SpaceX Starship Can Be Better for the Environment Than the Large Cargo Planes

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Commenters have criticisms and concerns about using rockets in place of airplanes for cargo delivery. The 2021 Nextbigfuture prediction of a SpaceX air cargo future was confirmed as a goal by SpaceX board member Antonio Gracias in an April, 2023 All-in-podcast.

Concerns about Pollution and CO2

A Boeing 747 uses about 1 gallon (about 4 liters) of fuel every second. Over the course of a 10-hour flight, it might burn 36,000 gallons (150,000 liters). The 747 burns approximately 5 gallons of fuel per mile (12 liters of fuel per kilometer). Large planes are burning 0.01 gallons per person per mile (5/500). Plane’s are getting 100 miles per gallon (42 kilometers per liter) per person! Not bad when you consider that the 747 is flying at 550 mph (900 kph).

Global fuel consumption by commercial airlines reached an all-time high of 95 billion gallons in 2019. This was about 6 million barrels per day. Global CO2 from commercial aviation is over 1 billion tons.

An Airbus A380 holds 380 tons of fuel. However, the Airbus A380 and all airplanes are air breathing. They get their oxygen from the atmosphere. SpaceX Starship holds 1200 tons of fuel which includes oxygen. One transpacific flight would be 720 tons of CO2 for the largest Airbus versus 675 tons for the SpaceX Starship. The 720 tons of CO2 for the Airbus is a calculation by Andrew Steele. Everyday Astronaut has slightly different numbers that give an advantage to the largest airplanes for CO2.

The cargo 747-200 can carry 105 tons of payload up to 6800 nautical miles.

The single stage starship will have range of about 6000-8000 mile and could achieve payloads of 200-300 tons on a suborbital flight.

If Suborbital Starship has 200 tons of payload then the per transpacific flight CO2 would definitely be less by cargo weight. If Suborbital Starship has 300 tons of payload then the per transpacific flight CO2 would definitely be less by cargo weight than a 747-200 cargo plane.

Most of the rocket thrust would be in the first few minutes before it reaches the Mesosphere and minimally in the Stratosphere.

When SpaceX Starship is flying passengers, because the flight time will be about 30 minutes this will enable high density seating. It will be like a longer roller coaster ride. Up to 1000 people can fly at each flight.

Rocket Pollution

From Goatguy
Moving to a world of hourly rockets from perhaps hundreds of worldwide shipping ports, 365 days a year means millions of tons of CO2 and H2O methane-burn byproducts being injected to both the lower and higher atmospheres. Stratosphere and beyond.

Now, let us recall that when the out-of-the-blue South Pacific volcano blew its top a couple of years ago in the ‘most significant eruption since Krakatoa’ as many reporters dutifully quipped, it wasn’t too long before the climatologists were seeing the stratospheric plume of H2O as potentially being a significant contributor to long-term global warming, water vapor being such an efficient blanket gas.

So I ask, what of this, in the context of hundreds of thousands of rocket shots a year going down? Of course it isn’t in the interest of the rah-rah team(s) to notice the little turds in the punch bowl. But there they are. Turds.

Color me purple and call me an eggplant … but I’ll be equally purple with surprise should the environmentalists fail to wake up and forget to bytch about this new polluter.

Tim Dodd the Everyday Astronaut went over the pollution of rockets.

Methane, or (when burnt with liquid oxygen) methalox. SpaceX’s Starship, Blue Origin’s New Glenn’s first stage and ULA’s Vulcan first stage run on Methane.

Methalox is probably the next most clean after hydrogen, which makes sense since it is such a similar compound. So when burnt, methane just becomes CO2 and water vapor along with a bit of NOx as well. Methane in the atmosphere is a powerful greenhouse gas but when burned and split into CO2 and H20 there is less warming.

Methane’s solar absorption sets off a cascade of events that reduces its overall warming effect by about 30 percent, researchers report March 16 in Nature Geoscience. They ysed a computational model of Earth’s climate. When they took the traditional approach — considering only methane’s longwave absorbance — they estimated that the gas has caused 0.2 degrees Celsius of warming since preindustrial times, out of 1.06 degrees C total warming. But when they also included shortwave absorbance, methane’s contribution to warming fell to about 0.16 degrees C. In addition to warming the planet, methane is also thought to increase global precipitation, due to greater evaporation of water with higher temperatures. But the researchers found that inclusion of shortwave absorbance also reduced methane’s precipitation effect, from a predicted 0.3 percent increase in precipitation (based on longwave absorbance alone), down to an increase of about 0.18 percent.

The Starship would not need a booster for point-to-point travel on Earth. This would mean 25% of the CO2 emissions of a full stack Super Heavy Starship. This would be 675 tons of CO2 per flight.

Other Issues

Other concerns were about sound pollution, terrorism, landing issues and if there is a market for sub-24 hour international deliveries. These will be addressed in follow up articles.

21 thoughts on “SpaceX Starship Can Be Better for the Environment Than the Large Cargo Planes”

  1. This is all BS analysis, totally flawed!
    747 and A380 comparison is really bad as they are the least efficient due to long range (Breguet range equation) + extra structure weight to carry fuel which makes efficeincy exponentially inefficient.
    And 747 and A380 are only a tiny percentage of total aviation travel miles or kms, whereas 737 like travel in vast mojority.
    But hidden in the charts the 737 data 5.5X better and new battery tech and LH2 for long range will soon allow zero emissions so SpaceX needs to align with Tesla and use LH2 fuel.
    How long does the stratospheric water take to descend via precipitation with the extreme cold? A very long time from the little I could find.

  2. I could see transportation hubs being built 60-100 miles outside of urban centers / manufacturing bases. The deserts around Los Angeles, the prairies around Dallas/Fort Worth, the swamps around NYC, the short woods around Chicago, etc.

    20 years ago, 25 miles north of Fort Worth, TX, Ross Perot Jr. built the first industrial airport (Alliance Airport). No passenger service, just a freeport cargo/transportation hub connecting major freeways, railroads, and air freight. Fedex, Amazon, and Burlington Northern Railroad are some of the major tenants. At the time it was built, it was in the middle of nowhere. Now it is one of the highest-growth areas in the nation

    “According to the airport’s operations data for 2021, Alliance Airport experienced a 43% year-over-year volume increase in cargo transported. The airport reported 789,429,648 pounds of cargo enplaning and deplaning in 2021, compared to 550,762,202 pounds in 2020.

    This growth stems from a variety of factors, including increased efficiencies and lower operating costs, a dramatic shift in consumer behavior and an increase in e-commerce shipping activity.

    FedEx’s AllianceTexas-based Southwest Regional Sort Hub is ranked third in the U.S. in terms of square footage of sortation and handling facilities. Alliance Airport is also home to one of Amazon Air’s regional air hubs enabling wider selection and faster delivery to customers across Texas and the region.”

    • Not at any level we’re likely to see in the next century, no. We’d run out of fossil fuels before the level actually got dangerously high.

      • I’ve seen some research testing that, and they found that shell forming organisms seem to readily adapt to gradual changes in CO2 levels. After all, there was a lot of coral formation during periods when the atmospheric CO2 level was enormously higher than at present.

        People often forget that the CO2 level at the beginning of the ‘Antropocene’ was radically lower than during essentially the entire past history of the planet. (Except right at the end of the Carboniferous era, on account of a ridiculous amount of carbon having been sequestered faster than volcanos could replace it.) This is mostly glossed over by either looking at restricted time period, or sometimes using a log scale on the x axis.

        Shell forming organisms, such as Nautaloids, and, yeah, coral, first appeared about 520 million years ago, during the Ordovician era. When CO2 levels ranged from 3,000-9,000 ppm, compared to today’s 400 ppm.

        So, yes, one presumes the oceans gets a bit more acid as CO2 levels rise, but we have plenty of evidence that they don’t get acid enough to cause problems.

        • Timescales are the problem. Organisms need time to adapt. If things are happening over the timescale of 10s of millions of years (as in your example) then organisms manage the change.

          But this speed (1000s of years) is a factor of 1000 faster. The blink of an eye in geological terms: much more destructive. The difference between spreading some manure on your garden and bursting a slurry dam over it.

          • We’re talking plants & sealife adapting to increased Co2, plants & Animals don’t work geological timescales, they adapt almost instantly, growing faster, breeding & seeding more. Within a generation (which can be VERY short depending on species!) you can see massive growth, never mind multiple generations which is waaaay faster than geological time.

            Part of why co2 isn’t so high now is because western nations have let the trees regrow after cutting most down in the 1800 and early 1900’s for firewood and building materials.

  5. Point to point ballistic transport on earth will never be more than a niche market for military use in war. Ballistic transport may or may not be able to deliver passengers (and / or cargo) halfway across the globe at a lower CO2 cost per ton than conventional airliners, but if CO2 cost per ton is the metric, there are alternative designs that would score far better than any ballistic rocket.

    The optimal design would be 2.5 stages. The “.5” stage would be an inclined launch ramp that would accelerate a two stage vehicle electromagnetically to perhaps 500 km / hr. The launch ramp would be a significant piece of infrastructure, but it would allow the rocket engines to light up a couple of thousand feet in the air. That avoids launch pad damage issues and mitigates noise. The first stage engines would be low ISP booster engines burning a small amount of LOX and LNG, with a larger amount of inert propellant injected to boost thrust. Liquid argon might be a good candidate. At 1% of the atmosphere, it’s cheap, not a greenhouse gas, and no amount of it released into the upper atmosphere is going to do anything to the ozone layer.

    The second stage would be a “shockwave rider” with relative low thrust, high impulse LOX – LNG engines. Its engines would accelerate it to something around mach 10. It would then skip along the top of the atmosphere, losing a bit of its velocity with each skip. After 2 – 4 skips, it would glide to a conventional horizontal landing at its destination airport.

    The injection of inert propellant mass in the booster stage to reduce ISP may seem counterintuitive . It does substantially increase the total reaction mass expended per ton of payload delivered; that’s why it’s a two stage design. But it reduces the amount of carbon expended.

    • Currently rockets light up on the pad while retained by clamps, which release only once everything is verified to be running properly. It would be pretty risky to toss them a thousand feet into the air and then ignite; If you had a problem you’d lose the rocket.

      Maybe once things are well established to be reliable. For cargo only.

      • The launch ramp would be inclined, not vertical. If engines failed to ignite, the vehicle might, in principle, have enough horizontal velocity to turn around and land safely. Though horizontal landing of a fully fueled 2-stage system might be problematic. Better to have super-reliable engines on the booster stage. Given that they’d be flying multiple times per day, that doesn’t seem unreasonable.

        BTW, the idea of hypersonic atmospheric skip is far from new. The Germans in WW II were looking into designs for a modified A4 rocket with an upper stage capable of bombarding New York and Washington.

  6. Once SpaceX moves to hydrogen rockets than the savings for the environment will be significant.

    • If the CH4 (methane) is produced from the atmospheric CO2 (by Sabatier, i.e.) using green energy (solar), the net CO2 exhaust of a Starship flight will be very-very close to zero.

      • What’s the difference in effects of CO2 on ground levels (Sabatier process or comparable innovations) and Troposphere(6-20km)/Stratosphere(-50km)(/Mesosphere(-85km)) (“Most of the rocket thrust would be in the first few minutes before it reaches the Mesosphere and minimally in the Stratosphere.”)

        “From 1850 until 2022, the ocean has absorbed 26 % of total anthropogenic emissions. However, the rate at which the ocean will take it up in the future is less certain. Even if equilibrium is reached, including dissolution of carbonate minerals, the increased concentration of bicarbonate and decreased or unchanged concentration of carbonate ion will give rise to a higher concentration of un-ionized carbonic acid and dissolved CO2. This higher concentration in the seas, along with higher temperatures, would mean a higher equilibrium concentration of CO2 in the air.
        Carbon moves between the atmosphere, vegetation, the soil, the surface layer of the ocean, and the deep ocean. From 1850 until 2022, the ocean has absorbed 26 % of total anthropogenic emissions.”

        What technical processes consume CO2 (air moisture suction) on low energy input levels?

  7. Point to point will never happen because of noise. Crazy loud at takeoff and very large re-entry boom footprint – as it dissipates huge orbital energy.

    And it would also be shut down by environmentalists concerned about long (climate altering) residence time of water vapour in stratosphere

    • “Most of the rocket thrust would be in the first few minutes before it reaches the Mesosphere and minimally in the Stratosphere.”

    • I live next to Kennedy space center, and have lived next to airports and railways, sure rockets are louder.

      BUT SO MUCH LESS ANNOYING THAN THAT MUTHER FUGGING HIGH PITCHED JET WHINE.

      A rocket Is more like a train passing by, a bit of rumble and shake. so unless you really hate the rumble of thunder or trains, it’s not bad at all.

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