howclose.to
Earth & Space · Updated July 2026Momentum · accelerating ↗

How close are we to planetary defense?Could we stop an asteroid hitting Earth?

or, simply: Could we stop an asteroid hitting Earth?or, precisely: How close are we to planetary defense?

Humanity has demonstrated one asteroid-deflection technique, but the survey needed to find regional-scale threats is only halfway to its statutory goal.We have moved one harmless asteroid. The bigger gap is seeing a dangerous one early enough: more than half of the estimated regional-size population is still unknown.

We are here

Regional-size survey reaches only 45% - NASA's inspector general reported 45% estimated completeness for near-Earth objects at least 140 metres across, versus the missed 90% goal. Next up - Hera targets Didymos rendezvous (expected Nov 2026).

01 · Where we stand

State of playWhere planetary defense stands right now

The current stage, the honest metric, and the single threshold that gates the next stage. Each threshold is a falsifiable claim with a named next test.How far up the ladder we've climbed, the honest verdict, and the one thing blocking the next step.

The five stagesMaturity ladder
Deployed
Out in the real worldDeployed at scale
Scaling
Making it cheap enough at scaleScaling toward competitive cost
Engineering← HERE
Building one that pays for itselfEngineering a system that pays back
Lab demo
Shown to work in a labDemonstrated in the laboratory
Theoretical
The idea is worked out on paperTheoretical basis established
The honest verdictVerified state

We have moved one harmless asteroid. The bigger gap is seeing a dangerous one early enough: more than half of the estimated regional-size population is still unknown.Humanity has demonstrated one asteroid-deflection technique, but the survey needed to find regional-scale threats is only halfway to its statutory goal.

45Best result so farNASA estimate, April 2025
90US statutory survey goal - not a forecast
Blocking the next stepBlocking threshold

Find almost every regional-size threatNinety-percent regional-threat survey Next test: NEO Surveyor launches and begins its five-year infrared survey of bright and dark objects.

The verdict, in five rungsHow far up the ladder↓ next — the thresholds & the gap
01 · The evidence

The thresholds that gate the next stageWhat has to happen next

Each threshold is a falsifiable claim with a named next test; the gap chart shows how far today's metric sits from the goal.Each row is one thing that has to be proven — and how far today's number is from the target.

Kinetic-impact demonstrationMove an asteroid on purpose✓ Achieved · Sep 2022
100%
Proven byDART completed the first full-scale demonstration of asteroid deflection.
Ninety-percent regional-threat surveyFind almost every regional-size threatIn progress
50%
Next testNEO Surveyor launches and begins its five-year infrared survey of bright and dark objects.
THRESHOLDS - Thresholds for Planetary Defense.
Scale
Estimated NEOs at least 140 m discovered over time, with measured values, projected values, and a goal at 90 %.020406080100Estimated NEOs at least 140 m discovered · %Year20142025GOAL 90 · US statutory survey goal - not a…NASA OIG baselineNASA estimate, April 2025~45 % to goal
NOTE - These percentages are estimates derived from population models, not a direct census. The 90% mark is the still-unmet US survey goal for objects at least 140 metres across; it is not a completion forecast.
02 · How we got here

The record behind the verdict

Major events set large; context events set small but never hidden. Everything below the TODAY rule is a schedule, not a result.

1994-20042 events1 shown

Impacts become a present-day hazard

Impacts become a present-day hazard moved the field from shoemaker-levy 9 strikes jupiter to one-kilometre survey goal set. The results narrowed the next question without closing it.

1994
Shoemaker-Levy 9 strikes JupiterExperiment
Twenty-one comet fragments hit Jupiter while spacecraft and observatories watched, showing large impacts occurring in the modern Solar System.
Global observatories and NASA
1998
One-kilometre survey goal set
The United States directed NASA to find 90% of near-Earth asteroids at least one kilometre across.
US Congress and NASA
2005-20122 events1 shown

The survey expands to regional threats

The survey expands to regional threats moved the field from survey threshold drops to 140 metres to kilometre survey passes 90%. The results narrowed the next question without closing it.

2005
Survey threshold drops to 140 metresPolicy
Congress set a goal for NASA to detect 90% of near-Earth objects at least 140 metres wide by 2020.
US Congress
2011
Kilometre survey passes 90%
NEOWISE estimated that 911 of 981 near-Earth asteroids larger than one kilometre were known, or 93%.
NASA NEOWISE
2013-20202 events1 shown

Chelyabinsk exposes the blind spots

Chelyabinsk exposes the blind spots moved the field from chelyabinsk arrives without warning to nasa creates a defense office. The results narrowed the next question without closing it.

2013
Chelyabinsk arrives without warningSetback
An approximately 18-metre object exploded over Chelyabinsk, damaging buildings and injuring more than 1,000 people.
Global observing community
2016
NASA creates a defense office
NASA established the Planetary Defense Coordination Office to manage detection, tracking, characterization and mitigation work.
NASA
2021-20253 events1 shown

Humanity moves an asteroid

Humanity moves an asteroid moved the field from dart launches a deflection test to hera launches to the impact site. The results narrowed the next question without closing it.

2021
DART launches a deflection test
NASA launched the first mission built to demonstrate asteroid deflection with a kinetic impactor.
NASA and Johns Hopkins APL
2022
DART changes an asteroid's orbitExperiment
DART struck the harmless moonlet Dimorphos and shortened its orbit around Didymos by about 32 minutes.
NASA DART
2024
Hera launches to the impact site
ESA launched Hera to survey Dimorphos and reduce uncertainties around the DART result.
European Space Agency
2026-20271 event0 shown

Measuring the shove and widening the search

Measuring the shove and widening the search begins with hera targets didymos rendezvous. The result established the next question for the field.

2026
Hera targets Didymos rendezvousDeploymentTarget
Hera is on course to reach the binary system and begin the close measurements DART could not make from Earth.
European Space Agency
2025-20272 events1 shown

Events outside the declared eras

Events outside the declared eras moved the field from regional-size survey reaches only 45% to neo surveyor launch readiness. The results narrowed the next question without closing it.

2025
Regional-size survey reaches only 45%SetbackWe are here
NASA's inspector general reported 45% estimated completeness for near-Earth objects at least 140 metres across, versus the missed 90% goal.
NASA Office of Inspector General
2027
NEO Surveyor launch readinessDeploymentTarget
NASA lists its dedicated infrared asteroid telescope for launch no earlier than September 2027; the date and survey result remain future work.
NASA and JPL
— end of record · 12 shown, 0 hidden —
12 events · below the TODAY rule = scheduled, not done
03 · The data behind the verdict

Why the meters read the way they do

The learning curves and comparisons that justify each threshold's percentage. Every series is measured, with the source event linked in the timeline above.

Only 45% of estimated ≥140 m NEOs are found; the 90% survey goal remains 45 points away.We can move what we can see; only 45% of ≥140 m NEOs are estimated found.Solid fill = modeled discovered share · one point = estimate by year · dashed rail = statutory target, not forecast · population model, not direct census · 2014–2025Solid fill = estimated discovered share · hollow point = current estimate · dashed rail = survey goal · 2014–2025
Regional-threat asteroid survey completionNASA estimated survey completeness at 24% in 2014 and 45% in 2025. The 90% line is a statutory goal, not a forecast. NEO Surveyor remains a future mission.ESTIMATED ≥140 M NEO POPULATION DISCOVERED0%25%50%75%100%90% STATUTORY GOALNOT A FORECASTOBSERVED ESTIMATE · 45%APRIL 20252014 · 24%FUTURE MISSION · NOT ACHIEVEDNEO Surveyor · five-year infrared baseline surveyMODELED POPULATION ESTIMATE · NOT A DIRECT CENSUS
NASA · AS OF JUL 2026
04 · What it unlocks

If the remaining tests pass

Downstream capabilities, drawn dashed because they depend on results not yet in.

Planetary DefensePreventable impact disastersturn some asteroid impacts from unavoidable natural disasters into events we can see and avertRapid small-body reconnaissancebuild navigation and characterization tools that also help asteroid science and explorationInternational hazard coordinationcreate shared warning and response systems for a threat that does not respect borders
05 · Sources

Where every number comes from

6 sources — every figure on this page traces to one.

  1. NASA OIG - planetary-defense strategy audit (2025)assets.science.nasa.gov
  2. NASA - Double Asteroid Redirection Testscience.nasa.gov
  3. NASA JPL - NEO Surveyorjpl.nasa.gov
  4. ESA - Hera missionesa.int
  5. NASA - NEOWISE survey resultscience.nasa.gov
  6. NASA - Chelyabinsk impact retrospectivescience.nasa.gov