Editing Cosmic ray visual phenomena (section)

===SilEye-Alteino and ALTEA projects===
The [[SilEye-Alteino]] and [[Anomalous Long Term Effects in Astronauts' Central Nervous System]] (ALTEA) projects have investigated the phenomenon aboard the [[International Space Station]], using helmets similar in nature to those in the ALFMED experiment. The SilEye project has also examined the phenomenon on Mir.<ref name="Avdeev2002" /> The purpose of this study was to examine the particle tracks entering the eyes of the astronauts when the astronaut said they observed a LF. In examining the particles, the researchers hoped to gain a deeper understanding of what particles might be causing the LF. Astronauts wore the SilEye detector over numerous sessions while on Mir. During those sessions, when they detected a LF, they pressed a button on a joystick. After each session, they recorded down their comments about the experience. Particle tracks that hit the eye during the time when the astronauts indicated that they detected a LF would have had to pass through silicon layers, which were built to detect protons and nuclei and distinguish between them.

The findings show that "a continuous line" and "a line with gaps" was seen a majority of the time. With less frequency, a "shapeless spot", a "spot with a bright nucleus" and "concentric circles" were also reported.<ref name="Avdeev2002" />{{rp|518}} The data collected also suggested to the researchers that one's sensitivity to the LF tends to decrease during the first couple of weeks of a mission. With regards to the probable cause of the LF, the researchers concluded that nuclei are likely to be the main cause. They based this conclusion off of the finding that in comparison to an "All time" period, an "In LF time window" period saw the nucleus rate increase to about six to seven times larger, while the proton rate only increased by twice the amount when comparing the two time periods. Hence, the researchers ruled out the Cherenkov effect as a probable cause of the LF observed in space, at least in this case.