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SpaceX stress-tests Starship-catching arms with giant water balloons
SpaceX has begun testing Starbase’s rocket-catching arms with ballast to simulate the weight of Starship and Super Heavy.
SpaceX started the process of proof testing those arms about a week ago, beginning with some basic calibration work. Together, the three arms and launch tower amount to a giant custom-built robot that SpaceX CEO Elon Musk has deemed “Mechazilla.” Controlled with a complex system of hydraulic and electromechanical actuators spread throughout each structure, SpaceX must calibrate all of those devices to enable the full range of motion the arms are meant to be capable of. To do so, SpaceX appeared to actuate both catch arms (also known as “chopsticks”) as far as they were able to move on January 4th, producing data that could be fed back into the system’s control software to properly set limits of motion.
A handful of days later, arm testing continued, with SpaceX lifting the carriage higher than it had traveled before and demonstrating more complex longitudinal movements that required synchronized motion of both arms. On January 9th, SpaceX performed the most ambitious arm testing yet, nearly lifting the arms to the top of their ~140 meter (~460 ft) tall launch tower backbone to simulate the range of vertical motion required to lift and stack Starship and Super Heavy.
SpaceX also installed a temporary frame meant to simulate a Starship or Super Heavy booster, foreshadowing additional testing planned in the coming days. That jig upped the stakes for the longitudinal actuation portion of January 9th’s testing, as anything less than the precise, synchronized movement of both arms could have caused the heavy steel frame to fall hundreds of feet onto a range of equipment and structures directly below it. Thankfully, the arms performed well and returned to their resting position without issue.
On January 11th, SpaceX proceeded to install six ‘water bags’ – three to a side – on the Starship simulator frame. Amounting to giant, heavy-duty water balloons, those bags are routinely used to stress-test large structures and devices by simulating payloads that might be too expensive or inconvenient to use solely for testing purposes. With those seemingly empty bags attached, SpaceX proceeded to move the catch arms up and down the full length of the launch tower at record speed, taking about seven minutes to climb and descend ~120 meters (~400 ft) – averaging a brisk 0.6 mph or 1 km/h.
Here is a video from Giga Texas of this type of mass simulator! pic.twitter.com/uHfah45WVt— Zack Golden (@CSI_Starbase) January 11, 2022
On January 12th, SpaceX filled the balls with water, producing some… interesting… visuals. Ridiculous appearances aside, the six bags SpaceX chose to use could be 20, 35, or 50-ton variants, meaning that all six could weigh anywhere from 120 to 300 tons (264,000-660,000 lb) if fully filled. In other words, perfect for simulating the dry masses of Starship (roughly 80-120 tons) and Super Heavy (150-200+ tons).
SpaceX did appear to fully fill around four of the six bags and partially filled the other two, causing the whole arm structure to visibly sag during the fill process as the weight of the ballast stretched the several-inch-thick steel cable holding the whole device aloft. In the late afternoon, the laden arms lifted around 10-20 meters and rotated left and right, partially demonstrating the process of rotating a lifted Starship or Super Heavy into position for stacking or launch mount installation. They were never lifted high enough to truly demonstrate that ability, though, and were lowered back to the ground soon after.
As of 10pm CST, January 12th, the water bags appear to have been fully drained after their first excursion. It’s likely that load-testing will continue over the next several days or weeks – SpaceX may just want to avoid leaving the arms fully loaded overnight.
A Tesla Semi caught fire in Hayward, California, which caused both directions of traffic to shut down for hours before being completely reopened early on Wednesday, the California Highway Patrol said.
The fire occurred just after 5:30 local time in Hayward on Tuesday, as the Semi caught fire in the southbound lanes of I-880 before CHP officials made the decision to shut down both lanes of traffic due to potential risks from hazardous chemical smoke.
There were no injuries reported.
🚨 A Tesla Semi reportedly caught fire, with California Highway Patrol confirming. The Semi was on I-880 SB
An estimated 5,000 to 7,000 semi-truck and large commercial vehicle fires occur on U.S. roadways every year
— TESLARATI (@Teslarati) October 28, 2026
The cause of the fire is currently unknown, as neither Tesla nor the CHP have not determined a cause.
However, some images taken before the Semi was completely destroyed by the fire seem to indicate this might have been an older unit, as it appears to be one of the designs that Tesla shipped as part of its pilot program, before revising it and starting mass production just a month ago.
@Tslachan From on of the videos looks like it’s an old Semi (not the refresh version that recently started production) https://t.co/KzwmR2kXow
— Area Under The Curve 🎗️ (@AreaUnderCurve) October 28, 2026
At the time of publication, CHP had not returned our request for a comment for additional details, including the Semi involved and any potential collaboration on an investigation between the CHP and Tesla. We will update this story when we hear back from them.
The southbound lanes were reopened at 3:30 a.m. on Wednesday, with the northbound lanes opening last night a few hours after the fire began. The CHP did state that the lithium batteries were “incredibly difficult to extinguish,” according to NBC Bay Area.
The truck’s driver said that the Semi caught fire, but he did not have an explanation.
An estimated 5,000 to 7,000 semi-truck and large commercial vehicle fires occur on U.S. roadways every year.
Tesla’s launch of the “Emergency Drive Away” function a few months back offered owners a safe option to evacuate an area if they were in reasonable danger. The function finally got its first use in the real world, but it appears it was by mistake.
A video shared by u/Joshalander in the r/TeslaLounge subreddit recorded the instance from his vehicle and said the incident took place in Austin this past weekend during the city’s F1 Race.
“Was charging around 6 AM this past Sunday in Austin before heading to the F1 race and heard a pop. Looked over and saw the new emergency drive-away feature in action. Genuinely felt bad for the dude when he got out and realized what happened, since he looked exhausted and only seemed to half-read the prompts.”
🚨 Here’s the first look at Tesla’s Emergency Drive Away function in action:
Apparently this driver accidentally enabled it and drove forward; you can see the Supercharger pull with the car.
Tesla said previously this would cost up to $25k if not used properly. https://t.co/B4qQRrsO6B
— TESLARATI (@Teslarati) October 28, 2026
Emergency Drive Away unlatches the Supercharger connector from the vehicle, but still causes damage to both the car and the Supercharger. Tesla has said that it will cost up to $25,000 in repairs to have everything fixed back to normal.
Additionally, the company said that if it were not used in an emergency situation, the driver of the vehicle who activated the Emergency Drive Away feature would be responsible for all repair costs.
Tesla constitutes the following situations as reasonable justifications for activating the feature:
- You face an immediate threat to your life or personal safety.
- You must leave the area immediately.
- Exiting the vehicle is unsafe.
- Unplugging the charge connector would unreasonably delay your departure or expose you to a risk to your personal safety.
After using the feature, Tesla requires the driver to schedule Service so the car can be inspected.
News
Tesla’s Cybercab battery design could make robotaxis even cheaper
Tesla built the Cybercab’s battery pack with spare room for a future switch to LFP.
Tesla built the Cybercab’s battery pack with empty space inside it on purpose, and the reason points to a cheaper robotaxi down the road.
Robert Sumpf, Tesla’s director of mechanical design engineering for battery modules and packs, said the extra room beside and beneath the Cybercab’s modules was left there so the company can move to lithium iron phosphate cells later. “So, we protected this pack to go to an even lower energy dense chemistry as we scale and need to bring LFP into the platform,” Sumpf said in a Cybercab deep dive with Munro Live.
The Cybercab runs on Tesla’s own 4680 cells with a nickel chemistry today. LFP cells store less energy for their size, so a straight swap would cut range. The reserved space lets Tesla add more LFP cells to make up the difference. In return, Tesla would get cells that cost less, run cooler and survive more charge cycles. LFP became the most used EV battery chemistry in the world last year.
Not all of that room was planned for a chemistry change. Lars Moravy, Tesla’s Vice President of Vehicle Engineering, said part of it exists because “we didn’t need as many batteries as we thought we did.” Tesla told Sandy Munro in early 2025 that it was targeting a Cybercab pack under 50 kWh with close to 300 miles of range.
The pack also breaks from the structural design Tesla used in some Model Y and Cybertruck builds. Instead of potting hundreds of cells into one block, the Cybercab uses four separate, individually sealed modules, so a bad module can be replaced without scrapping the whole pack. Sumpf was blunt about the older approach, giving the Model Y structural battery “a grade D” because it was hard to build and nearly impossible to repair. He estimated a fully structural pack gains about 10% more cell volume, but said “the issue is the service cost.”
That cost matters more for a car that rarely sits parked. Cybercab chief engineer Eric Earley said replacing an entire pack “before half a million miles is a killer on cost,” which is why remanufacturing and serviceability were built into the design from the start.
The same Munro Live tour produced Moravy’s admission that the Cybercab line at Giga Texas is now outpacing Robotaxi deployments, along with a look at the robotaxi’s unorthodox paint process. Tesla is aiming to deliver the first Cybercabs to outside customers by the end of 2026, though Elon Musk has said the vast majority will stay owned by Tesla and run as a transport service.
Sumpf did not give a date for an LFP version, name a cell supplier or say how a chemistry change would affect range. For now, the 4680 cars keep piling up: Texas DMV records from Tuesday list 544 Cybercabs authorized for Tesla’s Robotaxi fleet, more than the 507 Model Ys on the same roster for the first time.
Tesla Semi catches fire in California: what we know
Tesla’s ‘Emergency Drive Away’ function gets its first use in the real world
