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How SpaceX is able to achieve its amazing rocket landing accuracy

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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.

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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GM takes latest step to avoid disaster as EV efforts get derailed

There was an even larger step taken this morning, as the Detroit Free Press reported that GM was idling its Factory Zero plant in Michigan until late November, placing about 1,200 workers on indefinite layoff status.

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Credit: GM

General Motors has taken its latest step to avoid financial disaster as its electric vehicle efforts have been widely derailed.

GM’s electric vehicle manufacturing efforts started off hot, and CEO Mary Barra seemed to have a real hold on how the industry and consumers were starting to evolve toward sustainable powertrains. Even former President Joe Biden commended her as being a major force in the global transition to EVs.

However, the company’s plans have not gone as they’ve drawn them up. GM has reported some underwhelming delivery figures in recent quarters, and with the loss of the $7,500 tax credit, the company is planning for what is likely a substantial setback in its entire EV division.

Earlier this month, the company reported it would include a $1.6 billion charge in its quarterly earnings results from EV investments. It was the first true sign that things with GM’s EV projects were going to slow down.

There was an even larger step taken this morning, as the Detroit Free Press reported that GM was idling its Factory Zero plant in Michigan until late November, placing about 1,200 workers on indefinite layoff status.

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This is in addition to the 280 employees it has already laid off after production cuts that happened earlier this year at the Detroit-Hamtramck plant.

After November 24, GM will bring back 3,200 people to work until January 5 to operate both shifts. On January 5, GM is expected to keep 1,200 workers on indefinite layoff.

GM is not the only legacy automaker to make a move like this, as Ford has also started to make a move that reflects a cautious tone regarding how far and how committed it can be to its EV efforts.

After the tax credit was lost, it seemed to be a game of who would be able to float their efforts longest without the government’s help. Tesla CEO Elon Musk long said that the loss of these subsidies would help the company and hurt its competitors, and so far, that is what we are seeing.

Elon Musk was right all along about Tesla’s rivals and EV subsidies

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However, Tesla still has some things to figure out, including how its delivery numbers will be without the tax credit. Its best quarter came in Q3 as the credit was expiring, but Tesla did roll out some more affordable models after the turn of the quarter.

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Tesla expands Robotaxi geofence, but not the garage

This has broadened its geofence to nearly three times the size of Waymo’s current service area, which is great from a comparative standpoint. However, there seems to be something that also needs to be expanded as the geofence gets larger: the size of the Robotaxi fleet.

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Credit: Joe Tegtmeyer | X

Tesla has expanded its Robotaxi geofence four times, once as recently as this week.

However, the company has seemingly kept its fleet size relatively small compared to the size of the service area, making some people — even pro-Tesla influencers — ask for more transparency and an expansion of the number of vehicles it has operating.

Over the past four months, Tesla has done an excellent job of maintaining growth with its service area in Austin as it continues to roll out the early stages of what is the Robotaxi platform.

The most recent expansion brought its size from 170 square miles (440.298 sq. km) to 243 square miles (629.367 sq. km).

Tesla sends clear message to Waymo with latest Austin Robotaxi move

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This has broadened its geofence to nearly three times the size of Waymo’s current service area, which is great from a comparative standpoint. However, there seems to be something that also needs to be expanded as the geofence gets larger: the size of the Robotaxi fleet.

Tesla has never revealed exactly how many Model Y vehicles it is using in Austin for its partially driverless ride-hailing service (We say partial because the Safety Monitor moves to the driver’s seat for freeway routes).

When it first launched Robotaxi, Tesla said it would be a small fleet size, between 10 and 20 vehicles. In late August, after its second expansion of the service area, it then said it “also increased the number of cars available by 50 percent.”

Tesla reveals it has expanded its Robotaxi fleet in Austin

The problem is, nobody knows how many cars were in the fleet to begin with, so there’s no real concrete figure on how many Robotaxis were available.

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This has caused some frustration for users, who have talked about the inability to get rides smoothly. As the geofence has gotten larger, there has only been one mentioned increase in the fleet.

Tesla did not reveal any new figures or expansion plans in terms of fleet size in the recent Q3 Earnings Call, but there is still a true frustration among many because the company will not reveal an exact figure.

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Tesla recalls 6,197 Cybertrucks for light bar adhesive issue

On October 20, Tesla issued a voluntary recall of the impacted vehicles and has identified 619 warranty claims and just a single field report that is related to the issue. 

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Credit: Francisco Garcia (via Greggertruck on X)

Tesla has recalled 6,197 Cybertrucks for a light bar adhesive issue that was utilized by Service to install the aftermarket part.

According to the National Highway Traffic Safety Administration (NHTSA), impacted vehicles may have had the light bar “inadvertently attached to the windshield using the incorrect surface primer.”

Tesla identified an issue with the light bar’s adhesion to glass back in February and worked for months to find a solution. In October, the company performed chemical testing as a part of an engineering study and determined the root cause as the BetaPrime primer it utilized, figuring out that it was not the right surface priming material to use for this specific application.

On October 20, Tesla issued a voluntary recall of the impacted vehicles and has identified 619 warranty claims and just a single field report that is related to the issue.

The component is manufactured by a Romanian company called Hella Romania S.R.L., but the issue is not the primer’s quality. Instead, it is simply the fact that it is not the correct adhesive for this specific type of application.

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Tesla says there are no reports of injuries or deaths due to this issue, and it will be resolved. In the 473 report that the NHTSA released this morning, Tesla said:

“At no charge to customers, Tesla will inspect the service-installed optional off-road light bar accessory for delamination or damage and if either is present, replace the light bar with a new light bar adhered with tape and a positive mechanical attachment. If no delamination or damage is present, Tesla will retrofit the service-installed optional off-road light bar accessory with a positive mechanical attachment.”

This is the third recall applied to Cybertrucks this year, as one on March 18 highlighted the potential for exterior trim panels to detach while driving, and another earlier this month when the NHTSA said its front parking lights were too bright.

Tesla resolved the first with a free assembly replacement, while the headlight issue was fixed with an Over-the-Air software update earlier this week. Owners said there was a noticeable difference in the brightness of the lights now compared to previously.

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