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.<p>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.<p>* 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.<p>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.<p>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.<p>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.<p>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.<p>Derivation:<p>1. Distance d (meters) for acceleration a (m/s^2) and time t (seconds): d = 1/2 a t^2<p>2. Time t for distance d and acceleration a, assuming 1/2 acceleration and 1/2 deceleration: t = 2 sqrt(d/a)<p>3. Result for Mars close approach (7.834e10 meters) and acceleration of 1 g: 49.64 hours.<p>Again, speaking very hypothetically. I still think something is rotten in Denmark.