Jonathan Grzymisch

European Space Agency | ESA · Guidance, Navigation and Control Systems

The tilt-to-length coupling during the LISA Pathfinder mission has been numerically and analytically modeled for particular time spans. In this work, we investigate the long-term stability of the coupling coefficients of this noise. We show that they drifted slowly (by 1 μm / rad and 6 × 10 − 6 in 100 days) and were strongly correlated to temperatu...

We present an in-depth analysis of the LISA Pathfinder differential acceleration performance over the entire course of its science operations, spanning approximately 500 days. We find: (1) The evolution of the Brownian noise that dominates the acceleration amplitude spectral density (ASD), for frequencies f≳1 mHz, is consistent with the decaying pr...

The tilt-to-length coupling during the LISA Pathfinder mission has been numerically and analytically modeled for particular timespans. In this work, we investigate the long-term stability of the coupling coefficients of this noise. We show that they drifted slowly (by 1\,$\mu$m/rad and 6$\times10^{-6}$ in 100 days) and strongly correlated to temper...

A precise characterization of the magnetic properties of LISA Pathfinder free falling test-masses is of special interest for future gravitational wave observatory in space. Magnetic forces have an important impact on the instrument sensitivity in the low frequency regime below the millihertz. In this paper we report on the magnetic injection experi...

LISA Pathfinder was a mission designed to test key technologies required for gravitational wave detection in space. Magnetically driven forces play a key role in the instrument sensitivity in the low-frequency regime, which corresponds to the measurement band of interest for future space-borne gravitational wave observatories. Magnetic-induced forc...

Electrostatic force actuation is a key component of the system of geodesic reference test masses (TM) for the LISA orbiting gravitational wave observatory and in particular for performance at low frequencies, below 1 mHz, where the observatory sensitivity is limited by stray force noise. The system needs to apply forces of order 10−9 N while limiti...

The (LPF) mission successfully demonstrated the feasibility of the technology needed for the future space borne gravitational wave observatory LISA. A key subsystem under study was the laser interferometer, which measured the changes in relative distance in between two test masses (TMs). It achieved a sensitivity of 32.0 − 1.7 + 2.4 fm / Hz , which...

This article presents an approach to drag-free and attitude control for the laser interferometer space antenna (LISA) space mission, based on a constrained decoupling $H_{\infty}$ approach. LISA will be a space-based gravitational wave observatory, which is expected to be launched by the European Space Agency (ESA) in 2034. The LISA concept consi...

We present a study of the tilt-to-length coupling noise during the LISA Pathfinder mission and how it depended on the system’s alignment. Tilt-to-length coupling noise is the unwanted coupling of angular and lateral spacecraft or test mass motion into the primary interferometric displacement readout. It was one of the major noise sources in the LIS...

We present a study of the tilt-to-length coupling noise during the LISA Pathfinder mission and how it depended on the system's alignment. Tilt-to-length coupling noise is the unwanted coupling of angular and lateral spacecraft or test mass motion into the primary interferometric displacement readout. It was one of the major noise sources in the LIS...

The LISA (Laser Interferometer Space Antenna) mission is one of the most challenging endeavours to be undertaken by ESA whose objective is to study gravitational waves. The mission consists of three identical spacecraft in a triangular formation, with an inter-satellite distance of 2.5 million km, flying in a heliocentric orbit. Each spacecraft con...

The JUICE - JUpiter ICy moons Explorer – mission is the first large-class mission in ESA's Cosmic Vision 2015-2025 programme. Planned for launch in 2023 and arrival at Jupiter in 2031, it will spend at least three years making detailed observations of the giant gaseous planet Jupiter and three of its largest moons, Ganymede, Callisto and Europa, th...

LISA (Laser Interferometer Space Antenna) is a space mission, under study by the European Space Agency (ESA) and other institutions, with the objective of detecting, observing, and measuring gravitational waves. It consists of a triangle constellation of three spacecraft connected through bidirectional laser links to measure gravitational waves by...

A comprehensive summary of the measurements made to characterize test-mass charging due to the space environment during the LISA Pathfinder mission is presented. Measurements of the residual charge of the test mass after release by the grabbing and positioning mechanism show that the initial charge of the test masses was negative after all releases...

A comprehensive summary of the measurements made to characterize test mass charging due to the space environment during the LISA Pathfinder mission is presented. Measurements of the residual charge of the test mass after release by the grabbing and positioning mechanism, show that the initial charge of the test masses was negative after all release...

In a previous article [1], we have reported on the first subpicometer interferometer flown in space as part of ESA’s LISA Pathfinder mission, and have shown the residual sensor noise to be on the level of 32.0−1.7+2.4 fm/Hz. This review provides a deeper and more complete overview of the full system and its interferometric mission performance under...

We present an in depth analysis of the transient events, or glitches, detected at a rate of about one per day in the differential acceleration data of LISA Pathfinder. We show that these glitches fall in two rather distinct categories: fast transients in the interferometric motion readout on one side, and true force transient events on the other. T...

This paper presents a Model Predictive Control (MPC) design for the test mass release phase of the LISA space mission. LISA is a gravitational wave observatory consisting of a triangular constellation of three spacecraft. The gravitational waves are detected by measuring the relative distance between free falling test masses by means of a laser int...

LISA is a space-based gravitational wave observatory under study and prototyping by the European Space Agency and other institutions/companies. It consists in a triangular constellation of three spacecraft traveling in heliocentric orbits, connected through bi-directional laser links in order to detect/measure gravitational waves by means of interf...

We report on the first subpicometer interferometer flown in space. It was part of ESA’s Laser Interferometer Space Antenna (LISA) Pathfinder mission and performed the fundamental measurement of the positional and angular motion of two free-falling test masses. The interferometer worked immediately, stably, and reliably from switch on until the end...

LISA Pathfinder is a technology demonstrator space mission, aimed at testing key technologies for detecting gravitational waves in space. The mission is the precursor of LISA, the first space gravitational waves observatory, whose launch is scheduled for 2034. The LISA Pathfinder scientific payload includes two gravitational reference sensors (GRSs...

LISA Pathfinder (LPF) has been a space-based mission designed to test new technologies that will be required for a gravitational wave observatory in space. Magnetically driven forces play a key role in the instrument sensitivity in the low-frequency regime (mHz and below), the measurement band of interest for a space-based observatory. The magnetic...

LISA Pathfinder (LPF) has been a space-based mission designed to test new technologies that will be required for a gravitational wave observatory in space. Magnetically driven forces play a key role in the instrument sensitivity in the low-frequency regime (mHz and below), the measurement band of interest for a space-based observatory. The magnetic...

The Laser Interferometer Space Antenna Pathfinder (LPF) main observable, labeled Δg, is the differential force per unit mass acting on the two test masses under free fall conditions after the contribution of all non-gravitational forces has been compensated. At low frequencies, the differential force is compensated by an applied electrostatic actua...

We present two novel methods, tested by LISA Pathfinder, to measure the gravitational constant G for the first time in space. Experiment 1 uses electrostatic suspension forces to measure a change in acceleration of a test mass due to a displaced source mass. Experiment 2 measures a change in relative acceleration between two test masses due to a sl...

The zodiacal dust complex, a population of dust and small particles that pervades the solar system, provides important insight into the formation and dynamics of planets, comets, asteroids, and other bodies. We present a new set of data obtained from direct measurements of momentum transfer to a spacecraft from individual particle impacts. This tec...

We report on the results of the LISA Pathfinder (LPF) free-fall mode experiment, in which the control force needed to compensate the quasistatic differential force acting on two test masses is applied intermittently as a series of “impulse” forces lasting a few seconds and separated by roughly 350 s periods of true free fall. This represents an alt...

We report on the results of the LISA Pathfinder (LPF) free-fall mode experiment, in which the control force needed to compensate the quasistatic differential force acting on two test masses is applied intermittently as a series of "impulse" forces lasting a few seconds and separated by roughly 350 s periods of true free fall. This represents an alt...

LISA Pathfinder (LPF) was a technology pioneering mission designed to test key technologies required for gravitational wave detection in space. In the low frequency regime (milliHertz and below), where space-based gravitational wave observatories will operate, temperature fluctuations play a crucial role since they can couple into the interferometr...

LISA Pathfinder (LPF) was a technology pioneering mission designed to test key technologies required for gravitational wave detection in space. In the low frequency regime (milliHertz and below), where space-based gravitational wave observatories will operate, temperature fluctuations play a crucial role since they can couple into the interferometr...

The LISA Pathfinder (LPF) mission has demonstrated the ability to limit and measure the fluctuations in acceleration between two free falling test masses down to sub-femto-g levels. One of the key elements to achieve such a level of residual acceleration is the drag free control. In this scheme the spacecraft is used as a shield against any externa...

LISA Pathfinder (LPF) was a technology pioneering mission designed to test key technologies required for gravitational wave detection in space. In the low frequency regime (milli-Hertz and below), where space-based gravitational wave observatories will operate, temperature fluctuations play a crucial role since they can couple into the interferomet...

The science operations of the LISA Pathfinder mission have demonstrated the feasibility of sub-femto-g free fall of macroscopic test masses necessary to build a gravitational wave observatory in space such as LISA. While the main focus of interest, i.e., the optical axis or the x-axis, has been extensively studied, it is also of great importance to...

Non-recurrent short-term variations of the galactic cosmic-ray (GCR) flux above 70 MeV n−1 were observed between 2016 February 18 and 2017 July 3 on board the European Space Agency LISA Pathfinder (LPF) mission orbiting around the Lagrange point L1 at 1.5 × 106 km from Earth. The energy dependence of three Forbush decreases is studied and reported...

Since the 2017 Nobel Prize in Physics was awarded for the observation of gravitational waves, it is fair to say that the epoch of gravitational wave astronomy (GWs) has begun. However, a number of interesting sources of GWs can only be observed from space. To demonstrate the feasibility of the Laser Interferometer Space Antenna (LISA), a future gra...

The science operations of the LISA Pathfinder mission has demonstrated the feasibility of sub-femto-g free-fall of macroscopic test masses necessary to build a LISA-like gravitational wave observatory in space. While the main focus of interest, i.e. the optical axis or the $x$-axis, has been extensively studied, it is also of interest to evaluate t...

The Space Technology 7 Disturbance Reduction System (ST7-DRS) is a NASA technology demonstration payload that operated from January 2016 through July 2017 on the European Space Agency’s (ESA) LISA Pathfinder spacecraft. The joint goal of the NASA and ESA missions was to validate key technologies for a future space-based gravitational wave observato...

The Space Technology 7 Disturbance Reduction System (ST7-DRS) is a NASA technology demonstration payload that operated from January 2016 through July of 2017 on the European Space Agency's LISA Pathfinder spacecraft. The joint goal of the NASA and ESA missions was to validate key technologies for a future space-based gravitational wave observatory...

The LISA Pathfinder charge management device was responsible for neutralizing the cosmic-ray-induced electric charge that inevitably accumulated on the free-falling test masses at the heart of the experiment. We present measurements made on ground and in flight that quantify the performance of this contactless discharge system which was based on ph...

The LISA Pathfinder charge management device was responsible for neutralising the cosmic ray induced electric charge that inevitably accumulated on the free-falling test masses at the heart of the experiment. We present measurements made on ground and in-flight that quantify the performance of this contactless discharge system which was based on ph...

LISA Pathfinder (LPF) was a European Space Agency mission with the aim to test key technologies for future space-borne gravitational-wave observatories like LISA. The main scientific goal of LPF was to demonstrate measurements of differential acceleration between free-falling test masses at the sub-femto-g level, and to understand the residual acce...

LISA Pathfinder is a technology demonstrator mission that was funded by the European Space Agency and that was launched on December 3, 2015. LISA Pathfinder has been conducting experiments to demonstrate key technologies for the gravitational wave observatory LISA in its operational orbit at the L1 Lagrange point of the Earth–Sun system until final...

Galactic cosmic-ray (GCR) energy spectra observed in the inner heliosphere are modulated by the solar activity, the solar polarity and structures of solar and interplanetary origin. A high counting rate particle detector (PD) aboard LISA Pathfinder (LPF), meant for subsystems diagnostics, was devoted to the measurement of galactic cosmic-ray and so...

In the months since the publication of the first results, the noise performance of LISA Pathfinder has improved because of reduced Brownian noise due to the continued decrease in pressure around the test masses, from a better correction of noninertial effects, and from a better calibration of the electrostatic force actuation. In addition, the avai...

The LISA Pathfinder radiation monitor made in situ measurements of the interplanetary charged-particle environment that was responsible for charging the isolated test masses at the heart of the experiment. We describe this bespoke radiation monitor and present measurements which show a gradual 40% increase in count rate coinciding with the declinin...

We report on the performance of the capacitive gap-sensing system of the Gravitational Reference Sensor on board the LISA Pathfinder spacecraft. From in-flight measurements, the system has demonstrated a performance, down to 1 mHz, that is ranging between 0.7 and 1.8 aF Hz−1/2. That translates into a sensing noise of the test mass motion within 1.2...

We report on electrostatic measurements made on board the European Space Agency mission LISA Pathfinder. Detailed measurements of the charge-induced electrostatic forces exerted on free-falling test masses (TMs) inside the capacitive gravitational reference sensor are the first made in a relevant environment for a space-based gravitational wave det...

LISA Pathfinder satellite was launched on 3 December 2015 toward the Sun-Earth first Lagrangian point (L1) where the LISA Technology Package (LTP), which is the main science payload, will be tested. LTP achieves measurements of differential acceleration of free-falling test masses (TMs) with sensitivity below 3 × 10⁻¹⁴ m s⁻² Hz-1/2 within the 1-30...

The Lisa Path�nder (LPF) mission is a technology demonstrator for a gravity-wave observatory carrying the most critical technologies needed to measure gravity waves in space. These include an optical interfer- ometer to measure very precisely the distance between two free- oating test masses, one in drag-free motion and one electro-statically contr...

We report the first results of the LISA Pathfinder in-flight experiment. The results demonstrate that two free-falling reference test masses, such as those needed for a space-based gravitational wave observatory like LISA, can be put in free fall with a relative acceleration noise with a square root of the power spectral density of 5.2±0.1 fm s^{-2...

In-orbit rendezvous is a key enabling technology for many space missions that already enjoys significant heritage. However, complex hardware is generally required in order to measure the relative range. Achieving rendezvous employing only bearing/angle measurements would simplify the relative navigation hardware currently required, increasing robus...

Employing only bearing/angular measurements for navigation during the far to medium range rendezvous with a non-cooperative target has several advantages with respect to directly measuring the range using active sensors such as RADAR or LIDAR. Angular measurements can be acquired using simple sensors such as a single optical camera, significantly r...

A study was conducted to present an alternative analytic expression for an optimal observability objective that could be used to maximize observability for any given initial trajectory. The proposed objective function was more versatile due to its simple form and could easily be included within a higher-level trajectory optimization scheme. This si...

Orbital debris is a growing problem threatening Low Earth Orbit (LEO) assets that provide foundational services and data critical in modern society. The debris population is especially concentrated in popular orbits such as Sun Synchronous Orbit (SSO). Active Debris Removal (ADR) and On-Orbit Servicing (OOS) offer a means to reverse the threat of d...

This paper provides an analytical derivation of the observability conditions for in-orbit bearings-only navigation that can also be used to solve for the conditions under which unobservable maneuvers occur. The derivation is performed in a rigorous yet relatively simple manner by attempting to solve for the initial conditions in a discrete formulat...

In-orbit rendezvous is a key enabling technology for many space missions including in-orbit assembly, servicing, refuelling, inspection, active de-orbiting as well as planetary exploration and return. Even though there exists significant heritage on this topic, complex hardware is generally required on both the chaser and the target spacecraft in o...

In-orbit rendezvous is a key enabling technology for many space missions. Implementing it employing only bearing measurements would simplify the relative navigation hardware currently required, increasing robustness and reliability by reducing complexity, launch mass and cost. The problem of bearings-only navigation has been studied intensively by...

The Space Flight Laboratory (SFL) at the University of Toronto Institute for Aerospace Studies (UTIAS) is developing enabling technologies in collaboration with the University of Calgary for future precise formation flying missions. These technologies will be validated on two nanosatellites under development as part of SFL's Canadian Advanced Nanos...

The Space Flight Laboratory (SFL) at the University of Toronto Institute for Aerospace Studies (UTIAS) is developing enabling technologies for future precise formation flying missions. These technolo- gies will be validated on an upcoming mission under development as part of SFL’s Canadian Advanced Nanospace eXperiment (CanX) program. The CanX-4 Ca...

The farside gravity field of the Moon has so far be en inferred through model-fitting based on Earth ob servations of farside entry and exit points of past lunar orbiter s. The gravity model of the farside - currently 5 t o 10 times less precise than the near-side model - could be refined significantly if two low-altitude satellites were to measure...