Existing　satellite　constellations　typically　lack　on-orbit　processing　capabilities,　and　on-orbit　data　backhaul　face　to　reliability　and　effiency　challenges.　Tiansuan　constellation　is　with　the　capability　of　providing　satellite　edge　computing　services,　which　can　support　complex　data　coding　transmission　methods.　To　effectively　support　effective　data　backhaul　for　existing　satellite　constellations,　we　propose　a　reliable　data　transmission　service　in　Tiansuan　constellation.　The　service　adopts　the　adaptive　coding　transmission　strategy　to　adjust　the　optimal　size　of　the　encoded　data　packet　according　to　real-time　satellite　network　conditions.　An　adaptive　encoding　transmission　approach　is　proposed　to　reduce　end-to-end　delay.　Experimental　results　based　on　the　ground　simulation　platform　demonstrate　that　the　proposed　method　can　effectively　reduce　end-to-end　delay　and　improve　effective　data　transmission　rate.　©　2023　IEEE.