NASA-backed fusion engine could cut Mars trip down to 30 days
Something is rotten in Denmark. If this project achieves a sustained fusion reaction as claimed, that represents a huge breakthrough, and not just for space propulsion, but for the general topic of fusion power.If it succeeds, it would sweep away all present fusion reaction prototype methods, including the well-tested but so far ineffective( * ) tokamak and laser-fusion approaches.* By "ineffective" I mean none of them has reached the break-even point, that point where more energy is released than is required to initiate the reaction in the first place.The article doesn't say whether the prototype device has actually succeeded in igniting a sustained fusion reaction. If it does, it would quickly move beyond its present goal of producing a more effective source of space acceleration and would answer some longstanding questions about fusion power itself.The fact that this isn't being discussed leads to my statement above -- something is rotten in Denmark. Either the  project is overselling its possibilities, and/or it can't really achieve fusion break-even.Speaking hypothetically, if the device could produce a sustained fusion reaction with substantial power, it could be scaled up and used to propel a spacecraft to Mars in much less than 30 days. Assuming a sustained acceleration of 1 g, the hypothetical craft could accelerate for 1/2 the trip, turn around and decelerate for the other 1/2 of the distance, arriving at Mars with zero velocity. Apart from minimizing travel time, this hypothetical profile would prevent the bone loss that accompanies sustained time at zero-g.Making the above assumptions, and assuming that Mars is at a close approach point in its orbit, the travel time could be as little as ... wait for it .. 50 hours.Derivation:1. Distance d (meters) for acceleration a (m/s^2) and time t (seconds): d = 1/2 a t^22. Time t for distance d and acceleration a, assuming 1/2 acceleration and 1/2 deceleration: t = 2 sqrt(d/a)3. Result for Mars close approach (7.834e10 meters) and acceleration of 1 g: 49.64 hours.Again, speaking very hypothetically. I still think something is rotten in Denmark.