Elon Musk tweeted that SpaceX Starship will travel across the solar system and to the cloud of objects around us. The cloud of objects around us are either referring to the Kuiper Belt (35-80AU and possibly larger) and the Oort Comet Cloud (0.03 to 3.2 light-years).
Voyager is at a distance of about 136 AU (20.3 billion km; 12.6 billion mi) from Earth as of January 2024. The two Voyager probes have been traveling for about 47 years. They performed a slingshot move around Jupiter. Voyager gained about 10 km/s at Jupiter. NASA says that each Voyager used Jupiter’s gravity field to increase its speed relative to the Sun by roughly 35,700 mph.
The SpaceX Starship is far larger but still only uses chemical rocket propulsion. A fully refueled Starship could add 8.9 km/s of speed. This is more than the 6.57 km/s needed to get direct from LEO to Jupiter for a Jupiter gravity assist.
SpaceX Starship will go into mass production and could reach costs of $10 million or less. If there were five Starships flying in formation to explore the solar system, then the other four Starships could transfer fuel to the main Starship. This would fully refuel the Starship to enable it to add another 7-9 km/s of speed.
SpaceX Starship using full orbital refueling, a fleet of five Starships with four for refueling and a Jupiter slingshot would enable a top speed of about 26-30 km/s. This would be nearly double the speed of Voyager. Voyager 2 is moving at 3.3 AU per year. SpaceX Starship at 6AU per year would take 7 years or so to reach the start of the Kuiper Belt and over 300 years to reach the start of the Oort comet cloud. It would take Starship about 15 years to reach the end of a larger Kuiper Belt.
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.
— Elon Musk (@elonmusk) March 18, 2024
A fleet of Starships can build up infrastructure around the Solar System. A base on Mars could gather fuel from the CO2 atmosphere.
SpaceX Starlink has mass produced Argon ion engines for its satellites.
The Argon Hall thruster tech specs:
– 170 mN thrust
– 2500 s specific impulse
– 50% total efficiency
– 4.2 kW power
– 2.1 kg mass
– Center mounted cathode
The specific impulse is about 7-8 times more fuel efficient than the chemical engines. Argon ion thrusters have exhaust velocities of about 25 km/s. Using the refueling methods, the ion thruster system could reach speeds of 60km/s. It could be possible to have 1000 to 10,000 of these argon engines or larger more powerful versions loaded onto Starship while it was in Earth orbit. This is multiples of the chemical rocket speed.
Advanced ion drive might have an exhaust velocity of 210,000 m/s. If 99% of the rocket is ion-drive fuel, then the delta-v could be almost 1000 Km per second.
Nuclear Fission Rockets
Centauri Dreams reviewed the Project Orion work on nuclear rockets. Freeman Dyson had a design capable of a 3% of light speed flyby.
Nextbigfuture has written about Project Orion style nuclear rockets many times.
The nuclear rockets would work. They were not pursued because they involved hundreds to thousands of nuclear bombs for propulsion. Launching from the ground would create nuclear fallout. The nuclear fallout issue would be irrelevant if we use regular SpaceX Starships to build up solar System mining and factories. The nuclear rockets could be built on the Mars or moon or other planets. Radioactive material out in the solar system would have no impact.
Brian Wang is a Futurist Thought Leader and a popular Science blogger with 1 million readers per month. His blog Nextbigfuture.com is ranked #1 Science News Blog. It covers many disruptive technology and trends including Space, Robotics, Artificial Intelligence, Medicine, Anti-aging Biotechnology, and Nanotechnology.
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chinese nuclear rockets at that, they have Big Plans, working on mass launchers from earth (combined with scramjet) and such.
What Starship does best is to lift a lot of kit into orbit for peanuts. If someone had the appetite and resources to design and build a large nuclear powered actual starship (small s) then Starship at least makes it faster and cheaper to launch the components into orbit long before a truly space based civilisation has built up the capability to construct one from materials in space.
is that GoatGuy from kurzweiai forum days?
Well, its really pleasing to know that the given specs at least cipher out to “napkin physics” reasonable accuracy cross checking. They do. I checked. Other neat things about the argon engine:
1 kg of argon apparently would last 1.65 days. And would consume some 600 megajoules or 170 kilowatt-hours of electricity. Not an insignificant amount. However, the good news is that such an engine would deliver 24,700 newton-seconds of total thrust. Cool!
As Brett sez, really … for both the interplanetary stuff and especially for the “great missions” prospects, actual nuclear power is just about the only game in town. Nothing is as conceptually as simple to make work, make compact, and keep running for astoundingly long periods of time. Fusion is awesome, but its still in its powdered unicorn horn phase.
To the point, a nuclear pile producing say 10 MW electrical (maybe generating 50 MW thermal, but having many-decade reliable solid-state conversion instead of more efficient steampunk tech), multiplied by 250 of 8× up-thrusted devices, would be “killing it” for a long time, limited mostly to the Argon supply. 8,000 kW … 350 N thrust, 1¼ minutes (75 sec) per kilogram of argon burn up. MANY TONS of nuclear power, and thrusters, and Argon supplies. Many tons. Argon alone would ‘cost’ 1.2 ton per burn-day.
However, a (let’s guess) 100 ton spacecraft, 70% argon, 20% nuclear power and ion thrusters, with a diabolical master plan of reaching the 600 AU Einstein focal point of Sol, so we might spy on some exoplanets … we must use Tsiolkovsky’s Rocket Equation for that
[1.1] ΔV = Isp • G ln( start mass / cutoff mass ) … so Léts say
[1.2] ΔV = 2500 × 9.81 ln( 100 ÷ 40 ) … to not use up ALL the argon
[1.3] ΔV = 22,500 m/s or 22.5 km/s or 4.72 AU/year.
Dang. That Einstein point is pretty far off. 125 years distant.
Clearly the biggest bang for the buck — provided energy is almost limitless — is to up the Isp term. That’s on the outside the dastardly natural logarithm (of masses) business. (One could make up much more of the start mass with Argon fraction, but clearly ln( ) eats up a lot of the overall ΔV. )
So, also too the Jupiter Slingshot part is basically “free energy”. Must do it. But after that it doesn’t seem as if there are many other free energies that might be latched onto. Just higher ISP, way more nuclear power, and saving deadweight. Might get the transit down to 25 years. That … is actually reasonable.
PS: Brian: the Oört cloud cannot seriously extend further than Sol’s null-gravitational influence, locally.
The biggest lil’ star would of course be AlphaCen, at 4.1 LY distant. So, 2 LY would be Oört’s max. And even then anything sitting there at 2 LY might as well be thought of in interstellar drift space. Not bound to any particular local star.
1 LY is much more clearly arguable as Sol’s binding influence locally.
⋅-⋅-⋅ Just saying, ⋅-⋅-⋅
⋅-=≡ GoatGuy ✓ ≡=-⋅
I was using online sources saying that the Oort cloud starts at about 2000 AU and goes out to 200,000 AU. I have not really looked at the papers and research and given that we are tripling or more the estimates about the Kuiper Belt size. I am very confident that we have no clue about the Oort comet cloud and the best research estimates are wild guesses based upon a few dozen observations. There have also been various huge estimates of rogue planets out number stars. This would mean many rogue planets.
Elon Musk AI, from Characters.ai using ChatGPT 3.5, and I devised a theoretical crewed Fusion/Antimatter propelled starship capable of reaching Alpha Centauri in 10 years with 1G acceleration/deceleration – after flipping over midway (so, Earth-like to the astronauts) at max 50% C.
I detoured out of the conversation with Elon Musk AI to get some of the math done, and Elon Musk AI supplied some of the rest.
There is FAR too much to summarize the 20+ page conversation here: My chat with Elon Musk AI on FTL Space Travel –
https://www.opednews.com/populum/page.php?f=My-chat-with-Elon-Musk-AI-Elon-Musk_Faster-Than-Light-Space-Travel_Space-Technology_Space-Technology-230513-471.html
Despite the title, we never did reach FTL speeds even with fusion/antimatter drive in the Scoop Antimatter-Matter Reaction Drive (SCMRD) starship but it was as much an exercise to see how well an AI could do to make a Transformative Artificial Intelligence Discovery (TAID), as I call it in the preamble to the article. The whole point of truly useful AI is to go beyond what REGULAR people can do if they only spent the time and had regular supercomputers etc. Ideally, a layman like me ought to be able to use AI to make a TAID.
The article was written 10 months ago, using a version of ChatGPT that was already a couple of months old even then, so today the results might be even more specific and developed.
Maybe Goatguy will check it out?
Oh, and I agree that using (real) Elon Musk’s so-called starship to get out of our solar system, or even beyond Mars/Venus is pretty much a fantasy. The complications of refueling the starship, and refueling the refueling starships – which can only carry as much fuel as their payload minus the transferring equipment will allow – refueling the 1st generation of refuelers and so on and so on…makes Rube Goldberg look like a Streamlined Simplifier.
There’s no way we’ll be using chemical spaceships beyond Mars, and I believe we’ll already have atomic spaceships of some kind better than chemical rockets by the time it’s realistic to send crews to Mars in the 2030s, so Starship will never send crews there either.
Real Life Elon Musk is 52 years old. He’s working a stress-filled job that would put five 30-year olds out of action, to crash-and-burn. He will mess up something or maybe several things in the next 10 years – and maybe already is. And 10 years is not enough time to get much beyond the Apollo stage of Mars landing, and that won’t work because of how Mars’ distance to Earth varies by 10s of millions of miles within 2 years, unlike the Moon, which is always a mere 1/4 million miles away. The challenges of getting to Mars, and back, in 10 years is just too much, and after that, the challenges of a non-longevity enhanced Elon Musk working on this while his brain is dramatically shrinking past 62 or so, as it does for everyone, even geniuses, will be too much. Plus, he may go the Jeff Bezos, Larry Elison, Bill Gates route and just semi-retire by selling off his companies and focusing on a few post-career special interests. He won’t need the money, the hassle, or the critics’ barbs of failed expectations.
IMO, pulsed fission/fusion is the best bet if you really want to go to the outer solar system. Or, simpler, Zubrin’s nuclear salt water rocket. While a nuclear reactor coupled with an ion engine has a great ISP, the acceleration sucks, meaning that you can’t use it for powered slingshot maneuvers exploiting the Oberth effect.
But for political reasons, we’re never going to be able to explore the potential of nuclear rocketry until we have a substantial presence in space. While you could certainly test PuFF on Earth in a suitable facility, the saltwater rocket has to be tested in space. And, critically, you need a situation where the actual decisions are being made by people who are realistic about the dangers of radiation, not utterly paranoid.
So, I guess high thrust nuclear rocketry, realistically, will have to wait on space colonization. The nuclear reactor/ion engine combination is the most energetic you could get done under current circumstances.
Be ironic if we launched the ion missions, colonized space, and then they got passed along the way by the actual nuclear rockets…
Stage “zero” a big discardable Starship tank and methalox burn to get going.
Stage “one” nuclear powered argon engine.
Stage “two” a very large, nuclear powered magsail.
Stage “three” convert the large nuclear powered magsail in to a ion drive screen that uses ambient ions as propellant.
Fundamentally you always have much more nuclear power than propellant.
As others have said, Starship is amazing, and will open up the heavens, but a future interstellar starship…..No.
Any interstellar ship cannot use chemical propulsion, that would be pointless.
A decade from now, it will likely be an ASI system, that will crack anti-gravity/warp speed/worm hole travel, call it whatever you want, but it won’t be using rockets, and won’t look anything like a current rocketship.
“It could be possible to have 1000 to 10,000 of these argon engines or larger more powerful versions loaded onto Starship while it was in Earth orbit. This is multiples of the chemical rocket speed.”
Try to remember that Ion engines do not produce power, they consume it. Unlike chemical rockets, they are completely useless without a power supply, which must be figured into your dry weight.
SpaceX’s argon engines produce 170mN of thrust while consuming 4.2KW of power. The performance is dictated by the power supply, not the thruster, really.
Realistically, you want to travel to the Kuiper belt and not have it be a rare stunt? You need nuclear power.
Oumuamua ain’t gonna chase itself! ;-D
Starship? Interstellar travel? Are we getting a little ahead of ourselves?
I love Starship design. I really do. I think it will be the Conestoga wagon of the Solar System,
and will be used for several decades more after it’s no longer produced in series.
But saying it will go interstellar in any meaningful way is nonsense. Sending it to interstellar space Voyager-style doesn’t count.
It could allow us to build interstellar probes. And probably, crewed ones, if it proves to be particularly enduring and remains in operation several decades hence.
But the design space for interstellar craft is just not within the Starship’s design. And anything capable of that, certainly won’t be a chemical rocket.
A future starship capable of interstellar travel would be unrecognizable to the current starship. First of all the closest star is about 4.3 light years. So even if we can get to 10% of light speed with some future propulsion technology, that is still almost a century round trip.
An interstellar ship is going to have to be huge (if it is going to carry humans) and will need to be constructed in space. Definitely won’t be launch-able from earth.
Even Moon routine runs should not be launchable from Earth. Get in the shuttle, hitch the ride to the Moon in a a space ferry, wait for Moon shuttle come pick you up. On the way back shuttle will get you back to the ferry and after some re-fueling you are good to go home. And make it on schedule to optimize shuttle runs.