Astrodynamical Space Test of Relativity using Optical Devices I (ASTROD I) - Mission Overview

TL;DR

ASTROD I is a space mission designed to test Einstein's theory of relativity with unprecedented precision using optical devices, aiming to improve measurements of gravitational parameters and explore fundamental physics.

Contribution

It introduces the ASTROD I mission concept, detailing its goals, technological basis, and its role within a series of missions to test relativity and gravitational phenomena.

Findings

Enhanced accuracy in testing General Relativity

Improved measurements of solar system parameters

Potential detection of low-frequency gravitational waves

Abstract

ASTROD I is the first planned space mission in a series of ASTROD missions for testing relativity in space using optical devices. The main aims are: (i) to test General Relativity with an improvement of three orders of magnitude compared to current results, (ii) to measure solar and solar system parameters with improved accuracy, (iii) to test the constancy of the gravitational constant and in general to get a deeper understanding of gravity. The first ideas for the ASTROD missions go back to the last century when new technologies in the area of laser physics and time measurement began to appear on the horizon. ASTROD is a mission concept that is supported by a broad international community covering the areas of space technology, fundamental physics, high performance laser and clock technology and drag free control. While ASTROD I is a single-spacecraft concept that performes measurements with pulsed laser ranging between the spacecraft and earthbound laser ranging stations, ASTROD-GW is planned to be a three spacecraft mission with inter-spacecraft laser ranging. ASTROD-GW would be able to detect gravitational waves at frequencies below the eLISA/NGO bandwidth. As a third step Super-ASTROD with larger orbits could even probe primordial gravitational waves. This article gives an overview on the basic principles especially for ASTROD I.