What type of security mission involves protecting against surprise attacks?

The mission type that involves protecting against surprise attacks is a screening mission. A screening operation is designed to provide early warning and to detect any enemy presence or movement, thereby safeguarding the main body of forces. By maintaining a layer of troops to observe and report on enemy actions without engaging directly, a screening force can ensure that any potential threats are identified before they can launch a surprise attack. This allows the main force to prepare for engagement or to reposition as necessary to mitigate risks.

In contrast, a cover mission primarily focuses on a more defensive posture, often aimed at protecting friendly forces or ensuring that they can conduct their operations without interference. A guard mission provides security for larger formations, typically by protecting against ground attack and allowing safe movement. An area mission entails securing a specified location, often for extended periods, but it does not specifically address the idea of preventing surprise attacks on the move like a screen does.