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Aviation History
1964
1964 - 1092.PDF
fLIGHT International, 16 April 1964 623 NASA astronaut Virgil Grissom examines one of the Gemini spacecraft which will be used later in the programme for manned orbital flights lasting up to two weeks generators to start powering the turbine-driven pumps). Propellant tanks are gas pressurized to provide continuous uniform propellant flow and to sustain the integrity of the launch-vehicle structure. Staging takes place at 45 miles altitude and 45 miles downrange, when first-stage propellants are depleted. An electrical signal automatically arms a second-stage squib to fire the cartridge. Spacecraft The Gemini spacecraft is basically conical, with two major assemblies—a re-entry module and an adapter section. It is designed to shield the crew cabin from excessive heating, noise and meteorite penetration. During flight, the space- craft adapter section faces aft with respect to direction of travel. The re-entry module includes a nose fairing, rendezvous and recovery section, re-entry control section and cabin section. The rendezvous and recovery section, a truncated cone, is attached to the re-entry control system by 24 bolts. Its external surface is of beryllium shingles. The re-entry control section, cylindrical in shape, is located between the rendezvous and recovery section and the cabin section of the spacecraft. Its outer skin is beryllium. The cabin section, located between the re-entry control section and the adapter, has an internal pressure vessel shaped to provide adequate crew station with proper water flotation attitude. The shape also provides space between pressure compartment and outside conical shell for the installation of equipment. It is covered by heat-resistant shingles and has pressure bulkheads at each end. Two hatches on the top side of the cabin provide for entry and egress from the cabin. Two equipment bays are on each side of the cabin between pressure vessel and outer walls, and three additional bays are beneath the pressure-vessel floor. These bays are structur- ally designed for mounting equipment not requiring pressurization and for components having self-contained pressurization. Each of the hatches has a visual observation window with an inner and outer glass assembly. Two heat sensors are installed between the outer and inner glass assemblies to monitor thermal radiation, The adapter section is a truncated cone-shaped structure consist- ing of aluminium rings spliced together with magnesium stringers to form the basic structure. The forward end of the adapter is coupled to the re-entry module by three restraining rings. During the GT-1 flight the adapter section functions only as a vehicle to attach the spacecraft to the launch vehicle. The retrograde section at the forward end of the adapter is fitted to the bottom of the re-entry module. This section encloses the retrograde rockets. (Dummy rockets are used for the GT-1 flight.) The spacecraft is fitted to the launch vehicle by an aluminium ring 120in in diameter. This ring is attached to a similar launch-vehicle ring by 20 bolts, and in later flights will be separated by explosive charges. Spacecraft instrumentation and systems include:— (1) Instrumentation pallets (in place of crew couches), pressure transducers, temperature sensors and accelerometers are installed inside the cabin. The instrumentation equipment permits flight data to be telemetered to the ground stations. The cabin is purged and sealed prior to flight. The pallets are essentially platforms on which instrumentation and communications equipment is mounted, and the instrumentation provides a means of monitoring the condition of the spacecraft. A total of 104 measurements, concerning temperature, acceler- ation, and pressure, were telemetered to ground stations during the flight. These include 14 temperature, two acceleration and one pressure measurement of the rendezvous and radar-re-entry control sections; 29 temperature, nine acceleration and six pressure measure- ments of the conical section; and 36 temperature, five acceleration and two pressure measurements of the adapter section. Instru- mentation on Pallet No 1 weighs 2121b and on Pallet No 2, 1881b. Additionally, 8921b of ballast is mounted on the pallets. Instru- mentation pick-up devices are located throughout the spacecraft, and sound level measurements are made inside the cabin. (2) The environmental control system functions only to establish and maintain a cabin differential pressure. (3) Cooling system consists of a series of cold plates installed on the instrumentation pallets in the cabin. (4) Communications system (consisting of a C-band radar beacon, phase shifter, DC-AC inverter, three C-band antennas, three telemetry transmitters, and a UHF antenna) serves as an instru- mentation signal and spacecraft position link. (5) Electrical system consists basically of one main battery, several control relays and interconnecting wiring. (6) Functional systems not required for GT-1 are simulated with dummy packages where necessary for structural purposes. GT-I Test Vehicle Data Height 108ft: first stage 70ft, including engines; second stage 19ft; spacecraft and adapter 19ft. Diameter: launch vehicle first and second stages, !20in; adapter !20in at base, 90in at top; spacecraft 90in at base, 31 in at top. Launch weight: vehicle and spacecraft, 300,0001b; launch vehicle, approximately 293,0001b; spacecraft and adapter, approximately 7,0001b (adapter structural weight, 1811b). GEMINI-TITAN COUNTDOWN TIMET-lday T-360minT-330min T—300m in T-290minT-MOmin T-240minT-lMmln T-il5minT-l40min T-I35mi«T-Wmin T-5SminT-35min T-22minT-20min T-IOminT-«min T-W.ecT-47»ec T-I5.ec EVENT Partial propellant loading Propellant loading completed Launch vehicle and spacecraft power on, launch vehicle pressur- izatic. i begins Start countdown Spacecraft telemetry on Range readout of launch vehicle telemetry (No I) Mission control centre telemetry checks Launch vehicle simulated flight test Launch vehicle range destruct and engine shutdown checks Malfunction detection system talk sensor check Range readout of launch vehicle telemetry (No 2) Lift-off pulse check Spacecraft seal and leak check Erector lowering Auxiliary sustainer engine cut-off check Range engine shutdown test Spacecraft telemetry on, internal power Final status check of launch vehicle and spacecraft Launch vehicle power on Open launch vehicle pre-valves to allow propellants to flow to thrust chambers Launch vehicle destruct initiators armed TIME EVENT T —0 Start first stage engines. Spacecraft upper umbilical released T+I.8»ec Thrust chamber pressure switch, calibrated for 77 per cent of engine thrust, is activated, starting 2sec timer T + 3sec Spacecraft lower umbilicals released T+3.8sec Tiedown nuts explode T+4sec Lift-off begins. Flight control timer starts after 2in of vehicle travel T+IO.48sec Roll programmer is started for 72° launch azimuth T-r20.48.ee End of roll programme T+23.04sec Start first pitch programmer rate (gradual tilting from vertical to near-horizontal flight). This is accomplished in three separate increments. T-t-88.02.ec End first pitch programmer rate and start second pitch programmer rate T-r-ll9.04.ee End second pitch programmer rate and start third pitch pro- grammer rate T-f-I53.34sec First stage engine shutdown, booster engine cut-off, start second stage engine, explode stage separation explosive nuts T-r-l54.37.ec "Fire in the hole" staging accomplished T-f-l62.56.ec End third pitch programming T+335.23»ec Terminate radio guidance command steering T+337.23>ec Sustainer engine cut-off signal
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