News
Elon Musk’s SpaceX AMA: Living on Mars, Spaceship Info, Timeline
SpaceX CEO Elon Musk hosted a Reddit AMA (Ask Me Anything) earlier this afternoon and spent several hours drinking whiskey, trolling the audience, answering some great questions, and generally having a blast. He revealed a vast array of fascinating new details about SpaceX’s giant new rocket (BFR), its upper stage spaceship (BFS), and much more.
All of Musk’s answers from the AMA have been collated and organized by category below. You’ll want to shy away from the AMA page itself, currently clocking in at more 10,000 comments.
When useful, particularly dense and technical responses have been summarized in italics for a broader audience.
Living on Mars
Q: Obviously there will be an extreme amount of care put into what is sent on the first missions, and the obvious answer of “Solar Panels” and “Fuel Production Equipment” is included, but what else?
A (Elon): Our goal is get you there and ensure the basic infrastructure for propellant production and survival is in place. A rough analogy is that we are trying to build the equivalent of the transcontinental railway. A vast amount of industry will need to be built on Mars by many other companies and millions of people.
Q: Does your Mars city feature permanently anchored BFS spaceships?
A (Elon): Wouldn’t read too much into that illustration
The aforementioned Martian city. Spaceships can be seen near the center. (SpaceX)
Q: Have any candidate landing sites for the Mars base been identified?
A (Elon): Landing site needs to be low altitude to maximize aero braking, be close to ice for propellant production and not have giant boulders. Closer to the equator is better too for solar power production and not freezing your ass off.
Q: Who will design and build the ISRU system for the propellant depot, and how far along is it?
A (Elon): SpaceX. Design is pretty far along. It’s a key part of the whole system.
Without ISRU (In-Situ Resource Utilization), BFS is unlikely to ever be able to take humans to Mars affordably enough to enable large colonies. This news is thus of huge importance, and suggests that SpaceX will be able to focus on developing BFR and BFS near-term.
Another hypothetical SpaceX city on Mars. Bases will need to be located near water resources. (SpaceX)
SpaceX Big F** Spaceship (BFS)
Q: Will the BFS landing propellants have to be actively cooled on the long trip to Mars?
A (Elon): The main tanks will be vented to vacuum, the outside of the ship is well insulated (primarily for reentry heating) and the nose of the ship will be pointed mostly towards the sun, so very little heat is expected to reach the header tanks. That said, the propellant can be cooled either with a small amount of evaporation. Down the road, we might add a cryocooler.
A (Elon): exactly (while methane could be kept in its liquid form solely through high pressure storage, the pressures required are immense and would require tanks that would be far too heavy for a rocket’s second stage.
Cold liquid oxygen and methane will unavoidably warm up over time, eventually returning to their gaseous forms if allowed. SpaceX’s solution for BFS, which will spend several months between Earth and Mars, is to rely on the Ship’s already great insulation, as well as minimal evaporative cooling (similar to how swamp coolers work).
Q: Will the BFS heat shield be mounted on the skin, or embedded?
A (Elon): The heat shield plates will be mounted directly to the primary tank wall. That’s the most mass efficient way to go. Don’t want to build a box in box.
Dragon 2’s PICA-X heat shield can be seen on the right. BFS’s heat shield will be made of the same material, albeit on a much larger scale. (SpaceX)
Q: Can the BFS delta wings and heat shield be removed for deep space missions?
A (Elon): Wouldn’t call what BFS has a delta wing. It is quite small (and light) relative to the rest of the vehicle and is never actually used to generate lift in the way that an aircraft wing is used.
Its true purpose is to “balance out” the ship, ensuring that it doesn’t enter engines first from orbit (that would be really bad), and provide pitch and yaw control during reentry.
Q: Why is the 2017 BFS spaceship largely cylindrical?
A (Elon): Best mass ratio is achieved by not building a box in a box. The propellant tanks need to be cylindrical to be remotely mass efficient and they have to carry ascent load, so lowest mass solution is just to mount the heat shield plates directly to the tank wall.
For a rocket, mass ratio refers to its weight with a full load of propellant divided by its weight while completely empty. The lighter a rocket’s structure, the more mass it can lift into a given orbit.
-
- SpaceX’s conceptual Interplanetary Transport System from 2016 was considerably larger and more structurally complex than 2017’s BFR. (SpaceX)
-
- The relatively cylindrical BFS reduces complexity and lowers weight. (SpaceX)
Q: How does the BFS achieve vertical stabilization, without a tail?
A (Elon): Tails are lame
A (Elon): +1 (The space shuttle’s vertical stabilizer was completely useless for most of the reentry profile, as it was in complete aerodynamic shadow. I think it’s clear a craft doesn’t need one for reentry, only for subsonic gliding, which BFS doesn’t really do.)
BFS doesn’t need a tail because tails add weight, are of little use during orbital reentry, and BFS is not intended to glide.
Q: Why was the number of BFS landing legs increased from 3 to 4?
A (Elon): Because 4
A (Elon): Improves stability in rough terrain
Q: How is the radiation shielding in the ITS?
A (Elon): Ambient radiation damage is not significant for our transit times. Just need a solar storm shelter, which is a small part of the ship. Buzz Aldrin is 87.
While radiation fearmongers may balk at this statement, it is to some extent true. The risks from radiation (PDF) for a six month journey in deep space are approximately similar to several dozen CT scans, while two years spent on the surface of Mars with little to no shielding would result in about the same amount of exposure. Underground habitats could alleviate a considerable amount of the risk from living on Mars’ surface.
The issues and dangers posed by radiation ought not be trivialized but they can be dealt with, particularly if BFR can deliver massive payloads to the planet.
Q: Why was the location and shape of the BFS header/landing tanks changed?
A (Elon): The aspiration by the change was to avoid/minimize plumbing hell, but we don’t super love the current header tank/plumbing design. Further refinement is likely.
Header tanks refer to smaller tanks contained within the main propellant tanks that are used to ignite engines in microgravity. It’s easier to pressurize or simply fill the smaller tanks than it is to do so with the massive main tanks.
BFS’ header tanks circled in red. (SpaceX)
BFS Tanker
Q: Will the BFS tanker’s payload section be empty, or include extra propellant tanks?
A (Elon): At first, the tanker will just be a ship with no payload. Down the road, we will build a dedicated tanker that will have an extremely high full to empty mass ratio (warning: it will look kinda weird).
Using one version of the BFS as both a tanker and ship will streamline the initial development process for the rocket.
Two Spaceships docked for refuelling. (SpaceX)
Q: Will the BFS tanker ships (have to) do a hoverslam landing?
A (Elon): Landing will not be a hoverslam, depending on what you mean by the “slam” part. Thrust to weight of 1.3 will feel quite gentle. The tanker will only feel the 0.3 part, as gravity cancels out the 1. Launch is also around 1.3 T/W, so it will look pretty much like a launch in reverse….
BFS will land relatively gently, and BFR’s liftoff will also be gentle.
Development schedule
Q: With the first two cargo missions scheduled to land on Mars in 2022, what kind of development progress can we expect to see from SpaceX in the next 5 or so years leading up to the maiden flight?
Will we see BFS hops or smaller test vehicles similar to Grasshopper/F9R-Dev? Facilities being built? Propellant plant testing? etc. etc.
A (Elon): A lot. Yes, yes, and yes.
A (Elon): Will be starting with a full-scale Ship doing short hops of a few hundred kilometers altitude and lateral distance. Those are fairly easy on the vehicle, as no heat shield is needed, we can have a large amount of reserve propellant and don’t need the high area ratio, deep space Raptor engines.
Next step will be doing orbital velocity Ship flights, which will need all of the above. Worth noting that BFS is capable of reaching orbit by itself with low payload, but having the BF Booster increases payload by more than an order of magnitude. Earth is the wrong planet for single stage to orbit. No problemo on Mars.
The first real tests of the BFR will be done by hopping a full-scale BFS “several hundred kilometers”. BFS is capable of launching itself and a tiny payload into orbit, but the utility is limited on Earth. On Mars, BFS will be far more capable as a single stage to orbit (SSTO) launch vehicle.
-
- F9R-dev, used to test vertical take off and landing for Falcon 9. BFR will go through a similar program with its spaceship upper stage prior to orbital missions. (Steve Jurvetson)
-
- F9R sadly suffered a software bug and self-destructed in 2014, but SpaceX had already learned most of what it needed to begin Falcon 9 recoveries. (Steve Jurvetson)
Raptor and rocket propulsion
Q: Why was Raptor thrust reduced from ~300 tons-force to ~170 tons-force?
A (Elon): We chickened out. The engine thrust dropped roughly in proportion to the vehicle mass reduction from the first IAC talk. In order to be able to land the BF Ship with an engine failure at the worst possible moment, you have to have multiple engines. The difficulty of deep throttling an engine increases in a non-linear way, so 2:1 is fairly easy, but a deep 5:1 is very hard. Granularity is also a big factor. If you just have two engines that do everything, the engine complexity is much higher and, if one fails, you’ve lost half your power. Btw, we modified the BFS design since IAC to add a third medium area ratio Raptor engine partly for that reason (lose only 1/3 thrust in engine out) and allow landings with higher payload mass for the Earth to Earth transport function.
The Raptor engine’s maximum thrust has been decreased mainly because the size of the rocket decreased, from 12m to 9m in diameter. For redundancy’s sake, SpaceX has added a third central engine to the spaceship, versus the two engines mentioned at the 2017 IAC.
BFS’ delta “wings” from the rear of the ship. Also shown are the Raptors, with the two in the center now reportedly expanded to three engines. (SpaceX)
Q: Will the BFR autogenous pressurization system be heat exchanger based?
A (Elon): We plan to use the Incendio spell from Harry Potter
A (Elon): But, yes and probably
Autogenous pressurization refers to the method of propellant tank pressurization used. In microgravity conditions, tanks must be pressurized to keep fuel flowing to the engines and to improve the density of the fuel. While Falcon 9 currently uses high-pressure helium, ITS and now BFR have been designed to use the actual propellant in their tanks (methane and oxygen) for pressurization. This reduces the number of failure modes on BFR and improves the spaceship’s payload capabilities.
Q: Will the BFS methalox control thrusters be derived from Raptor or from SuperDraco engines?
A (Elon): The control thrusters will be closer in design to the Raptor main chamber than SuperDraco and will be pressure-fed to enable lowest possible impulse bit (no turbopump spin delay).
Like Falcon 9, BFR will need gas thrusters (RCS, reaction control system) to control its orientation (and refuel) while in microgravity conditions. While Falcon uses cold nitrogen gas thrusters, BFR will utilize the propellant it is already carrying for Raptor, methane and oxygen. Again, the goal of this is to reduce complexity.
Q: Could you update us on the status of scaling up the Raptor prototype to the final size?
A (Elon): Thrust scaling is the easy part. Very simple to scale the dev Raptor to 170 tons.
The flight engine design is much lighter and tighter, and is extremely focused on reliability. The objective is to meet or exceed passenger airline levels of safety. If our engine is even close to a jet engine in reliability, has a flak shield to protect against a rapid unscheduled disassembly and we have more engines than the typical two of most airliners, then exceeding airline safety should be possible.
That will be especially important for point to point journeys on Earth. The advantage of getting somewhere in 30 mins by rocket instead of 15 hours by plane will be negatively affected if “but also, you might die” is on the ticket.
SpaceX’s subscale Raptor, the one seen in videos and photos of it firing, is understood to be a bit more than half the size of the operational engine described at IAC 2017. Increasing the scale of the engine is not the difficult aspect of development. Rather, optimization, weight reduction, and extreme reusability are the main sources of difficulty needed before Raptor is flight-ready. This reusability is central to the goal of reliable and rapid reuse of orbital-class rockets.
-
- SpaceX revealed this stunning photo of Raptor’s first (partial) hot-fire test the night before Musk’s talk at Guadalajara. (SpaceX)
-
- SpaceX’s subscale Raptor engine has completed more than 1200 seconds of testing in less than two years. (SpaceX)
Q: Can BFS vacuum-Raptors be fired at sea level pressure?
A: The “vacuum” or high area ratio Raptors can operate at full thrust at sea level. Not recommended.
Put simply, vacuum nozzles do not like to operate in an atmosphere.
Mars communications
Q: Does SpaceX have any interest in putting more satellites in orbit around Mars (or even rockets) for internet/communications before we get feet on the ground? Or are the current 5-6 active ones we have there sufficient?
A (Elon): Yes
Q: Also will there be some form of an internet or communications link with Earth? Is SpaceX going to be in charge of putting this in or are you contracting some other companies?
A (Elon): If anyone wants to build a high bandwidth comm link to Mars, please do.
Taken side by side, this likely indicates that SpaceX will develop a high-bandwidth Mars-Earth communications link if nobody else does, but that they would logical prefer that someone else builds that infrastructure beforehand.
Q: The concept of an internet connection on Mars is kinda awesome. You could theoretically make an internet protocol that would mirror a subset of the internet near Mars. A user would need to queue up the parts of the internet they wanted available and the servers would sync the relevant data.
A (Elon): Nerd
A (Elon): But, yes, it would make sense to strip the headers out and do a UDP-style feed with extreme compression and a CRC check to confirm the packet is good, then do a batch resend of the CRC-failed packets. Something like that. Earth to Mars is over 22 light-minutes at max distance.
A (Elon): 3 light-minutes at closest distance. So you could Snapchat, I suppose. If that’s a thing in the future.
The communication delay between Earth and Mars (at least several minutes one-way) will prevent any Martian habitats from simply integrating with Earth’s Internet. The delay will require some sort of mediation. As an example, a user on Mars could select the websites they want to browse or videos they want to watch beforehand, and they would be available between several minutes and an hour later.
SpaceX’s Starlink satellite constellation efforts could provide the company with valuable experience that can be applied around Mars. (unofficial logo by Eric Ralph)
Boring!
Q: Boring question about Mars:
A (Elon): More boring!
Miscellaneous silliness
Q: This is one bizarre AMA so far…
A (Elon): Just wait…
Q: i feel like thats a threat. “just wait. it will get way more bizarre than that. let me finish my whiskey”
A (Elon): How did you know? I am actually drinking whiskey right now. Really.
…No comment…
All things considered, this was a wildly successful AMA. Elon clearly had a whole lot of fun, the audience got lightheartedly trolled, and SpaceX fans will undoubtedly be chewing over the technical details he elucidated for weeks to come. Special thanks are owed to the subreddit /r/SpaceX and user /u/_Rocket_, who together managed to flood the AMA with an array of intelligent, pointed, and reasonable questions, at least ten of which were answered by Musk.
News
SpaceX’s Starfall just went from secret to storefront
SpaceX now pitches Starfall missions with 1,000 kg payloads, weeks of microgravity, and Starlink connectivity.
SpaceX has put up a dedicated commercial page for Starfall, its disk shaped reentry capsule, laying out for the first time what customers actually get when they book a flight. The page, live at spacex.com/starfall, pitches “affordable, routine access to microgravity” and invites companies to get in touch about flying manufacturing, research or testing payloads.
The specs are short and specific. Each Starfall mission carries up to 1,000 kg of payload, supplies 1 kW of power and connects through an Ethernet interface. Mission length is tailored to the customer, and the payload stays online the entire time through Starlink, which means researchers can pull data from an experiment while it is still in orbit instead of waiting for splashdown.
SpaceX is launching a secret spacecraft that could change how things are made in space
SpaceX is aiming the service at three markets. Biomedical customers are told they can grow stem cell organoids, replacement tissue and layered biomaterials. Pharmaceutical companies are pitched on protein and small molecule drug crystals, which form smaller and more uniform shapes without gravity driven convection. Materials science rounds out the list, with semiconductors and other next generation materials grown in vacuum and microgravity.
The page also makes clear which rocket SpaceX is counting on. “By launching on Starship, Starfall brings a reliable and scalable cadence previously unavailable to the market,” the company wrote, contrasting weeks of continuous microgravity with the seconds offered by drop towers and parabolic flights. No price or first operational flight date is listed.
The commercial push is a sharp turn from how Starfall started. SpaceX said almost nothing about the capsule ahead of its first flight in June, and nearly everything known came from FAA and FCC filings describing a disk about 10.2 feet wide and 2.5 feet tall that can return 2,200 pounds of cargo. By its second flight on the Bandwagon-5 rideshare in October, Starfall was listed by name on the mission page, though SpaceX still did not say what it carried.
Customers appear to be lining up. SpaceX said in its third quarter results that it signed three commercial Starfall missions during the quarter. On the earnings call, President Gwynne Shotwell described the capsule as providing “routine relatively low cost access to microgravity environments for scientific research, including improving our understanding of diseases like cancer and diabetes,” and said the three new missions would fly on Starship.
The branding effort extends past the website. SpaceX added a Starfall T-shirt to its online store on Monday as part of a batch of new merchandise, giving the program a place next to Starship, Starlink and Starshield in the company’s lineup.
The move also puts SpaceX in more direct competition with companies it launches. Varda Space Industries, which has built much of the in-space manufacturing market so far, flew its W-Series 7 capsule on the same Bandwagon-5 mission as Starfall in October. Varda’s capsules are roughly three times smaller than Starfall, and SpaceX controls the ride to orbit for both.
Starfall’s near term cadence depends on Starship. SpaceX is preparing for Flight 15 after completing static fires of Ship 42 and its Super Heavy booster in late October, and is aiming to catch both stages with the launch tower on that flight.
Elon Musk said weeks ago during SpaceX’s third-quarter earnings call that the company’s Grok Bot, its autonomous AI Agent platform, was showing “the fastest growth of a product” that he’d ever seen in his life.
Now, SpaceXSI is scaling back Grok Bot users’ weekly limits, much to the surprise of those who have relied on it to take away monotonous tasks in their lives.
Elon Musk’s terse November 1 reply on X captured a sharp tension in the early days of agentic AI. Responding to a user who asked for a Grok Bot usage reset after hitting 100 percent with four days still left on the weekly cycle, Musk wrote: “The cost of serving Grok Bot was unsustainably high relative to revenue.”
@DogecoinNorway The cost of serving Grok Bot was unsustainably high relative to revenue
— Elon Musk (@elonmusk) November 1, 2026
The post arrived amid a wave of similar complaints from paying subscribers whose meters had jumped unexpectedly toward or to the limit, sometimes overnight and with little corresponding activity. It also stood in clear contrast to statements Musk had made only days and weeks earlier.
On the SpaceX third-quarter earnings call in mid-to-late October, Musk had described Grok Bot in almost the opposite terms. He called it “the fastest growth of a product that I’ve ever seen in my life” and said he had “never seen anything grow this fast.”
Company figures put paid weekly users at roughly 800,000 earlier in the month, more than doubling over the prior period. Daily active users had climbed from under 100,000 in early September to over 600,000 by late October.
Musk emphasized that the product has no free tier and that users appear to be getting real value beyond what they pay. In other remarks, he noted that usage per user was rising rather than declining, the opposite of the usual decay pattern for new software.
Grok Bot, launched around August, functions as an always-available agent with its own persistent cloud computer; it can schedule, research, shop, browse, and execute multi-step workflows even after the user steps away. Access is bundled into X subscription tiers (roughly $30, $100, and $200 per month) and certain Cursor plans, drawing from shared weekly usage pools whose exact sizes have not been publicly detailed.
The economics of that model are what Musk’s November 1 post put in the spotlight. Agentic systems burn far more compute than ordinary chatbot exchanges. Each task can trigger repeated model calls, tool use, web actions, and sustained background work.
When growth is as rapid as Musk celebrated, the absolute compute bill scales quickly even if average revenue per user stays fixed under flat monthly subscriptions. Industry observers noted the opportunity cost as well: the same GPUs can be rented to other AI labs at higher rates.
A simple back-of-the-envelope comparison circulating after the post illustrated the gap: if every reported daily user paid the top tier, annualized subscription revenue would still be modest relative to the scale of compute infrastructure SpaceX is building and leasing to companies like Anthropic.
Some users also reported possible dashboard anomalies around the same period, though Musk’s framing treated the underlying cost-revenue imbalance as the core issue rather than a pure metering glitch.
The juxtaposition is the core of this exchange. Within roughly two weeks of publicly framing Grok Bot as an unprecedented success with strong unit economics and no free tier, Musk acknowledged that serving the same product had become unsustainable relative to the revenue it generates.
For the broader industry, the episode underscores a structural challenge of the agent era: demand is real and growing faster than many expected, yet the cost of fulfilling that demand through always-on, multi-step agents can outrun subscription pricing before companies can adjust limits, introduce metered billing, or raise prices.
Musk’s reply did not promise an immediate reset or higher allowances; it simply stated the constraint. In doing so, it supplied a rare, explicit public data point on the unit economics of a high-profile AI agent just as adoption numbers were still being celebrated as the fastest in Musk’s experience.
The tension between rapid, paid growth and the compute required to deliver it is now on the record.
News
Tesla owners who tap Emergency Drive Away for fun are in for a surprise
Tapping Activate on Tesla’s Emergency Drive Away reportedly triggers a $539 service bill without moving.
Tesla owners who press Activate on Emergency Drive Away may be on the hook for a service bill even if their car never leaves the Supercharger stall.
Yaro, who posts about Tesla service cases on X as @Tutrifour, said a customer called after tapping Activate while still plugged into a Supercharger. The owner was about to pull away, remembered the cable was still connected and stopped. The car never moved, but the touchscreen showed a red alert reading “Emergency Drive Away has been activated” with “Service is required” underneath. A Service Mode screenshot showed the active alert BMS_a228_EmergencyDriveAwayServiceRequired, which Yaro said only Tesla Service can clear.
Here is a lesson to Tesla owners. Don’t press Activate on the new Emergency Drive Away feature on your Tesla because service charges $539 to inspect the charge port and to clear the alert. Yes, even if you didn’t move the car an inch. https://t.co/NZJENw4SQv
— Yaro (@Tutrifour) October 30, 2026
The cost of clearing it was the bigger surprise. “Don’t press Activate on the new Emergency Drive Away feature on your Tesla because service charges $539 to inspect the charge port and to clear the alert. Yes, even if you didn’t move the car an inch,” Yaro wrote. The $539 figure comes from that single case, and Tesla has not published a set price for the inspection or commented on the post. Yaro also noted that the car would still charge with the alert on screen.
Tesla launched Emergency Drive Away on October 1 with software update 2026.38.3, letting drivers pull away from a U.S. Supercharger with the cable still attached, as Teslarati reported. To use it, a driver shifts into Drive while connected, holds the brake and taps Activate. The prompt warns that driving with the cable connected will damage the vehicle and the Supercharger, and that short camera recordings will be shared with Tesla.
Tesla Charging has been clear about what follows a real activation. Repairs to a Supercharger stall can run up to $25,000 depending on the site, a service visit for the car’s charge port is mandatory, and deliberate misuse “will invoke additional penalties.” What the company had not spelled out is that the service requirement is triggered the moment Activate is pressed, not the moment the cable breaks away.
From an engineering standpoint, that is the cautious choice. Once Activate is pressed, the car cannot be sure the charge port latch was not stressed, so flagging it for inspection removes the guesswork. It also means the button carries a price on its own, which is a stronger deterrent against casual use than any warning screen.
Customer called because they have an active alert after tapping ACTIVATE on the new Emergency Drive Away feature. They didn’t actually drive away but were about to until they “remembered” they had the charge cable connected.
This alert can only be cleared by Tesla Service. https://t.co/SkHyJJPFwU
— Yaro (@Tutrifour) October 28, 2026
The report follows the feature’s first known real world use, when a driver in Austin during F1 weekend appeared to trigger it by accident and dragged the Supercharger cable along with the car. The Reddit user who filmed it said the driver seemed to have only half read the prompts.
For owners, the takeaway is to treat the red prompt as a stop sign. If it appears after shifting out of Park by mistake, shift back and unplug the normal way from the touchscreen, the Tesla app or the button on the charge handle. Activate is meant for moments when staying at the stall is the bigger risk, and Tesla is now pricing it that way.
SpaceX’s Starfall just went from secret to storefront
Grok Bot users hit with weekly limits early, Elon Musk explains what happened
