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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.

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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.

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.

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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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Tesla reveals huge Cybercab detail in new guide for First Responders

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Credit: Tesla

Tesla revealed a major new Cybercab detail in a guide it released for First Responders, showing new territory in its beliefs and intentions for the ride-hailing-focused vehicle that entered production in April.

The First Responders Guide is released to give fire departments, paramedics, and other emergency personnel the proper guidance on what to do in the event of an accident, entrapment, or other situation that would require immediate attention.

On one of the pages of the First Responders Guide, Tesla revealed a stark detail about the Cybercab, which could help personnel enter the vehicle more easily in case of an emergency.

Tesla Cybercab has one important piece that AI4 cars might need for FSD

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It shows Tesla has no intention of releasing any Cybercab units that were initially proposed for ride-hailing services for the general public with any manual controls, meaning a steering wheel or pedals:

“A Cybercab equipped with steering wheel, brake pedal, and an acceleration pedal is typically an engineering or test vehicle, and operates at SAE Level 2 autonomy. Cybercab is not typically equipped with a steering wheel or acceleration and brake pedals.”

This is a major development for those who continue to believe Tesla planned to release the Cybercab with any sort of manual controls so that passengers could take over if needed. However, when Tesla started manufacturing production versions of the Cybercab in Giga Texas earlier this year, they were spotted without a steering wheel or pedals.

It essentially confirms the company has no intentions of bringing manual controls to the car’s production versions. Some have argued that the likelihood of Tesla having something

There still are some Cybercab units out there with a steering wheel and pedals, and as Tesla said, these cars are engineering or test vehicles, which have Safety Monitors on board to help the car out of a precarious situation or emergency.

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Tesla Full Self-Driving v14 ‘Lite’ Release Notes: new capabilities and features

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(Credit: Megan Gale/Twitter)

Tesla released the Full Self-Driving v14 ‘Lite’ suite to owners of Hardware 3 or AI3 vehicles today, adding several new features to the vehicles that were once believed to be capable of unsupervised self-driving.

Now, Tesla has released this modified suite to older Tesla vehicles, adding plenty of new features and capabilities.

Here are the full release notes for the suite:

  • Distilled the intelligence from HW4 V14 into HW3. This allows HW3 to directly learn how to handle scenarios using HW4 V14 as a guide. This process unlocks the improvements that have been made to HW4 including Reinforcement Learning (RL) and offline models for HW3.
  • Improved both proactive and reactive responsiveness across a wide variety of categories including navigation handling, merges and forks, pedestrian interactions, traffic lights, and vehicle cut-in scenarios.
  • Improved general comfort in nominal scenarios through fewer false slowdowns, smoother steering and more consistent lane centering.
  • Introduced parking, unparking, and reversing capabilities.
  • Added Arrival Options for you to select where FSD should park: in a Parking Lot, on the Street, in a Driveway, or at the Curbside.
  • Speed Profiles are now available at all times, to further customize driving style preference.

These improvements, according to Tesla’s Head of AI, Ashok Elluswamy, help distill the driving behavior from AI4’s v14 series into both the camera and compute configurations of AI3.

Tesla Full Self-Driving v14 ‘Lite’ for older cars finally gets released

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He added:

“It includes destination options and speed profiles on city roads, but more importantly significantly improved safety. We hope you’ll enjoy it, once the build ships wide.”

Tesla will continue to roll out the v14 Lite suite more widely in the coming weeks, the company said.

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Tesla Full Self-Driving v14 ‘Lite’ for older cars finally gets released

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tesla model 3 model y
Credit: Tesla Inc.

Tesla has finally released its Full Self-Driving v14 ‘Lite’ suite for older cars that equip the Hardware 3 or AI 3 chip, which have not been able to handle the newest versions of the company’s driver assistance software.

Tesla officially started releasing the v14 Lite suite to owners in the Early Access Program last night. The company’s Head of AI, Ashok Elluswamy, said that the rollout will continue over the next few weeks. The build distills the driving behavior from AI4’s v14 series into both the camera and compute configurations of an AI3 car.

It also includes a variety of new features that were available to AI4 cars running v14, including:

  • Start Self-Driving from Park
  • Arrival and Parking Options
  • Speed Profiles

The release is highly anticipated because those owners with AI3 vehicles were early adopters into the FSD platform and were promised that their cars would be capable of achieving Full Self-Driving.

However, Tesla CEO Elon Musk admitted during the company’s recent Q1 Earnings Call that these vehicles would not be capable of achieving unsupervised Full Self-Driving, which is what Tesla had originally said.

Owners were not pleased with this answer, or the idea that their commitment to buying the suite outright for thousands of dollars would not yield the ability to drive without operating the car. Tesla gave some solutions for this, including a discount on a new car, or an upgrade to an AI4 or AI5 self-driving computer and new, upgraded cameras.

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Tesla owners do not seem pleased with these options, as they require giving the company more money.

Nevertheless, it is important to note that Tesla came through for owners here by releasing v14 Lite before the end of Q2, something it had promised owners during the previous Earnings Call. Tesla has had trouble keeping up with timelines, but this is a big achievement for the team.

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