Orange Herald
UK · 1957 · 720 kilotons · fusion-boosted
Overview
Largest UK nuclear test.
With a yield of 720 kilotons, the Orange Herald is 48× more powerful than the Hiroshima bomb. As a fusion-boosted weapon, it derives its energy from fusion-boosted fission reactions.
Orange Herald Blast Effects
The table below shows the calculated radius of each effect zone for an air burst (optimal altitude, maximum blast spread) and a surface burst (ground level, with massive radioactive fallout). Formulas are scaling laws from The Effects of Nuclear Weapons (Glasstone & Dolan, 1977).
| Effect zone | Air burst | Surface burst |
|---|---|---|
| Fireball radius | 2.02 km | 1.61 km |
| Severe blast (20 PSI) | 4.23 km | 2.32 km |
| Moderate blast (5 PSI) | 9.03 km | 4.97 km |
| Light blast (1 PSI) | 25.69 km | 14.13 km |
| 3rd-degree thermal burns | 9.94 km | 5.97 km |
| 2nd-degree thermal burns | 17.81 km | 10.69 km |
| Lethal fallout zone | minimal | ~166.8 km |
All values are 1-D ground-distance estimates from the detonation point. Real-world effects depend on terrain, weather, and building construction.
Run the Orange Herald on a City
Use the interactive simulator to detonate the Orange Herald on any city worldwide. Click any location on the map to see the fireball, blast, and thermal radii overlaid on real geography with population-density-based casualty estimates.
🎯 Simulate Orange HeraldRelated Weapons
FAQ
How big is the Orange Herald blast radius?
In an air burst, the Orange Herald produces a fireball roughly 2.02 km in radius and a 5 PSI moderate-blast zone of about 9.03 km — the area in which most residential buildings would collapse. The 1 PSI light-damage radius extends to roughly 25.69 km, where windows shatter.
What is the yield of the Orange Herald?
The Orange Herald has a yield of 720 kilotons of TNT equivalent. That is 48× more powerful than the Hiroshima bomb.
Is the Orange Herald bigger than the Hiroshima bomb?
The Hiroshima bomb (Little Boy) had a yield of approximately 15 kilotons. The Orange Herald at 720 kilotons is 48× more powerful than the Hiroshima bomb.
What thermal burn radius does the Orange Herald produce?
Thermal radiation from the Orange Herald can cause 3rd-degree burns out to roughly 9.94 km and 2nd-degree burns out to 17.81 km in an air burst. Surface bursts reduce these radii by approximately 40 percent due to ground absorption.