Mission Impossible to Possible

Evaluation of aeroacoustic optimisation strategies for a generic flight mission of a tilt-propeller aircraft

Usual suspects meet mission impossible: Nutrient losses and effects of mitigation measures on a coastal catchment in the Baltic Sea region

Publisher Correction: Feasibility Analysis of a CubeSat Mission for Space Rider Observation and Docking

#PathArt: from glass slide to canvas; with a mission of enlightening the burdens of life

Fast recovery mode for micro-meteoroid impacts: A LISA mission study

Development of a micro-thrust measurement system and ground thrust measurement of the micro Hall thruster for Taiji mission

Mission analysis for the Radiation Environment Monitor for Energetic Cosmic rays (REMEC) mission

Toward Optimisation of a Sub-Terahertz Spaceborne VLBI Mission

Very Long Baseline Interferometry (VLBI) provides the finest angularresolution of all astronomical observation techniques. However, observationswith Earth-based instruments are approaching fundamental limits on angularresolution. These can only be overcome by placing at least one interferometricelement in space. In this paper, several concepts of spaceborne VLBI systemsare discussed, including TeraHertz Exploration and Zooming-in for Astrophysics(THEZA) and the Black Hole Explorer (BHEX). Spaceborne VLBI telescopes havesome of the most demanding requirements of any space science mission. The VLBIsystem as a whole includes globally distributed elements, each with their ownfunctional constraints, limiting when observations can be performed. Thisnecessitates optimisation of the system parameters in order to maximise thescientific return of the mission. Presented is an investigation into how theimpact of the functional constraints of a spaceborne VLBI telescope affect theoverall system performance. A preliminary analysis of how these constraints canbe minimised through optimisation of the spacecraft configuration and operationis also provided. A space-based VLBI simulation tool (spacevlbi) has beendeveloped to model such missions and its capabilities are demonstratedthroughout the paper. It is imperative that the functional constraints areconsidered early in the design of the future space-based VLBI systems in orderto generate feasible mission concepts and to identify the key technologydevelopments required to mitigate these limitations.

Autonomous optical navigation for DESTINY+: Enhancing misalignment robustness in flyby observations with a rotating telescope

DESTINY+ is an upcoming JAXA Epsilon medium-class mission to flyby multipleasteroids including Phaethon. As an asteroid flyby observation instrument, atelescope mechanically capable of single-axis rotation, named TCAP, is mountedon the spacecraft to track and observe the target asteroids during flyby. As inpast flyby missions utilizing rotating telescopes, TCAP is also used as anavigation camera for autonomous optical navigation during the closest-approachphase. To mitigate the degradation of the navigation accuracy, past missionsperformed calibration of the navigation camera's alignment before startingoptical navigation. However, such calibration requires significant operationaltime to complete and imposes constraints on the operation sequence. From theabove background, the DESTINY+ team has studied the possibility of reducingoperational costs by allowing TCAP alignment errors to remain. This paperdescribes an autonomous optical navigation algorithm robust to the misalignmentof rotating telescopes, proposed in this context. In the proposed method, themisalignment of the telescope is estimated simultaneously with the spacecraft'sorbit relative to the flyby target. To deal with the nonlinearity between themisalignment and the observation value, the proposed method utilizes theunscented Kalman filter, instead of the extended Kalman filter widely used inpast studies. The proposed method was evaluated with numerical simulations on aPC and with hardware-in-the-loop simulation, taking the Phaethon flyby in theDESTINY+ mission as an example. The validation results suggest that theproposed method can mitigate the misalignment-induced degradation of theoptical navigation accuracy with reasonable computational costs suited foronboard computers.