SpaceX Falcon 9 Block 5 - Starlink L10 + SkySat 19, 20 & 21 - Launched August 18, 2020
Screenshot from SpaceX Webcast of the launch of Starlink L10
Mission Rundown: SpaceX Falcon 9 Block 5
Starlink L10 + SkySat 19, 20 & 21
Written: July 21, 2021
Another three backpackers want a ride
SpaceX will launch 58 Starlink satellites and 3 SkySat Earth-Observation satellites on their Falcon 9 rocket launching at 10:31 EDT - 14:31 UTC on August 18, 2020, from Space Launch Complex 40 - SLC-40, at the Cape Canaveral Air Force Station, Florida. Starlink L10, is the tenth operational launch of SpaceX’s Starlink communication satellite constellation. This is the eleventh flight of Starlink “L0 - L10”.
This will be the 10th 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 634 km downrange aboard SpaceX’s autonomous spaceport drone ship. Starlink V1.0 L10 first stage booster B1049-6 is set to again land on ‘Of Course I Still Love You‘ around eight minutes after liftoff.
SpaceX will also attempt to recover both fairing halves with their humorously named fairing catcher vessels: ‘GO Ms. Tree‘ and ‘GO Ms. Chief.’
The booster supporting this mission, B1049 was the fourth Falcon 9 Block 5 built.
B1049 first flew with the Telstar 18V/Apstar-5C satellite on September 10, 2018. After launching Starlink V1.0 L10 the booster’s designation changed to B1049-6.
The static fire test for B1049 took place on August 17, 2020 at 06:00 EDT.
SpaceX is the first entity ever that recovers and reflies its fairings. The recovery vessels, Go Ms. Tree and Go Ms. Chief, will most likely attempt to recover the fairing halves. After being jettisoned, the two fairing halves will use cold gas thrusters to orientate themselves as they descend through the atmosphere. Once at a lower altitude, they will deploy drogue chutes and parafoils to help them glide down to a soft landing for recovery.
SpaceX is the first company to recover and reuse payload fairings. These are new Type 2.1 lifeboat sized fairings - 34 x 17 feet with 8 vents ports, a heat resistant thermal steel tip and no acoustic tiles inside the fairings.
This time the fairings are a reused pair from Starlink L3. Check out these recovery marks.
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 into a dispenser affixed to the second stage. The entire Starlink payload weighs around 15,600 kg. 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 eleven launches of one testbed Starlink mission and ten operational Starlink missions V0.9 L0 - V1.0 L10 brings the total number of launched operational Starlink satellites to 593. Prior to Tuesday’s launch of L10, it’s known that 4 operational Starlink satellites have destructively reentered as designed, after encountering issues after launch.
How many operational Starlink satellites that still work’s, or are in orbit, is no longer up to date. There is only this old article to go by. I don’t count the first 60 Starlink V0.9.
The fleet of test satellites which preceded the v1.0 design are also currently in the process of being deorbited for destructive reentries. The Tintin B satellite, one of two Tintin test satellites launched in 2018, reentered on August 8. Tintin A’s orbit is also decaying and expected to re-enter Earth’s atmosphere in the near future.
Of the 60 v0.9 satellites launched in 2019, four have reentered to date, with the remaining 56 either actively deorbiting or naturally decaying. The Tintin and v0.9 satellites will not be part of the operational Starlink satellite constellation.
SpaceX will assign 18-20 satellites to 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.
SkySat Earth Observation Satellite 19, 20 & 21
SkySat is a constellation of Earth observation satellites built by Maxar Technologies and operated by Planet Labs. There are currently 18 SkySats in a 500 km SSO. Each satellite is about an 80 cm large cube, with a mass of 120 kg. These satellites provide a resolution of less than a meter. The SkySat constellation is used to monitor the movement of goods and people, allowing for data to be gained and used to optimize supply chains, shipping, plant activity, and human relief efforts.
The SkySat satellites are built by Maxar Technologies, and are designed to capture high resolution panchromatic and multispectral images of Earth via the use of a 3.6 meter focal length Cassegrain telescope and three 5.5 megapixel CMOS (complementary metal oxide semiconductor) imaging detectors on each spacecraft, thereby enabling an image resolution of less than 50 centimeters. The SkySats are also outfitted with a modular propulsion system utilizing “green propellants”, which are intended to be less toxic and more efficient when used for in-space maneuvers.
Fifteen Planet SkySat satellites have been launched to date, with the first two spacecraft serving as prototypes. Both were launched in November 2013 and July 2014 as secondary payloads on Dnepr and Soyuz rockets, respectively.
The other thirteen operational satellites have been launched to 500 kilometer (310.6 mile) sun-synchronous orbits, having flown on ISRO’s Polar Satellite Launch Vehicle (PSLV), Arianespace’s Vega, Northrop Grumman’s Minotaur-C, and SpaceX’s Falcon 9 over a four-year period.
SpaceX has launched many satellites for Planet Lab over the years, with multiple Dove nanosatellites flying on Falcon 9 rockets and Dragon spacecraft, and two other SkySat spacecraft (SkySats 14 and 15) having launched on the SSO-A mission in December 2018.
SpaceX launched three SkySat spacecraft (SkySats 16, 17, and 18) on the Starlink V1.0 L8 mission, with another three satellites (SkySats 19, 20, and 21) scheduled to fly on Starlink L10 later in the year. These six satellites will complement the existing SkySat fleet in sun-synchronous orbit and offer more targeted coverage in key geographic regions.
Each operational SkySat spacecraft weighs around 110 kilograms (242.5 pounds) at liftoff. When combined with the mass of the 58 Starlink satellites that will fly on Saturday’s mission, the total launch mass rounds up to 15,410 kilograms (33,973 pounds), and then comes the mass of the dispenser systems for SkySat and Starlink satellites.
The three SkySat satellites were mounted on top of the Starlink payload stack during the V1.0 L10 mission, with a custom adapter provided by Planet Labs housing the trio until spacecraft separation.
SpaceX has also booked many customers for upcoming dedicated rideshare flights to Sun Synchronous Orbit, which will deploy at higher altitudes.
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 miniscule 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.
This batch of 58 Starlink satellites should be "VisorSat" fitted with the new sunshade to help reduce the brightness of the satellites as seen from the ground. These visors will deploy shortly after spacecraft separation during Saturday’s launch.
As was the case with a single Starlink satellite on the V1.0 L7 mission (launched on June 4), all Starlink satellites that will launch on subsequent missions “L8 - L10” going forward will feature a sun shade or visor, which will assist in blocking sunlight from reflecting off the majority of the spacecraft body while in orbit and reducing its overall albedo/intrinsic brightness as observed from the ground.
Starlink ground antennas
Prototypes of the Starlink user terminal antenna have been spotted alongside the other antennas at Starlink gateway locations in Boca Chica, Texas and Merrillan, Wisconsin. These user terminals will be crucial to the success of the Starlink network.
SpaceX board member Steve Jurvetson recently tweeted that the company’s board had an opportunity to try out the user terminals at the company headquarters in Hawthorne. The devices use a Power over Ethernet (PoE) cable for their power and data connection. The antenna connects to a SpaceX branded router with Wi-Fi (802.a/b/g/n/ac, transmitting at 2.4 & 5GHz). SpaceX is producing the antenna assemblies in-house while outsourcing production of the more common router component.
SpaceX continues to make progress setting up its network of 34 gateways for the Starlink system. New gateways are being added in the Northwest and North Central U.S. with locations in Northern California, Idaho, Minnesota, Montana, Washington, and Wyoming. In the Southeastern U.S. Previously filed gateways in Tennessee and Florida were removed while new gateway locations were added in Arizona, Georgia Kansas and Alabama.
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