After rapidly stacking Ship 20 and Booster 4 the evening prior, SpaceX appears to have begun testing a fully stacked Starship rocket for the first time ever.
Though the test SpaceX subjected Starship to was by no means ambitious and in spite of the fact that it no longer appears that Ship 20 and Booster 4 will ever fly, the first test of the first fully integrated prototype of a new rocket is still an immensely significant achievement – particularly so for the largest rocket ever built.
Standing around 119 meters (~390 ft) tall, Starship is unequivocally the largest and most voluminous rocket ever built. With its 29 Raptor V1 engines, the fully assembled Ship 20 and Booster 4 (B4) stack would have likely weighed around 4000-5000 tons (9-11M lb) and been able to produce around 5400 tons (11.9M lbf) of thrust at liftoff – substantially heavier and more powerful than Saturn V or N1, the largest rockets ever successfully and unsuccessfully launched.
For its first fully-integrated test, though, SpaceX appears to have put Starship through a fairly limited cryogenic proof – a test where flammable propellant is replaced with a similarly cold (cryogenic) fluid that’s similar enough to subject a rocket to similar thermal and mechanical stresses. For Ship 20 and Booster 4’s combined debut, Super Heavy was filled maybe 10-20% and Starship around 25-50% of the way with either liquid nitrogen (LN2) or a combination of LN2 and liquid oxygen (LOx). It’s difficult to tell but it’s unlikely any methane (LCH4) fuel was involved.
Back on the ground, Starship S20 completed five separate cryogenic proof tests before its first test on top of Super Heavy. More importantly, Ship 20 successfully completed several static fire tests, each of which also functioned as a wet dress rehearsal with LCH4/LOx propellant. Booster 4 had also passed several cryogenic proof tests. In that sense, it’s unlikely that SpaceX had a great deal of uncertainty as to whether either prototype would be able to complete yet another test.
Beyond the basic mechanical demonstration that Super Heavy Booster 4 is strong enough to support a partially loaded Starship, which probably wasn’t in doubt, it’s likely that the main purpose of this first full-stack cryoproof was to ensure that all the systems required to fuel Starship on top of Super Heavy were working as expected. That’s no small feat given that Starship is both the tallest rocket and largest upper stage ever assembled. To fully fuel a Starship for an orbital launch, around 1200 tons (~2.65M lb) of propellant (or LN2 for a cryoproof) – equivalent to the weight of more than two entire Falcon 9 rockets – must be pumped around 85 meters (~275 ft) up Starbase’s integration tower.
That requires thousands of feet of plumbing and a symphony of giant valves and pumps, all of which must work in concert – without leaking, jamming, or freezing – to fuel Starship. As such, the first full-stack cryoproof was just as much – or more – of a test of the orbital launch site’s launch/integration tower and tank farm. That first test is just the start of a long process, though, and it’s likely that SpaceX will attempt an increasingly ambitious series of tests with Booster 4 and Ship 20 over the next week or two.
That could involve simply filling the rocket further and raising its tank pressures or it could potentially culminate in a partial wet dress rehearsal with methane and oxygen propellant in place of liquid nitrogen. There’s an even smaller chance that SpaceX could attempt to static fire Super Heavy B4 for the first time, although sources like NASASpaceflight are no longer confident that Booster 4 will be static fired before retirement. More to the point, it would be uncharacteristically risky behavior from SpaceX to perform the very first static fire of a new prototype with an already proven Starship sitting on top of it. An anomaly as small as an uncontrolled fire – far from uncommon for Starships – could easily risk the catastrophic destruction of both stages, which would itself run the risk of significantly damaging the orbital launch site, which could easily take months to repair.
Nonetheless, there’s still a chance. SpaceX has opportunities for additional testing on March 17th, 18th, 21st, and 22nd.
Investor's Corner
SpaceX IPO is coming, CEO Elon Musk confirms
However, it appears Musk is ready for SpaceX to go public, as Ars Technica Senior Space Editor Eric Berger wrote an op-ed that indicated he thought SpaceX would go public soon. Musk replied, basically confirming it.
Elon Musk confirmed through a post on X that a SpaceX initial public offering (IPO) is on the way after hinting at it several times earlier this year.
It also comes one day after Bloomberg reported that SpaceX was aiming for a valuation of $1.5 trillion, adding that it wanted to raise $30 billion.
Musk has been transparent for most of the year that he wanted to try to figure out a way to get Tesla shareholders to invest in SpaceX, giving them access to the stock.
He has also recognized the issues of having a public stock, like litigation exposure, quarterly reporting pressures, and other inconveniences.
However, it appears Musk is ready for SpaceX to go public, as Ars Technica Senior Space Editor Eric Berger wrote an op-ed that indicated he thought SpaceX would go public soon.
Musk replied, basically confirming it:
As usual, Eric is accurate
— Elon Musk (@elonmusk) December 10, 2025
Berger believes the IPO would help support the need for $30 billion or more in capital needed to fund AI integration projects, such as space-based data centers and lunar satellite factories. Musk confirmed recently that SpaceX “will be doing” data centers in orbit.
AI appears to be a “key part” of SpaceX getting to Musk, Berger also wrote. When writing about whether or not Optimus is a viable project and product for the company, he says that none of that matters. Musk thinks it is, and that’s all that matters.
It seems like Musk has certainly mulled something this big for a very long time, and the idea of taking SpaceX public is not just likely; it is necessary for the company to get to Mars.
The details of when SpaceX will finally hit that public status are not known. Many of the reports that came out over the past few days indicate it would happen in 2026, so sooner rather than later.
But there are a lot of things on Musk’s plate early next year, especially with Cybercab production, the potential launch of Unsupervised Full Self-Driving, and the Roadster unveiling, all planned for Q1.
Tesla has added the 15th automaker to the growing list of companies whose EVs can utilize the Supercharger Network this year, as BMW is the latest company to gain access to the largest charging infrastructure in the world.
BMW became the 15th company in 2025 to gain Tesla Supercharger access, after the company confirmed to its EV owners that they could use any of the more than 25,000 Supercharging stalls in North America.
Welcome @BMW owners.
Download the Tesla app to charge → https://t.co/vnu0NHA7Ab
— Tesla Charging (@TeslaCharging) December 10, 2025
Newer BMW all-electric cars, like the i4, i5, i7, and iX, are able to utilize Tesla’s V3 and V4 Superchargers. These are the exact model years, via the BMW Blog:
- i4: 2022-2026 model years
- i5: 2024-2025 model years
- 2026 i5 (eDrive40 and xDrive40) after software update in Spring 2026
- i7: 2023-2026 model years
- iX: 2022-2025 model years
- 2026 iX (all versions) after software update in Spring 2026
With the expansion of the companies that gained access in 2025 to the Tesla Supercharger Network, a vast majority of non-Tesla EVs are able to use the charging stalls to gain range in their cars.
So far in 2025, Tesla has enabled Supercharger access to:
- Audi
- BMW
- Genesis
- Honda
- Hyundai
- Jaguar Land Rover
- Kia
- Lucid
- Mercedes-Benz
- Nissan
- Polestar
- Subaru
- Toyota
- Volkswagen
- Volvo
Drivers with BMW EVs who wish to charge at Tesla Superchargers must use an NACS-to-CCS1 adapter. In Q2 2026, BMW plans to release its official adapter, but there are third-party options available in the meantime.
They will also have to use the Tesla App to enable Supercharging access to determine rates and availability. It is a relatively seamless process.
News
Tesla adds new feature that will be great for crowded parking situations
This is the most recent iteration of the app and was priming owners for the slowly-released Holiday Update.
Tesla has added a new feature that will be great for crowded parking lots, congested parking garages, or other confusing times when you cannot seem to pinpoint where your car went.
Tesla has added a new Vehicle Locator feature to the Tesla App with App Update v4.51.5.
This is the most recent iteration of the app and was priming owners for the slowly-released Holiday Update.
While there are several new features, which we will reveal later in this article, perhaps one of the coolest is that of the Vehicle Locator, which will now point you in the direction of your car using a directional arrow on the home screen. This is similar to what Apple uses to find devices:
Interesting. The location arrow in the Tesla app now points to your car when you’re nearby. pic.twitter.com/b0yjmwwzxN
— Whole Mars Catalog (@wholemars) December 7, 2025
In real time, the arrow gives an accurate depiction of which direction you should walk in to find your car. This seems extremely helpful in large parking lots or unfamiliar shopping centers.
Getting to your car after a sporting event is an event all in itself; this feature will undoubtedly help with it:
The nice little touch that Tesla have put in the app – continuous tracking of your vehicle location relative to you.
There’s people reporting dizziness testing this.
To those I say… try spinning your phone instead. 😉 pic.twitter.com/BAYmJ3mzzD
— Some UK Tesla Guy (UnSupervised…) (@SomeUKTeslaGuy) December 8, 2025
Tesla’s previous app versions revealed the address at which you could locate your car, which was great if you parked on the street in a city setting. It was also possible to use the map within the app to locate your car.
However, this new feature gives a more definitive location for your car and helps with the navigation to it, instead of potentially walking randomly.
It also reveals the distance you are from your car, which is a big plus.
Along with this new addition, Tesla added Photobooth features, Dog Mode Live Activity, Custom Wraps and Tints for Colorizer, and Dashcam Clip details.
🚨 Tesla App v4.51.5 looks to be preparing for the Holiday Update pic.twitter.com/ztts8poV82
— TESLARATI (@Teslarati) December 8, 2025
All in all, this App update was pretty robust.
SpaceX IPO is coming, CEO Elon Musk confirms
Tesla adds 15th automaker to Supercharger access in 2025
