The Mirage 2000N was designed to French requirements for an aircraft to replace the older Mirage IVP. Dassault received a contract to build two prototypes. The aircraft first flew on February 3, 1986. Seventy four were built up to 1993. The Mirage 2000N is based on the Mirage 2000B two-seat trainer, but features considerable changes. The airframe was strengthened for low-level flight and fitted with an Antilope 5 radar, which is used for terrain following, navigation and ground mapping, and which can follow terrain at 691 mph (1,112 km/h). Other avionic features are twin INS's and moving map displays for both the pilot and weapon systems officer. Weapons-wise, the Mirage 2000N can carry one ASMP medium-range nuclear missile, and can also carry two MATRA Magic AAM's for self defence. Other protection features include the Sabre jamming system and the Spirale chaff system. Because the extra seat decreases range, a pair of drop tanks are carried. The first batch of 30 aircraft for the French Air Force had a sole nuclear capability, and these were designated Mirage 2000N-K1. These did not have the Spirale chaff system, and carried a pair of AN.52 free-fall nuclear bombs before the ASMP was ready. The later batch of 44 aircraft were designated Mirage 2000N-K2. These had both a nuclear and conventional capability, and a full defensive fit. The K1 aircraft now have a limited conventional attack capability. The Mirage 2000N is the nuclear strike variant which was intended to carry the Aerospatiale Air-Sol Moyenne Portee (ASMP) nuclear stand-off missile. Initial flight tests of two prototypes began on February 3, 1983, and the Mirage 2000N entered operational service in 1988. A total of 75 were built. The fighter had strengthened wings for low-altitude operations, as well as low-level precision navigation/attack systems, built around the Dassault/Thales Antilope 5 radar, which was designed for the strike role and featured a terrain-avoidance capability.