- 3261 - SATELLITES - removed from orbit? “Astroscale” signed a $3.4 million with internet mega-constellation operator “OneWeb: to develop a commercial system for removing defunct satellites from orbit. The technology will enable removing multiple satellites one by one with a single deorbiting spacecraft.
----------------------------- 3261 - SATELLITES - removed from orbit?
- The spacecraft, called “ELSA-d”, has successfully captured a simulated piece of space junk, completing the first phase of a demonstration mission that could pave the way for a less cluttered future in orbit.
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- Launched on March 22, 2021, ELSA-d brought with it to orbit a 37-pound “cubesat” fitted with a magnetic docking plate. During the experiment on August 25, 2021, ground controllers remotely released a mechanical locking mechanism attaching the cubesat to the main 386-pound removal craft. The two satellites were still held together by the magnetic system, which is responsible for capturing the debris.
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- The cubesat was then released completely and recaptured before floating too far away from the main spacecraft. This maneuver was repeated several times. This short demonstration enabled the company “Astroscale” to test and calibrate rendezvous sensors, which enable safe approach and capture of floating objects.
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- The operation was managed from Astroscale's ground control center in Harwell, U.K. The ground control team had to rely on 16 ground stations located in 12 countries around the world to maintain constant contact with the spacecraft for up to 30 minutes at a time.
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- A typical low Earth orbit mission's connectivity ranges from 5-15 minutes, with 1 or 2 ground station providers in a couple of locations. ELSA-d is performing complex demonstrations that have never been done before, and we need a very reliable and unusually long chain of connectivity to provide a constant real-time data feed throughout the demonstrations.
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- ELSA-d will conduct additional tests and will see the small satellite drift farther away from the removal craft. First, the cubesat will move away but remain in a stable position. Next, the ground controllers will make it tumble, just like an uncontrolled piece of space junk would in space.
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- This experiment will allow Astroscale to simulate a realistic scenario in which the removal spacecraft would first have to inspect its target, analyze its motion and then approach it in the safest and most efficient way.
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- Since the launch of the first-ever satellite, the Soviet Union's Sputnik 1 in 1957, humankind has placed into orbit over 11,000 satellites. The number has been rising sharply in recent years due to the advent of cheaper smaller satellites and especially mega-constellations, such as “SpaceX's Starlink‘.
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- There are currently more than 7,000 satellites in orbit, but only about 3,400 of them are active. The rest are old defunct spacecraft that are frequently too high above Earth to be pulled down by its gravity and burn up in the atmosphere.
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- There are also countless pieces of space debris, fragments created by collisions and explosions. The European Space Agency (ESA) estimates that approximately 34,000 space debris pieces larger than 4 inches currently orbit Earth.
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- The number of fragments between 0.4 and 4 inches is believed to be around 900,000.
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- There could be a staggering 128 million objects between 0.04 and 0.4 inches in size.
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- Experts believe that removing satellites after their mission ends is key for maintaining a safe orbital environment.
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- In the late 1970s, NASA physicist Donald Kessler predicted that objects in space will at some point start colliding in an out-of-control way, each collision generating fragments that cause further and further collisions. Some experts believe that this collision cascade is already happening.
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- September 2, 2021 SATELLITES - removed from orbit? 3261
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