Climate change is a critical challenge for the nation and human society. Changes in Earth’s climate are affected not only by anthropogenic forcing but also by external, natural factors. APL is developing space-based technologies that will enable new measurements of the delicate Earth energy balance that affect how our climate responds in the future. One such instrument is the Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) project, and it is miniaturized to fit on a Cubesat. APL scientists also use Earth system models and satellite observations to better understand how anthropogenic and natural factors impact decadal-scale variations in middle atmospheric temperature and composition.
APL conducts laboratory and airborne experiments to measure vegetation fluorescence, which is a key measurement of the efficiency of photosynthesis and vegetation health. Remote monitoring of vegetation from space is of interest for precision farming, forest management, and assessment of the terrestrial carbon budget and the transfers between carbon pools. Solar-induced chlorophyll fluorescence (ChlF), linked closely to photosynthetic efficiency, can be used to monitor the plant health and to assess the terrestrial carbon budget. APL built the Airborne Plant Fluorescence Sensor (APFS), a high spectral resolution Fabry-Perot interferometer optimized specifically for the detection of weak ChlF radiance, to measure the terrestrial carbon budget.
Ocean remote sensing research is conducted for both civilian and military applications in the marine environment. APL efforts include hurricane tracking, extraction of oceanographic information from synthetic aperture radar (SAR) imagery, radar altimetry, monitoring of Arctic and Antarctic glacial and sea ice, and hyperspectral imaging for ocean color and biogeoscience. APL researchers deployed a delay-Doppler radar ice sounder to measure glacial ice thicknesses in Greenland and Antarctica (Petermann Glacier example) for the NASA ESTO Instrument Incubator program. APL operationally monitors ocean winds using SAR satellites, including RADARSAT-2 (Sakhalin Island example) and Sentinel-1A (Cape Cod example) for NOAA and the National Ice Center. A future extension will include an algorithm for joint active/passive identifications of sea ice types and concentrations (example from submission to Remote Sensing). New instrumentation, such as a hyperspectral sensor, would image coastal ocean color from space.
JHUAPL conducts ground-breaking research for NASA, NOAA, and the U.S. Air Force in several disciplines of Earth Science including cloud remote sensing, aerosol detection and characterization, 3D wind retrieval, and line-of-sight characterization. APL carries out this work with a variety of atmospheric modeling tools and space-based remote sensing such as GOES imagery. Atmospheric instrumentation at APL is designed to be compact and lightweight to enable a variety of collection platforms ranging from aircraft to large satellites. JHUAPL collected imagery for airborne tests of the Multi-Spectral Imaging System in 2013. Several of the instruments on MSIS have been upgraded and adapted for flight to support NASA Earth Science research. Current efforts of APL can be categorized into three broad areas: cloud characterization including cloud geometric heights (CGH) calculated geometrically with stereo-photometric methods, cloud-top temperatures (CTTs), and cloud motion vectors (CMVs). These quantities are used for atmospheric research including severe wind events, hurricane forecasting, ocean-atmosphere interactions and cloud forcing of the Earth's climate.
The heliospheric section investigates the acceleration, propagation, and transport of solar wind, suprathermal, and energetic particles (solar to cosmic) in the heliosphere from the Sun and beyond. We are constantly advancing our understandings of particle acceleration and transport in the heliosphere and apply our knowledge to other part of the Universe. We use advance physics based particle stimulation tools and analyze data from instruments on both NASA and ESA missions, most of those we built and operate like ACE, Wind, Stereo, and Voyager. We are also building the next generation of particle instrumentations for future missions such as Solar Probe Plus and Solar Orbiter. Both of these will explore the Solar atmosphere and inner heliosphere that have never been explored before.
Certain regions of our upper atmosphere are prone to solar influence and merge into Earth Science research. The Mesosphere and Lower Thermosphere/Ionosphere (MLTI) region is a gateway between Earth's environment and space, where the Sun's energy is first deposited into Earth's environment. The APL built TIMED mission has extensively studied the MLTI region located approximately 40-110 miles (60-180 kilometers) above the surface. For over 15 years, TIMED has measured the impact of solar- and human-induced disturbances on Earth’s upper atmosphere by investigating the energy transfer into and out of the MLTI region (energetics), as well as the basic structure (i.e., pressure, temperature, and winds) that results from the energy transfer into the region (dynamics). Visible manifestations of space weather in the upper atmosphere, Aurora, occur primarily in the thermosphere. Aurora manifest as stunning colors and effects in the night sky, particularly at northern latitudes.
The Magnetosphere-Ionosphere (M-I) coupling is the final step in the transport of electrodynamic energy from Sun to Earth. APL has significant investigations into the M-I system with global specifications of field-aligned currents (Birkeland currents), ionospheric currents and convection, as well as with local measurements made by various space-borne and ground-based instruments. Our goal is to understand the global dynamics of the M-I system as well as fundamental physical processes such as auroral acceleration, precipitation, and wave excitation. By integrating different data sets and synthesizing new insights about individual processes, we can characterize how the M-I system responds to external conditions and generates space weather. This research of the terrestrial M-I system improves our understanding not only of the dynamics of Earth’s upper atmosphere, but also the M-I systems of different planets. APL’s current operational M-I projects includes AMPERE, SuperMAG, SuperDARN, and DMSP.
Earth’s magnetosphere captures and processes energy from the interplanetary environment, or solar wind, and delivers some of it to the ionosphere and upper atmosphere. The near-Earth space acts as a giant particle accelerator and produces high-energy particle radiation belts. We investigate the processes that govern the energy transfer from the solar wind into the magnetosphere, transport and accelerate energetic particles, and control the coupling with the ionosphere-atmosphere. APL scientists build energetic particle and energetic neutral atom camera instruments for magnetospheric missions, analyze particle and magnetic field data from multiple missions, and then combine those data sets with state-of-the-art magnetohydrodyanmic (MHD) and kinetic models to investigate and resolve the fundamental processes responsible for regulating the transport and excitation.
APL has a long history of providing instruments to study the particle phenomena at the outer planets. Our robust experimental program has covered the outer solar system with charged particle or neutral atom instruments: Jupiter (Juno/JEDI, New Horizons/PEPSSI, Cassini/MIMI, Galileo/EPD, and Voyager/LECP), Saturn (MIMI), Uranus (LECP), Neptune (LECP), and Pluto (PEPSSI). The New Horizons encounter with the Kuiper Belt Object known as 2014 MU69 is planned for January 1, 2019. APL-built and operated New Horizons spacecraft and it performed an intial reconnaissance of Pluto on July 14, 2015. We also are building innovative instruments for NASA’s Europa Mission (PIMS) and the European Space Agency’s JUICE mission to Jupiter (JENI and JOEE). APL instruments measure ions, electrons, and neutral atoms that arise from or interact with the plasmas, fields, dust, and neutral gases controlled by planetary magnetospheres and atmospheres.
Solar Physics explores solar activity through novel instrument development, advanced modeling, and innovative data analysis methods. APL scientists conduct investigations in almost every area of solar physics, from high-resolution magnetic field measurements to spectroscopy of the upper atmosphere to the physics of coronal mass ejections on the Sun and other phenomenon such as jet, plumes, solar energetic particles, comets. Our focus is on understanding the drivers of Space Weather and on translating research results to actionable operational products. Our skills in instrument development, systems engineering, project management, and advanced image processing techniques and data analytics inform our science leadership on missions such as STEREO, Solar Probe Plus, and Solar Orbiter.
In our economy, commerce is highly dependent on global information systems. Yet the space infrastructure that supports $200 billion per year of economic activity is susceptible to disruption from space weather with little to no warning; and there is no active system in place to forecast these potentially disruptive events. APL is working with key stakeholders to provide a coordinated program to transition from fundamental research to operationalize the predictive capability to mitigate and utilize the effects of severe space weather events in civil and military venues. Scientists at APL have developed a variety of space weather products, many of which have been transitioned to various agencies that include the Air Force and NOAA.
Heliophysics theory and modeling conducts fundamental research with the overarching goal to not only reveal, understand, and characterize the physical processes underlying the observed behavior of the Heliosphere, but also to build assets and knowledge for Space Weather forecasting. The Heliosphere is a system of interconnected plasma environments that can only be understood in concert, rather than in isolation. Studies range from the inner heliosphere to the ionosphere and include the solar wind, global magnetosphere, magnetosphere-ionosphere coupling, radiation belts and ring current. APL theory and modeling expertise ranges from kinetic plasma theory to magnetohydrodynamic simulations, single particle motion, wave-particle interactions, data mining, empirical modeling and numerical algorithm development, including massively parallel applications.
Asteroids are small rocky bodies orbiting the sun; they are remnants from the formation of the inner planets. NASA’s first asteroid reconnaissance mission, NEAR Shoemaker, was built by APL and became the first mission to carry out a landing on a small body in 2001. APL participates in recent and ongoing missions such as NASA’s OSIRIS-REx and Japan’s Hayabusa and Hayabusa-2 sample return missions, and NASA’s Dawn mission to Ceres and Vesta, and is active in meteorite petrologic and geochemical research. Future mission opportunities include the Double Asteroid Redirection Test (DART). For DART, APL will build a spacecraft to demonstrate a kinetic impactor for planetary defense. Beyond mission work, we collect and study asteroid data by using telescopes on the Earth, in balloons, and on air- and space-borne observatories.
The Kuiper Belt is a vast reservoir of small bodies that orbit the Sun near the plane of the solar system beyond the orbit of Neptune. Kuiper Belt objects, or “KBOs” for short, have icy compositions and surfaces coated by solid methane, nitrogen, and carbon dioxide as well as water ice. Some KBOs become perturbed by the outer planets’ gravity into orbits that bring them into the inner solar system. When KBO’s approach the Sun, their icy surfaces warm and their ices sublime, forming tails and thin atmospheres called “comae,” at which point KBOs become known as comets. APL scientists study comets from groundbased and space-based telescopes including the Hubble Space Telescope, and have participated in missions to comets and KBOs including Deep Impact, New Horizons, and Rosetta.
Pluto and Ceres are the best known dwarf planets – bodies that are round and orbit the Sun like the planets, but have not cleared other objects in their neighborhood. Dwarf planets occur either in the asteroid belt, like Ceres, or in the Kuiper Belt, home to Pluto. APL built and managed the first spacecraft to explore Pluto, New Horizons, and in 2015 revealed a complex world with extensive icy plains and heterogeneous surface compositions. APL scientists also participated in the Dawn mission, the first in-depth geologic studies of the dwarf planet Ceres to understand the evolution of its rocky surface features.
The inner planets of our solar system are extensively studied by APL scientists and science missions. APL developed and built the MESSENGER mission to orbit Mercury and completed four years of orbital measurements. Our expertise is at work on several instruments onboard the Lunar Reconnaissance Orbiter (LRO) including the LROC camera, the Mini-RF imaging radar, the Diviner thermal infrared radiometer, and the Lyman Alpha Mapping Project (LAMP), and LRO returns unprecedented views of the Moon. At Mars, APL’s CRISM hyperspectral imager on the Mars Reconnaissance Orbiter (MRO) has mapped most of Mars and taken tens of thousands of high-resolution images of selected areas. APL’s other Mars investigations include MRO’s HiRISE imaging investigation, the Mars Exploration Rover Opportunity, and the Mars Science Laboratory Curiosity. A NASA’s Solar System Exploration Research Institute team, VORTICES, based at APL focuses on volatiles in the inner solar system and on small bodies.
Lunar expertise at APL ranges among spectroscopy from the far-ultraviolet to the thermal infrared to study composition and space weathering, geology from the history of volcanism, to the impact cratering process, to regolith evolution, and the study of volatiles, both native to the Moon, and those that migrate through the Moon’s exosphere and are cold-trapped at the poles. Our scientists lead several instruments on the Lunar Reconnaissance Orbiter (LRO), including the LROC cameras that image the Moon unprecedented resolution, the Mini-RF imaging radar which provides critical information about surface properties and the search for volatiles, the Diviner thermal infrared radiometer which reveals surface temperature and rock abundance, and the Lyman Alpha Mapping Project (LAMP) that uses reflected starlight to image permanently shadowed regions at the poles.
The gas giants Jupiter and Saturn and the ice giants Uranus and Neptune are the four outer planets of our solar system. Dozens of orbiting moons – ranging in size from small, irregularly shaped bodies to Titan and Ganymede, both larger than Mercury – make each of the outer planets a miniature solar system unto itself. JHU/APL scientists have been involved in several missions to the outer planets. Voyagers 1 and 2, carrying the JHU/APL-built Low Energy Charged Particle (LECP) experiments, performed an outer planets grand tour. Galileo carried the JHU/APL-built Energetic Particle Detector to orbit Jupiter and survey its moons. Cassini, the first Saturn orbiter, carried JHU/APL's Magnetospheric Imaging Instrument. JHU/APL's New Horizons zipped by Jupiter on its ways to Pluto and captured images of the planet and several of its large moons. Juno arrived in orbit about Jupiter in 2016, carrying with it JHU/APL’s Jupiter Energetic particle Detector Instrument (JEDI). JHU/APL is partnered with JPL in developing NASA’s Europa Mission, and is building part or all of three instruments: the Europa Imaging System (EIS), Plasma Instrument for Magnetic Sounding (PIMS), and Mapping Imaging Spectrometer for Europa (MISE). JHU/APL scientists are also helping to plan future exploration of the ice giants.