http://www.projectrho.com/rocket/enginelist.php#id--Gaseous_Core_Nuclear_Thermal_Rockethttp://en.wikipedia.org/wiki/Gas_core_reactor_rocketHow practical would this be? How much of a technological leap would be needed to achieve this?
Would it make outer solar system missions possible?
Could the technology be used for non space applications?
Closed cycle has more merit, I'm a little bit of a fan of the "Nuclear Lightbulb", but admittedly that concept only allows a relatively modest increase over a solid core.
Why would you care about fission products exiting your engine in space, unless you aim your exhaust plume at something inhabited?The fission products would travel at a velocity far exceeding solar escape velocity, and interplanetary space is filled with deadly ionising radiation anyway ...
For the "nuclear lightbulb," it's about 1800-3000 sec, depending on your source. Figure in the fact that increasing Isp has an exponential effect on your DV, and the benefits are even greater.However, I'm practical and don't think that gas-core is a viable technology any time soon - provided that no "quantum leap" in materials engineering occurs.
http://www.projectrho.com/rocket/enginelist.php#id--Gaseous_Core_Nuclear_Thermal_Rockethttp://en.wikipedia.org/wiki/Gas_core_reactor_rocket
How practical would this be?
How much of a technological leap would be needed to achieve this?
Compared to what? It's much less developed than NERVA and probably less polluting than an Orion drive.
Do you mean crewed outer solar system missions? They *are* possible with other methods whose TRL is *much* higher than this. It depends how much someone wanted to trash their home planet and pollute the rest of the solar system.
If you're not focused on solely on getting some extreme ISP out of it gas core reactor rockets can actually be a simpler solution. There is a NTRS paper on a Nuclear Vapor Thermal Reactor that could be easier to build than a new NERVA. http://hdl.handle.net/2060/19960020451It uses the same basic NERVA design but dispenses with complex fuel construction for fuel channels of UF4 surrounded by Hydrogen channels. This has the benefit of potentially easier refuelling and reusability, improved safety and a good ISP.
The T/W ratio of 5.0 for the C-C moderated design is higher than most realistic NERVA designs.
Here's an idea - how about an NVTR with LOX augmentation? Such a design would have a great T/W ratio and the Isp of a solid-core NTR.
Figure in the fact that increasing Isp has an exponential effect on your DV, and the benefits are even greater.
Quote from: lkm on 09/18/2011 07:41 pmIf you're not focused on solely on getting some extreme ISP out of it gas core reactor rockets can actually be a simpler solution. There is a NTRS paper on a Nuclear Vapor Thermal Reactor that could be easier to build than a new NERVA. http://hdl.handle.net/2060/19960020451It uses the same basic NERVA design but dispenses with complex fuel construction for fuel channels of UF4 surrounded by Hydrogen channels. This has the benefit of potentially easier refuelling and reusability, improved safety and a good ISP.Fascinating concept - I've never seen it before. The T/W ratio of 5.0 for the C-C moderated design is higher than most realistic NERVA designs. Here's an idea - how about an NVTR with LOX augmentation? Such a design would have a great T/W ratio and the Isp of a solid-core NTR.
Quote from: jbrooks on 09/19/2011 01:06 amThe T/W ratio of 5.0 for the C-C moderated design is higher than most realistic NERVA designs.QuoteHere's an idea - how about an NVTR with LOX augmentation? Such a design would have a great T/W ratio and the Isp of a solid-core NTR.Not at the same time. You lose Isp really fast with LOX augmentation.It is an interesting idea, though.
Fair enough - I guess it's a question of what you consider a "great" T/W ratio...
Quote from: jbrooks on 09/17/2011 02:42 pmFigure in the fact that increasing Isp has an exponential effect on your DV, and the benefits are even greater.It has an exponential effect on mass ratio, not deltaV.