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SpaceX wants to fly some internet satellites closer to Earth



SpaceX is revising its Internet initiative for satellites, Starlink, and now hopes to operate some of its spacecraft at a lower altitude than originally planned. In a new application to the Federal Communications Commission (FCC), SpaceX is asking the agency to change its license to operate more than 1,500 Starlink satellites at a height of 600 kilometers below its original desired business.

SpaceX argues that this change will make the space environment safer, as it will be easier to get rid of these satellites at this new altitude if they run out of fuel or if they can no longer function properly in orbit. This update may also explain the unexpected behavior of two Starlink SpaceX test satellites that have remained in lower orbit than expected.

Already in March, the FCC approved the SpaceX license for the first phase of the ambitious Starlink initiative ̵

1; the company's long-term plan to bring nearly 12,000 satellites into orbit, to transfer the Internet coverage to Earth. First, SpaceX asked the FCC for permission to place 4,425 satellites in orbit between 1,110 and 1,325 kilometers altitude. With this new application, SpaceX, however, requested that 1,584 of these satellites, which should be operated at 1,110 kilometers, instead be allowed to operate on 550 kilometers.

SpaceX says moving satellites to a lower altitude means they can do more with less. Originally, the company said it needed 1,600 satellites to operate at 1,110 kilometers, but if set lower, the company can achieve the same results with 16 fewer spacecraft. And the lower altitude makes it easy to dispose of these satellites once they're done in space. At this altitude, particles from the Earth's atmosphere bombard the spacecraft faster, pushing them out of orbit and pulling them onto the planet. And on the way down they burn in the atmosphere.


One of the SpaceX test satellites for Starlink, which was launched in February.
Image: YouTube / SpaceX

Getting these spacecraft out of orbit Timely manner is crucial as SpaceX plans to bring a large number of vehicles into orbit. A Starlink-sized constellation could dramatically increase the number of operational satellites in space, increasing the risk of collisions in space. A recent NASA study argued that 99 percent of these satellites must be reliably removed from orbit within five years of launch. Otherwise, the risk of satellite collisions increases significantly.

When orbiting a satellite, the vehicle is typically taken by engine to a sufficiently low altitude where the airborne particles and the earth's gravity pull the probe down so that it burns. With this new login, SpaceX 1.584 does not have to move its satellites significantly to get rid of them. The atmosphere at 550 kilometers should work within a few years. This is also helpful if the spacecraft fails in orbit. Satellites that fail at higher altitudes can turn into out-of-space space debris that remains in orbit for a long time. At lower altitudes, they can still fail, and the atmosphere will still swallow them in time.

the FCC, which expressed its concern about how reliable these satellites will be and whether they will be removed on time from orbit. When the FCC agreed with the Starlink initiative, the agency said, "It would be premature to approve SpaceX's proposal based on its current Debris orbit reduction plan." However, SpaceX received approval anyway, on the condition that the company would provide an updated plan on how to avoid its satellites in time.

The new application can also explain the behavior of two of the SpaceX test satellites currently in orbit. In February, SpaceX successfully launched a pair of test satellites – TinTin A and B – to test the technology required for the Internet from space. However, the satellites did not reach their final orbits in space. The aim was to introduce the satellites at an altitude of 511 kilometers. Once all the systems of the vehicles were checked, SpaceX would raise the pair with the engines aboard the satellites to a height of 1,125 kilometers. It would take about half a year. The company presented these plans in a letter to the FCC dated February 1, 2018, three weeks before launch


. This graph, created by Jonathan McDowell using data from Space_Track.org shows the orbital heights of TinTin A (red), TinTin B (blue), and the PAZ satellite (green) using the Starlink test satellites was started. Apart from a few minor maneuvers, the satellites have not substantially raised their orbits as originally planned.
Image: Jonathan McDowell

However, according to Space_Track.org, a site that uses satellites, the satellites have never left the vicinity of 515-kilometer tracking information from the US Department of Defense. A graph of the duo's position over time shows that the satellites in their orbit are naturally becoming deeper, most likely because the particles of the Earth's atmosphere pull them down, according to Jonathan McDowell, an astrophysicist at Harvard University who tracks spacecraft in orbit. In June and July, TinTin B slightly increased its orbit, suggesting a small combustion of the engines on board. TinTin A barely moved, except for a small push on October 17.

This led to speculation about a possible failure first reported in the Space Intel Report and SpaceX informed the site that the satellites "were brought into their intended orbit, communicating with ground stations continue with ground stations and are still in operation today. "

In today's FCC application, SpaceX says that it has decided to change orbits based on what it learned from the operation of TinTin A and B at the lower altitude. "Operating at a lower altitude offers several attractive features, both during nominal operation and in unplanned scenarios," SpaceX wrote in the clipboard. The company says it would simplify spacecraft design and reduce signal latency to just 15 milliseconds, which is "virtually imperceptible to almost all users," SpaceX said.

SpaceX admits, however, that the lower orbit has some disadvantages. As the atmosphere at this altitude is a bit denser, it also means that the spacecraft needs to work harder to stay in orbit and not be pulled prematurely onto the ground. This will also reduce the Earth's surface, which any satellite can cover at any given time. Therefore, SpaceX must change the way the spacecraft transmits its signals.

The FCC has yet to approve the request from SpaceX, but the commission has declared November "space moon", so it's likely that this will soon be on the move. In the meantime, SpaceX plans to launch its first Starlink satellite in 2019. Under the terms of its FCC license, SpaceX must launch at least half of its 4,425 satellites (possibly now 4,409) within six years to bring its satellites into full constellation. In October Reuters reported that SpaceX chief Elon Musk had reorganized the Starlink management to speed up program deadlines.


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