Compact, Lightweight Bolt-on Deorbit Device for Spacecraft

Two simple bolt-on de-orbit device configurations developed during Phase I will be carried to the CDR level for Phase II culminating in a ready-to-fly de-orbiter at the end of the project.nbsp; The first is a passive de-orbiter suitable for use at altitudes up to 1200 km where no vane sail articulation is needed. For altitudes above 1200 km our analysis showed that in order to decay within the 25-year quot;requirementquot; an articulating vane sail type de-orbiter is needed for rough-pointing against solar pressure.nbsp; Even if the vane sail of the de-orbiter is mis-pointed by 45 degrees, it will still see about 70 percent solar pressure drag. For these higher altitudes anbsp;passively articulating bolt-on de-orbit device based on two-way shape memory alloy is used. The two-way shape memory alloy unfurls to a large area against solar pressure during the sun-side of the orbit when it is warmed, and when its quot;back is turned against the sunquot; on its way to the eclipse side of the orbit, it cools down and folds back to a low area device decreasing the solar pressure on it as it exits the sun side.nbsp; The de-orbiter area can be tailored such that after it crosses the 1200 km limit on its way down, the active area against the atmosphere is still sufficient for de-orbiting within 25 years.nbsp; The SMA based de-orbiter has no need for motors or sources of power and the mass and stowed volume gained can be used for an increase in the amount of material to package making it suitable for both altitude regimes.