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Why does SpaceX keep changing the BFR? The evolution of BFR

Why does SpaceX keep changing the BFR? The evolution of BFR


– Hi it’s me, Tim Dodd
the Everyday Astronaut. It’s fall of 2018 and you know what time fall is, it’s BFR time. That’s when Elon Musk
is going to update us all on SpaceX’s plans to going to Mars with their big Falcon rocket. Now last year they changed
quite a few things on us. So this year we’re going
to find out what’s new here at SpaceX headquarters,
I’m going to go inside I’m going to learn and listen with my ears and then we’re going to come outside and I’m gonna tell you about what changed and all the
big details and speculate on all the other fun things. So let’s get in there,
let’s learn some stuff. (smooth music) – We are inside SpaceX’s
headquarters, this is where they action manufacture
of the Falcon nine rocket and notice behind me is the
actual Falcon nine that’s being worked on and there’s
another one over there, but here’s the crazy thing. Look how much bigger
the BFR is going to be. That is insane and there
is a reason why they have to build those things out
on the port because they wouldn’t be able to get
that thing out this door. So yeah, I can’t wait for these details. Elon is going to be talking
in about 10 minutes. I better get going. (smooth music) – We have so much to talk about. Okay, I’m here at TMRO Studios to talk about what we just learned. The presentation wasn’t as
technical as I had hoped for. I really like all those
nitty gritty details, however it was incredibly inspiring, especially the opportunity
that Japanese billionaire Yusaku Maezawa is offering to artists, okay that actually made me tear up. So we can talk about
that or we can sit here and we can talk about cool things like the new reentry
system, and how the fins need to actuate in order
to basically belly flop through the atmosphere,
or we could talk about why does this stuff keep
changing every single year and talk about that evolution process. So I think that’s what
we’re going to do today. And then in future
videos I’ll get into some of those other things as well
because they are really cool. Okay first of all, let’s go
ahead and pop up all three versions of the BFRs we know it now. Now don’t forget in 2016, we
didn’t call it BFR publicly. It was called the Interplanetary
Transportation System, or ITS, so I might call it that sometimes but I might also just call it BFR. As you can tell it’s changed every single time they make an announcement. It used to be a 122 meters
tall then last year it shrank down to 106 meters tall, and now this year it’s standing at 118 meters tall. Now just for funzies lets
go ahead and compare that to the Saturn five, which was 110 meters tall and the Falcon Heavy,
which is 70 meters tall. Okay then there is the width. It started off at 12 meters
wide then last year it shrank down to nine meters wide,
which it still is today except for those folding
landing legs slash fins that stick out a little
bit more on the BFS. We’ll talk about that more in a second, but of course it is still
a little bit skinnier than the Saturn five, which
was 10 meters wide and it’s a lot wider than the
current Falcon Heavy cores or the Falcon nine cores
which is 3.7 meters wide. One think that we don’t
know too much more about is actually how many
engines are on the booster. So in 2016 it had 42 Raptor
engines and then when it shrunk down last year it ended up with 31 engines and since
the diameter is the same I’m guessing it will still
have 31 Raptor engines but that’s quite a few
more than the Saturn five which had five F1 engines
bit it’s not that much more from Falcon Heavy,
which has 27 Merlin engines. Assuming there’s the same number of Rapture engines on the Booster 31. Now Elon says each engine is
capable of 200 tons of thrust which is equal to 1,962
kilonewtons times the 31 engines and that means it will have
60.8 meganewtons of thrust. Now that up from last
year’s 52.7 meganewtons but that’s still way down
compared to the original aspirations of 128
meganewtons of the 2016 ITS. But then again it’s
all a lot more powerful than the Saturn five that
had 35 meganewtons of thrust and is about two and a
half times more powerful than the Falcon Heavy, that’s insane. So now payload capability,
this has changed a lot over the years,
initially ITS was capable of 300 tons to low earth orbit
and that changed last year to 150 tons and now we’re at 100 tons. So it’s shrinking but at the
same time 100 tons is still an insane amount especially
when you’re talking about fully reusing a rocket. Now of course the Saturn
five was capable of 135 tons to the low earth orbit but the entire vehicle was expendable. Then you have things like
the Falcon Heavy which is 90 percent reusable and
in that configuration it can only take about 30
tons to low earth orbit. So it’s a lot more capable
than the Falcon Heavy. So now we need to talk more about the BFS, the big Falcon ship or
the upper stage portion. This again has changed a lot. This probably changed the
most and Elon’s talked over and over again about how this
is going to take the most design work and the most engineering because it has to tackle
a lot of problems. Okay so easily the most
obvious addition is the fins. Now I need to be really clear about these. These are not wings, they
aren’t there to provide lift they’re more there to provide drag and increase the surface area. So think about these
more flaps or air breaks and less like wings. Elon mentioned this thing
reenters more like a skydiver does than an
airplane does and it does this by changing the amount of
drag basically on those flaps in order to provide control authority. So this is really important
because you actually want to bleed off as much
speed as humanly possible through the atmosphere
and this is a really, really good way of doing that. This is super different
from the Falcon nine, which reenters butt first
and it’s only going about a quarter of the speed of
orbital velocity and despite this it still needs to do a
really healthy reentry burn slowing itself down about half before it reenters the atmosphere so the atmosphere doesn’t destroy it. Now the BFS isn’t going
to try to lower its speed to one eighth using retro-thrust
that would be an insane amount of delta v fuel wasted. So instead it wants to use that
atmosphere to its advantage. Because the atmosphere can
remove almost all of the velocity of the vehicle
the trick is you want the atmosphere to do as much work as possible without destroying the vehicle. We’ll go way more in dept with
this crazy reentry system. Because it’s completely unique
in the aerospace industry. I’ve never seen anything like this. Meanwhile check up on my video title ‘Will Falcon nine be reusable
or just refurbishable,’ which goes into some of
the physics of reentry and talks about why you can’t
really compare a booster to an upper stage or spaceship. Okay now back to the BFS
and those fins real quick. Now those fins are also the landing legs, which is important because
they’re going to have the dry mass of landing legs anyway. That’s going to take away some
of the payload capability. But the thing is, you might
as well make it so they do other things like a lot
of people talk about when the Falcon nine
reenters why don’t they use the landing legs to pop out and they kind of work as air breaks. Well, that’s basically what this is doing. It’s using the landing
legs as air breaks so it’s almost like bonuses instead
of some kind of detractor. The engines on the BFS
has changed all the time. Initially in 2016, we saw six vacuum optimized rapture engines
and three sea level engines. Then last year it changed to
four vacuum optimized engines and two sea level and
then Elon updated it like three weeks later on Reddit
saying it’s actually three sea level engines and now out of nowhere we see seven sea level engines. What is the deal, well
someone out there had enough nerve to ask Elon Musk what
is up with this new design. – Hey Elon, Tim Dodd the
Everyday Astronaut here. I see that you changed the
engine configuration for the BFS. Can you talk a little bit
about it there still engine out capability, is it vacuum
optimized but still mandible on sea level can they function as an an abort system,
can you just tell us about your decision making on that. – [Elon] Oh yeah, that’s a
good thing to notice, good eye. – Oh shucks did you hear
that, someone has a good eye. But as someone with different
colored eyes now I’m unselfconscious about
which one is the good one. Okay, but this new seal
level only configuration is pretty confusing to me, last
year Elon talked over and over about how important it is to
have engine out capabilities for landing to minimize pucker factor. This new configurations
doesn’t seem to be too privy on engine out capabilities
for landing, or does it? So now if you look closely
the engines are really, really close to the center, which
is actually really good for landing burns cause Elon
did say they’re still planning to use three engines to land. Now say the outer engine would go out in the middle of landing. I think they’re close enough to the center that you could offset
thrust by gimballing enough to actually make it so the
vehicle doesn’t totally tip over. So I believe it could probably
still land on just one engine but the light three for
redundancy purposes. For now, we’re not going to see a vacuum optimized Rapture engine
and that’s pretty weird but honesty it’s because they can now streamline manufacturing and
just crank out one engine over and over, but also
because quite frankly, it might be good enough
with just sea level engines. The specific impulse of
the sea level engine or how efficient the engine
is, is about 330 seconds. Now that’s pretty good but
it’s not as good as 380 seconds they would be able to get out a vacuum optimized rapture engines,
which they could sport on later versions and they
might be able to kind of change out which kind of ship they use, depending on the mission needs. Now some of the nerdy details
of the Rapture engine. Is this is a full flow
stage combustion engine that burns methane and
liquid oxygen and has a crazy high chamber pressure of 300 bar. Let’s not go into the details
about what chamber pressure is right now but just to
compare how insane 300 bar is let’s look at some other engines. I believe the current king
of high chamber pressure is the RD-180 from
Russia which is 265 Bar. Then we look at the chamber
pressure of the RD-170 that Russia used on their Energia rocket, That was 250 bar, the RS-25
engine on the space shuttle was 206 bar, the space engine’s Merlin engine that they currently use are 97 bar and the F-1 engine on the
Saturn five was only 70 bar. So 300 bar is crazy. The last big change is the
internal cargo volume of the BFS. Now last year I believe
it was sporting 800 cubic meters and now
they’re looking at over a thousand cubic meters of cargo volume. This is interesting maybe
the team decided they’d rather have more internal
cargo volume than actual payload mass capability. Just one of those trade offs that might be valuable when you’re flying humans who require a lot of moving room
compared to just satellites. Another thing they added as AFT cargo. What’s AFT Cargo? Well it’s unpressurized
portions of the ship, kind of like the trunk from the dragon capsule and why would you want this? Well think about it, if you
land on another planetary body and you need to get
things like solar panels, you need to get fuel pumps
to make new fuel out of the atmosphere using in situ resource utilization or maybe you need a rover. It’s a lot easier if you have
to reach up from the bottom and put it on the ground as oppose to say having a cargo bay up top and unloading using cranes or something. It’s actually a pretty good idea. This is where having those
smaller sea level engines make room for those AFT cargo base. So then it’s a pretty
good compromise when it actually comes to practicality
and that’s almost where this whole thing comes together. There’s been a lot of big
changes to BFR and you might go why, why is it every
single year we see basically an entirely different
rocket, how seriously can we actually start taking this
stuff when every time we get a glimpse of it, it’s totally different. Well, Elon actually said
something extremely enlightening that gives us a really good
perspective on some of the problem-solving that goes into making a vehicle this groundbreaking. – [Elon] This is a stupidly hard problem, and SpaceX engineering, I think done a great job with this design. I don’t think most people
even in the aerospace industry, know what questions to ask. It took us a long time to even
frame the question correctly. But once we could frame the
question correctly the answer, I wouldn’t say was easy,
but the answer flowed once the question could be
framed with precision. And framing that question with
precision was very difficult. – Here’s where we maybe got
the biggest glimpse into SpaceX’s design process for the BFR. SpaceX is doing something
that almost no other aerospace company ever gets to do and that’s start with a completely blank canvas. Now I’m not saying this
has never been done before, but to not have some outside
requirements that kind of gets in the way of your physics lead design, is pretty unusual. You know, normally it’s like
we have this heritage hardware we need to use or
something, but in this case SpaceX is starting from scratch. And they can let physics do the talking. Look at the space shuttle for example. NASA had so many requirements
from so many different people when they had to design that thing, it was really compromised. The Air Force said we need the payload bay to be this big and to be able
to carry this much weight for our spy satellites they
also needed to be able to build the International
Space Station with it and carry up to eight astronauts. SpaceX doesn’t have any of those outside requirements when designing this. So instead, SpaceX gets to
first come up with a question of what does this actually need to do and how do we make it do that the best. And this could lead to
getting over some fears like Elon’s fear of wings because, “Wings are useless, in
space,” of course he’s right it’s just dead mass when
it’s up there in space but if they can scrub off a
lot of velocity and save you a lot of Delta V on reentry and landing, maybe they are worth considering. What we’re witnessing is
something incredibly unique I can’t think of any other
company that’s ever let you in on the design process. Can you imagine if Apple
is like, “Hey we’re working “on a new iPhone and show
you some tweaks along the way “before it comes out,” or what
if Lockheed Martin is like “Hey we’re coming out
with this new fighter jet, “and every year we’re going
to let you know what’s changed “in our design process
before it comes out.” That just wouldn’t happen,
so this is actually really exciting, we’re
watching the tweaking and the molding of a brand new rocket. It’s a really cool
demonstration of engineering. We’re actually getting to
see them tweak and tweak and tweak and make it better which is what engineering is you just often
don’t actually get to see it. So I guess the only real
question I have remaining at this point is will they
be tweaking the BFR once they start making it, kind of like
they did with the Falcon nine. So SpaceX basically never
made two Falcon nines the same because they are constantly
tweaking it, adjusting it making it better and
able to do things like oh I don’t know, land, be
recovered and then reflow. It’s something that’s
never been done before. Will they be tweaking the BFR constantly and making it better once they start? I’m sure they will, it’s SpaceX after all. And unfortunately those are
all the nitty gritty details we got this time, maybe
we’ll learn a little bit more when Elon does that
Reddit AMA I asked for, you’re welcome, how about
as a return favor let’s all get on Twitter and ask Elon Musk to do a sit down interview
with me, I promise I’ll ask all the good questions. While we’re talking about
favors, thanks to TMOR for letting me use their
amazing studio space here. If you guys don’t watch TMOR on YouTube, What are you doing? It’s the best space show period. That’s YouTube.com slash TMRO. They film every Saturday live at 18 UTC and you can join and have
your comments in the show. They have interviews,
the do up to date news, It’s just the best, so make sure and go to YouTube.com slash TMRO. But of course, I owe the
biggest and most sincere thank you to my Patreon supporters. If it wasn’t for you guys I wouldn’t be able to come out here
to California and cover things like this, I’m
from Iowa so getting out to California or down to
Florida for launches is really expensive and
I owe you guys so much thank you for financially supporting me. If you want to help me
continue to do things like this and get super nerdy
about all the space stuff Please go to Patreon.com
slash Everyday Astronaut. Seriously thank you, it
means the world to me. And while you’re on the
internet check out my web store. It has lots of cool stuff
like shirts and hats, mugs, prints of rocket launches
and lots of other fun, cool pictures Check it out
Everydayastronaut.com slash shop Oh and thanks to my friend Patrick Lawler, who helped shoot this event with me. I mean his stuff is just incredible. You should check it out,
he’s all over the internet. Thanks everybody that does it for me. I’m Tim Dodd the Everyday
Astronaut bringing space down to earth for everyday people. (smooth music)

100 comments on “Why does SpaceX keep changing the BFR? The evolution of BFR

  1. I think that is so cool how you have different coloured eyes. Love your content and you. Keep doing what your doing!

  2. Great job with the question, Tim. I usually cringe when "press" ask questions, but you're quite capable, obviously!

  3. Those are GREAT points about @spacex and how they LET US IN. A totally PRIVATE company, at that! Hopefully other companies will observe Elon's transparency and give us MORE details and info, instead of being "secret". That way, they can have all their ideas on video, and it would give their IP MORE protection, not less!

  4. Hey Tim. I think I have a brilliant idea for a video series. You should start a series of videos that show the different capabilities and missions that the BFR could do. You could start with a detailed look into SpaceX using BFR as a spacecraft to clean up Earth's orbits followed by talking about how Starlink and BFRs could be used then work onto bringing NASA into the picture on how it could use the BFR to launch the Deep Space Gateway and other exciting space stations out in orbit.

    Hell, maybe even try and bridge Star Trek with SpaceX! This'll be interesting. Hopefully this gets noticed by Tim Sampai (Fingers crossed).

  5. Space X keeps changing their designs because Blue Origin hasn't made an orbital flight yet…
    … and they don't want to be like them.

    Blue Origin has committed to incremental advancement. Something is done.. it's done to plan, it's done perfectly.. and then it's tested in infinitum until it meets the numbers it's supposed to.
    Space X stuck the parts together.. blew it up.. rebuilt it after figuring out what blew up.. got one that didn't blow up.. measured the thrust and weight… and built a rocket around that.

    Wash.. rinse.. repeat.
    It's said that no two rockets that Space X has ever built have been the same… until this most recent iteration of Falcon 9.

    In the immortal words of agent Smith… "One of these lives has a future… the other… does not".

  6. Every new problem solved creates a new problem. So you have to adapt and change according to the latest findings.

  7. I just saw this. You did a really good job at covering that. Elon wasn't doing his best speaking that day. I enjoyed your presentation much more.

  8. The coolest rocket scientist I've talked to is Peter beck. The leader of new Zealand rocket lab. He designed the electron rocket. I video chated him, with the rest of my production class. I was honoured he said yes and we all had a good conversation. And I'm only 13. Greatings from a tiny town in New Zealand.
    Im exited to see the finalised bfr. But it may take a long time to design,since we haven't. Ade anything this big before, and never, ever, have we sent something this big to orbit, let alone, mars. But, knowing spacex, and Elon musk in particular, we ain't givin up!

    Plz reply!

  9. I wonder if Elon has considered 3D printing a landing pad out of the Mars regolith.

    Would it be possible to print a pad with rovers?

    Something large enough to land a rocket.

  10. hey everyday astronaut i want to grow up to be an attorney at private practise and be the lead archetectual designer or mechanic of the space x rockets thanks for being here with all of your videos

  11. Because anyone that's done something extremely difficult knows what you're taught to believe isn't actually enough, and you'll learn more than you knew.

    It's not actually complicated, just unimaginable to the mindlessly obedient to emotional support for a reward.

    The Junkyard Dog doesn't care why you're their, they only know you're not allowed.
    Doesn't pay well but, you get to feel in charge without much consequence you'd fail to appreciate or survive. Seems like a good deal, until you think about it.

  12. Hi Tim, after seeing your studio back drop I've 100% decided on how to decorate my kids bedrooms! (maybe even mine and the wifes bedroom – TBC)…. I want control panels, blinking red blinkers and buttons with sound effects BUT where the hell can I find / buy those window panels from with the Earth scene lightboxes behind them…  The kids would pass out with excitement !!   Love watching your video's, cheers Tim!

  13. Just wanted to say that "The Scale Of It All" is a great track, and that I had no idea that you made music as well as being an amazing science communicator. Great work!

  14. Well they want to be able to resue a BFR 5 times right? So on the 5th launch of a booster they could do an expendable launch which could maybe get you to 150 – 200 tonnes to LEO.

  15. Comparing interplanetary rockets with suborbital rockets? why? Also, americans using pounds and feet… seriously? lol

  16. Love the video. Dude your ears are aerodynamically out of whack. Nothing wrong with that, just thought you should appreciate that along with your eye thing. Back to rocket design; especially landing boosters for re-use. I really think it is unwise to land standing up. Landing should be a two step operation where once you stick the touchdown; you immediately lay down horizontally and not remain vertical, which is most unstable. This technique almost designs itself. Two – four lay-down boosters: two to control laying down into the wind and two for actually easing the lay-down that are 180° apart. You need enough thrust for about a 20 second transition thrust. Extra legs 3/4 of the way up the booster to carry the mid-load.

  17. RD-180. Atlas V (USA Using USSR/Russian Engine?) Союз нерушиый республики свободных

  18. I came up with Elon's follow up to the BFR

    Take three BFR, and put them side by side like the Falcon Heavy. Then put a full BFR on the center core.
    The Stupid Falcon Rocket

  19. I really dont know if you are Genius or nerdy about Rockets, but i can say i have seen the realtime example of "Enthusiast". I can see the enthusiasm in all the presentations 🙂 The way you present information just reaches our mind with happiness 🙂 not just knowing 🙂

  20. I'm very skeptical of the BFS, or BFR or whatever you want to call this upper stage.

    "framing the question was difficult, but then it flowed" …. I see, so what was the question ??

    Please correct me if I am wrong, but the BFR only exists as CGI at the moment …

  21. They aren't concerned about sea-level or vacuum optimized engines because they've sorted out variable expansion nozzles. You'll see it in a few months.

  22. 10:50 for comparison most cars that are tuned with a Turbocharger and then run about 2 to 3 bar which is around20-30 to 40 PSI

  23. Carlos Encarnacion: I love this project. Since it would take around six months to arrive Mars I wonder and think that habitable zone area within such ship inside wall should have at least a 3/4 feet wide size empty compartments protruding from inside surface matching space ship curved design that could be occupied with non flammable bags containing sand and rocks or any other radiation protecting materials to protect astronauts from short wavelength radiation that would harm them on the long run during such long trips until new thrusters technology arrive in the future to shorten such trips. Consider that astronauts efficiency and performance might be affected in Mars as a result of such long trip short wave length exposure and we don't know potential outcomes .Once there underground structures, caves or new technological advances could solve such situation permanently. Those compartments once occupied by rocks and sand bags inside would have the other habitable space structures within space ship above them. If installed before they would add weight and cost during lift off. If lifted in a compartment closed to tanker surface during refueling through pressurized hatch openings giving access to both tanker and habitable space ship inside once in orbit protecting material could be transfer manually and put inside the wall empty compartments of habitable space ship. Any way they would add weight to refueling tanker during lift off and further engineering design would be mandatory on both space ships.

  24. Mass to orbit reduction fully explained by the change to all sea level optimized engines – Assuming 1/2 of orbital velocity is provided by the BFS, fuel requirements go from 65% of mass (at 380s ISP) to 70% of mass (at 340s ISP). That extra 4-5% of starting mass has to be taken from payload capacity, since the lower stage isn't getting larger. Interesting trade off! Also means SpaceEx could increase payload mass to equal the 2nd generation SLS, just by changing the engines to space optimized ones, and eliminating the rear payload bay.

  25. Now we have 2 finned starship pretty much completed with separate landing gear not integrated with the fins and 3 sea level and 3 vacuum raptors. Wow

  26. And the BFR rocket is shrinking in numbers because on paper everything looks easy…but in reality it is very hard !
    When I heard the first time that the BFR will be 128 meters tall and 12 meters wide and will have 120 mega newtons of thrust out of 42 Raptor engines and 300 tons LEO payload capability … I couldn't stop laughing! And I do like Elon Mask and SpaceX and their plans and projects, but lets be real here….that thing will shrink more!

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