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.
Tesla executive Lars Moravy appeared today in front of the U.S. Senate Commerce Committee to highlight the importance of modernizing autonomy standards by establishing a federal framework that would reward innovation and keep the country on pace with foreign rivals.
Moravy, who is Tesla’s Vice President of Vehicle Engineering, strongly advocated for Congress to enact a national framework for autonomous vehicle development and deployment, replacing the current patchwork of state-by-state rules.
These rules have slowed progress and kept companies fighting tooth-and-nail with local legislators to operate self-driving projects in controlled areas.
Tesla already has a complete Robotaxi model, and it doesn’t depend on passenger count
Moravy said the new federal framework was essential for the U.S. to “maintain its position in global technological development and grow its advanced manufacturing capabilities.
He also said in a warning to the committee that outdated regulations and approval processes would “inhibit the industry’s ability to innovate,” which could potentially lead to falling behind China.
Being part of the company leading the charge in terms of autonomous vehicle development in the U.S., Moravy highlighted Tesla’s prowess through the development of the Full Self-Driving platform. Tesla vehicles with FSD engaged average 5.1 million miles before a major collision, which outpaces that of the human driver average of roughly 699,000 miles.
Moravy also highlighted the widely cited NHTSA statistic that states that roughly 94 percent of crashes stem from human error, positioning autonomous vehicles as a path to dramatically reduce fatalities and injuries.
🚨 Tesla VP of Vehicle Engineering, Lars Moravy, appeared today before the U.S. Senate Commerce Committee to discuss the importance of outlining an efficient framework for autonomous vehicles:
— TESLARATI (@Teslarati) February 4, 2026
Skeptics sometimes point to cybersecurity concerns within self-driving vehicles, which was something that was highlighted during the Senate Commerce Committee hearing, but Moravy said, “No one has ever been able to take over control of our vehicles.”
This level of security is thanks to a core-embedded central layer, which is inaccessible from external connections. Additionally, Tesla utilizes a dual cryptographic signature from two separate individuals, keeping security high.
Moravy also dove into Tesla’s commitment to inclusive mobility by stating, “We are committed with our future products and Robotaxis to provide accessible transportation to everyone.” This has been a major point of optimism for AVs because it could help the disabled, physically incapable, the elderly, and the blind have consistent transportation.
Overall, Moravy’s testimony blended urgency about geopolitical competition, especially China, with concrete safety statistics and a vision of the advantages autonomy could bring for everyone, not only in the U.S., but around the world, as well.
Tesla launched a new configuration of the Model Y this week, bringing more complexity to its lineup of the vehicle and adding a new, lower entry point for those who require an All-Wheel-Drive car.
However, the broadening of the Model Y lineup in the United States could signal a somewhat uncomfortable reality for Tesla fans and car buyers, who have been vocal about their desire for a larger, full-size SUV.
Tesla has essentially moved in the opposite direction through its closure of the Model X and its continuing expansion of a vehicle that fits the bill for many, but not all.
Tesla brings closure to Model Y moniker with launch of new trim level
While CEO Elon Musk has said that there is the potential for the Model Y L, a longer wheelbase configuration of the vehicle, to enter the U.S. market late this year, it is not a guarantee.
Instead, Tesla has prioritized the need to develop vehicles and trim levels that cater to the future rollout of the Robotaxi ride-hailing service and a fully autonomous future.
But the company could be missing out on a massive opportunity, as SUVs are a widely popular body style in the U.S., especially for families, as the tighter confines of compact SUVs do not support the needs of a large family.
Although there are other companies out there that manufacture this body style, many are interested in sticking with Tesla because of the excellent self-driving platform, expansive charging infrastructure, and software performance the vehicles offer.
Additionally, the lack of variety from an aesthetic and feature standpoint has caused a bit of monotony throughout the Model Y lineup. Although Premium options are available, those three configurations only differ in terms of range and performance, at least for the most part, and the differences are not substantial.
Minor Expansions of the Model Y Fail to Address Family Needs for Space
Offering similar trim levels with slight differences to cater to each consumer’s needs is important. However, these vehicles keep a constant: cargo space and seating capacity.
Larger families need something that would compete with vehicles like the Chevrolet Tahoe, Ford Expedition, or Cadillac Escalade, and while the Model X was its largest offering, that is going away.
Tesla could fix this issue partially with the rollout of the Model Y L in the U.S., but only if it plans to continue offering various Model Y vehicles and expanding on its offerings with that car specifically. There have been hints toward a Cyber-inspired SUV in the past, but those hints do not seem to be a drastic focus of the company, given its autonomy mission.
Model Y Expansion Doesn’t Boost Performance, Value, or Space
You can throw all the different badges, powertrains, and range ratings on the same vehicle, it does not mean it’s going to sell better. The Model Y was already the best-selling vehicle in the world on several occasions. Adding more configurations seems to be milking it.
The true need of people, especially now that the Model X is going away, is going to be space. What vehicle fits the bill of a growing family, or one that has already outgrown the Model Y?
Not Expanding the Lineup with a New Vehicle Could Be a Missed Opportunity
The U.S. is the world’s largest market for three-row SUVs, yet Tesla’s focus on tweaking the existing Model Y ignores this. This could potentially result in the Osborne Effect, as sales of current models without capturing new customers who need more seating and versatility.
Expansions of the current Model Y offerings risk adding production complexity without addressing core demands, and given that the Model Y L is already being produced in China, it seems like it would be a reasonable decision to build a similar line in Texas.
Listening to consumers means introducing either the Model Y L here, or bringing a new, modern design to the lineup in the form of a full-size SUV.
Elon Musk
Elon Musk reiterates Tesla Optimus’ most sci-fi potential yet
Musk shared his comments in a series of posts on social media platform X.
Elon Musk recently reiterated one of the most ambitious forecasts for Tesla’s humanoid robot, Optimus, stating it could become the first real-world example of a Von Neumann machine. He also noted once more that Optimus would be Tesla’s biggest product.
Musk shared his comments in a series of posts on social media platform X.
Optimus as a von Neumann machine
In response to a post on X that pondered on sci-fi timelines becoming real, Musk wrote that “Optimus will be the first Von Neumann machine, capable of building civilization by itself on any viable planet.” In a separate post, Musk wrote that Optimus will be Tesla’s “biggest product ever,” a phrase he has used in the past to describe the humanoid robot’s importance to the electric vehicle maker.
A Von Neumann machine is a class of theoretical self-replicating systems originally proposed in the mid-20th century by the mathematician John von Neumann. In his concept, von Neumann described machines that could travel to other worlds, use local materials to create copies of themselves, and carry out large-scale tasks without outside intervention.
Elon Musk’s broader plans
Considering Musk’s comments, it appears that Optimus would eventually be capable of performing complex work autonomously in environments beyond Earth. If Optimus could achieve such a feat, it could very well unlock humanity’s capability to explore locations beyond Earth. The idea of space exploration becomes more than feasible.
Elon Musk has discussed space-based AI compute, large-scale robotic production, and the role of SpaceX’s Starship in transporting hardware and materials to other planets. While Musk did not detail how Optimus would fit with SpaceX’s exploration activities, his Von Neumann machine comments suggest he is looking at Tesla’s robotics as part of a potential interplanetary ecosystem.
Tesla exec pleads for federal framework of autonomy to U.S. Senate Committee
Tesla Model Y lineup expansion signals an uncomfortable reality for consumers
