Can /sfg/ tell me how I'm wrong with this, because I don't believe the numbers I came up with. I was looking at the Scorpion "hybrid arcjet" that combines a solid core NTR with an arc jet giving it these stats:
>Ev = 12,700 m/s (ISP = 1,300 sec)>Thrust = 2,000,000 N>Engine mass = 45,500 kg>Reactor = 14.6 GW with enriched U235I made a basic design rocket with an M/R of 1:1 who's wet mass would still allow it to accelerate at 9.81 m/s which came out to be 19,620,000 kg (2.9x mass of SpaceX ITS launch vehicle). With the propellant mass (LH2) coming in at 9,810,000 kg. The Delta-V finally came in at a solid 8,802.97 m/s (8.8 km/s).
The crazy thing I realized was the burn time this thing would have (this is a shitty linear equation that doesn't factor in the mass of the spacecraft losing mass as it burns through the propellant, so an actual number would be better than what I got). I assumed a mass flow rate of 30 kg/s as that is pretty typical of solid core NTR's. With that flow rate, I figured the rough highly inefficient burn time would come out to be 327,000 seconds....Which is 3.78 days of constant acceleration @ 9.81 m/s (1g)..... That's a Earth to Mars trip within 2-3 days kind of performance. That's practically torch drive, albeit at the low end, type of performance.
So what did I get wrong to get those numbers?
Source:
http://www.projectrho.com/public_html/rocket/enginelist.php 
