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Dodging debris to keep satellites safe
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By European Space Agency
The European Galileo satellite navigation system Galileo keeps growing: a new pair of satellites has joined the constellation after a journey on a Falcon 9 rocket, launched from the Kennedy Space Center in Florida on 18 September at 00:50 CEST (17 September 18:50 local time).
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By European Space Agency
In 2022 NASA’s DART spacecraft made history, and changed the Solar System forever, by impacting the Dimorphos asteroid and measurably shifting its orbit around the larger Didymos asteroid. In the process a plume of debris was thrown out into space.
The latest modelling, available on the preprint server arXiv and accepted for publication in the September volume of The Planetary Science Journal, shows how small meteoroids from that debris could eventually reach both Mars and Earth – potentially in an observable (although quite safe) manner.
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By European Space Agency
The two new Galileo satellites launched in April have entered service, completing the second of three constellation planes. With every addition to the constellation, the precision, availability and robustness of the Galileo signal is improved. The next launch is planned in the coming weeks and the remaining six Galileo First Generation satellites will join the constellation in the next years.
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By NASA
Teams with NASA’s Exploration Ground Systems Program, in preparation for the agency’s Artemis II crewed mission to the Moon, begin installing the first of four emergency egress baskets on the mobile launcher at Launch Complex 39B at the agency’s Kennedy Space Center in Florida on Wednesday, Jan. 24, 2024. The baskets, similar to gondolas on ski lifts, are used in the case of a pad abort emergency to enable astronauts and other pad personnel a way to quickly escape away from the mobile launcher to the base of the pad and where waiting emergency transport vehicles will then drive them away.NASA/Isaac Watson Recently, teams with NASA’s Exploration Ground Systems (EGS) Program at the agency’s Kennedy Space Center met with engineering teams at a central Florida amusement park to share knowledge on a new braking system NASA is using for its launch pad emergency egress system for Artemis missions.
“We have a new magnetic braking system for the Artemis emergency egress system and NASA hasn’t used this technology on the ground infrastructure side before to support launches,” said Jesse Berdis, mobile launcher 1 deputy project manager for EGS. “I realized we have neighbors 50 miles from us in Orlando that are essentially the world experts on magnetic braking systems.”
For Artemis, teams will use a track cable that connects the mobile launcher to the terminus site near the perimeter of NASA Kennedy’s Launch Pad 39B, where four baskets, similar to gondola lifts, can ride down. This is where the magnetic braking system operates to help control the acceleration of the baskets in multiple weight and environmental conditions. At the pad terminus site, armored emergency response vehicles are stationed to take personnel safely away from the launch pad to a designated safe site at Kennedy.
Many roller coaster manufacturers employ the use of an “eddy current braking system,” which involves using magnetics to help slow down a vehicle. Though the applications used on the roller coasters differ slightly from what the EGS teams are using for Artemis, the concept is the same, explained Amanda Arrieta, mobile launcher 1 senior element engineer.
However, unlike roller coasters which are typically in use daily for multiple hours on end, the Artemis emergency egress system is there for emergency situations only.
“We don’t plan to ever run our system unless we’re testing it or performing maintenance,” Berdis said.
Regardless of this, teams at Kennedy have ensured the system is able to function for years to come to support future Artemis missions.
“The maintenance crews [at the amusement park] were awesome because they showed us their nightly, monthly, and yearly inspections on what they were doing,” Berdis said. “That gave our operations teams a really good foundation and baseline knowledge of what to expect when they maintain and operate this system for the Artemis missions.”
Some of the conversations and suggestions teams shared include adding an acceleration sensor in the emergency egress baskets during testing. The sensor will help detect how fast the baskets are going when they ride down.
The emergency egress system is one of several new additions the EGS team is implementing to prepare for future crewed missions starting with Artemis II, and this system especially emphasizes the importance of safety.
“We have a mission, and a part of that mission is in case of an emergency, which we don’t expect, is to protect our astronauts and supporting teams at the launch pad,” Berdis said. “We want our teams to be safe and, for any scenario we put them in, especially on the ground infrastructure side, it’s important for us to do our due diligence. That includes talking to other groups that are the experts in their field to ensure we have looked at all possibilities across the board to ensure our mission is a safe one for our teams.”
During the Space Shuttle Program, teams used a similar system for the escape route astronauts and other personnel take in the event of an emergency during a launch countdown. However, instead of using a magnetic braking system for the baskets, teams used a mechanical braking system, which involved using a catch net and drag chain to slow and then halt the baskets sliding down the wire.
For the agency’s Commercial Crew Program, SpaceX also uses a catch net and drag chain for its slidewire cable at NASA Kennedy’s Launch Complex 39A pad and a deployable chute at Space Launch Complex 40 at Cape Canaveral Space Force Station. Boeing and United Launch Alliance also use a slidewire, but instead of baskets, the team deploys seats, like riding down a zip line, that ride down the slide wires at Space Launch Complex 41 at Cape Canaveral Space Force Station.
Under NASA’s Artemis campaign, the agency will establish the foundation for long-term scientific exploration at the Moon, land the first woman, first person of color, and its first international partner astronaut on the lunar surface, and prepare for human expeditions to Mars for the benefit of all.
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By NASA
3 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
NASA Johnson Space Center: ORDEM represents the state of the art in orbital debris models intended for engineering analysis. It is a data-driven model, relying on large quantities of radar, optical, in situ, and laboratory measurement data. When released, it was the first software code to include a model for different orbital debris material densities, population models from low Earth orbit (LEO) all the way to Geosynchronous orbit (GEO), and uncertainties in each debris population.
ORDEM allows users to compute the orbital debris flux on any satellite in Earth orbit. This allows satellite designers to mitigate possible orbital debris damage to a spacecraft and its instruments using shielding and design choices, thereby extending the useful life of the mission and its experiments. The model also has a mode that simulates debris telescope/radar observations from the ground. Both it and the spacecraft flux mode can be used to design experiments to measure the meteoroid and orbital debris environments.
ORDEM is used heavily in the hypervelocity protection community, those that design, build, and test shielding for spacecraft and rocket upper stages. The fidelity of the ORDEM model allows for the optimization of shielding to balance mission success criteria, risk posture, and cost considerations.
As both government and civilian actors continue to exploit the space environment for security, science, and the economy, it is important that we track the debris risks in increasingly crowded orbits, in order to minimize damage to these space assets to make sure these missions continue to operate safely. ORDEM is NASA’s primary tool for computing and mitigating these risks.
ORDEM is used by NASA, the Department of Defense, and other U.S. government agencies, directly or indirectly (via the Debris Assessment Software, MSC-26690-1) to evaluate collision risk for large trackable objects, as well as other mission-ending risks associated with small debris (such as tank ruptures or wiring cuts). In addition to the use as an engineering tool, ORDEM has been used by NASA and other missions in the conceptual design phase to analyze the frequency of orbital debris impacts on potential in situ sensors that could detect debris too small to be detected from ground-based assets.
Commercial and academic users of ORDEM include Boeing, SpaceX, Northrop Grumman, the University of Colorado, California Polytechnic State University, among many others. These end users, similar to the government users discussed above, use the software to (1) directly determine potential hazards to spaceflight resulting from flying through the debris environment, and (2) research how the debris environment varies over time to better understand what behaviors may be able to mitigate the growth of the environment.
The quality and quantity of data available to the NASA Orbital Debris Program Office (ODPO) for the building, verification, and validation of the ORDEM model is greater than for any other entity that performs similar research. Many of the models used by other research and engineering organizations are derived from the models that ODPO has published after developing them for use in ORDEM.
ORDEM Team
Alyssa Manis Andrew B, Vavrin Brent A. Buckalew Christopher L. Ostrom Heather Cowardin Jer-chyi Liou John H, Seago John Nicolaus Opiela Mark J. Matney, Ph.D. Matthew Horstman Phillip D. Anz-Meador, Ph.D. Quanette Juarez Paula H. Krisko, Ph.D. Yu-Lin Xu, Ph.D. Share
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Last Updated Jul 31, 2024 EditorBill Keeter Related Terms
Office of Technology, Policy and Strategy (OTPS) View the full article
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