Blackstar is the reported codename of a secret United States orbital spaceplane system. The possible existence of the Blackstar program was reported in March 2006 by Aviation Week & Space Technology (Aviation Week, AWST) magazine; the magazine reported that the program had been underway since at least the early 1990s, and that the impetus for Blackstar was to allow the United States government to retain orbital reconnaissance capabilities jeopardized following the 1986 Challenger disaster. The article also said that the United States Air Force's Space Command was unaware of Blackstar, suggesting it was operated by an intelligence agency such as the National Reconnaissance Office. Aviation Week speculated that such a spacecraft could also have offensive military capabilities, a concept colloquially known as "The Space Bomber". The magazine also stated that it was likely that Blackstar would be mothballed, although it is unclear whether this is due to cost or failure of the program. The Aviation Week report was dismissed a few days later as "almost certainly bogus" and the project termed a "technical absurdity" by Jeffrey F. Bell in an article in Space Daily. The Blackstar system Aviation Week describes Blackstar as a two-stage-to-orbit system, the first stage of which is a delta-winged supersonic jet (which Aviation Week referred to as the SR-3). Its description of SR-3 is similar to the North American B-70 Valkyrie Mach 3 strategic bomber, and to patents filed in the 1980s by Boeing. The SR-3 would carry a second, smaller airframe, codenamed the XOV (eXperimental Orbital Vehicle) underneath, between its two laterally separated engine-banks, each containing 2 or 3 engines. This rocket-powered spaceplane, with similarities to the X-20 Dyna-Soar project, would be released by its mothership at an altitude of around 100,000 feet. The XOV would then light its rocket motor (aerospike engines, similar to those used by the Lockheed Martin X-33), and could achieve both suborbital and orbital flight; one source quoted by Aviation Week estimates the XOV could reach an orbit of above the Earth, depending on payload and mission profile. The XOV would then reenter the atmosphere and glide back to any landing site where it would land horizontally on a conventional runway. This combination of jet-powered mothership and a smaller rocket-powered spaceplane resembles the civilian Tier One spaceplane system as well as NASA's X-15, but capable of much higher velocities and thus of attaining orbit. Readers are cautioned to examine the