Block 5. The elusive final iteration of SpaceX’s Falcon 9 rocket is finally almost here. Although we’ve known quite a bit about what’s going to be new with block V, the general public has had a very hard time understanding what, when, why, how, huh’s of block changes.
Well today, we’re going to try and untangle the confusion of the block changes, revealing the history of the Falcon 9 and how its evolved into the fully and rapidly reusable rocket we hope to see with this new ultimate Block V Falcon 9.
We’re also going to do a side by side comparison of all versions of the Falcon 9 including block V to show you just how much is changing before SpaceX commits to freezing the Falcon 9 so astronauts can finally ride on top.
And lastly we’re going to explain why SpaceX has been throwing away some of their older Falcon 9’s before they get into this new block V booster.
Ok. Time to do some untangling, let’s get started!
Today we’re going to take a deep dive into the world of the Falcon 9, how it’s changed and what this ultimate block V version means for SpaceX and hopefully the space industry as a whole.
Previously, we’ve talked a little about how the break-neck evolution of the Falcon 9 had led to the Falcon Heavy being delayed by 5 years, and we’ve also talked about how the nimble design and iteration philosophy of SpaceX has led to the cancellation of propulsively landing of the Dragon capsule.
So if you still have questions remaining after watching this video, check out those other two videos to potentially help fill in some gaps.
So first off, what the heck is a block? A block is a large solid piece of hard material, especially rock, stone, or wood, typically with flat surfaces on each side.
SpaceX sometimes uses the term block as an iteration change of their vehicles. This comes from the iterative and incremental development principle.
One of the earliest examples of this principle is with NASA’s project Mercury and the Army’s redstone rocket, both of which had small design tweaks as they applied lessons learned from each flight.
In terms of engineering and manufacturing, it means you’ll do small iteration changes to improve upon what you’ve learned, and once you make changes to the production line, that’s considered a block change.
There’s trade offs to this design philosophy. Some cons are the fact that there’s more prototyping and more changes to manufacturing, which can be more expensive.
This is the opposite of the “if it ain’t broke don’t fix it” philosophy that’s typically adopted by the aerospace industry. The idea that you don’t introduce any new variables because new variables can lead to new, yet unknown failures. SpaceX knows a thing or two about this.
Elon Musk has been known to embrace failure stating in a 2005 interview with Fast Company on the topic of SpaceX – “Failure is an option here. If things are not failing, you are not innovating enough.”
BUT, this philosophy also means the product can evolve to be more current, fluid and potentially much more capable. This is the reason why the Falcon 9 has evolved to be over twice as capable as its initial version and also why it can do that thing that no other rockets can do… what’s that.. Oh yes. LAND.
So before we try and untangle the mess of the block names, let’s go through the history of major changes of the Falcon 9 and compare them to the newest ultimate version, block V… this will help us be on the same page when we try and get to the cluster-turd mess of block change nomenclature.
The first Falcon 9 launched on June 4th, 2010 out of Cape Canaveral’s SLC-40. This first Falcon 9 was a baby compared to today’s Falcon 9. Standing at 47.8 meters or 157 feet tall, this first version was much more stout than it’s newer siblings.
It was also much less powerful, delivering 4,940 kN or 1.1 million pounds of thrust. The first version of the Falcon 9 was powered by SpaceX’s Merlin 1C, which is a lot less powerful than today’s Merlin 1D.
Besides the fairly obvious differences like height, lack of landings legs and grid fins, there’s one more thing that makes it easy to spot the first version of the Falcon 9… Those 9 Merlin 1C engines were configured in a square pattern as opposed to what we’re used to seeing today, the octagonal cluster known as the octaweb. We’ll talk more about that in a second.
This first version of the Falcon 9 only flew five times with its last launch on March 1st, 2013 carrying a Dragon capsule to the International Space Station for CRS-2.
A little more than 6 months later, we got the first launch of an upgraded Falcon 9, sometimes called v1.1, on September 29th, 2013. This was also the first launch from SpaceX’s west coast launch site, SLC-4E at Vandenberg Air Force Base.
This second version grew substantially to 68.4 meters or 224 feet tall, which is up a whopping 40% or so from its previous 47.8 meters or 157 feet tall. It has however remained the same diameter at 3.6 meters or 12 feet wide.
Perhaps the biggest upgrade to this Falcon 9 was in thrust. Due to the much upgraded Merlin 1D engine, the Falcon 9 was now producing almost 30% more thrust, achieving 5,880 kN’s or 1.3 million pounds of thrust.
This second version introduced the new octaweb layout of the 9 merlin engines on the first stage.
SpaceX changed to an octaweb design so they could just machine the same 8 pieces to hold onto each engine instead of needing separate corners and edge pieces, allowing for easier and more common manufacturing as well as easier installation of the engines with more commonality.
But perhaps the biggest and most exciting change this new version of the Falcon 9 introduced was the hardware necessary to land the first stage.
Due to the increased performance of the Falcon 9, it was now capable of putting its payload into orbit, and have enough fuel remaining to land the first stage using its engines to come to a controlled touchdown.
Besides SpaceX doing a few tests of supersonic retropropulsion: IE firing its main engines into the oncoming atmosphere at supersonic speeds, they also started to play around with trying to softly land the first stage in the water.
But the most obvious addition was on CRS-3 which launched on April 18th, 2014. This was the first rocket that featured landing legs. Something that people genuinely laughed at. Trust me, I was there!
My first ever launch was CRS-3, and to me, I was so excited to see a rocket with landing legs! How inspiring and amazing I thought. But other people who were at the press site were literally laughing at the concept, saying it was just impossible and clearly a waste of time.
Later SpaceX added grid-fins to the interstage portion of the rocket in order to be able to precisely control descent through the atmosphere. They first appeared on CRS-5 which launched on January 10th, 2015 and was the first attempt at landing on the autonomous spaceport drone ship, Just Read the Instructions.
Although they got close, no v1.1-ish Falcon 9 ever landed.
SpaceX continued to tweak and refine this version of the Falcon 9 until they experienced their first in flight failure of the Falcon 9 on June 28th, 2015 during the CRS-7 mission at T + 2 minutes and 30 seconds.
SpaceX stood down to find the cause of the issue and took this time to change over to the penultimate version of the Falcon 9, sometimes called v1.2 or Full Thrust.
The name’s kind of confusing, like that time SpaceX president Gwynne Shotwell called it that and more: “I don’t know what we’re going to call it. Enhanced Falcon 9, Falcon 9 v1.2, Full-Performance Falcon 9”
This upgraded version first flew on December 21st, 2015 with the historic OG2 launch out of SLC-40 at Cape Canaveral. The reason this particular launch is considered historic is because it’s the first launch that also had a successful landing of an orbital class booster. Something I couldn’t believe happened.
This version featured another healthy set of upgrades including enough additional performance to land the Falcon 9 from an even more energetic and crazy geostationary launch profile.
Some of the main changes is the Falcon 9 grew again, growing to 71 meters or 233 feet tall, and the thrust increased to a whopping 7,600 kN or 1.7 million pounds of thrust.
Most of this thrust upgrade was the result of SpaceX choosing to subcool the liquid oxygen and cool the RP-1 rocket fuel. This increases their densities, allowing more of each to be contained in the same volume and resulting in improved overall performance.
SpaceX also upgraded the landing legs, the interstage, the vacuum engine, the octaweb, the stage separator and a host of structural and weight saving changes.
But here’s where things get extra tricky. Since then, this version seems to be going through constant small tweaks here and there, including many things that will appear later on Block V.
One of the most obvious things we’ve seen pop up on a few of these v1.2 boosters are those awesome titanium grid fins, which are also super expensive considering they’re the largest single piece of forged titanium ever made.
But now, it’s time we throw in the newest and ultimate Falcon 9, block V.
For once in its life, the Falcon 9 isn’t going to grow any taller. It’s finally done with its growth spurts I guess.
That being said, it will however be SUPER easy to spot the difference. Block V features a very distinctive black interstage, black raceways those pipe looking things that run the length of the booster and protect the electrical connections and electronics. there’s also black landing legs and titanium grid fins!
This new version will feature another 7% upgrade to the thrust of the Merlin engines, bringing the total to 8,130 kN or 1.8 million pounds of thrust thanks to even more refined tuning.
The main purpose of this block V variant isn’t really to be more powerful, but it’s really just to apply all the lessons learned from the previous 50 plus launches of the Falcon 9.
For instance the rocket can now optimize it’s angle of attack on landing thanks to those awesome titanium grid fins and refined flight control system. Oh, and those titanium grid fins are super heat tolerant, and don’t require ablative paint and catch fire like the previous aluminum ones, meaning they can be reused over and over.
They also coated the entire vehicle in a thermal protective coating which should help limit reentry heating damage and they also made reusable and easily replaceable heat shields at the base of the rocket that help protect the engines and the plumbing.
The landing legs will now be able to be retracted allowing for easy shipping and rapid recovery. The previous landing legs actually had to be unbolted before they could ship each landed core.
All and all, Block V should be the final iteration of the Falcon 9, allowing for multiple reuses, and rapid turn around, hopefully even under 48 hours and no refurbishment. We’ll talk more about that in a minute…..
Ok… so now it’s time to let the untangling begin! Remember at the intro when I said “we’re going to try and untangle the mess with the blocks?” Well, I can officially say the deeper I got into this, the more confusing it got.
With the help of my Patreon members in our discord channel, we scoured every inch of the internet to truly find an answer. We checked the FAA fillings, the FCC filings, wikipedia sources, the spacex subreddit’s wikipedia, searched for every tweet with Elon or SpaceX talking about blocks or versions, every discussion on nasaspaceflight.com, countless sources and I can honestly say I’m more confused than ever.
I’m going to explain the two trains of thought real quick, One group of people think the Falcon 9 went like this:
Falcon 9 v1.0 or block 1, Falcon 9 v1.1 or block 2, Falcon 9 v1.2 Full thrust or block 3, block IV was testing out parts of Block V and then lastly Block V is it all put together.
Another set of evidence, and the one I actually think has more weight behind it is the following.
Falcon 9 V1.0. Falcon 9 V1.1 which actually had two blocks. Falcon 9 Full Thrust which actually had 5 blocks. The first block 1 full thrust was that OG2 mission and since then we’ve seen 2, 3, and 4 floating around and block V will be the fifth version of the full thrust variant.
And here’s my final conclusion on this topic. I don’t know. What I DO know is SpaceX doesn’t owe us any naming scheme. They have a lot of proprietary and internal information and there’s a good chance they don’t even have blocks or names themselves!
The way SpaceX tends to do iteration changes means they just simply might not have hard numbers or naming schemes and each rocket is almost unique as they evolve and are not beholden to simple layman block naming.
That being said, I have personally received multiple reports that Block V is the FIFTH iteration of the “Full Thrust” variant… And however we get to this point, tomato tomato, I’m happy to just call it block V and move on
So speaking of all of this rapid evolution and design changes, SpaceX is required by NASA to fly the Falcon 9 Block V 7 times without changing anything before it’s qualified for human flight. They’re calling it a freeze of the design. They don’t want SpaceX doing any tweaking that might lead to unforeseen incidents.
So expect things to settle down here for a bit. Besides that, Elon mentioned that now that Block V is the last major version of the Falcon 9, SpaceX plans to put all their engineering efforts into their upcoming Big Falcon Rocket or BFR.
Now lastly, we need to help explain why SpaceX has been throwing away rockets lately instead of landing them, even having grid fins and landing legs on some that are being expended.
Well remember that whole Block V is meant to be rapidly reusable thing? With Block V SpaceX hopes to be able to fly the Falcon 9 10 times without refurbishment. They hope to just do an inspection and then fly again with each booster capable of around 100 flights without requiring significant refurbishment. I really hope this is the case!
That being said, the non block V full thrust variants were never intended to be flown more than once or twice without significant refurbishment which means it’s not very cost effective to continue to fly them.
There’s a lot to take into account including the cost of recovery. When SpaceX sends the droneship out with a support crew, that stuff isn’t free. As a matter of fact, when you factor in gas, the support crew, the dock recovery crew, the transportation etc etc, it could easily add up to a million dollars or MORE.
With these rockets not being designed to refly more than once, it’s just an additional cost to go retrieve them.
There’s also the thought that SpaceX is expending these boosters to test the extremes of the vehicle, including maximizing how aggressively they can land and how steep their angle of attack can be as they reenter.
Data is valuable, and at some point, probably a lot more valuable than having another trophy piece collecting dust. And the only way you can truly test these aggressive reentry and landing profiles is with grid fins and landing legs to ensure that all variables are the same. A full dress rehearsal if you will.
Does that help clear the air at all? Or did I just make it whole lot more confusing. What are your thoughts? Are you sad to see the all white Falcon 9s die off? Are you looking forward to Block V and hopefully seeing it fly over and over again? Let me know your thoughts in the comments below!
In an upcoming video I’ll be comparing the Block V Falcon 9 with ULA’s Atlas V. A showdown of the two rockets that will be taking astronauts to the International Space Station hopefully by the end of 2018. Fingers crossed!
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I had a handful of additional help combing through so many documents looking for the best answer on this whole topic. So thank you guys for all your help and for keeping me sane!
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