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NASA releases long-awaited draft solicitation for next phase of post-ISS commercial space station plan. nasa.gov/humans-in-space/com…

The Space Shuttle’s R-bar Pitch Maneuver (RPM), dramatically nicknamed the "backflip", was one of the most visually striking and critically important procedures in the post-Columbia era of shuttle missions.Introduced as a direct response to the tragic STS-107 Columbia disaster in 2003—where launch debris fatally damaged the orbiter's heat shield—this 360° pitch rotation became a mandatory safety step before every docking with the International Space Station (ISS).As the shuttle approached along the R-bar (the radial vector from Earth's center through the ISS, essentially flying "below" the station), it paused at roughly 600 feet (about 180–183 meters) separation. Then, with the commander at the controls, the orbiter executed a slow, controlled end-over-end roll at approximately 0.75 degrees per second. The full 360° maneuver typically lasted 8–9 minutes, exposing the shuttle's vulnerable underside—its thermal protection system (TPS) of thousands of heat-resistant tiles—to the ISS crew's high-resolution cameras (often equipped with 400mm and 800mm telephoto lenses).ISS astronauts, positioned at windows in modules like Zvezda or Destiny, snapped hundreds of detailed photos during the ~90-second optimal belly-up window. These images were immediately downlinked to Mission Control for rapid analysis by engineers on the ground, hunting for any signs of tile damage, missing pieces, or debris impacts that could jeopardize re-entry. Combined with inspections from the shuttle's own Orbiter Boom Sensor System (OBSS), the RPM provided unprecedented assurance that the vehicle could safely return home.This choreographed ballet—requiring pinpoint piloting, precise attitude control via Reaction Control System thrusters, and flawless coordination between shuttle and station crews—turned a routine rendezvous into a high-stakes safety ritual. Performed flawlessly on missions from STS-114 (Discovery, 2005, first RPM under Eileen Collins) through the program's end in 2011, it exemplified NASA's commitment to "return to flight" lessons learned.Credit: NASA (Iconic views from the ISS during RPM: the shuttle's heat shield tiles fully exposed against Earth's backdrop, revealing the intricate mosaic of the TPS in stunning detail.)