Falcon Heavy, a history in making on the 6th of February.

The biggest and baddest is all set for launch on Feb 6, 2018! (Well, after 7 times of rescheduling, but hey, I am definitely very excited!) From LC 39-A at the Kennedy Space Center towards which all eyes will be directed to on the big day! So what makes this so amazing and sets it apart from the existing lifting rockets?

A two-stage super-heavy lift launch vehicle with 27 Merlin engines capable of generating more than 5 millions lbs (~23 MN) of thrust force.

Stage 1: Three adapted  & trusted Falcon 9 cores, with (9*3=27) Merlin 1D Engines.

RP-1 Source:Wikipedia

Arranged as one center core and two side cores/boosters, the first stage is very powerful. Each current version of Merlin 1D engine generates about 0.2 million lbs (~900 kN) of thrust from combusting Liquid Oxygen(LOX) and highly refined kerosene (RP-1/Rocket Propellant-1 pictured here). Now take a second to visualize the blue colored ones that we normally use, because I have always liked their strong distinct smell (LOL!). So rocket cognoscenti’s usually measure the efficiency of the engine with its specific impulse Isp and Merlin 1D’s uprated version operates at a sea-level specific impulse Isp of 282 seconds and vacuum thrust to weight ratio of 180. It can be argued that from this figure that it doesn’t seem to be quite efficient, but for an open gas generator cycle engine, Merlin 1D sure does leads. (And because of this Isp is why 27 engines are required in the Falcon Heavy). All Merlin family engines use a dual-redundant pyrophoric igniter, which contains a spontaneously combustible liquid (like Triethylaluminium). Its a cool apparatus which negates a lot of issues that might affect the engine performance (More info here). The first stage will provide the necessary escape velocity for the vehicle to escape earth’s gravity and will finish its purpose, handing over the responsibility to the second stage which will operate in the vacuum of space. 

Stage 2: A single Merlin 1D Vacuum. Why is a vacuum version necessary?

SpaceX Merlin 1C Engines Source: SpaceX

Lets revise our Rocket Propulsion 101 – optimal nozzle expansion ratio. Within the Earth’s atmosphere, we are limited by the condition that maximum thrust occurs when atmospheric pressure is equal to the nozzle exit pressure (Pe = Pa), but in vacuum, we don’t have this limitation and we know from the thrust equation that bigger the nozzle, higher the thrust. (More info on rocket nozzles here.) So the Merlin 1D Vacuum has been designed to have a nozzle which has an expansion ratio of 165:1 (7 times higher than the 1D variant). Here is a picture for comparison, the two engines on the left (Merlin 1C) operate at atmospheric pressure and the one on the right (Merlin 1C vacuum) operates in vacuum with a much bigger nozzle expansion ratio.

Lets not forget that all these three cores with four extensible landing legs

First ever Falcon 9 landing. Source: SpaceX

will make their descent back to earth and land safely on ‘Of course I Still Love You’. One thing to note here is that SpaceX engineers struggled a lot to put the Falcon Heavy together, meaning integrating the three cores and the 27 engines. Kudos to the structural engineers for arranging the engines in what they call the “Octaweb” configuration. (Its pretty genius, though not much technical information is available on this. I will write another article focused on this because, the arrangement gives the nozzle an ‘aerospike’ effect which I used to work on before 2 years which again has to do with optimal nozzle expansion). Also, carbon fiber and aluminium composite structures have been used extensively in the manufacturing of the Falcon Heavy along with state-of-the art manufacturing techniques. And guess what that results in?

“Lowest Space Launch prices in history, <$1000/lb”

Moving on to the fun facts,

The privilege of being the first payload to space through Falcon Heavy goes to Musk’s own Tesla Roadster. Look at this red beauty!!!

Tesla Roadster en route Space. Source: SpaceX

Also, here is an amazing video of the brief roaring for about 12 seconds of the Falcon Heavy (aka full scale static firing) on Jan 26, 2018 at NASA’s Kennedy Space Center. In Indian terms, a full-fledged Diwali experience from the 15 seconds mark.

Now that the government shutdown and more issues seem to have been solved, I am looking forward to a successful launch this week! Cheers~


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