[00:02] down to map out the Starship HLS, the groundbreaking lunar lander at the heart of the Aremis missions, the hardest part of the job isn't what you'd expect. It's not about keeping the astronauts alive in the vacuum of space. Between the
[00:16] lessons learned from the Dragon capsule, the decades of experience on the ISS, and the treasure trove of classified data from the original Apollo missions, both agencies have a solid handle on life support. No, the real nightmare for
[00:31] the design team is something far more downto- earthth landing legs in the entire sequence of a lunar mission touching down the HLS is the moment of truth. We have never seen a vehicle this bold or this terrifyingly large attempt,
[00:45] a landing on another world. Standing at 50 m tall, roughly the height of a 15-story building landing starship on the moon, is less like a traditional balance a pencil on a pile of loose sand. Even the Apollo data doesn't help
[01:01] much here. The original lunar module was a stout 7 m tall spider with a low center of gravity that allowed for a relatively gentle landing. Starship, by contrast, is a towering monolith. And then there's the sheer weight of the
[01:15] challenge, we have to look back at the early days of the Falcon 9. If you early days of the Falcon 9. If you followed SpaceX between 2013 and 2015, you remember the footage. You saw the Falcon 9 falling from the edge of space,
[01:28] its engine screaming like an inverted torch, trying to bleed off hundreds of torch, trying to bleed off hundreds of meters/s of velocity to hit zero at the exact moment of impact. And then boom, explosion, another explosion, and
[01:41] another. We watched drone ships in the Atlantic blown to splinters. We saw boosters tip over and roll into the ocean like felled trees. Spac X didn't hide it. They put it all on display. It wasn't until December 2015 that the
[01:56] Falcon 9 full thrust finally stuck the landing. But here's the kicker. The dry mass of a Falcon 9 booster is only about 22 tons. Even with leftover landing
[02:08] fuel, you're looking at maybe 25 tons hitting the deck. Its four landing legs only had to support about 6 tons of force each landing on a reinforced flat force each landing on a reinforced flat rock solid surface. But Starship HLS, it
[02:22] doesn't get the luxury of a flat landing pad. It has to settle onto the rugged, uneven lunar regalith, a surface so treacherous that even astronauts on foot have been known to stumble and fall. If it took that many rapid unscheduled
[02:36] disassemblies to master a 25-tonon booster on Earth, how many times will they have to blow up the HLS before the landing gear is optimized for the moon? Because unlike the Falcon 9, Starship HLS isn't an empty shell when it lands.
[02:51] It's carrying its entire whole life support systems, a full crew scientific cargo, and most importantly, the massive amount of fuel required to blast back off into lunar orbit. We are talking about a landing mass somewhere between
[03:05] 200 and 300 tons depending on the final mission configuration. Now you might think well the moon only has 16th of Earth's gravity so it'll be easy right? That is a dangerous misconception. Low gravity does not mean the physics of
[03:19] gravity does not mean the physics of impact suddenly become a breeze. A 250 ton object on the moon still has the inertia of 250 tons. If that descent velocity isn't controlled to perfection, the kinetic energy of the impact will
[03:33] shred those landing legs like toothpicks. So, how exactly has SpaceX designed the landing legs for the Starship HLS to tackle all of these monumental challenges? Did they just copy paste the landing legs from the
[03:46] Falcon 9? Absolutely not. They had to go back to the drawing board and the result is a landing system unlike anything in the history of aerospace engineering. Let's start with the raw numbers. Under the moon's 16th gravity, the static
[04:00] force pushing down on the surface is roughly 35 to 50 tons. Split that between four legs, and each one has to support a static load of 8 to 12 tons. But that's just while standing still. At the moment of touchdown, the peak impact
[04:15] force could double or even triple in a heartbeat, depending on the descent velocity and the density of the regalith underneath. That is why SpaceX ditched the toothpick legs of the Falcon 9. In the 3D concepts they've released, the
[04:29] legs are short, stout, and undeniably metallic with feet wide enough to prevent the ship from sinking into the lunar dust. The stride of the HLS needs to be unusually wide compared to the ship's diameter, spreading across 15 m
[04:44] or more. This creates a massive stable footprint that keeps the center of gravity safely within the contact points even if the ground is tilted by several degrees. Materials are the next chapter of the story. The HLS hole is built from
[04:59] reinforced stainless steel with extended fuel tanks painted brilliant white to reflect the harsh solar radiation. Stainless steel, specifically the 300 series Spac X favors, has a melting point above 1,400 degrees C and can
[05:14] withstand extreme thermal shock without warping. This choice is no accident. When those vacuum- rated Raptor engines blast superheated exhaust onto the lunar surface at close range, the temperatures can exceed the limits of the carbon
[05:27] fiber composits used on the Falcon 9 legs. Carbon fiber burns, steel does not. But now, let's talk about the challenge most people overlook. How does this massive ship actually see where it's going when its own engines are
[05:41] kicking up a blinding curtain of dust? SpaceX has been rigorously testing landing software sensors and radar to ensure the hardware can pinpoint its landing site with surgical precision. This system known as terrain relative
[05:55] navigation, TRN, is essentially a threelayer consciousness that kicks in as the ship approaches. At tens of kilome up, the system compares live surface images with highresolution lunar maps, much like a
[06:10] pilot recognizing city streets from an airplane. At mid-range, 3D lidar begins scanning the terrain in detail, hunting for the flattest rock-free patch within maneuvering range. But in the final stretch below 100 meters, things get
[06:24] incredibly difficult. At this altitude, the HLS is expected to switch to smaller landing thrusters located midway up the hole. These thrusters burn gaseous oxygen and methane rather than liquid to soften the blow to the lunar surface.
[06:39] This is the secret sauce. If the primary raptors were used all the way to the ground, they would sand blast the regalith into a high velocity storm of rock and dust, completely blinding the optical sensors and lidar. By switching
[06:54] to smaller engines mounted higher up, SpaceX creates a clear window for the navigation system during the most critical seconds before the boots hit the gray dust. But beyond the puzzle of the landing legs, there is another
[07:07] challenge that rarely gets a mention. one that hides deep inside the gut of the ship. It is silent and invisible, yet it has the power to sabotage the entire landing in its final seconds. Take another look at the architecture of
[07:21] the Starship HLS. But this time, look at it vertically. About 2/3 of the lower vehicle, the massive steel body stretching tens of meters high is dedicated to fuel tanks. These carry hundreds of tons of super chilled liquid
[07:35] oxygen, LO X, and liquid methane, the lifeblood that propels the ship from Earth's orbit all the way to the moon. Only the top 1/3 houses the crew cabin life support elevators and the scientific gear humans need to survive.
[07:48] What does this mean for the landing? By the time the HLS prepares to touch the used for the journey has been scorched away. The tanks are now mostly empty, save for about 100 tons reserved for the later ascent stage. The bottom section,
[08:03] which once accounted for the vast majority of the ship's mass, is now largely hollow. The center of gravity has shifted significantly higher than what is ideal, and physics is unforgiving to those who challenge it.
[08:15] But the story gets even more complicated. When a fuel tank isn't completely empty, when a small amount of cryogenic liquid is still slloshing around at the bottom, a dangerous physical phenomenon takes hold.
[08:27] Propellant slosh. To understand why this is so perilous, imagine a water bottle that is only 1/3 full. When you tilt or shake it, the water inside slams back and forth. The force of that liquid hitting the walls creates a moment of
[08:41] force that can jerk the bottle in a direction you didn't intend. In Starship, this slloshing fuel transfers torque to the hole, creating oscillations that cause the spacecraft to wobble a phenomenon known as
[08:54] mutation. If left unchecked, nutation can grow exponentially. For a 50 m rocket in its final landing phase that spells disaster, aerospace history is littered with expensive lessons on this subject. In 2007, SpaceX's second Falcon
[09:09] one flight lost control 5 minutes in because of propellant slush after the first stage separation. The second stage tank lacked anti-slash baffles, and the pre-flight simulations hadn't accounted for the impact of the stage separation.
[09:25] Millions of dollars worth of rocket plunged into the Pacific because of a pool of liquid that no one controlled. So, how does SpaceX solve this? The answer isn't a single piece of hardware. It's a systematic approach across three
[09:38] parallel layers. The first layer is passive physics baffles. This is the oldest trick in the rocketry handbook, and it's still irreplaceable. Baffles are structural partitions attached to the tank walls that act like small dams,
[09:52] increasing hydraulic drag and dampening the waves of the liquid inside. Even Apollo learned this the hard way. The lunar modules of Apollo 11 and 12 experienced fuel slush that caused fuel sensors to report empty 30 to 45 seconds
[10:08] earlier than reality. It wasn't until Apollo 14 that NASA installed fixed oscillations. Starship HLS uses similar baffles refined specifically for the lunar profile. The second layer is active
[10:24] control engine gimbals and thrust vector control TVC. This is where the software becomes the unsung hero. Controlling a rocket with slloshing fuel is modeled by treating the liquid as a multi-deree of freedom
[10:38] pendulum system. The flight computer must simultaneously manage velocity attitude and suppress those oscillation modes all through a single adjustment, the tilt angle of the engines. The HLS flight computer has to feel the
[10:53] oscillation frequency of the remaining fuel in real time and adjust the thrust vector so it never excites the natural frequency of the liquid. In lunar landing simulations, slosh effects begin to build around the 200 second mark and
[11:06] can last until 500 seconds. A single hiccup in thrust could send that sequence spiraling out of control. This is exactly why SpaceX has been running grueling throttle tests on the Raptor
[11:19] engines to mimic the exact thrust profiles they will use on the moon. The third and most subtle layer is sequential propellant management. Instead of draining all sections equally, the HLS fuel system is designed
[11:31] to burn propellant in a specific order. By controlling the burn rate of the LO X and methane, they can keep the center of gravity of the remaining liquid in the most favorable position for stability. NASA has confirmed that a primary goal
[11:46] of the data analysis from Starship test flights is understanding how this super chilled fuel sloshes when the engines cut off. Mastering this liquid stability is the key to ensuring a steady input for the Raptors when they relight in the
[12:00] for the Raptors when they relight in the vacuum of space. On April 21st, 2026, a Falcon 9 booster touched down on the drone ship. Just read the instructions drone ship. Just read the instructions for the 156th time and for the last time
[12:13] in history. Almost immediately, SpaceX announced that the vessel would be reassigned to the Starship program. And that sparked a question across the entire space community. Is this the first step toward preparing drone ships
[12:25] for Starship landings? After all, Starship has gone through numerous flight tests without a single landing leg in sight. So, why would a drone ship matter at all? Unless SpaceX is planning to change that. But the answer is
[12:38] becoming increasingly clear. Starship is going to need legs. And when you look at the bigger picture, you start to realize this is no longer an optional design choice. It's inevitable. After Starship flight 12, monitoring stations recorded
[12:53] some eyeopening numbers. The closest station on South Padre Island about 6 milesi away measured sound levels as high as 125 dB, roughly equivalent to a
[13:05] gunshot at close range. Even in Brownsville, 22 mi from the launch site, Brownsville, 22 mi from the launch site, sensors still registered around 117 dB. And that's from just a single test flight. Now, multiply that by SpaceX's
[13:18] long-term vision, thousands of Starship flights per year, millions of tons of payload to orbit. At that scale, the cumulative acoustic impact becomes impossible to ignore. In May 2026, roughly 80 South Texas households filed
[13:33] a lawsuit against SpaceX, alleging that Starship test flights had generated shock waves powerful enough to crack walls, shatter windows, and damage homes miles away. The plaintiffs presented physical evidence of property damage.
[13:47] So, if SpaceX wants to reduce those legal risks while minimizing community impact, the answer is obvious. move the landings out into the open ocean where there are no windows to break and no homeowners waiting to sue. That's one
[13:59] reason landing legs make increasing sense. But honestly, that's still not the strongest argument. Here's the second one. Every time Mechazilla catches a returning Superheavy booster, those steel arms absorb the full load of
[14:12] a 275 ton vehicle, slowing from tens of meters/s to nearly zero in under a second. Those aren't static loads. They're dynamic shock loads. the exact faster than almost anything else in mechanical engineering. Every joint,
[14:29] every rail segment, every hydraulic cylinder accumulates fatigue damage with each catch. Eventually, those components must be inspected, serviced, and replaced. There is no way around that. It's simply physics. The aviation
[14:43] industry learned this decades ago. Every critical component has a certified fatigue life. Once that limit is reached, replacement is mandatory regardless of how healthy the part looks from the outside. If SpaceX launches
[14:55] from the outside. If SpaceX launches 100, 200, or 500 times per year, maintenance. There will be days, potentially weeks, when the tower is offline. And whenever that happens, every vehicle scheduled to return during
[15:08] that window has nowhere to land. The only alternative would be ocean splashdowns. But Dragon was designed for that from day one. Starship wasn't a vehicle covered in thousands of heat shield tiles packed with avionics and
[15:22] complex aft systems cannot be dropped into saltwater and refflown a few days later. Once seawater gets inside, refurbishment becomes a massive undertaking in some cases beyond economical repair. That's the kind of
[15:37] cost and downtime SpaceX cannot afford at airlineike flight rates. At this point, the picture is clear. Starship is getting landing legs. And that raises the next question because not all landing legs are created equal. The legs
[15:51] the same as the legs it needs for a land-based pad. And neither of those eventually need for the moon or Mars. So, the final question everyone wants
[16:03] answered, when will we actually see a Starship with landing legs? The honest answer is not as soon as many people think, but not as far off as many people fear. Starship is currently on generation 53, which made its debut in
[16:17] generation 53, which made its debut in flight 12 in May 2026. V3 is the version designed to carry out real missions, orbital refueling, Starlink deployment, and in the longer term, the groundwork for HLS, but V3 has no legs. Not in the
[16:32] current design, not in any published technical documentation. V3 still relies entirely on Mazilla for Earth return landings. Landing legs will arrive through two parallel development tracks happening simultaneously, not
[16:46] sequentially. The first track is Starship HLS, the variant designed to land on the moon for NASA's Aremis program. This is the version that will have legs the soonest because there is simply no other option. The moon has no
[17:00] mechazilla, no flat concrete pad, and no one standing there to catch the vehicle. SpaceX is targeting an uncrrewed hls demo landing on the lunar surface around mid 2027 ahead of Artemis actually
[17:14] putting humans on the moon under Artemis 4 in 2028. If that timeline holds, and that is a very large if, given that NASA's aerospace safety advisory panel has repeatedly warned that HLS is running significantly behind schedule,
[17:30] then 2027 would mark the first time we see a Starship variant with actual legs standing on a surface that isn't Earth. The second track is Earth landing with legs, including drone ship capability. This will come later, most likely
[17:43] alongside generation VI4. The version SpaceX is targeting for a 2027 debut. V4 will stand roughly 20 m taller than V3, will be considerably more capable, and
[17:56] based on everything SpaceX has signaled, it will be the first version designed for fully autonomous operation, meaning it can land anywhere without needing a it can land anywhere without needing a tower. If EV4 debuts in late 2027, as
[18:09] anticipated, and early flights go smoothly, a drone ship landing attempt with legs could happen sometime around 2028. But SpaceX never commits to hard timelines for things that haven't been officially confirmed. And they've
[18:23] demonstrated more than once that Elon Musk's timelines are best understood as Musk's timelines are best understood as a direction, not a