This paper develops a framework that models and optimizes the operations of complex on-orbit servicing infrastructures involving one or more servicers and orbital depots to provide multiple types of services to a fleet of geostationary satellites. The proposed method extends the state-of-the-art space logistics technique by addressing the unique challenges in on-orbit servicing applications and integrates

Operating Earth-observing satellites requires efficient planning methods that coordinate activities of multiple spacecraft. The satellite task-planning problem entails selecting actions that best satisfy mission objectives for autonomous execution. Task scheduling is often performed by human operators assisted by heuristic or rule-based planning tools. This approach does not efficiently scale to multiple

Blunt-nosed launch vehicles featuring large nose-cone angles experience high levels of pressure fluctuations over the payload region at transonic Mach numbers due to shock-wave/boundary-layer interactions. The main cause for this phenomenon appears to be flow instability associated with separated flow and formation of a vortex pair. Interactions between the induced velocity of the vortex pair and oncoming

The energetic electrostatic analyzer has been developed to act as a miniaturized, rugged, and low-cost instrument capable of providing in situ measurements of ion or electron energy and subsequent derived density, temperature, and spacecraft potential. We present laboratory calibration results using a magnetically filtered low-Earth-orbit plasma simulator to quantify the effects of spacecraft charge

This paper presents simulation models and an analysis of the hovering capability of an electrostatic spacecraft around a small celestial body. The hovering capabilities of an electrically actuated spacecraft are evaluated by combining orbital dynamics analysis with 3-D fully kinetic particle-in-cell simulations of asteroid/spacecraft interactions with the solar-wind plasma. The zero-velocity curves

Numerous missions are being proposed which involve multiple spacecraft operating in close proximity in harsh charging environments. In such missions, the ability to sense the electrostatic potential on a nearby object is critical to prevent harmful electrostatic discharges or to leverage Coulomb interactions for relative motion control. The electron method is one such technique for touchless potential

A range of upcoming missions propose to rendezvous in high Earth orbits, including the geostationary orbit region. This region is known to periodically experience high levels of electrostatic charging, which can result in perturbing intercraft forces and torques during close-proximity operations on the order of tens of meters. A range of proximity operations with a nonoperational target are modeled

Outgassing from spacecraft materials is known to degrade performance of various components, of which particularly affected are cold and cryogenic surfaces. For those surfaces that suffer from performance losses due to molecular contamination, it is important to assess the contamination levels at an early stage of a project to apply necessary risk mitigation and/or risk avoidance. The focus of this

Ignition overpressure (IOP) is a principal dynamic load experienced by a launch vehicle during liftoff. The IOP arises due to the sudden ignition of the solid rocket boosters (SRBs) of a launch vehicle. The present work attempts to simulate the ignition of an SRB with an impulsively started supersonic Md=2.0 jet generated using a quick-open valve. High-speed schlieren flow visualization is used to

DALBIT-1, a miniature-sized, fully integrated, Earth-based lander test bed was designed and developed for the vertical takeoff and vertical landing flight demonstration. Mission and design requirements and vehicle subsystems were selected to accommodate the vertical takeoff and vertical landing preliminary flight demonstration. Subsystems, including the propulsion system, structure, avionics, and ground

This paper proposes a novel machine learning (ML) gyro calibration method that can achieve higher-accuracy gyro calibration and attitude estimation than the classical extended Kalman filter (EKF) approach when high-accuracy measurements are unavailable. The gyro calibration process is modeled as a time-series problem based on the standard EKF output. Then, a designed ML model is trained by the collected

Placing a small satellite into a high-inclination orbit with respect to the ecliptic plane may offer a low-cost option for opportunistic and targeted observations of the polar regions of the Sun or the zodiacal dust cloud of the solar system. In this paper, dynamical systems theory and hybrid optimization techniques are integrated into a cohesive framework to design low-thrust trajectories for a small

Retropropulsion, a deceleration technique where the thrust is directed along the flight path, is the driving technology for vertically landing, reusable launchers. Experiments, which are indispensable for the full comprehension of retropropulsion flows, pose serious challenges to the operability of wind tunnels and interpretation of these subscale experiments. The key factors to facilitate meaningful

Journal of Spacecraft and Rockets, Ahead of Print.

Journal of Spacecraft and Rockets, Ahead of Print.

Carbon/carbon (C/C) structures are widely considered for space thermal protection systems (TPSs), being able to withstand critical reentry conditions thanks to an excellent thermal stability. In low-Earth-orbit long-time missions, however, the TPS effectiveness is significantly lowered due to the surfaces’ prolonged staying within the harsh space environment. In particular, the detrimental oxidation

Journal of Spacecraft and Rockets, Ahead of Print.

The Small Satellite Dynamics Testbed (SSDT) at the Jet Propulsion Laboratory offers infrastructure that supports small satellite guidance and control testing in a relevant dynamics environment while constrained by the gravity of Earth. One of the testing environments of the SSDT is its planar air-bearing platform, which has two lateral and one rotational degrees of freedom. This paper details the new

An optimal real-time neural-network-based controller for an on-orbit service mission is proposed. The problem can be mathematically formulated as a complex optimal control problem due to the coupling nature of the orbit, the attitude, and the manipulator of the chaser spacecraft. A hierarchical optimization procedure is developed to efficiently solve the problem by recursively applying three optimization

Journal of Spacecraft and Rockets, Ahead of Print.

The effect of microcracking in the phenolic matrix of a three-dimensional woven thermal protection system (TPS) and resulting material stiffness reduction was studied via a comparison of finite element results from linear and iterative linear analyses. A dual-layer continuous dry weave material with a low-density phenolic resin matrix has been developed for use in extreme environments. Because of high

Journal of Spacecraft and Rockets, Ahead of Print.

Before the successful Exploration Flight Test 1 (EFT-1) flight test in December 2014, the Orion EFT-1 Heat Shield suffered from two major certification challenges: First, the mechanical properties used in the design were not evident in the flight hardware, and, second, the flight article itself cracked in several locations during fabrication. These events motivated the Orion Program to pursue an engineering-level

This paper explores the feasibility and benefits of a new way of the Phobos sample return delivery mission to a Phobos Sample Return (PSR) orbiter using the electrostatic field artificially generated in proximity to the Mars–Phobos L1 libration point. The proposed method uses the electrostatic interaction to retrieve an orbit sample container (OS) launched from Phobos. This is possibly the first discussion

During atmospheric reentry at hypersonic speed and during very-high-speed flight in the atmosphere, vehicles experience extremely high thermal loads for relatively long time. To handle this problem, classical thermal protection materials may need to be replaced with lightweight actively cooled components. This work investigates experimental film cooling of a blunt body in a supersonic high-enthalpy

High tumbling rates of uncooperative target pose strong technical challenges and collision risks that can prevent removal of the debris using contact, such as with robotic arms or capture nets. Electrostatic touchless detumbling is a promising technology that can be used to decrease the rotational velocity of an uncooperative object in geosynchronous orbit, from a safe distance. This paper demonstrates

This paper develops a flexibility management framework for space logistics mission planning under uncertainty through decision rules and multistage stochastic programming. It aims to add built-in flexibility to space architectures in the phase of early-stage mission planning. The proposed framework integrates the decision rule formulation into a network-based space logistics optimization formulation

The swerve response of spin-stabilized projectiles to the canard control problem is revisited in the present paper. The study is divided into three steps, including angle-of-attack response, velocity vector response of the projectile, and finally the swerving response. A complex deviation angle is used to describe the motion of the velocity vector of the projectile over the controlled trajectory. From

The objective of this work was to investigate a multifidelity modeling approach to accurately and efficiently predict the turbulent convective heating on hypersonic inflatable aerodynamic decelerators with both smooth and scalloped walls. A previously developed co-kriging-based multifidelity modeling approach was used to model the turbulent and laminar convective heat fluxes on smooth wall vehicles

The effect of propellant sloshing upon the stability of a liquid-propelled space vehicle in a high-g environment has been studied extensively. For a typical space vehicle with thrust vector control and a single slosh tank, the Bauer slosh danger zone is located between the vehicle center of mass and the center of percussion while ignoring effects, like aerodynamics and axial acceleration. If the slosh

The results of a parametric, numerical study of aftbody exhaust flows on a conical, airbreathing, hypersonic vehicle are presented. Three-dimensional Euler simulations were performed at Mach 9 and steered to a pitch-trimmed lift-equals-weight condition. Quasi-1-D cycle analysis was employed to model the scramjet propulsion and viscous forces were accounted for using a separate boundary-layer code.

In this paper, magnetometer-based orbit determination via the fast reconstruction of a 3-D decoupled geomagnetic field (TDGF) model is examined. For the TDGF model, the three components of the geomagnetic field vector at a certain point are calculated separately with three different independent sets of Gauss coefficients rather than one identical set. The fast reconstruction algorithm is based on a

With renewed interest in lunar exploration and the upcoming deployment of the lunar space station, the Lunar Orbital Platform-Gateway (LOP-G), a scientific community, is focusing on the design of a lander to bring people back to the lunar surface. This work focuses on optimizing two aspects of the lunar lander concurrently: the mission architecture and the vehicle design, often treated independently

Journal of Spacecraft and Rockets, Ahead of Print.

This work studies the performance of periodic orbits to observe and conduct space traffic management (STM) in cislunar space, with the aim of finding a preferable trajectory for future missions focused on detection, tracking, initial orbit estimate formation, and orbit estimate maintenance. A measure is mathematically developed to quantitatively evaluate the observation performance of a given trajectory

Since the seminal work of Daniele Mortari (“Moon-Sun Attitude Sensor,” Journal of Spacecraft and Rockets, Vol. 34, No. 3, 1997, pp. 360–364), the concept of an attitude sensor using images of illuminated celestial bodies has been pushed forward through the years. The basic idea consists of extracting two independent directions from the image of a celestial body, namely, the camera-to-planet and the

In situ atmospheric measurements are a high priority for any future Flagship mission to the Ice Giants; however, most current mission concepts only include a single atmospheric entry probe in their designs. To maximize science returns and provide redundancy at a marginal cost, different mission architecture options are explored to deliver multiple atmospheric probes to Uranus. A methodology is developed

This paper presents a methodology for the concurrent first-stage preliminary design and ascent trajectory optimization, with application to a Vega-derived light launch vehicle. The reuse as first stage of an existing upper-stage (Zefiro 40) requires a redesign of the propellant grain geometry, in order to account for the mutated operating conditions. An optimization code based on the parallel running

A mission scenario is proposed, where a large number of centimeter-scale femto-spacecraft are dispersed from a CubeSat piggyback payload on a future Mars mission. This swarm would deliver real-time massively parallel sensing throughout entry, descent, and landing with in-orbit measurements, atmospheric characterization during descent, and even surface science upon landing. Because few entry profiles

This paper presents an initial feasibility study on the use of ionic-liquid ion sources for electrostatic actuation on atmosphere-less planetary bodies. The natural surface charging of atmosphere-less planetary bodies has been studied as the cause of the transport of regolith across the surface and for electrostatic levitation of a spacecraft in proximity to small asteroids. The low magnitude of the

This work examines the problem of planet-centered orbit transfers using solar sail propulsion. Though solar sails offer unlimited ΔV, they place coupled time-dependent restrictions on thrust magnitude and direction, and the multiple objectives of an orbit transfer can make locally optimal approaches inefficient; it is therefore advantageous to use optimal control to design such trajectories. This paper

A novel magnetohydrodynamic (MHD) flow control mechanism based on the magnetic induced vortex is proposed to improve the thermal protection performance and aerodynamic performance of reentry vehicles. The magnetic field based on the polygonal coil grid is designed to obtain different vortex forms. Five Lorentz force models are constructed to reveal the MHD interaction mechanisms of the magnetic induced

A novel rigid deployable aeroshell architecture has been developed, where rigid panels with a thermal protection system layer are connected between retractable ribs. Following origami principles, an optimal fold pattern is selected and imposed on the panels to ensure efficient flat stowage during launch and repeatable deployment. The design process includes minimizing the number of folds to reduce

Journal of Spacecraft and Rockets, Ahead of Print.

This study presents the design and testing of a metallic thermal protection system (TPS) for future spaceplane vehicles. A conceptual design of the developed metallic TPS panel consisting of an outer sandwich structure, thermal insulation, inner support brackets, and a base framelike structure was redesigned from the metallic TPS panel developed by NASA. The thermal load was selected from a previous

The presence of dust in the Mars atmosphere can adversely affect heat shields of entry vehicles by enhancing erosion and increasing surface heat fluxes. However, the accuracy of numerical simulations investigating these effects is limited due to a lack of well-validated physical models of the particle phase. To address this issue, the sensitivities of computational predictions of dust-induced heating

Aerodynamic forces significantly affect spacecraft operating in very low Earth orbits, especially CubeSats with limited control authority. Six-degree-of-freedom analysis is required to assess the impact of aerodynamic forces on attitude and translational motion for missions operating in this flight regime. In this work, the flight performance of a range of CubeSats is compared in the context of a high-altitude

Thermal protection system (TPS) is one of the most important subsystems for vehicle reentry. Because of the uncertainties in thermal loads, material properties, and manufacture tolerances, the thermal response of TPS has strong randomness, which brings great challenges to the engineering design and reliability evaluation. Because the uncertain aerodynamic heating loads are stochastic processes in time

Journal of Spacecraft and Rockets, Ahead of Print.

Journal of Spacecraft and Rockets, Ahead of Print.

Space Rider is the European program proposed to develop an affordable and sustainable reusable space transportation system to enable access to and return from space. To procure a safe and accurate landing, Space Rider will use a large deployable parafoil to fly autonomously upon the landing site. The landing guidance algorithm is based on two preselected waypoints and enables the system to reach the

Journal of Spacecraft and Rockets, Ahead of Print.

A magnetically filtered oxygen plasma source has been developed and characterized for the purpose of simulating the low-Earth-orbit environment. The source uses a magnetic ring cusp geometry coupled with a transverse magnetic filter to produce a plasma stream consisting of streaming atomic oxygen ions with energy, density, and ion species composition corresponding to orbital conditions at altitudes

The work described in this paper harnesses an open-source astrodynamics engine and visualization to quantify the performance of on-board optical navigation. It introduces the Hough Circles transform as a candidate method for centroid and apparent diameter extraction. The coupled nature of the simulation enables simultaneous pointing and orbit determination with dynamic image generation, all in a realistic

The presence of parts separating from the launch vehicle (LV) during of the active part of the flight, such as the tail and interstage compartments, and payload fairing calls for the solution of the problem associated with the allocation of significant impact areas. This is a common problem in all spaceships, including the cases when recoverable and reusable first stages are used, for example, Falcon

A novel concept for the deflection of rotating asteroids is presented, based on the conversion of the asteroid rotational kinetic energy into translational kinetic energy. Such conversion is achieved using an orbital siphon, a tether-connected chain of masses, arranged vertically from the asteroid surface, which exploits the rotation of the asteroid for the delivery of mass from the asteroid to escape

To build a sustainable space transportation system for human space exploration, the design and deployment of space infrastructure, such as in situ resource utilization plants, in-orbit propellant depots, and on-orbit servicing platforms, are critical. The design analysis and trade studies for these space-infrastructure systems require the consideration of not only the design of the infrastructure elements

The thermal protection system (TPS) for spacecraft is easily damaged by various thermal and mechanical loads, which adversely affects the thermal protection performance of the system. TPS damages diagnosis is one of the most complex and challenging problems for spacecraft structural reliability. The embedded distributed optical fiber sensor can directly reflect the physical field distribution of the

An examination of aero-assisted atmospheric entry dynamics of “generic” satellites is presented rather than for space planes or trans-atmospheric vehicles, as shown by legacy and contemporary literature. Not intended to reenter the atmosphere before mission disposal operations, a generic satellite is characterized in this research by a prismatic bus structure and deployed solar panels. For all analyses

The problem of optimal guidance of a low-altitude skid-to-turn vehicle is considered. In particular, the skid-to-turn vehicle is both guided and controlled using a recently developed computational optimal guidance and control method that employs hp Gaussian quadrature collocation. First, this recently developed method is used to re-solve the optimal control problem on a shrinking horizon at constant