Vaios Lappas

Prof. Vaios Lappas

Department of Aerospace Science & Technology, National & Kapodistrian University of Athens, 157 72 Athens, Greece
orcid

Research Focus & Metrics

Academic Career Length

19Years (2008-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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16 June 2025 in Aerospace
Verified
Journal Article
Open access
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Konstantinos-Panagiotis BouzoukisKonstantinos-Panagiotis Bouzoukis
Konstantinos-Panagiotis Bouzoukis
Georgios MoraitisGeorgios Moraitis
Georgios Moraitis
Vassilis KostopoulosVassilis Kostopoulos
Vassilis Kostopoulos
Vaios LappasVaios Lappas
Vaios Lappas
The proliferation of CubeSats in Earth orbit has accelerated dramatically in recent years, with projections indicating continued growth in the coming decades. This review examines the evolution of CubeSat applications, from basic technology demonstrations to complex mission capabilities, including Earth observation, telecommunications, astronomical research, biological experimentation, and deep-space exploration. A notable shift has occurred over the past fifteen years, with CubeSats transitioning from standalone platforms to integrated nodes within larger constellations, particularly for Earth observation and telecommunications applications. We analyze the key enabling factors behind the CubeSat revolution, including decreased launch costs, miniaturized electronics, standardized components, and institutional support frameworks. Through the examination of significant past, current, and planned missions, this paper provides a comprehensive overview of CubeSat capabilities across diverse application domains. The review highlights how these miniaturized satellite platforms are democratizing access to space while enabling innovative scientific and commercial applications previously restricted to larger spacecraft.

18 February 2022 in Drones
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Journal Article
Open access
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Vaios LappasVaios Lappas
Vaios Lappas
GZGiorgos Zoumponos
Giorgos Zoumponos
Vassilis KostopoulosVassilis Kostopoulos
Vassilis Kostopoulos
HLHae In Lee
Hae In Lee
Hyo-Sang ShinHyo-Sang Shin
Hyo-Sang Shin
ATAndra Trifas
Andra Trifas
EuroDRONE is an Unmanned Traffic Management (UTM) demonstration project, funded by the EU’s SESAR organization, and its aim is to test and validate key UTM technologies for Europe’s ‘U-Space’ UTM program. The EuroDRONE UTM architecture comprises cloud software (DroNav) and hardware (transponder) to be installed on drones. The proposed EuroDRONE system is a Highly Automated Air Traffic Management System for small UAVs operating at low altitudes. It is a sophisticated, self-learning system based on software and hardware elements, operating in a distributed computing environment, offering multiple levels of redundancy, fail-safe algorithms for conflict prevention/resolution and assets management. EuroDRONE focuses its work on functionalities which involve the use of new communication links, the use of vehicle-to-infrastructure (V2I) and vehicle-to-vehicle (V2V) technology to communicate information between drones and operators for safe and effective UTM functionality. Practical demonstrations that took place in Patras/Messolonghi in 2019 are presented and show the benefits and shortcomings of near-term UTM implementation in Europe.

3 February 2024 in Aerospace
Verified
Journal Article
Open access
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GKGrigorios Kostopoulos
Grigorios Kostopoulos
Konstantinos StamoulisKonstantinos Stamoulis
Konstantinos Stamoulis
Vaios LappasVaios Lappas
Vaios Lappas
Stelios K. GeorgantzinosStelios K. Georgantzinos
Stelios K. Georgantzinos
This study explores the shape-morphing behavior of 4D-printed structures made from Polylactic Acid (PLA), a prominent bio-sourced shape-memory polymer. Focusing on the response of these structures to thermal stimuli, this research investigates how various printing parameters influence their morphing capabilities. The experimental approach integrates design and slicing, printing using fused deposition modeling (FDM), and a post-printing activation phase in a controlled laboratory environment. This process aims to replicate the external stimuli that induce shape morphing, highlighting the dynamic potential of 4D printing. Utilizing Taguchi’s Design of Experiments (DoE), this study examines the effects of printing speed, layer height, layer width, nozzle temperature, bed temperature, and activation temperature on the morphing behavior. The analysis includes precise measurements of deformation parameters, providing a comprehensive understanding of the morphing process. Regression models demonstrate strong correlations with observed data, suggesting their effectiveness in predicting responses based on control parameters. Additionally, finite element analysis (FEA) modeling successfully predicts the performance of these structures, validating its application as a design tool in 4D printing. This research contributes to the understanding of 4D printing dynamics and offers insights for optimizing printing processes to harness the full potential of shape-morphing materials. It sets a foundation for future research, particularly in exploring the relationship between printing parameters and the functional capabilities of 4D-printed structures.

11 May 2020 in Aerospace
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Journal Article
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AGAlexis Gaude
Alexis Gaude
Vaios LappasVaios Lappas
Vaios Lappas
Following a global trend towards miniaturization, the population of nano- and micro-satellite continues to increase. CubeSats are standardized small size satellites based on 10 × 10 × 10 cm cube modules (1U) and are becoming sophisticated platforms despite their very small size. This paper details the design and the structural analysis of a Control Moment Gyroscope (CMG) actuator for agile CubeSats with a physical size up to 12U, which require high torque actuators. CMGs have inherited torque amplification capabilities and the recent advances in motor miniaturization make them ideal candidates for small satellite missions with slew rate requirements. The system’s requirements are derived based on conceptual agility requirements for an agile (highly maneuverable) CubeSat which needs to achieve a 90° maneuver in 90 s. With specific cost, mass and volume requirements, the proposed CMG design is based on some of the smallest available off-the-shelf electric motors and uses a light aluminum casing design. The proposed design uses stepper motors for the gimbal mechanism as a low cost, compact and low power solution, contributing to an overall low mass of the full CMG cluster. Static and dynamic analyses were performed to assess the mechanical integrity of the system for launch loads. Apart from a necessary custom control electronic board, the complete mechanical assembly has been designed including electrical hardware. Analyses demonstrate that the overall stress levels acting on the system are manageable by the CMG design. Bolted joints are critical and should be studied independently as the chosen model created singularities around these areas. Each individual CMG of the designed pyramidal cluster is shown to weigh about 35 g. Using the proposed CMG design with a customized avionics board, the complete CMG system is shown to weigh 250 g and occupies slightly more than ½U volume for a CubeSat, indicating the feasibility of CMGs for agile CubeSats.

1 January 2024 in Drones and Autonomous Vehicles
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Journal Article
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DMDimitrios Meimetis
Dimitrios Meimetis
SPSofia Papaioannou
Sofia Papaioannou
PKParaskevi Katsoni
Paraskevi Katsoni
Vaios LappasVaios Lappas
Vaios Lappas
Sancang Publishing House is mainly engaged in the publication and distribution of Chinese international open source journals. The journals cover engineering technology, mathematics and physics, humanities and society, information science, economics and management, medicine and health, agriculture, global environment and other disciplines, with the help of Internet thinking and modern Information technology, based on the scientific research needs of domestic universities and research institutions, strives to promote the exchange and dissemination of knowledge in the Chinese academic community. It can be published in journals, published papers, and published quickly. Sancang Publishing welcomes scientific research scholars to join us, participate in manuscript review, co-run journals, submit manuscripts, and grow and grow together with Chinese journals. If you have any comments or suggestions on the journal, please contact service@sciepublish.com.

12 February 2022 in Aerospace
Verified
Journal Article
Open access
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CPCharalampos Papakonstantinou
Charalampos Papakonstantinou
Georgios MoraitisGeorgios Moraitis
Georgios Moraitis
Vaios LappasVaios Lappas
Vaios Lappas
Vassilis KostopoulosVassilis Kostopoulos
Vassilis Kostopoulos
In this paper, a low-cost, miniature spacecraft attitude control simulator is presented for testing miniature actuators such as Nano Control Moment Gyroscopes (CMGs) for simple maneuvers. The experimental setup is composed by an attitude control system (ACS) that mainly consists of a four-CMG cluster in a pyramid configuration and a custom-made air bearing. The one-degree-of-freedom (DoF) air bearing is fabricated to reproduce the frictionless conditions of a nano-satellite in orbit. The ACS is made exclusively using low-cost commercial-off-the-shelf (COTS) components, whilst the air bearing is made using 3D-printed parts. Both hardware and software implementations are described in detail and the performance of the developed simulator is evaluated by two maneuver experiments. Despite the manufacturing imperfections, the ACS is capable of providing higher angular velocities than previously presented in the literature while following the theoretical or simulation data. The results indicate that it is possible to manufacture a low-cost, miniature actuator such as a CMG, using COTS components to demonstrate the operation of an agile nano-satellite. Any deviations from the theoretical values are addressed and several improvements are discussed to further enhance the performance of the air bearing testing platform.