Thursday, November 28, 2013
Friday, November 22, 2013
7:13 PM (10 hours ago)
I sent this to Bill Douglass. Is it OK, is it clear? This is basically what I want to say. I hope to help get the first stage back safely to the their landing pad. The Draco is the 18 attitude rockets for both Dragons, and the 8 Super Dracons are also the Launch escape, and landing rockets for the Dragon Rider.
I see two problems that SpaceX is having with getting the first stage of the Falcon 9 quickly and safely returned to the original launch pad.
I believe one problem is that the fuel is not settled to the tank output to reliably feed the engines when they need to be restarted after the second stage separation. This leads to the second stage not being able to turn around quickly and using much more fuel
The gimbals system is wonderful for launching. I believe it is the only way the Falcon 9 first stage can currently affect control. After the tank is nearly empty the center of gravity is close to the engines and is pointed in the wrong direction. To make matters worse even at max gimbals almost all side or horizontal components of the forces end up in a side movement instead of an angular movement making it difficult to turn around. Using just gimballing takes lots of fuel accelerating in the opposite direction we want it to go, then that much more fuel is needed once we are finally turned around and going the way we want.
I suggest adding one or two Super Draco rockets and between two and four Draco attitude rockets mounted at a forty five degree at the top of the first stage. This would enable a quick turn around using very little fuel. Also a few seconds burn of the Draco attitude rockets can settle the fuel to the bottom of the tanks enabling restart.
I hope you will take these thoughts into consideration. I believe this could solve those two problems.
Tuesday, November 19, 2013
Tuesday, November 12, 2013
Sunday, November 10, 2013
Monday, November 4, 2013
November 4, 2013 7:06 am
India shrugs off criticism to prepare for launch of Mars mission
By Victor Mallet in New Delhi