Owing　to　the　enormous　amount　of　frozen　water　and　the　particularity　of　heat　exchange,　polar　ice　sheets　act　as　an　important　indicator　and　amplifier　of　global　climate　change.　However,　the　detection　and　cognition　of　the　tomographic　structure　of　polar　ice　sheets　remain　insufficient　due　to　the　special　geographical　location　and　harsh　weather.　Benefit　from　the　advantage　of　strong　penetrability　and　high-precision　range　measurement,　the　ice　sounding　radar　is　an　optimal　instrument　for　tomographic　detection　of　polar　ice　sheets,　which　significantly　promotes　the　development　of　polar　science.　Nevertheless,　existing　radar　satellites　still　cannot　detect　ice　beds　in　depth　because　of　the　complex　low-frequency　signal　propagation　in　ice　and　an　extremely　long　operating　distance.　This　study　focuses　on　the　scientific　objectives　(spatial　resolution:　100　m　and　revisit　time:　3　months)　and　presents　an　in-depth　analysis　of　the　key　problems　of　orbital　ice　sounding　radar,　including　transmission　attenuation,　firn　clutter,　and　cross-track　resolution　deterioration.　With　reference　to　the　current　state　and　trend　of　radar　satellite　technology,　we　proved　the　feasibility　of　the　application　of　distributed　Synthetic　Aperture　Radar　(SAR)　on　the　microsatellite　platform　for　ice　bed　detection,　identified　the　key　parameters　of　distributed　SAR　and　the　technical　challenges　of　orbital　radar　sounding　system　for　polar　ice　sheet　tomographic　observation,　and　further　explored　the　implementation　scheme.　©　2022　Institute　of　Electronics　Chinese　Academy　of　Sciences.　All　rights　reserved.