aerofiction isn't that big of deal, carry so much fuel would be



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送交者: steven 于 2006-4-04, 15:02:29:

回答: 如果返回时用的助推器跟升空时用的一样,那所承受的加速度也是一样的 由 deadmeat 于 2006-4-04, 14:33:04:

a lot bigger problem. The different between reentry and launch is that: during launch, the rocket isn't at is top speed in the layers of atmosphere where air is dense. When the rocket reaches its top speed, there isn't much air left . Reentry is different, the rocket is still at a very high speed when it starts penetrating the dense atmosphere. What you proposed means that the breaking time is shorter, and that generates a much bigger force. In fact, the high heat isn't really a problem for both the shuttle orbiters or other SVs. The biggest problem in space is weight. Unlike airplane engine which inhales air and mixed with fuel vapor and explosed, the majority of mass that transfers to mv of the plane is from air. For SV launches, this is not the case. You carry the mass you throw to push yourself forward. More fuel you carries for reentry means less payload. Over 90% of the rocket mass is fuel. You can see how your proposal can fit in this formula.

One thing that people want is to use scramjet engine to push the SV to very high altitude where g and the air are less, and less fuel is required to push the SV to the orbit. As for return, the current apporach is quite effective and safe.



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