SpaceX's Starship will go interstellar someday, Elon Musk says

a large silver rocket flies through a golden morning sky
SpaceX's Starship rocket launches on its third-ever test flight on March 14, 2024. (Image credit: SpaceX via X)

SpaceX's Starship megarocket could eventually live up to its bold name.

A future iteration of Starship, which conducted its third-ever test flight last week, will go interstellar, according to SpaceX founder and CEO Elon Musk.

"This Starship is designed to traverse our entire solar system and beyond to the cloud of objects surrounding us. A future Starship, much larger and more advanced, will travel to other star systems," Musk said via X early Monday morning (March 18).

Related: Relive SpaceX Starship's 3rd flight test in breathtaking photos

Starship consists of two stainless-steel elements: a huge first-stage booster called Super Heavy and a 165-foot-tall (50 meters) upper-stage spacecraft known as Starship, or just Ship.

Both of these vehicles are designed to be fully and rapidly reusable, and both are powered by SpaceX's next-gen Raptor engine — 33 for Super Heavy and six for Ship.

When stacked, Starship stands about 400 feet (122 m) tall. It's the biggest and most powerful rocket ever built, capable of carrying up to 165 tons (150 metric tons) to Earth orbit in its reusable configuration. For comparison, SpaceX's workhorse Falcon 9 rocket has a maximum payload capacity of about 25 tons (23 metric tons). 

Starship performed quite well on last week's test flight, making serious progress compared to its first two jaunts, which occurred in April and November of last year. For example, the first test mission lasted just four minutes and the second ended about eight minutes after launch. But Thursday's (March 14) flight lasted about 50 minutes, ending when the Ship broke apart during its reentry to Earth's atmosphere

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If you can't see SpaceX's Starship in person, you can score a model of your own. Standing at 13.77 inches (35 cm), this is a 1:375 ratio of SpaceX's Starship as a desktop model. The materials here are alloy steel and it weighs just 225g.

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SpaceX sees Starship helping humanity settle the moon and Mars. NASA buys into this vision: The agency selected Starship to be the first crewed lunar lander for its Artemis program. If all goes according to plan, Starship will put astronauts down on the moon for the first time on the Artemis 3 mission, which is tentatively scheduled to lift off in September 2026.

A lot more work, and many more test flights, will be needed to get Starship ready to carry astronauts in deep space. And getting an interstellar version up and running will require a far bigger leap — one that it's tough to imagine today.

Humanity is nowhere near developing a spacecraft that can travel between the stars on a reasonable timescale; the distances are just so intimidatingly huge. For example, the nearest star to our sun, the red dwarf Proxima Centauri, lies 4.2 light-years away. That's about 25 trillion miles (40 trillion kilometers). It would take a probe powered by conventional rocket propulsion tens of thousands of years to cover that exotic ground. 

Researchers have ideas about how to make the journey more feasible. The Breakthrough Starshot initiative, for instance, is working on a system that would accelerate sailcraft to 20% the speed of light using super-powerful ground-based lasers. Such vehicles could reach Proxima Centauri just 20 years or so after liftoff, if everything works out. 

That's a very big "if." And the Breakthrough Starshot craft would be tiny, with bodies about the size of a postage stamp. Developing an interstellar craft big enough to carry people would be a much taller order. 

That's apparently what Musk has in mind, given that this future interstellar Starship will be "much larger" than the current behemoth. You and I probably won't be around to see that future craft fly, if it ever does; Breakthrough Starshot, which was announced in 2016, has been eyeing a possible debut launch in the 2030s or 2040s, and even that timeline may be ambitious.

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Mike Wall
Senior Space Writer

Michael Wall is a Senior Space Writer with and joined the team in 2010. He primarily covers exoplanets, spaceflight and military space, but has been known to dabble in the space art beat. His book about the search for alien life, "Out There," was published on Nov. 13, 2018. Before becoming a science writer, Michael worked as a herpetologist and wildlife biologist. He has a Ph.D. in evolutionary biology from the University of Sydney, Australia, a bachelor's degree from the University of Arizona, and a graduate certificate in science writing from the University of California, Santa Cruz. To find out what his latest project is, you can follow Michael on Twitter.

  • danR
    There is no iteration of this series that could possibly be thought to be capable of interstellar travel except in the sense of unmanned/robotic/AI probes. Nobody is going to Alpha Centauri in anything less than a nuclear (fission) -powered spacecraft, which makes it rocketry crime that Nixon cancelled the Nerva Program some 50 years ago. Only in the past 10 years has any serious R&D been devoted to this, eg., the NASA/DARPA nuclear hybrid thermal/electric project, but the funding is still a pittance.

    Had NERVA been continued, actual manned missions to the reaches of the solar system could have been realized in the next 10 years.

    Elon is not sending anyone to the stars. It's been, paradoxically, Blue Origin that has been picking up nuclear propulsion contracts; but thanks to Nixon, they'll be at it for another 30 years before BO is stellar-bound.
  • billslugg
    I shook hands with Dick Nixon in Wayne, PA in May of 1968. Little did I know he would go on to commit rocketry crime. He seemed like such a nice guy at the time.
  • Actionjksn
    When they are able to put a Starship into LEO, and then start using other Starships to transfer LOX and methane to it and fill the tanks, while it is orbiting Earth, then I believe it will be capable of making a round trip to Mars.

    Just getting off the ground and then reaching orbit consumes a massive amount of fuel, especially LOX. If you fuel your tanks while in low Earth orbit you eliminate all of that fuel consumption. They need to slingshot out of LEO and head to Mars with full tanks. This also eliminates all of the wind resistance which also burns a lot of fuel. They might even be able to make the entire trip with just one engine, which would really save on fuel, while also saving wear and tear on the other engines.
  • George²
    Actionjksn said:
    They might even be able to make the entire trip with just one engine
    Yes, sure 😁
    One engine to accelerate between 1 and second space speed. Must take more time, and how to balance trajectory when work only one engine?
  • Laz
    musk talks cow farts
  • Classical Motion
    At this present time, the only way to safely go to Mars is with a heavily shielded rotating structure. Lots of mass. And lots of supplies. Lots of mass too.

    It would take lots of fuel for lots of acceleration and lots of deceleration. So we would have to send a complete gas station and grocery/hardware store there to be available.

    And this doesn't include a plan B or a plan C.....for emergencies or hardware failures. It's a location without refuge. You must maintain an environment. A man machine made world.

    It's just not worth the time and money.

    You might possibly send a Starship interstellar, but it could never return. We might not be able to plot a course to another star. Following the star light only works if the craft is going faster than the star. And even then the course is a long curve trajectory, instead of the shortest intersecting bee line at the years future location. One would have to lead a star like leading a target. Even if you could go at light speed. If you aim a laser at a star you will always miss it. Except for Sol of course. Unless Sol's velocity can move it's diameter length in 8 minutes.

    Light does not bend, but emitter motion changes it's angle. Following a moving light is following an angle. Not just distance.
  • Torbjorn Larsson
    Admin said:
    A future, more advanced version of SpaceX's Starship megarocket will travel to other star systems, according to Elon Musk.

    SpaceX's Starship will go interstellar someday, Elon Musk says : Read more
    This is SpaceX president and COO Gwynne Shotwell's ulterior motive, and it is funny to see Musk and Shotwell trade public relation places. He was also the cautious one when Shotwell recently proposed a no-earlier-than six week return to Starship tests, which is a reversal of their usual public communication.

    That they now see a possible survival of the company and a continuous improvement of Starship generations is nice. However, we still don't know if we can travel to the distance stars, even if the discovery of the habitable zone Proxima Centauri b makes for a convenient target for SpaceX colonization efforts.
  • Torbjorn Larsson
    danR said:
    Nobody is going to Alpha Centauri in anything less than a nuclear (fission) -powered spacecraft, which makes it rocketry crime that Nixon cancelled the Nerva Program some 50 years ago.
    Humanity is likely to colonize the Oort cloud eventually, making for a seamless colonization wave into the next star systems over. If we learn to live inside hollowed out resource rich cloud bodies, we would split into an astronomical number of species and few will see any reason for a costly and forgotten gravitational well transit to reach more resources.

    But lets imagine that you want to try a non-generational ship. NERVA was not developed for anything else than to cut interplanetary transit time in half. What early rocket scientists wanted to do was what Germany did when they couldn't stabilize early jet engines, simplify to a pulse engine. In Germany it was the Vi1 engine, in US it was the Orion engine - nuclear bomb pulsed fission/fusion. Such an engine can drive a ship at about 5 % of light speed, which NERVA cannot. If we had wanted, we could have (poisoned Earth and) sent a probe to the stars in the 50s.

    Launching an Orion from a Mars colony would be a great attempt along those lines, the planet is already radiation poisoned due to the thin atmosphere.

    Actionjksn said:
    This also eliminates all of the wind resistance which also burns a lot of fuel. They might even be able to make the entire trip with just one engine, which would really save on fuel, while also saving wear and tear on the other engines.
    The system is designed to use as much thrust it can manage to cut down on travel time, in fact they have said they want to add three more engines on the upper stage.

    What "wind resistance" are you talking about? A launch system to low Earth orbit suffer what is called "gravity loss", which is the net performance loss due to cancel the force of gravity - still 60 % of surface gravity at LEO - as they want to attain orbital velocity. The aerodynamic losses mainly consist of having to compact the atmosphere at supersonic travel around max Q as it leaves the troposphere at around 10 km height - the Karman line for a stable orbit is ten times higher at 100 km. I can read that the total losses for atmospheric drag and gravity drag are 1-2 km/s out of the additional 8 km/s at low Earth orbit so in total a delta-v demand of 10 km/s for launchers.

    It is the high orbital velocity of Earth's huge gravity well that is the problem. After refueling you see that the remaining delta-v work to be done is much the same. "Earth’s surface to LEO is also nearly equal to that required from LEO to surface of Mars."

    Classical Motion said:
    At this present time, the only way to safely go to Mars is with a heavily shielded rotating structure. Lots of mass. And lots of supplies.
    The Starship strategy is - has Musk recently noted - to have the 9 m diameter ship rotate. The rotation acceleration that you can take without adaptation are equivalent of Moon surface gravity and there are hypotheses that long term adaptation would allow a rotation speed that gives an acceleration equivalent to Mars surface gravity.

    The project will launch construction mass (construction material, construction equipment, metalox production plants for propellant and air production) and supply mass with automated ships before they send the first manned crafts.

    The manned crafts will likely not be heavily shielded since they transit for a few months, it is not two year long NASA return missions but colonization transits. Instead they will have their water supply act as a radiation shield specifically for solar CMEs, which will damage humans.