BFR is SpaceX's large rocket project. The launch
vehicle consists of the booster Super Heavy and an upper stage called Starship,
which is also intended to serve as a spaceship. Both stages are powered by Raptor
engines. The declared goal is the development of a fully reusable carrier system
for a payload of over 100 tons.
On September 29, 2017, Elon Musk presented his rocket concept called BFR (Big
Falcon Rocket) for the first time at the 68th International Astronautical Congress.
Since then, the design of the rocket has changed several times.
Booster stage (Super Heavy)
The first stage, known as Super Heavy, is now to be equipped with 33 Raptor-2
engines. An inner group of 3 engines would be swiveling mounted and would provide
thrust vectoring. The approximately 70 m high stage with a diameter of 9 m is
to land on the launch pad after separation. SpaceX wants to try to land the
stage in a catcher right at the launch tower on the launch pad.
The original planning called for carbon fiber reinforced plastic (CFRP) for
the load-bearing structure and the tanks. From the end of 2018, a switch was
made to a stainless steel construction.
Upper stage (Starship)
For the planned engine design of the Starship upper stage, SpaceX decided to
use six Raptor engines, 3 of them identical to those of the first stage and
3 vacuum-optimized engines (later 6 engines ?). As with the Super Heavy, thrust
vectoring is provided for the inner ring of three swiveling mounted engines.
As with the the Super Heavy, the tanks evolved from a CFRP design to a construction
of welded together sheets of stainless chromium-nickel steel. The outer hull
of the Starship is to be covered with thin ceramic heat protection tiles.
In contrast to conventional rocket designs, the upper stage is firmly connected
to the payload section. The total length is 50 m.
The Starship has four lateral wings as control and landing aids. Two small wings
are attached to the top of the spaceship, two larger wings are attached to the
The upper stage is planned in at least six different versions: freighter for
large payloads, as a tanker, as an orbital fuel depot, as a spaceship for passenger
and cargo transport and as a lunar module.
A first launch of the BFR system is planned for summer
2022. The Booster BN7 and the Starship SN24 are to be used for this. Both stages
will already be equipped with Raptor-2 engines. The risk of a successful orbital
flight and subsequent landing is great, because there have been no flight tests
of the newly configured stages.