SpaceX Starlink launched and subsequently lost 38 of 49 satellites because of enhanced neutral density associated with a geomagnetic storm on 3 February 2022. Fang et al. (Space Weather, 20:e2022SW003193, [1]) examine the space weather conditions related to the satellite loss, based on observations, forecasts, and numerical simulations from the National Oceanic and Atmospheric Administration (NOAA) Space Weather Prediction Center (SWPC). Working closely with the Starlink team, the thermospheric densities along the satellite orbits were estimated and the neutral density increase leading to the satellite loss was investigated. Simulation results suggest that the NRLMSIS-00 neutral density estimates used by the Starlink team in pre-launch Monte Carlo analysis tended to underestimate the neutral density compared to predictions from the operational WAM-IPE physics-based model during the geomagnetic storm. The numerical simulation indicated this minor to moderate geomagnetic storm sufficed to create 50

The current operational dimension available for space weather analysis and operations is not suitable for deep space exploration.As NASA plans for missions beyond the Low Earth Orbit (LEO), new advancements in modeling, observations, and communications are needed to establish a suitable monitoring and protection environment for the missions and the crew.The initial step is to establish multiple observational points that will improve the current analysis/modeling capabilities and extend them to deep space exploration missions.We summarize the value of multiple observational points, outline the current gaps (with examples) in providing operational space weather support for deep space exploration, and propose ideas for missions and international collaborations that will address these existing gaps.These proposed missions and collaborations will be essential to ensure a successful future for deep space exploration.

NOAA has a research priority to acquire observations of solar wind parameters at sub-L1 points along the Sun-Earth line.Operational measurements at sub-L1 would improve geomagnetic storm alert lead times.We present a proposed mission based on the Solar Cruiser mission architecture that can meet the first step of these research observations using solar sail propulsion technology.The higher characteristic acceleration available from using a solar sail overcomes the difficult duty station requirement at sub-L1.The mission will also fly a science payload to observe the solar wind density, velocity, temperature and the interplanetary magnetic field at sub-L1.The primary mission objective is to demonstrate that a spacecraft using solar sail propulsion technology with a science payload enables in-situ plasma and magnetic field observations at sub-L1.

Abstract The National Oceanic and Atmospheric Administration's Space Weather Prediction Center (NOAA/SWPC) issues several solar radiation storm products: the long standing proton Warnings and Alerts that are based on particle intensity levels observed by the Geostationary Operational Environmental Satellites; and the more recent International Civil Aviation Organization (ICAO) radiation advisories which specify effective dose rates at aviation flight levels. SWPC ICAO advisories are supported by the U.S. Federal Aviation Administration (FAA) CARI‐7A model. In this paper we use CARI‐7A modeling results for the Ground Level Enhancement 69 (GLE69) solar radiation storm which occurred on the 20th of January 2005 to demonstrate the ICAO advisory format. For the onset and peak of GLE69, we find that a severe (SEV) radiation advisory would have been issued for altitudes above 32,000 ft, for polar and mid latitude regions of the northern and southern hemisphere. At lower altitudes, down to 25,000 ft, the moderate (MOD) radiation threshold would have been exceeded. In total, 10 ICAO radiation advisories would have been issued over 6.5 hr. From the retrospective modeling of GLE69, and feedback from users, we identify ways in which the ICAO advisories should be improved.

Abstract On 3 February 2022, SpaceX Starlink launched and subsequently lost 38 of 49 satellites due to enhanced neutral density associated with a geomagnetic storm. This study examines the space weather conditions related to the satellite loss, based on observations, forecasts, and numerical simulations from the National Oceanic and Atmospheric Administration Space Weather Prediction Center (SWPC). Working closely with the Starlink team, the thermospheric densities along the satellite orbits were estimated and the neutral density increase leading to the satellite loss was investigated. Simulation results suggest that during the geomagnetic storm, pre‐launch Monte Carlo analyses performed by the Starlink team using empirical neutral density inputs from NRLMSISE‐00 tended to underestimate the impact relative to predictions from the operational coupled Whole Atmosphere Model and Ionosphere Plasmasphere Electrodynamics physics‐based model. The numerical simulation indicated this minor to moderate geomagnetic storm was sufficient to create 50%–125% density enhancement at altitudes ranging between 200 and 400 km. With the increasing solar activity of Solar Cycle 25, satellites in low‐Earth orbit are expected to experience an increasing number of thermospheric expansion events. Currently, no alerts and warnings issued by SWPC are focused on satellite users concerned with atmospheric drag and related applications. Thus, during geomagnetic storms, it is crucial to establish suitable alerts and warnings based on neutral density predictions to provide users guidance for preventing satellite losses due to drag and to aid in collision avoidance calculations.

Abstract The effects of solar radiation storms at Earth are felt across a number of technology‐based industries. Energetic particles present during these storms impact electrical components on spacecraft, disrupt high frequency radio communications, and pose a radiation risk for passengers and crew on polar flight routes, as well as for astronauts. An essential aspect of space weather forecasting is therefore to predict the occurrence and properties of a solar proton event before it occurs. In this study, we review radiation storm products issued by the National Oceanic and Atmospheric Administration's Space Weather Prediction Center (SWPC) during Solar Cycles 23 and 24. These include three‐day probabilistic proton event forecasts and short‐term Warning and Alert hazard products. We present performance metrics and forecast skill scores for SWPC probabilistic forecasts and Warning products, which can be used as a benchmark for assessing the performance of radiation storm forecast models.

Accurate forecasting of the arrival time and subsequent geomagnetic impacts of Coronal Mass Ejections (CMEs) at Earth is an important objective for space weather forecasting agencies. Recently, the CME Arrival and Impact working team has made significant progress towards defining community-agreed metrics and validation methods to assess the current state of CME modeling capabilities. This will allow the community to quantify our current capabilities and track progress in models over time. Firstly, it is crucial that the community focuses on the collection of the necessary metadata for transparency and reproducibility of results. Concerning CME arrival and impact we have identified 6 different metadata types: 3D CME measurement, model description, model input, CME (non-)arrival observation, model output data and metrics and validation methods. Secondly, the working team has also identified a validation time period, where all events within the following two periods will be considered: 1 January 2011-31 December 2012 and January 2015-31 December 2015. Those two periods amount to a total of about 100 hit events at Earth and a large amount of misses. Considering a time period will remove any bias in selecting events and the event set will represent a sample set that will not be biased by user selection. Lastly, we have defined the basic metrics and skill scores that the CME Arrival and Impact working team will focus on.

A workshop was recently held at Nagoya University (2017 October 31–November 2), sponsored by the Center for International Collaborative Research, at the Institute for Space-Earth Environmental Research, Nagoya University, Japan, to quantitatively compare the performance of today’s operational solar flare forecasting facilities. Building upon Paper I of this series, in Paper II we described the participating methods for this latest comparison effort, the evaluation methodology, and presented quantitative comparisons. In this paper, we focus on the behavior and performance of the methods when evaluated in the context of broad implementation differences. Acknowledging the short testing interval available and the small number of methods available, we do find that forecast performance: (1) appears to improve by including persistence or prior flare activity, region evolution, and a human “forecaster in the loop”; (2) is hurt by restricting data to disk-center observations; (3) may benefit from long-term statistics but mostly when then combined with modern data sources and statistical approaches. These trends are arguably weak and must be viewed with numerous caveats, as discussed both here and in Paper II. Following this present work, in Paper IV (Park et al. 2019) we will present a novel analysis method to evaluate temporal patterns of forecasting errors of both types (i.e., misses and false alarms). Hence, most importantly, with this series of papers, we demonstrate the techniques for facilitating comparisons in the interest of establishing performance-positive methodologies.

Solar flares are extremely energetic phenomena in our Solar System. Their impulsive, often drastic radiative increases, in particular at short wavelengths, bring immediate impacts that motivate solar physics and space weather research to understand solar flares to the point of being able to forecast them. As data and algorithms improve dramatically, questions must be asked concerning how well the forecasting performs; crucially, we must ask how to rigorously measure performance in order to critically gauge any improvements. Building upon earlier-developed methodology (Barnes et al, 2016, Paper I), international representatives of regional warning centers and research facilities assembled in 2017 at the Institute for Space-Earth Environmental Research, Nagoya University, Japan to - for the first time - directly compare the performance of operational solar flare forecasting methods. Multiple quantitative evaluation metrics are employed, with focus and discussion on evaluation methodologies given the restrictions of operational forecasting. Numerous methods performed consistently above the "no skill" level, although which method scored top marks is decisively a function of flare event definition and the metric used; there was no single winner. Following in this paper series we ask why the performances differ by examining implementation details (Leka et al. 2019, Paper III), and then we present a novel analysis method to evaluate temporal patterns of forecasting errors in (Park et al. 2019, Paper IV). With these works, this team presents a well-defined and robust methodology for evaluating solar flare forecasting methods in both research and operational frameworks, and today's performance benchmarks against which improvements and new methods may be compared.

Between 4 and 10 September 2017, multiple solar eruptions occurred from active region AR12673. NOAA's and NASA's well‐instrumented spacecraft observed the evolution of these geoeffective events from their solar origins, through the interplanetary medium, to their geospace impacts. The 6 September X9.3 flare was the largest to date for the nearly concluded solar cycle 24 and, in fact, the brightest recorded since an X17 flare in September 2005, which occurred during the declining phase of solar cycle 23. Rapid ionization of the sunlit upper atmosphere occurred, disrupting high‐frequency communications in the Caribbean region while emergency managers were scrambling to provide critical recovery services caused by the region's devastating hurricanes. The 10 September west limb eruption resulted in the first solar energetic particle event since 2012 with sufficient flux and energy to yield a ground level enhancement. Spacecraft at L1, including DSCOVR, sampled the associated interplanetary coronal mass ejections minutes before their collision with Earth's magnetosphere. Strong compression and erosion of the dayside magnetosphere occurred, placing geosynchronous satellites in the magnetosheath. Subsequent geomagnetic storms produced magnificent auroral displays and elevated hazards to power systems. Through the lens of NOAA's space weather R‐S‐G storm scales, this event period increased hazards for systems susceptible to elevated “radio blackout” (R3‐strong), “solar radiation storm” (S3‐strong), and “geomagnetic storm” (G4‐severe) conditions. The purpose of this paper is to provide an overview of the September 2017 space weather event, and a summary of its consequences, including forecaster, post‐event analyst, and communication operator perspectives.