超级军网NASA为什么选择SRB作为星座计划的原因？
来源：百度文库 编辑：超级军网 时间：2024/04/30 04:04:14
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不能苟同，星座计划本来就是一次性火箭+卫星飞船的方案。否则为什么要使用RS-68/J-2，而不是SSME?
我个人的理解就是技术继承性，省钱。
我个人的理解就是技术继承性，省钱。
这片文档的潜台词就是"技术继承性，省钱。":L :L :L
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原帖由 暗夜流星 于 2008-7-30 00:15 发表
我觉得片面强调“复用”是不太合理的，省钱的途径有很多。一次性的发动机要考虑的东西就要少很多。
航天飞机走了弯路，实际上并不省钱。
我说的省钱主要是指节省研发费用。
另外我觉得航天飞机走的弯路是航天飞机这个概念造成的，而不是SRB:D
NASA的日子不好过，布什政府为了支持战争，砍掉了不少NASA的预算，很多好项目都砍掉了。格里芬只能保住主干，搞一两个大项目，这样才能保住NASA在民众中的影响力，有了影响力，议会才会给你拨款。
如果格里芬有足够的预算，不考虑维持SRB生产线的问题，一定会让RS-84作为第一级来使用。SRB用做第一级绝对不是什么好方案。
如果格里芬有足够的预算，不考虑维持SRB生产线的问题，一定会让RS-84作为第一级来使用。SRB用做第一级绝对不是什么好方案。
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其实NASA就是个官僚机构，本质上，和中国的官僚机构没有什么不同。
有一段时间，NASA的科学家怨声载道，很小笔的科研津贴都砍掉了。
原帖由 happywar 于 2008-7-30 00:42 发表
考虑到该报告发布的时机正值哥伦比亚号调查完成那段时间
我觉得你这种看法有点道理
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在性能可以满足任务要求的前提下，继承性可以带来高可靠性和低研发成本，这就是NASA选择SRB，RS68和J-2X的原因
现在对于Ares-1的质疑仍然不绝于耳，从官方到民间都有，有人认为用大力神或者德尔塔把飞船鼓捣上天更划算，也更快。
我个人不能理解NASA的想法，为了节省研发经费，而忽略了长远。要说继承性，SSME没有继承。其实SRB也不能满足要求，需要大改。光加长药柱是不管用的。
如果需要增大推力，喷管要改。如果需要增加燃烧时间，直径要改，这样改完了，也就不再是SRB了。
Ares-V的方案已经调整，RS-68的个数从5个增加到了6个。看来还是推力不够，不知道到时候弄出来是什么样子，我个人到是很有兴趣观看以固体火箭作为第一级的宇宙飞船发射上天。
我个人不能理解NASA的想法，为了节省研发经费，而忽略了长远。要说继承性，SSME没有继承。其实SRB也不能满足要求，需要大改。光加长药柱是不管用的。
如果需要增大推力，喷管要改。如果需要增加燃烧时间，直径要改，这样改完了，也就不再是SRB了。
Ares-V的方案已经调整，RS-68的个数从5个增加到了6个。看来还是推力不够，不知道到时候弄出来是什么样子，我个人到是很有兴趣观看以固体火箭作为第一级的宇宙飞船发射上天。
不过我觉得使用阿波罗的玩意来完成登月计划和火星探索好像也蛮划算和可靠的
毕竟那么多次成功载人登月的记录，谁都无法忽视
毕竟那么多次成功载人登月的记录，谁都无法忽视
暗夜老兄
你能不能详细分析一下为什么要反对Ares第一级使用SRB:o :o
你能不能详细分析一下为什么要反对Ares第一级使用SRB:o :o
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Ares-1的设计过于“另类”，当然我们可以说NASA艺高人胆大，但是我个人认为，这种设计是要冒风险的，尤其是用于载人飞船的发射。
来自WiKi的词条
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The proposed Ares I configuration has been criticized on several grounds. First, the production of a launch vehicle in the 25 tonnes (55,000 lb) payload class can be seen as direct competition with existing vehicles such as the Boeing Delta IV-Heavy. It can be argued that lower costs and improved safety are likely to result from the use of an existing vehicle, since it would have lower development costs, a proven track record, and would benefit from a higher flight rate. The NASA study group that selected what would become the Ares I concluded the opposite, however, and rated the vehicle as almost twice as safe as an Atlas or Delta-derived design.[14] Reports of growing political pressure from Congress to cancel the Shuttle-derived system and instead use existing Atlas/Delta vehicles began circulating in mid-2007.
Second, the configuration chosen by NASA requires two derivative engine development programs—both a new five-segment SRB for the first stage with its associated $3 billion development cost, and a new J-2X for the second stage with its associated $1.2 billion development cost. The extra cost, longer development schedule, and higher safety risk of new, unproven flight hardware all negate many of the supposed advantages of using 'shuttle-derived' hardware. In fact, critics say, the deletion of the SSME and four-segment SRB from the configuration removes the new vehicle from the class "Shuttle-Derived Launch Vehicles" entirely.[citation needed]
Third, technical objections may be raised over the aerodynamic stability of the proposed configuration. The tall, slender 'stick' configuration leads to a forward center of pressure and an aft center of gravity. Thus, the Ares I will continually tend to turn around, being most stable if flying backwards. The thrust vector control system on the SRB will have to constantly cope with this instability, which may lead to increased mechanical loads on the airframe. NASA has ongoing wind tunnel studies to address this problem.[citation needed]
Fourth, multiple delays in the Ares I development schedule due to budgetary pressures and unforeseen engineering and technical difficulties continue to increase the gap between the end of the Space Shuttle program and the first operational flight of Ares I. As of late 2007, the first operational Ares I flight is scheduled for late 2015, a full five years after the last Shuttle flight.[15][16]
Fifth, performance shortfalls with Ares I have resulted in a series of reductions to the capabilities, size, weight, and even redundant safety systems of the Orion spacecraft which will fly atop the Ares I.[17][18] [19]
Supporters of the Ares I claim that the vehicle is essential in ensuring the continued employment of the current STS workforce, as well as those involved in developing several critical components (like the five segment SRB and J-2X engine) of the larger Ares V vehicle. Critics claim that the continuing schedules delays will result in mass layoffs for much of the current STS workforce, similar to those that occurred between the Apollo and Shuttle programs, and that the continuing cost overruns will prevent Ares V from ever being built.
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The proposed Ares I configuration has been criticized on several grounds. First, the production of a launch vehicle in the 25 tonnes (55,000 lb) payload class can be seen as direct competition with existing vehicles such as the Boeing Delta IV-Heavy. It can be argued that lower costs and improved safety are likely to result from the use of an existing vehicle, since it would have lower development costs, a proven track record, and would benefit from a higher flight rate. The NASA study group that selected what would become the Ares I concluded the opposite, however, and rated the vehicle as almost twice as safe as an Atlas or Delta-derived design.[14] Reports of growing political pressure from Congress to cancel the Shuttle-derived system and instead use existing Atlas/Delta vehicles began circulating in mid-2007.
Second, the configuration chosen by NASA requires two derivative engine development programs—both a new five-segment SRB for the first stage with its associated $3 billion development cost, and a new J-2X for the second stage with its associated $1.2 billion development cost. The extra cost, longer development schedule, and higher safety risk of new, unproven flight hardware all negate many of the supposed advantages of using 'shuttle-derived' hardware. In fact, critics say, the deletion of the SSME and four-segment SRB from the configuration removes the new vehicle from the class "Shuttle-Derived Launch Vehicles" entirely.[citation needed]
Third, technical objections may be raised over the aerodynamic stability of the proposed configuration. The tall, slender 'stick' configuration leads to a forward center of pressure and an aft center of gravity. Thus, the Ares I will continually tend to turn around, being most stable if flying backwards. The thrust vector control system on the SRB will have to constantly cope with this instability, which may lead to increased mechanical loads on the airframe. NASA has ongoing wind tunnel studies to address this problem.[citation needed]
Fourth, multiple delays in the Ares I development schedule due to budgetary pressures and unforeseen engineering and technical difficulties continue to increase the gap between the end of the Space Shuttle program and the first operational flight of Ares I. As of late 2007, the first operational Ares I flight is scheduled for late 2015, a full five years after the last Shuttle flight.[15][16]
Fifth, performance shortfalls with Ares I have resulted in a series of reductions to the capabilities, size, weight, and even redundant safety systems of the Orion spacecraft which will fly atop the Ares I.[17][18] [19]
Supporters of the Ares I claim that the vehicle is essential in ensuring the continued employment of the current STS workforce, as well as those involved in developing several critical components (like the five segment SRB and J-2X engine) of the larger Ares V vehicle. Critics claim that the continuing schedules delays will result in mass layoffs for much of the current STS workforce, similar to those that occurred between the Apollo and Shuttle programs, and that the continuing cost overruns will prevent Ares V from ever being built.
SRB用于载人飞行确实让人感觉不把握
看看这个图就知道Ares-1有多长了，为了送20多吨载人飞船，犯得着吗？
要发射猎户座，其实宇宙神就足够了
战神I那细腰杆看着玄啊
战神I那细腰杆看着玄啊
原帖由 重剑无锋 于 2008-7-30 22:46 发表
要发射猎户座，其实宇宙神就足够了
战神I那细腰杆看着玄啊
说的是.米国人有点舍近求远
NASA另起炉灶设计AresI而不选delta/atlas发射Orion的原因可能有二：一是采用可复用的SRB的AresI发射成本可能要低于delta/atlas，且AresI和V共用助推和上面级本身也可以降低发射成本；二是EELV是空军的项目，个中利益冲突不言自明。
原帖由 cmj9808 于 2008-7-30 23:47 发表
NASA另起炉灶设计AresI而不选delta/atlas发射Orion的原因可能有二：一是采用可复用的SRB的AresI发射成本可能要低于delta/atlas，且AresI和V共用助推和上面级本身也可以降低发射成本；二是EELV是空军的项目，个中利益 ...
说得也是，美国佬各军种派系斗争实在是非常严重的。
NASA已经把LEO让给了空军，当年为LFBB搞的预研多半也给空军的ORS做了嫁衣，空军还得寸进尺，又惦记上星座计划了。
原帖由 happywar 于 2008-7-30 00:33 发表
另外我觉得航天飞机走的弯路是航天飞机这个概念造成的，而不是SRB:D
大型液体火箭燃烧稳定，如果从舒适性还是用液体火箭做芯级比较好考虑,Ares1的设计其实是向成本妥协,NASA也不能show me the money