---
type: source
title: "NEO Survey: Only 45% of Expected 140m+ Asteroids Discovered; NEO Surveyor Telescope Takes Shape for 2027 Launch"
author: "NASA Science / JPL / CNEOS"
url: https://science.nasa.gov/blogs/neo-surveyor/2026/05/05/nasas-next-gen-near-earth-asteroid-space-telescope-takes-shape/
date: 2026-05-05
domain: space-development
secondary_domains: []
format: article
status: unprocessed
priority: medium
tags: [planetary-defense, neo-survey, neo-surveyor, asteroid, existential-risk, catalog-completion]
intake_tier: research-task
---

## Content

**Current NEO survey status (as of 2025-2026):**
- ~45% of the expected population of NEOs larger than 460 feet (140m) have been discovered — the congressional 90% completion goal set in 2005 remains half-achieved 20 years later
- ~37,378 NEOs discovered as of December 30, 2024 (all sizes)
- ~2,500 potentially hazardous asteroids (PHAs) identified as of August 2025
- The 45% figure represents ground-based survey limits — dark asteroids and comets reflecting little visible light are hardest to detect

**Vera C. Rubin Observatory (operating 2025):**
- Chile-based, surveys southern sky for transient events
- Expected to increase total known asteroids by factor of 10-100
- Will push 140m+ NEO discovery ratio to approximately 60%

**NEO Surveyor mission:**
- Critical Design Review passed February 6, 2025
- NASA Standing Review Board confirmed all technical performance measures met
- Status (May 2026): hardware construction and testing phase
- Launch: September 2027 on SpaceX Falcon 9 from Florida
- Mission goal: Find at least two-thirds (67%) of NEOs larger than 140m
- Congressional 90% PHA goal: achievable within 12-year mission lifetime (~2039)
- First space telescope specifically designed for planetary defense (infrared, detects dark asteroids)

**Critical gap:** Rubin + NEO Surveyor combined = ~76% coverage within 5 years of 2027 launch. Full 90% goal: ~2039. This means 24% of potentially hazardous 140m+ asteroids remain unknown through 2039.

**ESA Hera context:**
- Not a survey mission — Hera conducts detailed characterization of already-identified DART target (Didymos system)
- Arrives November 2026 (one month ahead of schedule)
- Will refine kinetic impactor efficiency measurements — improves deflection planning, not discovery

## Agent Notes

**Why this matters:** For Belief 1 disconfirmation: even optimistic planetary defense trajectory leaves 24% of 140m+ PHAs unknown through 2039. The survey gap is the single most important limitation on the planetary defense argument for Earth-based resilience. You cannot deflect what you haven't found with adequate warning time. Even if kinetic impactors work perfectly (DART validated), you need decades of warning — and we don't have that for 55% of threats today.

**What surprised me:** The slow progress on the congressional mandate — 20 years after the 90% goal was set in 2005, we're at 45%. Ground-based surveys have hit diminishing returns. The space-based solution (NEO Surveyor) is the right approach but has been delayed for years and only launches in 2027.

**What I expected but didn't find:** Significant progress beyond 45% from ground-based surveys since 2020. The Vera Rubin Observatory is the biggest recent addition and should push to ~60% — but that still leaves 40% unknown.

**KB connections:**
- Belief 1 (multiplanetary imperative): The survey gap directly validates why asteroid impact remains a live existential risk even with deflection capability
- the 30-year space economy attractor state is a cislunar industrial system — planetary defense infrastructure is complementary to space development, not substitute
- No existing KB claim specifically covers NEO survey completion status — this would be a new claim area

**Extraction hints:**
- New claim candidate: "The NEO survey is 45% complete for 140m+ asteroids as of 2025, meaning more than half of potentially hazardous objects remain undiscovered — the survey gap is the binding constraint on asteroid impact defense, not deflection capability"
- Timeline claim: "The congressional goal of 90% PHA detection completeness will not be achieved until approximately 2039 even with NEO Surveyor's 2027 launch"
- This creates an interesting interaction with DART data: deflection is validated, but the bottleneck is detection, not deflection

**Context:** The NEO Surveyor's May 2026 "takes shape" update confirms it's on track for 2027 launch — this is meaningful program health news for a mission that has experienced multiple delays and budget threats.

## Curator Notes

PRIMARY CONNECTION: Belief 1 (humanity must become multiplanetary to survive long-term)
WHY ARCHIVED: The 45% survey completion figure is the single most concrete evidence for why asteroid impact remains a live existential risk despite DART's deflection success — needed for accurate claim calibration on planetary defense vs multiplanetary insurance
EXTRACTION HINT: Focus on the detection gap (45% known) rather than deflection capability (DART validated) — these are separate variables. A new claim on survey completion status would be genuinely new KB content. Also note: Rubin Observatory 60% + NEO Surveyor 76%/2032 + full goal 90%/2039 timeline is precise and claim-worthy