SWM wrote:Kytheros wrote:D'you have a quote for that? All I remember is that downwards translation is specifically called out as bleeding away velocity, but nothing about upwards translations, at least from the books, upwards translations might get specified in one of Weber's infodumps.
From The Universe of Honor Harrington, published in More Than Honor (emphasis added):The major problem limiting hyper speeds was that simply getting into hyper did not create a propulsive effect. Indeed, the initial translation into hyper was a complex energy transfer which reduced a starship's velocity by "bleeding off" momentum. In effect, a translating hypership lost approximately 92% of its normal-space velocity when entering hyper. This had unfortunate consequences in terms of reaction mass requirements, particularly since the fact that hydrogen catcher fields were inoperable in hyper meant one could not replenish one's reaction mass underway. On the other hand, the velocity bleed effect applied equally regardless of the direction of the translation (that is, one lost 92% of one's velocity whether one was entering hyper-space from normal-space or normal-space from hyper-space), which meant that leaving hyper automatically decelerated one's vessel to a normal-space velocity only 08% of whatever its velocity had been in hyper-space. This tremendously reduced the amount of deceleration required at the far end of a hyper voyage and so made reaction drives at least workable.
Thanks for digging up that quote (and Vince as well). I'd remembered that it was mentioned in relation to the pre-impeller hyper-capable scout ships -- but not where that discussion existed.
But the velocity drop on upwards translation doesn't really impact the books; so it basically never gets mentioned. Probably because ships mostly transit right up to their 'cruising' hyper band before building up much velocity. (Who really cares if you lose 70% of the velocity you built up while your hypergenerator recharges when you're going to be accelerating for hours to build up to your max safe speed)