Operation Uranus (Russian: Опера́ция «Ура́н», romanised: Operatsiya "Uran") was the codename of the Soviet Red Army's 19–23 November 1942 strategic operation on the Eastern Front of World War II which led to the encirclement of Axis forces in the vicinity of Stalingrad: the German Sixth Army, the Third and Fourth Romanian armies, and portions of the German Fourth Panzer Army. The Red Army carried out the operation at roughly the midpoint of the five-month long Battle of Stalingrad, aiming to destroy German forces in and around Stalingrad. Planning for Operation Uranus had commenced in September 1942, and developed simultaneously with plans to envelop and destroy German Army Group Center (Operation Mars) and German forces in the Caucasus. The Red Army took advantage of the German army's poor preparations for winter, and the fact that its forces in the southern Soviet Union were overstretched near Stalingrad, using weaker Romanian troops to guard their flanks; the offensive's starting points were established along the section of the front directly opposite Romanian forces. These Axis armies lacked heavy equipment to deal with Soviet armor.
|Part of the Battle of Stalingrad on the Eastern Front of World War II|
|Commanders and leaders|
|Casualties and losses|
Due to the length of the front lines created by the German 1942 summer offensive, which had aimed at taking the Caucasus oil fields and the city of Stalingrad, German and other Axis forces were over-extended. The German decision to relocate several mechanized divisions from the Soviet Union to Western Europe exacerbated their situation. Furthermore, Axis units in the area were depleted after months of fighting, especially those which had taken part in the fighting in Stalingrad. The Germans could only count on the XXXXVIII Panzer Corps, which had the strength of a single panzer division, and the 29th Panzergrenadier Division as reserves to bolster their Romanian allies on the German Sixth Army's flanks. In comparison, the Red Army deployed over one million personnel for the purpose of beginning the offensive in and around Stalingrad. Soviet troop-movements were not without problems: concealing their build-up proved difficult, and Soviet units commonly arrived late due to logistical issues. Operation Uranus was first postponed by the Soviet high command (Stavka) from 8 to 17 November, then to 19 November.
At 07:20 Moscow time on 19 November, Soviet forces on the northern flank of the Axis forces at Stalingrad began their offensive; forces in the south began on 20 November. Although Romanian units succeeded in repelling the first Soviet attacks, by the end of 20 November the Third and Fourth Romanian armies were in headlong retreat, as the Red Army bypassed several German infantry divisions. German mobile reserves proved insufficiently strong to parry the Soviet mechanized spearheads, while the Sixth Army did not react quickly enough nor decisively enough to disengage German armored forces in Stalingrad and re-orient them to defeat the impending threat. By late 22 November Soviet forces linked up at the town of Kalach, encircling some 290,000 Axis personnel east of the Don River. Instead of attempting to break out of the encirclement, German leader Adolf Hitler decided to keep Axis forces in Stalingrad and to resupply them by air. In the meantime, Soviet and German commanders began to plan their next movements.