Jouni Polkko
A5065646406- Planetary Science and Exploration
- Astro and Planetary Science
- Space Exploration and Technology
- Spacecraft and Cryogenic Technologies
- Spaceflight effects on biology
- Spacecraft Design and Technology
- Space Science and Extraterrestrial Life
- Space Satellite Systems and Control
- Aerospace Engineering and Energy Systems
- Spacecraft Dynamics and Control
- Gas Dynamics and Kinetic Theory
- Inertial Sensor and Navigation
- Solar and Space Plasma Dynamics
- Atmospheric and Environmental Gas Dynamics
- Scientific Research and Discoveries
- Ionosphere and magnetosphere dynamics
- Aeolian processes and effects
- Air Quality Monitoring and Forecasting
- Sensor Technology and Measurement Systems
- Methane Hydrates and Related Phenomena
- Advanced MEMS and NEMS Technologies
- Meteorological Phenomena and Simulations
- Astronomical Observations and Instrumentation
- Offshore Engineering and Technologies
- Geophysics and Gravity Measurements
Finnish Meteorological Institute
2013-2024
Johns Hopkins University Applied Physics Laboratory
2022
Carnegie Institution for Science
2022
University of the Basque Country
2022
Johns Hopkins University
2022
Tartu Observatory
2015
Finnish Geospatial Research Institute
1998
The electric solar wind sail (E-sail) is a space propulsion concept that uses the natural dynamic pressure for producing spacecraft thrust. In its baseline form, E-sail consists of number long, thin, conducting, and centrifugally stretched tethers, which are kept in high positive potential by an onboard electron gun. gains efficiency from fact effective area, i.e., structure can be millions times larger than physical area thin tethers wires, offsets very weak. Indeed, according to most...
The Phoenix Mars Lander detected a larger number of short (∼20 s) pressure drops that probably indicate the passage convective vortices or dust devils. Near‐continuous measurements have allowed for monitoring frequency these events, and data from other instruments orbiting spacecraft give information on how events relate to seasons weather phenomena at landing site. Here 502 were identified with drop than 0.3 Pa occurring in 151 sol mission (L s 76 148). diurnal distributions show peak...
In the first 100 Martian solar days (sols) of Mars Science Laboratory mission, Rover Environmental Monitoring Station (REMS) measured seasonally evolving diurnal cycles ultraviolet radiation, atmospheric pressure, air temperature, ground relative humidity, and wind within Gale Crater on Mars.As an introduction to several REMS-based articles in this issue, we provide overview design performance REMS sensors discuss our approach mitigating some difficulties encountered following landing,...
REMS‐P, the pressure measurement subsystem of Mars Science Laboratory (MSL) Rover Environmental Measurement Station (REMS), is performing accurate observations Martian atmospheric surface pressure. It has demonstrated high data quality and good temporal coverage, carrying out first in situ equatorial regions. We describe REMS‐P initial results by MSL mission sol 100 including instrument performance illustrate some interpretations observed features. The show both expected new phenomena at...
Abstract NASA’s Perseverance rover’s Mars Environmental Dynamics Analyzer is collecting data at Jezero crater, characterizing the physical processes in lowest layer of Martian atmosphere. Here we present measurements from instrument’s first 250 sols operation, revealing a spatially and temporally variable meteorology Jezero. We find that temperature four heights capture response atmospheric surface to multiple phenomena. observe transition stable night-time thermal inversion daytime, highly...
Abstract The Mars Environmental Dynamics Analyzer (MEDA) on board Perseverance includes first‐of‐its‐kind sensors measuring the incident and reflected solar flux, downwelling atmospheric IR upwelling flux emitted by surface. We use these measurements for first 350 sols of 2020 mission (L s ∼ 6°–174° in Martian Year 36) to determine surface radiative budget calculate broadband albedo (0.3–3 μm) as a function illumination viewing geometry. Together with MEDA ground temperature, we thermal...
The Mars Science Laboratory (MSL) made a successful landing at Gale crater early August 2012. MSL has an environmental instrument package called the Rover Environmental Monitoring Station (REMS) as part of its scientific payload. REMS comprises instrumentation for observation atmospheric pressure, temperature air, ground temperature, wind speed and direction, relative humidity (REMS-H), UV measurements. We concentrate on describing REMS-H measurement performance initial observations during...
Abstract The pressure sensors on Mars rover Perseverance measure the field in Jezero crater regular hourly basis starting sol 15 after landing. present study extends up to 460 encompassing range of solar longitudes from L s ∼ 13°–241° (Martian Year (MY) 36). data show changing daily cycle, sol‐to‐sol seasonal evolution mean driven by CO 2 sublimation and deposition cycle at poles, characterization six components atmospheric tides their relationship dust content atmosphere. They also presence...
Abstract We characterize vortex and dust devils (DDs) at Jezero from pressure winds obtained with the Mars Environmental Dynamics Analyzer (MEDA) instrument on 2020 over 415 Martian days (sols) ( Ls = 6°–213°). Vortices are abundant (4.9 per sol drops >0.5 Pa correcting gaps in coverage) they peak noon. At least one every five vortices carries dust, 75% of all Δ p > 2.0 dusty. Seasonal variability was small but DDs were during a storm 152°–156°). more frequent intense terrains lower...
Abstract The Mars 2020 mission rover “Perseverance”, launched on 30 July by NASA, landed successfully 18 February 2021 at Jezero Crater, (Lon. E 77.4509° Lat. N 18.4446°). landing took place solar longitude Ls = 5.2°, close to start of the northern spring. Perseverance's payload includes relative humidity sensor MEDA HS (Mars Environmental Dynamics Analyzer Humidity Sensor), which operations, performance, and first observations from sol 80 410 (Ls 44°–210°) operations we describe. measured...
Abstract The Mars2020 Perseverance Rover landed successfully on the Martian surface Jezero Crater floor (18.44°N, 77.45°E) at solar longitude, L s , ∼5° in February 2021. Since then, it has produced highly valuable environmental measurements with a versatile scientific payload including MEDA (Mars Environmental Dynamics Analyzer) suite of sensors. One systems is PS pressure sensor system, which weighs 40 g and an estimated absolute accuracy better than 3.5 Pa resolution 0.13 Pa. We present...
In this article, we report on the in-orbit experience - an overview of ESTCube-1 operations from launch until experiment, as well lessons learned five years development and almost two operations. Lessons are identified point view system engineering, electrical mechanical software testing measurements, payload, management. Detailed flight results will be provided in dedicated articles. We hope that other teams can benefit our experience.
Abstract The Mars Environmental Dynamics Analyzer, onboard the Perseverance rover, is a meteorological station that operating on and includes, among other sensors, radiometer Radiation Dust Sensor (RDS). From RDS irradiance observations, total of 374 dust devils (DDs) were detected for first 365 sols mission (Ls = 6°–182°), which along with wind pressure measurements, we estimated DD frequency formation at Jezero between 1.3 3.4 km −2 sol −1 (increasing as move from spring into summer). This...
Abstract The Mars Sample Return mission intends to retrieve a sealed collection of rocks, regolith, and atmosphere sampled from Jezero Crater, Mars, by the NASA Perseverance rover mission. For all life-related research, it is necessary evaluate water availability in samples on Mars. Within first Martian year, has acquired an estimated total mass 355 g rocks 38 μmoles atmospheric gas. Using in-situ observations rover, we show that present-day environmental conditions at allow for hydration...
The concept of Plasma Brake is based on the ionospheric plasma Coulomb drag. It analogous to air drag in neutral atmosphere. dragging obstacle against orbital RAM flow established by an electrostatic field with a high voltage difference respect ambient plasma, typically -1 kV. potential structure supported long 4-wire tether single aluminium wires thickness less than 50 um. redundant makes resilient micro-meteoroids. deployed stabilised gravity gradient. As negative attracting ions, current...
NASA's upcoming Dragonfly rotorcraft mission is planned to be deployed the surface of Saturn’s moon Titan [1]. As part Entry Aerosciences Measurements (DrEAM) suite [2], entry capsule will include a subsystem known as COmbined Sensor System for Atmosphere (COSSTA). This being developed by Supersonic and Hypersonic Technologies Department at DLR Institute Aerodynamics Flow Technology, in collaboration with NASA. One components COSSTA pressure sensor Finnish Meteorological (FMI)....
In situ surface pressures measured at 2 s intervals during the 150 sol Phoenix mission are presented and seasonal variations discussed. The lightweight Barocap®/Thermocap® pressure sensor system performed moderately well. However, original data processing routine had problems because thermal environment of was subject to more rapid than been expected. Hence, updated after landed. Further evaluation development a correction needed since temperature dependences Barocap heads have drifted...
Dragliner [1, 2] is an ESA funded study to define the requirements and a preliminary design of passive Coulomb Drag based deorbit system capable bringing down LEO spacecrafts in order magnitude shorter time than current regulations for re-entry spacecraft (25 years), while using significantly less resources compared traditional deorbiting methods like chemical or electric propulsion. Other main are low mass independence from resources. The led by Finnish Meteorological Institute, other...