NASA Science Missions Research Articles

Updates on CYGNSS Ocean Surface Wind Validation in the Tropics

Abstract Global Navigation Satellite System Reflectometry (GNSS-R)-based wind retrieval techniques use the global positioning system (GPS) signals scattered from the ocean surface in the forward direction, and can potentially work in all weather conditions. An overview of recent progress made in the Cyclone Global Navigation Satellite System (CYGNSS) level-2 surface wind products is given. To this end, four publicly released CYGNSS surface wind products—Science Data Record (SDR) v2.1, SDR v3.0, Climate Data Record (CDR) v1.1, and science wind speed product NOAA v1.1—are validated quantitatively against high-quality data from tropical buoy arrays. The latest released CYGNSS wind products (e.g., CDR v1.1, SDR v3.0, NOAA v1.1), as compared with these tropical buoy data, significantly outperform the SDR v2.1. Moreover, the uncertainty among these products is found to be less than 2 m s−1 root-mean-squared difference, meeting the NASA science mission level-1 uncertainty requirement for wind speeds below 20 m s−1. The quality of the CYGNSS wind is further assessed under different precipitation conditions in low winds, and in large-scale convective regions. Results show that the presence of rain appears to cause a slightly positive wind speed bias in all CYGNSS data. Nonetheless, the outcomes are encouraging for the recently released CYGNSS wind products in general, and for CYGNSS data in regions with precipitating deep convection. The overall comparison indicates a significant improvement in wind speed quality and sample size when going from the older version to any of the newer datasets.

NASA'S NEURODIVERSITY NETWORK (N3)

NASA's Neurodiversity Network (N3) is a five-year program that has been funded as part of NASA's Science Activation Network. N3's main goal is to provide a pathway to NASA participation and STEM employment for neurodiverse learners, with a focus on those on the autism spectrum. Through the N3 program, we are enabling STEM education for a segment of the population that is significantly underserved through a process in which existing NASA education resources are redesigned with significant input from autistic learners and their instructors. The co-design process occurs primarily in informal environments, including high school summer programs, and camps and activity sessions for middle school students sponsored by the New York Hall of Science. N3 also offers a mentored summer internship program for at least ten neurodiverse high school students each year. Mentoring is provided by NASA Subject Matter Experts, individuals who collectively possess expertise that spans NASA's Science Mission Directorate.

It Is So Nice to See You: ACE Is Back!

“More than 20 years ago, the Webb team set out to build the most powerful telescope that anyone has ever put in space. . . . Today we can say that design is going to deliver.” —Thomas Zurbuchen, associate administrator for NASA's Science Mission I readily admit, the time since ACE19 has been trying. The decisions to cancel ACE20 and ACE21 were hard to make. The tipping point in each case was AWWA's commitment to protecting public health—a commitment that extends beyond the delivery of safe drinking water to include safety at AWWA events for members and water colleagues around the world. As we know all too well, there was no possible way to hold ACE safely in 2020 and 2021. All of which makes this year that much more special. So, what do we have in store for ACE22? To start with, we will open the conference with a talk that is nothing short of out of this world. The opening-session keynote speaker is Thomas Zurbuchen, NASA's associate administrator for the Science Mission Directorate. My hope is he will talk about his work finding water on Mars and what it means for us here on Earth. Also, I suspect he will speak to the importance of the James Webb Space Telescope—the world's largest and most powerful space science telescope, which has the ability to view distant worlds around other stars. Speaking of looking forward, AWWA will officially launch its Water 2050 program at ACE22. This program will focus on water in the mid-century and the drivers that will take us there. The idea behind Water 2050 is that, by understanding these drivers—sustainability, technology, economics, governance, and social and demographic factors—water professionals can take steps to create our desired water future. As is the case for many things, Water 2050 (like NASA's Webb telescope) requires starting the work well in advance of needing the results. The reality is that in water years, 2050 is not that far away, so starting now is critical. At ACE22, the easiest way to learn more about AWWA's Water 2050 is to visit the AWWA pavilion on the exhibit floor. If you are an emerging professional (or the mentor for one), look for announcements at ACE about AWWA's Transformative Leaders Academy. This yearlong program is a mix of virtual and face-to-face events. It focuses on the leadership skills needed by the next generation of water leaders—those who will take us to 2050. We are fortunate to have partnered with WaterNow Alliance on this program and to have received a grant that allows us to waive the tuition for this inaugural year. The technical programs will be chock-full of the information you need, including the latest on the Infrastructure Investment and Jobs Act of 2021, the newest thinking from the US Environmental Protection Agency, and approaches to addressing cybersecurity. Check out the full ACE program on the AWWA Events app. As you would expect, the exhibit floor will be a great place to reconnect with business partners. The exhibitors are ready to greet you and provide updates. Many events like the Tapping Contest, Hydrant Hysteria, and Best of the Best water taste test will also be on the exhibit floor. And stop by the Innovation Hub, powered by Isle Utilities, to learn about emerging technologies and innovation. Wednesday evening, everyone can gather at the Wrap Party to celebrate the tradition of passing the gavel. This year's gavel-passing will not only symbolize a change in leadership but also how the water community is emerging stronger after facing three years of previously unknown challenges. Finally, I have a feeling that many ACE events will begin with someone saying, “It is so nice to see all of you!” I chuckle every time I hear that phrase, yet I know that people say it because it is true. Over the past three years, we have missed being together and now, as with other COVID-related limitations, that too can come to an end. See you at ACE22!

Advancing Space Science Requires NASA Support for Coordination Between the Science Mission Directorate Communities

We outline specific steps that NASA and the space science community can take to advance collaboration and coordination between the communities represented by the four NASA Science Mission Directorate Divisions. It is important to note that the only way that this effort can succeed is if NASA initiates and supports it through directed resources.

CYGNSS Ocean Surface Wind Validation in the Tropics

AbstractSurface wind plays a crucial role in many local/regional weather and climate processes, especially through the exchanges of energy, mass, and momentum across Earth’s surface. However, there is a lack of consistent observations with continuous coverage over the global tropical ocean. To fill this gap, the NASA Cyclone Global Navigation Satellite System (CYGNSS) mission was launched in December 2016, consisting of a constellation of eight small spacecrafts that remotely sense near-surface wind speed over the tropical and subtropical oceans with relatively high sampling rates both temporally and spatially. This current study uses data obtained from the Tropical Moored Buoy Arrays to quantitatively characterize and validate the CYGNSS derived winds over the tropical Indian, Pacific, and Atlantic Oceans. The validation results show that the uncertainty in CYGNSS wind speed, as compared with these tropical buoy data, is less than 2 m s−1 root-mean-square difference, meeting the NASA science mission level-1 uncertainty requirement for wind speeds below 20 m s−1. The quality of the CYGNSS wind is further assessed under different precipitation conditions, and in convective cold-pool events, identified using buoy rain and temperature data. Results show that CYGNSS winds compare fairly well with buoy observations in the presence of rain, though at low wind speeds the presence of rain appears to cause a slight positive wind speed bias in the CYGNSS data. The comparison indicates the potential utility of the CYGNSS surface wind product, which in turn may help to unravel the complexities of air–sea interaction in regions that are relatively undersampled by other observing platforms.

Blind validation study of parametric cost estimation tool SEER-H for NASA space missions

One of the primary parametric cost modeling tools used by NASA and the aerospace industry to estimate the development and production cost of future spacecraft hardware is SEER-H by Galorath. To date, no independent validation of this tool for cost estimation of space missions has been reported in the literature. In the present validation study, cost estimators used SEER-H to estimate the cost of twelve different past NASA science missions. The estimators were prevented from knowing the actual cost of the missions in an effort to minimize cognitive biases. The point estimates of SEER-H had an average error of 23%, median error of −0.3%, and a standard deviation of 43%. Nine of the twelve mission's actual costs fell within the 80% confidence interval of SEER's probabilistic estimates. Several factors independent of SEER that may have affected the accuracy of the results have been identified and are discussed; these include: uncertainty in the technical data used for the estimates, the methods used to estimate uncertainty in spacecraft component mass and numbers of prototypes, and the experience of the estimators.

The CubeSat Mission to Study Solar Particles

The CubeSat Mission for studying Solar Particles is a NASA Science Mission Directorate and Heliophysics Division funded 6U Interplanetary CubeSat Science Mission. CuSP is scheduled to launch in mid-2020 as a secondary payload on the SLS EM -1 (Exploratory Mission One) flight. CuSP is a pathfinder mission for Space Weather Research as it will be the first heliophysics science mission to be placed in heliocentric orbit outside the influence of the Earth's magnetosphere. CuSP features three complementary, miniaturized sensors to address two science objectives: study the sources and acceleration mechanisms of solar and IP particles in near-Earth orbit, and support space weather research by determining proton radiation levels during SEP events and identifying properties of ST ions that could help predict the arrival of strong CME-driven IP shock waves that produce geomagnetic storms.

Qualitative Assessment of Aerocapture and Applications to Future Missions

We examine the current state of readiness of aerocapture at several destinations of interest, to identify what technologies are needed and to determine if a technology demonstration mission is required, before the first use of aerocapture for a science mission. The study team concluded that the current state of readiness is destination dependent, with aerocaptured missions feasible at Venus, Mars, and Titan with current technologies. The use of aerocapture for orbit insertion at the ice giant planets Uranus and Neptune requires at least additional study to assess the expected performance of new guidance, navigation, and control algorithms and possible development of new hardware, such as a mid-lift-to-drag entry vehicle shape or new thermal protection system materials. A variety of near-term activities could contribute to risk reduction for missions proposing the use of aerocapture, but an end-to-end, system-level technology demonstration mission is not deemed necessary before the use of aerocapture for a NASA science mission.

The Integrated Product Team Educational Experience

The Integrated Product Team (IPT) is a multidisciplinary and multi-university STEM educational project whose goal is to provide the opportunity for undergraduate scientists and engineers to translate stakeholder needs and requirements into viable science and engineering design solutions via a distributed multidisciplinary team environment in a Pre-Phase A design activity. The core of the project is a two-semester senior design sequence where science, engineering, and liberal arts undergraduate students form multidisciplinary competitive teams to develop system concepts of interest for NASA Science Mission Directorate. The two-semester design sequence for the IPT project emphasizes four key principles that are critical for any new scientist/engineer in the competitive environment of today: systems thinking, communication, teamwork, and design. These four principles are taught over four phases in the two-semester sequence: requirements development, team formation and mission architecture development, system definition and development, and system design. Replicating the real world of spacecraft design, the science team members determine the science requirements for the mission, develop the science traceability matrix, select the correct instrumentation to meet the science requirements, and develop the science operations plan. The engineering team members design and develop the spacecraft(s) necessary to accomplish the science requirements and provide computer-aided design models of each spacecraft.

The Instruments and Capabilities of the Miniature X-Ray Solar Spectrometer (MinXSS) CubeSats

The Miniature X-ray Solar Spectrometer (MinXSS) CubeSat is the first solar science oriented CubeSat mission flown for the NASA Science Mission Directorate, with the main objective of measuring the solar soft X-ray (SXR) flux and a science goal of determining its influence on Earth’s ionosphere and thermosphere. These observations can also be used to investigate solar quiescent, active region, and flare properties. The MinXSS X-ray instruments consist of a spectrometer, called X123, with a nominal 0.15 keV full-width at half-maximum (FWHM) resolution at 5.9 keV and a broadband X-ray photometer, called XP. Both instruments are designed to obtain measurements from 0.5 – 30 keV at a nominal time cadence of 10 s. A description of the MinXSS instruments, performance capabilities, and relation to the Geostationary Operational Environmental Satellite (GOES) 0.1 – 0.8 nm flux is given in this article. Early MinXSS results demonstrate the capability of measuring variations of the solar spectral soft X-ray (SXR) flux between 0.8 – 12 keV from at least GOES A5–M5 (5 times 10^{-8},mbox{--},5 times10^{-5}~mbox{W},mbox{m}^{-2}) levels and of inferring physical properties (temperature and emission measure) from the MinXSS data alone. Moreover, coronal elemental abundances can be inferred, specifically for Fe, Ca, Si, Mg, S, Ar, and Ni, when the count rate is sufficiently high at each elemental spectral feature. Additionally, temperature response curves and emission measure loci demonstrate the MinXSS sensitivity to plasma emission at different temperatures. MinXSS observations coupled with those from other solar observatories can help address some of the most compelling questions in solar coronal physics. Finally, simultaneous observations by MinXSS and the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) can provide the most spectrally complete soft X-ray solar flare photon flux measurements to date.

Current and Future Perspectives of Aerosol Research at NASA Goddard Space Flight Center

Aerosols are tiny atmospheric particles that are emitted from various natural and anthropogenic sources. They affect climate through direct and indirect interactions with solar and thermal radiation, clouds, and atmospheric circulation (Solomon et al. 2007). The launch of a variety of sophisticated satellite-based observing systems aboard the Terra, Aqua, Aura, SeaWiFS (see appendix for all acronym expansions), CALIPSO, and other satellites in the late 1990s to mid-2000s through the NASA EOS and other U.S. and non-U.S. programs ushered in a golden era in aerosol research. NASA has been a leader in providing global aerosol characterizations through observations from satellites, ground networks, and field campaigns, as well as from global and regional modeling. AeroCenter (http://aerocenter.gsfc.nasa.gov/), which was formed in 2002 to address the many facets of aerosol research in a collaborative manner, is an interdisciplinary union of researchers (~200 members) at NASA GSFC and other nearby institutions, including NOAA, several universities, and research laboratories. AeroCenter hosts a web-accessible regular seminar series and an annual meeting to present up-to-date aerosol research, including measurement techniques; remote sensing algorithms; modeling development; field campaigns; and aerosol interactions with radiation, clouds, precipitation, climate, biosphere, atmospheric chemistry, air quality, and human health. The 2013 annual meeting was held at the NASA GSFC Visitor Center on 31 May 2013, which coincided with the seventh anniversary of the passing of Yoram Kaufman, a modern pioneer in satellite-based aerosol science and the founder of AeroCenter. The central theme of this year's meeting was current and future perspectives of NASA's aerosol science and satellite missions.

Scientists Identify Exploration Goals for Venus

Since the turn of the millennium, a large proportion of NASA's planetary science missions—including spacecraft and payloads on four orbiting missions and three rovers—has targeted Mars in preparation for future human missions to the red planet. Less studied, however, is Venus.

Radiation belt probes launched

Storms on Earth delayed by only a few days the launch of NASA's Radiation Belt Storm Probes (RBSP), which blasted off on 30 August for a 2‐year tour to explore the Van Allen radiation belts. The two satellites will help scientists learn about the processes that affect electrons and ions in the donut‐shaped belts and how the belts change in the context of geomagnetic storms. “The information collected from these probes will benefit the public by allowing us to better protect our satellites and understand how space weather affects communications and technology on Earth,” said John Grunsfeld, associate administrator for NASA's Science Mission Directorate. Each probe carries an identical suite of instruments, including an Energetic Particle, Composition, and Thermal Plasma Suite; Electric and Magnetic Field Instrument Suite and Integrated Science; Electric Field and Waves Suite; Radiation Belt Storm Probes Ion Composition Experiment; and Relativistic Proton Spectrometer. RBSP is part of NASA's Living With a Star program and is managed for NASA by the Johns Hopkins University's Applied Physics Laboratory. For more information, see http://rbsp.jhuapl.edu.

NASA's Spacefaring Science Chief Sets a New Course for Mars

Science spoke to John Grunsfeld, head of NASA's Science Mission Directorate, days before what he calls the science event of the decade: the 5 August (PDT) landing of Curiosity on the martian surface.

Newsmakers

This week's Newsmakers are Ed Weiler, who says the Obama Administration's attacks on a Mars mission led to his resignation as head of NASA's science mission last September; Scottish microbiologist Anne Glover, who took office as the first European Chief Scientific Advisor; and Barbara Cannon, the first non-Swedish president of the Royal Swedish Academy of Sciences.

Around the World

In science news around the world this week, a judge has decided that seven Italian earthquake scientists and technicians will be tried on charges of manslaughter, Germany and Switzerland have nixed nuclear energy, NASA's next medium-class science mission will bring back dirt from an asteroid, an amended forest law favorable to ranchers and loggers has brought an outpouring of concern from Brazil's environmentalists, and public health experts in Germany are scrambling to bring the world's deadliest outbreak ever of enterohemorrhagic Escherichia coli under control.

The Lunar Crater Observation and Sensing Satellite (LCROSS) Payload Development and Performance in Flight

The primary objective of the Lunar Crater Observation and Sensing Satellite (LCROSS) was to confirm the presence or absence of water ice in a permanently shad- owed region (PSR) at a lunar pole. LCROSS was classified as a NASA Class D mission. Its payload, the subject of this article, was designed, built, tested and operated to support a condensed schedule, risk tolerant mission approach, a new paradigm for NASA science missions. All nine science instruments, most of them ruggedized commercial-off-the-shelf (COTS), successfully collected data during all in-flight calibration campaigns, and most im- portantly, during the final descent to the lunar surface on October 9, 2009, after 112 days in space. LCROSS demonstrated that COTS instruments and designs with simple interfaces, can provide high-quality science at low-cost and in short development time frames. Building upfront into the payload design, flexibility, redundancy where possible even with the science measurement approach, and large margins, played important roles for this new type of pay- load. The environmental and calibration approach adopted by the LCROSS team, compared to existing standard programs, is discussed. The description, capabilities, calibration and in- flight performance of each instrument are summarized. Finally, this paper goes into depth about specific areas where the instruments worked differently than expected and how the flexibility of the payload team, the knowledge of instrument priority and science trades, and proactive margin maintenance, led to a successful science measurement by the LCROSS payload's instrument complement.

Chandra Observatory marks 10 years in space

NASA's Chandra X‐ray Observatory, originally envisioned as a 5‐year mission, was deployed into an elliptical orbit around Earth 10 years ago, on 23 July 1999. The most powerful X‐ray telescope yet, Chandra has provided a peak into the high‐energy universe and has independently confirmed the existence of dark energy. Martin Weisskopf, Chandra project scientist at NASA's Marshall Space Flight Center, Huntsville, Ala., said discoveries made possible by the observatory “have made dramatic changes to our understanding of the universe and its constituents.”“The Great Observatories program—of which Chandra is a major part—shows how astronomers need as many tools as possible to tackle the big questions out there,” said Ed Weiler, associate administrator of NASA's Science Mission Directorate at NASA Headquarters in Washington. The Hubble Space Telescope, Compton Gamma Ray Observatory, and Spitzer Space Telescope are NASA's other Great Observatories.

MOVERS

Robert Strain has been named the new director of NASA's Goddard Space Flight Center in Greenbelt, Maryland. Strain has led the space department at the Johns Hopkins University Applied Physics Lab in Laurel, Maryland, since 2006 and has worked as a manager for the defense and space industries for more than 25 years. He succeeds Edward Weiler, who was appointed associate administrator for NASA's Science Mission Directorate in May.

Lunar science research proposals sought

NASA's Science Mission Directorate, in cooperation with the agencys Exploration Systems Mission Directorate, is seeking research projects for the NASA Lunar Science Institute. According to the notice, proposals “should include broadly based investigations of the highest quality that address lunar science objectives” and also should align with the institute's goals and objectives. Notices of intent are due 27 June 2008, and proposals are due 29 August 2008.