The Space Services, Incorporated (SSI) of Houston is one organization of entrepeneurs which plans to compete with the major commercial payload carriers. The SSI vehicle is know as Percheron. It is 1,2 m in diameter and almost 14 m tall; the addition of a nose cone and engine brings the final length to over 17 m. The pressure-fed engine has a potential thrust of 333 kN, although the first prototype reached only 265 kN and uses a coaxial pintle system like that on expendable launch vehicles and in the Apollo lunar module descent engine. This particular engine burns JP-4 kerosene as fuel with liquid oxygen as an oxidizer.
In 05.08.1981 the first rocket was destroyed during a static test. SSI have extensivaly revised their plans. The company has made a formal decision to switch to a multi-stage solid rocket to be designated the "Conestoga".

A privately-funded commercial launch vehicle built by Houston-based Space Services, Inc (SSI), which became the Space Service Division of EER Systems in 1990. Following a 1981 launch failure of its first, liquid-fuelled rocket named Percheron, SSI successfully tested its solid-propellant Conestoga-1, based on a Minuteman second stage engine, in 1982. However, the first operational flight of the rocket and the attempted launch of NASA’s Meteor satellite in 1995 failed when the vehicle was destroyed 45 seconds into its first stage burn. There have been no further launches.