> This is the primary reason for selecting the annihilation of a proton (p+) and antiproton (p–-); the products include neutral and charged pions (πo, π+, π-),

> This is the primary reason for selecting the annihilation of a proton (p+) and antiproton (p–-); the products include neutral and charged pions (πo, π+, π-), and the charged pions can be trapped and directed by magnetic fields to produce thrust. However, the pions produced in the annihilation reaction do possess (rest) mass (about 22% of the initial protonantiproton annihilation pair rest mass for charged pions, 14% for the neutral pions), so not all of the protonantiproton mass is converted into energy. This results in an energy density of the proton-antiproton reaction of "only" 64% of the ideal limit, or 5.8x1016 J/kg. I love that someone wrote and published a serious paper where the end design involved first stage thrust of 550 million ft-lbs and the total ship weighs something like 17 million metric tons and if I'm reading page 26 correctly, the payload on the ship has to be 7,500 kilometers from the ignition source to survive. https://www.relativitycalculator.com/images/relativistic_photon_rocket/ANTIMATTER_ROCKET_FOR_INTERSTELLAR_MISSIONS.pdf https://www.relativitycalculator.com/images/relativistic_pho...