Author 1: Kuzin S.P.  (INASAN)

Title: Calculating the orbits of the DORIS satellite constellation

Abstracts:
In this work, the orbits of six DORIS satellites were determined over a three-year time interval from 2022.0 to 2025.0. Calculations were performed for the Cryosat2, Jason3, Saral, Sentinel3a, Sentinel3b and Sentinel6a satellites based on DORIS RINEX measurement processing. The orbit determination accuracy was assessed both by internal convergence and by comparison with orbits obtained by other DORIS data analysis centers.

The root-mean-square errors in calculating the radial velocity between satellites and ground stations vary within the range of 0.35 mm/s to 0.40 mm/s. The accuracy of daily orbit overlap by internal convergence varies within the range of 1.97 cm to 3.41 cm in the vertical direction, 4.90 cm to 7.71 cm in the transverse direction, and 3.19 cm to 5.26 cm in the longitudinal direction of the satellite motion. The root-mean-square errors of orbit determination for the five satellites (Cryosat2, Saral, Sentinel3a, Sentinel3b and Sentinel6a satellites) range from 1.87 cm to 2.55 cm in the vertical direction, 3.48 cm to 7.11 cm in the transverse direction, and 3.37 cm to 5.62 cm in the longitudinal direction in relation to the POE-F orbits of the CNES-SSALTO analysis center.

For the Jason3 satellite, the root-mean-square errors are 9.66 cm, 9.30 cm, and 36.26 cm for the vertical, transverse, and longitudinal directions, respectively. Such elevated error values require additional studies for the Jason3 satellite.

Author 2: Shematovich V.I. (INASAN)

Title:Astrobiological potential of asteroids from spacecraft missions to asteroids

Abstracts:
The talk discusses a set of new findings on the physical properties of small Solar System bodies obtained in recent spacecraft missions to asteroids.

It will review selected highlights from JAXA’s Hayabusa2 mission to asteroid Ryugu (1999 JU3 Ryugu) and NASA’s OSIRIS-REx mission to asteroid Bennu (101955 Bennu). The first laboratory results on the returned samples indicate a significant astrobiological potential of asteroids as mobile carriers of complex abiotic organic matter in the Solar System