Additionally Blue Origin says the BE-3 engine currently in use on their New Shepard sub-orbital vehicle (and intended as an upper stage engine for their proposed orbital launcher) has been designed with such uses in mind as well.

So there are several efficient paths forward for developing a reusable transportation architecture for cis-lunar space, extending from LEO to the Lunar Surface.

Now all that is required is the will to use them.

It is pointless to have these back/forth statements where you simply assert what I said is untrue, often misrepresenting what I said (one example – I did not say the Merlin’s were the Fastrac I said their design began with the Fastrac and it did).

Everything I said was factually accurate and anyone who wants to research the subject can confirm that fact.

Have a nice day.

1) No, the Merlin is not and has never been the Fastrac rocket. They did their own design and cut all their own metal. Both being crewed and being reusable was on the drawing broad from the start. This is not the same thing as saying the first flight article was such.

2) The pintle concept has a great deal of potential throttleability and the hover slam landings are dictated by available fuel, not throttling. The current Falcon has a dry weight of about 56,000lb and the Merlin can throttle to produce less thrust than this. When they have landed or attempted to land with more than one burning, this is because they had so little fuel they could spend no time hovering and needed minimize fighting gravity while reducing descent rate.

3) And the first launches were expendable, and developmentally paved the way for full re-usability. The first Saturns were not able to get to the moon, nor even conceived of being able to do so–but that was always the plan for the family (at least once the Nova was cancelled).

4) & 5) Parachutes were considered and discarded. It is not clear how that detracts from the notion reusability was not always a consideration. The more mass efficient use of engines and fuel already provided for won out.

It is as if you think the fact history is not planned out in perfect detail before hand means its an accident.

“They still have long way to go to make an economically viable reusable first stage, if they can manage it at all.”

The booster which will re-fly has already landed and I believe it was made years ago

“Therefore, your statement is factually inaccurate.”

Less so than your is. Your memory seems to be selective.

I remember hearing about the Falcons being intended to be re-usable 5 years ago and used for human access to space. This is not contradicted by the first several vehicles not meeting that goal.

I believe you are discounting the word, “iterative”.

NASA does not have to own the depot just control its development and interfaces. A COTS like scheme where it pays milestones during development and contracts to pay ‘x’ litres of fuel may work.

However, having written that LunarCATALYST and NextSTEP-2 (or -4) may do it.

“The Falcon 9 is already designed to be man-rated and reusable.”

(1) The Merlin Engines had their beginning in the government developed Fastrac Rocket, intended to be expendable.

http://www.nasa.gov/centers/marshall/pdf/100364main_Fastrac_Tech_Brief1.pdf

(2) As a result their throttling range is limited and that causes the requirement for the Falcon 9 first stage hard landing.

(3) I attended an early SpaceX briefing on what eventually became the Falcon 9 and at that time SpaceX described it as an expendable vehicle. They talked of the possibility of using parachutes to recover the first stage for examination (not reuse).

(4) Somewhere along the way that morphed into recovering the stage using parachutes.

(5) That then changed (again) into the current scheme.

I have great admiration for the line engineers working for SpaceX in that they have accomplished the landings at all. However they are in the process of trying to back drive reusability requirements onto an expendable vehicle (as I stated) in answer to Musk’s edict to “Make it so.”

They still have long way to go to make an economically viable reusable first stage, if they can manage it at all.

Therefore, your statement is factually inaccurate.

Marcel