For more than a decade, Tristan McKnight has been a driving force behind some of NASA’s most iconic events, orchestrating the behind-the-scenes magic that brings each historic moment to life while sharing the agency’s advancements with the public. 

As a multimedia producer on the audiovisual team at Johnson Space Center in Houston, McKnight produces and directs live broadcasts and manages event planning, coordination, and execution. From overseeing resources, mitigating risks, and communicating with stakeholders, he ensures every detail aligns seamlessly.  

McKnight has played an integral role in the audiovisual team’s coverage of major events including the Artemis II crew announcement, where NASA revealed the astronauts who will venture around the Moon and back, to Johnson’s 2023 Open House, which celebrated the agency’s 65th anniversary and the 25th anniversary of the International Space Station’s operations. These achievements highlight key milestones in human space exploration.  

A standout achievement was contributing to the Dorothy Vaughan Center in Honor of the Women of Apollo naming ceremony, held on the eve of the 55th anniversary of the Apollo 11 Moon landing. The event honored the unsung heroes who made humanity’s first steps on the Moon possible. 

The team’s dedication and passion are a testament to their commitment to sharing NASA’s legacy with the world. 

“Not only have these events been impactful to Johnson, but they have also resonated across the entire agency,” McKnight said. “That is what I’m most proud of!” 

One of McKnight’s most memorable events was the 2023 “Back in the Saddle,” an annual tradition designed to refocus Johnson’s workforce at the start of a new year and renew the center’s commitment to safety and mission excellence. McKnight recalled how the speaker transformed Johnson’s Teague Auditorium into a venue filled with drum kits, inspiring messages, and lighting displays. Each audience member, drumsticks in hand, participated in a lesson on teamwork and synchronization to create a metaphor for working in harmony toward a shared goal. 

Like many high-achieving professionals. McKnight has faced moments of self-doubt. Then he realized that he is exactly where he is supposed to be. “As I settled into my role, I recognized that my contributions matter and simply being true to who I am adds value to the Johnson community,” he said.  

Each day brings its own set of challenges, ranging from minor issues like communication gaps and scheduling conflicts to major obstacles like technology failures. One of McKnight’s most valuable lessons is recognizing that there is no one-size-fits-all solution, and each situation requires a thoughtful analysis. 

McKnight understands the importance of the “check-and double-check,” a philosophy he considers crucial when working with technology. “Taking the extra time to do your due diligence, or even having someone else take a look, can make all the difference,” he said. 

“The challenges I’ve faced helped me grow as a problem solver and taught me valuable lessons on resilience and adaptability in the workplace,” he said. McKnight approaches obstacles with a level head, focusing on effective solutions rather than dwelling on the problem. 

As humanity looks to the stars, McKnight is energized about the future of exploration, particularly advancements in spacesuit and rocket technology that will enable us to travel farther, faster, and safer than ever before. His work, though grounded on Earth, helps create the inspiration that fuels these bold endeavors. 

“My hope for the next generation is that they dive deeper into their curiosity—exploring not only the world around them but also the Moon, planets, and beyond,” he said. “I also hope they carry forward the spirit of resilience and a commitment to making the world a better place for all.” 

When NASA’s Artemis IV astronauts journey to the Moon, they will make the inaugural visit to Gateway, humanity’s first space station in lunar orbit. Shown here, technicians carefully guide HALO (Habitation and Logistics Outpost)—a foundational element of Gateway—onto a stand in the cleanroom at Thales Alenia Space in Turin, Italy. The element’s intricate structure, designed to support astronauts and science in lunar orbit, has entered the cleanroom after successfully completing a series of rigorous environmental stress tests.

In the cleanroom, technicians will make final installations before preparing the module for transport to the United States, a key milestone on its path to launch. This process includes installing and testing valves and hatches, performing leak checks, and integrating external secondary structures. Once these steps are finished, the module will be packaged for shipment to Gilbert, Arizona, where Northrop Grumman will complete its outfitting.

As one of Gateway’s four pressurized modules, HALO will provide Artemis astronauts with space to live, work, conduct scientific research, and prepare for missions to the lunar surface. The module will also support internal and external science payloads, including a space weather instrument suite attached via a Canadian Space Agency Small Orbital Replacement Unit Robotic Interface, host the Lunar Link communications system developed by European Space Agency, and offer docking ports for visiting vehicles, including lunar landers and NASA’s Orion spacecraft.

Developed in collaboration with industry and international partners, Gateway is a cornerstone of NASA’s Artemis campaign to advance science and exploration on and around the Moon in preparation for the next giant leap: the first human missions to Mars.

Editor’s note: This advisory was updated on Feb. 12, 2025, to add the target launch time.

Media accreditation is open for the launch of NASA’s 10th rotational mission of a SpaceX Falcon 9 rocket and Dragon spacecraft, carrying astronauts to the International Space Station for a science expedition. The agency’s SpaceX Crew-10 mission is targeting launch at 7:48 p.m. EDT on Wednesday, March 12, from Launch Complex 39A at NASA’s Kennedy Space Center in Florida.

The launch will carry NASA astronauts Anne McClain as commander and Nichole Ayers as pilot, along with JAXA (Japan Aerospace Exploration Agency) astronaut Takuya Onishi and Roscosmos cosmonaut Kirill Peskov as mission specialists. This is the first spaceflight for Ayers and Peskov, and the second mission to the orbiting laboratory for McClain and Onishi.

Media accreditation deadlines for the Crew-10 launch as part of NASA’s Commercial Crew Program are as follows:

• International media without U.S. citizenship must apply by 11:59 p.m. on Thursday, Feb. 13.
• U.S. media and U.S. citizens representing international media organizations must apply by 11:59 p.m. EST on Sunday, Feb. 23.

All accreditation requests must be submitted online at:

https://media.ksc.nasa.gov

NASA’s media accreditation policy is online. For questions about accreditation or special logistical requests, email: ksc-media-accreditat@mail.nasa.gov. Requests for space for satellite trucks, tents, or electrical connections are due by Friday, Feb. 21.

For other questions, please contact NASA Kennedy’s newsroom at: 321-867-2468.

Para obtener información sobre cobertura en español en el Centro Espacial Kennedy o si desea solicitar entrevistas en español, comuníquese con Antonia Jaramillo: 321-501-8425, o Messod Bendayan: 256-930-1371.

For launch coverage and more information about the mission, visit:

https://www.nasa.gov/commercialcrew

-end-

Joshua Finch / Claire O’Shea
Headquarters, Washington
202-358-1100
joshua.a.finch@nasa.gov / claire.a.o’shea@nasa.gov

Steve Siceloff / Stephanie Plucinsky
Kennedy Space Center, Florida
321-867-2468
steven.p.siceloff@nasa.gov / stephanie.n.plucinsky@nasa.gov

Kenna Pell
Johnson Space Center, Houston
281-483-5111
kenna.m.pell@nasa.gov

You would not expect to see NASA at a car show—but that’s exactly where Johnson Space Center employees were from Jan. 29 to Feb. 2, 2025, driving the future of space exploration forward. 

At the Houston AutoBoative Show, a fusion of the auto and boat show, NASA rolled out its Artemis exhibit at NRG Center for the first time, introducing vehicle enthusiasts to the technologies NASA and commercial partners will use to explore more of the lunar surface than ever before. 

The Artemis exhibit stood alongside some of the world’s most advanced cars and boats, offering visitors an up-close look at lunar terrain vehicle mockups from Astrolab, Intuitive Machines, and Lunar Outpost. Later this year, NASA will select the rover that will fly to the Moon as humanity prepares for the next giant leap. 

In addition to the rovers, the exhibit featured a mockup of JAXA’s (Japan Aerospace Exploration Agency) pressurized rover, designed as a mobile habitat for astronauts, and Axiom Space’s lunar spacesuit, developed for Artemis III astronauts. 

These capabilities will allow astronauts to explore, conduct science research, and live and work on the lunar surface.  

Johnson Director Vanessa Wyche visited the Artemis exhibit to highlight the importance of these technologies in advancing lunar exploration. Every lesson learned on the Moon will help scientists and engineers develop the strategies, technologies, and experience needed to send astronauts to Mars.  

“By bringing the excitement of lunar exploration to the AutoBoative Show, NASA aims to inspire the next generation of explorers to dream bigger, push farther, and help shape humanity’s future in space,” Wyche said.  

NASA’s Artemis campaign is setting the stage for long-term human exploration, working with commercial and international partners to establish a sustained presence on the Moon before progressing to Mars. 

To make this vision a reality, NASA is developing rockets, spacecraft, landing systems, spacesuits, rovers, habitats, and more.  

Some of the key elements on display at the show included:

• The Orion spacecraft – Designed to take astronauts farther into deep space. Orion will launch atop NASA’s Space Launch System (SLS) rocket, carrying the crew to the Moon on Artemis missions and safely returning them to Earth.

• Lunar terrain vehicles – Developed to transport astronauts across the rugged lunar surface or be remotely operated. NASA recently put these rover mockups to the test at Johnson, where astronauts and engineers, wearing spacesuits, ran through critical maneuvers, tasks, and emergency drills—including a simulated crew rescue.

• Next-gen spacesuits and tools – Through Johnson’s Extravehicular Activity and Human Surface Mobility Program, astronauts’ gear and equipment are designed to ensure safety and efficiency while working on the Moon’s surface.

Guests had the chance to step into the role of an astronaut with interactive experiences like: 

• Driving a lunar rover simulator – Testing their skills at the wheel of a virtual Moon rover. 

• Practicing a simulated Orion docking – Experiencing the precision needed to connect to Gateway in lunar orbit. 

• Exploring Artemis II and III mission roadmaps – Learning about NASA’s upcoming missions and goals. 

Attendees also discovered how American companies are delivering science and technology to the Moon through NASA’s Commercial Lunar Payload Services initiative. 

“Everyone can relate to exploration, so it was great to teach people the importance lunar rovers will have on astronauts’ abilities to explore more of the lunar surface while conducting science,” said Victoria Ugalde, communications strategist for the Extravehicular Activity and Human Surface Mobility Program, who coordinated the lunar rovers’ appearance at the show. 

Check out the rovers contracted to develop lunar terrain vehicle capabilities below.

Measuring water loss from space

This study showed that the International Space Station’s ECOSTRESS instrument estimates of evapotranspiration (transfer of water to the atmosphere from Earth’s surface and plants) are comparable to ground-based reference values. This finding suggests space measurements could provide guidance for improved water management on large scales.

Worsening droughts due to climate change require better water management. Evapotranspiration is a critical part of the hydrologic cycle, but data are lacking on local water conditions and demands. California’s Eastern Municipal Water District uses the ground-based California Irrigation Management Information System to track evapotranspiration, but it has limited spatial coverage and consistency. Space-based estimates could be better and more consistent.

Four-legged robotic retrievers

Space station crew members successfully located and retrieved an object in a simulated Mars environment using a remotely controlled four-legged robot, Bert. Legged robots could provide the ability to explore and survey different extraterrestrial surfaces on future missions.

On uneven lunar and planetary surfaces, robots with legs could explore areas inaccessible to wheeled rovers. Surface Avatar, an investigation from ESA (European Space Agency), evaluated remote control of multiple robots in space, providing information on how human operators respond to physical feedback (such as feeling a bump when a robot arm makes contact) and identifying challenges for orbit-to-ground remote operation of robots. The German Aerospace Center is developing Bert.

Technology supports atmospheric studies

Researchers found that the Compact Thermal Imager (CTI) on the space station produced scientifically useful imagery of atmospheric phenomena, including gravity waves, clouds, and volcanic plumes. This technology could change current practices and instrument design for remote sensing of Earth from space.

The CTI is mounted on hardware for Robotic Refueling Mission 3, which tested technology for the robotic transfer and storage of cryogenic fluids in microgravity. The station’s orbit provides near-global coverage and CTI has reduced size, energy use, and cost. Its images can measure fires, ice sheets, glaciers, and snow surface temperatures on the ground and the transfer of water from soil and plants into the atmosphere.

For astronauts aboard the International Space Station, staying connected to loved ones and maintaining a sense of normalcy is critical. That is where Tandra Gill Spain, a computer resources senior project manager in NASA’s Avionics and Software Office, comes in. Spain leads the integration of applications on Apple devices and the hardware integration on the Joint Station Local Area Network, which connects the systems from various space agencies on the International Space Station. She also provides technical lead support to the Systems Engineering and Space Operations Computing teams and certifies hardware for use on the orbiting laboratory. 

Spain shares about her career with NASA and more. Read on to learn about her story, her favorite project, and the advice she has for the next generation of explorers. 

Where are you from? 

I am from Milwaukee, Wisconsin. 

Tell us about your role at NASA. 

I am the Apple subsystem manager where I lead the integration of applications on Apple devices as well as the hardware integration on the Joint Station Local Area Network. We use a variety of different software but I work specifically with our Apple products. I also provide technical lead support to the Systems Engineering and Space Operations Computing teams. In addition, I select and oversee the certification of hardware for use on the International Space Station, and I research commonly used technology and assess applicability to space operations.   

How would you describe your job to family or friends who may not be familiar with NASA? 

I get the opportunity to provide the iPads and associated applications that give astronauts the resources to access the internet. Having access to the internet affords them the opportunity to stay as connected as they desire with what is going on back home on Earth (e.g., stream media content, stay in touch with family and friends, and even pay bills). I also provide hardware such as Bluetooth speakers, AirPods, video projectors, and screens. 

How long have you been working for NASA? 

I have been with the agency for 30 years, including 22 years as a contractor. 

What advice would you give to young individuals aspiring to work in the space industry or at NASA? 

I have found that there is a place for just about everyone at NASA, therefore, follow your passion.  Although many of us are, you don’t have to be a scientist or engineer to work at NASA. Yearn to learn.  Pause and listen to those around you. You don’t know what you don’t know, and you will be amazed what gems you’ll learn in the most unexpected situations. 

Additionally, be flexible and find gratitude in every experience. Many of the roles that I’ve had over the years didn’t come from a well-crafted, laid-out plan that I executed, but came from taking advantage of the opportunities that presented themselves and doing them to the best of my ability. 

What was your path to NASA? 

I moved to Houston to work at NASA’s Johnson Space Center immediately upon graduating from college. 

Is there someone in the space, aerospace, or science industry that has motivated or inspired you to work for the space program? Or someone you discovered while working for NASA who inspires you?  

I spent over half of my career in the Astronaut Office, and I’ve been influenced in different ways by different people, so it wouldn’t be fair to pick just one! 

What is your favorite NASA memory? 

I’ve worked on so many meaningful projects, but there are two recent projects that stand out.

Humans were not created to be alone, and connection is extremely important. I was able to provide a telehealth platform for astronauts to autonomously video conference with friends and family whenever an internet connection is available. Prior to having this capability, crew were limited to one scheduled video conference a week. It makes me emotional to think that we have moms and dads orbiting the Earth on the space station and they can see their babies before they go to bed, when they wake up in the morning, or even in the middle of the night if needed.  

In addition, since iPads are used for work as well as personal activities on station, it is important for my team to be able to efficiently keep the applications and security patches up to date. We completed the software integration and are in the process of wrapping up the certification of the Mac Mini to provide this capability. This will allow us to keep up with all software updates that Apple releases on a regular basis and minimize the amount of crew and flight controller team time associated with the task by approximately 85%. 

What do you love sharing about station? What’s important to get across to general audiences to help them understand the benefits to life on Earth? 

When I speak to the public about the space station, I like to compare our everyday lives on Earth to life on the station and highlight the use of technology to maintain the connection to those on Earth. For example, most people have a phone. Besides making a phone call, what do you use your phone for? It is amazing to know that the same capabilities exist on station, such as using apps, participating in parent teacher conferences, and more. 

If you could have dinner with any astronaut, past or present, who would it be? 

I would have dinner with NASA astronaut Ron McNair. He graduated from the same university as I did, and I’ve heard great stories about him. 

Do you have a favorite space-related memory or moment that stands out to you? 

As I mentioned previously, human connection is extremely important. As an engineer in the Astronaut Office, I worked on a project that provided more frequent email updates when Ku-Band communication was available. Previously, email was synced two to three times a day, and less on the weekend. When the capability went active, I sent the first email exchange. 

What are some of the key projects you’ve worked on during your time at NASA? What have been your favorite?  

There have been so many projects over the past 30 years that I don’t think I could select just one. There is something however, that I’ve done on many occasions that has brought me pure joy, which is attending outreach events as Johnson’s “Cosmo” mascot, especially Houston Astros games.    

What are your hobbies/things you enjoy outside of work? 

I enjoy crafting, traveling, mentoring students in Pearland Independent School District, spending time with family, and my Rooted Together community. 

Day launch or night launch?  

Night launch! 

Favorite space movie? 

Star Wars (the original version) 

NASA “worm” or “meatball” logo? 

Meatball 

Every day, we’re conducting exciting research aboard our orbiting laboratory that will help us explore further into space and bring benefits back to people on Earth. You can keep up with the latest news, videos, and pictures about space station science on the Station Research & Technology news page. It’s a curated hub of space station research digital media from Johnson and other centers and space agencies.  

Sign up for our weekly email newsletter to get the updates delivered directly to you.  

Follow updates on social media at @ISS_Research on Twitter, and on the space station accounts on Facebook and Instagram.  

Reducing reliance on resupply missions

Resupply of life support elements such as air, water, food, clothing, and hygiene items will be impractical on missions to the Moon and beyond. This research assessed current use and resupply of these elements on the International Space Station and outlines technologies needed for sustained human presence in space, such as 3D printing maintenance parts, systems for laundering clothes, and improved recovery and recycling of elements.

Researchers analyzed the types and mass of elements supplied from Earth to the station and astronaut feedback from various studies and interviews. The paper also used data from ISS Internal Environments, a wide-ranging investigation that samples various aspects of the space station environment in support of many types of research.

Verifying a technique for analyzing emulsions

This paper presents a review of examining the behavior of emulsions (suspensions of particles in a liquid) in microgravity using a technique called diffusing wave spectroscopy. Results offer insights that could support development of technologies to improve living environments and foods for crew members on future missions.

FSL Soft Matter Dynamics – PASTA studied the dynamics of droplets in emulsions. Accurate study and characterization of the effects of additives on emulsion stability is possible in microgravity. Emulsions have applications in foods, cosmetics, pharmaceuticals, fuels, paints and coatings, chemical processing, and materials.

EEG measurements and predicting cognitive changes in spaceflight

Researchers used an electroencephalogram (EEG) to measure brainwave activity during a relaxed, wakeful state in crew members and found no significant differences before, during, and after flight. These types of measurements could serve as biomarkers of brain health status, helping to predict changes in cognitive performance and the need for prevention and countermeasure strategies during future missions.

Studies have shown that spaceflight can affect key cognitive and motor skills such as task management, attention, and movement speed and accuracy. Neurowellness in Space Ax-1 tested using a portable, easy to use EEG headset to measure ongoing and task-related brain activity in microgravity. The data could help predict and monitor neural changes on future space missions.

NASA will brief media at 11 a.m. EST Wednesday, Jan. 29, to provide an update on science results from NASA’s OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security – Regolith Explorer) mission, which delivered a sample of asteroid Bennu to Earth in September 2023.

Audio of the media call will stream live on the agency’s website.

Participants in the teleconference include:

• Nicky Fox, associate administrator, Science Mission Directorate, NASA Headquarters, Washington
• Danny Glavin, senior scientist for sample return, NASA’s Goddard Space Flight Center Greenbelt, Maryland
• Jason Dworkin, OSIRIS-REx project scientist, NASA Goddard
• Tim McCoy, curator of meteorites, Smithsonian Natural History Museum, Washington 
• Sara Russell, cosmic mineralogist, Natural History Museum, London

Media interested in participating by phone must RSVP no later than two hours prior to the start of the call to: molly.l.wasser@nasa.gov. A copy of NASA’s media accreditation policy is online.

After the teleconference, NASA Goddard will host a limited onsite media availability for reporters local to the greater Washington area. The availability will include opportunities to tour the center’s astrobiology lab, which contributed to the study of the Bennu sample. Interested reporters should request participation by Sunday, Jan. 26, to: rob.garner@nasa.gov.

Launched on Sept. 8, 2016, OSIRIS-REx was the first U.S. mission to collect a sample from an asteroid in space. The spacecraft traveled to near-Earth asteroid Bennu and collected a sample of rocks and dust from the surface in 2020. It delivered the sample to Earth on Sept. 24, 2023.

To learn more about OSIRIS-REx, visit:

https://science.nasa.gov/mission/osiris-rex/

-end-

Karen Fox / Molly Wasser
Headquarters, Washington
202-358-1600
karen.c.fox@nasa.gov / molly.l.wasser@nasa.gov

On Jan. 24, 1985, space shuttle Discovery took off from NASA’s Kennedy Space Center (KSC) in Florida on STS-51C, the first space shuttle mission entirely dedicated to the Department of Defense (DOD). As such, many of the details of the flight remain classified. Discovery’s crew of Commander Thomas “T.K.” Mattingly, Pilot Loren Shriver, Mission Specialists Ellison Onizuka and James Buchli, and Payload Specialist Gary Payton deployed a classified satellite that used an Inertial Upper Stage (IUS) to reach its final geostationary orbit. The three-day mission ended with a landing at KSC. Postflight inspection of the Solid Rocket Boosters (SRBs) revealed the most significant erosion of O-ring seals seen in the shuttle program up to that time, attributed to unusually cold weather before and during launch. 

In October 1982, NASA assigned astronauts Mattingly, Shriver, Onizuka, and Buchli as the STS-10 crew for a dedicated DOD flight aboard Challenger then scheduled for September 1983. Payton joined the crew as a payload specialist in the summer of 1983 with Keith Wright assigned as his backup. The failure of the IUS on STS-6 in April 1983 delayed the STS-10 mission, that also used the IUS, until engineers could identify and fix the cause of the problem. By September 1983, NASA had remanifested the crew and the payload on STS-41F with a July 1984 launch, that changed to STS-41E by November 1983. Additional delays in fixing the IUS delayed the mission yet again, by June 1984 redesignated as STS-51C and slated for December 1984 aboard Challenger. 

STS-51C marked the third spaceflight for Mattingly, selected in 1966 as part of NASA’s fifth group of astronauts. He served on the prime crew for Apollo 13 until exposure to German measles forced his last-minute replacement by his backup. He then flew on Apollo 16 and STS-4. For Shriver, Onizuka, and Buchli, all three selected as astronauts in the class of 1978, STS-51C marked their first trip into space. The U.S. Air Force selected Payton and Wright in August 1979 in its first class of Manned Spaceflight Engineers, and STS-51C marked Payton’s first and only space mission. 

In November 1984, NASA decided to delay STS-51C from December 1984 to January 1985 and swap orbiters from Challenger to Discovery. Postflight inspections following Challenger’s STS-41G mission in October 1984 revealed degradation of the bonding materials holding thermal protection system tiles onto the orbiter, requiring the replacement of 4,000 tiles. The time required to complete the work precluded a December launch. Tests conducted on Discovery prior to its November STS-51A mission revealed the bonding material to be sound.  

On Jan. 5, 1985, Discovery rolled out from KSC’s Vehicle Assembly Building, where workers mated it with its External Tank (ET) and SRBs, to Launch Pad 39A. There, engineers conducted the Terminal Countdown Demonstration Test, essentially a dress rehearsal for the actual countdown, on Jan. 6-7, with the crew participating in the final few hours much as they would on launch day. The astronauts returned to KSC on Jan. 20 to prepare for the planned launch on Jan. 23. The day before, NASA managers decided to delay the launch by one day due to unseasonably cold weather, with concern about sub-freezing temperatures causing ice to form on the ET and possibly coming loose during ascent and damaging the vehicle. The DOD had requested that NASA keep the actual launch time secret until T minus nine minutes, with most of the countdown taking place hidden from public view.  

Liftoff of Discovery on its third mission, STS-51C, came at 2:50 p.m. EST on Jan. 24, beginning the 15^th space shuttle flight. Eight and a half minutes later, Discovery and its five-man crew had reached orbit. And, at the DOD customer’s request, all public coverage of the mission ended. Although NASA could not reveal the spacecraft’s orbital parameters, trade publications calculated that Discovery first entered an elliptical orbit, circularized over the next few revolutions, prior to Onizuka deploying the IUS and payload combination on the seventh orbit. Neither NASA nor the DOD have released any imagery of the deployment or even of the payload bay, with only a limited number of in-cabin and Earth observation photographs made public. 

To maintain the mission’s secrecy, NASA could reveal the touchdown time only 16 hours prior to the event. On Jan. 27, Mattingly and Shriver brought Discovery to a smooth landing at KSC’s Shuttle Landing Facility after a flight of three days one hour 33 minutes, the shortest space shuttle mission except for the first two orbital test flights. The astronauts orbited the Earth 49 times. About an hour after touchdown, the astronaut crew exited Discovery and boarded the Astrovan for the ride back to crew quarters. Neither NASA management nor the astronauts held a post mission press conference. The U.S. Air Force announced only that the “IUS aboard STS-51C was deployed from the shuttle Discovery and successfully met its mission objectives.” Later in the day, ground crews towed Discovery to the Orbiter Processing Facility to begin preparing it for its next planned mission, STS-51D in March. 

Postscript 

Following the recovery of SRBs after each shuttle mission, engineers conducted detailed inspections before clearing them for reuse. After STS-51C, inspections of the critical O-ring seals that prevented hot gases from escaping from the SRB field joints revealed significant erosion and “blow-by” between the primary and secondary O-rings. Both left and right hand SRBs showed this erosion, the most significant of the program up to that time. Importantly, these O-rings experienced weather colder than any previous shuttle mission, with overnight ambient temperatures in the teens and twenties. Even at launch time, the O-rings had reached only 60 degrees. Engineers believed that these cold temperatures made the O-rings brittle and more susceptible to erosion. One year later, space shuttle Challenger launched after similarly cold overnight temperatures, with O-rings at 57 degrees at launch time. The Rogers Commission report laid the blame of the STS-51L accident on the failure of O-rings that allowed super-hot gases to escape from the SRB and impinge on the hydrogen tank in the ET, resulting in the explosion that destroyed the orbiter and claimed the lives of seven astronauts. The commission also faulted NASA’s safety culture for not adequately addressing the issue of O-ring erosion, a phenomenon first observed on STS-2 and to varying degrees on several subsequent missions.  

Insights into metal alloy solidification

Researchers report details of phase and structure in the solidification of metal alloys on the International Space Station, including formation of microstructures. Because these microstructures determine a material’s mechanical properties, this work could support improvements in techniques for producing coatings and additive manufacturing or 3D printing processes.

METCOMP, an ESA (European Space Agency) investigation, studied solidification in microgravity using transparent organic mixtures as stand-ins for metal alloys. Conducting the research in microgravity removed the influence of convection and other effects of gravity. Results help scientists better understand and validate models of solidification mechanisms, enabling better forecasting of microstructures and improving manufacturing processes.

Measuring the height of upper-atmospheric electrical discharges

Researchers determined the height of a blue discharge from a thundercloud using ground-based electric field measurements and space-based optical measurements from Atmosphere-Space Interactions Monitor (ASIM). This finding helps scientists better understand how these high-altitude lightning-related events affect atmospheric chemistry and could help improve atmospheric models and climate and weather predictions.

ESA’s ASIM is an Earth observation facility that studies severe thunderstorms and upper-atmospheric lighting events and their role in the Earth’s atmosphere and climate. Upper-atmospheric lightning, also known as transient luminous events, occurs well above the altitudes of normal lightning and storm clouds. The data collected by ASIM could support research on the statistical properties of many upper atmosphere lightning events, such as comparison of peak intensities of blue and red pulses with reports from lightning detection networks.

Modeling a complex neutron star

Scientists report that they can use modeling of neutron star PSRJ1231−1411’s X-ray pulses to infer its mass and radius and narrow the possible behaviors of the dense matter at its core. This finding provides a better understanding of the composition and structure of these celestial objects, improving models that help answer questions about conditions in the universe.

The Neutron star Interior Composition Explorer provides high-precision measurements of pulses of X-ray radiation from neutron stars. This particular neutron star presented challenges in finding a fit between models and data, possibly due to fundamental issues with its pulse profile. The authors recommend a program of simulations using synthetic data to determine whether there are fundamental issues with this type of pulse profile that could prevent efforts to obtain tighter and more robust constraints.

On Jan. 17, 1990, NASA announced the selection of its 13^th group of astronaut candidates. The diverse group comprised 23 candidates – seven pilots and 16 mission specialists. The group included one African American, one Asian American, and five women including the first female pilot and the first Hispanic woman. Following one year of astronaut candidate training, all 23 became eligible for technical assignments within the astronaut office and for assignment to space shuttle crews. All members of the group completed at least one spaceflight, making significant contributions to the space shuttle program, the Shuttle Mir program, important science missions, and assembly and maintenance of the International Space Station. Several went on to serve in key NASA management positions. 

The newest class of NASA astronaut candidates included pilot candidates Kenneth Cockrell, Eileen Collins, William Gregory, James Halsell, Charles Precourt, Richard Searfoss, and Terrence Wilcutt and mission specialist candidates Daniel Bursch, Leroy Chiao, Rich Clifford, Bernard Harris, Susan Helms, Thomas Jones, William Mc Arthur, James Newman, Ellen Ochoa, Ronald Sega, Nancy Sherlock, Donald Thomas, Janice Voss, Carl Walz, Jeffrey Wisoff, and David Wolf. From the 1,945 qualified applicants, NASA invited 103 candidates for interviews and medical exams at NASA’s Johnson Space Center (JSC) in Houston between September and November 1989. 

The 23 astronaut candidates reported to work at JSC on July 16, 1990, to begin their one-year training period. During the yearlong training, the candidates attended classes in applied sciences, space shuttle systems, space medicine, Earth and planetary sciences, and materials sciences. They visited each of the NASA centers to learn about their functions and received instruction in flying the T-38 Talon training aircraft, high-altitude and ground egress systems, survival skills, parasail flight, and scuba. They experienced short-duration weightlessness aboard NASA’s KC-135 aircraft dubbed the Vomit Comet. After completing the astronaut candidate training, they qualified for various technical assignments within the astronaut office leading to assignments to space shuttle crews. 

Per tradition, most astronaut classes have a nickname, often humorously given to them by the previous class of astronauts. In the case of the class of 1990, they chose their own nickname, The Hairballs. The origin stems from the class adopting a black cat as their mascot, in recognition of their class number 13. The nickname came about as hairballs are often associated with cats. 

Daniel Bursch 

Born in Pennsylvania, Bursch grew up in New York state and graduated from the U.S. Naval Academy. He served as a pilot in the U.S. Navy prior to his selection as an astronaut. He received his first flight assignment as a mission specialist on STS-51, flying with fellow Hairballs Newman and Walz on the 10-day flight aboard Discovery in 1993. On his second mission, the 10-day STS-68 flight aboard Endeavour in 1994, Bursch, accompanied by fellow classmates Jones, Wilcutt, and Wisoff, served as a mission specialist on the Space Radar Laboratory-2 (SRL-2) Earth observation mission. For his third trip into space, Bursch flew as a mission specialist aboard Endeavour for the 10-day STS-77 mission in 1996. For his fourth and final spaceflight, Bursch, along with fellow Hairball Walz, spent 196 days in space as an Expedition 4 flight engineer aboard the space station in 2001 and 2002, conducting two spacewalks totaling 11 hours 46 minutes. He launched on STS-108 and returned on STS-111. Across his four missions, Bursch accumulated 227 days in space. 

Leroy Chiao 

California native Chiao earned a doctorate in chemical engineering from the University of California, Santa Barbara, before NASA selected him as an astronaut. For his first flight, he flew as a mission specialist on STS-65, the International Microgravity Lab-2 (IML-2) mission aboard Columbia in 1994. Fellow Hairballs Halsell, Walz, and Thomas accompanied Chiao on the nearly 15-day flight, the longest shuttle mission up to that time. During his second spaceflight, the nine-day STS-72 flight of Endeavour in 1996, Chiao participated in two spacewalks totaling 13 hours 3 minutes to demonstrate future techniques. In 2000, Chiao, accompanied by fellow classmates McArthur and Wisoff, flew the 13-day STS-92 3A space station assembly mission aboard Discovery. He participated in two spacewalks with classmate McArthur totaling 13 hours 16 minutes. For his fourth and final mission, Chiao served as commander of Expedition 10 in 2004 and 2005, spending 193 days in space. During the mission, he conducted two spacewalks totaling 9 hours 58 minutes. During his four flights, Chiao logged 229 days in space and spent more than 36 hours outside on his six spacewalks. 

Rich Clifford 

Clifford, born in California, grew up in Ogden, Utah. He holds the distinction as one of the first three astronauts of his class assigned to a spaceflight, the seven-day STS-53 mission aboard Discovery in 1992 to deploy a large satellite for the Department of Defense. His second flight, the SRL-1 mission aboard Endeavour took place in 1994. Fellow Hairball Jones accompanied him on the STS-59 11-day Earth observation mission. For his third and final spaceflight, Clifford flew as a mission specialist on the STS-76 third Shuttle Mir docking mission. During the nine-day mission in 1996, accompanied by fellow classmate Sega, Clifford participated in a six-hour one-minute spacewalk. During his three spaceflights, he accumulated nearly 28 days in space. 

Kenneth Cockrell 

Cockrell, a native Texan, served as naval aviator prior to his selection as an astronaut. On his first mission, STS-56, he served as a mission specialist for the nine-day ATLAS-2 Earth observation mission in 1993. Fellow classmate Ochoa accompanied him on the flight aboard Discovery. Cockrell served as pilot on his second mission, the 11-day STS-69 Endeavour flight in 1995 to deploy and retrieve the Wake Shield Facility. Classmate Voss accompanied him on this mission. Cockrell commanded his third spaceflight, STS-80 in 1996 aboard Columbia, accompanied by fellow Hairball Jones. At 17 days 15 hours 53 minutes days, it holds the distinction as the longest shuttle flight. He once again served as commander on his fourth mission, the STS-98 5A space station assembly flight in 2001. Accompanied by classmate Jones, the crew delivered the U.S. Laboratory Module Destiny during the 13-day mission. On his fifth and final spaceflight, Cockrell commanded the STS-111 space station UF-2 utilization mission in 2002. During the 14-day flight, the crew brought the Expedition 5 crew to the station and returned the Expedition 4 crew, including Hairballs Bursch and Walz. During his five missions, Cockrell accumulated 64.5 days in space. He served as Chief of the Astronaut Office from October 1997 to October 1998. 

Eileen Collins 

Hailing from New York state, Collins has the distinction as the first female selected by NASA as a shuttle pilot. She received her first flight assignment as pilot of STS-63, the eight-day Shuttle-Mir rendezvous mission in 1995. Fellow classmates Harris and Voss accompanied her aboard Discovery. Collins once again served as pilot on STS-84, the sixth Shuttle-Mir docking mission commanded by fellow Hairball Precourt. The nine-day flight aboard Atlantis took place in 1997. On her third flight, Collins served as the first female commander of a space mission, the five-day STS-93 flight of Columbia in 1999 to deploy the Chandra X-ray Observatory. She commanded her fourth and final mission, the STS-114 return to flight mission following the Columbia accident. The 14-day flight aboard Discovery took place in 2005. During her four missions, Collins logged 36 days in space. 

William Gregory 

New York native Gregory served as a U.S. Air Force pilot when NASA selected him as an astronaut. He flew his single mission as pilot of STS-67, the 17-day Astro-2 mission aboard Endeavour in 1995. The mission set a record for the longest shuttle flight up to that time. 

James Halsell 

Halsell, a native of Louisiana, served as a U.S. Air Force pilot when NASA selected him as an astronaut. On his first spaceflight, he served as pilot on STS-65, the IML-2 mission aboard Columbia in 1994. Fellow Hairballs Chiao, Walz, and Thomas accompanied Halsell on the nearly 15-day flight, the longest shuttle mission up to that time. Halsell once again served as pilot on his second flight, STS-74, the second Shuttle-Mir docking mission that delivered the Docking Module to Mir. Classmate McArthur joined Halsell on the eight-day Atlantis flight in 1995. He commanded his third spaceflight, STS-83 aboard Columbia, the Microgravity Sciences Lab in 1997. Because managers cut the flight short after four days due to a fuel cell failure, NASA decided to refly the mission, with the same crew, later in the year as STS-94, and it stayed in space for nearly 16 days. Classmates Voss and Thomas accompanied Halsell on both missions. Halsell also commanded his fifth and final spaceflight, the STS-101 2A.2a space station logistics mission in 2000. Classmate Helms accompanied Halsell on the 10-day mission aboard Atlantis. During his five missions, Halsell accumulated more than 52 days of spaceflight time.  

Bernard Harris 

Texas native Harris served as a NASA flight surgeon when the agency selected him as an astronaut. He holds the distinction as one of the first three astronauts of his class assigned to a spaceflight. He served as a mission specialist on the STS-55 joint U.S.-German Spacelab D2 mission in 1993. Fellow Hairball Precourt accompanied him on the 10-day flight aboard Columbia. Harris flew as payload commander on his second and final spaceflight, the STS-63 Mir rendezvous mission in 1995, accompanied by classmates Collins and Voss. During the flight, Harris conducted a 4-hour 49-minute spacewalk, earning the distinction as the first African American to do so. Across his two missions, Harris logged 18 days in space. 

Susan Helms 

Helms, a native of Portland, Oregon, graduated from the U.S. Air Force Academy in the first class that included women. Shortly after her selection as an astronaut, NASA assigned her to her first spaceflight, and she holds the distinction as one of the first three astronauts of her class assigned to a mission. She flew as a mission specialist on STS-54, a six-day flight aboard Endeavour in 1993 that deployed the sixth Tracking and Data Relay Satellite. On her second mission, Helms flew aboard STS-64, an 11-day flight aboard Discovery in 1994. She served as the payload commander on STS-78, the Life and Microgravity Sciences Spacelab mission aboard Columbia in 1996. The flight set a then-record of 16 days 22 hours for the longest space shuttle mission. On her fourth mission, she served as a mission specialist on STS-101, the 2A.2a space station logistics mission in 2000 commanded by classmate Halsell. The Atlantis mission lasted 10 days. For her fifth and final spaceflight, she served as a flight engineer during Expedition 2, the first woman to fly a long-duration mission on the International Space Station. She conducted one spacewalk lasting 8 hours 56 minutes, a record not broken until 2024. During her five spaceflights she logged 211 days in space. 

Thomas Jones 

Jones, a native of Baltimore, graduated from the U.S. Air Force Academy and served as a B-52 pilot when NASA selected him as an astronaut. For his first spaceflight, he served as a mission specialist on STS-59, the 11-day SRL-1 Earth observation mission on Endeavour in 1994, along with classmate Clifford. Later that same year, with just 163 days between the two missions – the second shortest turnaround time in history – Jones served as payload commander on STS-68, the 11-day SRL-2 mission also on Endeavour. Fellow Hairballs Wilcutt, Wisoff, and Bursch accompanied him on the mission. In 1996, Jones flew as a mission specialist on STS-80, commanded by classmate Cockrell. During the nearly 18-day flight – the longest shuttle flight in history – Jones had planned to participate in two spacewalks, but a stuck bolt prevented the opening of Columbia’s airlock hatch, forcing the cancelation of the excursions. Jones flew his fourth and final mission in 2001, the STS-98 5A space station assembly flight, commanded by classmate Cockrell. During the 13-day mission of Atlantis, the crew installed the U.S. Laboratory Module Destiny and Jones participated in three spacewalks totaling nearly 20 hours. During his four spaceflights, Jones logged 53 days in space. 

William McArthur 

Hailing from North Carolina, West Point graduate McArthur worked as a space shuttle vehicle integration test engineer at JSC when NASA selected him as an astronaut. He received his first spaceflight assignment as a mission specialist on the STS-58 Spacelab Life Sciences-2 (SLS-2) mission in 1993. Classmates Searfoss and Wolf accompanied him on the 14-day Columbia mission, at the time the longest space shuttle flight. In 1995, he flew as a mission specialist on STS-74, the second Shuttle Mir docking mission that brought the Docking Module to Mir. Classmate Halsell served as pilot on the eight-day flight of Atlantis. McArthur next flew on STS-92, the 3A space station assembly mission in 2000, accompanied by classmates Chiao and Wisoff. McArthur completed two spacewalks with Chiao totaling 13 hours 16 minutes during the 13-day Atlantis mission. For his fourth and final spaceflight, McArthur served as commander of the 190-day Expedition 12 in 2005-2006, conducting two spacewalks totaling 11 hours 5 minutes. During his four missions, McArthur logged 225 days in space and spent more than 24 hours on four spacewalks. He served as the director of the JSC Safety and Mission Assurance Directorate from 2011 to 2017. 

James Newman 

Born in Micronesia, Newman grew up in San Diego and earned a doctorate in physics from Rice University. He worked at JSC as a crew and flight controller trainer when NASA selected him as an astronaut. For his first spaceflight assignment, Newman flew as a mission specialist on STS-51 in 1993 with fellow Hairballs Bursch and Walz. During the 10-day mission aboard Discovery, Newman conducted a 7-hour 5-minute spacewalk with Walz to demonstrate future spacewalking techniques. His second flight took place in 1995, the 11-day STS-69 mission of Endeavour, with classmate Halsell serving as pilot. On his third mission, Newman flew as a mission specialist on STS-88, the first space station assembly flight in 1998. Classmate Sherlock, now using her married name Currie, accompanied him on the 12-day Atlantis mission. Newman participated in three spacewalks totaling 21 hours 22 minutes. For his fourth and final spaceflight in 2002, Newman flew on STS-109, the fourth servicing mission to the Hubble Space Telescope, accompanied once again by classmate Currie. During the 11-day Columbia mission, Newman conducted two spacewalks totaling 14 hours 46 minutes. During his career four spaceflights, Newman logged more than 43 days in space and spent nearly 50 hours on six spacewalks. 

Ellen Ochoa 

Born in Los Angeles, Ochoa received her doctorate in electrical engineering from Stanford University and worked at NASA’s Ames Research Center in California’s Silicon Valley when NASA selected her as an astronaut. Her first flight assignment came in 1993 when she flew as a mission specialist on STS-56, the nine-day ATLAS-2 Earth observation mission. Classmate Cockrell accompanied her on the Discovery mission. On her second spaceflight, she served as payload commander on the STS-66 ATLAS-3 mission, an 11-day flight of Atlantis in 1994. For her third flight, she flew on Discovery’s STS-96, the 10-day 2A.1 space station assembly and logistics mission in 1999. In 2002, on her fourth and final mission, STS-110, she served as a mission specialist on the 8A space station assembly flight that brought the S0 truss to the facility. The flight on Atlantis lasted nearly 11 days. Over her four missions, Ochoa accumulated nearly 41 days in space. Following her spaceflights, Ochoa served in management positions with increasing scope and responsibilities, as director of the Flight Crew Operations Directorate, JSC deputy director, and JSC director. 

Charles Precourt 

Massachusetts native Precourt graduated from the U.S. Air Force Academy and served as a U.S. Air Force pilot when NASA selected him as an astronaut. On his first spaceflight in 1993, he served as a mission specialist on STS-55, the joint U.S.-German Spacelab D2 mission. Fellow Hairball Harris accompanied him on the 10-day Columbia mission. On his next spaceflight, Precourt served as pilot on STS-71, the first Shuttle-Mir docking mission in 1995. The 10-day Atlantis mission included the first shuttle-based crew rotation. Precourt commanded his third spaceflight, STS-84 in 1987, the sixth Shuttle-Mir docking mission. Classmate Collins served as pilot on the nine-day Atlantis mission. He commanded his fourth and final space mission, STS-91, the ninth and final Shuttle-Mir docking flight, earning him the honor as the only American astronaut to visit Mir three times. The 10-day mission aboard Discovery took place in 1998. Across his four spaceflights, Precourt logged nearly 39 days in space. He served as chief of the Astronaut Office from October 1998 to November 2002. 

Richard Searfoss 

Born in Michigan, Searfoss graduated from the U.S. Air Force Academy and served as an instructor at the U.S. Air Force Test Pilot School when NASA selected him as an astronaut. On his first spaceflight, Searfoss served as pilot on STS-58, the SLS-2 mission in 1993. Classmates McArthur and Wolf joined him on the flight aboard Columbia, at 14 days then the longest space shuttle mission. In 1996, he once again served as pilot on STS-76, the third Shuttle-Mir docking mission. Classmates Clifford and Sega joined him on the nine-day flight aboard Atlantis. Searfoss commanded his third and final spaceflight, the 16-day STS-90 Neurolab mission aboard Columbia in 1998. Across his three missions, Searfoss logged 39 days in space. 

Ronald Sega 

Ohio native Sega graduated from the U.S. Air Force Academy and worked as a research associate professor of physics at the University of Houston when NASA selected him as an astronaut. On his first spaceflight, he served as a mission specialist aboard STS-60, the first Shuttle-Mir mission. The eight-day mission aboard Discovery took place in 1994. For his second and final spaceflight in 1996, Sega served as a mission specialist on STS-76, the third Shuttle-Mir docking mission. Fellow Hairballs Searfoss and Clifford also flew on the nine-day Atlantis mission. Across his two spaceflights, Sega logged 17.5 days in space. 

Nancy Sherlock Currie 

Born in Delaware, Sherlock grew up in Ohio and worked as a flight simulation engineer at JSC when NASA selected her as an astronaut. On her debut spaceflight, Sherlock flew as a mission specialist on STS-57, the first flight of the Spacehab module in 1993. Fellow classmates Voss and Wisoff joined her on the 10-day mission aboard Endeavour. On her subsequent missions, she flew under her married name of Currie. Her second trip into space took place in 1995, the nine-day STS-70 mission aboard Discovery. Classmate Thomas joined her on this mission to deploy the seventh TDRS satellite. On her third mission, Currie flew as a mission specialist on STS-88, the first space station assembly mission in 1998. Classmate Newman accompanied her on the 12-day Atlantis mission. For her fourth and final spaceflight in 2002, Currie flew on STS-109, the fourth Hubble Space Telescope servicing mission. Classmate Newman once again accompanied her on the 11-day Columbia mission. Across her four spaceflights, Currie logged nearly 42 days in space. 

Donald Thomas 

Ohio native Thomas earned a doctorate in materials science from Cornell University and worked as a materials science engineer at JSC when NASA selected him as an astronaut. For his first flight, he flew as a mission specialist on STS-65, the IML-2 mission aboard Columbia in 1994. Fellow Hairballs Halsell, Chiao, and Walz accompanied Thomas on the nearly 15-day flight, the longest shuttle mission up to that time. His second trip into space took place in 1995, the nine-day STS-70 mission aboard Discovery. Classmate Currie joined him on this mission to deploy the seventh TDRS satellite. Thomas flew his third spaceflight on STS-83 aboard Columbia, the MSL mission in 1997. Because managers cut the flight short after four days due to a fuel cell failure, NASA decided to fly the mission again, with the same crew, later in the year as STS-94, for the full 16-day mission duration. Classmates Halsell and Voss accompanied Thomas on both missions. Across his four missions, Thomas logged 43 days in space. 

Janice Voss 

Ohio native Voss earned a doctorate in aeronautics and astronautics from the Massachusetts Institute of Technology and worked as an integration manager at Orbital Science Corporation in Houston when NASA selected her as an astronaut. On her first spaceflight, Voss flew as a mission specialist on STS-57, the first flight of the Spacehab module in 1993. Fellow classmates Sherlock and Wisoff joined her on the 10-day mission aboard Endeavour. Voss flew as a mission specialist on her second spaceflight, the STS-63 Mir rendezvous mission in 1995, accompanied by classmates Collins and Harris. Voss flew as payload commander on her third spaceflight on STS-83 aboard Columbia, the MSL mission in 1997. Because managers cut the flight short after four days due to a fuel cell failure, NASA decided to refly the mission, with the same crew, later in the year as STS-94, for the full 16-day mission duration. Classmates Halsell and Thomas accompanied Voss on both missions. On her fifth and final spaceflight, Voss once again served as payload commander on STS-99, the Shuttle Radar Topography Mission. The 11-day mission aboard Endeavour took place in 2000. Over her five missions, Voss accumulated 49 days of spaceflight time. 

Carl Walz 

A native of Ohio, Walz worked as a flight test manager at the U.S. Air Force Flight Test Center in Nevada when NASA selected him as an astronaut. He received his first flight assignment as a mission specialist on STS-51, flying with fellow Hairballs Bursch and Newman on the 10-day flight aboard Discovery in 1993. Walz conducted a 7-hour 5-minute spacewalk with Newman to demonstrate future spacewalking techniques. For his second flight, he flew as a mission specialist on STS-65, the IML-2 mission aboard Columbia in 1994. Fellow Hairballs Halsell, Chiao, and Thomas accompanied Walz on the nearly 15-day flight, the longest shuttle mission up to that time. On his third trip into space, he served as a mission specialist on STS-79, the fourth Shuttle-Mir docking mission in 1996. Classmate Wilcutt served as pilot on the 10-day Atlantis mission. For his fourth and final spaceflight, Walz, along with fellow Hairball Bursch, spent 196 days in space as an Expedition 4 flight engineer aboard the space station in 2001 and 2002, conducting two spacewalks totaling 11 hours 50 minutes. He launched on STS-108 and returned on STS-111. Across his four missions, Walz logged more than 230 days in space and spent nearly 19 hours on three spacewalks. 

Terrance Wilcutt 

A native of Kentucky, Wilcutt served in the U.S. Marine Corps and worked as a test pilot at Naval Air Station Patuxent River when NASA selected him as an astronaut. Wilcutt served as pilot on his first spaceflight, STS-68, the 10-day SRL-2 Earth observation mission aboard Endeavour in 1994. Classmates Bursch, Jones, and Wisoff accompanied Wilcutt on the flight. He served as pilot on his second spaceflight, the STS-79 fourth Shuttle-Mir docking mission in 1996. Fellow Hairball Walz accompanied him on the 10-day Atlantis mission. Wilcutt commanded his third mission, STS-89, the eighth Shuttle-Mir docking mission. The nine-day flight aboard Endeavour took place in 1998. He commanded his fourth and final spaceflight in 2000, the STS-106 2A.2b space station assembly and logistics mission. The 12-day mission flew on Atlantis. Across his four missions, Wilcutt logged 42 days in space. He served as the NASA chief of Safety and Mission Assurance from 2011 to 2020. 

Jeff Wisoff 

Virginia native Wisoff earned a doctorate in applied physics from Stanford University and worked as an assistant professor at Rice University when NASA selected him as an astronaut. On his first spaceflight, Wisoff flew as a mission specialist on STS-57, the first flight of the Spacehab module in 1993. Fellow classmates Sherlock and Voss joined him on the 10-day mission aboard Endeavour. He participated in a 5-hour 50-minute spacewalk to demonstrate future spacewalking techniques. Wisoff served as a mission specialist on his second spaceflight, STS-68, the 10-day SRL-2 Earth observation mission aboard Endeavour in 1994. Classmates Bursch, Jones, and Wilcutt accompanied him on the flight. He served as a mission specialist on his third flight, STS-81, the fifth Shuttle-Mir docking mission in 1997. The 10-day flight took place aboard Atlantis. He flew his fourth and final mission on STS-92, the 3A space station assembly mission in 2000 that brought the Z1 truss to the facility. Wisoff participated in two spacewalks totaling 14 hours 3 minutes during the 13-day Discovery mission. Across his four spaceflights, Wisoff logged 44 days in space and spent nearly 20 hours on three spacewalks. 

David Wolf 

A native of Indiana, Wolf earned a medical degree from Indiana University and worked as an aerospace medical officer at JSC when NASA selected him as an astronaut. He received his first spaceflight assignment as a mission specialist on the STS-58 SLS-2 mission in 1993. Classmates Searfoss and McArthur accompanied him on the 14-day Columbia mission, at the time the longest space shuttle flight. For his second trip into space, he completed the 128-day NASA-6 long-duration mission as part of the Shuttle-Mir program in 1997 and 1998, launching aboard STS-86 and returning aboard STS-89. He participated in a 3-hour 52-minute spacewalk. He flew his third spaceflight as a mission specialist on the STS-112 9A space station assembly mission in 2002 that delivered the S1 truss to the orbiting lab. During the 11-day Atlantis mission, Wolf participated in three spacewalks totaling 19 hours 41 minutes. He completed his fourth mission on STS-127 in 2009, earning him the distinction as the last Hairball to make a spaceflight. During the 16-day Endeavour mission that delivered the Japanese module’s exposed pallet to the space station, Wolf participated in three spacewalks totaling 18 hours 24 minutes. Across his four spaceflights, Wolf logged more than 168 days in space and spent 42 hours on seven spacewalks. 

Summary

The NASA Group 13 astronauts made significant contributions to spaceflight. As a group, they completed 85 flights spending 1,960 days, or more than five years, in space, including one long-duration flight aboard Mir and five aboard the International Space Station. One Hairball made a single trip into space, three made two trips, one made three, 15 made four, and three went five times. Twenty-one members of the group contributed their talents on Spacelab or other research missions and three performed work with the great observatories Hubble and Chandra. Thirteen participated in the Shuttle Mir program, with 11 visiting the orbiting facility, one of them twice, another three times, and one completing a long-duration mission. Fifteen visited the International Space Station, five twice, participating in its assembly, research, maintenance, and logistics, with five completing long-duration missions aboard the facility. Eleven of the 23 performed 37 spacewalks spending 242 hours, or more than 10 days, outside their spacecraft.