超级军网Ares 1的第一级为什么要用固体火箭?
来源：百度文库 编辑：超级军网 时间：2024/04/20 15:31:18
导致整个火箭头大身子小，据说最近有NASA的工程师说计算机模拟显示 战神1 发射时不能承受稍微大点的风力，如果风力一大，火箭就会翻倒撞上发射塔．不知道是不是和它的气动布局有关？还有就是固体火箭的巨大的震动对火箭本身的硬件和宇航员都是一种伤害，不知道NASA怎么解决？导致整个火箭头大身子小，据说最近有NASA的工程师说计算机模拟显示 战神1 发射时不能承受稍微大点的风力，如果风力一大，火箭就会翻倒撞上发射塔．不知道是不是和它的气动布局有关？还有就是固体火箭的巨大的震动对火箭本身的硬件和宇航员都是一种伤害，不知道NASA怎么解决？
原因其实很简单，充分利用已有技术。
;P ;P ;P ;P
;P ;P ;P ;P
大概为了标新立异和省钱
本来NASA想把航天飞机的遗产都利用上，就是SSME和SRB。不过SSME太贵了，被迫选择了RS68。而航天飞机的4段SRB不够用，得加到5.5段。
如果战神I也用上RS68，会变成和德尔塔没区别，会给国会找个理由逼NASA上德尔塔的。本来德尔塔重型和宇宙神重型都可以胜任猎户座的发射，NASA就是要搞个怪异的东西划清界限。
本来NASA想把航天飞机的遗产都利用上，就是SSME和SRB。不过SSME太贵了，被迫选择了RS68。而航天飞机的4段SRB不够用，得加到5.5段。
如果战神I也用上RS68，会变成和德尔塔没区别，会给国会找个理由逼NASA上德尔塔的。本来德尔塔重型和宇宙神重型都可以胜任猎户座的发射，NASA就是要搞个怪异的东西划清界限。
也许就是NASA想上新项目。
原帖由 sd6632221 于 2008-11-8 20:35 发表
导致整个火箭头大身子小，据说最近有NASA的工程师说计算机模拟显示 战神1 发射时不能承受稍微大点的风力，如果风力一大，火箭就会翻倒撞上发射塔．不知道是不是和它的气动布局有关？还有就是固体火箭的巨大的震动对 ...
NASA的解释是，AresI原来设计抗风能力是34节，因为超过这速度的风在卡角是很少见的，但是计算机模拟发现来自南方的风如果超过某节的话，在起飞的前几秒里可能会造成尾喷管外沿擦碰发射架，即使没有碰到发射架，几乎百分之百的概率火箭喷射物会对发射架产生影响，给发射后的清理带来麻烦。如果将指标降至19节，也就是shuttle的最大抗风能力，那么就不存在这个问题了，但是这样一来发射窗口就受限了。
至于火箭的震动，现在的方案A是通过在尾喷口、上面级和助推级之间以及宇航员座椅的设计上增加减震器或缓冲系统，争取把宇航员受到的过载降至0.25g以内
SRB的可靠性比液体火箭高得多。并且是航天飞机的遗产技术，为何不加以利用？
我找到了美国专家对NASA为什么不用宇宙神5和德尔塔4进行载人航天的原因的解释：
http://blog.wired.com/wiredscience/2008/07/why-nasa-isnt-t.html
说的比较专业，不是看的太懂，请高手解释一下
http://blog.wired.com/wiredscience/2008/07/why-nasa-isnt-t.html
说的比较专业，不是看的太懂，请高手解释一下
干脆我把全文贴出来：
Why NASA Isn't Trying to Human-Rate the Atlas V or Delta IV Rockets
Some commenters have raised a very reasonable question: Why doesn't NASA just human rate an expendable launch vehicle like the Atlas V or the Delta IV? It seems reasonable because they fly all the time, they are big, they are reliable and they are already built. So what is the problem?
Weight- The Orion Crew Exploration Vehicle is too heavy for the Atlas V and the Delta IV (I will deal with other capsules after the jump). You also have to account for other mission constraints. For example, you have to include the loss of performance you get from going to the high inclination orbit of the International Space Station. ISS doesn't just fly directly over the equator but at an angle that allows it to pass over Russia. That orbit takes more energy to get to. In addition you will also lose performance because you have to fly a less aggressive launch profile. The current profile subjects payloads to 6 G's (Space Shuttle is 3 G's). Human payloads don't respond well to sustained 6 G loads. Flying a less aggressive profile will mean you will be able to lift less.
So all in all, you would need to develop a "triple-core" (three Atlas' strapped together) to be able to lift Orion. A triple core Atlas has never been flown. You would also need a new upper stage for an extra bit of kick at the end of the flight. The Delta IV, although larger and more mature, would also need a new upper stage.
Triple Redundancy- All human-rated vehicles are designed to be triply redundant. If something fails, there has to be two other options for the crew. It's like when the power goes out at your house, you have a back-up system which is a flashlight. If the flashlight fails, you have a second back up system which is a bunch of candles and matches. Now, to be stuck in the dark you would need to have all three systems fail. Cargo rockets are not designed with that much redundancy in their systems. Adding in that kind of redundancy after the fact would be like getting under the hood of your car and installing a back-up set of brakes. You have to create feed throughs for the wires, try to figure out where you will put the extra brakes etc.
Now to be fair, you could launch a smaller human vehicle on a current expendable rocket...(Orion does seat six).
In fact, before the Columbia disaster NASA teams were working on an Orbital Space Plane (OSP) designed to do just that. At the time, OSP was maligned for being small and limited in capability. (It is ironic that the Orion is now being maligned for being too large and capable.) OSP was a smaller vehicle designed to launch on an Atlas V or a Delta IV and seat "no less than four" crew members. It was eventually overcome by events when Constellation and the Moon, Mars, and beyond program kicked off and NASA transferred the knowledge gained on the OSP to the development of Crew Exploration Vehicle.
Then there is Robert Bigelow, a self made millionaire, who is building an inflatable space module hotel (they already have a scale model on orbit now). He is converging on a deal with Lockheed Martin to human-rate a version of the Atlas V. This is plausible, given that they are looking for an OSP-class capability. Bigelow's main interest is getting clients to and from his future orbiting facilities.
SpaceX is also building a small capsule that could launch people to ISS or Bigelow's space modules hotel. Their Dragon capsule, being built to take cargo to the International Space Station, will fit on their Falcon 9 rocket and be able to launch humans. Although it will not fly on an Atlas or a Delta, it is in that same class of vehicles.
Perhaps in the end it is a good idea for NASA to focus their efforts on building the new, heavier Orion capsule and the Ares I and V. These vehicles are suitable for the longer, more demanding trips to the moon. Then NASA could leave the lighter, smaller low Earth orbit capsules to commercial space to work out. That would serve both the goal of NASA being an exploration agency and of evolving our commercial space sector.
So the short answer is: NASA is not human-rating an Atlas V because that system will not be sufficient for exploration beyond low Earth orbit (though Bigelow Aerospace is looking at human-rating the Atlas V).
Why NASA Isn't Trying to Human-Rate the Atlas V or Delta IV Rockets
Some commenters have raised a very reasonable question: Why doesn't NASA just human rate an expendable launch vehicle like the Atlas V or the Delta IV? It seems reasonable because they fly all the time, they are big, they are reliable and they are already built. So what is the problem?
Weight- The Orion Crew Exploration Vehicle is too heavy for the Atlas V and the Delta IV (I will deal with other capsules after the jump). You also have to account for other mission constraints. For example, you have to include the loss of performance you get from going to the high inclination orbit of the International Space Station. ISS doesn't just fly directly over the equator but at an angle that allows it to pass over Russia. That orbit takes more energy to get to. In addition you will also lose performance because you have to fly a less aggressive launch profile. The current profile subjects payloads to 6 G's (Space Shuttle is 3 G's). Human payloads don't respond well to sustained 6 G loads. Flying a less aggressive profile will mean you will be able to lift less.
So all in all, you would need to develop a "triple-core" (three Atlas' strapped together) to be able to lift Orion. A triple core Atlas has never been flown. You would also need a new upper stage for an extra bit of kick at the end of the flight. The Delta IV, although larger and more mature, would also need a new upper stage.
Triple Redundancy- All human-rated vehicles are designed to be triply redundant. If something fails, there has to be two other options for the crew. It's like when the power goes out at your house, you have a back-up system which is a flashlight. If the flashlight fails, you have a second back up system which is a bunch of candles and matches. Now, to be stuck in the dark you would need to have all three systems fail. Cargo rockets are not designed with that much redundancy in their systems. Adding in that kind of redundancy after the fact would be like getting under the hood of your car and installing a back-up set of brakes. You have to create feed throughs for the wires, try to figure out where you will put the extra brakes etc.
Now to be fair, you could launch a smaller human vehicle on a current expendable rocket...(Orion does seat six).
In fact, before the Columbia disaster NASA teams were working on an Orbital Space Plane (OSP) designed to do just that. At the time, OSP was maligned for being small and limited in capability. (It is ironic that the Orion is now being maligned for being too large and capable.) OSP was a smaller vehicle designed to launch on an Atlas V or a Delta IV and seat "no less than four" crew members. It was eventually overcome by events when Constellation and the Moon, Mars, and beyond program kicked off and NASA transferred the knowledge gained on the OSP to the development of Crew Exploration Vehicle.
Then there is Robert Bigelow, a self made millionaire, who is building an inflatable space module hotel (they already have a scale model on orbit now). He is converging on a deal with Lockheed Martin to human-rate a version of the Atlas V. This is plausible, given that they are looking for an OSP-class capability. Bigelow's main interest is getting clients to and from his future orbiting facilities.
SpaceX is also building a small capsule that could launch people to ISS or Bigelow's space modules hotel. Their Dragon capsule, being built to take cargo to the International Space Station, will fit on their Falcon 9 rocket and be able to launch humans. Although it will not fly on an Atlas or a Delta, it is in that same class of vehicles.
Perhaps in the end it is a good idea for NASA to focus their efforts on building the new, heavier Orion capsule and the Ares I and V. These vehicles are suitable for the longer, more demanding trips to the moon. Then NASA could leave the lighter, smaller low Earth orbit capsules to commercial space to work out. That would serve both the goal of NASA being an exploration agency and of evolving our commercial space sector.
So the short answer is: NASA is not human-rating an Atlas V because that system will not be sufficient for exploration beyond low Earth orbit (though Bigelow Aerospace is looking at human-rating the Atlas V).
偶的英语不好，上面的文章也不是特别明白
意思似乎是说宇宙神5和德尔塔4的运载能力不够，要是用三芯级的需要新开发上面级，而且三芯的宇宙神5还没飞过
下面的意思是说飞船必须很大，如果造个宇宙神5能发射的小飞船那性能不足以满足未来的需求
宇宙神5只能发射低地轨道的飞船
意思似乎是说宇宙神5和德尔塔4的运载能力不够，要是用三芯级的需要新开发上面级，而且三芯的宇宙神5还没飞过
下面的意思是说飞船必须很大，如果造个宇宙神5能发射的小飞船那性能不足以满足未来的需求
宇宙神5只能发射低地轨道的飞船
主要意思是EELV
a.现有设计不足以将CEV送上位于高倾角轨道的ISS，要么CEV减重（那它就去不了月球），要么设计新的EELV，包括助推和上面级
b.EELV是按照货运设计的，冗余度和加速度均不适合用于载人（但同时提到bigelow和spacex的载人飞船却是用类似EELV的发射系统）
结论：EELV用来发射一个小号的CEV进行LEO运输也许是可行的，但不适用于星座计划
a.现有设计不足以将CEV送上位于高倾角轨道的ISS，要么CEV减重（那它就去不了月球），要么设计新的EELV，包括助推和上面级
b.EELV是按照货运设计的，冗余度和加速度均不适合用于载人（但同时提到bigelow和spacex的载人飞船却是用类似EELV的发射系统）
结论：EELV用来发射一个小号的CEV进行LEO运输也许是可行的，但不适用于星座计划