A-Sat debris threat to ISS, says Nasa chief; experts rubbish claim
Times of India
April 03, 2019
Surendra Singh and Chidanand Rajghattta
Indian space and missile experts have rubbished the claims
of Nasa's chief, who on Monday
called India's anti-satellite (A-Sat) test a "terrible, terrible
thing" and said debris from the test could endanger astronauts aboard the
International Space Station (ISS).
In arguments reminiscent of the American reaction to
India's nuclear test, the US space agency bore down on India with a vehemence
not reflected in the more measured response from the Trump administration.
"That is a terrible, terrible thing to create an event that sends debris
at an apogee that goes above the International Space Station," Nasa
administrator Jim Bridenstine said at a townhall meeting of
the agency's employees.
Former DRDO director general V K Saraswat said the
statement was a typical American response to India's progress. "Pieces of
debris from the missile-satellite collision do not have enough velocity to
survive in space for long. The debris, generated at an altitude of 300km, will
ultimately fall and burn out in Earth's atmosphere," Saraswat told TOI.
Saraswat slammed Nasa for singling out India's A-Sat test
on the question of space debris.
"Lakhs and lakhs of space debris are already orbiting
in space. Aren't they posing a danger to ISS? Every year, 190 satellites of
varying sizes are launched into the low-earth orbit and this number is only
going to grow. Each satellite launch creates a lot of debris. So talking about
a little debris from India's test is meaningless," he said.
Bridenstine claimed that Nasa's analysis showed that the
threat to ISS from possible collisions had increased by 44%, without explaining
how he came up with the number.
"We are learning more and more every hour about
orbital debris created from this anti-satellite test. Where we were last week,
from an assessment that comes from Nasa experts... was that the risk to ISS was
increased by 44%. The risk, and I am talking about small debris impact to the
ISS, went up 44% over a period of 10 days," he said.
"We have identified 400 pieces of orbital debris from
that one event (the Indian test)," Bridenstine explained gravely.
"Now, all of it cannot be tracked. What we are tracking right now, objects
big enough to Indian space and missile experts have rubbished the claims
of Nasa's chief, who on Monday
called India's anti-satellite (A-Sat) test a "terrible, terrible
thing" and said debris from the test could endanger astronauts aboard the
International Space Station (ISS).
In arguments reminiscent of the American reaction to
India's nuclear test, the US space agency bore down on India with a vehemence
not reflected in the more measured response from the Trump administration.
"That is a terrible, terrible thing to create an event that sends debris
at an apogee that goes above the International Space Station," Nasa
administrator Jim Bridenstine said at a townhall meeting of
the agency's employees.
Former DRDO director general V K Saraswat said the
statement was a typical American response to India's progress. "Pieces of
debris from the missile-satellite collision do not have enough velocity to
survive in space for long. The debris, generated at an altitude of 300km, will
ultimately fall and burn out in Earth's atmosphere," Saraswat told TOI.
Saraswat slammed Nasa for singling out India's A-Sat test
on the question of
"Lakhs and lakhs of space debris are already orbiting
in space. Aren't they posing a danger to ISS? Every year, 190 satellites of
varying sizes are launched into the low-earth orbit and this number is only
going to grow. Each satellite launch creates a lot of debris. So talking about
a little debris from India's test is meaningless," he said.
Bridenstine claimed that Nasa's analysis showed that the
threat to ISS from possible collisions had increased by 44%, without explaining
how he came up with the number.
"We are learning more and more every hour about
orbital debris created from this anti-satellite test. Where we were last week,
from an assessment that comes from Nasa experts... was that the risk to ISS was
increased by 44%. The risk, and I am talking about small debris impact to the
ISS, went up 44% over a period of 10 days," he said.
"We have identified 400 pieces of orbital debris from
that one event (the Indian test)," Bridenstine explained gravely.
"Now, all of it cannot be tracked. What we are tracking right now, objects
big enough to track... 10cm or bigger... about 60 pieces have been tracked.
They have got tracking number... Out of those 60, we know that 24 of them are
going above the apogee of ISS."
India has questioned how 400 pieces of orbital debris
generated by the test posed a greater hazard than the tens of thousands of
fragments produced by US, Chinese and Russian tests.
Bridenstine, however, also acknowledged that the debris
from the Indian test was much smaller compared to that created by a similar
test by China in 2007, which generated thousands of pieces, and that no harm
was likely to be done to the ISS or the astronauts.
"While the risk went up 44%, our astronauts are still
safe. The ISS is still safe. If we need to manoeuvre it, we will. But the
probability of that, I think, is low," he said, adding, "The good
thing is that it is low enough and over time this will all dissipate. You go
back in time, 2007, (the) direct ascent anti-satellite test by the Chinese, a
lot of the debris is still in orbit."
The ISS orbits Earth at an orbit between 330 and 435km,
mostly well above the 300km altitude at which India conducted the A-Sat test on
March 27.
track... 10cm or bigger... about 60 pieces have been tracked.
They have got tracking number... Out of those 60, we know that 24 of them are
going above the apogee of ISS."
India has questioned how 400 pieces of orbital debris
generated by the test posed a greater hazard than the tens of thousands of
fragments produced by US, Chinese and Russian tests.
Bridenstine, however, also acknowledged that the debris
from the Indian test was much smaller compared to that created by a similar
test by China in 2007, which generated thousands of pieces, and that no harm
was likely to be done to the ISS or the astronauts.
"While the risk went up 44%, our astronauts are still
safe. The ISS is still safe. If we need to manoeuvre it, we will. But the
probability of that, I think, is low," he said, adding, "The good
thing is that it is low enough and over time this will all dissipate. You go
back in time, 2007, (the) direct ascent anti-satellite test by the Chinese, a
lot of the debris is still in orbit."
The ISS orbits Earth at an orbit between 330 and 435km,
mostly well above the 300km altitude at which India conducted the A-Sat test on
March 27.
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