Kessler Syndrome, orbital conjunctions and coping with the hazard of space debris

While there are numerous ongoing initiatives out there looking for a solution, it sounds like the problem may be just about to get a whole lot worse.

'For the second time in 2020, space boffins are warning of a potential collision in low-Earth orbit which could create thousands of pieces of shrapnel, threatening satellites, communications and future manned missions.

'Space debris-tracking service LeoLabs has sounded the alarm over a discarded Chinese rocket stage and a defunct Russian military satellite from the last millennium, which will come dangerously close to each other in the early hours of Friday. Their close flyby will see them come within 12 meters (40 feet) of each other on October 16, 2020 at 00:56 UTC. According to current calculations, there is a greater than 10 percent chance of impact at an altitude of 991km over the Weddell Sea off the Antarctic Peninsula.

'The pair have a combined mass of about 2,800kg and a relative velocity of 14.7 kilometers per second or 52,920 kph (A bullet travels at 2,736kph). The Chinese Long March 4B rocket was launched on May 10, 1999 while the defunct Russian Parus military satellite dates as far back as February 22, 1989, and was used primarily for communication and navigation. The Parus satellite has a 17-meter (56-foot) boom which adds an additional collision risk factor to the situation. To make matters worse, neither object can be maneuvered from the ground as they are both inoperable space junk.

'The current potential satellite colliders pose no risk to people down here on Earth, but could pose a major threat to operational satellites and assorted spacecraft in orbit. While collisions have accounted for less than one percent of fragmentation events in orbit in the last ten years, the legitimate concern is that, once enough space junk becomes stuck in orbit, it's only a matter of time before a runaway cascade effect occurs, creating a vast debris cloud which could render large swathes of low-Earth orbit useless to humankind.'


 
Are there any physicists on Arrse who understand orbital decay, and if a reduction in mass causes an exponential decay in orbit and subsequent burn up?

If two big heavy things collide, some of the total kinetic energy is converted to other forms as the structures are damaged/blown apart. As the subsequent pieces will be travelling more slowly, I assume that they will move to a lower orbit or burn up?
 

Yokel

LE
Are there any physicists on Arrse who understand orbital decay, and if a reduction in mass causes an exponential decay in orbit and subsequent burn up?

If two big heavy things collide, some of the total kinetic energy is converted to other forms as the structures are damaged/blown apart. As the subsequent pieces will be travelling more slowly, I assume that they will move to a lower orbit or burn up?

Orbital height is related to speed - it has nothing to do with mass. The problem with a collision that that debris would get thrown off in all directions and much of it would be to small to track. I think NORAD say they can only track things of 10cm across or larger.

There was an idea that SSTL were working on to harpoon derelict satellites and pull them out of orbit
 
Looks like a very lucky, very near miss! Kessler's prediction is getting closer to fact.

The unidentified object was seen in the path of the SpaceX rocket. Credit: SpaceX

The unidentified object was seen in the path of the SpaceX rocket. Credit: SpaceXSource:Supplied

'Incredible footage has shown a “UFO” narrowly missing the SpaceX rocket on its way to the Space Station - just hours before the astronauts on board were told to brace for a crash in a second near-miss.

'The “space debris” can be seen as it flies past the shuttle just 12 minutes into its mission, but six hours later, the four astronauts on board were told to buckle up when a second unknown object hurtled towards them.

'The first incident came after Crew Dragons launched from the Falcon 9 rocket’s second stage, as debris from the front capsule broke off and was propelled back to the craft. The piece, shown in the dramatic clip, shoots to the right and then pings back, missing the craft by seconds.

'But then at 1.43pm ET, around six and a half hours later, the crew were alerted to a second “unknown object” heading straight for them. The announcement came 20 minutes before the possible collision, forcing the crew to strap into their seats, with no time to perform an avoidance manoeuvre.

'Instead, the astronauts on board SpaceX’s recycled Crew Dragon capsule, the Endeavour, were told to put on their pressurised suits, reports Futurism. “The NASA/SpaceX team was informed of the possible conjunction by US Space Command,” NASA spokesman Kelly Humphries said. “The object being tracked is classified as ‘unknown’.'


 
With the Russian ASAT launch this week, and the large debris hazard it has created in LEO, pictures like the one above may become far more common for the ISS and any other manned-space vehicle.
 

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