Communication link with Japan's X-ray astronomy satellite lost: JAXA
Japan's space agency said Sunday it has experienced trouble communicating with a newly launched X-ray astronomy satellite since Saturday afternoon, making it difficult for the agency to ascertain its condition.
The "Hitomi" satellite, which was called the "Astro-H" until its successful launch on a Japanese rocket in mid-February, could be experiencing a power shortage after an unexpected shift in its posture may have made it unable to draw on solar power, it said.
The satellite is supposed to be orbiting about 580 kilometers above the Earth's surface, but the Japan Aerospace Exploration Agency said the satellite may also have deviated from its normal path.
The agency is trying to re-establish communications with the satellite, but if this situation persists, it will be unable to start astronomy observations, scheduled to begin in the summer. The agency was calibrating equipment on the satellite when it ran into the problem.
"We are taking this situation very seriously," Saku Tsuneta, director of the agency's Institute of Space and Astronautical Science, said at a news conference, adding that he does not know at this point whether a communication link can be re-established.
The Hitomi, jointly developed by JAXA, the U.S. National Aeronautics and Space Administration, and other concerns, is a space observatory instrument equipped with four X-ray telescopes and two gamma-ray detectors.
Scientists hope data obtained from the satellite will shed light on the mysteries surrounding the evolution of the universe and of black holes, which are difficult to observe directly because they emit no light.
The satellite was launched on Feb. 17 on an H-2A rocket from a space center in Kagoshima Prefecture in western Japan.
Quelle: Kyodo News
Communication failure of X-ray Astronomy Satellite “Hitomi” (ASTRO-H)
March 27, 2016 (JST)
National Research and Development Agency
Japan Aerospace Exploration Agency (JAXA)
The Japan Aerospace Exploration Agency (JAXA) found that communication with the X-ray Astronomy Satellite “Hitomi” (ASTRO-H), launched on February 17, 2016 (JST), failed from the start of its operation originally scheduled at 16:40, Saturday March 26 (JST). Up to now, JAXA has not been able to figure out the state of health of the satellite.
While the cause of communication failure is under investigation, JAXA received short signal from the satellite, and is working for recovery.
Under this circumstance, JAXA set up emergency headquarters, headed by the President, for recovery and investigation. The headquarters held its first meeting today, and has been working for recovery and the investigation of the cause. Updates will be announced as available, at the JAXA website.
At 2016 March 28, 11, Japan Aerospace Exploration Agency (JAXA) published a follow-up with respect to communication disruption of X-ray astronomy satellite which was announced the day before the "pupil". Still we have continued a situation that can not receive the radio waves from a satellite, will continue that are working on recovery and investigation of satellite communication.
In addition, the United States Department of Defense strategic military integration space operations center that is doing the monitoring, such as space debris (JSpOC) is, has confirmed five of the small object to the periphery of the "pupil", an object that was separated from the "pupil" a possible are shown. In this regard JAXA, since the JSpOC is able to receive radio waves with a short time even after the time confirming the object "pupil" is transmitted, it is set to Verifying causality.
Hitomi spinning wildly in orbit, U.S. video shows
WASHINGTON – Japan’s brand new Hitomi X-ray astronomy satellite has apparently lost control and is spinning wildly in orbit, according to a video taken by an amateur U.S. astronomer that was posted to the National Geographic website Monday.
The video shows an object that looks like Hitomi, which lost contact Saturday with the Japan Aerospace Exploration Agency (JAXA), shining and then turning extremely dark in short intervals.
The wild changes in brightness might mean its sunlight-reflecting side is moving turbulently.
“The fact that it is rotating with extreme variations in brightness indicates that it is not controlled and that some event caused it to begin its rotation,” Paul Maley, a former NASA flight controller who observed Hitomi from the ground in Arizona, was quoted as saying.
Maley, who worked for about 40 years at the Johnson Space Center, shot the footage shortly after 8 p.m. Sunday. The object was flying in the south-southeastern sky, the direction projected from Hitomi’s planned orbit.
Hitomi was designed to observe X-rays emanating from black holes and galaxy clusters. Black holes have never been directly observed, but they are believed to be collapsed stars whose enormous gravitational pull is so strong nothing can escape.
Hitomi, which JAXA jointly developed with NASA and other entities, was called Astro-H until it was put into orbit by an H-IIA rocket launched from the Tanegashima Space Center on Tanegashima Island off Kyushu on Feb. 17.
The announcement last month that gravitational waves had been detected for the first time added to evidence of their existence after scientists found the waves had been caused by two enormous black holes colliding.
Hitomi, which cost ¥31 billion ($273 million) including the cost of launching it, was supposed to orbit at an altitude of about 580 km above Earth. No other information was available as of Tuesday.
On Sunday, JAXA said that if it doesn’t re-establish communications with Hitomi, it may not be unable to start the astronomy research that was scheduled this summer. JAXA was calibrating the equipment on Hitomi when it ran into problems.
“We are taking this situation very seriously,” Saku Tsuneta, director of JAXA’s Institute of Space and Astronautical Science, said at a news conference.
Japan’s space program has achieved successes in both scientific and commercial satellite launches. It has sent astronauts on space shuttle and International Space Station missions.
Quelle: The Japan Times
U.S. military rules out collision as cause of Hitomi satellite’s woes
As Japanese ground controllers struggle to restore communications with a tumbling space telescope in orbit, the U.S. military’s space surveillance experts have eliminated one cause for the satellite’s troubles.
A military spokesperson told Spaceflight Now in an email Tuesday that the Pentagon’s space surveillance network detected no sign of a high-speed collision between Japan’s Hitomi astronomy satellite and another object in orbit late Saturday, when debris blew off the newly-launched observatory and mission control lost contact with it.
“I can confirm that we have ruled out a collision as the cause of the debris event,” wrote U.S. Air Force Capt. Nicholas Mercurio, a spokesperson for the military’s Joint Functional Component Command for Space at Vandenberg Air Force Base in California.
Mercurio said modeling and analysis by the command’s experts, akin to “rewinding the tape,” led officials to conclude the Hitomi satellite did not collide with another object prior to the appearance of the debris.
The U.S. military’s tracking radars have detected at least five objects in the vicinity of the Hitomi satellite, which launched Feb. 17 and was about halfway through a three-month calibration of its X-ray instruments when trouble struck Saturday.
The military’s Joint Space Operations Center, or JSpOC, has pinpointed the time of Hitomi’s “breakup” at around 0142 GMT Sunday (9:42 p.m. EDT Saturday), plus or minus 11 minutes.
Since then, Japanese engineers have been unable to get a stable communications lock on the satellite.
In an update posted online Tuesday, the Japan Aerospace Exploration Agency said its ground control team received two brief signals from Hitomi through the Uchinoura ground station in Japan and an antenna near Santiago, Chile, late Monday and early Tuesday.
While the short blips from Hitomi show the satellite is still alive, Japanese engineers do not know what caused the craft to lose control. With an external cause now ruled out, a fuel or gas leak, a burst battery, or some other explosive event inside the satellite is the likely culprit.
Jonathan McDowell, an astronomer at the Harvard-Smithsonian Center for Astrophysics who expertly tracks satellite activity, said the anomaly drove the Hitomi satellite slightly off course into an orbit about 5 kilometers, or 3 miles, lower than expected. That translates to a push equivalent to 4 meters per second, or 9 mph, he said on Twitter.
The event also apparently imparted a rotation on the spacecraft, meaning its antenna is not reliably pointing at Earth.
“JAXA has not been able to figure out the state of its health, as the time frames for receiving the signals were very short,” the space agency said.
Visual observations of Hitomi from the ground indicate the satellite is varying in brightness, a sign the spacecraft is likely tumbling as it orbits more than 350 miles (about 574 kilometers) above Earth.
Hitomi, also known as Astro-H, is Japan’s sixth X-ray astronomy satellite, following up on a series of observatories since 1979 that resolved the hottest parts of the universe. The ambitious mission was supposed to last three years after launching last month aboard an H-2A rocket.
“JAXA continues to investigate the relationship between the information from JSpOC and the communication anomaly,” the space agency said. “JAXA will do its best to recover communications with Hitomi and investigate the cause of the anomaly.”
Current Status of Communication Anomaly of X-ray Astronomy Satellite “Hitomi” (ASTRO-H) (Mar. 29)
JAXA has been trying to communicate with the X-ray Astronomy Satellite “Hitomi” (ASTRO-H), using ground stations both in Japan and overseas.
By utilizing two opportunities of communicating with Hitomi, JAXA received signals from the satellite: the first time was at about 10:00 p.m. on 28 at the Uchinoura Ground Station, and the second one was at around 0:30 a.m. on 29 at the Santiago Tracking Station in Chile. JAXA has not been able to figure out the state of its health, as the time frames for receiving the signals were very short.
According to the U.S. Joint Space Operations Center (JSpOC), it is estimated that Hitomi separated to five pieces at about 10:42 a.m. on 26. In order to investigate the situation, JAXA is observing the objects, using a radar located at the Kamisaibara Space Guard Center (KSGC) and telescopes at the Bisei Space Guard Center (BSGC) owned by the Japan Space Forum. Up to now, the telescopes at BSGC detected two objects around the satellite’s original orbit, while the radar at KSGC identified one of them. It is confirmed that the signal received at the Santiago Tracking Station came from the orbital direction of the object identified at KSGC.
JAXA continues to investigate the relationship between the information from JSpOC and the communication anomaly.
JAXA will do its best to recover communications with Hitomi and investigate the cause of the anomaly.
Debris appeared after Hitomi failed to keep position, JAXA says
Two pieces of debris were observed after the x-ray astronomy satellite Hitomi failed to maintain proper position, the Japan Aerospace Exploration Agency, or JAXA, said.
Data analysis showed the X-ray telescope lost positioning control at around 4:10 a.m. on March 26 Japan time and the debris appeared some six hours later, JAXA told a news conference Friday in reference to its loss of communications with Hitomi.
According to JAXA, ground radars and telescopes spotted two objects in the vicinity of the satellite. These objects are believed to have detached from Hitomi at around 10:37 a.m., almost matching the time the U.S. Joint Space Operations Center detected five objects that the space debris tracking body described as pieces of a breakup.
The possibility of space debris colliding with Hitomi is slim, JAXA said, citing information provided by the U.S. military arm.
The Japanese agency also found no problem with Hitomi’s helium tank and batteries after analyzing data it accepted before the spacecraft went silent. It now plans to check the equipment inside Hitomi, hoping for communications recovery when the solar cells resume receiving sunlight several months later.
Quelle: The Japan Times
Equipment failure, not collision, damaged X-ray satellite: JAXA
Japan's unresponsive X-ray astronomy satellite has likely been damaged by equipment failure rather than by a collision with space junk, the country's space agency said Friday.
The Hitomi satellite, launched in February, lost its communication link with Earth last week.
"After becoming unable to stabilize itself, (the satellite) sustained some sort of damage," an official of the Japan Aerospace Exploration Agency said.
Possible failures could include a rupture of the helium tank that houses the X-ray telescopes, a fuel leak in the stabilizing engines or a battery fault, JAXA said.
Several objects up to a meter wide spotted floating nearby by U.S. military trackers and JAXA are highly likely to be pieces of the satellite that have broken off, the agency added.
It could take JAXA several months to find out enough about the satellite's condition to come up with ways to get it working again.
Hitomi is thought to have lost control of its stabilizing mechanism and begun to spin early on March 26, before parts broke off several hours later.
JAXA has not yet been able to re-establish the lost communication link, but has received four incomplete bursts of data, suggesting some of the satellite's functions are still working.
Hitomi, jointly developed by JAXA, the U.S. National Aeronautics and Space Administration, and other concerns, is equipped with four X-ray telescopes and two gamma-ray detectors.
Scientists hope its observations could shed light on the mysteries of black holes by measuring X-rays emitted from jets of gas pulled in by the holes' gravity.
Astronomy observations were scheduled to begin this summer following several months of calibration.
The satellite, dubbed the Astro-H before its launch, was sent into orbit on an H-2A rocket from a space center in southwestern Japan's Kagoshima Prefecture.
Quelle. Kyodo News
Elusive Japanese black hole seeking satellite breaks silence
Hitomi aims to investigate the formation and evolution of supermassive black holes at the centers of galaxies, and to unearth the physical laws governing extreme conditions in neutron stars and black holes.
Japan's X-Ray Astronomy Satellite Hitomi, which was launched last month, has managed to make fleeting contact with ground control amid reports that the spacecraft has separated into six parts.
The X-Ray Astronomy Satellite Hitomi, which was launched into low-Earth orbit from Japan's Tanegashima Space Center on February 17, has communicated sporadically with ground control in spite of reports that the satellite has separated into six parts.
Hitomi means "eye" in Japanese, specifically the eye's pupil. It was developed by JAXA to study energy processes in the universe.
The satellite's instruments enable high sensitivity observations of the universe across wide energy range, from X-rays to gamma-rays, in order to investigate the mechanisms of how galaxy clusters were formed and influenced by dark energy and dark matter.
Hitomi aims to investigate the formation and evolution of supermassive black holes at the centers of galaxies, and to unearth the physical laws governing extreme conditions in neutron stars and black holes.
On May 27, the Japan Aerospace Exploration Agency (JAXA) stated that scheduled communication with the satellite had failed on March 26. JAXA had not been able to figure out the state of health of the satellite.
JAXA said it had received a short signal from the satellite, and "is working on its recovery."
Amid fears that the satellite would not be able to fulfil its investigative mission, on March 29 JAXA announced that it had received two more short signals from the satellite, but had "not been able to find the state of its health."
The first was at about 10:00 a.m. on March 28 at Japan's Uchinoura Ground Station, and the second was at around 12:30 a.m. on March 29 at the Santiago Tracking Station in Chile.
JAXA also revealed the reason for the satellite's wayward communication: according to data from the US Joint Space Operations Center, the satellite had separated into six pieces when five objects fell off the spacecraft on March 26.
Astronomer Paul Maley in Arizona published a video online, which is believed to show the Hitomi satellite spinning in a freefall on March 28.
Despite the accident, scientists are hopeful that Hitomi is mostly intact and will still be able to contribute to science.
JAXA official Masaki Fujimoto told Spacenews that Hitomi's problems likely started with a loss of attitude control in the spacecraft, which stabilizes its
position in space. This disrupted the spacecraft's ability to generate power from its solar panels and communicate with the ground.
Officials said that in the absence of evidence that the spacecraft was struck by debris, it seems likely the spacecraft generated the debris itself.
"There's hope for recovery unless the spacecraft is severely damaged," Fujimoto said, but added that such a recovery would take months rather than days.
Space agency may give up on troubled Y31 bil X-ray satellite
Japan’s space agency may abandon the effort to re-establish communication with an X-ray astronomy satellite launched in February, a senior agency official says.
“We haven’t given up hope for recovery, but we may have to think about the worst-case scenario,” Saku Tsuneta, vice president of the Japan Aerospace Exploration Agency, told a press conference on Friday.
The Hitomi satellite, jointly developed by JAXA, the U.S. National Aeronautics and Space Administration and other concerns, is equipped with four X-ray telescopes and two gamma-ray detectors. Japan spent about 31 billion yen on its development.
It was expected to shed light on the mysteries of black holes by measuring X-rays emitted from jets of gas pulled in by the holes’ gravity.
Trouble communicating with Hitomi, meaning “pupil of the eye” in Japanese, began March 26 and JAXA completely lost contact with the satellite on March 29.
The trouble is believed to stem from broken attitude control devices, leading the satellite to spin once every five seconds. The fierce spinning apparently caused solar battery panel parts and other crucial components to break off.
The problems with Hitomi may also affect a plan to launch a different science satellite during the current fiscal year through next March, because it uses some of the same parts as Hitomi, according to JAXA.
If communication cannot be re-established with the satellite, it will become space junk and eventually burn up when it enters Earth’s atmosphere.
The satellite, dubbed the Astro-H before its launch, was sent into orbit by an H-2A rocket launched on Feb 17 from the Tanegashima Space Center in southwestern Japan’s Kagoshima Prefecture.
Quelle: JAPAN TODAY
Japan's X-ray satellite down for the count
TOKYO -- The Astro-H X-ray satellite has become inoperative since arriving in Earth orbit in February, potentially stalling some astronomy research until 2028.
Transmissions from the satellite, developed jointly by Japan, the U.S. and Europe, failed to begin as planned March 26. The satellite, also called Hitomi, has been mostly quiet since.
Visual observations from the University of Tokyo and other organizations show the device rotating once every five seconds or so, the Japan Aerospace Exploration Agency, or JAXA, said Friday. But the satellite is supposed to remain mostly still under ordinary circumstances.
The rotation may have separated solar cells and other equipment from the main body, the agency said, potentially impairing the satellite's functioning even if communication can be re-established. Hitomi's attitude control system, sensors and software are being investigated as causes.
JAXA launched the satellite in mid-February at the cost of 31 billion yen ($286 million). Hitomi is designed to make precise observations of X-rays from phenomena such as a black hole or supernova in order to advance understanding of the nature of the universe and our galaxy. The two other X-ray satellites in orbit are past their planned operational lives, and the next one is to be launched from Europe in 2028. Failure to recover Hitomi could create an observational gap sometime between now and then.
Students observe damaged Hitomi X-ray satellite and debris
Daytona Beach FL (SPX) Apr 20, 2016
The Hitomi satellite.
Engineering Physics students at Embry-Riddle Aeronautical University's Daytona Beach Campus have made several high-cadence telescope observations of the recently damaged Hitomi X-ray satellite and several of its debris pieces.
Hitomi, also known as ASTRO-H, was a Japanese X-ray astronomy satellite that was launched in February. The $275 million spacecraft was 46 feet long when deployed and weighed 6,000 lbs. It carried a number of scientific instruments, including a unique device called an X-ray microcalorimeter that was intended to investigate the evolution and large-scale structure of the universe, dark matter distribution, how matter behaves in high-gravity areas like black holes, and other high-energy phenomena.
It experienced a catastrophic event on March 26 during its first test observations 360 miles above the Earth. The U.S. Joint Space Operations Center detected several fragments of debris in the area and Hitomi's orbit suddenly changed.
"As soon as we got news of the suspected breakup, we wanted to observe the fragments with OSCOM, an optical tracking and spectral characterization system capable of observing large and small space objects, to see for ourselves how chaotically they were tumbling," said Forrest Gasdia, an Embry-Riddle graduate student in Engineering Physics. "As soon as the skies were clear, Sergei Bilardi [Engineering Physics undergraduate] and I deployed a telescope for the observations."
"The Physical Sciences Department has an impressive array of telescope assets, including a 1-meter (40-inch) Ritchey-Chretien reflecting telescope, and OSCOM, which was seed funded by a National Science Foundation grant," said Dr. Aroh Barjatya, associate professor and program coordinator of the Engineering Physics program at the Daytona Beach Campus.
"All of these assets are readily available for our students majoring in Engineering Physics, which has a strong emphasis on space systems engineering, as well as a new Astronomy and Astrophysics program."
Using OSCOM, the Engineering Physics students have obtained rapid brightness measurements of the satellite and debris fragments tumbling through space. These high-speed measurements - up to 100 samples per second for the main fragment - reveal bright reflections of solar light caused by different parts of Hitomi.
The data show a strong and consistent flash pattern with a period of 2.6 seconds. Further details about the OSCOM system, more photometry results, and observation videos can be found on the Space and Atmospheric Instrumentation Lab (SAIL) website.
Although OSCOM specializes in observing small satellites and CubeSats in low-Earth orbit (LEO), the project team has also developed optical observation and analysis techniques for solving space situational awareness problems with spatially resolved satellites in LEO, satellites in geostationary orbit, and debris and near-Earth asteroids.
Jaxa's litany of errors spun Hitomi to pieces
Agency releases analysis of why the satellite broke up
Japan's space agency Jaxa has detailed the litany of errors that ended with the failure of its Hitomi (Astro-H) spacecraft.
The agency has published a 90-page discussion of what caused the break-up.
Their conclusions are pretty damning for the agency, centring around a lack of protocols to manage a major change in the craft's thruster, and the disabling of safety systems.
The sequence of events before the break-up, as far as the analysis can determine, started with a problem in the attitude control system (ACS). This reported that the satellite was rotating when it wasn't, and to break the mistakenly-reported spin, mission controllers started the reaction wheel spinning.
The next failure was that the magnetic torquer operated by the ACS didn't work, and that caused the reaction wheel to keep accumulating angular momentum (in other words, speeding up).
This was exacerbated by a loss of Star Tracker (STT) data, which would have told the controllers the reported spin was incorrect; and even when the data was available, a misconfiguration meant it was ignored.
The ACS decided the satellite was in a critical situation, switched it to a safe mode, and tried to use the thrusters to correct things – but it used “inappropriate thruster control parameters”, and sped up the rotation. That resulted in the solar array paddles, the “extensible optical bench”, and other components breaking away.
There was yet another failsafe that wasn't operating. The satellite had a Coarse Sun Aspect Sensor, which again would have provided data contradicting that from the ACS. The designers had decided not to use this data, because the limited 20° field of view of the sensors risked it producing false positives.
The result, as Spaceflight 101 notes, was: “designers allowed one attitude measuring device overruling all other systems, introducing a single point of failure”.
Other failings detailed in the report include:
Thruster parameters that were inappropriate for the configuration after the 6.3 metre Extensible Optical Bench (EOB) was deployed;
A lack of documentation or operational plans to change the thruster parameters in the presence of the EOB;
Instructions were given to a third party company to change the thruster parameters, but as Spaceflight 101 puts it, “technical details on how the parameters were changed were not shared between that company and JAXA.”
The software used to generate thruster parameters, the RCS Drive Matrix Generation Tool, also lacked a user manual or operational training.
Quelle: The Register