In   February   2018,   Space   X   launched   their   rocket   Falcon   Heavy   for   the   first   time   and   it‘s   now   the   biggest   rocket   in operation.   But   besides   being   very   powerful   the   most   interesting   part   of   this   rocket   is   it‘s   reusability   -   the   first   stage   and the   boosters   can   land   back   on   earth   using   their   engines.   To   test   this   new   rocket,   Space   X   decided   to   not   launch   a   satellite but   a   Tesla   Roadster.   The   live   stream   of   the   launched   was   watched   by   millions   of   space   enthusiasts   around   the   world.   The most   exciting   moment   was   -   besides   the   return   of   the   boosters   -   the   separation   of   the   fairings   (you   can   see   the   fairing separation   in   the   video   at   1:02).      The   amazing   footage   of   the   Tesla   Roadster   in   front   of   the   earth   made   us   wonder   if   we were   able   to   achieve   a   similar   moment   with   a   water   rocket.   And   so   we   decided   to   try   our   best   to   build   a   mechanism   which would allow us to separate the fairing and to launch a mini Tesla.

The   technical   most   challenging   part   of   the   project   was   to   make   a   fairing   which   would   act   the   same   way   the   fairing   on Falcon   Heavy   and   most   other   rockets   does:   The   fairing   consists   of   two   parts   which   are   separated   and   fall   back   to   earth.     Thus, it should be possible to recreate the footage of the separation a with our mini tesla.

From     the     very     beginning     it     was     clear     that     the     mechanism     would     be manufactured    using    3D    printing    because    this    project    is    difficult    to    realize otherwise,   as   the   fairing   halves   have   to   fit   very   closely   together.   We   already   had experience   in   developing   3D-printed   parachute   systems   at   that   time,   so   we knew   roughly   what   to   do.   During   the   design   process   we   found   out   that   the separation   of   the   fairing   can   be   combined   very   well   with   the   ejection   of   a   probe or    a    CanSat.    With    the    Earth    Observation    Water    Rocket,    we    have    already successfully   ejected   a   small   CanSat   in   2017,   which   collected   separated   from   the rocket   various   environmental   data.   At   that   time,   however,   the   mechanism   was vulnerable   and   required   a   lot   of   preparation   time   before   the   probe   could   be started.   Our   experience   with   the   3D   printer   has   enabled   us   to   make   such   a mechanism   much   safer,   more   flexible   and   easier.   So   we   decided   to   launch   our mini-car   with   a   detachable   probe   -   this   means   that   the   Tesla   returns   separately from   the   actual   rocket   on   the   parachute.   The   advantage   of   this   system   is   a longer   flight   of   the   Tesla,   better   possibilities   for   the   camera   placement   at   the rocket   and   of   course   that   our   newly   developed   system   can   also   be   used   for other purposes than the launch of a toy car.

19th June 2018

Rocket adapter

Probe with Tesla

Fairings

Is   mounted   on   the   rocket   and holds      the      probe      and      the fairings   in   position.   The   Tommy Timer   or   Servo   is   attached   to this part.

In   this   case,   the   probe   consists of   the   Tesla   and   a   casing   for the   parachute   and   an   onboard camera.

The      fairings      are      hold      in position    with    a    rubber    band, which      is      wrapped      around them.   There   are   little   hooks   on the     outside     to     prevent     the band from slipping.

Four   months   after   the   launch   of   the   Falcon   Heavy,   on   17th   June   2018,   we   were   finally   ready:   On   our   72nd   launch   day   we launched   the   Payload   Fairing   Mechanism   together   with   the   Tesla   onboard   the   modified   Arrow   2   rocket.   This   modified version   of   the   rocket   weighs   more   than   900g   at   launch,   as   it   has   two   onboard   cameras   in   addition   to   the   mechanism   and two   parachutes.   Besides   slight   wind   heights,   the   location   of   the   launch   site   in   Lampoldshausen,   which   was   surrounded   by high   corn   fields,   made   launch   conditions   difficult.   For   this   reason   we   decided   to   tie   the   Tesla   to   the   rocket   with   a   10m   long cord so that it would not get lost together with the onboard camera. We   launched   at   14   bar   /   200   psi   and   the   rocket   flew   straight   up,   where   the   fairing   mechanism   ejected   the   Tesla   as planned. Both the rocket and the Tesla landed at a shorter distance than expected from the launch pad.