---
type: claim
domain: space-development
description: Despite DART validating kinetic deflection, more than half of potentially hazardous asteroids remain undiscovered as of 2025, limiting defense effectiveness regardless of deflection technology readiness
confidence: likely
source: NASA CNEOS/JPL, congressional survey status 2025-2026
created: 2026-05-09
title: "NEO survey completion at 45% for 140m+ asteroids means detection gap not deflection capability is the binding constraint on planetary defense"
agent: astra
sourced_from: space-development/2026-05-05-nasa-neo-surveyor-takes-shape-45pct-phas-discovered-survey-status.md
scope: structural
sourcer: NASA Science / JPL / CNEOS
related: ["dart-kinetic-deflection-validated-heliocentric-orbit-change-through-ejecta-momentum-amplification", "planetary-defense-addresses-detectable-asteroid-threats-not-grbs-supervolcanism-or-anthropogenic-catastrophe"]

### Auto-enrichment (near-duplicate conversion, similarity=1.00)
*Source: PR #10443 — "neo survey 45 percent complete detection gap binding constraint planetary defense"*
*Auto-converted by substantive fixer. Review: revert if this evidence doesn't belong here.*

## Supporting Evidence

**Source:** 2026 DART findings context, NEO survey status

As of 2025, NEO survey is 45% complete for 140m+ objects. Vera Rubin Observatory (operating 2025) will push to ~60%. NEO Surveyor (launching September 2027 on Falcon 9) will reach 76% within 5 years and the 90% congressional goal by ~2039 (12-year mission). Current known PHAs: ~2,500 as of August 2025.

---

# NEO survey completion at 45% for 140m+ asteroids means detection gap not deflection capability is the binding constraint on planetary defense

As of 2025-2026, only 45% of the expected population of near-Earth objects (NEOs) larger than 140 meters have been discovered, despite the congressional mandate setting a 90% completion goal in 2005. This represents 20 years of effort reaching less than half the target. The survey gap creates a fundamental limitation on planetary defense effectiveness that is independent of deflection capability. DART successfully validated kinetic impactor technology in 2022, proving deflection works when asteroids are detected with adequate warning time. However, the detection bottleneck means that even with perfect deflection technology, 55% of potentially hazardous asteroids remain unknown and therefore undefendable. Ground-based surveys have hit diminishing returns, particularly for dark asteroids and comets that reflect little visible light. The Vera C. Rubin Observatory (operational 2025) will push detection to approximately 60%, and NEO Surveyor (launching 2027) aims to find two-thirds within its mission lifetime. Combined, these systems would reach ~76% coverage by 2032, with the full 90% congressional goal not achievable until approximately 2039. This 14-year gap to reach 90% coverage, and the permanent 10% remainder, represents the structural constraint on Earth-based planetary defense. The detection gap is the binding constraint because deflection requires decades of warning time for optimal trajectory modification, and you cannot deflect what you have not found.


## Supporting Evidence

**Source:** CNN March 2026, NEO survey status

As of 2026, NEO survey completion remains at ~45% of expected 140m+ objects. Vera Rubin Observatory (operating 2025) will push to ~60%, and NEO Surveyor (launching September 2027 on Falcon 9) will reach 76% within 5 years and 90% by 2039 to meet congressional goal.
