TYB
NASA Astronomy Picture of the Day
August 8, 2024
Periodic Comet Swift-Tuttle
A Halley-type comet with an orbital period of about 133 years, Comet 109P/Swift-Tuttle is recognized as the parent of the annual Perseid Meteor Shower. The comet's last visit to the inner Solar System was in 1992. Then, it did not become easily visible to the naked eye, but it did become bright enough to see from most locations with binoculars and small telescopes. This stunning color image of Swift-Tuttle's greenish coma, long ion tail and dust tail was recorded using film on November 24, 1992. That was about 16 days after the large periodic comet's closest approach to Earth. Comet Swift-Tuttle is expected to next make an impressive appearance in night skies in 2126. Meanwhile, dusty cometary debris left along the orbit of Swift-Tuttle will continue to be swept up creating planet Earth's best-known July and August meteor shower.
https://apod.nasa.gov/apod/astropix.html?
NASA considering returning Starliner astronauts on Crew Dragon
August 7, 2024
NASA is evaluating options to have the two astronauts who flew to the International Space Station on a Boeing CST-100 Starliner spacecraft return instead on a SpaceX Crew Dragon in early 2025, given questions about the safety of Starliner.
At a Aug. 7 briefing, NASA officials said they expect to decide around the middle of August if it is too risky to have astronauts Butch Wilmore and Suni Williams, who arrived at the station two months ago on Starliner, to return on the same spacecraft.
That would require them to stay on the station while Starliner performs an automated undocking and return to Earth.
In that scenario, NASA would fly the Crew-9 mission, whose launch was delayed one day earlier from Aug. 18 to no earlier than Sept. 24, with two people instead of four.
Williams and Wilmore would then return with Crew-9 at the end of its scheduled mission in early 2025.
Officials declined to disclose which of the current members of Crew-9 would be retained in that scenario and who would be reassigned to later missions.
NASA is considering that option because of continued concerns about the performance of reaction control system (RCS) thrusters on Starliner.
Several of the thrusters malfunctioned during the spacecraft’s approach to the station in June, although all but one have since been restored.
Uncertainty about what caused the thrusters’ performance to drop is driving the ongoing discussions about the safety of returning crew on Starliner, including how the thrusters will perform on the return or “downhill” phase.
“People really want to understand the physics of what’s going on” in the thruster, said Steve Stich, NASA commercial crew program manager, “and then look ahead to the downhill phase and the heating phase, and seeing if we can model that on the downhill phase and ensure that we have good thrusters.”
Tests performed on RCS thrusters last month at NASA’s White Sands Test Facility showed that heating of the thrusters could cause a Teflon seal or poppet to expand and extrude, restricting the flow of propellant.
Heating of the propellant could also cause it to vaporize, reducing thruster performance.
Those thruster tests were intended to provide reassurance that the thrusters would perform as required on the return phase, but may have done the opposite.
“The testing at White Sands and the discovery that the poppet Teflon was extruding after the testing was a bit of a surprise to us,” Stich said. “That, I would say, upped the level of discomfort.”
He said NASA has brought in propulsion experts from elsewhere in the agency to review data while additional testing is ongoing.
The goal is to try to understand what is going on in the thruster and to see if there are any other failure modes possible when the thrusters get hot.
Stich described the worst-case scenario for Starliner as an “integrated failure mechanism” between the thruster issues and separate helium leaks in the propulsion system that could create difficulties maintaining orientation of the spacecraft during its deorbit burn.
“The team wants to understand the worst-case ramifications of getting the thruster hot,” he said.
“They want to make sure there’s no particular failure mode if the thruster gets too hot that we haven’t seen yet.”
That uncertainty stands in contrast to Boeing’s comments on the performance of the thrusters.
In an Aug. 2 statement, Boeing discussed extensive testing of the thrusters that led the company to conclude the spacecraft retains “safe undocking and landing capabilities” for this mission.
“Boeing remains confident in the Starliner spacecraft and its ability to return safely with crew,” it stated.
“Reasonable people could have different views on which path we should take,” said Ken Bowersox, NASA associate administrator for space operations, on the call, which did not include a Boeing representative.
“The Boeing team, because of their experience and their belief in their hardware, would take them to being very confident that the vehicle could bring the crew home, even right now with the uncertainty that we’ve got,” he said.
“But we’ve got other folks that are probably a little more conservative. They’re worried that we don’t know for sure, so they estimate the risk higher.”
“Boeing asserted their vehicle was ready to come home on Friday,” Stich said, referring to the date of the Boeing statement.
“I think it depends on your experience base a little bit as to how you view the risk.”
https://spacenews.com/nasa-considering-returning-starliner-astronauts-on-crew-dragon/
Electra Demonstrates eSTOL Aircraft Capabilities at NASA Langley
August 8, 2024
Electra.aero Inc. successfully demonstracted its EL-2 Goldfinch hybrid-electric short takeoff and landing (eSTOL) technology demonstrator aircraft at NASA’s Langley Research Center on July 15th.
The achievement marks the first flight of an electric aircraft with a pilot onboard at NASA Langley.
Electra and NASA are collaborating on several aviation-related projects.
Under a NASA Space Act Agreement, the companies are jointly conducting research, demonstrations, and information sharing in the field of Advanced Air Mobility (AAM).
Additionally, Electra is working on a NASA Small Business Innovation Research (SBIR) project to develop a solar-electric, high-altitude, long-endurance aircraft known as a High-Altitude Platform Station (HAPS).
The company has also contributed to a NASA study exploring the potential of Regional Air Mobility (RAM) to improve transportation connectivity.
The demonstration highlighted the aircraft’s use of distributed electric propulsion (DEP) and blown lift technology, enabling short takeoffs and landings of under 150 feet.
The aircraft’s hybrid-electric system was demonstrated, showcasing potential for longer range flights, while its battery-electric mode offers quiet, community-friendly operations.
Earlier in the day, the aircraft completed a 120-mile flight from Electra’s Manassas, Virginia facility to NASA in Hampton, Virginia using its hybrid propulsion system.
Electra is developing a nine-passenger eSTOL production aircraft designed to replace short and medium-distance car travel, up to 500 miles, with faster, quieter, and more environmentally friendly air transportation.
This aircraft has the potential to significantly reduce travel times between locations like Northern Virginia and Hampton Roads, offering a 35-minute flight alternative to the current 2.5-hour drive.
https://flightplan.forecastinternational.com/2024/08/08/electra-demonstrates-estol-aircraft-capabilities-at-nasa-langley/
NASA Optical Navigation Tech Could Streamline Planetary Exploration
Aug 07, 2024
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As astronauts and rovers explore uncharted worlds, finding new ways of navigating these bodies is essential in the absence of traditional navigation systems like GPS.
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Optical navigation relying on data from cameras and other sensors can help spacecraft — and in some cases, astronauts themselves — find their way in areas that would be difficult to navigate with the naked eye.
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Three NASA researchers are pushing optical navigation tech further, by making cutting edge advancements in 3D environment modeling, navigation using photography, and deep learning image analysis.
In a dim, barren landscape like the surface of the Moon, it can be easy to get lost.
With few discernable landmarks to navigate with the naked eye, astronauts and rovers must rely on other means to plot a course.
As NASA pursues its Moon to Mars missions, encompassing exploration of the lunar surface and the first steps on the Red Planet, finding novel and efficient ways of navigating these new terrains will be essential.
That’s where optical navigation comes in — a technology that helps map out new areas using sensor data.
NASA’s Goddard Space Flight Center in Greenbelt, Maryland, is a leading developer of optical navigation technology.
For example, GIANT (the Goddard Image Analysis and Navigation Tool) helped guide the OSIRIS-REx mission to a safe sample collection at asteroid Bennu by generating 3D maps of the surface and calculating precise distances to targets.
Now, three research teams at Goddard are pushing optical navigation technology even further.
Virtual World Development
Chris Gnam, an intern at NASA Goddard, leads development on a modeling engine called Vira that already renders large, 3D environments about 100 times faster than GIANT.
These digital environments can be used to evaluate potential landing areas, simulate solar radiation, and more.
While consumer-grade graphics engines, like those used for video game development, quickly render large environments, most cannot provide the detail necessary for scientific analysis.
For scientists planning a planetary landing, every detail is critical.
“Vira combines the speed and efficiency of consumer graphics modelers with the scientific accuracy of GIANT,” Gnam said.
“This tool will allow scientists to quickly model complex environments like planetary surfaces.”
The Vira modeling engine is being used to assist with the development of LuNaMaps (Lunar Navigation Maps).
This project seeks to improve the quality of maps of the lunar South Pole region which are a key exploration target of NASA’s Artemis missions.
Vira also uses ray tracing to model how light will behave in a simulated environment.
While ray tracing is often used in video game development, Vira utilizes it to model solar radiation pressure, which refers to changes in momentum to a spacecraft caused by sunlight.
Find Your Way with a Photo
Another team at Goddard is developing a tool to enable navigation based on images of the horizon.
Andrew Liounis, an optical navigation product design lead, leads the team, working alongside NASA Interns Andrew Tennenbaum and Will Driessen, as well as Alvin Yew, the gas processing lead for NASA’s DAVINCI mission.
An astronaut or rover using this algorithm could take one picture of the horizon, which the program would compare to a map of the explored area.
The algorithm would then output the estimated location of where the photo was taken.
Using one photo, the algorithm can output with accuracy around hundreds of feet. Current work is attempting to prove that using two or more pictures, the algorithm can pinpoint the location with accuracy around tens of feet.
“We take the data points from the image and compare them to the data points on a map of the area,” Liounis explained.
“It’s almost like how GPS uses triangulation, but instead of having multiple observers to triangulate one object, you have multiple observations from a single observer, so we’re figuring out where the lines of sight intersect.”
This type of technology could be useful for lunar exploration, where it is difficult to rely on GPS signals for location determination.
A Visual Perception Algorithm to Detect Craters
To automate optical navigation and visual perception processes, Goddard intern Timothy Chase is developing a programming tool called GAVIN (Goddard AI Verification and Integration) Tool Suit.
This tool helps build deep learning models, a type of machine learning algorithm that is trained to process inputs like a human brain.
In addition to developing the tool itself, Chase and his team are building a deep learning algorithm using GAVIN that will identify craters in poorly lit areas, such as the Moon.
https://www.nasa.gov/technology/goddard-tech/nasa-optical-navigation-tech-could-streamline-planetary-exploration/
Chinese megaconstellation launch creates field of space debris
August 8, 2024
A Chinese launch to deploy a first batch of communications satellites has created more than 50 pieces of debris which could threaten spacecraft in low Earth orbit.
The Long March 6A launched Aug. 6, from a specifically constructed launch pad at Taiyuan spaceport.
The rocket’s upper stage, modified for restarts and deploying numerous satellites, deployed 18 flat panel Qianfan (“Thousand Sails”), or G60, satellites into roughly 800-kilometer-altitude polar orbit for Shanghai Spacecom Satellite Technology (SSST).
The satellites are the first of a planned megaconstellation of more than 14,000 low Earth orbit (LEO) communications satellites.
However the mission appears to have created a string of debris along its orbital path, according to observations from Slingshot Aerospace, a space-tracking and data analytics firm.
“Composite images from Slingshot’s LEO-focused Horus optical fences show a series of bright, unexpected objects moving along the same orbital path as the rocket body and the G60 satellites it deployed,” Slingshot Aerospace noted in a statement.
The event has more than 50 pieces of debris that now pose a risk to LEO constellations below 800 km altitude, according to the firm.
“These uncued detections have allowed Slingshot to execute additional tasking on these objects to gather more detailed information that will support subsequent tracking and object characterization.”
U.S. Space Forces – Space (S4S) tracking confirmed the breakup of the Long March 6A rocket stage.
“The breakup likely occurred Aug. 7, at 1548 UTC. The tracked pieces are being incorporated into routine conjunction assessment to support spaceflight safety.
There are currently no threats to human spaceflight. Analysis is ongoing,” the statement read.
Space debris at such altitudes, where there is very little atmospheric drag, can remain in orbit for decades or longer, depending on the size and density of the debris and other variables.
Any impact with spacecraft could cause serious damage and create further debris, with the debris likely traveling at around 7.5 kilometers per second, or 27,000 km per hour.
The debris incident is the latest of several events affecting the upper stage of the Long March 6A. An early July saw numerous pieces of debris created, detected by Swiss firm S2a systems and reported by SpaceNews.
The state-owned Shanghai Academy of Spaceflight Technology (SAST) which designed and produces the rocket has yet to respond to a request for comment on the earlier incident.
A Long March 6A upper stage breakup event in November 2022 meanwhile created hundreds of pieces of debris.
SSST plans to launch a further 90 satellites this year, according to earlier statements.
Documentation filed with the International Telecommunication Union (ITU) sets out plans for a first phase using 36 polar orbital planes, each filled with 36 satellites, totaling 1,296 spacecraft.
The overall plan is for more than 14,000 satellites. It is unknown what launchers the satellites will fly on. The potential frequent use of the Long March 6A, however, raises concerns.
“If even a fraction of the launches required to field this Chinese megaconstellation generate as much debris as this first launch, the result would be an untenable addition to the space debris population in LEO,” Audrey Schaffer, Vice President of Strategy and Policy, said in a statement to SpaceNews.
“Events like this highlight the importance of adherence to existing space debris mitigation guidelines to reduce the creation of new space debris and underscore the need for robust space domain awareness capabilities to rapidly detect, track, and catalog newly-launched space objects so they can be screened for potential conjunctions.”
SSST’s G60 or Thousand Sails is just one of the megaconstellations planned by China in response to Starlink. Launches for the national Guowang (“national net”) 13,000-satellite project are also expected in the future.
https://spacenews.com/chinese-megaconstellation-launch-creates-field-of-space-debris/
U.S. Army gears up for space warfare, drawing lessons from Ukraine
August 7, 2024
The U.S. Army is taking cues from the ongoing conflict in Ukraine to prepare for a new era of space-based warfare.
“The war in Ukraine has given us a stark warning: the character of war is changing,” said Col. Princeton Wright, capability manager for space and high altitude at the Army’s Space and Missile Defense Command (SMDC).
Wright spoke during a panel discussion Aug. 6 at the Space and Missile Defense Conference in Huntsville, Alabama.
The conflict in Ukraine has served as a stark demonstration of modern electronic warfare capabilities, with Russia’s deployment of jamming systems and other disruptive technologies offering a sobering preview of future combat scenarios.
U.S. military planners now anticipate that rival powers will adopt similar tactics in future conflicts, potentially leaving American forces in electronically contested environments where reliable satellite communications and navigation are no longer guaranteed.
The U.S. military also is interested in advanced technologies like tactical lasers to disrupt enemy imaging satellites, a capability that could prove crucial in denying adversaries the benefits of space-based reconnaissance.
“The brutal and complex nature of this conflict has demonstrated that traditional modes of warfare are being supplemented — and in some cases, supplanted — by new technologies and strategies,” said Wright.
Dual-pronged strategy
As the largest consumer of satellite services within the U.S. military, the Army relies heavily on space-based assets for critical functions including communications, navigation, weather forecasting, and early missile launch detection.
This dependence has led to a dual-pronged approach in the Army’s space strategy.
On one hand, the service plans to work with the other branches of the military to develop tactics and technologies to safeguard U.S. satellite signals from potential disruptions, ensuring continued access to these vital resources during conflicts.
On the other hand, the Army is also exploring offensive capabilities that could potentially deny adversaries access to their own satellite networks in times of war.
Wright pointed at the Army’s recent guidance on the role of space in land warfare which focuses on two primary objectives: integrating space capabilities into ground forces’ operations and developing ways to interdict adversary space assets.
The Army is also looking at concepts such as using high-altitude platforms — drones or balloons — equipped with jammers to disrupt adversary navigation satellite signals.
The idea of using high-altitude balloons or airships for military purposes isn’t new, but it has recently gained renewed interest following the establishment of the U.S. Space Force and subsequent realignment of satellite ownership and operations.
With the Space Force now responsible for satellite acquisitions, the Army is exploring more cost-effective alternatives like airships to deploy sensors or jamming equipment.
Seeking industry help
Wright emphasized the need for collaboration with industry and academia on a number of space-focused technologies identified by SMDC’s Center of Excellence.
This includes developing systems that can operate effectively in various theaters, from Europe to the Indo-Pacific and even the Arctic.
In its “Space Vision” document published earlier this year, the Army for the first time has explicitly expressed interest in developing offensive capabilities that could potentially deny adversaries access to their surveillance satellites during conflicts.
This stance appears to be influenced by the Army’s Pacific Command, which has been a driving force behind the organization of “multi-domain” task forces.
These experimental units are designed to be equipped with asymmetric or unconventional weapons and tactics, aimed at countering an opposing force’s advantages in warfare.
https://spacenews.com/u-s-army-gears-up-for-space-warfare-drawing-lessons-from-ukraine/
Actually, we outsource to the mechanic / doctor.
Would be nice to put it back in our own hands though.