Since then, the flash period is slowly increasing again, but we remain alert. Flash period of 81-116 J as a function of days since the first measurement. Two sudden periods of acceleration have been observed so far. Although single period decreases can easily be explained by fuel leaks, there has been no explanation so far for a double decrease with an interval of one year. It has already happened several times, and currently the theory of a periodic sublimation of frozen fuel is gaining ground.
More research is required.
A regular fuel leak has happened many times just after the launch. It is sometimes commanded in order to avoid explosion. Figure 15 shows a striking example of this. It is the case of 71- 86 J, which underwent a sharp decrease in rotation period a few weeks after launch. Flash period of 71- 86 J as a function of days since the launch.