Vals Time Horizon Index: Kerbal Space Program (Time Horizon Index: KSP)
We show this table for reference; we do not rank on it.
A Vals AI agent benchmark that gives each system five days to build and run a space program in Kerbal Space Program.
Evaluation results published by Vals AI. Published leaderboard aggregates and evaluation settings only. Dataset contents are not included.
KSP progress on Time Horizon Index: KSP — October 7, 2026
We mirror the published ksp progress view for Time Horizon Index: KSP. Claude Opus 5.5 leads the public snapshot at 91.333%, followed by GPT-6 Astra (90.500%) and Claude Fable 5.1 (63.333%). We do not use these results to rank models overall.
Claude Opus 5.5
Anthropic
GPT-6 Astra
OpenAI
max reasoning
Claude Fable 5.1
Anthropic
13 modelsAgenticCurrentDisplay onlyUpdated October 7, 2026
KSP progress table (13 models)
| Rank | Model / configuration | Score | Parameters (B) | Open / closed |
|---|---|---|---|---|
| 1 | Claude Opus 5.5Anthropic | 91.333% | Not reported | Closed |
| 2 | GPT-6 AstraOpenAImax reasoning | 90.500% | Not reported | Closed |
| 3 | Claude Fable 5.1Anthropic | 63.333% | Not reported | Closed |
| 4 | Gemini 4 ArgonGooglehigh reasoning | 52.500% | Not reported | Closed |
| 5 | GPT-5.6 SolOpenAImax reasoning | 23.833% | Not reported | Closed |
| 6 | Gemini 3.8 FlashGooglehigh reasoning | 18.833% | Not reported | Closed |
| 7 | Claude Opus 5Anthropic | 18.833% | Not reported | Closed |
| 8 | Claude Opus 4.8Anthropic | 11.833% | Not reported | Closed |
| 9 | Kimi K3Moonshot AImax reasoning | 10.500% | Not reported | Open |
| 10 | GPT-5.5OpenAIxhigh reasoning | 8.333% | Not reported | Closed |
| 11 | Grok 4.5xAIhigh reasoning | 6.333% | Not reported | Closed |
| 12 | Grok 4.6xAIhigh reasoning | 5.833% | Not reported | Closed |
| 13 | Muse Spark 1.1Metaxhigh reasoning | 1.667% | Not reported | Closed |
How Time Horizon Index: KSP is shown here
BenchLM mirrors the public Vals AI Time Horizon Index: KSP leaderboard captured from https://www.vals.ai/benchmarks/time_horizon_index and updated by Vals on October 7, 2026. The snapshot preserves overall scores, uncertainty, latency, cost-per-test metadata, and task-level scores where Vals publishes them.
Time Horizon Index: KSP is display only on BenchLM. Vals proprietary or Vals-hosted aggregate views are useful context, but BenchLM does not use them as weighted ranking inputs or as a replacement for benchmark-native source records.
Snapshot
The published Time Horizon Index: KSP snapshot places Claude Opus 5.5 first at 91.333%. The third row is 28.000 points behind. The broader top-10 range is 83.000 points, so the table still separates the published systems.
13 models have been evaluated on Time Horizon Index: KSP. The benchmark falls in the Agentic category. We keep external benchmark mirrors separate from the weighted global scoring system, so these results remain source-specific evidence. Time Horizon Index: KSP is currently displayed for reference but excluded from the scoring formula, so it does not directly affect overall rankings.
About Time Horizon Index: KSP
Year
2026
Tasks
30 progressively harder Kerbal Space Program missions
Format
Mission-ladder progress with partial credit
Difficulty
Long-horizon autonomous computer use and planning
The first Time Horizon Index uses a 30-rung mission ladder and awards partial progress within a rung. We mirror the four launch rows and progress-efficiency scores. Each result comes from one five-day run with a computer-use harness, so the small system-level table remains display only.
Freshness and provenance
Version
Time Horizon Index: KSP 2026
Refresh cadence
Quarterly
Staleness state
Current
Question availability
Public benchmark set
BenchLM uses freshness metadata to decide whether a benchmark should still be treated as a strong differentiator, a benchmark to watch, or a display-only reference. For the full scoring policy, see the BenchLM methodology page.
Questions
What does Time Horizon Index: KSP measure?
A Vals AI agent benchmark that gives each system five days to build and run a space program in Kerbal Space Program.
Which model leads the published Time Horizon Index: KSP snapshot?
Claude Opus 5.5 currently leads the published Time Horizon Index: KSP snapshot with 91.333% ksp progress. BenchLM shows this benchmark for display only and does not use it in overall rankings.
How many models are evaluated on Time Horizon Index: KSP?
The October 7, 2026 snapshot contains 13 AI models.
Know when it’s worth switching models
The model to choose, the cheaper alternative, and the release we would wait on.
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