Editing Project HARP (section)

=== Martlet 2A, 2B, 2C family ===
The Martlet 2A, 2B, and 2C represented the earliest of the Martlet 2 16-inch (406&nbsp;mm) test projectiles. Martlet 2A was designed simultaneously with the Martlet 1 with a range of interest being 70 to 200 kilometers. Most carried multi-type research payloads studying the upper atmosphere and near-space conditions. Due to their low cost per missile launch, they were used to test out single payloads. Despite similarities in missile airframe, the Martlet 2A, 2B, and 2C featured differences in their structural materials and mechanical details. For the Martlet 2A, the liquid payload was loaded into an aluminum, tapered liner inside the missile body. But by the development of the Martlet 2C series, the aluminum insert was abandoned altogether to allow the liquid payload to be housed in contact with the steel body, increasing the quantity of the liquid payload that could be carried.<ref name=":11" />