Starship Space Shade Plan Faces $2 Quadrillion Cost, Vast Emissions

Space Shades: Humanity's Last Hope | Answers With Joe — Joe Scott

Joe Scott

Deploying an orbital sunshade constellation to halt global warming would bankrupt the world economy and emit billions of tons of carbon dioxide, making direct terrestrial clean energy investment far more practical.

AI-assisted summary of Space Shades: Humanity's Last Hope | Answers With Joe — original source. Check the original for full context.

Source published:

Key ideas

  • Blocking just 2% of incoming sunlight at Lagrange Point 1 (L1) would offset accumulated global warming, requiring an occluding surface area of roughly 2.6 million square kilometers—equivalent to about one-third of the continental United States. (5:01)
  • Deploying such a shield from Earth using SpaceX Starship within a 10-year window would demand nearly 2.9 million launches—roughly 719 launches every single day—costing trillions in launch operations alone. (9:41)
  • Manufacturing the estimated 43.5 billion steerable shades would cost upwards of $2.175 quadrillion to $4.35 quadrillion, far surpassing total global gross domestic product of approximately $81 trillion. (11:18)
  • The 2.9 million Starship launches would inject roughly 7.7 billion metric tons of CO2 directly into Earth's atmosphere, substantially undermining the environmental benefits of the shade. (16:59)
  • A more technically feasible alternative involves autonomous lunar manufacturing and electromagnetic railguns, though researcher Roger Angel notes the same capital applied directly to terrestrial renewable energy would deliver far better and permanent results. (20:39)

Detailed notes

## Background Published on YouTube on August 3, 2020, by science communicator Joe Scott on his channel Answers With Joe, this video investigates the concept of placing a massive solar shade in space as a last-resort geoengineering solution to runaway climate change. Grounded in research by astronomer Roger Angel and astrophysicist Ethan Siegel, the presentation examines the scale, cost, launch logistics, and physical feasibility of blocking solar radiation to cool the planet.

## TL;DR Joe Scott conducts a detailed engineering and economic thought experiment to determine whether deploying a sunshade at Lagrange Point 1 (L1) could realistically reverse global warming by blocking 2% of solar irradiance. Calculating the required 2.6 million square kilometer coverage area, he demonstrates that deploying the array using SpaceX's Starship would demand nearly 2.9 million launches, cost trillions or quadrillions of dollars, and emit billions of tons of carbon dioxide during launch alone. After examining speculative workarounds such as autonomous lunar manufacturing and electromagnetic railguns, Scott concludes that treating space shades as an emergency escape hatch is an impossible distraction, echoing Roger Angel's verdict that the same capital and innovation should be applied directly to terrestrial clean energy.

## Atmosphere & style The presentation blends conversational, geeky enthusiasm with sharp, deadpan wit, pulling viewers along a thought experiment that rapidly escalates from plausible sci-fi optimism into mathematical absurdity. Scott balances accessible visual comparisons—like stacking trillions of dollar bills past the Sun to Mars—with rigorous orbital mechanics, delivering sobering realities with a lighthearted, self-deprecating touch. The narrative arc moves from curious exploration to incredulity at the sheer logistical impossibility, ultimately landing on a grounded, pragmatic plea for investing in real-world environmental action.

## Bulletin - [05:01](https://www.youtube.com/watch?v=6yqi0FabHHs&t=301s) Blocking just 2% of incoming sunlight at Lagrange Point 1 (L1) would offset accumulated global warming, requiring an occluding surface area of roughly 2.6 million square kilometers—equivalent to about one-third of the continental United States. - [09:41](https://www.youtube.com/watch?v=6yqi0FabHHs&t=581s) Deploying such a shield from Earth using SpaceX Starship within a 10-year window would demand nearly 2.9 million launches—roughly 719 launches every single day—costing trillions in launch operations alone. - [11:18](https://www.youtube.com/watch?v=6yqi0FabHHs&t=678s) Manufacturing the estimated 43.5 billion steerable shades would cost upwards of $2.175 quadrillion to $4.35 quadrillion, far surpassing total global gross domestic product of approximately $81 trillion. - [16:59](https://www.youtube.com/watch?v=6yqi0FabHHs&t=1019s) The 2.9 million Starship launches would inject roughly 7.7 billion metric tons of CO2 directly into Earth's atmosphere, substantially undermining the environmental benefits of the shade. - [20:39](https://www.youtube.com/watch?v=6yqi0FabHHs&t=1239s) A more technically feasible alternative involves autonomous lunar manufacturing and electromagnetic railguns, though researcher Roger Angel notes the same capital applied directly to terrestrial renewable energy would deliver far better and permanent results.

## Key takeaways - [01:21](https://www.youtube.com/watch?v=6yqi0FabHHs&t=81s) Planetary surface temperature is determined by incoming solar radiation and atmospheric heat retention; altering solar input becomes an option if emissions cuts cannot prevent tipping points. - [01:21](https://www.youtube.com/watch?v=6yqi0FabHHs&t=81s) Terrestrial geoengineering techniques like stratospheric aerosol injection mimic volcanic events but carry unpredictable, virtually irreversible ecological risks. - [03:51](https://www.youtube.com/watch?v=6yqi0FabHHs&t=231s) Lagrange Point 1 (L1), situated 1.5 million kilometers sunward from Earth, is the ideal orbital station because solar and terrestrial gravitational forces balance out. - [05:01](https://www.youtube.com/watch?v=6yqi0FabHHs&t=301s) Geometric calculations show that a 2% reduction in solar irradiance requires a sunshade spanning 2.6 million square kilometers at L1. - [07:16](https://www.youtube.com/watch?v=6yqi0FabHHs&t=436s) A modular swarm of mid-sized, steerable shades is superior to a single monolith or uncontrolled dust clouds, offering structural redundancy and controllable solar deflection. - [09:41](https://www.youtube.com/watch?v=6yqi0FabHHs&t=581s) Maximized cargo packing inside SpaceX Starship limits payload to flat discs, requiring 15,000 stacked shades per launch to cover 0.9 square kilometers per flight. - [09:41](https://www.youtube.com/watch?v=6yqi0FabHHs&t=581s) Achieving the 2.6 million km² target in 10 years would require 719 Starship launches daily, a cadence physically impossible with current or near-future infrastructure. - [11:18](https://www.youtube.com/watch?v=6yqi0FabHHs&t=678s) Constellation manufacturing costs range between $2.175 quadrillion and $4.35 quadrillion, which is tens of times larger than total annual global GDP. - [13:40](https://www.youtube.com/watch?v=6yqi0FabHHs&t=820s) Purely opaque shades would act as uncontrollable solar sails; materials must scatter light (such as Fresnel lenses or diffusive glass) or reradiate thermal heat to remain on station. - [16:59](https://www.youtube.com/watch?v=6yqi0FabHHs&t=1019s) Station-keeping thrusters would face severe fuel scarcity, as global xenon production is just 6 tons annually and argon supplies are heavily committed to other industries. - [16:59](https://www.youtube.com/watch?v=6yqi0FabHHs&t=1019s) Rocket exhaust from nearly 2.9 million Starship flights would release 7.7 billion tons of CO2, creating an emissions burden comparable to global commercial aviation. - [20:39](https://www.youtube.com/watch?v=6yqi0FabHHs&t=1239s) Relocating production to the Moon leverages low gravity, abundant regolith, and lack of atmospheric friction, enabling lunar railguns to launch pre-assembled shade pods toward L1. - [22:19](https://www.youtube.com/watch?v=6yqi0FabHHs&t=1339s) Sunshades act strictly as a temperature band-aid and fail to resolve secondary greenhouse gas impacts, including ocean acidification. - [24:17](https://www.youtube.com/watch?v=6yqi0FabHHs&t=1457s) Even sunshade pioneer Roger Angel concluded that applying the massive capital and technological effort directly to terrestrial clean energy provides a vastly superior, permanent solution.

## Detailed walkthrough ### [00:00](https://www.youtube.com/watch?v=6yqi0FabHHs&t=0s) Climate Urgency and Drastic Solutions

While the energy transition is showing signs of progress—renewable power is expanding rapidly, cleaner technologies are transforming the electric grid, and major automotive manufacturers are finally taking electric vehicles seriously—it remains insufficient. Global population growth and expanding industrialization in developing countries mean carbon dioxide emissions continue to break records annually. Faced with increasingly dire projections from climate scientists, humanity risks crossing an irreversible tipping point where conventional decarbonization cannot act fast enough.

```mermaid flowchart TD accTitle: Planetary Energy Balance accDescr: The two core drivers determining planetary surface temperatures. subgraph Drivers["Planetary Heat Mechanics"] A["Incoming Solar Radiation"] --> C["Planetary Temperature"] B["Atmospheric Trapping (Greenhouse Effect)"] --> C end ```

In the search for drastic interventions, an idea frequently brought up is placing a massive solar shade in space to intercept sunlight before it reaches Earth, bringing average global temperatures back to pre-industrial baselines. As Joe Scott introduces his deep dive into the engineering and logistical reality of this proposal:

> “Assuming things continue at this pace we may reach a point of no return, a point where it's going to take something really drastic to turn things around.”

[01:21](https://www.youtube.com/watch?v=6yqi0FabHHs&t=81s) Terrestrial Geoengineering and Its Risks

At a fundamental level, planetary temperature is dictated by just two factors: the volume of solar radiation entering the system and how much of that heat the atmosphere traps. While cutting emissions to restore atmospheric equilibrium is the safest route, modifying incoming solar radiation becomes an attractive alternative if emissions cuts fall short. Earth-based geoengineering concepts attempt this within the atmosphere:

- **Cloud Seeding:** Injecting particles into the upper atmosphere to create high-albedo, reflective cloud decks. The downside is their ephemeral lifespan, which would demand thousands of continuous jet flights emitting vast quantities of greenhouse gases, largely defeating the initial purpose. - **Stratospheric Aerosols:** Injecting reflective dust or sulfur dioxide directly into the stratosphere, modeled after historical volcanic eruptions. - **Volcanic Analogues:** On June 15, 1991, Mount Pinatubo in the Philippines blasted 15 million tons of sulfur dioxide into the stratosphere, dispersing a global haze that reduced global average temperatures by 1°C over the following year. A similar phenomenon occurred with the 1815 eruption of Mount Tambora, resulting in the notorious "Year Without a Summer." Mount Pinatubo, however, was the first event observed in real time by orbital satellites.

Despite being technically plausible using high-altitude balloons, deploying 15 million tons of aerosols into the stratosphere carries immense risks. The ecological side effects cannot be predicted in advance, and atmospheric geoengineering is exceedingly difficult to reverse once initiated. Scott cautions against recklessly altering our atmosphere, noting that “it wasn't the machines that blacked out the sky in The Matrix.”

[03:51](https://www.youtube.com/watch?v=6yqi0FabHHs&t=231s) Placing the Shade at Lagrange Point 1 (L1)

If humanity set a 10-year deadline to construct an extraterrestrial shade to bypass atmospheric risks, the very first step would be determining where to station it. The location dictates the dimensions the shade requires. Stationing an object between the Sun and Earth points directly to Lagrange Point 1 (L1).

Lagrange points represent orbital gravitational balance areas where the competing pulls of the Earth and the Sun, along with orbital mechanics, keep an object in a fixed position relative to Earth:

- **Lagrange Point 1 (L1):** Located roughly 1.5 million kilometers sunward between Earth and the Sun, directly inline with solar radiation. - **Lagrange Point 2 (L2):** Located on the opposite side of Earth, away from the Sun, serving as the future station for deep-space observatories like the James Webb Space Telescope.

```mermaid flowchart LR accTitle: Orbital Alignment of L1 and L2 accDescr: Spatial order from the Sun through Earth to the James Webb Space Telescope position. Sun["Sun"] --> L1["L1 (1.5M km from Earth)"] L1 --> Earth["Earth"] Earth --> L2["L2 (JWST Location)"] ```

Scott explains the orbital mechanics to newcomers:

> “L1 stands for Lagrange Point 1, and Lagrange points are areas around the Earth or any orbiting body for that matter where the gravity of the Earth and the gravity of the Sun kind of even each other out.”

[05:01](https://www.youtube.com/watch?v=6yqi0FabHHs&t=301s) Calculating the Shade Area: 2.6 Million Square Kilometers

According to feasibility models—specifically astrophysicist Ethan Siegel’s analyses on *Starts With A Bang* and an exhaustive 2006 study published in the *Proceedings of the National Academy of Sciences* (PNAS) by Professor Roger Angel—humanity does not need to block the entire Sun. Shading just 2% of the incoming solar radiation would be sufficient to counteract accumulated warming and restore pre-industrial climate conditions.

Calculating that 2% requires first determining the footprint of a 100% occlusion disk at L1: - Earth's physical diameter is 12,742 kilometers. - Because the Sun is much larger than Earth, incoming sunlight forms a tapered cone. L1 sits 1.5 million kilometers upstream along that cone, approximately 1% of the total 149.6-million-kilometer distance between Earth and the Sun. - Factoring in this geometry, the required coverage diameter at L1 expands by roughly 1% to **12,869 kilometers**. - Applying the area of a circle ($\pi r^2$) produces a 100% cross-sectional area of **129,984,558 square kilometers**. - A 2% reduction requires blocking **2,599,691 square kilometers**, rounded off to **2.6 million square kilometers**.

To contextualize that size for the viewer:

> “Well it comes out to almost exactly the combined areas of the states of Washington, Oregon, California, Nevada, Utah, Idaho, Arizona, Montana, and Wyoming. About a third of the continental United States.”

Covering a footprint that massive qualifies as a colossal megaproject.

[07:16](https://www.youtube.com/watch?v=6yqi0FabHHs&t=436s) Monolith vs. Swarm Architecture

Building an umbrella measuring 2.6 million square kilometers cannot happen in a single launch; it necessitates an architectural framework that can be assembled or coordinated in deep space. Three distinct configurations present themselves:

1. **A Single Monolithic Shade:** - *Advantages:* Offers simplified command and control over a single consolidated vehicle. This simplicity matters because L1 is technically meta-stable ("stable-ish") and demands continuous station-keeping maneuvers against solar radiation pressure and orbital perturbations. - *Disadvantages:* Lacks redundancy. A strike by an errant piece of space debris could tear or spin the entire structure out of alignment. Furthermore, assembling millions of square kilometers requires endless dockings, each presenting an opportunity for critical failure.

2. **A Free-Flying Swarm of Independent Shades:** - *Advantages:* Provides modularity and structural redundancy. If individual units degrade or fail, the larger array continues functioning. - *Disadvantages:* Introduces a heightened probability of collisions among neighboring units should guidance and attitude thrusters fail.

3. **A Cloud of Micro-Shades:** - Breaking the concept down into microscopic or lightweight components distributed en masse across the L1 region.

[08:14](https://www.youtube.com/watch?v=6yqi0FabHHs&t=494s) The Mid-Size Steerable Shade and the Starship Constraint

Evaluating the various concepts for solar radiation management, dumping an uncontrolled cloud of micro-shades, dust, or reflective debris into space to create an artificial haze suffers from the exact same fatal flaw as atmospheric geoengineering: it is essentially permanent, leaving humanity completely helpless if catastrophic unintended consequences arise. Because of this, Joe Scott favors mid-sized shades equipped with autonomous guidance units as the ideal compromise. With steerable shades, correcting an over-cooling mistake is as simple as rotating them sideways to let more sunlight through.

When considering shade geometry, engineers might be tempted to build enormous structures that rely on elaborate origami-like folding mechanisms that unfurl once deployed—much like modern satellite solar panels. However, Joe dismisses mechanical origami because moving parts introduce immense mechanical complexity, higher weight, and dozens of potential failure points. The real objective is to maximize the surface area delivered to the Sun-Earth Lagrange point 1 (L1) per launch using flat, simple, inexpensive discs that fit snugly inside a standard rocket fairing. To achieve maximum throughput, the mission demands the largest payload fairing available, which points squarely to SpaceX’s Starship:

```mermaid flowchart TD accTitle: Launch Fairing Diameter Comparison accDescr: A comparison of payload fairing widths across major rockets evaluated for sunshade deployment.

subgraph Fairings ["Rocket Fairing Diameters"] A["Saturn V / New Glenn<br>6.6 meters"] B["SLS Block 2 Cargo<br>8.4 – 10.0 meters"] C["SpaceX Starship<br>9.0 meters wide x 18.0 meters tall"] end

A -.->|"Insufficient volume"| D["Space Shade Deployment"] B -.->|"Expendable / Prohibitively costly"| D C ==>|"Fully reusable & maximum volume"| D ```

While NASA’s Saturn V carried a 6.6-meter payload fairing (comparable to Blue Origin’s New Glenn) and the proposed Space Launch System (SLS) Block 2 cargo vehicle could range between 8.4 and 10 meters, Starship remains the only viable contender. Starship offers a payload bay 9 meters wide by 18 meters tall, but its defining advantage is full reusability. As Joe Scott argues:

> “I'd argue that the Starship is really the only way to do this; you would have to have a fully reusable vehicle, and Starship's the only vehicle literally ever built that could do that.”

---

[09:41](https://www.youtube.com/watch?v=6yqi0FabHHs&t=581s) The Launch Math: From Fairing Limits to Absurdity

To see what launching a planetary sunshade looks like in practice, Joe Scott constructs an aggressively optimistic thought experiment. Assuming each circular shade can be engineered down to a razor-thin 1 millimeter thickness with an 8.75-meter diameter—leaving just enough edge clearance inside Starship’s 9-meter fairing for guidance modules—a single shade would dwarf an average person and cover roughly 60 square meters of surface area.

Because Starship cannot reasonably travel the entire 1.5-million-kilometer distance out to L1 and back, roughly 3 vertical meters of fairing height must be reserved for an onboard propulsion kick stage. This leaves 15 meters of usable vertical cargo height:

- **Shade dimensions**: 8.75 m diameter, 1 mm thick (~60 m² area per unit) - **Stacking capacity**: 15,000 shades packed into 15 vertical meters of fairing space - **Coverage per Starship launch**: 900,000 m² (0.9 km²) - **Total coverage target**: 2.6 million km² (to achieve a 2% reduction in solar irradiance) - **Total launches needed**: 2,888,888 launches

The launch cadence required to hit that target quickly spirals into sheer impossibility: - At a cadence of **one Starship launch every single day**, deploying the constellation would take **7,914 years**. - To complete deployment within an urgent **10-year window**, humanity would need to sustain **719 launches every single day**—amounting to one Starship lifting off every two minutes, 24 hours a day, for an entire decade.

---

[11:18](https://www.youtube.com/watch?v=6yqi0FabHHs&t=678s) Trillions and Quadrillions: Tallying the Impossible Bill

Even if the logistical bottleneck of launching every two minutes could be overlooked, the financial figures alone break the model entirely. Grounding launch cost estimates on Elon Musk’s November 2019 remarks to Air Force Lieutenant General John Thompson—where Musk projected an ultimate operating cost of $2 million per Starship flight—2,888,888 launches would cost $5.8 trillion purely in launch operations, without accounting for upper-stage propulsion or ground operations.

The manufacturing costs for the hardware are vastly more punitive. SpaceX manufactures Starlink satellites at roughly $250,000 per unit. While a passive shade disc seems simpler than an active communications satellite, operating autonomously 1.5 million kilometers away requires dedicated inter-satellite networking, thrusters, and autonomous station-keeping systems that can never be serviced:

- **Unit cost assumption**: $100,000 per shade disc - **Constellation size**: 43.5 billion individual shades (15,000 shades across ~2.9 million launches) - **Base manufacturing price tag**: $4.35 quadrillion

Even when cutting that unit estimate in half to $50,000 to generously factor in unprecedented economies of scale, the bill still totals $2.175 quadrillion. To illustrate just how incomprehensible that number is, Joe notes that stacking $2.175 quadrillion in physical one-dollar bills (at a standard thickness of roughly five bills per millimeter) creates a stack stretching 435 million kilometers:

> “That's far enough to reach the Sun, and then keep going and hit the Earth's orbit on the other side of the Sun, and then hit Mars.”

That physical stack of currency would cross the distance between Earth and the L1 Lagrange point 290 times over. Compared to the total global gross domestic product of approximately $81 trillion, manufacturing the shade array alone would cost nearly 26 times the annual economic output of planet Earth. As Joe summarizes: “Okay, so there's literally not enough money in the world to do this.”

---

[13:40](https://www.youtube.com/watch?v=6yqi0FabHHs&t=820s) Materials, Solar Wind, and the Fresnel Alternative

Beyond the absence of monetary capital, planet Earth faces severe material constraints. Shading 2.6 million square kilometers requires fabricating an artificial structure equal to the land area of two Colombias—or the entirety of Kazakhstan. The material selected must be super-abundant, dirt cheap, remarkably strong to survive rocket vibrations at a 1-millimeter thickness, and counterintuitively, somewhat transparent.

Drawing on the research paper by astronomer Roger Angel, Joe explains that a fully opaque sunshade placed in deep space would absorb the brute force of solar photons and the solar wind, acting as an unmanageable solar sail that gets pushed out of alignment. To stay in station, the disc must disperse or deflect photons rather than absorb their momentum:

- **Porous Sails**: Ultra-thin membranes perforated with micro-pores that let controlled amounts of radiation leak through. - **Micro-Slats**: Louvered venetian-blind style slats that deflect incident sunlight away at oblique angles. - **Diffusive Glass**: Highly specialized, ultra-thin silicate glass sheets (similar to advanced Gorilla Glass) that scatter light rather than block it. - **Fresnel Lenses**: Refractive sheets positioned to gently bend solar rays outward around Earth's orbital path. This method requires significantly greater surface area than pure shades to achieve the same cooling effect. - **Radiative Back-Surfaces**: Materials engineered to absorb photon energy on the sun-facing side and reradiate it out the back as thermal infrared heat to cancel out solar radiation pressure.

Procuring raw materials at this planetary scale would almost certainly require deep-sea floor strip-mining to avoid destroying vast swaths of populated farmland and continents.

---

[15:24](https://www.youtube.com/watch?v=6yqi0FabHHs&t=924s) The Industrial Scale and the Last-Ditch Paradox

The manufacturing infrastructure required to feed a 10-year deployment schedule would fundamentally reshape global geography. At 719 (or roughly 791) launches per day carrying 15,000 shades apiece, manufacturing plants would have to fabricate an astonishing 11,866,000 shades every single day.

Transporting nearly 12 million fragile, 8.75-meter wide glass discs daily across public highway or rail networks is physically impossible. The only logistical solution would be constructing hundreds of massive, dedicated manufacturing and launch megacomplexes directly adjacent to ocean coastlines worldwide, stamping out discs and immediately loading them into waiting Starship fairings.

This exposure of the industrial reality shatters the fantasy that space shades can serve as an emergency fallback plan:

> “The reason I've been using this arbitrary 10-year, you know, timeline here is because every single time people talk about this idea, it's sort of like a last-ditch effort; it's the thing that you do when everything else has failed and our entire existence hangs in the balance.”

If such a mega-engineering endeavor were ever actually undertaken, it could only realistically succeed as a multi-generational megaproject spanning at least a century. Yet framing space shades as a "last-ditch rescue plan" assumes humanity is already facing immediate climate catastrophe—a scenario where civilization has years, not centuries, to act.

[16:59](https://www.youtube.com/watch?v=6yqi0FabHHs&t=1019s) Resource Scarcity, Thruster Fuels, and Rocket Emissions

Beyond the pure financial expense, the material extraction alone would be destructive to the planet, and the energy required to manufacture the shades is staggering. Worse still, there might not even be enough propellant to keep them stable once deployed at Lagrange point 1 (L1). The sunshades require control thrusters for station-keeping, which points toward ultra-efficient systems like miniaturized ion drives. However, these systems rely on noble gases such as xenon or argon. Xenon is essentially a non-starter because global production is only about six metric tons per year. While humanity produces roughly 700,000 metric tons of argon annually, it is already heavily utilized across other industries, leaving its viability as a dedicated shade propellant an unresolved question mark.

Another critical issue is decommissioning. Roger Angel estimated each shade would have an operational lifespan of roughly 20 to 30 years. Once they fail, they cannot simply be left behind, or collisions will trigger a catastrophic runaway debris cascade—an L1 version of the Kessler syndrome. Finally, the carbon footprint of the launches themselves presents an ironic obstacle. Citing calculations by Tim Dodd (The Everyday Astronaut), Joe notes that a single SpaceX Starship launch would generate approximately 2,683 tons of $\text{CO}_2$. Multiplying that by the required 2.9 million Starship launches yields an astonishing 7.7 billion metric tons of $\text{CO}_2$ pumped directly into the atmosphere, leading Joe to observe:

> “Multiply that by 2.9 million and we're putting 7.7 billion metric tons of $\text{CO}_2$ into the atmosphere, which seems to kind of defeat the point.”

For perspective, that emission volume is comparable on an annual basis to the global commercial airline industry, which accounts for roughly 2.5% of total worldwide greenhouse gas emissions.

- **Global noble gas production:** ~6 metric tons/year for xenon; ~700,000 metric tons/year for argon. - **Estimated operational lifespan:** 20 to 30 years per shade before disposal is required. - **Starship emissions per launch:** 2,683 tons of $\text{CO}_2$. - **Cumulative launch emissions:** 7.7 billion metric tons across 2.9 million launches.

---

[19:05](https://www.youtube.com/watch?v=6yqi0FabHHs&t=1145s) Sci-Fi Workarounds: Railguns and the EmDrive

While Joe’s baseline calculations relied on technologies expected within the next five to ten years, Roger Angel’s proposal explored more radical, theoretical alternatives. Rather than relying entirely on chemical rockets, Angel proposed an electromagnetic railgun embedded into the side of a tall mountain or extending several miles upward to pierce the thickest layers of atmospheric resistance. Launching payloads every five minutes, this three-mile-high accelerator could impart the bulk of the escape velocity, requiring only minimal onboard propellant to nudge the payloads the rest of the way to L1.

On the shade side, another speculative concept involves replacing ion thrusters with propellantless propulsion, such as the controversial EmDrive. While experiments conducted by NASA’s Eagleworks showed anomalous thrust that was nearly indistinguishable from background air currents, an operational propellantless drive powered by onboard photovoltaic panels could theoretically keep shades stabilized indefinitely without consuming mass.

```mermaid flowchart TD accTitle: Earth vs Moon Space Shade Deployment Concepts accDescr: Comparison showing the Earth-based launch concept versus the lunar manufacturing and railgun deployment route.

subgraph EarthLaunch["Earth-Based Concept (Roger Angel)"] A["3-Mile-High Railgun / Starship"] --> B["Atmospheric Drag & High Fuel Burn"] B --> C["Onboard Ion Thrusters / EmDrive"] C --> D["Station-Keeping at L1"] end

subgraph MoonLaunch["Lunar Manufacturing Architecture"] E["Autonomous Lunar Factories"] --> F["Melt Regolith into Shades"] F --> G["Stack onto Pods (3 Weeks/Mo.)"] G --> H["Lunar Railgun Slingshot at L1 Approach"] H --> I["Deploy Shades & Reusable Pods Return"] end ```

---

[20:39](https://www.youtube.com/watch?v=6yqi0FabHHs&t=1239s) The Ultimate Hack: Autonomous Lunar Manufacturing

The most viable long-term architecture circumvents Earth entirely by relocating automated production to the Moon. Operating under lunar gravity (one-sixth of Earth's) drastically reduces the energy required for construction and launch. Furthermore, the Moon is already roughly a quarter of the way to L1, lacks an atmosphere to impose fairing constraints, and provides an orbital slingshot velocity that can be exploited during specific launch windows.

Joe outlines a hypothetical automated system where robotic factories on the far side of the Moon harvest lunar regolith, refine it into shade structures, and extract aluminum to construct control modules. Earth would only need to ship sophisticated components that cannot be manufactured locally, eliminating the need for 800 launches a day from Earth's surface. Over three weeks each month, the factories would assemble and stack shades into transport pods. During the fourth week—when the Moon's orbit brings it closest to aligning with L1—electromagnetic railguns would fire the pods into space without burning propellant. After releasing their cargo at L1, the pods would fire thrusters to fly back to the lunar base, land, refuel, and repeat the cycle in a continuous, 24/7 autonomous loop.

- **Gravity advantage:** Lunar gravity ($1/6\text{g}$) requires drastically less fuel to achieve escape velocity. - **Operational schedule:** 3 weeks of continuous factory manufacturing and pod assembly followed by 1 week of railgun launches timed with the Moon's orbital alignment toward L1. - **Logistical profile:** Fully reusable transport pods deploy shades at L1 and return to the Moon to reload.

---

[22:19](https://www.youtube.com/watch?v=6yqi0FabHHs&t=1339s) Economic Justification and the Opportunity Cost

Implementing such an infrastructure would demand unprecedented capital, raising the question of whether global civilization could ever afford it. Referencing a study by the Economist Intelligence Unit, Joe argues that humanity may not have a choice: climate-induced droughts, floods, crop failures, and supply-chain breakdowns are projected to cost the global economy upwards of $7.9 trillion by 2050. Spending money on mitigation directly injects capital into businesses, payrolls, and working households, rather than burning value on disaster relief. Just as with big planetary missions like Curiosity or Perseverance, money spent on space programs is not simply fired into the void; it circulates through industries, engineers, and local economies.

Even so, building a sunshade is a centuries-long engineering endeavor that acts merely as a temporary temperature band-aid. It does nothing to halt other consequences of greenhouse gases, such as ocean acidification. While spin-off technologies like autonomous robotics, AI, and lunar freight networks would transform human capability, banking on international unity remains historically unrealistic. Joe jokes about the idea of all nations, creeds, and ideologies coming together in selfless sacrifice, only to catch himself:

> “I'm sorry, I'm sorry, I forgot what year we're in.”

---

[24:17](https://www.youtube.com/watch?v=6yqi0FabHHs&t=1457s) Roger Angel’s Verdict: A Distraction from the Real Solution

Even Roger Angel concluded that sunshades should not be treated as a primary escape hatch. Diverting trillions of dollars to manufacture orbital umbrellas while continuing to pump fossil fuels into the atmosphere is fundamentally flawed. Quoting Angel's original paper, Joe highlights the author's own warning against treating geoengineering as a primary fix:

> “The same massive level of technology innovation and financial investment needed for the sunshade could, if also applied to renewable energy, surely yield better and permanent solutions.”

Reflecting on 2020 as a turbulent year of transition marked by the global pandemic, Joe acknowledges that climate change often slips from immediate focus when immediate emergencies dominate. However, rebuilding post-crisis economies presents an opportunity to overhaul the energy grid directly. Investing massive sums into clean terrestrial infrastructure accomplishes economic stimulus while simultaneously tackling emissions at the source—killing two birds with one stone, rather than relying on orbital science fiction.

[25:40](https://www.youtube.com/watch?v=6yqi0FabHHs&t=1540s) Finding Your Passion: Elle Luna and Skillshare

Wrapping up the climate and sunshade discussion, Joe playfully invites viewers to debate in the comments or “throw some shade” at him. Laughing off potential criticism, he explains that doing what he loves keeps him grounded: “I said throw some shade at me, and you know what, I can take it, you know why? Because I love making these videos—this is what I'm passionate about, that makes me immune to your hate.” For viewers looking to connect with their own drive, he recommends the Skillshare course *Choose Must: 10 Exercises to Find and Pursue Your Passion*, taught by artist, designer, and author Elle Luna.

Joe notes that Luna’s philosophy has influenced his channel for years, ever since he first learned about her book through Tim Ferriss. He explains that life often traps people in a web of obligations: “She talks about how we all have our shoulds in life—the things that we have to do to pay our bills and to keep things going and whatnot—but it also means that we kind of reject the other side of the coin, which is our must.” While the “shoulds” represent duty, the “must” represents the deeper calling that provides fulfillment and purpose. Luna’s class translates the concepts from her book into ten practical, step-by-step exercises to help students uncover and execute those goals.

Broadening out to the platform itself, Joe highlights Skillshare’s library of thousands of expert-led courses spanning graphic design, marketing, business essentials, video production, and cooking. He pitches a special promotion where the first 1,000 viewers to register using the link in the description receive two months of Skillshare Premium for free, followed by an ongoing subscription rate under $10 a month, which he calls a far smarter investment than many everyday purchases.

- **Featured Course**: *Choose Must: 10 Exercises to Find and Pursue Your Passion* by Elle Luna - **Key Concepts**: Balancing practical life obligations ("shoulds") against core creative and personal callings ("musts") - **Promotional Offer**: 2 free months of Skillshare Premium for the first 1,000 sign-ups, followed by a membership rate under $10/month

---

[27:44](https://www.youtube.com/watch?v=6yqi0FabHHs&t=1664s) Community Support and Channel Sign-Off

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## Notable quotes > [24:17](https://www.youtube.com/watch?v=6yqi0FabHHs&t=1457s) The same massive level of technology innovation and financial investment needed for the sunshade could, if also applied to renewable energy, surely yield better and permanent solutions. — Roger Angel

## Mentioned Joe Scott, Roger Angel, Ethan Siegel, Kimi Talvitie, Tim Dodd, Elle Luna, Tim Ferriss, John Thompson, Elon Musk, Skillshare, SpaceX, Starship, Saturn V, New Glenn, Space Launch System, James Webb Space Telescope, Starlink, Proceedings of the National Academy of Sciences, Starts With A Bang, Economist Intelligence Unit, NASA, Eagleworks, EmDrive, Curiosity, Perseverance, The Matrix, Patreon

## Video description The first 1000 people to sign up at https://skl.sh/joescott15 will get 2 free months of Skillshare Premium for free! Space shades are often touted as our last hope if our climate change situation gets too out of control. If we can't keep carbon emissions down, we could just block the sun. I hear this option get thrown out very casually, but I've never seen a realistic look at what that would look like. How big would it need to be? How much would it cost? Wound it even work? So I decided to take a serious deep dive.

Here's the link to the paper by professor Roger Angel: https://www.pnas.org/content/103/46/17184

Animations and shade designs by Kimi Talvitie: Find more of his work on Twitter: @kimitalvitie

Ethan Siegel's take on Starts With A Bang: https://medium.com/starts-with-a-bang/ask-ethan-can-we-build-a-sun-screen-to-combat-global-climate-change-c6399f279ef

Watch this video ad-free on Nebula: https://nebula.tv/videos/joe-scott-sun-shades-wont-save-us-from-climate-change

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[Source](https://www.youtube.com/watch?v=6yqi0FabHHs)

中文简报

星舰太空遮阳伞方案面临2千万亿美元天价成本与巨量碳排放 部署轨道遮阳伞星座以遏制全球变暖将导致世界经济破产并排放数十亿吨二氧化碳，相比之下直接投资地面清洁能源要切实得多。 乔·斯科特进行了一项详细的工程与经济思想实验，以探究在拉格朗日L1点部署遮阳伞阻挡2%的太阳辐射，是否真能扭转全球变暖。在计算出所需遮挡面积高达260万平方公里后，他指出若使用SpaceX的“星舰”部署该阵列，将需要近290万次发射，耗资数万亿乃至数千万亿美元，且仅发射阶段就会排放数十亿吨二氧化碳。在审视了自主月球制造和电磁轨道炮等推测性替代方案后，斯科特得出结论，将太空遮阳伞视为紧急退路是不切实际的干扰项；他认同罗杰·安吉尔的观点，即同样的资金和创新应直接投入到地面清洁能源领域。 在拉格朗日L1点仅阻挡2%的入射阳光即可抵消累积的全球变暖效应，但这需要大约260万平方公里的遮挡面积——相当于美国本土面积的约三分之一。 (5:01) 若在10年窗口期内利用SpaceX星舰从地球部署该遮阳屏障，将需要近290万次发射——约合每天发射719次——仅发射运营费用就高达数万亿美元。 (9:41) 制造预估所需的435亿个可控遮阳伞将耗资2.175千万亿至4.35千万亿美元以上，远远超过全球约81万亿美元的国内生产总值。 (11:18) 290万次星舰发射将直接向地球大气层注入约77亿公吨二氧化碳，从而在极大程度上抵消该遮阳伞带来的环境效益。 (16:59) 技术上更可行的替代方案涉及自主月球制造与电磁轨道炮，但研究员罗杰·安吉尔指出，将同等资金直接应用于地面可再生能源将带来更好且持久的效果。 (20:39)

Source quotes

[24:17] Roger Angel: The same massive level of technology innovation and financial investment needed for the sunshade could, if also applied to renewable energy, surely yield better and permanent solutions.

Original transcript

[0:00] this video is supported by skillshare [0:03] our electricity grid is getting greener [0:05] and cleaner every year [0:07] renewable energy is one of the top job [0:08] markets in the u.s and all around the [0:10] world [0:11] electric cars are finally getting taken [0:12] seriously by mainstream auto [0:13] manufacturers [0:15] these are glorious days my friend [0:18] glorious days [0:19] yeah hold up the problem is this [0:21] transition isn't happening nearly fast [0:23] enough to keep up with the growing [0:24] population around the world and [0:26] the increasing number of developing [0:28] nations that are industrializing around [0:29] the world [0:30] the amount of co2 we put in the [0:32] atmosphere breaks new records every [0:33] single year [0:34] and the predictions from climate [0:35] scientists continue to get more and more [0:37] dire [0:38] assuming things continue at this pace we [0:40] may reach a point of no return [0:42] a point where it's going to take [0:43] something really drastic to turn things [0:44] around [0:45] and among some of those drastic last [0:46] ditch ideas is the idea of putting a [0:49] giant solar shade in space to just [0:50] simply block the sun from hitting us or [0:52] at least block enough of it to return [0:54] our global temperatures to you know [0:55] pre-industrial levels [0:56] now i've heard about this idea i'm sure [0:58] many of you out there have heard about [0:59] this idea but [1:01] how would something like this work is it [1:03] even possible what would it cost and [1:05] maybe the biggest question [1:07] would it even fix the problem i've never [1:10] really seen this broken down [1:12] so i decided to give it a try so get [1:15] those slide rules ready because we're [1:16] about to map the [ __ ] out of this [1:20] [Music] [1:21] so when you talk about what makes the [1:22] planet warm there's a lot of variables [1:24] involved and it's a very [1:26] complicated system but if you want to be [1:27] reductionist about it you could really [1:29] break it down to just two things [1:30] the amount of heat entering the system [1:32] from the sun and the ability the [1:33] atmosphere to trap that heat and prevent [1:35] it from escaping [1:36] now obviously the better option is to [1:37] regulate the atmosphere so it's trapping [1:39] the right amount of heat but if let's [1:40] just say things go a little bit too far [1:42] and we can't do that [1:44] or aren't willing to do that then the [1:46] other option is to reduce the amount of [1:47] heat entering the system so that's what [1:49] we're talking about here today you know [1:50] how do we do [1:51] that but before we get to the main event [1:53] let's talk about an option that's a [1:54] little bit more down to earth [1:55] so one way to go about it would be to [1:57] seed clouds up in the upper atmosphere [2:00] these are white they're reflective they [2:02] have a higher albedo and they can [2:03] prevent a lot of the heat from actually [2:04] reaching the surface [2:05] but clouds are not very long-lived [2:07] though and we would constantly be trying [2:08] to replenish them with thousands of jets [2:11] flying into the air all the time [2:12] adding more co2 to the atmosphere it [2:15] kind of seems like it defeats the [2:16] purpose [2:17] now others have suggested kind of [2:18] sprinkling reflective dust [2:20] up into the stratosphere and we know [2:22] that something like that might work [2:24] because we've seen it work in 1991. on [2:27] june 15th of that year [2:28] mount pinatubo erupted in the [2:29] philippines injecting 15 million tons of [2:32] sulfur dioxide into the stratosphere [2:34] where the winds dispersed the haze all [2:35] around the world [2:36] and the effect was that over the next [2:37] year global temperatures actually [2:39] dropped by one degree [2:41] now we've seen this before in the mount [2:42] tambora eruption which i've talked about [2:44] before it actually created what they [2:45] called the the year without a summer [2:47] it dropped the temperatures that much [2:48] but this was the first time that it [2:50] happened at a time when we had [2:51] satellites up in the sky [2:53] able to actually monitor and measure [2:54] this at a very you know detailed level [2:56] so doing the aerosol thing with balloons [2:58] up in the stratosphere [3:00] is an option but we're still talking [3:02] about a massive operation here we're [3:03] talking about 15 million tons [3:05] of stuff we're putting up into the [3:07] atmosphere and [3:09] there's still a lot of unintended [3:11] consequences that we don't know about [3:12] there's still a lot of room for things [3:13] to go wrong there [3:15] now these fall into the category of [3:16] geoengineering and the problem with [3:18] these is that it's not [3:20] really reversible if you don't 100 know [3:22] what the consequences of this are going [3:24] to be [3:24] and there is no way to know that because [3:26] you've never done it before then [3:28] you're kind of stuck with it if you [3:29] remember it wasn't the machines that [3:31] blacked out the sky in the matrix [3:33] so there are some good reasons for [3:34] building a massive solar shade in space [3:37] as opposed to doing the geoengineering [3:38] thing there are some good arguments for [3:40] the geoengineering thing as well but for [3:42] our purposes let's just say we have 10 [3:44] years to do this [3:45] and it all comes down to us building [3:47] this shade we all got to come together [3:49] and do that here's what that would look [3:51] like all right so the first thing you [3:52] need to figure out is how big does this [3:54] thing need to be [3:56] actually no the first thing you need to [3:57] figure out is where you're going to put [3:59] this because deciding where it's going [4:00] to go [4:01] will determine how big that it needs to [4:03] be so where between the sun and the [4:05] earth [4:05] could you put a thing like this and i [4:07] know that before i even finished that [4:08] sentence a lot of you out there were [4:10] like [4:10] l1 and if you are one of those people [4:13] huh [4:14] i mean you and i we're like i mean [4:18] that's weird and if you don't know what [4:20] l1 is well [4:22] you must be new here and let me be the [4:24] first to say welcome thank you for [4:25] checking out my channel [4:26] i'm glad to have you here and to get you [4:28] caught up on why everybody else was [4:30] saying [4:31] l1 and not you is because l1 stands for [4:34] lagrange point one and lagrange points [4:36] are areas around the earth or any [4:38] orbiting body for that matter [4:39] where the gravity of the earth and the [4:40] gravity of the sun kind of even each [4:42] other out [4:43] and the grange points are stable so if [4:45] you put something out into a lagrange [4:46] point it will pretty much stay there [4:48] relative to the earth [4:50] there are five lagrange points [4:51] designated l1 through l5 and l1 is the [4:53] one between the earth and the sun l2 is [4:56] on the opposite side of the earth kind [4:57] of lined up with the sun and this is [4:59] actually where the james webb space [5:00] telescope is going to go [5:01] all right so now that we know where it's [5:02] going how big does this need to be well [5:04] the good news is you only have to block [5:06] two percent to [5:07] offset the amount of rise that we've [5:09] seen and get things back to sort of a [5:10] pre-industrial level [5:11] and by the way i got this in most of the [5:14] stuff from this video actually from a [5:15] couple of different sources one is ethan [5:17] siegel's blog starts with a bang [5:19] which i highly recommend it's great and [5:21] the other is from a 2006 paper [5:22] from professor roger angel and where he [5:26] actually took a total feasibility study [5:28] of this entire idea [5:30] and it's really interesting goes really [5:31] detailed i'll put a link to it down in [5:33] the description if you want to go check [5:34] it out [5:34] so yeah two percent but we have to know [5:37] what 100 is so we can calculate what the [5:39] two percent is like two percent of what [5:41] exactly so what is a hundred percent [5:43] coverage well a shade with the same [5:45] diameter as earth would be twelve [5:46] thousand seven hundred and forty two [5:48] kilometers [5:48] but a shade at l1 would need to be just [5:51] slightly bigger [5:52] because the sun is way bigger than the [5:54] earth making the light that hits the [5:55] earth sort of a cone with the earth and [5:57] the small end of it [5:58] so l1 which is 1.5 million kilometers up [6:00] the cone [6:01] would be at a slightly larger segment of [6:03] cone so it would need to be bigger [6:05] now the distance from the earth to the [6:06] sun is 149.6 million kilometers so l1 is [6:10] about one percent of the total distance [6:12] so let's raise the size about one [6:13] percent which will get us to a diameter [6:15] of 12 [6:16] 869 kilometers it seems like a lot of [6:18] explanation for [6:19] not much difference all right so we have [6:21] the diameter now let's figure out the [6:23] area that we need to cover and for that [6:24] we just apply a little pi r squared [6:26] and that comes out to 129 million 984 [6:30] 558 square kilometers luckily we only [6:33] have to cover about two percent of that [6:34] which puts us at two million five [6:36] hundred ninety nine thousand six hundred [6:37] and ninety one square kilometers [6:39] and for the sake of my laziness and for [6:41] easier spitballing i will be rounding [6:42] this video so let's just say the magic [6:44] number is 2.6 million kilometers squared [6:47] so what does 2.6 million square [6:48] kilometers look like you may be asking [6:51] especially if you're an american well it [6:52] comes out to almost exactly the combined [6:54] areas of the states of washington [6:56] oregon california nevada utah idaho [6:59] arizona montana and wyoming [7:03] about a third of the continental united [7:04] states so yeah not only do we need to [7:06] build something that could completely [7:08] cover [7:09] that we need to launch that into space [7:14] i think this qualifies as a mega project [7:16] and this is where you pound your fist on [7:17] the desk and you say we're not gonna [7:18] launch it all at once [ __ ] [7:22] i know calm down the question is what do [7:25] you do with it when you get to l1 do you [7:26] assemble it into one giant shade do you [7:28] have sort of a free-flowing [7:31] swarm of shades or do you have like a [7:33] cloud of micro shades [7:34] now each has their advantages the solid [7:36] structure might be the easiest to [7:37] control because it is only one [7:39] monolithic device and this does [7:40] matter because lagrange points aren't [7:42] really stable they're stable-ish [7:44] so whatever we put up there will [7:46] constantly be fighting against the [7:47] various forces at play there [7:48] now the downside of one giant shade is [7:50] that you know some errant piece of space [7:52] debris were to fly through and hit it it [7:54] would knock the whole thing out you know [7:55] there's [7:56] there's no redundancy there and plus [7:58] every single time you dock one of those [8:00] pieces together that's another [8:01] opportunity for something to go wrong [8:03] and screw the whole thing up [8:04] all of those problems can be fixed with [8:06] a swarm of shades of course the danger [8:07] there is that there's more chances for [8:09] collisions between shades if one of them [8:10] goes offline and loses guidance [8:12] and then there's the idea of just [8:14] dumping off a cloud of either micro [8:16] shades or even just dust and debris to [8:18] create a haze [8:19] to block the light of course that's not [8:20] particularly better than the [8:21] geoengineering idea it's permanent and [8:24] there's nothing you can do about you [8:25] know any unintended consequences that [8:27] come from that [8:27] so yeah the mid-size shades with some [8:29] kind of guidance unit attached to it [8:30] kind of wins out for me i think it's [8:32] sort of the best of both worlds [8:34] you know if you needed to adjust the [8:36] light and let more light in for some [8:37] reason all you have to do is just turn [8:38] it sideways [8:39] and that lets more light in so you know [8:41] hey take that unintended consequences [8:44] so now you have to ask how big each of [8:45] these shades would be one option would [8:47] be to make them as big as possible by [8:49] performing some miracle of origami to [8:51] unfurl once it gets there kind of like [8:52] we do with [8:53] you know solar panels on satellites but [8:55] that adds complexity [8:56] more opportunities for things to go [8:57] wrong and it adds extra hardware and [8:59] weight [9:00] ultimately it's all about surface area [9:01] and getting as much surface area to l1 [9:03] per launch as possible so we're looking [9:05] for something [9:05] simple inexpensive and will fit inside [9:07] of a payload fairing [9:09] and we're going to need the biggest [9:10] payload fairing possible and in the next [9:12] five years or so [9:14] barring any disasters easily the biggest [9:16] one will be the spacex starship [9:18] starship's fairing will be a massive 9 [9:20] meters wide and 18 meters tall [9:22] even the saturn 5's payload was 6.6 [9:25] meters which is about what the new glenn [9:26] is expected to have [9:27] now the sls block 2 cargo vehicle should [9:30] have an 8.4 meter fairing and there are [9:32] designs and concepts that could get it [9:33] up to 10 [9:34] but i'd argue that the starship is [9:35] really the only way to do this you would [9:37] have to have a fully reusable vehicle [9:38] and starship's the only vehicle [9:39] literally ever built that could do that [9:41] so let's just say we got these super [9:44] thin down to like a millimeter thin [9:45] which is [9:46] insane especially considering it's going [9:48] to need to be about 8.75 meters wide to [9:51] allow a little bit of room for the [9:52] guidance and control modules that are [9:53] attached to them [9:54] so let's say we're able to do that and [9:56] we can just stack them up inside of a [9:57] starship fairing [9:58] how many could we fit in there by the [10:00] way this is how big that shade would be [10:02] standing next to an average sized person [10:04] well we'll have to allow for a small [10:05] kick stage to actually get these shades [10:07] out to l1 which again [10:09] is 1.5 million kilometers away so we're [10:11] not going to be sending the starship all [10:12] the way out there [10:13] so i'm guessing maybe about three meters [10:15] for that give or take a little bit [10:17] so that would leave about 15 meters of [10:18] stacking space which if our shades are [10:20] one millimeter thick [10:21] would come out to about 15 000 shades [10:23] per starship launch [10:24] doing a little bit of math an 8.75 meter [10:26] diameter circle would come out to just [10:28] about 60 square meters per shade at 15 [10:31] 000 per starship [10:32] and you get that each starship could put [10:33] 900 000 square meters of shades up at a [10:36] time [10:36] that's 0.9 square kilometers so how many [10:39] launches would it take to cover the full [10:40] 2.6 million square kilometers needed to [10:42] reduce the sun's energy by 2 percent [10:44] we'll divide 2.6 million by 0.9 and you [10:47] get 2 [10:48] 888 888 launches [10:51] if we were to launch a fully loaded [10:52] starship every single day that would [10:54] take 7914 years [11:00] yeah i was hoping for closer to 10 years [11:03] if we were to get this shade up in 10 [11:04] years [11:05] that would be 719 launches a day [11:08] a launch every two minutes every day [11:12] for 10 years clearly we have already [11:15] entered the realm of absurd with this [11:17] idea so let's just keep going and ask [11:19] how much something like this would cost [11:20] now there are a lot of ways to calculate [11:22] this like cost per kilogram of launch [11:23] but just to make things simple in [11:25] november of 2019 elon said at a chat [11:27] with air force lieutenant general john [11:28] thompson that starship could operate for [11:30] as low as two million dollars per launch [11:32] so if we were to go off that figure and [11:34] i will because it's [11:35] a big nice round number and easy to work [11:37] with that would come out to 5.8 trillion [11:40] dollars [11:41] and that's just for the launches to get [11:43] out there and that doesn't even factor [11:44] in that kick stage that i was talking [11:45] about so i think i'm actually being [11:47] pretty generous here [11:48] and that's just the cost of getting them [11:49] up there what's the actual cost of [11:52] making these shades [11:53] well i did a little bit of googling and [11:55] the spacex starling satellites that [11:57] they're already producing in mass those [11:58] are around 250 000 [12:00] per satellite so in some ways these [12:02] shades would be simpler than the [12:03] starlink satellites but in other ways [12:05] they won't be [12:06] l1 is really far out there there is no [12:08] way we'll be able to service them so [12:09] they'll have to be fully autonomous [12:11] plus they'll need to be able to [12:12] communicate over that distance and with [12:14] each other [12:15] so just to once again be generous and [12:16] have an easy round number to work with [12:18] why don't we make it i don't know [12:19] a hundred thousand a shade maybe [12:22] something like that [12:23] all right math time if it's around 15 [12:25] 000 shades per launch and we're doing [12:27] roughly 2.9 million launches that's 43.5 [12:30] billion [12:31] shades at 100 000 per shade well that's [12:34] 4.35 quadrillion dollars [12:40] you know what i didn't i didn't factor [12:41] in economies of scale so let's just [12:43] let's just take it half that let's say [12:44] it's 50 000. how about that yeah so that [12:46] would take it down to 2.175 [12:49] quadrillion dollars so yeah that's that [12:52] that that's [12:53] that's much more reasonable [12:57] yeah so i i couldn't help myself so i [13:00] actually stacked up some dollar bills to [13:02] see [13:02] how many per millimeter and it came out [13:04] to about five per millimeter and it [13:06] turns out if you stack up [13:07] 2.175 quadrillion dollars [13:12] it would reach the lagrange point [13:15] 290 times yeah a stack of that much [13:19] money would stretch 435 million [13:21] kilometers [13:22] that's far enough to reach the sun [13:26] and then keep going and hit the earth's [13:27] orbit on the other side of the sun [13:30] and then hit mars this is not just an [13:34] insane amount of money it's actually 26 [13:37] times the global gdp of 81 trillion [13:39] dollars [13:40] okay so there's literally not enough [13:42] money in the world to do this [13:44] but are there even enough resources i [13:47] mean we have to cover an area the size [13:48] of two columbias [13:50] whatever we make this out of has to be [13:51] super cheap super abundant [13:54] very strong so you can cut it into very [13:56] thin slices [13:57] and if possible a little bit transparent [14:01] so transparent might be a weird [14:03] requirement for a shade but according to [14:05] that paper by roger angel [14:07] these shades would be constantly [14:08] bombarded by solar wind that's [14:10] energetic particles as well as photons [14:12] and it would be constantly fighting [14:14] against that unless it was dispersing [14:17] the photons as opposed to just taking [14:19] all the force themselves [14:20] so there are various ideas around that [14:22] one is to have [14:23] sails with tiny little pores in it they [14:25] can kind of let just a little bit of it [14:27] through one might be to have [14:29] slats that kind of deflect the light at [14:31] a certain angle and one is to just [14:33] create that of a type of glass that can [14:34] just sort of diffuse the light more than [14:36] shade it [14:37] a glass isn't the worst idea because it [14:39] is made out of very abundant materials [14:40] and it's somewhat [14:41] cheap the problem is creating an 8.75 [14:44] meter [14:45] plate of glass that's only one [14:46] millimeter thick that's strong enough to [14:48] survive launch it might have to be some [14:50] kind of advanced gorilla glass [14:52] technology or something like that [14:53] by the way there is a version of this [14:55] idea that doesn't block the sun at all [14:57] but actually [14:58] creates sort of a fresnel lens and this [15:00] would simply spread the light around [15:02] in various angles around the earth so [15:03] just less light is hitting us [15:05] now since they aren't totally blocking [15:07] the light you might have to cover more [15:08] area out there in order to fuse enough [15:09] light to make a difference [15:11] but that is an idea that's been floated [15:13] around now i also did read about the [15:14] possibility of some materials that could [15:16] absorb the light on one side and emit it [15:18] as heat [15:19] out the other side that would kind of [15:20] push back and keep it in a bit of an [15:23] equilibrium there [15:24] but whatever these materials we're going [15:25] to need to have a lot of it [15:27] like one kazakhstan worth and most [15:30] likely it's something we would want to [15:31] mine from the sea floor so that we're [15:32] not you know destroying copious amounts [15:34] of land that people are actually living [15:35] and farming on [15:36] plus there's a transportation of that [15:38] material to the factories building the [15:39] shades which oh by the way [15:41] holy crap so many factories [15:44] i used that 10-year timeline earlier [15:46] saying that it would take 791 launches a [15:48] day well each one of those launches [15:50] would carry 15 [15:51] 000 shades in it which would mean that [15:53] the factories around the world making [15:54] these shades would need to make 11 [15:56] million [15:57] 866 000 every single day [16:00] and once again i would like to point out [16:01] that each one of these shades would be [16:02] this big [16:04] i mean how do you even get that to the [16:06] rocket facility chances are you'd need [16:08] to build the factories really close to [16:09] the launch center so it'd be easier [16:11] to get them on the rockets or more [16:13] likely you would have to fully construct [16:15] construction [16:16] and launch facilities together for that [16:18] one singular purpose [16:20] and hundreds of them around the world so [16:25] at this point it seems pretty obvious [16:26] that the whole 10-year timeline that [16:28] i've been sticking to [16:29] is ridiculous and impossible if this [16:31] were to happen it would be a [16:32] multi-generational project [16:35] least a hundred years so the reason i've [16:37] been using this arbitrary 10-year [16:39] you know timeline here is because every [16:41] single time people talk about this idea [16:43] it's sort of like a last-ditch effort [16:45] it's the thing that you do when [16:46] everything else has failed and our [16:48] entire existence hangs in the balance [16:50] in that situation you're not going to [16:52] have hundreds of years to play with [16:54] i mean we don't even right now have [16:55] hundreds of years to play with that the [16:57] worst projections are true [16:58] so there's literally not enough money in [16:59] the world to pay for these things [17:01] gathering the resources would be [17:02] horribly destructive to our [17:04] planet and then there's the energy [17:05] required to build [17:07] all of this in the first place and on [17:09] top of all that [17:10] we may literally not have enough fuel [17:12] for the shades themselves [17:13] the shades will need to be able to [17:15] stabilize themselves up there with [17:16] control thrusters of some [17:18] kind and that's going to require some [17:19] kind of fuel something super efficient [17:22] that can last a long time [17:23] tiny ion drives might be the way to go [17:26] because they are super efficient and [17:27] produce only a tiny amount of thrust but [17:29] that might be enough to you know allow [17:30] some kind of stability and whatnot [17:32] but even those run on argon or xenon and [17:35] we only produce six metric tons [17:37] of xenon every year so that seems to be [17:40] out of the question [17:41] there's 700 000 metric tons that we [17:43] produce of argon every year [17:45] but we also use that for other things so [17:47] maybe if we used all of it there [17:49] might be enough i don't know this one is [17:51] still a bit of a question mark for me to [17:52] be honest you guys can talk about this [17:54] one in the comments [17:55] and another issue with the shades is [17:56] what do we do with them when they cease [17:58] to be operational [17:59] they are all going to have some kind of [18:01] limited life span roger angel said maybe [18:03] 20 to 30 years [18:04] so eventually when they do go down we're [18:07] gonna have to be able to get them out of [18:08] l1 or else they'll start crashing into [18:10] into each other and we'll have sort of [18:11] an l1 kessler syndrome going on [18:14] and last but not least 2.9 million [18:17] starship launches [18:19] that is a lot of burn methane my buddy [18:21] tim dodd did a video about this and he [18:23] figured out that a starship would [18:24] produce about 2683 tons of co2 [18:28] per launch which yikes [18:32] multiply that by 2.9 million and we're [18:34] putting 7.7 [18:35] billion metric tons of co2 into the [18:37] atmosphere [18:40] which seems to kind of defeat the point [18:42] and just for context [18:43] and to maybe make you cry a little bit [18:46] that [18:46] on a yearly basis is pretty close to the [18:48] same amount that the [18:49] airline industry produces and they only [18:52] produce 2.5 percent [18:54] of global emissions so [18:58] that's why we have to talk about [18:59] building a sun shade in the first place [19:05] so this whole video i've been trying to [19:06] stick with current technologies or at [19:08] least technologies that will be [19:09] available in the next five to ten years [19:11] like the starship [19:12] but roger angel who wrote the paper that [19:14] i keep referring back to [19:16] um he did no such thing there are [19:18] theoretical future technologies that [19:20] could help make this [19:21] a little more doable for example in his [19:23] paper he talked about building a giant [19:25] electromagnetic rail gun [19:27] that could just fire this stuff out in [19:29] the atmosphere [19:30] he suggested this could be built into [19:31] the side of a tall mountain or just [19:33] built tall enough that it could get [19:34] outside of the [19:35] atmospheric resistance that we would [19:37] encounter with a regular launch but [19:39] that would put it on its way toward l1 [19:40] with maybe only just a little bit of [19:42] propellant needed [19:42] to get it the rest of the way there he [19:44] suggested a railgun would be able to [19:46] launch [19:46] literally every five minutes and it [19:48] would be cheaper [19:49] outside the cost of building you know a [19:51] three mile high gun [19:53] now another theoretical idea that might [19:55] help push this thing along and [19:57] don't laugh too much here would be some [19:59] kind of electromagnetic drive or [20:02] m drive for the shades themselves [20:04] instead of the ion thrusters [20:05] i've covered m drives before it's super [20:08] debatable whether or not these things [20:09] produce any thrust at all but if they do [20:12] they don't require any propellant it [20:14] would just require electricity which you [20:15] could easily get by putting a little pv [20:17] panel on these shades technically they [20:19] could run forever [20:21] so nasa's eagle works has been [20:22] experimenting with this idea for a while [20:24] but [20:24] if it's able to produce any thrust at [20:26] all it's almost indistinguishable from [20:28] the movement of air in a still room [20:31] so it's still got a long ways to go but [20:33] it doesn't need to produce [20:35] that much thrust to just you know give [20:36] it a little bit of adjustment out there [20:38] in space [20:39] but perhaps the ultimate hack to this [20:40] problem would be to have all the [20:41] manufacturing and all those factories i [20:43] was talking about [20:44] be done by autonomous robots and then [20:47] move those factories [20:49] to the moon there are so many advantages [20:51] to doing this on the moon just for [20:53] starters the low gravity makes the [20:54] construction way less energy intensive [20:56] which means you burn way less fuel to [20:58] leave the surface and reach out one [21:00] and besides it's less distance to cover [21:02] you're already a quarter of the way [21:03] there [21:03] not to mention you can use the momentum [21:05] from the moon's orbit to slingshot the [21:07] shades out to l1 as it swings around [21:09] and they can be any size you want you're [21:11] not limited to aerodynamic rocket [21:13] fairings you don't technically need any [21:14] fairings at all [21:15] and again with 1 6 gravity you can [21:17] launch way more of them at a time [21:19] so imagine there are autonomous [21:20] factories in the far side of the moon [21:22] digging up regolith melting it into [21:24] shades and assembling the control [21:25] modules from aluminum and the regolith [21:27] now regular launches of supplies from [21:28] earth would still need to be taken up to [21:30] the moon [21:31] you know for all the stuff that you [21:32] can't make on the moon but it wouldn't [21:34] be 800 launches a day [21:35] these factories stack them onto pods [21:37] three weeks out of the month and then in [21:39] the week that the moon is approaching l1 [21:40] in its orbit [21:41] the pods are shot towards l1 on hundreds [21:44] of rail guns using no propellant to get [21:45] them out of the moon's gravity well [21:47] the pods cruise out to the l1 drop off [21:49] the shades and then use thrusters to [21:51] head back to the moon and land [21:53] refuel and the process repeats itself [21:55] this can be running 24 7 with minimal [21:57] human involvement it's scalable it uses [21:59] a lot less earth resources [22:01] this is set it and forget it we're [22:03] really not that far away from being able [22:05] to do this [22:07] i mean i could go on about the current [22:08] state of autonomous robots and moon [22:10] missions and rail guns and alternative [22:12] propulsions and [22:13] i don't know maybe i will someday but [22:15] suffice to say we're already in the baby [22:17] steps of a lot of this stuff [22:19] but to get to where anything like this [22:20] could possibly be feasible would require [22:22] a massive amount of investment and the [22:24] question becomes can we afford it [22:27] well according to a study last year from [22:28] the economist intelligence unit [22:31] we might not be able to afford not to [22:33] they calculated that climate change [22:34] could cost the world economy 7.9 [22:36] trillion dollars by 2050 due to [22:38] flooding and droughts and famines and [22:41] breakdowns of supply chains [22:42] so if we're gonna have to spend that [22:43] money anyway we might as well spend it [22:45] on something that could mitigate the [22:46] problem something that would actually go [22:48] into the hands of families and companies [22:50] it's like every time there's a really [22:51] expensive space probe that goes up [22:53] something like curiosity or now [22:55] perseverance [22:56] you always hear people that look at the [22:58] price tag and they say they spent all [22:59] that money and just launched it into [23:00] space [23:01] but it's not like they just filled a [23:02] rocket with money and launched it into [23:04] space [23:05] all that money went to companies that [23:07] paid people and those people [23:08] used that money to provide for their [23:09] families and spent that to other [23:11] companies [23:11] that money goes into the economy so is [23:14] the giant space shade the best use of [23:15] that money [23:17] well there's clearly some massive [23:18] technological hurdles we had to overcome [23:20] it would take decades of [23:22] advancement and technology to be able to [23:23] even make this a viable option and even [23:26] then it would take hundreds of years to [23:27] build [23:28] and still it's just a band-aid it still [23:30] doesn't solve some of the other problems [23:31] caused by [23:32] proliferation of co2 in the atmosphere [23:33] like ocean acidification [23:35] now on the plus side all the investment [23:36] and technologies required to make this [23:38] happen would pay off in ways that we [23:40] can't even imagine now [23:41] things like an earth to moon [23:42] infrastructure autonomous robots [23:44] artificial intelligence advanced [23:46] propulsion technologies [23:48] all of this would be world changing [23:50] besides a big project like this could [23:52] could galvanize people you know it could [23:53] bring everyone together all [23:55] ideologies all nationalities all creeds [23:58] all colors [23:59] coming together in a spirit of [24:00] cooperation and sacrifice [24:06] i'm sorry i'm sorry i forgot what year [24:09] we're in [24:10] [Applause] [24:11] [Laughter] [24:17] look this is a crazy idea and just a lot [24:19] of fun spitballing here and i [24:21] implore you to continue the balling of [24:23] spit down in the comments below but even [24:25] as roger angel the guy who [24:27] wrote this paper said this is not the [24:29] easy fix to all of our problems [24:31] in the paper he wrote it would make no [24:33] sense to plan on building and [24:34] replenishing ever larger space sun [24:36] shades to counter continuing and [24:37] increasing use of fossil fuel [24:39] the same massive level of technology [24:41] innovation and financial investment [24:42] needed for the sun shade could [24:44] if also applied to renewable energy [24:46] surely yield better and permanent [24:47] solutions [24:49] a number of technologies hold great [24:50] promise given appropriate investment [24:52] now as i've said before this is a year [24:54] of transition [24:55] and with everything going on right now [24:56] with the pandemic and whatnot [24:58] climate change might not be top of mind [25:00] for most people [25:01] it's understandable one crisis at a time [25:05] but as we come out of this dumpster fire [25:06] of the year hopefully with [25:08] you know more of an eye toward changing [25:10] up our systems and our infrastructures [25:11] maybe this kind of investment in a [25:14] cleaner grid might be the thing that [25:16] with the kick in the pants to get the [25:17] economy started again you know [25:19] kill two birds with one stone those poor [25:21] birds [25:22] now i made a ton of assumptions in this [25:25] video there's a lot of different ways to [25:26] calculate and sort of [25:28] look at all this stuff i invite you guys [25:30] to spitball your brains out down in the [25:32] comments below [25:33] point out anything i might have missed [25:34] point out anything i might have gotten [25:36] wrong any ideas that you've heard that [25:38] would factor into this whole equation [25:40] talk it up amongst yourselves down below [25:42] or if you like you can just [25:43] throw some shade at me [25:44] [Applause] [25:48] i said throw some shade at me [25:53] and you know what i can take it you know [25:55] why because i love making these videos [25:57] this is what i'm passionate about that [25:59] makes me [25:59] immune to your hate but if you want to [26:02] find a way to tap into your passion i [26:03] can highly recommend the class [26:05] choose must 10 exercises to find and [26:07] pursue your passion [26:08] on skillshare this class is presented by [26:11] elle luna an artist designer and author [26:12] who speaks around the world on the [26:14] process of creativity [26:15] and self-actualization in this class she [26:17] breaks down 10 exercises and [26:19] tactical practices to guide you on a [26:21] journey of self-exploration to find what [26:23] she calls your [26:24] must the thing that drives you and gives [26:26] you purpose in life [26:27] and by the way you might not know this [26:28] but elle's work has been a part of this [26:30] channel for a very long time because [26:34] this is her book she talks about how we [26:36] all have our shoulds in life the [26:38] the things that we have to do to pay our [26:39] bills and to keep things going and [26:41] whatnot but it also means that we kind [26:43] of reject the other side of the coin [26:44] which is our must [26:45] our must being the thing that that [26:47] drives us and gives us passion and it [26:49] gives us purpose [26:50] i first heard about this book from tim [26:52] ferriss and it's a real kick in the [26:54] pants it's very inspirational and [26:56] this class is basically in this book in [26:58] video form and it gives you 10 very [27:00] tangible exercises that you can go [27:02] through [27:02] to help find and implement the [27:04] strategies in this book [27:05] now it's it's really inspiring stuff i [27:07] love this book i love this class [27:09] it's time well spent this is of course [27:11] just one of thousands of classes on [27:12] skillshare covering everything from [27:14] business essentials [27:15] graphic design marketing video [27:17] production cooking anything you're [27:18] interested in there's an expert ready to [27:20] teach it to you on skillshare [27:21] so join the millions of students already [27:23] learning on skillshare today if you're [27:24] one of the first 1 000 people to sign up [27:26] at the link in the description below you [27:28] can get unlimited access to thousands of [27:29] classes completely free [27:31] for two months and after that it's less [27:33] than ten dollars a month that's a very [27:34] smart use of ten dollars [27:36] you could spend it on way dumber things [27:38] anyway if you haven't checked out [27:39] skillshare already [27:40] please do check it out links down in the [27:41] description big thanks to skillshare for [27:43] supporting this video and a huge shout [27:44] out to the answer files on patreon that [27:46] are [27:47] building a community supporting the [27:48] channel and just being generally overall [27:50] awesome people i got some new people [27:52] that have joined gotta murder their [27:54] names real quick we've got [27:55] libby holtmann lauren newman jackie [27:57] donnelly theodore wilson [27:59] john pennington the third donald c klein [28:02] peter pernu pernu i think i've said your [28:05] name wrong before [28:06] uh dean mcmanus the ratty show lance [28:08] faye alicia herberter [28:10] chris leon joe in a box uh jonathan paul [28:13] kerry silko and jared danielson [28:15] thank you guys so much if you would like [28:16] to join them get early access to videos [28:19] and just access to me [28:20] and just be part of an awesome community [28:21] you can go to patreon.com [28:23] answers with joe please do like and [28:24] share this video if you liked it if this [28:26] is your first time here [28:27] google thinks you'll like this video as [28:29] well so give her a look [28:31] and if you do like that you can check [28:33] out any of the others and if you like [28:34] what i do [28:35] i invite you to subscribe come back with [28:37] videos every monday all right that's it [28:38] for now you guys go out there have an [28:40] eyeopening week be [28:41] safe and i'll see you next monday love [28:43] you guys take care