| Mission type | Technology demonstration |
|---|---|
| Operator | Deep Space Exploration Laboratory CNSA |
| Mission duration | 1 year, 8 months, 5 days(in progress) |
| Spacecraft properties | |
| Spacecraft | Tiandu |
| Manufacturer | Deep Space Exploration Laboratory |
| Start of mission | |
| Launch date | 20 March 2024, 00:31UTC[1] |
| Rocket | Long March 8[2] |
| Launch site | Wenchang Space Launch Site LC-2[3] |
| Orbital parameters | |
| Reference system | Selenocentricelliptic orbit |
| Lunar orbiter | |
| Orbital insertion | 24 March 2024, 17:43UTC[4] |
Tiandu satellites are a pair ofChinese Lunar Exploration Program'slunarnavigation andcommunications test satellites based onQueqiao-2 relay satellite technology.[5][6][7][8]
Tiandu satellites will performnavigation andcommunications technologyverificationexperiments while flying in formation inlunar orbit. Satellite-to-groundlaser ranging as well as intersatellitemicrowave ranging techniques will also be tested.[5][9]
The Tiandu satellites' mission is to inform the design of China's proposedQueqiaolunar navigation andcommunication array. Supporting services for lunar surface operations would be provided by such system.Line-of-sight communications limits affectuncrewed andcrewed operations on theMoon, especially at thelunar south pole, an area of great interest, or thelunar far side.[5][6][10]
The 61 kg (134 lb) Tiandu-1 carries aKadual-band integrated communication payload, a laser retroreflector, a space router and other payloads. The 15 kg (33 lb) Tiandu-2 carries a communication payload and navigation devices.[5][6][11]
The mission was launched together as a single probe withQueqiao 2 in 2024 on aLong March 8 rocket.[5][12]
After launch, the two satellites (while being attached to each other) underwent lunar orbit insertion on 24 March 2024 at 17:43UTC and entered a largeelliptical orbit around the Moon.[13] In that large elliptical orbit around the Moon, they separated on 3 April 2024[14] and later satellite-to-groundlaser ranging areinter-satellite microwave ranging are to be carried out by these satellites via high-precisionlunar orbit determination technology.[6][15][16]