The Stick is Stuck
The rumor mill at NASA Watch and Space Ref reports that development of the Crew Launch Vehicle (a.k.a. "The Stick") has run into some problems. I feel an "I told you so" coming on here, but hear me out.
The problems revolve around modifying the Space Shuttle main engine. Not only does NASA want to air-start it so it can be used on an upper stage, but NASA also wants to make it cheaper so they can be mass-produced and thrown away after each flight.
Here's some news for NASA: we already have a large, hydrogen-burning engine that is cheap and can be thrown away. It's the RS-68, and it's flown many times on the Delta IV. The RS-68 will probably need some modifications for an air-start as well, but the expendability is already built in. While RS-68 has a lower specific impulse than the shuttle engine (due mainly to the ablative cooling, instead of the shuttle's regenerative nozzle cooling,) it offers more thrust.
Of course, NASA's second engine choice is not the RS-68, but the J-2S. While this engine was a good one back in its day, it hasn't been produced in 35 years or so. Further, it's been revealed that the current upper stage design is too heavy to be propelled by two J-2S's working in tandem. NASA's solution to this one: shrink the upper stage, then add a fifth segment to the solid-rocket first stage. Come on, NASA. It's not like this is rocket science here...
At this point, we have to question the wisdom of choosing "The Stick" over a proven launcher like the Delta IV or Atlas V. While NASA has made a fuss about the challenges of "man-rating" these unmanned rockets, this point is specious. After all, "man-rating" never stopped NASA from using the Redstone, Atlas, and Titan II rockets back in the days when NASA was regarded as a competent agency. Man-rated or not, I'd feel safer riding a Delta or Atlas than I would feel riding in the Space Shuttle.
It would be wise to ask the engineers behind the Exploration Systems Architecture Study, Was "The Stick" really better than Delta & Atlas, or did you just do what Scott Horowitz told you to do? The former astronaut is now Director for Space Transportation and Exploration at ATK-Thiokol. If you think the decision to build The Stick was shady, I'd say that your B.S. detector has been well-calibrated.
[EDIT 1/19/2006] A canny reader of Transterrestrial Musings points out that Scott Horowitz has left ATK and became associate administrator for the Exploration Systems Mission Directorate at NASA in Sept. 2005. While I want to avoid making a personal attack against a man who has done great things for this nation, I wanted to point out that "The Stick" is his intellectual baby, and his positions of influence (at both ATK and NASA) undoubtedly helped it to gain acceptance within NASA.
Outside NASA, I don't think "The Stick" has found much acceptance. While Horowitz and NASA tout the solid rocket's simplicity as enhancing the rocket's reliability and safety, many of us don't agree. We remember the prescient words of Wernher von Braun, who warned against using solid rockets in manned spacecraft. And NASA's dirty little secret is that they still haven't addressed the OSHA issue with retrieval of the 5-segment SRB.
The problems revolve around modifying the Space Shuttle main engine. Not only does NASA want to air-start it so it can be used on an upper stage, but NASA also wants to make it cheaper so they can be mass-produced and thrown away after each flight.
Here's some news for NASA: we already have a large, hydrogen-burning engine that is cheap and can be thrown away. It's the RS-68, and it's flown many times on the Delta IV. The RS-68 will probably need some modifications for an air-start as well, but the expendability is already built in. While RS-68 has a lower specific impulse than the shuttle engine (due mainly to the ablative cooling, instead of the shuttle's regenerative nozzle cooling,) it offers more thrust.
Of course, NASA's second engine choice is not the RS-68, but the J-2S. While this engine was a good one back in its day, it hasn't been produced in 35 years or so. Further, it's been revealed that the current upper stage design is too heavy to be propelled by two J-2S's working in tandem. NASA's solution to this one: shrink the upper stage, then add a fifth segment to the solid-rocket first stage. Come on, NASA. It's not like this is rocket science here...
At this point, we have to question the wisdom of choosing "The Stick" over a proven launcher like the Delta IV or Atlas V. While NASA has made a fuss about the challenges of "man-rating" these unmanned rockets, this point is specious. After all, "man-rating" never stopped NASA from using the Redstone, Atlas, and Titan II rockets back in the days when NASA was regarded as a competent agency. Man-rated or not, I'd feel safer riding a Delta or Atlas than I would feel riding in the Space Shuttle.
It would be wise to ask the engineers behind the Exploration Systems Architecture Study, Was "The Stick" really better than Delta & Atlas, or did you just do what Scott Horowitz told you to do? The former astronaut is now Director for Space Transportation and Exploration at ATK-Thiokol. If you think the decision to build The Stick was shady, I'd say that your B.S. detector has been well-calibrated.
[EDIT 1/19/2006] A canny reader of Transterrestrial Musings points out that Scott Horowitz has left ATK and became associate administrator for the Exploration Systems Mission Directorate at NASA in Sept. 2005. While I want to avoid making a personal attack against a man who has done great things for this nation, I wanted to point out that "The Stick" is his intellectual baby, and his positions of influence (at both ATK and NASA) undoubtedly helped it to gain acceptance within NASA.
Outside NASA, I don't think "The Stick" has found much acceptance. While Horowitz and NASA tout the solid rocket's simplicity as enhancing the rocket's reliability and safety, many of us don't agree. We remember the prescient words of Wernher von Braun, who warned against using solid rockets in manned spacecraft. And NASA's dirty little secret is that they still haven't addressed the OSHA issue with retrieval of the 5-segment SRB.
posted by Mr. X at
5:51 PM
