From the publisher
NOTE; NO FURTHER DISCOUNT ON THIS PRINT PRODUCT-- OVERSTOCK SALE -- Signficantly reduced list price This study represents a means of highlighting the myriad of technological developments that made possible the safe reentry and return from space and the landing on Earth. This story extends back at least to the work of Walter Hohmann and Eugen Sanger in Germany in the 1920s and involved numerous aerospace engineers at the National Advisory Committee for Aeronautics (NACA)/NASA Langley and the Lewis (now the John H. Glenn Research Center at Lewis Field) and Ames Research Centers. For example, researchers such as H. Julian Allen and Alfred J. Eggers, Jr., at Ames pioneered blunt-body reentry techniques and ablative thermal protection systems in the 1950s, while Francis M. Rogallo at Langley developed creative parasail concepts that informed the development of the recovery systems of numerous reentry vehicles.
The chapters that follow relate in a chronological manner the way in which NASA has approached the challenge of reentering the atmosphere after a space mission and the technologies associated with safely dealing with the friction of this encounter and the methods used for landing safely on Earth.
The first chapter explores the conceptual efforts to understand the nature of flight to and from space and the major developments in the technologies of reentry and landing that took place before the beginning of the space age in 1957.
Chapter 2 also investigates the methods of landing once a spacecraft reaches subsonic speeds. Once the orbital energy is converted and the heat of reentry dissipated, the spacecraft must still be landed gently in the ocean or on land. Virtually all of the early concepts for human space flight involve spaceplanes that flew on wings to a runway landing; Sanger s antipodal bomber of the 1940s did so as did von Braun s popular concepts. However, these proved impractical for launch vehicles available during the 1950s, and capsule concepts that returned to Earth via parachute proliferated largely because they represented the art of the possible at the time.
Chapter 3 tells the story of reentry from space and landing on Earth fromthe beginning of the space age through the end of the Apollo program. Duringthat period, NASA and other agencies concerned with the subject developedcapsules with blunt-body ablative heat shields and recovery systems that reliedon parachutes. The Department of Defense (DOD) tested this reentry concept publicly with Project SCORE (Signal Communication by Orbiting RelayEquipment) in 1958 and employed it throughout the CORONA satellite reconnaissance program of the 1960s, snatching in midair return capsules containing unprocessed surveillance footage dangling beneath parachutes. With theMercury program, astronauts rode a blunt-body capsule with an ablative heatshield to a water landing, where the Navy rescued them. Project Gemini eventually used a similar approach, but NASA engineers experimented with a Rogallowing and a proposed landing at the Flight Research Center (now Dryden Flight Research Center) on skids similar to those employed on the X-15. When theRogallo wing failed to make the rapid progress required, NASA returned to theparachute concept used in Mercury and essentially used the same approach in Apollo, although with greatly improved ablative heat shields.
At the same time, the DOD pursued a spaceplane concept with the X-20Dyna-Soar orbital vehicle that would have replaced the ablative heat shield with
a reusable metallic heat shield and a lifting reentry that allowed the pilot to flythe vehicle to a runway landing. This is also the general approach pursued by the
DOD with its Aerothermodynamic Elastic Structural Systems EnvironmentalTests (ASSET) and Martin X-23A Precision Reentry Including Maneuvering
reEntry (PRIME) vehicles. NASA and DOD also experimented with liftingbody concepts. Engineers were able to make both of those approaches to reentry and landing work, making tradeoffs on various other capabilities in theprocess. The eventual direction of these programs was influenced more bytechnological choices than by obvious decisions.
Even as Apollo was reaching fruition in the late 1960s, NASA made thedecision to abandon blunt-body capsules with ablative heat shields and recovery systems that relied on parachutes for its human space flight program.Instead, as shown in chapters 4 and 5, it chose to build the Space Shuttle, a winged reusable vehicle that still had a blunt-body configuration but useda new ceramic tile and reinforced carbon-carbon for its thermal protectionsystem. Parachutes were also jettisoned in favor of a delta-wing aerodynamicconcept that allowed runway landings. Despite many challenges and the loss ofone vehicle and its crew due to a failure with the thermal protection system, thisapproach has worked relatively effectively since first flown in 1981. AlthoughNASA engineers debated the necessity of including jet engines on the Shuttle, it employed the unpowered landing concept demonstrated by the X-15 andlifting body programs at the Flight Research Center during the 1960s. Thesechapters lay out that effort and what it has meant for returning from spaceand landing on Earth.
The concluding chapter explores efforts to develop new reentry and landing concepts in the 1990s and beyond. During this period, a series of ideas
emerged on reentry and landing concepts, including the return of a metallicheat shield for the National Aero-Space Plane and the X-33, the Roton rotary
rocket, the DC-X powered landing concept, and the Crew Exploration Vehicle(CEV) of the Constellation program between 2005 and 2009. In every case,
these projects proved too technologically difficult and the funding was toosparse for success. Even the CEV, a program that returns to a capsule concept
with a blunt-body ablative heat shield and parachutes (or perhaps a Rogallowing) to return to Earth (or, perhaps, the ocean), pro
