 2016
Whether European Space Agency or European Commission DG-GROW Directorate I/2, Copernicus Unit has said what this rendezvous was is not recorded yet. What others said is below; this page draws no conclusion.
The stages
Each step is one of Space-Track’s element sets, run through SGP4 and set against the other’s. A stage is raised by one set and confirmed when a later one agrees.
published 5:41 PM UTC
Same plane seen
FLEX’s orbit was found in Sentinel-3A’s plane, 0.031° off, and 4.76 km higher.
Δa +4.76 km · θ 0.031°
published 5:41 PM UTC
Same height seen
FLEX’s orbit had come to within 4.76 km of Sentinel-3A’s height.
1,282.14 km · Δa +4.76 km · θ 0.031°
published 7:01 PM UTC
Beside raised
A set placed FLEX beside Sentinel-3A. One set raises it; a later one must agree.
59.97 km · 59.5 km a day later · Δa +0.00 km · θ 0.029°
published 7:01 PM UTC
Beside confirmed
A later set agreed: FLEX stayed beside Sentinel-3A.
59.84 km · 59.4 km a day later · Δa +0.00 km · θ 0.028°
The moves
Each move is a change the detector read between two of an object’s element sets, beyond what drag and the Earth’s shape do: the speed change it implies, the change of height and the change of the orbit’s plane.
Reported elsewhere
No report elsewhere names this rendezvous yet.
Every verdict as numbers
| Stage | State | Set epoch (UTC) | Published (UTC) | Distance | A day later | Δa | θ | Exclusion |
|---|---|---|---|---|---|---|---|---|
| Same plane | seen | 2026-10-07 15:11:08 | 2026-10-07 17:41:50 | +4.76 km | 0.0308° | |||
| Same height | seen | 2026-10-07 15:11:08 | 2026-10-07 17:41:50 | 1,282.14 km | +4.76 km | 0.0308° | ||
| Beside | raised | 2026-10-28 06:04:00 | 2026-10-28 19:01:28 | 59.97 km | 59.49 km | +0.00 km | 0.0287° | |
| Beside | confirmed | 2026-10-28 14:29:04 | 2026-10-28 19:01:28 | 59.84 km | 59.42 km | +0.00 km | 0.0277° |
Δa is the semi-major axis of the one that moved less the other’s; θ is the angle between the two orbits’ planes. A day later is where the set puts the two 24 hours on, with no further manoeuvre. An exclusion tag on any of this rendezvous’s verdicts would keep it off the list; the pair’s other rendezvous are judged on their own.