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By NASA
“Trying to do stellar observations from Earth is like trying to do birdwatching from the bottom of a lake.” James B. Odom, Hubble Program Manager 1983-1990.
The third servicing mission to the Hubble Space Telescope, placed in orbit in 1990, occurred during the STS-103 mission in December 1999. During the mission, originally planned for June 2000 but accelerated by six months following unexpected failures of the telescope’s attitude control gyroscopes, the astronauts restored the facility to full functionality. During their eight-day mission that featured the first space shuttle crew to spend Christmas in space, the seven-member U.S. and European crew rendezvoused with and captured Hubble, and four astronauts in rotating teams of two conducted three lengthy and complex spacewalks to service and upgrade the telescope. They redeployed the telescope with greater capabilities than ever before to continue its mission to help scientists unlock the secrets of the universe.
Schematic showing the Hubble Space Telescope’s major components. Workers inspect the Hubble Space Telescope’s 94-inch diameter primary mirror prior to assembly. Astronauts release the Hubble Space Telescope in April 1990 during the STS-31 mission. The discovery after the Hubble Space Telescope’s launch in 1990 that its primary mirror suffered from a flaw called spherical aberration disappointed scientists who could not obtain the sharp images they had expected. But thanks to the Hubble’s built-in feature of on-orbit servicing, NASA devised a plan to correct the telescope’s optics during the first planned repair mission in 1993. A second servicing mission in 1997 upgraded the telescope’s capabilities until the next mission planned for three years later. But after three of the telescope’s six gyroscopes failed in 1997, 1998, and 1999, mission rules dictated a call up mission in case additional gyroscope failures sent Hubble into a safe mode. NASA elected to move up some of the servicing tasks from the third mission, splitting it into missions 3A and 3B, planning to fly 3A in October 1999 on Discovery’s STS-103 mission primarily to replace the failed gyroscopes. Delays to the shuttle fleet resulting from anomalies during the launch of STS-93 in July 1993 slipped STS-103 first into November and ultimately into December. Technical issues with Discovery itself pushed the launch date to mid-December, and raised concerns about having a shuttle in orbit during the Y2K transition. Once the launch had slipped to Dec. 19, mission planners cut the mission from 10 to eight days, deleting one of the four spacewalks, to ensure a return before the end of the calendar year. The servicing mission couldn’t come soon enough, as a fourth gyroscope failed aboard Hubble in mid-November, with Discovery already poised on the launch pad to prepare for STS-103. Controllers placed Hubble in a safe mode until the astronauts arrived.
The STS-103 crew of C. Michael Foale, left, Claude Nicollier, Scott J. Kelly, Curtis L. Brown, Jean-François A. Clervoy, John M. Grunsfeld, and Steven L. Smith. The STS-103 crew patch. The mission patch for the Hubble Servicing Mission-3A. To execute the third Hubble Servicing Mission, in July 1998 NASA selected an experienced four-person team to carry out a record-breaking six spacewalks on the flight then planned for June 2000. The spacewalkers included Mission Specialists Steven L. Smith serving as payload commander, John M. Grunsfeld, C. Michael Foale, and European Space Agency (ESA) astronaut Claude Nicollier from Switzerland. The addition in March 1999 of Commander Curtis L. Brown, Pilot Scott J. Kelly, and Mission Specialist ESA astronaut Jean-François A. Clervoy of France rounded out the highly experienced crew with 18 previous spaceflights among them. Brown earned the distinction as only the fifth person to fly in space six times. For Kelly, STS-103 marked his first spaceflight. Smith, Clervoy, and Grunsfeld each had flown two previous missions, Foale four including a long-duration mission aboard Mir, and Nicollier three. Smith participated in three spacewalks during the second Hubble Servicing Mission and Nicollier served as the Remote Manipulator System (RMS) or robotic arm operator during the first.
The STS-103 crew at the traditional prelaunch breakfast at NASA’s Kennedy Space Center in Florida. Suited up, the STS-103 astronauts leave crew quarters for the trip to Launch Pad 39B. Space shuttle Discovery on Launch Pad 39B, awaiting launch. Discovery arrived back to KSC at the end of the STS-96 mission on June 6, 1999, and workers towed it to the Orbiter Processing Facility the same day to begin readying it for STS-103. The vehicle rolled over to the Vehicle Assembly Building on Nov. 4, where workers mated it with its external tank and twin solid rocket boosters, before rolling the stack out to Launch Pad 39B on Nov. 13.
Liftoff of space shuttle Discovery on the STS-103 Hubble Space Telescope servicing mission 3A. The Hubble Space Telescope as Discovery approaches. The STS-103 crew berthing the Hubble into the payload bay. Beginning its 27th trip into space, Discovery lifted off from Launch Pad 39B at 7:50 p.m. EST on Dec. 19 to fix the ailing space telescope. Two days later, Brown and Kelly maneuvered Discovery to within range of Hubble so Clervoy operating the 50-foot-long RMS could grapple the telescope and berth it into the payload bay.
During the first spacewalk, astronauts John M. Grunsfeld, left, and Steven L. Smith replacing one of the Rate Sensor Units containing two gyroscopes. Smith gives a thumbs up with his image reflected in the Hubble Space Telescope. Smith and Grunsfeld conducted the mission’s first spacewalk on Dec. 22, the flight’s fourth day in space. The duo, aided by Clervoy operating the RMS from inside Discovery, completed two of mission’s highest priority objectives. They replaced the failed gyroscopes, installing three new Rate Sensor Units, each containing two gyroscopes, to return control to the ailing telescope. They also installed six Voltage/Temperature Improvement Kits to prevent the telescope’s batteries from overheating as they aged. The excursion lasted eight hours 15 minutes, at the time the second longest spacewalk.
During the second spacewalk, astronauts C. Michael Foale, left, and Claude Nicollier during the changeout of the fine guidance sensor. Foale at the end of the Remote Manipulator System services the Hubble Space Telescope. The next day, Nicollier and Foale conducted the mission’s second spacewalk. The main task for this excursion involved installing a new computer aboard Hubble, replacing the original 1970s vintage unit. The new radiation-hardened system ran 20 times faster and carried six times more memory while using one-third the electrical power. They also installed a fine guidance sensor before concluding the eight-hour 10-minute spacewalk.
Astronauts Steven L. Smith, left, and John M. Grunsfeld begin their servicing activities during the third spacewalk. At the end of the third and final spacewalk, Grunsfeld, left, and Smith provide closing comments about the work the mission accomplished to service the Hubble Space Telescope. Smith and Grunsfeld ventured outside for a second time to complete the flight’s third and final spacewalk on Dec. 24, the first spacewalk conducted on Christmas Eve day. First, they replaced an old reel-to-reel tape recorder with a solid state unit providing a 10-fold increase in recording capability and replaced a failed data transmitter. They installed seven new covers on Hubble’s electronics bay doors for added protection of the telescope’s insulation. This third spacewalk lasted eight hours eight minutes.
The first space shuttle crew to celebrate Christmas in space, the STS-103 astronauts pose wearing Santa hats. The Hubble Space Telescope shortly after the STS-103 crew released it. The next day, the STS-103 astronauts earned the distinction as the first space shuttle crew to spend Christmas Day in space. Clervoy grappled Hubble, lifted it out of the payload bay and released it to continue its mission. Hubble Space Telescope Program Manager John H. Campbell said after the release, “The spacecraft is being guided by its new gyros under the control of its brand new computer. [It] is now orbiting freely and is in fantastic shape.” After deploying Hubble, the astronauts enjoyed a well-deserved Christmas dinner, with Clervoy providing French delicacies. The crew spent Dec. 26 readying Discovery for its return to Earth, including testing its reaction control system thrusters and aerodynamic surfaces and stowing unneeded gear.
Astronauts Steven L. Smith, left, Claude Nicollier, and John M. Grunsfeld complete their fluid loading protocol and put on their launch and entry suits prior to reentry. Space shuttle Discovery makes a perfect night landing at NASA’s Kennedy Space Center in Florida. The crew welcome home ceremony at Ellington Field in Houston. On Dec. 27, the astronauts donned their launch and entry suits and prepared for the return to Earth. They closed the payload bay doors and fired Discovery’s engines to bring them out of orbit. Just before landing, Kelly lowered the craft’s landing gear and Brown guided Discovery to a smooth night landing at KSC, concluding a flight of seven days, 23 hours, 11 minutes. They circled the Earth 119 times. The flight marked Discovery’s last solo flight as all its subsequent missions docked with the International Space Station. Workers at KSC began readying it for its next mission, STS-92 in October 2000.
The Hubble Space Telescope continues to operate today, far exceeding the five-year life extension expected from the last of the servicing missions in 2009. Joined in space by the James Webb Space Telescope in 2021, the two instruments together continue to image the skies across a broad range of the electromagnetic spectrum to provide scientists with the tools to gain unprecedented insights into the universe and its formation.
Watch the STS-103 crew narrate a video of their Hubble servicing mission.
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By NASA
5 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
The Orion Environmental Test Article photographed inside the Thermal Vacuum Chamber on April 11, 2024, in the Space Environments Complex at NASA’s Neil Armstrong Test Facility in Sandusky, Ohio. Credit: NASA/Quentin Schwinn Making the voyage 1.4 million miles around the Moon and back — the farthest a spacecraft built for humans has ever gone — the Orion spacecraft has faced a battery of tests over the years. Though Orion successfully proved its capabilities in the harsh environment of space during the Artemis I mission, Orion’s evaluation did not end at splashdown.
The crew module, now known as the Orion Environmental Test Article (ETA), returned to NASA’s Neil Armstrong Test Facility in Sandusky, Ohio, in January 2024 and completed an 11-month test campaign necessary for the safety and success of Artemis II, the first crewed mission under NASA’s Artemis campaign.
Engineers and technicians from NASA and Lockheed Martin subjected the test article to the extreme conditions Orion may experience in a launch abort scenario. In the event of an emergency, Orion — and astronauts inside — will jettison away from the SLS (Space Launch System) rocket for a safe landing in the ocean.
Experts at NASA’s Neil Armstrong Test Facility in Sandusky, Ohio, conducted a lightning test, which simulates the electromagnetic effects of a lightning strike to the vehicle on the launch pad awaiting liftoff. The Feb. 20, 2024 test proved the grounding path of the vehicle is operating as designed and protecting the vehicle from damage to any of its equipment or systems. Credit: NASA/Quentin Schwinn Experts installed NASA’s Launch Abort System, designed to carry the crew to safety in the event of an emergency during launch or ascent. The Orion test article was subjected to acoustic levels simulating both a nominal ascent and a launch abort scenario. The acoustic test chamber at NASA’s Neil Armstrong Test Facility in Sandusky, Ohio, blasted the test article at a volume of almost 164 decibels on Sept. 9, 2024. Credit: NASA/Jordan Salkin On Nov. 11, 2024, experts successfully at NASA’s Neil Armstrong Test Facility completed the docking mechanism jettison test, designed to connect and disconnect the Orion spacecraft to Gateway, a small space station that will orbit the Moon. They also completed the forward bay cover jettison test on Nov. 23, 2024, which is the last piece that must eject right before parachutes deploy, and successfully tested Orion’s uprighting system. Credit: NASA/Jordan Salkin “This event would be the maximum stress and highest load that any of the systems would see,” said Robert Overy, Orion ETA project manager, NASA’s Glenn Research Center in Cleveland. “We’re taking a proven vehicle from a successful flight and pushing it to its limits. The safety of the astronaut crew depends on this test campaign.”
Experts conducted tests that simulated the noise levels of an abort during launch in addition to the electromagnetic effects of lightning strikes. The test campaign also jettisoned the test article’s docking module and parachute covers, as well as the crew module uprighting system, which consists of five airbags on top of the spacecraft that inflate upon splashdown.
“It’s been a successful test campaign,” Overy said. “The data has matched the prediction models, and everything operated as expected after being subjected to nominal and launch abort acoustic levels. We are still analyzing data, but the preliminary results show the vehicle and facility operated as desired.”
On. Nov. 23, 2024, after subjecting the Orion test article to launch abort-level acoustics, experts tested the functionality of the forward bay cover, which is the last piece that must eject before parachutes deploy. Credit: NASA/Jordan Salkin and Quentin Schwinn Testing Orion at such high acoustic levels was a major milestone for Artemis. The Reverberant Acoustic Test Facility, the world’s most powerful spacecraft acoustic test chamber, was built in 2011 in anticipation of this specific test campaign.
“These tests are absolutely critical because we have to complete all of these tests to say the spacecraft design is safe and we’re ready to fly a crew for the first time on Artemis II,” said Michael See, ETA vehicle manager, Orion Program. “This is the first time we’ve been able to test a spacecraft on the ground in such an extreme abort-level acoustic environment.”
The Orion Environmental Test Article with Launch Abort System installed moves to the Reverberant Acoustic Test Facility, the most powerful spacecraft acoustic test chamber in the world, on Sept. 9, 2024, at NASA’s Neil Armstrong Test Facility in Sandusky, Ohio. Credit: NASA/Jordan Salkin and Quentin Schwinn Part of NASA Glenn, Armstrong Test Facility is home to the world’s largest and most powerful space environment simulation chambers capable of testing full-sized spacecraft for all the extreme conditions of launch and spaceflight. The facility not only houses an acoustic test chamber, but also a thermal-vacuum chamber and spacecraft vibration system.
“The facility is unique because there’s no other place in the world capable of testing spacecraft like this,” Overy said. “Armstrong Test Facility is a one-stop-shop for all your testing needs to prepare your spacecraft for the severe and challenging journey to and from space.”
Orion’s Round-Trip Journey to Ohio
This is not the first time Orion has been inside the walls of the Space Environments Complex at Armstrong Test Facility. The spacecraft underwent mission-critical testing in 2019, where it was subjected to extreme temperatures and an electromagnetic environment before it launched on Artemis I in 2022.
“I remember when it first arrived, the gravity of its importance really hit home,” said Joshua Pawlak, test manager, NASA Glenn. “I thought to myself, on future Artemis missions, astronauts will be inside Orion heading to the Moon, and they’ll be depending on it for survival.”
Pawlak was a mechanical test engineer when Orion made its first trip to the Sandusky facility. He participated in planning and coordinating testing of the vehicle and trained personnel. He managed the vehicle from the moment it arrived, through testing, and up until it departed for NASA’s Kennedy Space Center in Florida.
Joshua Pawlak poses in front of the Artemis I Space Launch System rocket on Nov. 16, 2022, in Cape Canaveral, Florida. Credit: Joshua Pawlak “When it returned, I felt like I had a small part in this really big and exciting thing,” Pawlak said. “Seeing it come back blackened and scarred from the harsh environment of space was incredible. Space is not a friendly space, and I felt proud knowing that if there were astronauts on that vehicle, they would have survived.
After the Orion test article departs from Glenn, it will head to Kennedy for additional testing.
“When Artemis II launches and those astronauts are sitting on board, I’ll know that I did everything I could to ensure the vehicle is ready for them and going to perform as expected,” Pawlak said. “That’s why I do what I do.”
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By Space Force
The mission successfully achieved a complex effort across multiple Space Force organizations to pull an existing GPS III satellite from storage, accelerate integration and launch vehicle readiness, and rapidly process for launch.
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By NASA
This article is from the 2024 Technical Update
Autonomous flight termination systems (AFTS) are being progressively employed onboard launch vehicles to replace ground personnel and infrastructure needed to terminate flight or destruct the vehicle should an anomaly occur. This automation uses on-board real-time data and encoded logic to determine if the flight should be self-terminated. For uncrewed launch vehicles, FTS systems are required to protect the public and governed by the United States Space Force (USSF). For crewed missions, NASA must augment range AFTS requirements for crew safety and certify each flight according to human rating standards, thus adding unique requirements for reuse of software originally intended for uncrewed missions. This bulletin summarizes new information relating to AFTS to raise awareness of key distinctions, summarize considerations and outline best practices for incorporating AFTS into human-rated systems.
Key Distinctions – Crewed v. Uncrewed
There are inherent behavioral differences between uncrewed and crewed AFTS related to design philosophy and fault tolerance. Uncrewed AFTS generally favor fault tolerance against failure-to-destruct over failing silent
in the presence of faults. This tenet permeates the design, even downto the software unit level. Uncrewed AFTS become zero-fault-to-destruct tolerant to many unrecoverable AFTS errors, whereas general single fault
tolerance against vehicle destruct is required for crewed missions. Additionally, unique needs to delay destruction for crew escape, provide abort options and special rules, and assess human-in-the-loop insight, command, and/or override throughout a launch sequence must be considered and introduces additional requirements and integration complexities.
AFTS Software Architecture Components and Best-Practice Use Guidelines
A detailed study of the sole AFTS currently approved by USSF and utilized/planned for several launch vehicles was conducted to understand its characteristics, and any unique risk and mitigation techniques for effective human-rating reuse. While alternate software systems may be designed in the future, this summary focuses on an architecture employing the Core Autonomous Safety Software (CASS). Considerations herein are intended for extrapolation to future systems. Components of the AFTS software architecture are shown, consisting of the CASS, “Wrapper”, and Mission Data Load (MDL) along with key characteristics and use guidelines. A more comprehensive description of each and recommendations for developmental use is found in Ref. 1.
Best Practices Certifying AFTS Software
Below are non-exhaustive guidelines to help achieve a human-rating
certification for an AFTS.
References
NASA/TP-20240009981: Best Practices and Considerations for Using
Autonomous Flight Termination Software In Crewed Launch Vehicles
https://ntrs.nasa.gov/citations/20240009981 “Launch Safety,” 14 C.F.R., § 417 (2024). NPR 8705.2C, Human-Rating Requirements for Space Systems, Jul 2017,
nodis3.gsfc.nasa.gov/ NASA Software Engineering Requirements, NPR 7150.2D, Mar 2022,
nodis3.gsfc.nasa.gov/ RCC 319-19 Flight Termination Systems Commonality Standard, White
Sands, NM, June 2019. “Considerations for Software Fault Prevention and Tolerance”, NESC
Technical Bulletin No. 23-06 https://ntrs.nasa.gov/citations/20230013383 “Safety Considerations when Repurposing Commercially Available Flight
Termination Systems from Uncrewed to Crewed Launch Vehicles”, NESC
Technical Bulletin No. 23-02 https://ntrs.nasa.gov/citations/20230001890 View the full article
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