An Addition to the Suite of Geodetic Satellites Supporting the ITRF: LARES-2

Abstract

Geodetic network infrastructure has evolved with increasing pace the past decade with remarkable additions of modern hardware, replacing aging, '80s vintage equipment throughout the globe. The Satellite Laser Ranging-SLR network is the slowest in making changes designed and planned more than a decade ago [Pearlman et al., 2019a]. This is in part due to the voluntary nature of establishing such installations and to a greater part the high cost and limited availability of the one-of-a-kind equipment. NASA, partners and international agencies, embarked on updates with standardization will help in the long term [Merkowitz et al., McGarry et al., Wilkinson, et al., 2019]. SLR needs more than updating the network to deliver the accuracy required today. New "targets" must also be used that support mm-accuracy. LAGEOS was conceived and built in the early '70s with a ~5 mm accuracy in mind [Pearlman et al., 2019b]. This limitation forced analysts to develop approaches of data analysis to ensure that even with such data one can reach the required 1-mm accuracy [Luceri et al., 2019]. Along with the network updates a parallel effort was thus initiated to modernize the space segment as well. Initially with the design and launch of LARES in 2012 [Pavlis et al., 2015] and following that, the design of LARES-2 [Ciufolini et al., 2017, Paolozzi et al., 2019], which was successfully launched on July 13, 2022 [https://www.nature.com/articles/d41586-022-02034-x]. The new mm-accurate target was quickly acquired first by the Matera, Italy station only three days after launch and although very early in the mission, the data were of remarkably high quality and insignificant bias. This prompted a quick evaluation and a test inclusion of this target in the limited list of SLR targets supporting the ITRF development. With an orbit nearly identical to LAGEOS (with supplementary inclination), taking full advantage of all the appropriate models designed and applied to LAGEOS, we achieved 7-day orbital fits of 3-5 mm even without a tuned target signature correction! We will present an overview of the initial analysis of LARES-2 data focusing on comparing them to contemporaneously taken LAGEOS data, we will show results from our initial inclusion of LARES-2 in developing ILRS products for ITRF development and discuss the ILRS plans for its full integration. Ciufolini, Phys. Rev. Lett (1986) Ciufolini, Int. J. of Mod. Phys. A (1989) Pearlman et al., J Geod 93, 2161-2180 (2019a). https://doi.