Advancing Tests of Relativistic Gravity via Laser Ranging to Phobos

Abstract

Phobos Laser Ranging (PLR) is a concept for a space mission designed to advance tests of relativistic gravity in the solar system. PLR's primary objective is to measure the curvature of space around the Sun, represented by the Eddington parameter $\gamma$, with an accuracy of two parts in $10^7$, thereby improving today's best result by two orders of magnitude. Other mission goals include measurements of the time-rate-of-change of the gravitational constant, $G$ and of the gravitational inverse square law at 1.5 AU distances--with up to two orders-of-magnitude improvement for each. The science parameters will be estimated using laser ranging measurements of the distance between an Earth station and an active laser transponder on Phobos capable of reaching mm-level range resolution. A transponder on Phobos sending 0.25 mJ, 10 ps pulses at 1 kHz, and receiving asynchronous 1 kHz pulses from earth via a 12 cm aperture will permit links that even at maximum range will exceed a photon per second. A total measurement precision of 50 ps demands a few hundred photons to average to 1 mm (3.3 ps) range precision. Existing satellite laser ranging (SLR) facilities--with appropriate augmentation--may be able to participate in PLR. Since Phobos' orbital period is about 8 hours, each observatory is guaranteed visibility of the Phobos instrument every Earth day. Given the current technology readiness level, PLR could be started in 2011 for launch in 2016 for 3 years of science operations. We discuss the PLR's science objectives, instrument, and mission design. We also present the details of science simulations performed to support the mission's primary objectives.

25 pages, 10 figures, 9 tables

References in corpus (5)

• Wilkinson Microwave Anisotropy Probe (WMAP) Three Year Results: Implications for Cosmology
• The Confrontation between General Relativity and Experiment
• Infrared-modified gravities and massive gravitons
• INPOP08, a 4-D planetary ephemeris: From asteroid and time-scale computations to ESA Mars Express and Venus Express contributions
• Space-based tests of gravity with laser ranging

Cited by in corpus (23)

• An exact Schwarzschild-like solution in a bumblebee gravity model
• Lunar laser ranging: the millimeter challenge
• Tests of Gravity with Future Space-Based Experiments
• The $H_0$ tension: $\Delta G_N$ vs. $\Delta N_{\mathrm{eff}}$
• 2PN Light Propagation in the Scalar-Tensor Theory: an $N$-Point-Masses Case
• Laser and Radio Tracking for Planetary Science Missions - A Comparison
• Diffraction of electromagnetic waves by an extended gravitational lens
• Novel constraints on fifth forces and ultralight dark sector with asteroidal data
• Scalar-tensor propagation of light in the inner solar system at the millimetric level
• Space-Time Reference with an Optical Link
• New perturbative method for solving the gravitational N-body problem in the general theory of relativity
• Constraining the Nordtvedt parameter with the BepiColombo Radioscience experiment
• Propagation and Estimation of the Dynamical Behaviour of Gravitationally Interacting Rigid Bodies
• Accelerating relativistic reference frames in Minkowski space-time
• Space-time Dynamics Estimation from Space Mission Tracking Data
• Prospects for Mapping Temporal Height Variations of the Seasonal CO2 Snow/Ice Caps at the Martian Poles by Co-registration of MOLA Profiles
• Effects of standard and modified gravity on interplanetary ranges
• A simple superconductor quantum interference device for testing gravity
• Lunar Laser Ranging with High-Power CW Lasers
• Testing the Strong Equivalence Principle with spacecraft ranging towards the nearby Lagrangian points
• A uniform treatment of the orbital effects due to a violation of the Strong Equivalence Principle in the gravitational Stark-like limit
• Astronomical relativistic reference systems with multipolar expansion: the global one
• Astrometric tests of General Relativity in the Solar System: mathematical and computational scenarios