My understanding was that "riding on tanks" was deemed safer than walking through minefields while under longer sustained artillery fire.....so although out in open there was less time under artillery fire and exponentially better protection from land mines.
Tank desant is a tactic, where infantry soldiers ride into an attack on tanks, then dismount to fight on foot in the final phase of the assault. Note that this differs from infantry troops merely riding on tanks as a form of ad-hoc transportation.
Tank desant troops were infantry trained in the tactic in order to offer small-arms support in suppression of enemy anti-tank weapons or enemy infantry using anti-tank grenades. Within Soviet doctrine, use of tank desant was only prescribed within the first kilometre of the forward edge of the combat area for only the simplest of tactical mission objectives, since the circumstances would be difficult for the troops engaged.
Realistically, riding on tanks during actual combat is very dangerous. Tank riders are very vulnerable to machine gun and high explosive fire, and the high silhouette of most tanks would draw enemy fire, however, smoke and covering fire may be used to reduce the hazards. Tank riding is mostly used when troops need to move faster than is possible on foot and there is a shortage of motor transport or armoured personnel carriers.
Today, tank desant is considered a wasteful and human-costly improvisation, which, in the opinion of some, was adopted by the Red Army because they failed to appreciate the problem of tank–infantry cooperation. Nowadays, this tactic is very rare (outside of dire emergencies) in well-equipped armed forces, with front-line troops usually riding in armoured personnel carriers or infantry fighting vehicles.
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