Since I was a young child Mars held a special fascination for me. It was so close and yet so faraway. I have never doubted that it once had advanced life and still has remnants of that life now. I am a dedicated member of the Mars Society,Norcal Mars Society National Space Society, Planetary Society, And the SETI Institute. I am a supporter of Explore Mars, Inc. I'm a great admirer of Elon Musk and SpaceX. I have a strong feeling that Space X will send a human to Mars first.
Tuesday, March 5, 2024
A North Korean Satellite Starts Showing Signs of Life
Malligyong
Kim Jong Un and his daughter visiting a Malligyong assemblage facility in May 2023. A Malligyong satellite (or mock-up thereof) can be seen in the background (credit: KCNA)
A North Korean satellite starts showing signs of life
by Marco Langbroek
Monday, March 4, 2024
Bookmark and Share
Three and a half months ago, on November 21, 2023, North Korea launched its first military reconnaissance satellite, Malligyong 1. A Chollima-1 rocket launched from Sohae inserted Malligyong-1 (international designator: 2023-179A) into a Sun-synchronous orbit of 512 by 493 kilometers and an inclination of 97.4 degrees. Within days of the launch, North Korea claimed that the satellite is taking imagery of targets of interest. But as was the case with its two “civilian” predecessors, Kwangmyŏngsŏng 3-2 and Kwangmyŏngsŏng 4, suggestions have been made by western sources that the satellite, although it successfully reached orbit, was nevertheless non-functional. As recently as a February 26 press conference, South-Korean Defense minister Shin Won-sik still maintained that “it is not showing any signs of performing tasks or engaging in reconnaissance activities.”
That remark did not age well, and it looks like Shin Won-sik’s staff had not kept him well informed in the days leading up to the press conference. Because a week earlier, starting on February 19, Malligyong-1 had started to show some unambiguous signs of life. Between February 19 and February 24, it performed five consecutive small orbit raising maneuvers, one each day, as shown by tracking data from the US military space tracking network CSpOC.
diagram
A diagram showing the evolution of apogee and perigee altitudes for Malligyong-1 since launch late November 2023, based on US tracking data. Note the stepwise raise in perigee altitude on the right in the diagram.
The series of small maneuvers raised the perigee altitude (the lowest point in its elliptical orbit) by nine kilometers, from 488 to 497 kilometers. In the process, it also circularized the orbit, reducing the orbital eccentricity to half the former value. The net effect was that the average orbital altitude was raised to 503 kilometers, the initial value from November 2023, correcting for all orbital altitude lost since then, and that the daily precession of the ascending node (which had been slightly growing over time) was reduced to a value closer to the ideal value of 0.986 degrees/day, in order to preserve the Sun-synchronous character of the orbit. The latter is important for an optical reconnaissance satellite: Sun-synchronous basically means that the satellite will pass over a certain spot on Earth at roughly the same time each day, which makes it more easy to compare images taken on different days for any changes in the surveyed areas.
diagram
A diagram showing the change in average orbital altitude. The orbit raise late February brought the orbital altitude back to its original value of 503 kilometers.
diagram
A diagram showing the rate of RAAN (ascending node) precession. The orbit raise and circularization late February lowered the rate to a value closer to the ideal sun-synchronous value of 0.986 deg/day.
Malligyong-1 maneuvering to raise its orbit is kind of a big deal. First, it shows that the satellite is not “dead,” unlike some western sources suggested, but functional—with the caveat that we do not know whether the onboard camera is actually taking images. Second, it underlines that the North Koreans have clear control over the satellite, including its attitude, and can modify its orbit. While this in and of itself might not seem to be a big feat, it is for North Korea, and pushes back against western efforts to downplay the technological advances North Korea is making in its space program.
It seems counterintuitive that a country, impoverished to the point where its citizens go without electricity and lack food, can build and launch functioning satellites, but clearly North Korea can.
A third implication of the demonstrated capacity to maneuver is that North Korea can now actively prolong the orbital lifetime of their satellites by doing periodic orbit raises. Their previous two satellites, KMS 3-2 and KMS 4, had an orbital lifetime of 12 and 8 years, respectively: due to natural orbital decay, their orbital altitudes progressively got lower and lower until the satellites both reentered into the atmosphere in 2023. With Malligyong-1’s capacity to raise its orbit, they can now postpone that process, and prolong operational value at an operationally meaningful altitude, as long as the satellite has fuel left on board.
This is the first time that a North Korean satellite has shown the ability to do orbital maneuvers, and to many analysts (including me) this ability comes as a bit of a surprise. It serves as a warning and wakeup call. There is a tendency among certain western pundits to routinely underestimate the technological level of North Korea’s ballistic missile and satellite programs. It seems counterintuitive that a country, impoverished to the point where its citizens go without electricity and lack food, can build and launch functioning satellites, but clearly North Korea can. To North Korea’s leadership, the missile and space program is vital for regime survival and hence gets a strong priority in funding.
Marco Langbroek is a satellite tracker from the Netherlands, and Lecturer in Space Situational Awareness at Delft Technical University. He can be reached at sattrackcam@langbroek.org.
Subscribe to:
Post Comments (Atom)
No comments:
Post a Comment