SpaceX Starship Refilling Plan Change? Catching Arms Coming Soon, Cygnus NG-16 Mission
This video is sponsored by Brilliant. Hey, Hey Marcus House with you here, and after the previous few breakneck weeks in Boca Chica, things seem to be just a little calmer this week and we get to finally dive a little deeper on everything going on at Starbase. A great deal of important work has been going on and several things have to happen before SpaceX can start the fiery testing campaign of Booster 4 and Ship 20. We will discuss orbital propellant transfer and the most recent numbers regarding the Raptor design. Then of course we had the
successful launch of Cygnus-16 carrying supplies for the International Space Station! Ok, so recently it’s been pretty crazy right? We went from having a bunch of sections for Booster 4 and Ship 20 scattered around the production site, and within two weeks we were watching scenes like this! The full Starship stack was presented there right before our eyes for the first time. This did make waves around the world too. A bunch of news networks did actually pick up the story and run it. What made this particularly special I think was the terrific scenes such as this by Elon Musk. That image there intended to take you back to the history made in the past with equally impressive technological feats of brilliance at the time. Including the launch stand, the full Starship and booster stack towers over 140 meters off the ground, with the rocket alone making up around 120 meters of that. Now repeatedly this week, I was told in the comments that it doesn’t look as big as expected, but as always, it is hard to fathom scale from a distance. We see this
quite simply with this terrific shot by the incredible RGV Aerial Photography. At a distance, yea...It just looks like a rocket. It’s only when you see those humans for scale, or the size of the monstrous cranes that it really becomes apparent. If you stuck it next to the Statue of Liberty which is around 93 meters tall, well yea… you get the idea. It’s big. It is also easy to forget just how fast all this has come together. Yes of
course we see those regular taunts telling us how far things are behind from Elons planned schedule. Sure. I think that is always going to be a thing, but just take a few moments to compare the launch site 12 months ago. Just a little over a year ago on August 5th, we witnessed the flight of the SN5 prototype. Here we see it after its landing at the launch site. It truly is amazing to see what kind of progress can be made when a profound and
clear goal is put ahead. As Elon often quotes in interviews and on Twitter, “Rapidly Reusable Rockets” are the key to making humanity a multi-planet species. Without those three R’s, we’ll never be able to lower the cost needed for exploring the solar system efficiently. It's absolutely clear that being Fully and Rapidly Reusable is the goal for SpaceX, and the progress seen over the past year is a true testament to how badly they want it. If this isn’t something that gets you excited about the future, then I don’t
know what does. Of course, this isn’t guaranteed. SpaceX has finite resources and this challenge is one never achieved before. There are still a lot of IF’s here. That is why the space community cheers them on every chance we get. We cover this every weekend and need your help to spread this story to those that are unaware of what is happening. Thanks for helping us do that. While SpaceX is innovating at this rapid pace, we expect to be continuously
amazed over the next decade. On top of that, it’ll be a treat to see the other launch providers walk the path that SpaceX is paving. Not unlike the massive push for electric vehicles following in the wake of disruption lead by Tesla. It really is astonishing to watch it all unfold and the real party starts once the full rocket has cleared the tower and successfully heads for orbit. So last week we left you with SN20 having been rolled back to the launch site after being unstacked. What has happened this week?
Thanks to the continuous and amazing work capturing the goingson by BocaChicaGal and NASASpaceFlight, we can see that it is quite a lot. Not the mad amount of stacking we’ve seen the last few weeks, but exciting stuff all the same. The engines on Ship 20 were removed to allow for access to get the ship into a flight-ready configuration. Not long after the stacking milestone, Musk himself sketched out a few of the tasks still in front of the rocket. Namely, he says that SpaceX must still complete a number of things which will only take another week or two. Ship 20’s partially-finished heat shield needed more work with it being around 98% done. Seems like that should be finished now right!? Well
not necessarily. The tiles that were remaining after Ship 20 was stacked are the tricky ones that require some custom shapes. Although most tiles come in a small number of variations, dynamic machining is still required for some areas. Early in the week, we could clearly see workers marking the tiles with these stickers which looks like an inspection process indicating where a tile may need to be replaced or tested. Starship gazer here picking up incredible detail of all that. Quite a number of these are cracked. Not sure if this was just due
to rapid installation issues or something else there. The ship was rolled out into the open and after inspection, they began removing a lot of those prior to replacement. On Friday it was rolled back to the launch site, so we are hoping to see some further testing on this beast very soon. Secondly, SpaceX needs to install some form
of shield to protect Booster 4’s 29 Raptor engines. You’ve only got to look at this image to see why, if all this plumbing is not covered, it might suffer hard on re-entry. I’ve always imagined something like what we see on Falcon 9 here. All the plumbing is covered over leaving really just the engine bells exposed with the appropriate space to gimbal the engines. They need to finish installing, plumbing and activating the massive ground
support propellant storage tanks, too. And let’s not forget about the construction and installation of the umbilical arm on the launch tower to fuel and power Starship. Elon re-confirmed on Friday that the Starships will still be being caught by Mechazilla as well as the booster. Due to that no need to legs until they go for moon or mars landings. Beautiful new animation here by TijnM_3DAnimations. Check out their feeds if you arn’t following. It should all work very closely to this and Mechazilla will have arms very soon! On Tuesday the 10th of August SpaceX removed Booster 4 off the launch ring and on Wednesday off it rolled along highway 4 back to the construction site to prepare for testing.
I’m sure it will be facing an even more ambitious pressure and static fire test campaign than we’ve seen in the past. Before we knew it the removal of engines followed. The next steps would be to perform testing of the central thrust plate, then pressure tests and a static fire would follow. After that the big tests with SpaceX moving onward to a full 29-Raptor static fire on the orbital pad. Speaking of Raptors a new hydraulic ram system to test out the thrust plate for future boosters has been spotted this week. This of course simulates the forces that the plate will experience with the roaring raptors firing underneath. The rams push upward with that same force to test that it all holds. I’m not sure
if this is an updated design to the previous ram structure or not. What is better than checking out the hydraulic rams for the inner set of engines!? Well, I’m glad you asked there, curious Starship watchers because this here is the same sort of system to test the outer engines as well. All 20 of them! That is the first time we’ve seen a device for testing the outer set, so we can only assume that booster 4 is destined to be stress-tested in the coming few weeks. I suspect this mystery structure here may be combined with the ram systems for booster tests, buuuut, I really have no evidence to back that up. That is
pure speculation right now. What do you think? Let me know in the comments. I suspect we will see a fairly lengthy testing campaign for both Booster 4 and Ship 20. Let’s face it, we really do not want to see a full stack exploding on the pad. If it can at least make
it off the pad and a few kilometers up and out over the ocean, that would be a great start. There would be a fair amount of paranoia around this first launch I imagine. Behind booster 4 of course is booster 5 and we’ve seen various sections of this now including the new common dome sleeve and forward tank number 2. A sneaky screengrab from Elon strolling past this section here in Tim’s Part 2 interview with Elon Musk also tells us that this is for Ship 21 which should go with Booster 5. The Aft dome is riiighht there,
so before we know it we’ll be seeing the stacking of the next ship and booster. Ok, so let’s talk about the refilling method that came to light from that same interview. Previously of course the idea was that a tanker and ship would dock together from rear ports. In the interview here Elon said that he is “Not Sure” that it will be this method anymore. Instead, it might be something different. Now, this could mean that we will see something
like this as rendered here by ErcX, although saying that, Elon did reply that this looks hot! Not sure of course if that was confirmation or sarcasm. The reason behind the community going a little wild with speculation here is because Elon mentioned in the interview that SpaceX had moved the fill drain lines to the side instead of underneath. The systems involved with setting up such a filling process were adding mass to the booster. Why do that if you can use ground support equipment and lighten the dry mass? It is the same reason that SpaceX has chosen to remove the legs and catch it right out of the air. The problem with refilling in zero gravity of course is that the liquids are all just floating around. There is no force of gravity pushing the fuels in any direction. So if
they are connected like this, what you first need is for the liquid oxygen and liquid methane to settle into the bottom of the tanks in both ships. For that, Starship can use very small amounts of reaction control to push up from the bottom. That only needs to be a tiny acceleration. We see SpaceX do this with the second stage of the Falcon 9 before a relight. Not a problem with short durations, but even a tiny acceleration of even a few
centimeters per second squared might mess up the orbit quite a bit when provided over ten minutes or so. Keep in mind that we’re talking about roughly 150 tons of propellant being transferred so that will take time. Could it be that they do not push forward but try to roll? Then how would you actually get the fuels to come over? Well, as many are suggesting, you just put pumps in. However, I speculate that instead, you could manipulate the gas pressures in both tanks. If you can increase pressure in the tanker, and lower
pressure in the ship, the fuel would simply be sucked through. No need for pumps then. Just a pressure difference of a tenth of a bar would press with a ton per square meter onto the propellant. The ships need all the systems for autogenous pressurization and recondensing anyway, so this could be fairly straightforward. I’m not an expert in such things so would love to know what you think. We got some more insights regarding the Raptor engine as well. In part 2 of Tim’s interview, Elon said that the Raptor Vacuum engine, or RVac for short, has an expansion ratio of around 80 to 1 which is to be improved to around 90 to 1. In this example, the expansion ratio essentially means that the area at the
end of the vacuum engine bell is 80 times the area of the throat at the thinnest part of the engine. The larger you can make that ratio the better for the specific impulse. We assume this applies to the RVac Version 2 as the numbers don’t add up to us otherwise. As Aeneas calculated here, with such an expansion ratio, the engine bell might be smaller than 2.3 meters and the efficiency unrealistically high. 2.3 meters is the estimate that the 3D artists use for the current size. Interestingly, nearly a year ago, Elon said that the expansion ratio is 107 to 1 while talking about the current RVac. That actually makes more sense.
There are practical limits on how big you can make the engine bell and how small you can make the throat though. You can see how big the three are there on Ship 20. And that is a 9 meter wide vehicle of course. But the problem here isn’t just the width of the nozzle. You can only increase the expansion ratio in a reasonable manner when also adding length to it. In case of Starship, this is the limiting factor. To allow more relative length, you’d need to reduce the overall size of the engine. So yes, we are curious how they want to solve this when using the same chambers and pumps for all engines which will increase the thrust. It doesn’t help that just weeks before, Elon said, that the
vacuum engine is currently expected to achieve a specific impulse, or Isp, of 378 seconds. This may then go up beyond 380. To us, this seems impossible with an expansion ratio of 90. So yes, there are many open questions. But Raptor Version 2 is coming to the test stand in a month or so and will be more compact and streamlined. Elon mentioned that all the pipes and cables of the current version look like a Christmas tree compared to Raptor 2, so I can’t wait to see how different that looks, and maybe more details will be provided then. SpaceX are also working on a much simpler nose cone design as well which is much neater and more simplified than previous versions. You can see from the current style, 3 separate
rows containing the rectangular panels individually pressed to shape and welded. This is the new one, which will be made from two rows with the sheets being stretch formed. Probably not too dissimilar I guess to this kind of process that we see here. We should start seeing new prototypes using this style appearing soon. There is a lot more information in Tim’s
videos all linked in the description. Check them out if you haven’t seen them yet. The ground support equipment or GSE tank development has continued strongly. Early in the week GSE tank 7 was mostly stacked in the mid-bay, and just needs its aft dome at this point I think. The cryo shells continued stacking as well. This cryo shell here was lifted and placed over the GSE-3 liquid oxygen tank. One here rolled to the launch site early in the week and as luck would have it, Jack captured this interesting label proving that this one, in particular, is shell 4, which is for one of the two liquid oxygen tanks. GSE Tank 6
rolled down to the launch site mid week to be placed into the tank farm at the same time as booster 4 was rolling in the opposite direction. The GSE tank actually needed to make way there. No time for separate road closures. On Friday that was lifted into the tank farm. For those that haven’t been following these very closely those shells are placed over the top of the main tanks underneath to insulate them. Brendan Lewis has been keeping us up
to date with all the changes which you can see from his most recent diagram here. Now you will notice the new GSE area in the bottom corner that lets us know how things are going with that birds-eye perspective. The tanks show the contents as far as we know them. As we can see here the oxygen and methane are separated by the water and nitrogen tanks which helps limit some explosive potential in case of a disaster. This is all very handy for quick reference so follow Brendan on Twitter or Patreon there to access these diagrams as soon as they are released. He does a fantastic job keeping everything updated. We had some launch action this week with Northrop Grumman’s Antares rocket roaring off the pad on August 10th with Cygnus 16... [SPONSOR AD START]…we’ll talk about that in just a moment, but first, a thank you to Brilliant for being this video’s sponsor.
As our videos dive deeper into areas that we are a little less familiar with, I often need to expand my areas of learning and research. With the good habits learned with Brilliant’s interactive learning structure, we’ve been able to provide insight into the math and science to hopefully allow us to better explain the topics we cover every week. You can start off with a fairly basic idea such as this lesson on the center of mass. This is all part of Brilliant's newly-updated Scientific Thinking course, packed with interactive exercises just like this that let you visualize these ideas quickly and intuitively. Shifting the
balance point here lets you immediately see how the mobile balances out. Well, guess what!? The center of mass in rocketry is a similar idea. Just more advanced. Evolve your way up through Classical Mechanics which outlines the key ideas behind all things rockets. Learn the fundamentals to start an incredible journey understanding chemical relations between propellants or the way the Rocket Equation works. That is just one example of the rabbit hole of topics you may find that triggers your interest. On top of that, you get to expand your level of learning through daily challenges and visual concepts that help strengthen your knowledge.
If you would like to give it a try head to brilliant.org/MarcusHouse. The first 200 people will get 20% off the first year of Brilliant Premium. The link is in the description. [SPONSOR AD END] So yes, we finally got to see some launch activity with the Cygnus 16 mission. [pause] This launch took place on Tuesday from NASA's Wallops flight facility. NG-16 which is their 16th commercial resupply mission had its liftoff was delayed slightly due to a helium leak, but that was quickly addressed, allowing the countdown to quickly resume. The launch window opportunity was running out fast so the ground crews did an amazing job here to keep things on track.
Roaring away from the pad with the two Russian-made RD-181 engines, the launch itself was a beautiful sight. Just listen to that roar! [rocket sound] The sound of these launches is always quite astounding I think. Northrop Grumman’s Antares 230 series rocket here safely carried its payload to Low earth orbit where it commenced chasing down the International Space Station. As is tradition, this flight's Cygnus cargo vessel was named in honor of Elison Onizuka.
With a 2-day journey completed, the capture of Cygnus was achieved using the Canadarm 2, controlled by Megan McArthur and Thomas Pesquet. It was berthed to the Unity module by flight controllers in Houston where it will remain until November. It will then detach and head back for a destructive reentry along with a heap of waste from the aging space outpost. So yes, with just over 3,700 kilograms or 8,200 pounds of research, crew supplies, and Hardware this represented the largest resupply load to date. The crew of course will always welcome some special treats such as assorted cheese, pizza kits, apples, tomatoes, and kiwi fruit. Good food is always a great morale booster. Also onboard is another mounting
bracket assembly for the next set of roll-out solar arrays that will augment the power supply for the ISS. There are some pretty cool science experiments onboard such as the Redwire regolith 3D printer which could possibly evolve to one day build structures at lunar or Mars bases. Also experiments that due to having a perishable nature, are very well suited to the pop-top fairing unique to the Antares launch vehicle. I have included a link below if you would like to check out some of the other experiments including KREPE, CO2 Scrubber, and BLOB. So yes, it was nice to see that launch occur after quite a slow week with space launch activity. That has you up to date for yet
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