A Launch Vehicle Valentine
Pausinias and Jeffrey Bell are predicting that the ever-shrinking CEV (now down to 5 meters instead of 5.5) will be moved off The Stick and onto the Atlas or Delta. Nonsense, I say. NASA is truly, madly, deeply in love with The Stick.
The love note that seals the deal is the ESAS report, chapter 6. One of NASA's most stressing requirements is limiting the loads placed on a crew during an abort. Because Delta and Atlas fly "lofted" trajectories, these loads will exceed NASA's limits while the second stage is firing. Instead, NASA wants a booster with a lot of thrust on the first stage so it can fly a depressed trajectory that avoids the unacceptable abort loads. The 5-Segment SRB that now forms the first stage of Stick puts out around 3,272,000 pounds of thrust; Atlas V has 931,000 pounds in vacuum, and Delta IV a wimpy 743,000 pounds in vacuum (source: Astronautix.com.) Bear in mind that the Stick is heavier than Atlas, and Atlas is heavier than Delta; there's a reason why those rockets have the amounts of thrust that they do. Still, Stick will probably have the thrust excess needed to fly the depressed trajectory NASA wants.
The question I have is whether NASA's abort loads requirements were legitimate. Did Redstone and Atlas D have the same concerns? At least with Titan II, a bailout from the Gemini capsule was by ejection seat; it became useless shortly after liftoff, when the astronauts would have encountered extreme speeds and altitudes that would have precluded safe ejection.
Until I see strong evidence otherwise, I'd say that NASA is head-over-heels in love with The Stick. Only an act of Congress (literally) will keep these crazy love birds apart.
I hope that my blunt double entendre wasn't too nauseating. Have a happy Valentines Day.
The love note that seals the deal is the ESAS report, chapter 6. One of NASA's most stressing requirements is limiting the loads placed on a crew during an abort. Because Delta and Atlas fly "lofted" trajectories, these loads will exceed NASA's limits while the second stage is firing. Instead, NASA wants a booster with a lot of thrust on the first stage so it can fly a depressed trajectory that avoids the unacceptable abort loads. The 5-Segment SRB that now forms the first stage of Stick puts out around 3,272,000 pounds of thrust; Atlas V has 931,000 pounds in vacuum, and Delta IV a wimpy 743,000 pounds in vacuum (source: Astronautix.com.) Bear in mind that the Stick is heavier than Atlas, and Atlas is heavier than Delta; there's a reason why those rockets have the amounts of thrust that they do. Still, Stick will probably have the thrust excess needed to fly the depressed trajectory NASA wants.
The question I have is whether NASA's abort loads requirements were legitimate. Did Redstone and Atlas D have the same concerns? At least with Titan II, a bailout from the Gemini capsule was by ejection seat; it became useless shortly after liftoff, when the astronauts would have encountered extreme speeds and altitudes that would have precluded safe ejection.
Until I see strong evidence otherwise, I'd say that NASA is head-over-heels in love with The Stick. Only an act of Congress (literally) will keep these crazy love birds apart.
I hope that my blunt double entendre wasn't too nauseating. Have a happy Valentines Day.
posted by Mr. X at
4:41 PM
