Characterization of the Candidate Landing Region for Tianwen‐1—China's First Mission to Mars

Abstract

This paper presents our efforts to characterize the candidate landing region (109°–133°E, 23°–30°N) for Tianwen‐1, China's first mission to Mars, in terms of engineering safety and scientific significance. Topographic analysis reveals that the region has a low elevation around −4,230 m, and 98% of the region have slopes smaller than 8°. The geomorphological mapping and analysis show that the region has an average crater density of about 28 craters (≥200 m in diameter) per 100 square kilometers, with several clusters of high crater densities distributed around the center of the region. There are also pitted cones distributed mainly in the southern part of the region, with a density of approximately 6.6 cones per 100 square kilometers in specific local areas. The region has rock abundances ranging from 1% to 23%, with local clusters of low and high rock abundances. The region comprises four main geological units, including a lowland unit formed in the Late Hesperian and a volcanic unit formed in the Amazonian and Hesperian period. Their specific surface ages are estimated through the analysis of crater size‐frequency distribution. Combining the engineering constraints on surface slopes, crater density, cone density, and rock abundance, a hazard map of the candidate landing region is generated for landing site evaluation and safety assessment. Based on the results, we further discuss the potential scientific outcomes from the exploration in this region. The findings will be helpful for the mission planning and maximization of the scientific return from Tianwen‐1, and complement existing Martian scientific research.

Landing Site Selection and Characterization of Tianwen‐1 (Zhurong Rover) on Mars

“…The geometric accuracies of the generated image mosaic and DEM were evaluated by comparison with reference data. Mars Reconnaissance Orbiter (MRO) Context Camera (CTX) images were used to generate an image mosaic (6 m/pixel) covering the same area (Wu et al., 2021). The CTX images were map‐projected based on the Mars Orbiter Laser Altimeter (MOLA) DEM and mosaicked by using our in‐house photogrammetric software (Hu & Wu, 2019).…”

“…The landing area of Tianwen‐1 (Zhurong rover) was mapped as a Late Hesperian lowland (lHl) unit (Tanaka et al., 2014) with an estimated age of 3.34 Ga (Wu et al., 2021). Previous studies have indicated that the lHl unit is mainly composed of Vastitas Borealis Formation (VBF) materials, which might have originated from fluvial, lacustrine or marine sediments (Carr & Head, 2019; Ivanov & Hiesinger, 2020; Kreslavsky & Head, 2002).…”

“…The landing site selection process for Zhurong included several stages. In the first stage, a global search process was conducted on the Martian surface to identify suitable regions that met the engineering constraints, including adequate solar illumination for generating power and warmth, lower elevation for a thicker atmosphere and longer deceleration time, and a flat terrain surface for safer landing (Dong et al., 2019; Wu et al., 2021). Three candidate landing areas located within 5°–30°N were identified.…”

“…The area in Chryse Planitia was excluded owing to its relatively rough terrain surface and complicated geomorphological features. A local area in southern Utopia Planitia was further selected as the target landing area (109°–133°E and 23°–30°N; the cyan polygon in Figure 1) for its optimal combination of the abovementioned factors (Wu et al., 2021). In the third stage, the target landing area was examined in detail in terms of engineering safety and scientific importance, and two local regions within the target landing area were shortlisted, with one as the main landing region (approximately 180 × 70 km in size centered at 110.318°E, 24.748°N; the red polygon in Figure 1) and the other as a backup landing region (centered at 131.626°E, 26.467°N with similar size).…”

Layered Ejecta Craters in the Candidate Landing Areas of China's First Mars Mission (Tianwen‐1): Implications for Subsurface Volatile Concentrations

“…It is composed of an orbiter, a lander, and a rover. Given the rover's requirement for touchdown safety and mobility, two candidate landing areas were selected for the Mars exploration mission in the latitude range of 5-30°N (Ye et al, 2017;B. Wu, Dong, et al, 2021): the southern Utopia-Isidis Planitia (SUIP) and southern Chryse Planitia (SCP; Figure 2).…”