CSS (MENGTIAN)
Country: China, People's Republic of
Live Position
Ground Track · Last 90 Minutes
Upcoming Passes · Over Your Location
About This Satellite
Mengtian launched on October 31, 2022 as Tiangong's second laboratory module. Its facilities extend research in microgravity fluid physics, materials, combustion, and fundamental physics. It carries scientific equipment both inside the pressurized workplace and on external mounting locations, where experiments encounter a different environment.
A cargo airlock moves equipment outside the station
Mengtian's cargo airlock has inner and outer hatches and a payload-transfer arrangement. Equipment can be prepared inside, the airlock depressurized, and the payload presented outside for handling. This is a controlled transfer path, not a requirement to depressurize the whole laboratory whenever an external instrument is installed.
Precision clocks and cold-atom facilities ask different physics questions
The payload designers describe hydrogen, rubidium, and optical timing references alongside an ultra-cold-atom facility. The proposed investigations include precision time comparisons and fundamental physics. Those experimental capabilities should not be confused with an operational navigation broadcast service or a claim that every planned physics result has already been obtained.
Mission reference: CAS: Mengtian launch and scientific-payload designers' descriptions. Editorial review: .
A combustion experiment showed why flame shape changes in microgravity
In March 2023, CAS reported an ignition test in Mengtian's combustion cabinet. The two methane ignitions lasted about thirty seconds in total, with cameras and other diagnostics recording the experiment. The research team described a shorter, rounder outer diffusion flame than on the ground because buoyancy-driven convection was suppressed. This was a contained scientific experiment, not a flame burning in the vacuum outside the station.
Reference: CAS/Technology and Engineering Center for Space Utilization: Mengtian combustion test.
Three module names describe one assembled station
The December 2022 programme account identifies Tianhe, Wentian, and Mengtian as the station's basic three-module configuration. Mengtian's own catalog number records a separately launched component, not a separate working space station. Once attached, it shares the station's motion; historical launch elements should not be mistaken for the position of an independently flying laboratory.
Reference: CAS: Tiangong three-module configuration and application phase.
Reading this orbital snapshot
Based on TLE epoch: 2026-09-05. Estimated altitude ranges from 387 km at perigee to 390 km at apogee, a difference of 3 km. The orbital period is about 92.3 minutes. Eccentricity 0.00023 indicates a nearly circular path. In a two-body approximation, perigee speed is 1.00 times apogee speed. These are mean-element estimates, not instantaneous measurements. Distance per orbit uses an ellipse approximation.
Saved build snapshot. If a valid TLE is retrieved, this explanation and the orbit panel update together. Otherwise this dated snapshot is retained.
Ground track is not sensor coverage
An inclination of 41.47 degrees implies approximate geocentric ground-track limits of 41.5 degrees north and south. This is a prograde orbit, moving in the same general direction as Earth rotation. The plotted line marks the point beneath the object. It does not represent camera coverage, radio reception, or a guaranteed visible pass.
Accuracy and missing information
The introductory record describes the build snapshot. The orbital snapshot explanation and orbit panel share any successfully retrieved TLE; check the displayed epoch. Reentered objects retain historical data only. Mission history is not rewritten by TLE updates. TLE/SGP4 positions are predictions and can change after maneuvers or updated observations. The 14-day stale-data cutoff is a display safeguard, not an accuracy guarantee. Local passes are geometric predictions, not a visibility forecast. No verified operator or mission status means unknown, not active. Do not use this catalog for collision avoidance or operational flight decisions.
Catalog sources: CelesTrak SATCAT: NORAD 54216 · GCAT: S54216 (source update 2026 Sep 4 2345:57). Supplementary metadata: SatNOGS DB, retrieved 2026-09-05T12:57:25.375Z. Page assembled 2026-09-15. GCAT phase codes describe trajectory phases, not mission health.
Learn more: TLE data · Perigee and apogee · Ground tracks · JOT (Jewawud Live Orbital Map)