Last week, Indian Prime Minister Narendra Modi said the country’s space agency had tested a new anti-satellite weapon by destroying a satellite already in orbit. Now, an announcement by NASA Administrator Jim Bridenstine claims that India’s test could endanger other satellites and objects in orbit—including the International Space Station.
India launched a missile at a satellite believed to be the Indian spy satellite Microsat-r, launched a few months ago. The blowup created a field of satellite debris at that altitude. That debris is a problem because it sits at the same altitude as the ISS. In a worst-case scenario, some of that debris could impact the station creating a Gravity-esque scenario. Some of those pieces are too small for NASA to track, meaning we’ll have no way of predicting an impact beforehand.
“What we are tracking right now, objects big enough to track — we’re talking about 10 cm (4 inches) or bigger —about 60 pieces have been tracked,” Bridenstine said in an announcement on Monday.
India deliberately targeted a satellite that orbited at a lower altitude than the ISS to prevent this sort of situation, but some of the debris appears to have reached higher. Of those 60 debris objects tracked by NASA, Bridenstine says 24 of them are at the same altitude as the ISS or higher.
The nature of low Earth orbit means that even debris pieces residing above the ISS could still pose a threat. Satellites and debris are gradually slowed by the very thin atmosphere that resides there. The ISS, for instance, routinely has to fire its boosters to increase its altitude to counteract atmospheric drag.
Those small debris pieces will lose altitude over time and eventually burn up in the atmosphere, but the high-altitude debris will have to come in range of the ISS before that happens. That means an impact could happen even a few months from now as high-altitude debris continues to fall.
The head of the United States’ National Aeronautics and Space Administration (NASA), Jim Bridenstine, on Tuesday branded India’s destruction of one of its satellites a “terrible thing” that had created 400 pieces of orbital debris and led to new dangers for astronauts aboard the International Space Station (ISS).
Mr. Bridenstine was addressing employees of the NASA five days after India shot down a low-orbiting satellite in a missile test to prove it was among the world’s advanced space powers.
Not all of the pieces were big enough to track, Mr. Bridenstine explained. “What we are tracking right now, objects big enough to track — we’re talking about 10 cm [six inches] or bigger — about 60 pieces have been tracked.”
The Indian satellite was destroyed at a relatively low altitude of 300 km, well below the ISS and most satellites in orbit.
But 24 of the pieces “are going above the apogee of the ISS,” said Mr. Bridenstine.
“That is a terrible, terrible thing to create an event that sends debris at an apogee that goes above the International Space Station. 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 said.
But the risk will dissipate over time as much of the debris will burn up as it enters the atmosphere.
The U.S. military tracks objects in space to predict the collision risk of the ISS and satellites.
They are currently tracking 23,000 objects larger than 10 cm.
Chinese test created 3,000 debris
That includes about 10,000 pieces of space debris, of which nearly 3,000 were created by a single event: a Chinese anti-satellite test in 2007 at 530 miles from the surface.
As a result of the Indian test, the risk of collision with the ISS has increased by 44 percent over 10 days, Mr. Bridenstine said.
Soon after the ASAT test, India said it was done in the lower atmosphere to ensure that there is no space debris. “Whatever debris that is generated will decay and fall back onto the earth within weeks.”
By conducting the test, the Ministry of External Affairs in New Delhi said, India was not in violation of any international law or treaty to which it is a party to or any national obligation.
Interestingly, Bridenstine is the first top official from the Trump administration to come out in public against the India’s ASAT test.
A day after India successfully carried out its ASAT test, acting US defence secretary Patrick Shanahan warned that the event could create a “mess” in space but said Washington was still studying the impact.
Bridenstine said the NASA is “learning more and more every hour” that goes by about this orbital debris field that has been created from the anti-satellite test.
“Where we were last week with an assessment that comes from NASA experts as well as the Joint Space Operations Center (part of US Strategic Command).. is that the risk to the International Space Station has increased by 44 per cent,” Bridenstine said.
“We are charged with commercialising of low earth orbit. We are charged with enabling more activities in space than we’ve ever seen before for the purpose of benefiting the human condition, whether it’s pharmaceuticals or printing human organs in 3D to save lives here on earth or manufacturing capabilities in space that you’re not able to do in a gravity well,” he said.
“All of those are placed at risk when these kinds of events happen,” Bridenstine said as he feared India’s ASAT test could risk proliferation of such activities by other countries.
“When one country does it, other countries feel like they have to do it as well,” he said.
“It’s unacceptable. The NASA needs to be very clear about what its impact to us is,” he said.
Risk gone up 44% over 10 days
The risk from small debris as a result of the ASAT test to the ISS went up 44 per cent over a period of 10 days. “So, the good thing is it’s low enough in earth orbit that over time this will all dissipate,” he told his NASA colleagues.
The ISS is a habitable artificial satellite, orbiting the Earth at an altitude between 330 and 435 km. It is a joint project between space agencies of US, Russia, Japan, Europe and Canada, and serves as a research laboratory for scientists to conduct space experiments.
As many as 236 astronauts from 18 countries have visited the space station, many of them multiple times, since November 2000.
Bridenstine said a lot of debris from the 2007 direct ascent anti-satellite test by China is still in the space.
“And we’re still dealing with it. We are still, we as a nation are responsible for doing space situational awareness and space traffic management, conjunction analysis for the entire world,” the NASA chief said.
“The International Space Station is still safe. If we need to manoeuvre it, we will. The probability of that I think is low. But at the end of the day we have to be clear also that these activities are not sustainable or compatible with human spaceflight,” he said.