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How SpaceX is able to achieve its amazing rocket landing accuracy

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8 years ago

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After SpaceX’s successful and uniquely exciting launch of Taiwan’s Formosat-5 remote sensing satellite, Elon Musk took to Twitter to reveal some fascinating details about the launch and recovery of the Falcon 9 first stage.

Unabashedly technical, the details Musk revealed demonstrate the truly incredible accuracy of Falcon 9’s recovery, honed over 20 landing attempts and numerous modifications to the launch vehicle. The accuracy is best understood within the context of Falcon 9’s scale and the general scope of orbital rocketry.

The first stage of Falcon 9 Full Thrust, currently the active version of Falcon 9, stands 140 feet tall and 12 feet in diameter. If you can, for a moment, picture a 737 airliner, the plane most people have likely flown aboard on domestic flights. The first stage of Falcon 9 is the same length or greater and the same diameter as Boeing’s workhorse airliner. If you are now imagining a 737 landing on its tail aboard an ocean-going barge, that is a great start. The most common version of the 737, the -800, has an empty weight of 91,000 lb, while Falcon 9’s empty first stage is a bit more than half as heavy. With a full load of fuel, Falcon 9 S1 (first stage) weighs nearly three times as much as the 737-800. A single Merlin 1D engine out of Falcon 9’s namesake nine rocket engines has nearly ten times the thrust of the airliner. In short, Falcon 9’s first stage is massive, both extremely light and extremely heavy, and has a mind-boggling amount of thrust.

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Falcon 9’s ability to land as accurately as it does is due to a combination of multiple technologies and vehicle modifications. Most visible are S1’s cold gas maneuvering thrusters and aluminum or titanium grid fins, both of which are designed to provide some level of control authority and maneuverability to the first stage during its trip within and without Earth’s atmosphere. At the peak of its trips, the first stage is often completely outside of the vast majority of the atmosphere, meaning that aerodynamic forces are no longer relevant or useful for the vehicle. This is where the cold gas thrusters come in: by carrying their reaction mass with them (the gas), Falcon 9 can maneuver outside of the atmosphere. Once the stage descends into thicker atmospheric conditions, the grid fins deploy and are used like wings to guide the stage down to its landing location, be that on land or at sea. While the gas thrusters lose a lot of their utility once in the atmosphere, they can still be used to add a small amount of control authority when needed. They were famously seen fighting a futile battle to save a first stage aboard OCISLY in 2015.

With this in mind, we can take a closer look at Musk’s technical details. First off, we have a photo of the landed booster, Falcon 9 1038, clearly almost dead center on the droneship Just Read The Instructions. More specifically, Musk reports that 1038 landed less than a single meter off the center of the target, and it landed with less than a single meter per second of latent velocity. The first stage thus managed both a soft and deadly accurate landing after traveling to a height of 150 miles – well into what is technically “space” – at a maximum speed of 1.5 miles per second. Without delving further into the details, this is best summarized as “insanely fast”, and is a bit faster than the X-15 rocketplane’s fastest recorded speed. To better put this into context, Falcon 9 1038 traveled to an altitude of 240,000 meters at a top speed of 2,400 meters per second, turned around, and landed on an autonomous barge about two feet off of its optimal target. It is truly difficult to describe how impressive that kind of accuracy is.

The hypersonic X-15 and Falcon 9 S1, with a 737-800 on the right. All vehicles are to scale. (Wikipedia, SpaceX)

Mr. Musk nevertheless did not let 1038 steal all the fanfare, and revealed that the first stage responsible for launching BulgariaSat-1, 1029, had the honor of being the fastest first stage yet, clocking in at at a truly staggering Mach 7.9, or 2,700 meters per second. That speedy mission marked the stage’s second flight and was SpaceX’s second successful reuse of a Falcon 9. Indicative of the intense speed and heat the core experienced, one of the vehicle’s grid fins was noted to have almost completely melted through. Aluminum’s melting point begins at 1,221°F.

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Eric Ralph is Teslarati's senior spaceflight reporter and has been covering the industry in some capacity for almost half a decade, largely spurred in 2016 by a trip to Mexico to watch Elon Musk reveal SpaceX's plans for Mars in person. Aside from spreading interest and excitement about spaceflight far and wide, his primary goal is to cover humanity's ongoing efforts to expand beyond Earth to the Moon, Mars, and elsewhere.

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U.S. AG Pam Bondi: Tesla Molotov attack suspect facing up to 20 years in prison

The U.S. Attorney General confirmed that a Tesla attacker, who threw Molotov cocktails at a store, is now facing up to 20 years in prison.

Published

15 hours ago

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March 14, 2025

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The White House, Public domain, via Wikimedia Commons
President Donald J. Trump purchases a Tesla on the South Lawn, Tuesday, March 11, 2025. (Official White House Photo by Molly Riley)

It appears that an anti-Tesla activist who is suspected of throwing Molotov cocktails at one of the electric vehicle maker’s stores is now looking at a potentially long prison sentence. 

This is, at least, as per United States Attorney General Pam Bondi, who recently shared her insights in a FOX News segment.

Tesla Attacks and Trump Warning

Tesla locations and vehicles have been subjected to numerous attacks as of late, from stores being shot up to vehicles being vandalized and set on fire in suspected arson incidents. In one case, a Tesla store in Salem, Oregon, was attacked with Molotov cocktails.

President Donald Trump has issued a stern warning to people attacking Teslas, stating that he considers such actions as domestic terrorism. While addressing the issue, Trump warned that anyone caught deliberately harming Tesla will be going through “hell.”

Attorney General’s Update

During a recent FOX News segment, US Attorney General Pam Bondi reiterated that anyone targeting others over political beliefs would be caught and punished accordingly. She highlighted that investigations are underway to find out who is behind the violent actions, and she also confirmed that a Tesla attacker, who threw Molotov cocktails at a store, is now facing up to 20 years in prison.

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“If you targeted someone, if you went after someone because of their political affiliation, we will be investigating you. We will be looking at you, because that’s the weaponization, and it has to stop. For instance, look what they’re continuing to do to Elon Musk. They are targeting Tesla dealerships, the stations where you charge a Tesla. They’re vandalizing cars. I have already directed an investigation be opened to see how this is being funded. Who is behind this? 

“We have people we’re locking up on that. We have someone in jail right now from one of the dealerships. They threw a Molotov cocktail through a dealership. They’re looking at up to 20 years in prison. So, if you’re going to touch a Tesla, go to a dealership, or do anything, you better watch out, because we’re coming after you. And if you’re funding this, we’re coming after you. We’re going to find out who you are,” Bondi stated.

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SpaceX readies to rescue astronauts from International Space Station

Published

15 hours ago

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March 14, 2025

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Credit: SpaceX

SpaceX is readying to launch the Crew-10 mission this evening, which will bring home U.S. astronauts Butch Wilmore and Suni Williams, who have been stuck on the International Space Station for nine months.

SpaceX is working alongside NASA to bring the two astronauts home, and all systems and weather conditions are looking ideal to launch the mission this evening from the Kennedy Space Center in Florida.

Boeing was originally tasked with the rescue mission.

The company sent a Starliner aircraft to the ISS in late September in an effort to bring Williams and Wilmore home. However, malfunctioning thrusters and other issues on the Starliner aircraft prevented NASA from giving the green light to the astronauts to board and come home.

SpaceX was then tasked with bringing the two home, and it appears they will be on their way shortly.

The launch was intended to occur on Wednesday, but a last-minute problem with the rocket’s ground systems forced SpaceX and NASA to delay until at least Friday. Things are looking more ideal for a launch this evening.

The launch is targeted for 7:03 p.m. ET, but another backup opportunity is available tomorrow, March 15, at 6:41 p.m.

SpaceX writes about the Dragon spacecraft that will be used for the mission:

“The Dragon spacecraft supporting this mission previously flew NASA’s Crew-3, Crew-5, and Crew-7 missions to and from the space station. This will be the second flight for the first stage booster supporting this mission, which previously launched the SES 03b mPOWER-e mission. Following stage separation, Falcon 9’s first stage will land on Landing Zone 1 (LZ-1) at Cape Canaveral Space Force Station.”

The mission will not only aim to bring the two astronauts who have been stranded for nine months home, but it will also conduct new research to prepare for human exploration beyond low-Earth orbit.

If Crew-10 launches at the planned time this evening, it will dock to the ISS at 11:30 p.m. ET on Saturday night.

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Tesla discontinues legacy Model Y in the U.S. for custom order

Published

17 hours ago

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March 14, 2025

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(Credit: Tesla)

Tesla has officially wrapped up the ability to order the legacy Model Y in the United States, now only showing the new “Juniper” version and its Launch Series trim in the Online Design Studio.

Tesla launched the new Model Y in the United States in early February, and deliveries of the vehicle have officially started. While other trims of the new-look Model Y are available in other countries, Tesla has not started offering those in the United States quite yet.

However, the legacy Model Y and its several configurations are now no longer available for purchase in the U.S., at least for a custom order. Those who are looking for a deal on the best-selling car in the world for the past two years can still snag whatever is left in inventory.

The sunsetting of the legacy Model Y is the closing of a chapter that truly launched Tesla into the stratosphere.

Although the Model 3 found plenty of mainstream success for Tesla in its first few years, the Model Y was the vehicle that really made the company successful. It disrupted the operations of other companies, and, in conjunction with the Model Y, made OEMs take EVs seriously.

The Model Y was the best-selling vehicle in the world in 2023 and 2024. With the improvements to ride comfort, suspension, and cabin noise, along with the various changes to the exterior, Tesla has a chance to continue its run with the Model Y in 2025 — as long as it can ramp production in a timely manner and keep demand up.

The latter does not seem like it will be a huge problem as it is still a high-demand vehicle.

Tesla unveiled the Model Y on March 15, 2019, so its first design was eliminated nearly five years before its initial appearance.

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