Warning of asteroids approaching Earth from the sunward direction using two Earth-leading heliocentric orbiting telescopes

Ground-based optical telescopes suffer from a blind zone surrounding the Sun. In this article, two telescopes were proposed to be deployed on an Earth‑leading heliocentric orbit approximately 10 million kilometers ahead of the Earth to warn of asteroids approaching Earth from the sunward direction. Considering the initial orbit determination, a discovery model for asteroids was established. Based on Granvik's impactor and near-Earth asteroid (NEA) populations, the warning efficiency of the Earth‑leading heliocentric orbiting telescopes for asteroids approaching Earth from the sunward direction was simulated. The simulation results show that under the designed search strategy, with a limiting apparent magnitude of 24, the warning efficiency of two Earth‑leading heliocentric orbiting telescopes for impactors and NEAs approaching Earth from the sunward direction reaches 99.0% and 94.3% (with 0.4% and 0.8% uncertainty, respectively) within 6 years, which is 95.8% and 57.5% (with 0.7% and 1.7% uncertainty, respectively) for one telescope deployed on an Earth‑leading heliocentric orbit and 22.1% (with 1.5% uncertainty) for two telescopes deployed on a Sun-Earth L1 orbit. Earth‑leading heliocentric orbiting telescopes thus provide a possible option to cover the blind zone of ground-based optical telescopes. •ELHO was used to cover the blind zone of ground-based optical telescopes.•“Discovery” was defined by initial orbit determination condition.•Survey telescope and follow-up telescope work cooperatively to discover asteroids.•Warning efficiency for asteroids approaching Earth from the sunward direction is more than 94%.