Slashdot Mirror
SpaceX Signs Lease Agreement With Air Force For Landing Pad
PaisteUser writes Space News reports that SpaceX has signed a historic agreement to allow construction of a landing pad for Falcon 9 booster stages. From the article: "The U.S. Air Force announced Feb. 10 that SpaceX has signed a five-year lease for Cape Canaveral's Launch Complex 13, which was used to launch Atlas rockets and missiles between 1956 and 1978. In its new role, it will serve as a landing pad for Falcon 9 and Falcon Heavy booster cores launched from Florida, the Air Force said. Financial terms of the lease were not disclosed." Patrick Air Force Base also provides the documentation used for the environmental impact study which details out how the landing pad will be constructed.
Did you miss the part where it's already a launch complex? I.e. an isolated place designed for big-ass rockets packed to the gills with fuel to take off from? A landing accident would be much less of an issue than an accident during launch, and they've already demonstrated their ability to get the rocket to the bulls-eye once, despite severe mechanical problems. The fact that it crashed instead of landing is irrelevant to the safety of the distant population. Presumably by the time they've mastered actually landing at sea they will have a long run of "managed to hit the landing pad" under their belt.
Besides, it's not like they're planning to land them there today, and they're going to need lead time to actually design and build a suitable landing pad, etc. so that it's ready by the time the rockets are. It's not like you can just have FedEx deliver a landing pad overnight.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
fly all the way back to the launch site (would seem to be alot of fuel) -
That was my original impression, that you have to continuously burning to actively control the fall. But I recently saw a number that Apollo style capsul's terminal velocity is something around 300 miles/h and they spend several minutes free falling after fireball decelleration. Note "free falling" in this context is different from physical definition of free falling and describe the falling at constant speed of terminal velocity. 300 miles/h is half as fast as horizontal speed of airliners, and comparing to 120 miles/h of skydiving of human body (I'm a skydiver), it is not very fast. So after the supersonic reentry, I assume first stage is already on the trajectory to free fall toward the landing pad only controlled by the fins without any fuel burn. I'm curious what is the terminal velocity of the falcon 9 first stage is, but with empty large volume with little fuel left, and engine cones facing down, I imagine it is not that fast. This phase of landing is abbreviated in their fancy CG, so I too also got impression that they burn fuel from pretty high up, but we also saw one chase plane video of first stage coming down through the clouds without burning any fuel and seems to be in stable free falling.
To put it another way... the first stage has a dry mass of 18 tonnes but carries 385 tonnes of fuel, a 95 tonne second stage, and payload up to 13 tonnes. Hence for a given amount of propellant, the return leg of the journey right before flame out gets up to 27.4 times more delta-V. It makes it very easy to reverse your momentum. And of course, you don't need to reverse all your delta-V - for example, that spent achieving altitude or lost to air resistance. In fact, that spent achieving altitude actually helps you get back.
"That girl is a witch!" "Yeah, but she's our witch. So cut her the hell down!"