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SpaceX’s path to refueling Starships in space is clearer than it seems

Published

5 years ago

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Perhaps the single biggest mystery of SpaceX’s Starship program is how exactly the company plans to refuel the largest spacecraft ever built after they reach orbit.

First revealed in September 2016 as the Interplanetary Transport System (ITS), SpaceX has radically redesigned its next-generation rocket several times over the last half-decade. Several crucial aspects have nevertheless persisted. Five years later, Starship (formerly ITS and BFR) is still a two-stage rocket powered by Raptor engines that burn a fuel-rich mixture of liquid methane (LCH4) and liquid oxygen (LOx). Despite being significantly scaled back from ITS, Starship will be about the same height (120 m or 390 ft) and is still on track to be the tallest, heaviest, and most powerful rocket ever launched by a large margin.

Building off of years of growing expertise from dozens of Falcon 9 and Falcon Heavy launches, the most important fundamental design goal of Starship is full and rapid reusability – propellant being the only thing intentionally ‘expended’ during launches. However, like BFR and ITS before it, the overarching purpose of Starship is to support SpaceX’s founding goal of making humanity multiplanetary and building a self-sustaining city on Mars. For Starship to have even a chance of accomplishing that monumental feat, SpaceX will not only have to build the most easily and rapidly reusable rocket and spacecraft in history, but it will also have to master orbital refueling.

The reuse/refuel equation

In the context of SpaceX’s goals of expanding humanity to Mars, a mastery of reusability and orbital refueling are mutually inclusive. Without both, neither alone will enable the creation of a sustainable city on Mars. A Starship launch system that can be fully reused on a weekly or even daily basis but can’t be rapidly and easily refueled in space simply doesn’t have the performance needed to affordably build, supply, and populate a city on another planet (or Moon). A Starship launch system that can be easily refueled but is not rapidly and fully reusable could allow for some degree of interplanetary transport and the creation of a minimal human outpost on Mars, but it would probably be one or two magnitudes more difficult, risky, and expensive to operate and would require a huge fleet of ships and boosters from the start.

The question of how SpaceX will make Starship the world’s most rapidly, fully, and cheaply reusable rocket is a hard one, but it’s not all that difficult to extrapolate from where the company is today. Currently, the turnaround record (time between two flights) for Falcon boosters is two launches in less than four weeks (27 days). SpaceX’s orbital-class reuse is also making strides and the company recently flew the same orbital Crew Dragon capsule twice in just 137 days (less than five months) – fast approaching turnarounds similar to NASA’s Space Shuttle average, the only other reusable orbital spacecraft in history.

SpaceX’s current fleet of four reusable Dragon spacecraft. (NASA/Mike Hopkins/ESA/Thomas Pesquet)
Pictured here during its last launch, Falcon 9 B1060 owns SpaceX’s turnaround record of just 27 days and has completed eight orbital-class launches in 12 months, averaging one flight every ~45 days – an average turnaround time that’s better than the Space Shuttle’s all-time record. (SpaceX)

While Dragon and Falcon 9 are far smaller than Starship and Super Heavy, Dragon is only partially reusable and requires significant refurbishment after recovery and Falcon 9 boosters are fairly complex. Starship, on the other hand, should effectively serve as a fully reusable all-in-one Falcon upper stage, Dragon capsule, Dragon trunk, and fairing, making it far more complex but potentially far more reusable. To an extent, Super Heavy should also be mechanically simpler than Falcon boosters (no deployable legs or fins; no structural composite-metal joints; no dedicated maneuvering thrusters) and its clean-burning Raptor engines should be easier to reuse than Falcon’s Merlins. Put simply, there are precedents set and evidence provided by Falcon rockets and NASA’s Space Shuttle that suggest SpaceX will be able to solve the reusability half of the equation.

What about refueling?

The other half of that equation, however, could not be more different. The sum total of SpaceX’s official discussions of orbital refueling can be summed up in a sentence included verbatim in CEO Elon Musk’s 2017, 2018, and 2019 Starship presentations: “propellant settled by milli G acceleration using control thrusters.”

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This phrase first appeared in 2017 (PDF; page 16). (SpaceX)

On the face of it, that simple phrase doesn’t reveal much. However, with a few grains of salt, hints from what the company’s CEO has and hasn’t said, and context from the history of research into orbital propellant transfer, it’s possible to paint a fairly detailed picture of the exact mechanisms SpaceX will likely use to refill Starships in space. The cornerstone, somewhat ironically, is a 2006 paper – written by seven Lockheed Martin employees and a NASA engineer – titled “Settled Cryogenic Propellant Transfer.” Aside from the obvious corollaries just from the title alone, the paper focuses on what the authors argue is the simplest possible route to large-scale orbital propellant transfer.

In orbit, under microgravity conditions, the propellant inside a spacecraft’s tanks is effectively detached from the structure. If a spacecraft applies thrust, that propellant will stay still until it splashes against its tank walls – the most basic Newtonian principle that objects at rest tend to stay at rest. If, say, a spacecraft thrusts in one direction and opens a hatch or valve on the tank in the opposite direction of that thrust, the propellant inside it – attempting to stay at rest – will naturally escape out of that opening. Thus, if a spacecraft in need of fuel docks with a tanker, their tanks are connected and opened, and the tanker attempts to accelerate away from the receiving ship, the propellant in the tanker’s tanks will effectively be pushed into the second ship as it tries to stay at rest.

The principles behind such a ‘settled propellant transfer’ are fairly simple and intuitive. The crucial question is how much acceleration the process requires and how expensive that continuous acceleration ends up being. According to Kutter et al’s 2006 paper, the answer is surprising: assuming a 100 metric ton (~220,000 lb) spacecraft pair accelerates at 0.0001G (one ten-thousandth of Earth gravity) to transfer propellant, they would need to consume just 45 kg (100 lb) of hydrogen and oxygen propellant per hour to maintain that acceleration.

Two possible Starship orientations for propellant transfer. (SpaceX)

In the most extreme hypothetical refueling scenario (i.e. a completely full tanker refueling a ship with a full cargo bay), two docked Starships would weigh closer to 1600 tons (~3.5M lb) and the “Milli G” acceleration SpaceX has repeatedly mentioned in presentation slides would be ten times greater than the maximum acceleration analyzed by Kutter et al. Still, according to their paper, that propellant cost scales linearly both with the required acceleration and with the mass of the system. Roughly speaking, using the same assumptions, that means that the thrusting Starship would theoretically consume just over 7 tons (half a percent) of its methane and oxygen propellant per hour to maintain milli-G acceleration.

With large enough pipes (on the order of 20-50 cm or 8-20 in) connecting each Starship’s tanks, SpaceX should have no trouble transferring 1000+ tons of propellant in a handful of hours. Ultimately, that means that settled propellant transfer even at the scale of Starship should incur a performance ‘tax’ of no more than 20-50 tons of propellant per refueling. All transfers leading up to the worst-case 1600-ton scenario should also be substantially more efficient. Overall, that means that fully refueling an orbiting Starship or depot with ~1200 tons of propellant – requiring anywhere from 8 to 14+ tanker launches – should be surprisingly efficient, with perhaps 80% or more of the propellant launched remaining usable by the end of the process.

On Super Heavy B4, SpaceX has installed what amount to nozzles over the booster’s main oxygen tank vents to vector and maximize the thrust they produce. (NASASpaceflight – bocachicagal)

A step further, Kutter et al note the amount of acceleration required is so small that a hypothetical spacecraft could potentially use ullage gas vents to achieve it, meaning that custom-designed settling thrusters might not even be needed. Coincidentally or not, SpaceX (or CEO Elon Musk) has recently decided to use strategically located ullage vents to replace purpose-built maneuvering thrusters on Starship’s Super Heavy booster. If SpaceX adds similar capabilities to Starship, it’s quite possible that the combination of cryogenic propellant naturally boiling into gas as it warms and the ullage vents used to relieve that added pressure could produce enough thrust to transfer large volumes of propellant.

Last but not least, writing more than a decade and a half ago, the only technological barrier Kutter et al could foresee to large-scale settled propellant transfer wasn’t even related to refueling but, rather, to the ability to autonomously rendezvous and dock in orbit. In 2006, while Russia was already routinely using autonomous docking and rendezvous technology on its Soyuz and Progress spacecraft, the US had never demonstrated the technology on its own. Jump to today and SpaceX Dragon spacecraft have autonomously rendezvoused with the International Space Station twenty seven times in nine years and completed ten autonomous dockings – all without issue – since 2019.

SpaceX has already developed and thoroughly tested hot-gas Raptor-derived maneuvering thrusters that could be fairly easily added to Starship to boost the efficiency of settled propellant transfer at the cost of added weight and complexity. (NASASpaceflight – bocachicagal)

Even though SpaceX and its executives have never detailed their approach to refueling (or refilling, per Musk’s preferred term) Starships in space, there is a clear path established by decades of NASA and industry research. What little evidence is available suggests that that path is the same one SpaceX has chosen to travel. Ultimately, the key takeaway from that research and SpaceX’s apparent use of it should be this: while a relatively inefficient process, SpaceX has effectively already solved the last remaining technical hurdle for settled propellant transfer and should be able to easily refuel Starships in orbit with little to no major development required.

There’s a good chance that minor to moderate problems will be discovered and need to be solved once SpaceX begins to test refueling in orbit but crucially, there are no obvious showstoppers standing between SpaceX and the start of those flight tests. Aside from the obvious (preparing a new rocket for its first flight tests), the only major refueling problem SpaceX arguably needs to solve is the umbilical ports and docking mechanisms that will enable propellant transfer. SpaceX will also need to settle on a location for those ports/mechanisms and decide whether to implement ullage vent ‘thrusters’, cold gas thrusters like those on Falcon and current Starship prototypes, or more efficient hot-gas thrusters derived from Raptors. At the end of the day, though, those are all solved problems and just a matter of complex but routine systems engineering that SpaceX is an expert at.

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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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Cybertruck

Tesla’s most delayed Cybertruck feature is finally here

Tesla finally links Cybertruck Powershare with Powerwall 3 for extended home backup after years overdue.

Published

10 hours ago

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September 10, 2026

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Tesla’s Cybertruck can now pair with a Powerwall 3 to keep a house running longer during an outage, a feature the company first promised when the truck launched in November 2023.

The official Cybertruck account posted the update on X Thursday: “Powerwall 3 & I can now power your house together. This extends your home backup by over 3 days, equivalent to 9 additional Powerwalls,” Cybertruck lead engineer Wes Morrill confirmed the rollout separately, calling it the first time a vehicle and a home battery have worked together this way. Powerwall 2 and Powerwall+ compatibility is still coming later this year, per both the Cybertruck account and Morrill.

Powershare itself is not new. Tesla enabled the version that lets Cybertruck power tools, appliances or another EV through its bed outlets when the truck launched in 2023. Home backup through a Powershare Gateway and Universal Wall Connector arrived in 2024, and Tesla extended that support to homes with solar the following year. What has been missing until now is Powershare working alongside an existing Powerwall, instead of functioning as a separate backup source competing for the same job.

The pairing matters because a single Powerwall home battery typically covers a home for about a day, less if usage is heavy or the outage stretches into a heat wave or freeze. A second Powerwall for more backup storage costs several thousand dollars installed. A Cybertruck instead uses a battery the owner already has, one large enough here to add roughly three more days of backup without mounting another unit or booking an installer visit. For households in wildfire, hurricane or winter storm regions where outages run past a day, that keeps the refrigerator and medical equipment running instead of shutting down.

Tesla provides Cybertruck Powershare release update

The company told owners in October 2024 that Powerwall integration was coming sometime in 2025. That date passed, and in December 2025 Tesla pushed the target to mid-2026, with Morrill explaining at the time that two grid-forming devices need to negotiate which one manages a home during an outage, and that certifying the process across multiple generations of Powerwall took longer than expected.

For owners who bought Powershare hardware expecting it to work with whatever battery setup they already had, Thursday’s update closes a gap that has shown up repeatedly in owner complaints since Cybertruck deliveries began. Tesla has also rolled out a separate Powershare grid support program in Texas, letting Cybertrucks send power back to the grid during high demand events, so the truck’s role in a home’s energy setup keeps expanding even as individual pieces of it arrive later than promised.

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Tesla ruined other cars for me: one year Model Y ownership review

Published

21 hours ago

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September 10, 2026

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Credit: Joey Klender

I picked up my Tesla Model Y one year ago, on August 30, and for roughly a year, I have had this vehicle prove to me that any other carmaker’s product is ruined for me forever.

One year and over 16,000 miles later, the Tesla Model Y is easily the best car I’ve ever had. Of course, everyone always says that about the car they currently drive, but for the longest time, I truly believed some of the other cars I drove — my 1998 Volkswagen Jetta K2, or my 2008 Ford Escape Hybrid — would never be topped.

Most of this was due to nostalgia, but dependability also played a role.

My Tesla has taken over the number one spot. Everyone I talk to about my car always has a lot of questions, and they’re usually the same ones that someone else asked me: “Is it really so cheap to drive?” “How much does it cost to charge?” “Does it really drive itself?” “How long is the warranty on your battery?”

I never mind answering those questions because it is an opportunity to educate someone on EVs. There are a lot of things about EVs that I hear from people, and I can’t help but chuckle at times. However, I hope this review clears some of those things up, because I truly want everyone to know how great this vehicle really is.

How my Tesla has changed my life

I was in two car accidents in high school, and I was a passenger in both. I am very happy I went through those as a teenager, because if I didn’t, I think I’d probably be much less aware of the road, how other drivers are so unbelievably unaware of others, and how inconsiderate most drivers are.

I’ve always considered myself a good driver because I was always taught to be defensive. Because of those two accidents, I am a tad jumpy in passenger seats, even with people like my parents, who drove me around for 16 years before I got my Learner’s Permit. On a drive home from Florida to Pennsylvania with my Dad two years ago, he actually told me at one point to “stop being so jumpy.”

Truth is, I trust my Dad behind the wheel more than anyone. But the older I’ve gotten, the more I just prefer to drive myself.

That is, until I met my Tesla and Full Self-Driving. I still remember the first drive I took after taking delivery: I immediately typed in my Fiancèe’s (my wife in 30 days!!!) favorite lunch spot, picked up her favorite meal, and pulled into the hospital where she delivers babies. I can remember thinking after 15 minutes, “Okay, that’s enough for me; I’ll drive manually now.”

Over the next 2-3 weeks, that length of time slowly but steadily increased. Every passing week, I got a tad more comfortable with the car driving me. Now, I have had FSD log 75% of my 13,000 miles since v14. I barely drive my car manually, and that’s exactly how I like it.

My Tesla has changed the way I drive and how I choose to travel.

In the past, I was always one of those anxious drivers, overly concerned about the parking situation, never wanting to drive in cities, and avoiding anything that made me a little uncomfortable when on the road. FSD has changed that completely.

It has made traveling fun, driving less stressful, and parking a non-issue. I truly love this car and what it has done for me and my driving anxiety.

Maintenance and Cost Savings

A buddy of mine who took delivery of a Model Y right after me, also his first EV, texted me yesterday and said, “When do I take this thing for service? I don’t even know what it needs.”

This year I have spent $67.41 on service for my car:

  • Free Front Camera Housing Cleaning
  • $65 for a Tire Rotation at home from Tesla (easily avoidable if I just would have gone to a tire place or did it myself, but it was less than 20 degrees outside and the Service Tech did it at 7 am while I was asleep)
  • $2.41 on a jug of Windshield Washer Fluid at Sheetz with my reward points

No spark plugs, no oil changes, no anything. Combine it with what you save on charging at home, and my ownership experience overall has been relatively cheap. I pay no more than I did for my Bronco for the car payment (around $400 per month), and my insurance went up about $60, but within the first four months I was given a safe driving discount by my agent. This brought it to about a $40 increase.

Now let’s factor in what I’ve saved in gas for the year:

According to my Charge Stats in the Tesla App, I’ve saved $836 over the course of the year by driving a Tesla over an ICE vehicle. If you look at the graph, you’ll notice my Supercharger utilization dropped significantly in April, which makes sense.

This is when I started charging at home. Those savings would likely be closer to $1,500 if I had been charging at home all along.

Real-World Range

I never reset any Trip on my Tesla when I bought it, so all of these efficiency stats are for the life of the vehicle thus far through 16,063 miles.

My Tesla has a lifetime average of 260.1 Wh/mi (watt-hours per mile), which equates to 3.84 mi/kWh (miles per kilowatt-hour). This is pretty average, and I know I could be more efficient, but I use climate control liberally (it’s always on, even if the windows are down), and I love to let FSD drive me around in Hurry Mode.

Even when I’m driving manually, it’s because I’m on a dry, windy road and I want to take advantage of the awesome suspension and damping that the Model offers. Driving that car on a back road with some twists is one of the most fun things to do.

To achieve really excellent range and efficiency ratings, you really have to be more conservative with some things, and those are sacrifices I’m personally not willing to make. I want the A/C or Heat on, and I occasionally will increase drag by driving with the windows down.

I prefer Hurry mode on FSD, and I’m willing to sacrifice a few miles of range for that certain style of driving.

Interior, Visibility, Accessories, and More

My Favorite Interior Ever

The Model Y interior, like every Tesla interior, is not for everyone. Personally, I was never a fan of the minimalistic approach prior to ownership. As ridiculous as it is, I liked a simple knob for adjusting the temperature and fan speed. Even so, to this day, it takes me longer to pull up the climate settings to adjust things in my Tesla than it ever did in cars with a million knobs and buttons.

I can’t tell you how many times my finger has missed the On/Off button on the climate screen in the Model Y because of dips, bumps, turns, and just normal movement during operation. Do I like the way things are controlled in my Tesla? Yes, of course. Plus, Grok is so integrated into the car now that I could truly never have to touch the screen again for anything other than starting Self-Driving.

However, I still find that there are valid arguments for people who like knobs and buttons. As ugly as it might be to me now, I think it is a tad more intuitive because it’s much harder to miss and much easier to make a quick adjustment than with a touchscreen.

With that being said, the touchscreen is great. It is so responsive and is as good as using an iPhone. There is no delay like most automotive touchscreens, where it feels sort of clunky for 2026.

I love to watch TV and Movies or YouTube on it when I’m parked anywhere. My Fiancèe and I have made it a date night several times over the past year: we’ll pick a spot to eat, get it to go, and enjoy it in the car while watching something. It’s great in the Fall when the leaves are turning orange.

The interior is, overall, a great part of the car. It’s very easy to keep clean, and when it’s clean, it truly feels like you’re in a spacecraft. It is one of the coolest interiors out there, maybe not as luxurious as some high-end Mercedes-Benz or BMW models, but it has a clean and simple feel that is better than many cars in its weight class.

I will say I do miss the Textile seats of the Model Y Standard, but I do not miss them when I am hot. I would still take the Vegan Leather because of the ventilated seats.

Rear Window Visibility is Pointless

If you like a rear windshield, just be aware of the fact that the Model Y basically does not have one. It almost feels pointless to be there, and the Model Y L has something that is much more “standard” in terms of rear windshields in a crossover/SUV:

It doesn’t mean much to me because the rear camera is great. However, I have found myself just annoyed with the fact that it’s even there to begin with.

Accessories I Bought

I went for 3D MaxPider car mats throughout, some center console storage, trunk storage, and matching window tint on the front windows. I also bought Tesla’s Pet Liner, which is great because it comes with door coverage and a bit of a barrier. My pup, Finn, climbs right over it and prefers the front seat, so I fold it in half, and it still covers the passenger seat very well:

They’re all pretty standard accessories, but the one thing I use the most is actually this phone mount from Amazon.

It’s great for making FSD content for TikTok or throwing my phone on it just to hold. I never use it to watch anything (I’m wildly against that concept), and I usually use the wireless charging mat that comes standard. It is really great and convenient, and the magnet is super strong.

Cabin Noise, Sound System Quality

The Model Y Premium comes with acoustic-lined glass, which really dampens a lot of the road noise. My car has one of the quieter cabins I’ve ever been in. I can still remember my 2008 Escape Hybrid and how loud it was in there; I thought my Tesla would be that way, but boy was I wrong.

It is such a peaceful ride that even sitting at stoplights behind loud, obnoxious Hondas with shopping cart handles as spoilers does not bother me. A buddy of mine in a 2021 Model Y said upon his first ride in my car that it was a “night and day” difference between the two.

As far as the sound system goes, two of the more outgoing people in my life who love loud music and concerts recently said to me that “the Tesla is quite a time” because of how immersive the listening experience is. The bass is excellent; the ambient lighting truly rounds out the experience.

Even my Dad, who is somewhat of a speaker snob (I can remember going to Tweeter as a boy with him to look at receivers, and he’s always had massive speakers in the house for cranking up some music) has commented on how good the sound quality is. I remember when I bought a Honda Civic a few years ago- his first ride in it- he said, “Damn, the speakers in here suck.”

He wasn’t wrong. They were awful. But in the Tesla, they’re damn good.

Should you buy a Model Y?

Look, I will recommend this car to anyone who asks. I tell my friends constantly that I love my Model Y so much, especially because it just gets better and better over time.

But I also understand the skepticism. I’ll admit one of the most disappointing things about this car is how much range I lose in the winter. In a 40-mile round-trip drive to get wings with some friends in January, I lost 120 miles of range. This is something that would not deter me from buying this car, but at the time, I also didn’t have home charging. Ownership, at that point, was a bit of a pain in the butt.

The thing is, to me, it’s still better than driving a gas car. I just have more fun in a Tesla.

A friend of mine recently bought a new car, and she said she went with a Chevy Equinox because it was a larger vehicle and she has a child. I told her, “I don’t think I’ll ever buy anything other than a Tesla. Once you go Tesla, you never go back.”

“I cannot afford a Tesla,” she said. We all know the ridiculous narrative around Tesla pricing by now, and after she found out how much I pay for my car and the fact that it has the IIHS Top Safety Pick+ rating, she admitted she probably would have done the same if she had known. I wish she would have asked.

The only car I would take over mine is the Cybertruck. And right now, I just can’t afford a Cybertruck, so I’ll stick with the Model Y. I am so satisfied with my pick, and I would buy this car time and time again.

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Elon Musk

Elon Musk rips ABC News over fatal NYC Tesla crash report

Musk pushed back on NYC Tesla crash coverage, pointing to a pattern of premature blame.

Published

1 day ago

on

September 9, 2026

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Elon Musk pushed back overnight against media framing of a fatal Tesla crash in Midtown Manhattan, telling a user on X that “it wasn’t the car” and that the vehicle’s Autopilot system had nothing to do with the wreck.

The crash happened just before 3 a.m. Wednesday, when a 2024 Tesla Model Y struck a sidewalk shed outside 315 Madison Ave., a bus stop pole and a mailbox on East 42nd Street, according to the NYPD. The car kept moving several more blocks before stopping near Second Avenue. Both women inside, each 27, were taken to Bellevue Hospital, where the passenger was pronounced dead. The driver was charged with vehicular manslaughter, driving while ability impaired and leaving the scene of an accident.

Police have not attributed the crash to Autopilot or Full Self-Driving in any public statement. The charges point to impairment, not software. Musk’s response followed a since-deleted ABC News post that he said mischaracterized the incident. Replying to a user on X, Musk wrote that if Autopilot had been engaged, “they would not have crashed,” and added that “the legacy media will never forgive Tesla for failing to advertise with them,”

It’s a familiar cycle for Tesla. In June, headlines from several national outlets described a fatal crash in Katy, Texas, as happening while the car was “on autopilot,” based on the driver’s own account to police after his Model 3 struck a home and killed a 76-year-old woman. Tesla’s data told a different story when Ashok Elluswamy, Tesla’s head of AI, said the driver had pressed the accelerator to 100% and reached 73 mph in a residential zone. Harris County prosecutors later confirmed the human override and the driver was charged with manslaughter.

Florida Gov. Ron DeSantis pointed to that same Katy crash last month to argue that outlets routinely name Tesla in crash headlines while leaving other automakers unnamed, even after a driver’s own actions are shown to be the cause. A similar pattern played out in 2024, when Musk had to clarify that FSD was never even downloaded onto the Model 3 involved in a fatal Colorado DUI crash, despite a passenger’s claim that an “auto drive feature” was in use.

Tesla has not issued a separate statement on the Manhattan crash beyond Musk’s posts on X. The NYPD’s investigation is ongoing, and no cause for the driver losing control has been released.

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