Leros (Greek: Λέρος) is a Greek island and municipality in the Dodecanese in the southern Aegean Sea. It lies 317 kilometres (197 miles) (171 nautical miles) from Athens's port of Piraeus, from which it can be reached by an 11-hour ferry ride (or by a 45-minute flight from Athens). Leros is part of the Kalymnos regional unit. The island has been also called in Italian: Lèro and in Turkish: İleriye.
The island is 74 square kilometres (29 sq mi) and has a coastline of 71 kilometres (44 miles). The municipality includes the populated offshore island of Farmakonisi (pop. 10), as well as several uninhabited islets, including Levitha and Kinaros, and had a 2011 census population of 7,917, although this figure swells to over 15,000 during the summer peak. It is known for its imposing medieval castle of the Knights of Saint John possibly built on a Byzantine fortress. Nearby islands are Patmos, Lipsi, Kalymnos, and the small islands of Agia Kyriaki and Farmakos. In ancient times it was considered the island of Parthenos Iokallis and linked to the Hellenistic and Roman literature on Meleager and the Meleagrides. The administrative center and largest town is Agia Marina, with a population of 2,672 inhabitants. Other sizable towns are Lákki (pop. 1,990), Xirókampos (908), Kamára (573), and Álinda (542).
LEROS is a family of chemical rocket engines manufactured by Moog ISP Westcott United Kingdom. LEROS engines have been used as primary apogee engines for telecommunications satellites such as the Lockheed Martin A2100 as well as deep space missions such as Juno.
The family of LEROS engines derive from the original LEROS 1 engine which was developed and qualified in the 1990s by Royal Ordnance. The LEROS engines are all made of niobium alloy, which is traditionally used for liquid rocket engines such as the main engine of the Apollo Lunar Module. More than 70 LEROS 1 series engines have been delivered and have flown successfully.
LEROS engines have been used on a number of NASA and other space agency missions: