Thanks Robert.

I was merely trying to dispel some myths that I sometime fear our friend vulture4 is a victim of. I too would like super-duper spacecraft looking better than a capsule. But “looking better” is not a mission requirement… Neither is “high lift”.

I think your points are some of the best on the subject and sorry if you took mine as disagreeing with them.

The PR videos are PR videos…there is no chance in my view that the reusable FAlcon “Looks” like the expendable one…which was my only point.

But I will bet this…a reusable Falcon launch vehicle is wider at the base for every stage, then it is at the top…and doesnt have wings RGO

There are a lot of issues even with a Delta Clipper shape related to the center of gravity for reentry. Delta Clipper never went beyond the transition to land stages and was intended as far as I know to enter nose first, probably at an angle of attack. In any case. My point stands.

FWIW Shuttle had a pretty big scare when they deflected the body flap on first flight I believe and it barely made it.

Again, don’t believe PR videos. They are after all only PR.

A reusable Falcon does not necessarily “look” Like the Falcon that is expended…the reusable Falcon can have more of “Delta Clipper” built into it…ie the shape…

you make good points RGO

For the DOD reusable launch program the situation is different. Since they have more money available and are working from the start to get the booster back, it makes more sense to start with a winged, subscale prototype with a suborbital up-and-back trajectory ending with a glide to a landing at KSC or CCAFS.

FWIW. You can get lift from a cylinder by flying it at a non zero angle of attack, other considerations such as structural loads on the first stage make it difficult if not designed with that in mind. Other considerations relate to the various components such as the nozzles themselves and other protruding in the air flow things. How much lift is determined by the mission you try to fly, nothing else.

The challenge they have is to reenter and fly back a booster that was designed for ascent. And that regardless of its ability to land nozzle first.

In that particular case lift is not their primary problem. Mission design actually is.

Again FWIW.

1. High L/D gliding flight with wings (X-15, Rutan Spaceship, Shuttle, X-37)

2. Low L/D gliding flight as a lifting body with terminal deceleration by pitcharound and rocket thrust (DC-X) or by releasing a parachute

3. Free fall with deceleration by parachute (Shuttle SRB)

Gosh, I must have wasted all those classes in engineering. A rocket engine is reasonably efficient as long as it is accelerating or decelerating, i.e. rapidly changing velocity. But there are two situations where the engine is pumping out thrust but velocity remains about the same, rapidly using up the available fuel. Drag losses occur when a rocket spends any significant time time at low altitude and high speed (e.g. horizontal takeoff) where the high air density creates excessive drag. Gravity losses occur when the rocket spends any significant time hovering or climbing or descending at constant speed, i.e. the impressive looking vertical takeoffs and landings demonstrated by several of the newspace companies. Unfortunately this strategy runs out of gas rather quickly.

There are (at least) four potential was around this problem. The rocket can be equipped with wings for a gliding entry and runway landing, like the X-15, X-37 or Shuttle. The rocket can have a low L/D lifting-body shape that can enter more or less horizontally at a controlled speed and use powered lift just before touchdown, possible by pitching up to the vertical just before landing (DC-X) or by releasing a parachute to maintain the constant descent rate until just before touchdown. If the rocket has no aerodynamic lift at all, the most fuel-efficient landing trajectory is still to do the fall freely at the aerodynamic terminal velocity until

The actual rocketback maneuver is reasonably simple and efficient by comparison, the “high mock” [sic] notwithstanding. Aerodynamics is a very minor consideration since the pitcharound where the booster turns end for end and flies nozzle first is done just after first stage separation, near the apex of the first stage trajectory where air is extremely thin, and propellant use is efficient since the rocket can use as much acceleration as it can structurally tolerate. The RTLS (return to launch site) that was always in the contingency planning for the Shuttle was a variant of this.

“The state of the art for this currently resides at Masten and Armadillo.”

I was merely pointing out that it is nothing new on its own. One might argue that Blue is trying for the same thing even though I have absolutely no idea how they all compare together.