Computing Beyond the Grid — Orbital, Underwater, and Alternative Data Centres Explained

Terrestrial data centre expansion is running into a wall. US data centres now consume 4.4% of national electricity. Grid interconnection queues in Northern Virginia stretch past a decade, and community opposition to gigawatt-scale hyperscaler campuses has made that timeline worse. AI power demand is on a trajectory that outpaces everything utilities are planning to build. That wall is why, in the first 90 days of 2026 alone, eight organisations filed plans, launched hardware, or committed major funding to compute environments outside the terrestrial grid — orbital nodes on low Earth orbit (LEO) satellites, sealed pressure vessels on the ocean floor, and remote edge installations.

This hub maps the full territory. It links to seven in-depth cluster articles covering each facet of the alternative data centre landscape. The orbital market is projected to reach $39B by 2035 at 67% CAGR; the underwater market is growing from $3.2B in 2025 toward $14.8B by 2034. Neither figure tells you whether any of this matters for your infrastructure planning yet — that is what the articles are here to answer.

Use the table below to go straight to the topic you need, or read through each section for a full map of the territory.

What are alternative data centres and why are orbital, underwater, and edge locations emerging together now?

Alternative data centres (ADCs) are computing facilities deployed outside the conventional terrestrial power grid — orbital nodes on LEO satellites, sealed pressure vessels on the ocean floor, and remote edge installations. They are converging in 2026 because the constraint is the same for all three: grid capacity cannot keep pace with AI power demand, and community opposition to new on-grid construction has extended interconnection timelines to a decade or more in major US markets. Orbital compute exploits near-continuous solar energy and vacuum cooling; underwater compute exploits passive seawater heat exchange.

The cooling physics that make both environments viable are covered in the physics of alternative data centre cooling.

What is actually operational in orbit today?

Two commercial orbital data centre nodes are operational, deployed by Axiom Space to the ISS on 11 January 2026 — kW-scale edge nodes running cloud computing, AI/ML inference, data fusion, and cybersecurity workloads on commercial off-the-shelf (COTS) hardware. Starcloud launched its first satellite in November 2025: a 60 kg spacecraft with a single NVIDIA H100 GPU, the first to train a large language model entirely in orbit. Deloitte’s Project Constellation followed in March 2026.

The ISS nodes manage tens of kilowatts. An AI data centre needs megawatts. That gap is the primary engineering constraint of the field.

The full account of what Axiom Space deployed and what ran on it is in Axiom Space Orbital Data Centre Nodes — The First Commercial Launch in January 2026.

What is SpaceX’s orbital compute plan and how ambitious is it?

SpaceX filed FCC application SAT-LOA-20260108-00016 in January 2026 for a constellation of up to one million satellites with onboard AI compute capability. In May 2026, Anthropic signed an agreement expressing interest in multiple gigawatts of orbital AI capacity — the first AI-native company to signal hyperscale ODC demand. SpaceX’s own S-1 risk disclosures describe “significant technical complexity and unproven technologies” and note that orbital compute “may not achieve commercial viability.” SpaceX is not alone in this race: Blue Origin has filed for a 50,000+ satellite constellation (Project Sunrise), and Google’s Project Suncatcher is targeting a TPU-equipped demonstration by early 2027.

The Anthropic agreement is the most significant commercial signal to date, but it sits alongside SpaceX’s own frank acknowledgement that the million-satellite ambition has no precedent at this scale. For regulatory and competitive depth, the full analysis of SpaceX’s million-satellite FCC filing covers the filing, S-1 disclosures, and what the Anthropic deal actually commits.

The full regulatory and competitive analysis of the filing is in SpaceX and the Million-Satellite FCC Filing.

What hardware is designed for orbital AI workloads?

NVIDIA announced its Space Computing product line at GTC in March 2026: the Jetson Orin (available now, SWaP-constrained edge), the IGX Thor (Blackwell architecture, available now), and the Space-1 Vera Rubin Module (25× the AI compute of an H100, confirmed 2027 availability). SWaP — Size, Weight, and Power — is the engineering constraint that makes standard DGX server racks non-viable in orbit. A single H100 GPU requires 1.1 m² of radiator area to dissipate heat in vacuum; a full DGX H100 system requires 16 m² (ABI Research). That is not a satellite payload.

Understanding the SWaP tradeoffs is essential before evaluating any orbital compute vendor claim — the NVIDIA Vera Rubin Space-1 hardware breakdown explains the constraints that define what the entire product generation can and cannot do.

The full technical breakdown of Space-1, SWaP constraints, and the six-partner ecosystem — Aetherflux, Axiom Space, Kepler Communications, Planet Labs, Sophia Space, and Starcloud — is in NVIDIA Vera Rubin Space-1 — The Hardware Behind Orbital AI Compute.

What is China’s commercial underwater data centre and how does it compare to Microsoft Project Natick?

Beijing Highlander Digital Technologies (BHDT) / Shenzhen HiCloud is operating a sealed underwater data centre at 35m depth off Lingshui, Hainan Island — a 1,300-tonne pressure vessel targeting 24 MW capacity and claiming a Power Usage Effectiveness (PUE) of 1.07. For context: hyperscalers achieve ~1.1–1.2; traditional data centres average ~1.5–1.6; theoretical minimum is 1.0. Microsoft ran Project Natick trials successfully from 2018 to 2020 and did not commercialise. China’s domestic AI compute demand created unit economics that did not exist in Microsoft’s market context — the technology was proven; the commercial conditions were not. BHDT is on the US entity list. Subsea Cloud’s Jules Verne pod near Port Angeles, WA, is the US-based alternative.

The PUE 1.07 figure is the key benchmark — and understanding why China could reach it commercially while Microsoft could not is the subject of the comparative analysis of China’s underwater data centres and Project Natick.

The full comparative analysis is in China’s Underwater Data Centres and What Microsoft Abandoned with Project Natick.

Why does orbital solar power matter for data centre economics?

Low Earth orbit receives solar irradiance of approximately 1,361 W/m² — no atmospheric absorption, no weather, drastically reduced night cycles — delivering 10–40× the energy density of ground-based solar. That is a measurable input-side advantage with no grid dependency. ABI Research estimates orbital compute costs 78× more than terrestrial equivalents today; Google’s Project Suncatcher research sets $200/kg as the launch cost threshold at which parity becomes credible, projected around 2035. One important counterpoint: research from Saarland University, reported in Scientific American, finds that counting full lifecycle emissions — rocket propellant, satellite manufacturing, atmospheric reentry — could make orbital data centres an order of magnitude worse on greenhouse gas terms.

All of that solar energy becomes heat the moment compute hardware processes it — which is where the cooling physics matter as much as the power economics. The full analysis is in Power from the Sky — Orbital Solar Energy and the Data Centre Cost Equation.

How does cooling actually work in orbit and underwater — and why does it matter?

In orbit, heat can only leave a system by infrared radiation — every watt of waste heat requires radiator surface area. Underwater, sealed pressure vessels conduct waste heat through the hull to ambient seawater — a passive heat sink whose capacity far exceeds any data centre load at current scales — eliminating HVAC entirely. Cooling accounts for roughly 40% of traditional data centre energy overhead, so removing it restructures the entire energy budget. China’s Hainan facility achieves PUE 1.07 at 24 MW — the seawater advantage is commercially proven today. Orbital vacuum cooling achieves better theoretical PUE but is currently constrained to kW-scale deployments.

The full thermodynamic comparison, including PUE tables and radiator sizing, is in The Physics of Alternative Data Centre Cooling — Orbital Vacuum and Ocean Thermal.

When does any of this become a planning factor rather than a watch-list item?

For most organisations in 2026, alternative data centres belong on the watch list. The ABI Research 78× TCO premium is the quantitative basis for that answer. The conditions that change it are measurable: Starship reaching commercial flight frequency, launch costs below $200/kg, NVIDIA Space-1 shipping, and a draft SOC 2 or GDPR framework for orbital workloads. The Anthropic/SpaceX compute agreement (May 2026) — the first hyperscaler-level demand signal from an AI-native company — is a signal to track, not act on. The compliance blocker with no current answer: no jurisdiction governs data processed in orbit — a hard blocker in 2026 for any organisation handling regulated data. Atomic-6 / ODC.space is the closest thing to a purchasable product today: a sovereign rack at $3.5M/month with 2–3 year delivery.

The full decision framework — watch-list criteria, compliance gap analysis, and 24-month tracking signals — is in When Orbital and Underwater Data Centres Become an Infrastructure Planning Factor.

Resource Hub: Alternative Data Centre Library

The Orbital Environment: Deployments, Plans, and Hardware

• Axiom Space Orbital Data Centre Nodes — The First Commercial Launch in January 2026 — Operational proof: what two commercial ODC nodes on the ISS are actually running, and what kW-scale edge compute means in practice.
• SpaceX and the Million-Satellite FCC Filing — Orbital Data Centre Plans at Scale — Regulatory analysis of SAT-LOA-20260108-00016, the Anthropic compute agreement, SpaceX’s S-1 risk warnings, and what the million-satellite ambition would require.
• NVIDIA Vera Rubin Space-1 — The Hardware Behind Orbital AI Compute — The space computing product line, SWaP constraints, COTS vs. radiation-hardened silicon, and the six-partner ecosystem building the hardware layer.

The Underwater Environment and Cooling Physics

• China’s Underwater Data Centres and What Microsoft Abandoned with Project Natick — PUE 1.07 at 35m depth: why Hainan is commercial where Natick was not, and what the “thermal debt” controversy actually argues.
• The Physics of Alternative Data Centre Cooling — Orbital Vacuum and Ocean Thermal — Radiative cooling, seawater passive heat exchange, radiator sizing, and the PUE comparison across orbital, underwater, and terrestrial environments.
• Power from the Sky — Orbital Solar Energy and the Data Centre Cost Equation — The 10–40× orbital solar energy density advantage, the 78× TCO gap that currently cancels it out, and the conditions under which parity becomes credible by 2035.

Strategic Decision-Making

• When Orbital and Underwater Data Centres Become an Infrastructure Planning Factor — Watch-list vs. planning-factor threshold, compliance gap analysis (SOC 2, GDPR, HIPAA, FedRAMP), vendor lock-in risk with pre-revenue startups, and 24-month tracking signals.

Frequently Asked Questions

What is an orbital data centre (ODC)?

An orbital data centre is a computing facility mounted on satellites in low Earth orbit, powered by solar energy and dissipating waste heat via infrared radiation to the vacuum of space. The first two commercial nodes were deployed to the International Space Station by Axiom Space on 11 January 2026. For full operational detail: Axiom Space Orbital Data Centre Nodes.

What is “space-based computing” — is this the same as orbital compute?

The terms are used interchangeably in mainstream coverage. “Orbital data centre” (ODC) is the preferred industry and analyst term — used by ABI Research, NVIDIA, and SpaceNews; “space data center” and “space-based computing” appear more often in consumer tech coverage. This hub uses “orbital data centre” throughout; both terms describe the same category.

What is the difference between kW-scale orbital edge compute and MW-scale hyperscale orbital compute?

kW-scale edge deployments — Axiom Space’s ISS nodes, Kepler Communications’ 10-satellite cluster — are operational today, handling AI inference and data fusion at power levels a single satellite can sustain. MW and GW-scale ambitions (Starcloud-3, SpaceX’s million-satellite constellation, Google Project Suncatcher) require Starship launch economics and radiator arrays that do not yet exist at commercial scale. Conflating these two tiers is the most common error in mainstream coverage of this topic. The orbital AI hardware roadmap — from Jetson Orin to Space-1 — illustrates exactly where the capability gap sits today.

How close are we to cost parity between orbital and terrestrial compute?

ABI Research estimates orbital compute costs approximately 78× more than terrestrial equivalents today. Cost convergence is projected around 2035, contingent on Starship reaching commercial launch frequency and driving costs below $200/kg — the threshold Google’s Project Suncatcher research identifies as the break-even point. For the full economic analysis: Power from the Sky.

Is computing in space better for the environment than terrestrial alternatives?

The honest answer is contested. The solar power advantage is real — orbital irradiance of 1,361 W/m² with no atmospheric losses delivers 10–40× the energy density of ground-based solar. But research from Saarland University, reported in Scientific American, finds that counting full lifecycle emissions — rocket propellant combustion, satellite manufacturing, and atmospheric reentry — orbital data centres could generate an order of magnitude greater greenhouse gas emissions than terrestrial equivalents. Both findings are credible and should inform any ESG evaluation.

What are the compliance implications of processing data in orbit?

There are none — because no framework currently exists. SOC 2, GDPR, HIPAA, and FedRAMP do not address orbital workloads. The jurisdictional question of which country’s law governs data processed in orbit is legally unresolved. For organisations in regulated industries, this is a hard blocker in 2026. For the full compliance gap analysis: When Orbital and Underwater Data Centres Become an Infrastructure Planning Factor.

What workloads are viable candidates for orbital compute today?

Latency-tolerant, compute-heavy, parallelisable processing: Earth observation AI, cybersecurity analytics, data fusion for satellite-native datasets. Orbital AI inference — running pre-trained model inference where each request is independent — is viable at kW-scale edge nodes today. Distributed LLM training, which requires tightly coupled multi-GPU systems, is a 2030s capability. The China Hainan underwater data centre demonstrates what commercially viable alternative data centre workloads look like at scale today — 24 MW at PUE 1.07, running AI inference and data processing that does not require orbital positioning.

Where to go from here

The category is real, the deployments are small, and the economics are not there yet. What changes that verdict — and the timeline for when it changes — is laid out in When Orbital and Underwater Data Centres Become an Infrastructure Planning Factor. If you want the engineering foundation first, start with the physics of cooling. If you want the proof that this is happening, start with what Axiom Space launched in January 2026.