Starlink: Elon Musk minimizes the risk of orbital disorder posed by his satellites

The information site Space Daily posted a very interesting article that reports the point of view ofElon musk concerning the orbital disorder that could cause, therefore in the conditional, the satellites of the constellation starlink from SpaceX. In an interview with Financial Times, Elon Musk, never half-hearted, has responded to numerous allegations that satellites Starlink of his company occupy too much space on theorbit terrestrial, asserting that ” tens of billions ”Spacecraft could be in orbits close to Earth!

Musk explained that because space is ” simply extremely large “And that the satellites let him send ” are very small The situation is not as dire as it seems. ” This is not a situation where we are effectively blocking others in any way. We haven’t stopped anyone from doing anything, and we don’t intend to. “, he added. According to him, each orbital “shell” encircling the Earth is larger than the surface of the planet, with another shell every 10 meters or so farther into space, which he says would allow these ” tens of billions »Of satellites to revolve around the Earth with complete peace of mind. According to Elon Musk, there is enough room for tens of billions of satellites and ” a few thousand satellites, that’s nothing “.

This assertion by Musk has obviously been disputed by many scholars of management of the space traffic. According to Jonathan McDowell, astronomer at the Harvard-Smithsonian Center for Astrophysics (Massachusetts, United States), the satellites are ” moving at nearly 28,000 km / h need a lot more space to have time to change their orbits if a collision seems possible “. The expert calculated that at this speed, an interval of three seconds would only place about 1,000 satellites in each orbit.

Since it is complex to determine the trajectory of such a large number of distinct satellites relative to each other, and the variations in the weather report solar changes their trajectories, the risks of potential collisions are difficult to predict. And when this risk arises, which does not mean that a collision is certain but that two satellites threaten to pass each other only less than a kilometer away, there will come a day when it will be too late to carry out a maneuver of. avoidance.

Density of space traffic could prevent astronauts from living and working safely

But these are not the only issues that worry space agencies and space users. The mega-constellations that will eventually deploy with hundreds of thousands of small satellites by 2030 could seriously complicate human activity in low orbit.

By this horizon, in fact, it is estimated that there could be more or less 4,000 satellites which go up and down (end of life, failure, deorbitaiton). A chain of satellites that must be constantly monitored and avoided! Under these conditions, the probability of losing a active astronaut in the next ten years is a one in sixty chance!

In conclusion, and there everyone is united, it is quite simply a problem of traffic management and there is an urgent need to endow the space with a binding “traffic code”, capable of its own. alone to regulate space traffic. This is what the European Commission is proposing with the Spaceways project piloted by Telespazio.

Chinese space station forced to maneuver to avoid Starlink satellites

Article by Remy Decourt published on December 29, 2021

The chinese space station would have been forced to correct its trajectory twice in order to avoid a risk of collision with a satellite of the constellation SpaceX’s Starlink. A situation which shows the urgency of providing space with a “highway code” to manage space traffic, as the European Commission wishes with the Spaceways project.

In a document recently released by the UN Office for Outer Space Affairs in Vienna, China told the UN Secretary-General that on two occasions, satellites of the constellation starlink from SpaceX have ” consisting of dangers to the life or health of astronauts aboard the Chinese space station “. Chinese Foreign Ministry spokesman Zhao Lijian added another layer on Tuesday, noting that ” United States is ignoring its obligations under international treaties posing a serious threat to the lives and safety of astronauts “.

In other words, China accuses SpaceX of irresponsible and dangerous conduct in space and the United States of laxity in the management of its space activities. Charges that can make you smile when you know that the Chinese military is responsible for thousands of debris following a test of missile antisatellite produced in January 2007. Located at an altitude of some 800 kilometers, an out of service Chinese weather satellite was destroyed by a missile generating a profusion of debris which, for once, are much more dangerous than Starlink satellites because less predictable and maneuverable.

That said, it should not be denied that the hundreds of Starlink satellites already in orbit have increased the number of collision risks since the constellation began deployment. The Chinese space station, currently occupied by a crew of three taikonauts, which sits in a near-circular orbit at an altitude of about 390 kilometers with an orbit tilt of about 41.5 degrees, is no more exposed than other space users. In September 2019, theEuropean Space Agency had been forced to maneuver the Aeolus satellite to avoid a Starlink satellite. But as China knows how to make itself heard and respected, the controversy quickly swelled over the social networks Chinese.

It is therefore not surprising that, as China points out, two of them found themselves in July and October on a trajectory that could, in theory, cause them to collide with the Chinese space station. In theory, because we identify a risk of collision when a satellite can approach within a few kilometers of an object that it could strike. Strictly speaking, neither of the two Starlink satellites implicated by China was heading straight for the Chinese space station. However, this situation underlines the need to quickly set up a space traffic management system to regulate human activities in space. This is what the European Commission is proposing with the Spaceways project piloted by Telespazio.

Two collision risk avoidance maneuvers

Discover, below, the information relating to the two collision avoidance maneuvers carried out by the Chinese space station as presented by China to the United Nations Office for Outer Space Affairs.

As of April 19, 2020, the Starlink-1095 satellite has been moving stably in orbit at an average altitude of about 555 kilometers. Between May 16 and June 24, 2021, the Starlink-1095 satellite maneuvered continuously to an orbit of approximately 382 kilometers and then remained in that orbit. A rapprochement took place between the Starlink-1095 satellite and the Chinese space station on 1^er July 2021. For safety reasons, the Chinese space station took the initiative to perform an evasive maneuver on the evening of that day in order to prevent a potential collision between the two spacecraft.

The second collision avoidance was potentially more dangerous. On October 21, 2021, the Starlink-2305 satellite approached the Chinese space station. The satellite being in continuous maneuver, the maneuver strategy being unknown and the orbital errors being difficult to evaluate, there was therefore a risk of collision between the Starlink-2305 satellite and the Chinese space station. In order to ensure the safety and lives of the astronauts in orbit, the Chinese space station carried out a new evasive maneuver on the same day to prevent a potential collision between the two spacecraft.