SpaceX Falcon 9 Block 5 - Starlink L06 - Launching April 22, 2020
Screenshot from SpaceX Webcast of the launch of Starlink L06
Mission Rundown: SpaceX Falcon 9 B5 - Starlink L06
Written: July 20, 2021
Geoff Barrett makes poster like Mission Views about Starlink L06, which is very informative
60 Starlink with dispenser weighs 18.5 ton
SpaceX’s Starlink L06 mission will launch 60 satellites on its Falcon 9 rocket. It’s expected to launch on April 22, 2020 from Launch Complex-39A - LC-39A at the Kennedy Space Center, Florida. The seventh flight “L0 - L06” Starlink launched 60 satellites Wednesday, 22 April at 15:30 EDT - 19:30 UTC.
This will be the 6th operational launch of SpaceX’s near-global satellite constellation – Starlink, which aims to deliver a fast, low-latency broadband internet service to locations where access has previously been unreliable, expensive, or completely unavailable.
After boosting the second stage along with its payload towards orbit, the first stage will perform an entry burn to slow the vehicle down in preparation for atmospheric reentry. The booster will then land 621 km downrange aboard SpaceX’s autonomous spaceport drone ship ‘Of Course I Still Love You.’ SpaceX will also attempt to recover both fairing halves with their humorously named fairing catcher vessels: ‘GO Ms. Tree‘ and ‘GO Ms. Chief.’
B1051 first flew the first Crew Dragon for SpaceX’s uncrewed DM-1 mission on March 2, 2019. B1051 launching Starlink V1.0 L06 will change its flight number to B1051-4.
To prepare for Wednesday’s launch, B1051 was successfully static fire tested at LC-39A on Friday, April 17, 2020.
Starlink V1.0 L06 is set to again land on Of Course I Still Love You 8 minutes after liftoff.
SpaceX is the first company to recover and reuse rocket fairings. One fairing segment on this mission is from the AMOS-17 mission from August 6, 2019. The recovery vessel Go Ms. Tree caught one fairing half out of the air with its nets. The second segment landed softly in the ocean and the recovery ship Go Navigator scooped it up. This will be the first launch that uses a fairing caught in the net.
The Payload
SpaceX plans to offer service in North America by the end of 2020 and estimates that once complete, its venture will make $30-50 billion annually. The funds from which will, in turn, be used to finance its ambitious Mars program.
To achieve initial coverage, SpaceX plans to form a net of 12,000 satellites, which will operate in conjunction with ground stations, akin to a mesh network.
Furthermore, the company recently filed for FCC permission on an additional 30,000 spacecraft, which, if granted, could see the constellation amount to a lucrative 42,000. This would octuple the number of operational satellites in earth orbit, further raising concerns about the constellations' effect on the night sky and earth-based astronomy.
For more information on Starlink, watch the Real Engineering video listed below.
Each Starlink satellite is a compact design that weighs 260 kg. SpaceX developed them to be a flat-panel design to fit as many satellites as possible within the Falcon 9’s 5.2 meter wide payload fairing. 60 satellites fit onto a dispenser plate affixed to the second stage.
The entire Starlink payload weighs around 15,600 kg and with the dispenser 2,900 kg system on the existing PAF on the second stage. That’s near the limit that a Falcon 9 can lift into LEO and still have enough propellant for landing.
For such small satellites, each one comes loaded with high-tech communications technology. There are six antennas, four high-powered phased-array and two parabolic ones that all support high-speed data throughput. Starlink also features a SpaceX built and designed star track navigation system to enable precision placement of broadband throughput.
Four inter-satellite laser links (ISLLs) allow high-speed communication between Starlink satellites. SpaceX placed two ISLLs on the front and rear of the satellite to talk with Starlink satellites in the same orbital plane. They remain fixed in position. Two ISLLs on the satellite’s sides track other Starlink satellites in different orbital planes. This means they have to move to track the other satellites.
The seven launches of one testbed Starlink mission and six operational Starlink missions V0.9 L0 - V1.0 L6 brings the total number of launched Starlink operational satellites to 360. How many operational satellites that still work’s, or are in orbit is no longer unknown.
SpaceX will assign 20 satellites to each of three orbital planes. Orbital planes are to satellites as tracks are to trains – they are orbits parallel to each other designed to maximize area coverage while minimizing the number of satellites required.
SpaceX plans to begin offering Starlink service to Canada and the northern United States later this year. Near global coverage is expected to start next year. Pricing has not been made public, but it has been hinted that speeds up to one gigabit may be possible.
Ion Drive with Krypton gas
Innovative ion propulsion technology keeps these satellites in the correct position while on orbit. They use ion Hall-effect thrusters to achieve their working orbit. Each Starlink satellite incorporates an autonomous collision avoidance system. It uses the Department of Defence’s debris tracking data to avoid colliding with space debris or other satellites.
Starlink’s low altitude also allows SpaceX to easily deorbit malfunctioning satellites, even if their engines fail. Although 100 km is commonly described as the upper limit of Earth’s atmosphere, there is no “hard barrier”. Even at 550 km altitude, there is still a slight amount of atmospheric drag pulling the satellites down. Each satellite’s onboard ion Hall-effect thruster engines is powerful enough to keep it in orbit, but if the engine fails, it will fall back to Earth within about a year.
The minuscule atmospheric drag in low Earth orbit will help ensure that dead satellites don’t stay in orbit for long. This will help reduce the amount of space debris in orbit, which is rapidly becoming a major concern.
Starlink Satellite Constellation
Constellations use multiple satellites working in conjunction for a common purpose. SpaceX plans eventually to form a network of about 12,000 satellites. They will operate roughly 4,400 satellites using Ku- and Ka-band radio spectrum, and almost another 7,500 satellites in the V-band.
To achieve initial coverage, Starlink will use 72 orbital planes, angled at 53 degrees from the Earth’s equator at an altitude of 550 km. They will put 22 satellites into each of these orbital planes, totalling 1,584 satellites. They will communicate with other Starlink satellites and with ground stations, akin to a mesh network.
In late 2019, the company asked the American Federal Communications Commission (FCC) for permission to launch an additional 30,000 satellites into orbits ranging from 328 km to 580 km in altitude. If the FCC okays the request, the constellation could grow to 42,000 satellites. This would increase the number of operational satellites in Earth orbit by at least a factor of 20 from pre-2019 levels.
The constellation’s large numbers are raising concerns regarding their effect on the night sky and Earth-based astronomy. However, Elon Musk stated that he is confident that SpaceX can mitigate light pollution issues and is working with industry experts to minimize the potential for any impact. Future Starlink satellites will use a sunshade that is a patio-like umbrella to reduce light reflectivity.
Note - The Reaction Control System - RCS thrusters have been renamed Attitude Control System - ACS thrusters both using pressurized cold Nitrogen gas stored inside the LOX tank in COPV Carbon Overwrapped Pressure Vessels or a heavy duty gas tank.
