A probabilistic approach is applied to assess the required and the available retrorocket-phase (RRP) power needed to prevent, to an extent possible, unsafe landing of a spacecraft on a planet, such as, e.g., Mars. It is shown that the available power of the rocket engines should exceed considerably the required power at this phase to make sure that the probability of unsafe landing, because of insufficient power, is low enough. The obtained results can be used to select, on the design stage and on the probabilistic basis, the level of RRP braking power for situations of the type in question. They indicate, however, that landing on a planet will remain a highly risky business for many years to come.

应用概率方法来评估在可能的程度上防止航天器在诸如例如火星的行星上的不安全着陆所需的和可用的逆火箭阶段(RRP)功率。结果表明，该阶段火箭发动机的可用功率应大大超过所需功率，以确保因功率不足而导致不安全着陆的概率足够低。获得的结果可用于在设计阶段和概率基础上为所讨论的类型选择 RRP 制动力的水平。然而，他们表明，在未来很多年，登陆一个星球仍将是一项高风险的业务。