Aterio Identifies Potential Horizon 4 Delivery Risk

Imagery reviewed through 21 October 2026.

IREN is building GPU capacity for Microsoft at its Childress campus in the Texas Panhandle, under a five-year, $9.7 billion contract. The work is split into four phases, called Horizon 1 to Horizon 4. Each Horizon is a block of three liquid-cooled data halls with its own cooling plant, and carries 50 MW of IT load. Microsoft accepted Horizon 1 in August, and IREN is targeting delivery of the other three in the fourth quarter of 2026.

On 21 October, Aterio flew over Childress and captured its own optical and thermal images of the campus. We compared them with satellite images from 23 May, 24 June and 30 July to see how far each Horizon has come, and what that means for IREN's delivery dates.

Executive assessment

Based on construction progress visible in aerial and satellite imagery through 21 October 2026, Aterio estimates that Horizon 4 faces an elevated risk of delivery extending into Q1 2027. This is an independent construction-based assessment rather than confirmation of a delay to IREN's stated schedule.

Our flyover shows Horizon 4 at roughly the visible construction stage Horizon 3 had reached at the end of July, with most data hall generators still absent from their pads and liquid cooling pipes visible at only one hall. Repeating the observed construction intervals points to a risk of delivery extending into Q1 2027. Based on observed construction progress and historical phase comparisons, meeting the year-end target would appear to require a material acceleration in remaining visible construction activities, with a substantially faster completion pace than that observed for Horizon 3 between July and October. The comparison is indicative and does not account for potential parallel workstreams or schedule acceleration.

Horizon 2 appears on track for Q4 2026. Horizon 3 remains within reach of year-end: comparison with Horizon 1 points to delivery by December, subject to the remaining work and internal fit-out.

This is a construction-based estimate. It assumes timely power and equipment availability; imagery cannot establish the readiness of GPUs, internal systems or customer acceptance testing.

How we track progress

Each Horizon is built the same way: three data halls, a cooling plant that runs the liquid cooling, and a block of cooling fans. Each pair of Horizons also shares a network building, which links the GPUs across the data halls so each Horizon runs as one cluster. One network building serves Horizon 1 and 2, the other serves Horizon 3 and 4. Liquid-cooling pipes run from the network building through the data halls to the cooling plant and fans, and are insulated once they are in. Each data hall has eight generators and eight electrical rooms, so a Horizon has 24 of each across its data halls.

Childress campus, 30 July 2026. Source: Vantor.

To measure progress, we track the same items on every Horizon from the air: the generators and electrical rooms at each data hall, the cooling plant and its six generators, the heat-rejection units, the liquid-cooling pipes and the shared network building.

Our benchmark: Horizon 1

Horizon 1 is our benchmark because IREN announced on 13 August that Microsoft had accepted it. We use that announcement as a dated endpoint.

In the 24 June satellite image, Horizon 1 had every generator in place and its cooling plant was roofed. The main work left was insulating the cooling pipes, including on the last data hall and the cooling plant. The interval from this image to the acceptance announcement was 50 days.

Horizon 1, 24 June 2026: cooling pipes awaiting insulation, 50 days before the acceptance announcement. Source: Vantor.

By 30 July, the insulation was almost done, with only small sections on the last data hall and the cooling plant left. That was two weeks before the announcement.

Our 21 October thermal imagery adds a snapshot of operating activity. Large parts of Horizon 1’s cooling block show a strong heat signature, consistent with heat rejection from the data halls. Horizon 2's cooling block exhibited a lower apparent thermal signature than Horizon 1 during the 21 October aerial survey. This difference may be consistent with lower cooling activity at the time of observation, but the imagery alone cannot establish whether Horizon 2 is operational, undergoing testing, or carrying customer workloads.

Horizons 1 and 2 cooling blocks, 21 October 2026. Thermal (right) enhanced to remove noise and interface elements. Source: Aterio.

Horizon 3: close to finished

On 21 October, Horizon 3 had 22 of its 24 data hall generators in place, all of its cooling pipes installed, and its cooling plant roofed with all of its generators. The visible gaps were the last two data hall generators and insulation at one hall and the cooling plant. Its shared network building had two of its four generators and electrical rooms in. We assume that is enough to run one Horizon: IREN said Horizon 1 GPU commissioning was already under way in May, when satellite imagery showed two of four generators in place at its network building. Aterio cannot determine whether this configuration is sufficient for commissioning or operation without access to internal engineering and operating information.

This broadly resembles Horizon 1 in late June, although Horizon 1 already had every generator in place. Applying the same 50-day image-to-acceptance interval would put Horizon 3 around mid-December.

Year-end remains within reach for Horizon 3, with limited room for slippage. The forecast depends on closing the visible gaps and completing GPU installation, system testing and customer acceptance inside the halls.

Why Horizon 4 is at risk

Our 21 October flyover shows Horizon 4 with its heat-rejection block visually complete and its liquid cooling pipe racks up, but pipes installed in only one of its three data halls and no connection yet from the halls to its cooling plant, which is still under construction. This is about where Horizon 3 was on 30 July, and Horizon 3 still isn’t finished. Electrical rooms put it at the same point: 17 of Horizon 4’s 24 are in place, the same as Horizon 3 at the end of July, but only 6 are finished, against about 11 for Horizon 3. On backup generators, Horizon 4 is even further back: 5 on their pads and none finished, against 10 for Horizon 3 at the end of July.

Horizon 4 construction progress, 21 October 2026. Source: Aterio aerial survey.

Nineteen of Horizon 4’s 24 data-hall generators are not yet visible on their pads. Across the whole campus, 62 generators went onto their pads between 23 May and 21 October, about three a week on average. If that pace continues and every generator added from now on goes to Horizon 4, its last one would go in around early-to-mid December. Even if IREN sets them faster than that, generators are only part of what is left. Horizon 4 still needs liquid cooling pipes in two of its data halls, all of its pipes insulated and its cooling plant finished, plus commissioning and Microsoft’s acceptance testing.

At Horizon 3’s pace, Horizon 4 would reach the stage Horizon 3 is at today around mid-January. After that, it would still need commissioning and Microsoft’s acceptance testing. Crews freed up as Horizons 2 and 3 finish could speed up the work, but to be ready by year-end, Horizon 4 would need to move about twice as fast as Horizon 3 did between July and October.

What a slip would mean

If Horizon 4 delivery extends into 2027, the timing of associated commercial milestones could be affected, depending on contractual terms. Aterio has not independently verified the relevant billing, customer-acceptance, or revenue-recognition provisions and cannot determine whether a delay would have a material financial impact. The imagery does not establish the billing start date or quantify the financial effect; those depend on contract terms and customer acceptance. The Horizon buildout also provides a useful test of IREN’s delivery pace as it pursues further capacity at Childress and its other sites in 2027.

What to watch next

IREN reports its results on 5 November. We will be looking for any update on whether Microsoft has accepted Horizon 2, any change to the delivery targets for Horizons 3 and 4, and any detail on GPU installation, commissioning or customer testing.

About the dates in this report

The dates in this report are Aterio’s estimates, based on imagery, IREN’s disclosures and comparisons between Horizons. They are not commitments by IREN or Microsoft. Stage matching is approximate. Construction overlap, equipment availability, power, commissioning and testing could move delivery earlier or later.

Disclaimer

This report contains independent research and analysis prepared by Aterio using commercially available information, public company disclosures, licensed satellite imagery, and independently acquired aerial observations.

Construction status assessments are based on features visible in imagery collected on specified dates. These observations do not establish the operational readiness, internal construction progress, equipment functionality, commissioning status, or customer acceptance of any facility.

All estimated completion and delivery dates represent Aterio's independent assessments based on available information and stated assumptions. They are subject to uncertainty and may differ materially from actual outcomes. Aterio has not independently verified the complete construction schedules, contractual delivery obligations, or commissioning requirements of the companies referenced.

References to potential delays, commercial milestones, or financial implications are analytical assessments and should not be interpreted as confirmation of a contractual breach, operational failure, or financial loss.

The information is provided for informational and research purposes only and does not constitute investment advice, a recommendation to buy or sell securities, or a guarantee of future performance. Aterio makes reasonable efforts to ensure the accuracy of its research but does not warrant that all information, interpretations, or estimates are complete or error-free.