SpaceX plans to launch Transporter-6, its sixth dedicated small satellite ride share mission, from Space Launch Complex 40 at Cape Canaveral Space Force Station on Tuesday, 2023-01-03 at 14:56 UTC. The mission will launch 114 payloads for a variety of customers into a Sun-synchronous orbit. Falcon 9 first stage booster B1060 will be making its fifteenth flight, joining booster B1058 as fleet leader in missions flown, with landing back at Cape Canaveral LZ-1. Weather is predicted as 80% favourable for launch.
Interesting how things have gone full circle. As I kid in the ā50ās there were a few decent science fiction movies - even in color - which showed sleek, pointy-nose rockets landing upright on their fin tails. One I recall, even ācleverlyā rotated the interior crew quarters to account for gravity (I guess they didnāt yet know about weightlessness). Anyway, after real rockets got going, I figured it was impossible for such craft to land on their tails - as evidenced by the shuttle. Then, along came Elon Muskā¦
It probably was impossible until fairly recently. Navigating back to the landing pad requires accurate position information was would be very difficult to obtain prior to GPS, and then sensing vertical velocity precisely enough to perform a āhover-slamā or āsuicide burnā landing (since even a single Merlin engine cannot be throttled sufficiently low to allow the nearly-empty first stage to hover, it must start the burn at the exact time so that velocity is very close to zero at the time of touchdown) and requires instrumentation (my guess is that there is some communication from the landing site to the descending booster as it approaches) which would have been far too large and heavy to fly on a rocket (the Saturn Vās Instrument Unit, which had a far simpler job, weighed two tonnes, although that was in part because it was also a structural part of the Saturn V stack).
Vertical landing requires carrying more fuel than a winged glider, which uses the atmosphere to slow down and steer toward a runway, so at first glance it might be thought to be more efficient. But that doesnāt take into account the weight of the wings, flight control surfaces, and landing gear, which inflate the mass budget of the vehicle and reduce the amount of fuel it can carry at launch. The vertical lander already has the propellant tanks, engine, and guidance system it uses to land, so the only additional weight is the landing legs and aerodynamic grid fins, which are less than the gliderās components that are used only for landing.
Let me climb back on my hobby horse about the Path Not Taken ā the Delta Clipper Experimental (DC-X) which first launched & returned to its landing site in August 1993. That makes it almost 30 years ago. Thirty Years!
Yet despite that long-ago demonstration of a reusable rocket, the geniuses at NASA and the corrupt idiots in the US Government shut the program down. Where would the space industry be today if common sense had allowed that obvious opportunity to be seized?
No, it can and does deliberately start the landing burn later than that, so that the engine runs enough above minimum to have leeway for closed-loop adjustments to hit zero-zero.
