Proliferated low Earth orbit (pLEO) refers to a large constellation of hundreds or thousands of small satellites operating in low Earth orbit (LEO).
LEO is the region of space below an altitude of 2000 km, with orbital periods between 90-120 minutes.
The goal of pLEO is to provide resilient global coverage by having many redundant satellites, so the network can function even if some fail.
Key characteristics of pLEO:
- Large number of satellites: Having hundreds or thousands of satellites provides redundancy and resilience.
- Low altitude: pLEO satellites orbit from 160 km to 1200 km, which reduces latency compared to higher orbits.
- Global coverage: A large pLEO constellation can provide connectivity across the entire planet, including remote areas.
- Short satellite lifespan: pLEO satellites typically last 5-10 years before orbital decay, so constellations must be frequently replenished.
- Lower costs: Small satellites and mass production reduces pLEO costs compared to traditional satellites.
Applications of pLEO:
- Communications: pLEO can provide global broadband internet connectivity, including to remote areas and Internet of Things devices.
- Earth observation: The low altitude allows high-resolution imaging for tasks like weather monitoring.
- National security: pLEO enables resilient and redundant communications for the military in contested environments.
Challenges with pLEO:
- Space congestion: Large pLEO constellations increase collision risks and space debris, especially in the crowded LEO region.
- Orbital maintenance: Frequent orbit corrections and replacements are needed due to atmospheric drag and short satellite lifespans.
- Regulation: Guidelines are limited on pLEO constellation size, debris mitigation, and deorbiting defunct satellites.
Summary
Proliferated LEO provides global coverage and resilience through a large network of low-cost small satellites, but responsible management is needed to address congestion and sustainability issues.