- Hi it's me, Tim Dodd,
the Everyday Astronaut. SpaceX's Falcon 9 rocket, the
world's first reusable rocket. (record scratching)
Wait! No it's not. Do you remember the Space Shuttle? It had those Solid Rocket
Boosters, and the Orbiter, which were both reusable weren't they? Well today we're going to talk about why the Space Shuttle failed
to actually be reusable and wound up being described with a more accurate word, refurbishable. People often cite the
shortcomings of the Space Shuttle and are quick to point it to SpaceX's claims of the
Falcon 9 booster being reusable. So today we're going to
look at what it takes to get the Space Shuttle
operational between flights, what it takes to get a Falcon
9 operational between flights, and why SpaceX's first stage booster take much less of a beating
than the Space Shuttle did. We'll also do a quick reminder of what technologies SpaceX
added to their Block 5 booster to hopefully achieve their goal of making a rapidly reusable rocket that can truly be reused 10 times before needing any kind
of serious refurbishment. Let's get started! - [Technician] Three, two, one, zero, and lift off. - [Neil] That's one small step for man. (upbeat, rhythmic music) - Reusable is definitely
the hottest buzz word in the new space industry. If you don't know why a
vehicle being reusable is such a massive game changer, may I suggest checking out my video Why does Falcon Heavy matter to help get a good perspective
on why reusability matters. But long story short, the margins to get stuff
to space are so thin it takes a massive rocket to put anything substantial up there. So unfortunately there's just
too little margins left over to add additional hardware
to make a rocket reusable. This makes spaceflight
extremely, extremely expensive. As in, so expensive we're
hoping to someday see costs come down to just
a $1000 per kilogram! Yeah, imagine those shipping
costs down here on Earth. Hi there, I'm calling to get a quote for some new tires for
my 2011 Hyundai Elantra. Yes of course it's the GT model. I did some really cool drifting and so that's why the tires are bad. How much would the new tires be? Oh $400? How much for shipping? $36000! And that would actually be a steal compared to the historically
astronomical prices of getting space hardware into space. Even the cheapest dollar to kilogram ratio is around the $3000 per kilogram mark, thanks to the Falcon 9 and Falcon Heavy. It's a good thing rocket
delivery isn't the standard here on Earth. So here's where reusability comes in. It's honestly fundamental. Of course! Why throw away super expensive
multi-million dollar engines and a massive fuselage
and all that extra stuff when you could just reuse it, right? I mean duh! Well that was the original
idea for the Space Shuttle. Believe it or not, NASA was seeking a reusable launch vehicle before we even put humans on the moon. The original studies began in 1968, some 10 months before Neil Armstrong famously took the first steps on the moon. As a matter of fact, one of the first people to fly
the Space Shuttle, John Young was walking on the moon when
he got news of the shuttle. - [Tony] This looks like a good time for some good news here. The House passed the space
budget yesterday, 277 to 60, which includes the votes for the shuttle. (beeping) - [Charlie] That's wonderful, wonderful. Tony, again I'll say it. With that salute I'm
proud to be an American. I'll tell you, what a
program and what a place and what an experience. - [John] Yeah, and I'll
say it too. (beeping) - [Tony] So am I. Country needs that shuttle mighty bad. - So with all the excitement
leading up to the shuttle, fast forward 50 years to today and the Space Shuttle has kind
of a bad taste in our mouths. It wound up being terribly
expensive, pretty dangerous, and actually more expensive than just about any other
way to get into space, although it could do things that no other launch vehicle could do. So with some of the greatest
minds working on the shuttle, why did it fail its promise
of bringing the cost down? Is SpaceX doomed to repeat history or has a lot changed in 50 years? So first, let's look at the
recovery methods of each system. They're quite different. The Space Shuttle utilized both parachutes and a lifting
body to recover hardware. Let's go in order of what was recovered, so starting with the Solid Rocket Boosters which were jettisoned around
two minutes into flight. The boosters separate while traveling around
4800 kilometers an hour or 3000 miles an hour, at an altitude of around
45 kilometers or 30 miles. And due to their velocity, they continue to coast
upward to their highest point of around 65 kilometers or 40 miles. Just a fun note, that does means the SRBs
never actually make it above the Karman line or the commonly agreed
upon boundary of space. So keep that in mind. The boosters fall back
through the atmosphere and start popping a sequence of parachutes at exactly 4786 meters or 15704 feet. Eventually after a pilot
chute, and a drogue chute, the three main parachutes deploy and splish splash the booster down relatively softly in the ocean. The Orbiter on the other hand
is traveling much, much faster and its recovery, like all
orbital things, is a lot hotter. About one hour before touchdown,
the Orbiter turns around and faces away from its
direction of travel or prograde. It fires up its orbital
maneuvering system or OMS and slows down 1%. Yep, that's it, only about 1%! And that's enough to lower its orbit from about 480 kilometers or 300 miles down to just 45 kilometers or
28 miles at its lowest point. That's crazy. The Orbiter then turns back around so it can reenter at
about a 40 degree angle. Now it's time for the
atmosphere to do its work. The Orbiter is absolutely
cruising at this point. It's still traveling around
27000 kilometers an hour or 17000 miles an hour, the Orbiter begins to hit air molecules and starts to build up a ton of friction and therefore a ton of heat. The Orbiter will reach temperatures of 1650 degrees Celsius or
3000 degrees Fahrenheit! Ouch! But luckily, the Orbiter is covered with four different types
of thermal protection. It has reinforced carbon-carbon
on the leading edges, then there were between
24177 and 31088 tiles, depending on the Orbiter, on the underside and front of the vehicle, then there is white Nomex blankets on the upper payload bay doors,
the upper wing and fuselage, and a few white surface tiles for low temperature areas as well. For 12 minutes, the shuttle
had so much hot ionized gases surrounding the vehicle, it
caused a full radio blackout. Eventually, after several
minutes of atmospheric drag and some computer guided S-turns, the shuttle bleeds off
a lot of its velocity. Once it's about 40 kilometers
or 25 miles downrange, the commander drops the
nose to minus 20 degrees, that's almost seven times steeper than a commercial airliner, and it's still traveling 20 times faster. Finally the shuttle lands
like a traditional jetliner, only a little quicker, touching down at 350 kilometers
an hour or 220 miles an hour on a 4.5 kilometer or
2.8 mile long runway. That runway's actually so long that there's over a one and a half meter or over 5 feet in
relative height difference between the ends of the runway due to the curve of the Earth! That's crazy.
(whistles) It's quite the journey! Welcome home, Space Shuttle. So now, let's do a quick rundown on how a Falcon 9 is recovered. I've covered this topic a
few times, more in depth, so if you have any questions remaining, check out my video How
SpaceX lands the Falcon 9. At around two minutes and
40 seconds into flight, the Falcon 9 shuts down its main engines, called MECO or main engine cut off. It coasts for a moment and then the first stage
lets go of the second stage for stage separation. At this point the Falcon 9 is traveling up to 8000 kilometers an hour
or almost 5000 miles an hour at an altitude of 65
kilometers or 40 miles. Quick note, that's about twice as fast as the Space Shuttle's rocket boosters. The first stage quickly
performs a flip maneuver with its nitrogen thrusters,
to point its engines prograde. Then, depending on the mission, the booster may ignite
three of its nine engines and do a boost back burn if
it's going to land back at land. But there might not be
enough margins left over to do the boost back burn. In that case it's omitted and the Falcon 9 continues on its ballistic trajectory away from the launch pad and
heads towards the drone ship that's been precisely placed
based on each mission profile. But in either case, the booster will coast
up to its highest point, typically over the Karman line or 100 kilometers or 62 miles. In other words, the booster gets to hang out
in space for a minute or so! Lucky, I wanna go. Around 55 kilometers or
34 miles in altitude, the Falcon 9 will light up
three of its nine Merlin engines as it reenters the atmosphere. It does this to slow itself down and it actually creates a
literal force field around itself so it can survive reentry. After around 20 seconds of reentry burn, the booster scrubs off 30
to 40% of its velocity, which is enough to
withstand the remaining heat as the atmosphere gets
thicker and thicker. The atmosphere will then take off another 60 to 70% of
the remaining velocity until the booster is only traveling about 1000 kilometers an
hour or 620 miles an hour. Then it lights up one or
three of its Merlin engines to perform the final landing burn which it needs to time perfectly. Even with just one of
the nine engines running at its minimum throttle, the booster still has
too much thrust to hover. So if the vehicle stops
before it hits the ground, it'll actually start going back up. Yeah, that's not good. This needs to be perfectly timed in a maneuver called the
hover-slam or suicide burn. Then the landing legs deploy and the Falcon 9 softly touches down. Well, hopefully. (explosive booming) So before we move on, let's
really quick remind you why the Falcon 9 doesn't use parachutes like the Space Shuttle SRBs did. Well there's a few reasons, and I'm just gonna breeze through these, since I've done many videos about this and I probably still need to do a more dedicated and
updated video about it. So here's Everyday
Astronaut's top seven reasons why SpaceX doesn't use
parachutes to land the Falcon 9! One: SpaceX tried to use parachutes on the first two Falcon 9
missions to recover the booster. Unfortunately, the booster is going about
twice as fast as the SRBs and the parachutes couldn't
survive the extra forces. Two: The rocket already has
engines capable of slowing down, why not use them? Does a helicopter need
a parachute to land? No it has an engine and
a propeller already! Three: You can't land a large rocket on Mars or the moon with a parachute, the atmosphere is too thin or nonexistent. So you'd better start practicing
propulsive landings now and get good at 'em! Four: The rocket needs to slow down before it hits the atmosphere
to survive reentry anyway. Remember that whole reentry burn thing? Yeah, a parachute can't work very well before it's in the atmosphere, so rocket engines are the only way to go. Five: Parachutes and the supporting system that would allow the fuselage to get stretched and not just compressed would just add otherwise dead weight. Six: Parachutes, although steerable, are not nearly as precise as grid fins, cold gas thrusters and an engine gimbal. SpaceX is finding this out the hard way as they tried to catch their fairings under steerable parafoils. Seven: Splashing down is bad mkay. Salt water and precise
liquid rocket engine don't mix very well. So that's actually a
great place to transition. Okay, so now that we recovered the reusable parts of the Space Shuttle and the first stage of the Falcon 9, what did they do to
prepare them for reflight? Let's start with the Space Shuttle. What did it take to get
one back to the launch pad? After splashdown, the
boosters were sealed up by scuba divers with a giant plug where they drained the water so it could be towed back
to Kennedy Space Center. Each booster required a crew
of 18 for ocean recovery. The Space Shuttle
obviously had two boosters, so that's 36 people on booster recovery. Then the boosters are disassembled and sent out to Promontory, Utah to be cleaned, paint stripped, repainted, inspected and reloaded
with solid propellant. Then they go back to Kennedy Space Center for assembly at the United
Space Alliance Assembly and Refurbishment Facility. I like the name of that place. The four segments in each booster are then mated to a new igniter, forward segment, nose cap, aft skirt and frustum, whatever that is. So basically just the casing
was actually truly reused. I definitely think refurbished
is the right word here considering they stripped it down to the bare metal each time and taken to a place called
the Refurbishment Facility. Okay, so the boosters aren't
at all what I'd call reusable, but how about the Orbiter? What's it take to actually
get that thing reflying? After touching down, a highly trained crew of 150 people and 25 specially designed vehicles head out to intercept the vehicle. They do safety checks for
explosives and toxic gases, helped the crew exit the Orbiter and eventually they tow it to the Orbiter Processing Facility. Once inside the 2700 square meter or 29000 square foot hangar, the shuttle would be processed
for approximately 125 days. More than 115 multi-level platforms would surround the vehicle so engineers could
check six million parts. Six million parts! What? But first technicians
would don hazmat suits to clean the vehicle of any remaining toxic
and hypergolic elements. Then they would remove the
Orbital Maneuvering System pods and the Forward Reaction
Control Systems modules to be repaired and retested. Then crews would take off all three of the Space Shuttle's
main engines, or RS-25's. These babies are still incredible engines, some of the most efficient
engines ever made. But they required a healthy
amount of inspection and refurbishment between each flight. Each engine had 50000 parts and about 7000 of which were life-limited and occasionally had to be replaced. In 2002, Kennedy Space Center took over assembly tasks of the engines instead of sending them
out for refurbishment. But perhaps the biggest and most daunting task
of the Space Shuttle was inspecting the thousands and thousands of fragile silica tiles on
the bottom of the Orbiter. There were between 24177 and 31088 tiles, depending on the Orbiter. Every single one was unique and had to be carefully inspected
and if damaged, replaced. And of course, all the
avionics, the payload bay, the hydraulic control
surfaces et cetera, et cetera, were carefully checked out
between each flight as well. In total, the Space Shuttle required no less than 650000 hours of
labor between each flight. Say the average person made $25 an hour, which I'm sure is kind of conservative for a highly trained technician, the cost of human labor to get a Space Shuttle ready for launch would be around 16 million dollars! And again, that's being
fairly conservative. But it wasn't always this way. Actually, before the
Challenger accident in 1986, the shuttle went through much
less refurbishment and checks. So few in fact, it may have seen as little as almost 1% the amount of
labor hours between flights. But after the Challenger accident, NASA changed the entire process of getting the Space Shuttle flight ready and wound up going over every single inch with a fine tooth comb. That's probably a good thing when you're dealing with human life. Oh and lastly, after 1989,
to get the shuttle ready it was placed on top of the
Orbiter Transfer System, a 76 wheel transporter,
to take it from the OPF to the Vehicle Assembly building to be mated with the external tank and the Solid Rocket Boosters. Fun fact, SpaceX now owns
the Orbiter Transfer System to transport their boosters! Okay, now time for the big question. What does it take to
get a Falcon 9 booster back to the launch pad? Let me start off by saying
a lot of this is speculation since SpaceX doesn't make public exactly what goes into preparation, but let's give a rundown
on what they have done, and what things they will be doing. So first off, if it
landed on the drone ship, a little robot actually comes out and grabs onto the
booster and hangs on to it so this doesn't happen. It's then transported back by a support crew of
around 10 and two ships. But if the booster lands on land, the booster is picked up by a crane and put onto their transporter. For the first few years
of the Falcon 9 reuse, the booster were shipped back to Hawthorne for the refurbishment. But SpaceX is building a
booster refurbishment facility at the cape. The first booster to ever land on December 21, 2015 for the OG2 mission, was extensively torn down and inspected. Since this was the first booster that SpaceX actually caught in one piece they had to check their work and see if it actually came out okay. On the first 13 reused boosters,
or non-Block 5 boosters, we know SpaceX changed out
the heat shields and blankets behind the exhaust nozzles. We know they had to fix
and repair the grid fins on the extra hot missions. We know they had to do a lot
of inspections on the vehicle but they also had to run
an X-ray along the booster to ensure the fuselage
is still good to go. Now I've heard speculations of between 1000 to 10000
human hours of labor for the turnaround of the
Block 3 and Block 4 boosters. And say this is terribly conservative. Say it's actually 100000 hours of labor, that'd still be over six times less labor than the Space Shuttle Orbiter. The Falcon 9 has much
less systems to check over than the Orbiter, so I think
it's pretty safe to assume there's a lot less labor hours required to prepare it for reflight. We know SpaceX has a goal with
their new Block 5 Falcon 9 to see it land and refly
within 24 to 48 hours with nothing but inspections
and checks between flights. The overall goal of
their new block 5 booster is to be reflown 10 times without any actual
refurbishment, only inspections. They built Block 5 having
learned the lessons from the 24 recoveries
leading up to Block 5. If you need a reminder of
what's new with Block 5, I have a video all about what Block 5 is and what has changed. A quick list of things that
are new with the Block 5 is a thermal protective
coating on the whole booster, a liquid cooled heat
shield by the engines, a bolted Octaweb, 8% increase
in thrust on the first stage, upgraded retractable landing
legs, titanium grid fins, an upgraded COPV 2.0 and a ton of tweaks that allow it to be even more reusable and most importantly,
rated for human flight. So how can the Falcon 9
booster actually be reflown without refurbishment? Can it? What's so different about the Falcon 9 compared to the Space Shuttle? Well let's first compare it to the SRBs and see what it actually does differently. First off, the SRBs
splashed down in salt water. That's not really a good thing. Solid Rocket Boosters are also basically giant empty canisters that are loaded up with a
rubber like solid propellant between each flight. This is different than a
liquid fueled rocket engine that has say tens of thousands of parts. If a liquid engine were to
be submerged in salt water, I don't think that'd be a good thing. So right there is probably
the biggest thing, having a booster land on
dry land or a dry ship deck, is a huge leg up as far as reusability
and refurbishment goes. As a matter of fact, the SRBs were so expensive to refurbish, in the long run, it was more
expensive to bring them back, tear them down and all that, than it was just to build new ones. So why is the Falcon 9 booster more reusable than the Orbiter? Well first off, the Orbiter
was not only a rocket, it was also a spaceship that
carried up to seven people. So a lot of work and check
outs went into the cockpit, the interior, the payload
bay et cetera, et cetera, let alone the actual rocket
engine portion of the Orbiter. The RS-25 engine, although amazing and eventually refurbished on-site, still required an awful
lot of work to fly again. The Merlin 1D engine
that SpaceX has developed has been fired over 5600 times, and is designed to be reflown
and reused over and over with minimal inspections. How much, we don't really know yet, but more on that in a second. But perhaps the biggest difference between the Falcon 9 booster
and the Space Shuttle Orbiter is the velocity in
which each one reenters. Let's compare the velocities of the SRB, the Falcon 9 first stage and the Orbiter to help understand why each one uses their
given reentry system. The SRB never exceeds
4800 kilometers an hour and it also stays lower in the atmosphere so it doesn't require
any kind of slow down before it reenters, well because it never really
exited in the first place. The Falcon 9 on the other hand goes from up to about
8000 kilometers an hour down to as low as about
5000 kilometers an hour in order to survive reentry
using its retropropulsion. But it's safe to say it
will probably never see much more than 8000 kilometers an hour. The Orbiter reenters at speeds of up to
27000 kilometers an hour but it slowly bleeds
off a lot of its speed in the upper atmosphere. Wow. Those are some pretty big
differences in velocity. Since the Falcon 9 booster reenters at only 8000 kilometers an hour it experiences up to
almost 40 times less heat compared to the Orbiter. What? How can that be? Well, since the first
stage of the Falcon 9 only gets up to at most about
a third of orbital velocity, it receives much less than just
1/3rd of the amount of heat. The compressed gas on the
leading edge of any vehicle will see heat increase by velocity squared but the thermal energy
transferred to the rocket goes as velocity cubed! So that means if a vehicle is
traveling four times faster, the bow wave in front
can get 64 times hotter! 'Cause that's four times
faster, times four, so squared, times another four, cubed, so 64! Now this is an oversimplification but that's why the Space Shuttle needed those carbon-carbon leading edges and those silica tiles
all over the bottom of it to survive reentry. Not only that, but the Falcon 9 also does an a pretty
significant retropropulsion burn before it reenters, to ensure
the vehicle can survive. The Space Shuttle didn't do any of this because it relied on
its large surface area to slowly bleed the speed
off for several minutes. As a matter of fact, the Space Shuttle spent almost
10 times the amount of time radiating heat off through reentry, which is the key to how its
non-ablative heat shield worked. So long story short. The first stage is going slow
enough to not get crazy hot, so it doesn't require nearly
as much thermal protection. Therefore it's probably safe to say it doesn't require as much
refurbishment, hopefully. (upbeat, melodic music) So some final thoughts on all this. First off, the reason
why I think the Falcon 9 will actually achieve reusability when the Space Shuttle couldn't is mostly due to the engineering
philosophy of SpaceX. They are constantly tweaking their rocket, to the point where according to SpaceX's VP of
production, Andy Lambert, SpaceX has "Never built any
two vehicles identically, "such is the pace of
innovation at SpaceX." Now this is quite different
from the Space Shuttle that had only only five
operational vehicles that changed very little in
their 30 years of operation. As a matter of fact, phase
one of the Space Shuttle was only the first four
flights of Columbia. After that, further
development would be minimal. But with the Falcon 9, if
an idea doesn't work out, they can literally make that change on one of the next manufactured boosters. And if it's a really big change, they'll do that on the
next block iteration. The Space Shuttle's design
didn't exactly freeze, but it certainly didn't evolve
nearly as much in 30 years as the Falcon 9 has in eight years. Some might consider this
much change reckless, but considering the end goal is to actually have a reusable vehicle, I'm really glad they're
pushing this aggressively. I just can't wait another 30 years. And lastly to those that think SpaceX won't be able to make it
worth the cost of reflying, or who question whether or not
it'll be worth it for them, luckily for us, it really doesn't matter. SpaceX is a private company. They will only do what makes
the most financial sense. So if after a few years
they look back and realize it's more expensive to
try to refly these things than it is to make a new one, I'm sure they'll stop doing so, because they don't wanna lose money. They don't owe it to anyone
to reuse their rockets. It's only in their best interest to figure out how to do so
so they can maximize profits. And that's just different
than the Space Shuttle which had the weight of the
entire nation's expectations to be reusable. Whether or not the system put
in place actually made sense, it was too late. There was no room for
major changes per say since Congress would probably frown upon, "Well this didn't work out,
let's scrap the entire idea." So personally, I think with this new age
of innovation and materials, rapid evolution of hardware and software, and leadership that simply
requires they keep trying until they figure it out, I think we're finally entering a new era of reusable and airliner like rockets. Hopefully! So what are your thoughts? Is actual reusability finally upon us or do you think we're
still going to be stuck in refurbishment land? What other questions do you have? Let me know your thoughts,
questions, and video requests in the comments below! Thanks to Lukas from kNews
for his amazing animations. I've always been a fan of his work and was so happy to work with
him on some of these visuals. Be sure and check out his awesome channel where he does updates on spaceflight news and other great
spaceflight topics as well. Check it out, kNews! And of course I owe a huge
thanks to my Patreon supporters for helping me make this and all other Everyday
Astronaut content possible. You guys are seriously amazing! And you help me stay sane during all these long bouts of research. They hang out in my exclusive discord and our exclusive subreddit, to help me script and research. If you wanna help contribute, please visit patreon dot
com slash everydayastronaut. Thank you, seriously thank you. As always, all the music
in my videos is original. Feel free to check it out for free at soundcloud dot com
slash everydayastronaut. Tell a friend. Hey guess what? This ridiculous shirt is finally
available in my web store, along with a lot of other
fun things like hats, mugs, prints of rocket launches
or original other work and lots of other fun stuff at everydayastronaut dot com slash shop. Have fun. Thanks everybody, that does it for me. I'm Tim Dodd, the Everyday Astronaut, bringing space down to
Earth for everyday people.
The shuttle had three reusable components: the orbiter, the space shuttle main engines (SSME), and the Solid Rocket Boosters (SRB).
Upon landing the orbiter was essentially decertified for flight. The recertification process required 250,000 to 500,000 work hours. About 80,000 of these hours were required to refurbish the thermal protection system (TPS).
The SSME was supposed to be certified for 25 flights without overhaul. Actually, that engine was certified for 20 flights at 104% rated thrust and 8 flights at the 109% level after exhaustive ground testing that ran until April 1984. Through the first 100 shuttle missions, one engine achieved 22 flights, two engines reached 19 flights and 2 reached 17 flights. A total of 43 engines were flown on these missions and the average was 7 flights per engine. Each SSME cost about $50M in today's money.
The SRBs were parachuted to the water, towed to port at Cape Canaveral, completely disassembled there, loaded onto railroad flatcars, and shipped to the Thiokol plant in Utah. There the SRM was essentially remanufactured. There were 68 refurbishable parts, most of which were expected to have a 20-mission lifetime. NASA's plan was for to have each refurbishable part fly on every fourth mission. Only six of these refurbishable parts were associated with Thiokol's Solid Rocket Motor (SRM), but these were the massive SRM segments that accounted for 99% of the weight of the SRB. Most of the refurbishable items were part of the Solid Rocket Booster (SRB) and were processed by United Space Boosters, Inc. (USBI) which had the SRB assembly contract.
The SRB manufacturing cost was about $50M in today's money and the cost of refurbishment was about the same. Cost savings from SRB reuse was essentially zero. However, after the Challenger disaster (the 25th shuttle mission) NASA had no choice but to continue to fish the SRBs from the ocean, disassemble the SRM, and examine each of the O-rings to ensure that the redesigned joints continued to operate properly.
Another good video Tim. I understand the comments regarding pitch but please don't change anything. Your videos are great for school and inspiring young people that science is important and relevant!
I like your content, and I don't think youll change anything because you are clearly doing well. But I always feel as if you treat your audience like children. Like you are talking to children. If that makes sense.
Scott Manley feels like an adult talking to adults. Which makes the videos more enjoyable since they feel like I'm the intended audience.
But regardless, the content is high quality. Maybe it's just me with feeling like the presentation is patronizing..
No disrespect meant. Just an honest opinion.
Makes me wonder what the BFS will take, The BFS will be the SpaceX Shuttle essentially. I mean they will have to achieve the goal, Since even if E2E does not pan out. Where the BFS is intended to go does not have a full shop so it will have to be able to relight and do a full interplanetary mission without major work.
Of course while the shuttle did not meet its goals and certainly showed how cost plus can cause problems I will say it is still probably one of the most fantastic achievements in history from a technical angle.
Great stuff.
I think it would be great if you did a short form vid focusing only the on the economics. Something like:
Then briefly give an example of spreading the fix cost + incremental costs over the lifetime (say 10 flights).
why didnt you take the Dragon into account in your explanation ? It has the same issues at reentry as the orbiter, and it will be able to transport humans. That would make the comparison more complete. Even if it's only Dragon 1 used for CRS...
Great video. I do wonder why the RS-25 engines have to be torn down more than the Merlin 1D engines per flight. I would have thought that burning H2 would be cleaner and thus require less thorough inspection than Kerosene which can leave deposits in odd places. Or is it burn time? Or is this just a case of NASA hyper-paranoia? Or something else?
Love your videos, Tim! I think you cover great discussions and debates while laying out the arguments of all sides in a way that any audience member could follow. It's always great to see this kind of connection between science and the public. I have a few nitpicks, though!
@5:30 I think you could have been more clear that prograde is the direction of travel and not the direction the shuttle faces after turning around. I had to listen to it a few times to realize it wasn't a mistake!
@6:15 you say the orbiter "starts to build up a ton of friction and therefore a ton of heat." I think this is actually a very interesting topic you could do a short video on, but that's actually a common misconception! Nearly all of the heat generated upon reentry of any manned vehicle (more
specificallygenerally, of any blunt body) comes from the compression of air in front of the craft. The craft itself is protected by a boundary layer of air that helps keep most of that heat away from the body. So while technically what heat does enter the vehicle does so through friction (or rather convective heat transfer), it's actually compression that generates the heat along the shockwave while pressure slows the vehicle. Friction has nothing to do with it!Edit:
Are those little vehicle animations your making? They look great!Nevermind, I should have finished the whole video first! Lucas does indeed have awesome animations!Great video, as always Tim! Keep it up.