MMHO (Multi-Mission Heliocentric Observatory) is an exploratory mission concept that investigates the scientific potential of a small constellation of widely separated spacecraft operating on a shared heliocentric orbit. The concept consists of three identical observatories spaced approximately 120° apart, forming ultra-long baselines on the order of hundreds of millions of kilometers. Rather than focusing on a single scientific objective, MMHO explores a multi-modal observational strategy combining continuous inter-spacecraft laser ranging, wide-field optical/infrared telescopes, and microwave antennas. A key feature of the concept is reactive observing: when anomalous inter-spacecraft signals or spacetime perturbations are detected above predefined thresholds, onboard rule-based logic triggers rapid repointing of telescopes and antennas toward the inferred sky region to enable near-real-time electromagnetic follow-up. In the absence of such triggers, the system operates in a predefined survey and monitoring mode. MMHO does not claim to replace specialized missions such as dedicated gravitational-wave observatories. Instead, it explores whether extremely large heliocentric baselines can provide complementary sensitivity to low-frequency or long-duration spacetime effects, improved parallax-based tracking of near-Sun objects, and earlier orbit refinement for poorly observed asteroids. The concept emphasizes scale, geometry, and continuous ranging over ultra-precise local instrumentation. This work is released as a conceptual preprint to invite technical critique, feasibility analysis, and further modeling. All parameters are order-of-magnitude estimates, and no claim is made regarding near-term implementation or agency endorsement.
Amsal Khan (Mon,) studied this question.