With the change at the 6th launch from the original Falcon 9 design for the first five launches, to the new design, either called Falcon 9 v1.1 or Falcon 9R, it would be useful to understand the changes made.

It is also not entirely clear (at this time) if the v1.1 config is the F9-R config, or if they are two different models.

Additionally, how do the side boosters on the Falcon Heavy vs the core booster on the Falcon Heavy relate?

It is clear more than the public info is of interest.


1 Answer 1


There is a great summary article that reviews the various versions with changes in each version described and referenced.


Length of booster core

Here's an image showing the two Falcons side-by-side:

enter image description here

As you can see, Falcon 9 1.1 is much longer than its predecessor, Falcon 9 Block 1 had a liftoff height of 53 meters, versus Falcon 9 1.1's 69.2 meters. The stretch is to accommodate the additional fuel and oxidizer needed for the new more powerful engine.

Engine in use

The engine was changed from the Merlin 1-C to the Merlin 1-D which has higher thrust at 145,000 lbs at sea level. It is also reputed to be more easily manufactured.

Engine layout

The engine layout has changed. It changed from a 3X3 grid (tic tac toe) layout to the Octo-web layout of eight engines in a cirle, with a ninth in the center.

Landing Legs

With the Jul 2013 update of the SpaceX web site, the Falcon 9 v1.1 has been pictured with landing legs. This is for the Reusable part of the F-9R moniker. Tweets from Elon Musk have suggested that they will also act as aerodynamic surfaces of some kind during descent.

Additional statistics

Here's some more statistics in chart-ish form, from near the bottom of this page:

enter image description here

  • $\begingroup$ Thanks. I knew that part. I was sort of wondering if there was more info, but this is a great start for how it can be improved as more info comes available. $\endgroup$
    – geoffc
    Jul 19, 2013 at 21:03
  • 1
    $\begingroup$ The Merlin 1-D is also tested to over 10 full missions of accumulated burn time, which is more than the 1-C can. Note also: most of these changes are being kept in parallel to the Falcon Heavy (formerly Falcon 9 Heavy). spacex.com/press/2013/04/13/… The F9v1.1 is an intermediate step to the 9R; spacelaunchreport.com/falcon9v1-1.html $\endgroup$
    – aramis
    Aug 2, 2013 at 9:12
  • $\begingroup$ The landing legs are supposed to act as aerodynamic spin stabilizers on descent of the 1st stage, basically to prevent aero torque problems that the 1st stage had during the first Falcon 9 1.1 flight. At least that's the gist of it based on tweets by Elon Musk. Anyway, second launch is just a few days away with its SES8 comms satellite mission to geostationary transfer orbit, so the 2nd stage will have to work flawlessly too, and I guess we'll see about the 1st one. $\endgroup$
    – TildalWave
    Nov 22, 2013 at 21:06

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