Moreover, microorganisms on Nozomi are unlikely to have survived the 5 - year stay in the hostile environment of interplanetary space. (sciencemag.org)
References: Richardson et al. (2002), «Long - term trends in interplanetary magnetic field strength and solar wind structure during the twentieth Century», J. Geophys. (realclimate.org)
However, the general background of interplanetary dust in the inner solar system can not, by itself, account for the periodic spikes in calcium. (sciencedaily.com)