4 ms·
This is a common theory, but if you look at the math of the rocket equation, a very large percentage is for pure horizontal velocity, with a small percentage of
by xcskier56 4y ago
This is a common theory, but if you look at the math of the rocket equation, a very large percentage is for pure horizontal velocity, with a small percentage of gravity losses for getting from the surface to the orbital altitude, an even smaller percentage are losses due to aerodynamic drag.
I haven't done the math, but in general, the benefit of something like stratolaunch is much less than you'd expect
Here's a great (but complicated) reddit post on this topic:
https://www.reddit.com/r/KerbalAcademy/comments/63nzq6/how_do_i_calculate_delta_v_losses_due_to_drag/dg6peqy/?utm_source=reddit&utm_medium=web2x&context=3 https://www.reddit.com/r/KerbalAcademy/comments/63nzq6/how_d...
- dan_hawkins 4y ago"But getting to space is easy. The problem is staying there." - that's been an real eye opening read for me from fantastic "What If": https://what-if.xkcd.com/58/ https://what-if.xkcd.com/58/
- lmm 4y agoThe point isn't reduced drag. The point is to be able to do more horizontal acceleration with less propellant, because you're getting your oxidizer for free.
- jhgb 4y agoGetting something "for free" is hardly an issue since liquid oxygen is quite cheap as a percentage of launch costs (for example in case of Falcon 9, it's less than $100k out of ~$28M of launch costs for a reused Falcon 9). Now you might argue that the resulting vehicle that needs to be carrying needs to be bigger, but then again, in practice we found it less complicated than hypersonic air-breathing propulsion, so whether the vehicle capable of usefully consuming it would actually be cheaper is pure speculation. So far nobody has been able to build even just one, much less mass-produce it.