Talk-Polywell.org

A brainstorming thread, various methods for dealing with less than ideal weather at a space launch / stage recovery site. If we are to become a truly spacefaring society we need to bring down both cost of space launch and delays.

A first thought: Horizontal vs. vertical launch and landing with winds. Airliners routinely take off and land with cross wind speeds that we hear about delaying rocket launch. Is this an advantage of horizontal take off or a reflection of a more mature technology?

Crosswinds that can cause a rocket to go unstable are the most concerning at takeoff, since the instability of the rocket is determined by the angle of attack of the rocket to the wind. Especially when the rocket is at very low velocity in its first moments flight, the vector addition of the rocket's velocity and the crosswind can yield angles that are unsafe. The Falcon 9 for instance, generates a low acceleration with fully loaded tanks: 1,100,000 lbs thrust/ 735,000 lbs mass. This leaves it vulnerable during the first few seconds. Rocket stability is also contingent upon the changing distance between the center of pressure and the center of mass, as the tanks empty. This turns it into a complex issue but that you can find explained here:

http://www.apogeerockets.com/Wind_Caused_Instability

Horizontal launch is safer, but so much less efficient that I don't think anyone takes it seriously anymore. Simply put, for craft to operate like modern commercial aircraft, you can't use rockets. They're just not safe and will never be.