A laser-optical system to re-enter or lower low Earth orbit space debris

• Clearing space debris is crucial for future space activities.
• Pulsed Laser Orbital Debris Removal (LODR) is the most effective way to cause debris objects to re-enter.
• We consider small (<1 kg) and large (up to 8000 kg) targets, and three LODR station locations to address each.
• LODR is versatile because it can remove small and large debris simultaneously, and works on multi-ton objects.
• We estimate a cost of 12M$ to lower ENVISAT 40 km, in about 2 months.

Collisions among existing Low Earth Orbit (LEO) debris are now a main source of new debris, threatening future use of LEO space. Due to their greater number, small (1–10 cm) debris are the main threat, while large (>10 cm) objects are the main source of new debris. Flying up and interacting with each large object is inefficient due to the energy cost of orbit plane changes, and quite expensive per object removed. Strategically, it is imperative to remove both small and large debris. Laser-Orbital-Debris-Removal (LODR), is the only solution that can address both large and small debris. In this paper, we briefly review ground-based LODR, and discuss how a polar location can dramatically increase its effectiveness for the important class of sun-synchronous orbit (SSO) objects. With 20% clear weather, a laser-optical system at either pole could lower the 8-ton ENVISAT by 40 km in about 8 weeks, reducing the hazard it represents by a factor of four. We also discuss the advantages and disadvantages of a space-based LODR system. We estimate cost per object removed for these systems. International cooperation is essential for designing, building and operating any such system.