When NASA’s Space Launch System (SLS) powers into the sky, it must contend with some of the most extreme and complex aerodynamic conditions ever attempted. The ascent phase—especially during transonic and supersonic transitions and through maximum aerodynamic stress—is a crucible for design and engineering. Rather than rely solely on wind tunnels, NASA has increasingly turned to supercomputer-based computational fluid dynamics (CFD) simulations to model the flows around the twin solid rocket boosters, the core stage, and plume interactions. These simulations feed into aerodynamic databases used across vehicle design, structural loads, control algorithms, and safety margins.
The challenge in modeling the flow around SLS boosters is immense. As the vehicle accelerates, shock waves form, flow separation regions emerge, boundary layers evolve, and the rocket plumes themselves strongly interact with the surrounding airstream. Moreover, during events like booster separation, multiple plumes fire simultaneously—up to 22 different exhaust sources in some analyses, combining output from the core engines, boosters, and separation motors. Resolving those off-body interactions, transient flow features, and the coupling between vehicle aerodynamics and plume dynamics demands very high fidelity simulations. The NASA team has used solvers such as OVERFLOW, FUN3D, and Cart3D to explore a wide envelope of flight conditions.
Running these simulations requires massive computational resources. Each case can consume thousands to tens of thousands of core-hours, depending on flow complexity, grid resolution, and the number of interacting plumes. To build a full aerodynamic database that spans multiple Mach numbers, angles of attack, mass fractions, and thrust conditions, NASA runs hundreds to thousands of individual cases. The supercomputers at the NASA Advanced Supercomputing (NAS) facility, including Pleiades, Electra, and others, serve as the backbone of these efforts. Through careful meshing strategies, solver optimizations, and parallel computing techniques, engineers map out pressure distributions, shear stresses, and load profiles for every relevant component of the booster-core assembly.
These simulation results are not academic exercises—they directly inform the safety and performance of SLS missions. The aerodynamics databases are used by structural engineers to assess bending loads, by guidance and control teams to refine trajectory models, and by separation system designers to ensure that boosters detach cleanly without risking collision with the core. When flight data come in, the models themselves can be validated and refined, closing the loop between simulation and real world performance. As SLS evolves—especially with future variants and heavier payloads—the simulation infrastructure will scale accordingly, enabling continuous improvements in confidence, margin, and mission success.
Video credit: NASA/NAS/Gerrit-Daniel Stich, Michael Barad, Timothy Sandstrom, Derek Dalle
OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) is a NASA asteroid-study and sample-return mission. The mission’s primary goal is to obtain a sample of at least 60 g (2.1 oz) from 101955 Bennu, a carbonaceous near-Earth asteroid, and return the sample to Earth for a detailed analysis. The material returned is expected to enable scientists to learn more about the formation and evolution of the Solar System, its initial stages of planet formation, and the source of organic compounds that led to the formation of life on Earth.
OSIRIS-REx was launched on 8 September 2016, flew past Earth on 22 September 2017, and rendezvoused with Bennu on 3 December 2018. It spent the next several months analyzing the surface to find a suitable site from which to extract a sample. On 20 October 2020, OSIRIS-REx touched down on Bennu and successfully collected a sample. Though some of the sample escaped when the flap that should have closed the sampler head was jammed open by larger rocks, NASA is confident that they were able to retain between 400 g and over 1 kg of sample material, well in excess of the 60 g (2.1 oz) minimum target mass. OSIRIS-REx is expected to return with its sample to Earth on 24 September 2023 and subsequently start its new mission to study 99942 Apophis as OSIRIS-APEX (‘APophis EXplorer’), arriving at that asteroid in 2029.
Bennu was chosen as the target of study because it is a “time capsule” from the birth of the Solar System. Bennu has a very dark surface and is classified as a B-type asteroid, a sub-type of the carbonaceous C-type asteroids. Such asteroids are considered primitive, having undergone little geological change from their time of formation. In particular, Bennu was selected because of the availability of pristine carbonaceous material, a key element in organic molecules necessary for life as well as representative of matter from before the formation of Earth. Organic molecules, such as amino acids, have previously been found in meteorite and comet samples, indicating that some ingredients necessary for life can be naturally synthesized in outer space.
The cost of the mission is approximately US$800 million, not including the Atlas V launch vehicle, which is about US$183.5 million. It is the third planetary science mission selected in the New Frontiers program, after Juno and New Horizons. The principal investigator is Dante Lauretta from the University of Arizona. If successful, OSIRIS-REx will be the first United States spacecraft to return samples from an asteroid. The Japanese probe Hayabusa returned samples from 25143 Itokawa in 2010, and Hayabusa2 returned from 162173 Ryugu in December 2020. On 10 May 2021, OSIRIS-REx successfully completed its departure from Bennu and began its two-year return to Earth.
NASA’s Starling mission is advancing the readiness of various technologies for cooperative groups of spacecraft – also known as distributed missions, clusters, or swarms. Starling will demonstrate technologies to enable multipoint science data collection by several small spacecraft flying in swarms. The six-month mission will use four CubeSats in low-Earth orbit to test four technologies that let spacecraft operate in a synchronized manner without resources from the ground. The technologies will advance the following capabilities: swarm maneuver planning and execution, communications networking, relative navigation, autonomous coordination between spacecraft.
The Starling mission will test whether the technologies work as expected, what their limitations are, and what developments are still needed for CubeSat swarms to be successful.
Distributed spacecraft are advantageous because they can act in unison to achieve objectives. Incorporating autonomy allows these missions to act cooperatively with minimal oversight from the ground. Autonomy ensures that a mission continues to perform through periods when communications with a spacecraft from the ground is temporarily unavailable because of distance or location. Spacecraft swarms operating at great distances from the Earth must act more autonomously due to the delays in time communicating with Earth ground stations.
Clustering satellites into a swarm requires planning and executing multiple maneuvers for each spacecraft. Managing these operations from the ground becomes impractical as the size of the swarm grows or the time delay in communicating with the spacecraft increases. The Starling mission will test technologies that traditionally run ground-oriented operations but are now shifted to operate onboard the spacecraft.
Having the spacecraft in a swarm operate autonomously is essential to making distributed spacecraft missions affordable and highly scaleable. Starling is a first step in developing this new mission architecture that could eventually allow for autonomous swarms of many spacecraft and at greater distances from Earth.
The four 6-unit CubeSats (each about the size of two stacked cereal boxes) will fly in a Sun-synchronous orbit more than 300 miles above Earth and no more than 170 miles apart from each other. The spacecraft will fly in two formations. First, they will begin in line, or in-train, like a string of pearls. Then, the CubeSats will move out of the in-train configuration and into a set of stable relative orbits known as passive safety ellipses.
The following four technologies will be tested:
Reconfiguration and Orbit Maintenance Experiments Onboard (ROMEO): In each phase, cluster flight control software will initially operate in shadow mode, autonomously planning maneuvers while the CubeSats are controlled from the ground. Once validated, ROMEO will demonstrate execution of swarm maintenance maneuvers from aboard the spacecraft without ground intervention. The performance of those maneuvers will then be evaluated.
Mobile Ad-hoc Network (MANET): The CubeSats will be able to communicate with each other via two-way S-band crosslink radios/antennas, adapting a ground-based network protocol for reliable space communication across any spacecraft node within the swarm. If one spacecraft communications node fails, the communications route automatically reconfigures to maintain full communication capabilities for the remaining operational swarm of spacecraft.
Starling Formation-Flying Optical Experiment (StarFOX): Using commercial star trackers, which are onboard cameras that measure the position of stars, each spacecraft determines its own orientation relative to the stars. An advanced navigation algorithm utilizes this orientation data and star tracker images to visually detect and track the other three spacecraft within the swarm to perform relative-position knowledge tests. The goal is for each spacecraft to achieve onboard awareness of its location as well as the location of the other three spacecraft.
Distributed Spacecraft Autonomy (DSA): This experiment will demonstrate autonomous monitoring of Earth’s ionosphere, the layer between our atmosphere and the beginning of space, with a spacecraft swarm. This is intended as a representative measurement to demonstrate autonomous reactive operations for future missions. Starling’s dual-band GPS receivers are used to measure the density of atmospheric regions. Each orbiting Starling spacecraft constantly changes position relative to the atmospheric phenomenon and the GPS satellites. Therefore, the most interesting source of information changes over time, requiring changes to the monitoring strategy in response to observations. DSA onboard software will autonomously coordinate the selection of the best GPS signals, across all Starling spacecraft, to accurately capture regions of higher or lower ionospheric density. This is accomplished by first sharing information over the crosslink network to maintain a consistent state, then selecting the GPS signals to prioritize and share in the future. The ability to evaluate data as it is collected, balance promising observations with coverage to ensure other interesting information is not missed, and autonomously coordinate measurements, is an enabling technology for future science missions.
It’s important to note that although Starling is being tested in low-Earth orbit, the technologies apply equally as well to deep space applications. In the future, constellation-like swarms of autonomously operating CubeSats could provide NASA and commercial missions in deep space with navigation services akin to GPS and communications relays provided by Earth’s network of communications satellites. Distributed spacecraft can also work together to collect multi-point science data and prepare for exploration missions by positioning multiple small spacecraft to function as one very large observation instrument. This could support the identification of resources for long-term presence on the Moon. Another example of this cooperative work might include telescopes mounted on multiple small spacecraft and trained on a particular observation target, creating a larger field of view than possible with a single telescope.
Inspired by the Renaissance vision of Leonardo da Vinci, NASA is presently preparing its scientific return to Venus’ atmosphere and surface with a mission known as the “Deep Atmosphere of Venus Investigation of Noble gases, Chemistry, and Imaging” (DAVINCI).
The DAVINCI mission will “take the plunge” into Venus’ enigmatic history using an instrumented deep atmosphere probe spacecraft that will carry five instruments for measuring the chemistry and environments throughout the clouds and to the surface, while also conducting the first descent imaging of a mountain system on Venus known as Alpha Regio, which may represent an ancient continent. In addition, the DAVINCI mission includes two science flybys of Venus during which it will search for clues to mystery molecules in the upper cloud deck while also measuring the rock types in some of Venus highland regions.
All of these new and unique measurements will make the ‘exoplanet next door’ into a key place for understanding Earth and Venus sized exoplanets that may have similar histories to our sister planet. DAVINCI will pave the way for a series of missions by NASA and ESA in the 2030’s by opening the frontier as it searches for clues to whether Venus harbored oceans and how its atmosphere-climate system evolved over billions of years. DAVINCI’s science will address questions about habitability and how it could be “lost” as rocky planets evolve over time. NASA’s Goddard Space Flight center leads the DAVINCI Mission as the PI institution.
Credit: NASA’s Goddard Space Flight Center/James Tralie (ADNET): Lead Producer, Lead Editor/Giada Arney (NASA): Narrator/Walt Feimer (KBRwyle): Animator/Jonathan North (KBRwyle): Animator/Michael Lentz (KBRwyle): Animator/Krystofer Kim (KBRwyle): Animator/James Garvin (NASA, Chief Scientist Goddard): Scientist/Music: “Blackened Skies” by Enrico Cacace and Lorenzo Castellarin of Universal Production Music
SpaceX’s Falcon 9 rocket, with the company’s uncrewed Dragon spacecraft on top, lifted off from NASA’s Kennedy Space Center in Florida.
Loaded with scientific experiments and supplies, the unpiloted SpaceX CRS-27 cargo ship automatically docked to the International Space Station’s forward port of the Harmony module March 16. The SpaceX resupply craft will remain on orbit for a month-long visit.
This video chronicles solar activity from Aug. 12 to Dec. 22, 2022, as captured by NASA’s Solar Dynamics Observatory (SDO). From its orbit in space around Earth, SDO has steadily imaged the Sun in 4K x 4K resolution for nearly 13 years. This information has enabled countless new discoveries about the workings of our closest star and how it influences the solar system.
With a triad of instruments, SDO captures an image of the Sun every 0.75 seconds. The Atmospheric Imaging Assembly (AIA) instrument alone captures images every 12 seconds at 10 different wavelengths of light. This 133-day time lapse showcases photos taken at a wavelength of 17.1 nanometers, which is an extreme-ultraviolet wavelength that shows the Sun’s outermost atmospheric layer: the corona. Compiling images taken 108 seconds apart, the movie condenses 133 days, or about four months, of solar observations into 59 minutes. The video shows bright active regions passing across the face of the Sun as it rotates. The Sun rotates approximately once every 27 days. The loops extending above the bright regions are magnetic fields that have trapped hot, glowing plasma. These bright regions are also the source of solar flares, which appear as bright flashes as magnetic fields snap together in a process called magnetic reconnection.
While SDO has kept an unblinking eye pointed toward the Sun, there have been a few moments it missed. Some of the dark frames in the video are caused by Earth or the Moon eclipsing SDO as they pass between the spacecraft and the Sun. Other blackouts are caused by instrumentation being down or data errors. SDO transmits 1.4 terabytes of data to the ground every day. The images where the Sun is off-center were observed when SDO was calibrating its instruments.
SDO and other NASA missions will continue to watch our Sun in the years to come, providing further insights about our place in space and information to keep our astronauts and assets safe.
Music Credit: The music is a continuous mix from Lars Leonhard’s “Geometric Shapes” album, courtesy of the artist.
Credit: NASA’s Goddard Space Flight Center/Scott Wiessinger (PAO): Lead Producer/Tom Bridgman (SVS): Lead Visualizer/Scott Wiessinger (PAO): Editor
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