Autor Wątek: [SN] NASA warns Indian anti-satellite test increased debris risk to ISS  (Przeczytany 320 razy)

0 użytkowników i 1 Gość przegląda ten wątek.

Offline Orionid

  • Weteran
  • *****
  • Wiadomości: 10237
  • Very easy - Harrison Schmitt
NASA warns Indian anti-satellite test increased debris risk to ISS
by Jeff Foust — April 2, 2019

The missile launched March 27 in India's anti-satellite test intercepted a satellite in a low orbit, but still created debris in orbits that go above the International Space Station. Credit: DRDO

WASHINGTON — In the sharpest rebuke to date by a U.S. government official, NASA Administrator Jim Bridenstine criticized India’s recent anti-satellite test April 1, saying it created debris that posed a threat to the International Space Station.

During a town hall meeting with NASA employees, Bridenstine was asked about the March 27 test, dubbed “Mission Shakti,” where a ground-launched missile struck the Microsat-R satellite in an orbit less than 300 kilometers high. The Indian government said the low altitude of the test minimized the amount of long-lived debris.

Bridenstine, though, said that the test did produce some debris placed into higher orbits, including those above that of the ISS, which orbits at an altitude of about 410 kilometers. He said 400 pieces of debris had been identified from the test, 60 of which are large enough to be tracked by U.S. military assets, such as radars.

“Of those 60, we know that 24 of them are going above the apogee of the International Space Station,” he said. “That is a terrible, terrible thing, to create an event that sends debris into an apogee that goes above the International Space Station. And that kind of activity is not compatible with the future of human spaceflight.”

“It’s unacceptable, and NASA needs to be very clear about what its impact to us is,” he continued. Experts from NASA and the military’s Combined Space Operations Center concluded last week that the risk of debris impacting the station increased by 44 percent over a 10-day period, he said, but didn’t specify the baseline risk level that was increased by that amount.

Bridenstine emphasized that, despite the increased risk, the six people currently on the station are not in danger. “While the risk went up 44 percent, our astronauts are still safe. The International Space Station is still safe,” he said. “If we need to maneuver it, we will. The probability of that, I think, is low.”

He suggested, though, that last week’s test was irresponsible and set a bad precedent. “When one country does it, then other countries have to feel like they have to do it as well,” he said.

Bridenstine’s statements represent the strongest criticism to date of the test by a U.S. government official. While Air Force officials confirmed they monitored the test and tracked debris from it, neither they nor the State Department spoke out as forcefully against the Indian ASAT test.

A State Department spokesperson, in a statement to SpaceNews April 1, offered only mild criticism of the test. “The United States recognizes, and encourages other nations to recognize, that orbital debris represents a growing threat to the space operations of all nations. We took note of Indian government statements that the test was conducted at a low altitude to limit the orbital lifetime of resulting debris,” the spokesperson said.

The lack of response from the U.S. government, until Bridenstine’s remarks, stood in contrast to criticism from a number of companies that operate in low Earth orbit. Those companies worry about how such tests could increase orbital debris and adversely affect their operations.

“While Planet enjoys a great working partnership with agencies of India’s government — like [the Indian space agency] ISRO — we categorically condemn the anti-satellite missile intercept recently conducted by India’s defense department,” said Planet, the company that operates a large constellation of low Earth orbit imaging satellites, in a March 27 statement.

Experts highlighted the differences between commercial and government responses to the test. “I think that speaks to the emerging power of the commercial sector as a player in influencing behavior in space,” said Brian Weeden, director of program planning at the Secure World Foundation, during a panel discussion by that organization March 29 on U.S.-China space relations.

He added, though, he was concerned about the precedent that the Indian test set. “Right now, it appears that the norm is that it’s okay to test that, as long as you try to minimize space debris,” he said. “I don’t think that’s a norm that we want to have, but that appears to be what the norm is.”

And companies have yet to back up their criticism of the Indian ASAT test with more concrete actions. While Planet condemned the test, it still launched 20 of its Dove satellites on an Indian Polar Satellite Launch Vehicle March 31.


Offline Orionid

  • Weteran
  • *****
  • Wiadomości: 10237
  • Very easy - Harrison Schmitt
Odp: [SN] NASA warns Indian anti-satellite test increased debris risk to ISS
« Odpowiedź #1 dnia: Kwiecień 10, 2019, 21:19 »
India ASAT debris spotted above 2,200 kilometers, will remain a year or more in orbit
by Caleb Henry — April 9, 2019 [SpaceNews]

Some debris from India's March 27 ASAT test will take over a year to deorbit. Credit: AGI

COLORADO SPRINGS — At least a dozen fragments from India’s March 27 anti-satellite test reached altitudes above 1,000 kilometers, meaning some debris will stay in orbit much longer than estimated by India, according to research from Analytical Graphics Inc. (AGI).

One fragment was spotted at 2,222 kilometers, nearly eight times higher than where India intercepted one of its own satellites with a ground-launched missile, Dan Oltrogge, a senior research astrodynamicist at AGI, said.

That fragment, and others orbiting at high altitudes in low Earth orbit, will remain in space much longer than the 45 days recently projected by India’s Defence Research and Development Organisation, Oltrogge said.

“Many fragments already reentered in the first one to two days, and then there’s quite a cluster that reenters between then and out to as much as one to two months,” Oltrogge said at the 35th Space Symposium here. “But there are some fragments that can go out one to two years.”

Two days after the March 27 test, the U.S. Air Force said it was tracking 250 pieces of debris created when India’s PDV-Mk II missile intercepted at 280 kilometers a satellite dubbed Microsat-R that India launched in January. On April 1, NASA Administrator Jim Bridenstine, lamenting an increased risk to the International Space Station, said that 400 pieces of debris were created.

Oltrogge, who runs AGI’s Center for Space Standards and Innovation, said no satellites are known to have been struck by debris from India’s ASAT test. He cautioned, though, that satellite operators may not disclose such information if there was a strike.

AGI data showed that multiple Russian Kanopus remote sensing satellites and Dove satellites operated by commercial company Planet were among 25 spacecraft most at risk of intersecting with debris paths from the ASAT test.

The European Space Agency’s Aeolus wind-mapping satellite, which launched in August, was also among the 25 most-at-risk satellites.

Oltrogge said AGI created that list based on “the risk that a fragment will be at the center of mass of the satellite.”

That risk isn’t exactly the same as hitting a satellite, because the probability of an impact also depends on the size of the satellite and the debris, he said.

The ISS, which orbits at roughly 410 kilometers, was among the top 60 spacecraft threatened by the debris, according to AGI.

“These high-apogee fragments are crossing satellites above them, including the ISS,” Oltrogge said. “These fragments, although there aren’t that many of them, do put other spacecraft at risk during the time they are up there.”


Offline Orionid

  • Weteran
  • *****
  • Wiadomości: 10237
  • Very easy - Harrison Schmitt
Odp: [SN] NASA warns Indian anti-satellite test increased debris risk to ISS
« Odpowiedź #2 dnia: Czerwiec 29, 2019, 08:01 »
Half of Indian Anti-Satellite Test Debris Still Orbiting in Space - Harvard Astronomer
by Staff Writers New Delhi (Sputnik) Jun 28, 2019

India's anti-satellite missile was a three-stage rocket, which successfully engaged an Indian orbiting target satellite on 27 March. The Indian defence ministry claims that the test was conducted to intercept the missile in a manner that minimised the threat of space debris.

Three months after India conducted an anti-satellite test in which it "shot down" a low-orbiting satellite, the 41 pieces of debris generated in the process remain in orbit. This accounts for about 50% of all fragments of debris that were created in the 'Mission Shakti' missile test, says Jonathan McDowell, an astronomer at the Harvard-Smithsonian Center for Astrophysics.

This is in complete contrast to the claim made by India's Defence Research and Development Organisation (DRDO) which said the test was planned in a manner to ensure that all debris would fully disintegrate within 45 days.

McDowell estimates that the debris will take "at least a year or so" to fully deteriorate. Another satellite tracker Marco Langbroek claimed that "many of these objects still on-orbit have apogees still well into the range of operational satellites, i.e. they remain a threat to other objects in space".

In his analysis published on 18 June, Langbroek warned that these remaining objects, "at least 5 objects will stay in orbit for at least a year to come, and the last one might not reenter until mid-2021".

Earlier in April, US space agency NASA called the destruction of Microsat-R satellite a "terrible, terrible thing" that poses a threat to astronauts aboard the International Space Station (ISS).

The Russian defence ministry raised similar concerns just after the test, and said that the over 100 fragments that were formed in the altitude range from 100 to 1,000 kilometres have been orbiting very close to the ISS, "which may create threats in the near future".

The US has criticised India over its anti-satellite missile test, calling it unacceptable and incompatible with the future of human space flight.

On 27 March, Indian Prime Minister Narendra Modi announced New Delhi had successfully tested its first anti-satellite missile by hitting a defunct Indian satellite at an altitude of 300 km. Modi added that India had become the fourth country in the world to possess such a weapon after China, Russia, and the United States.

Source: RIA Novosti