Lunar-R1: Efficient Reasoning of Large Language Models for Lunar Exploration via Reinforcement Learning

Xin-Yu Xiao, Ye Tian, Zhixian He, Qilin Chen, Shiqi Wang, Qianchen Xia


Abstract
We present Lunar-R1, an 8B-parameter reasoning model tailored for lunar science and mission operations, developed through continued pre-training, supervised fine-tuning, and reinforcement learning. To optimize the accuracy-efficiency trade-off, we introduce Latent Difficulty Perception (LDP), a lightweight mechanism that leverages final-layer hidden states to estimate query difficulty and regulates Chain-of-Thought generation length via difficulty-aware reward modeling. We construct Lunar-QA, an expert-verified benchmark derived from authentic lunar mission materials, and further evaluate on domain-specific tasks spanning astronomy and astrodynamics. Experimental results demonstrate that LDP reduces average token consumption by 38.9% while improving reasoning accuracy. Profiling on an RK3588 NPU yields 0.54 J/token energy efficiency and 380 ms time-to-first-token latency, validating feasibility for lunar surface edge deployment.
Anthology ID:
2026.emnlp-industry.5
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing: Industry Track
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Pepa Atanasova, Gholamreza Haffari, Minghan Wang
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
50–69
Language:
URL:
https://aclanthology.org/2026.emnlp-industry.5/
DOI:
Bibkey:
Cite (ACL):
Xin-Yu Xiao, Ye Tian, Zhixian He, Qilin Chen, Shiqi Wang, and Qianchen Xia. 2026. Lunar-R1: Efficient Reasoning of Large Language Models for Lunar Exploration via Reinforcement Learning. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing: Industry Track, pages 50–69, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Lunar-R1: Efficient Reasoning of Large Language Models for Lunar Exploration via Reinforcement Learning (Xiao et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-industry.5.pdf