What does the photo of the Earth and the Moon sent back by Tianwen-1 look like? The Tianwen-1 probe took a photo of the Earth and the Moon

On July 27, the optical navigation sensor on the Tianwen-1 Mars probe developed by the China Aerospace Science and Technology Corporation took a photo 1.2 million kilometers away from the Earth, saying goodbye to its Earth-Moon home. Tianwen-1 used optical navigation sensors to image the Earth and the Moon, and obtained a clear photo of the Earth and the Moon. In this black-and-white photo, the Earth and the Moon, one large and one small, both in the shape of a crescent, accompany each other in the vast universe.

A probe in space is like a ship sailing on the vast ocean, the difference is that there is no satellite navigation system to guide it after it leaves the earth. Different from traditional radio navigation, optical autonomous navigation can acquire navigation information such as position and speed through image target recognition and feature extraction. This is also one of the important technologies that will support our country's future progress into deeper space.

Based on the precise positioning achieved through ground-based radio navigation, the research and development team of the Eighth Academy of China Aerospace Science and Technology Corporation equipped the probe with optical navigation sensors and conducted engineering verification of optical navigation methods related to deep space exploration. This optical navigation sensor is installed on the probe. It can image Mars as it flies close to Mars, use the Mars images to calculate the centroid position and apparent radius of Mars, and combine it with the estimation algorithm to obtain the real-time position and speed information of the probe relative to Mars. The Earth-Moon imaging was completed by autonomous exposure and photography of the optical navigation sensor.