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GCNRevenger

Member

From: Earth

Registered: 2003-10-14

Posts: 6,056

Re: Falcon-IX and SpaceX

I had an idea about the Falcon-IX: Elon wants to make the first stage reuseable, right? The trouble is that it will reenter at a pretty high velocity, and it would be hard mount parachutes and a heat shield on the top while also accomdating the upper stage attach points to reenter nose-first. Coming down side first would be aerodynamically difficult to manage I bet too.

Anyways, my idea is to either delete the center engine or else wide the engine compartment a bit and mount the nine engines in a ring rather than a grid. In the space the center engine used to occupy, instead mount a telescoping aerospike that would deflect the hot gasses of reentry around the "open air" engine compartment to protect the engines. Perhaps the aerospike could be shaped to be aerodynamically self-righting, and making it spring-loaded would provide some cusioning for impact. This would keep the top of the rocket free for the required parachutes too.

Falcon-IX engine cluster:

I got this idea from the US Navy's Triden-II missile:

With all the hoop-la over Bigelow's inflatable modules and NASA's desire to get payload to the ISS or the Moon, I'm curious to hear how SpaceX is doing... They always seemed like the strongest contender for a workable commercial launch vehicle of the nessesarry scale with this design.

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cjchandler

Member

From: canada

Registered: 2006-06-24

Posts: 138

Re: Falcon-IX and SpaceX

That may work since the aerospike, the way I understand it at least, makes the shock cone stand out further from the body so one can assume that the plasma would be diverted. However I see two issues that need to be adressed. First, thoug I don't know how fast it will reenter, if it's generating plasma the thermal and even visible radiation could do a number on the engines and the shell. I think, from my limited knowlage, that this is the main reason why they have ablative heat shields on capsules and tiles on the shuttle, the plasma is itself is diverted by the detached shock cone, but the energy it radiates reaches the ship. Of course this depends on how fast you are rentering. I read that without blunt bodies and an attached shock cone a fast re-entery would reach 7800 K! Secondly, the aerospike reduces drag, on the minuteman upt to 50% percent. Do you really want to lower the drag? Depending on how high up it is and it's velocity upon stage seperation you may not have enough time to slow down with that small of a frontal area and that low of a Cd. Of course you could use a drouge parachute like the soyuz but for a large first stage I'm not sure that's possible. Best of Luck though, I'm somewhat partial to these non-standard wave drag reduction devises.

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