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Old 01-30-2019, 01:52 PM
luke strawwalker's Avatar
luke strawwalker luke strawwalker is offline
Join Date: Dec 2007
Location: Needville and Shiner, TX
Posts: 5,911


First, Payload fairing separation into three parts, including the "debris-less" separation system using a tang-and-clevis arrangement at the base of the fairing panels to the vehicle mating ring, with the separation occurring when an explosive charge inflates the "bellows" to lift the clevis on the base of the panels up and clear of the tang...

Second, The available "payload dynamic envelope" within the fairing... (space available inside)

Third, An interesting bit of trivia on this graph-- payload fairing surface heating at various locations versus time after launch... notice that "point 3" on the top of the cylindrical portion of the shroud peaks at about 600 degrees F. about 200 seconds after launch... surprisingly, the base of the nose cone and the upper flanks of the nose cone, which one would "intuitively" expect to be hotter, are actually cooler. Probably interesting shock wave separation effect there...

Fourth, By comparison, the Titan IIIC, which was the alternative launcher for this proposal... not chosen because the Titan IIIC was more expensive due to the Transtage. Titan IIID was cheaper using direct ascent and injection of the payload directly from the second stage...

Fifth, Titan IIID flight profile for this proposed mission...

Sixth, Titan IIIC and IIID payload performance comparison for this mission... there were a couple of different trajectories proposed, which changed the available payload mass and required some changes to the mission and vehicle, such as adding a "kick stage" to the Titan IIID in lieu of using the Titan IIIC and its "Transtage". The selected method was, however, the direct injection of the payload directly into a 200 nautical mile circular orbit by the second stage of the Titan IIID, but of course this dinged the payload capability somewhat, limiting the mass of the payload the second stage could inject. Since the second stage of the Titan IIID was not capable of in-flight restart once it shut down, a Hohmann transfer, which would be more efficient, was out of the question, since it required a circularization burn at apogee to raise the perigee and circularize the orbit (which necessitated either the restartable Transtage, or a kick stage to perform the circularization burn).

Seventh, A chart showing the payload performance of the vehicle at various orbital inclinations-- notice that as the inclination decreases (towards a polar orbit) the payload capability is reduced markedly, due to the fact that one is not "gaining" any angular momentum from the rotation of the Earth at about 1,000 mph eastward as one does going into an equatorial orbit (when launching from near the equator), hence this additional speed must be provided by the vehicle and its propellants...

Eighth, An interesting chart showing the weights vs. time of the vehicle at various staging events during the vehicle's flight...

That's it for this one!

Later! OL J R
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