Starlink 19 | Falcon 9 Block 5

Lift Off Time	February 16, 2021 – 03:59 UTC February 15, 2021 – 22:59 EST
Mission Name	Starlink v1.0 L19 (Starlink RF Mission 2-1): the 19th Starlink mission
Launch Provider (What rocket company launched it?)	SpaceX
Customer (Who paid for this?)	SpaceX
Rocket	Falcon 9 Block 5 B1059-6; 59 day turn around
Launch Location	Space Launch Complex 40 (SLC-40), Cape Canaveral Space Force Station, Florida, USA
Payload mass	15,600 kg (~34,000 lbs) (60 x 260 kg, plus dispenser)
Where did the satellites go?	550 km circular Low-Earth Orbit (LEO)
Did they attempt to recover the first stage?	Yes
Where did the first stage land?	The first stage failed to land 633 km downrange on Of Course I Still Love You, and instead exploded near OCISLY Tug: Hawk; Support: GO Quest
Did they attempt to recover the fairings?	The active fairing half was successfully recovered, passive half damaged
Were the fairings new?	Yes, both the active half and passive half were new
This was the:	– 5th flight with relocation of fairing vents – 108th Falcon 9 launch – 54th re-flight of a booster – 3rd 6th flight of a booster – 5th re-flight of a booster in 2021 – 44th landing attempt on OCISLY – 5th launch for SpaceX in 2021 – 1st SpaceX launch on February 16 – 65th SpaceX launch from SLC-40 – 13th orbital launch attempt of 2021
Where to watch	Official livestream

How did it go?

SpaceX successfully launched their Starlink V1.0 L19 (Starlink 19) mission with 60 Starlink satellites atop its Falcon 9 rocket. The Falcon 9 lifted off from Space Launch Complex 40 (SLC-40), at Cape Canaveral Space Force Station, in Florida. Starlink 19 marked the 18th operational Starlink mission, boosting the total number of Starlink satellites launched to 1,145.

While the primary mission was successful, B1059-6 failed to land on Of Course I Still Love You due to the first stage under performing. Out of an abundance of caution, SpaceX then temporarily grounded the Falcon 9 fleet, for mission assurance.

What is Starlink?

Starlink is SpaceX’s internet communication satellite constellation. The Low-Earth orbit constellation will deliver fast, low-latency internet service to locations where ground-based internet is unreliable, unavailable, or expensive. 

Starlink is currently in the “Better Than Nothing Beta,” allowing anyone in approved regions to order or preorder. However, for now, only higher latitudes are fully covered, so people of lower latitudes are currently only able to pre-order Starlink. After 24 launches SpaceX will achieve global coverage, but the constellation will not be complete until ~42,000 satellites are in orbit. Given SpaceX’s current Starlink production and launch rate, Starlink will have global coverage, excluding the poles, by the middle of 2021.

Once Starlink is complete, the venture is expected to profit $30-50 billion annually. This profit will largely finance SpaceX’s ambitious Starship program, as well as Mars Base Alpha.

What is the Starlink Satellite?

Each Starlink V1.0 satellite has a compact design and a mass of 260 kg. SpaceX developed a flat-panel design, allowing them to fit as many satellites as possible into the Falcon 9’s 5.2 meter wide payload fairing. Due to this flat design, SpaceX is able to fit up to 60 Starlink satellites and the payload dispenser into the second stage, while still being able to recover the first stage. This is near the recoverable Falcon 9’s payload capacity to LEO, at around 17 tonnes. 

For how small each Starlink satellite is, each one is packed with high-tech communication and cost-saving technology. Each Starlink satellite is equipped with 4 phased array antennas, for high bandwidth and low-latency communication, and two parabolic antennas. The satellites also include a star tracker, which provides the satellite with attitude data, ensuring precision in broadband communication. 

The Starlink satellites are also equipped with an autonomous collision avoidance system, which utilizes the DOD’s debris tracking database to autonomously avoid collisions with other spacecraft and space junk. 

Currently, the Starlink satellites being launched into polar orbit have a laser communication system on board. This system is currently in version 0.9, however SpaceX is expecting all new Starlink satellites to be equipped with it by next year.

To decrease costs, each satellite only has a single solar panel, which simplifies the manufacturing process. To further cut costs, Starlink’s propulsion system, an ion thruster, uses krypton as fuel, instead of xenon. While the specific impulse (ISP) of krypton is significantly lower than xenon’s, it is far cheaper, which further decreases the satellite’s manufacturing cost.

Ion Power

Each Starlink satellite is equipped with the first Hall-effect krypton powered ion thruster. This thruster is used both for ensuring the correct orbital position, but is also used for orbit raising and orbit lowering. At the end of the satellite’s life, this thruster is used to deorbit the satellite.

What is the Starlink Satellite Constellation?

A satellite constellation is a group of satellites that work in conjunction for a common purpose. Currently, SpaceX plans to form a network of roughly 12,000 satellites; however, in 2019 SpaceX filed an application with the Federal Communication Commission (FCC) for permission to launch and operate an additional 30,000 satellites. These additional satellites would be placed in orbits ranging from 328 km to 580 km, which would further decrease latency, and increase the bandwidth. To put this number of satellites into perspective, this is roughly 20 times more satellites than were launched before 2019. 

Of the initial 12,000 satellites, 4,400 would operate on the Ku and Ka bands, with the other 7,600 operating on the V-Band. 

To achieve initial coverage, SpaceX will use 72 orbital planes, in a 53 degree 550 km circular orbit. The Starlink satellites will then communicate with other Starlink satellites and ground stations, to form a mesh network. 

Due to the vast number of Starlink satellites, many astronomers are concerned about their effect on the night sky. However, SpaceX is working with the astronomy community and implementing changes to the satellites to make them harder to see from the ground and less obtrusive to the night sky. SpaceX has changed how the satellites raise their orbits and, starting on Starlink V1.0 L9, added a sunshade to reduce light reflectivity. These changes have already significantly decreased the effect of Starlink on the night sky.

What is Falcon 9 Block 5?

The Falcon 9 Block 5 is SpaceX’s partially reusable two-stage medium-lift launch vehicle. Block 5 is the final iteration of the Falcon 9; the goal is to apply all the lessons learned from 56 previous Falcon 9 pre-Block 5 flights into a human-rated reusable rocket. The Falcon 9 contains 3 main components: a reusable first stage, an expendable second stage, and a reusable fairing.

Block 5 updates:

SpaceX introduced a lot of changes on Block 5, allowing it to become the crew-launching reusable rocket that we know today. To start, the Composite Overwrapped Pressure Vessels (COPVs) had to undergo a complete redesign. NASA mandated the COPV redesign, as it had been the cause of both of the Falcon 9 failures: AMOS-6 and CRS-7.

Alongside with certification for human spaceflight, Block 5 came with a number of other major changes. To increase the amount of flight each booster could handle, and decrease the turnaround time, SpaceX reinforced the landing legs, upgraded the grid fins, and added a carbon fiber interstage. They also added heat-resistant external paint and upgraded the engines. For more information about the changes in Block 5, and the other Blocks of the Falcon 9, check out this video by the Everyday Astronaut:

Falcon 9 Booster B1059

The booster that supported Starlink 19 is B1059. The booster flew for a total of 6 times. Its maiden flight was launching the CRS-19 mission, which launched on December 5th, 2019. The booster’s second flight was launching the final first generation Cargo Dragon, CRS-20, which launched on March 7, 2020. B1059 then launched the Starlink V1.0 L8 mission on June 13, 2020 and the SAOCOM-1B mission on August 30, 2020. The booster’s second to last launch was on the NROL-108 mission, which launch on December 19th, 2020. As Starlink 19 was the booster’s sixth and final flight, its designation will change to B1059-6.

Following stage separation, the Falcon 9 conducted 2 burns. These burns were not nominal, and the booster failed to land on Of Course I Still Love You.

Falcon 9 Fairings

The Falcon 9’s fairing consists of two dissimilar reusable halves. The first half (the half that faces away from the transport erector) is called the active half, and houses the pneumatics for the separation system. The other fairing half is called the passive half. As the name implies, this half plays a purely passive role in the fairing separation process, as it relies on the pneumatics from the active half.

Both fairing halves are equipped with cold gas thrusters and a parafoil which are used to softly touch down the fairing half in the ocean (or, occasionally in GO Ms. Tree’s or GO Ms. Chief’s net). On Starlink 19, SpaceX successfully recovered the active fairing half, but the passive half was damaged.

SpaceX is currently flying two slightly different versions of the Falcon 9 fairing. The new “upgraded” version has vents only at the top of each fairing half, by the gap between the halves, whereas the old version had vents placed spread equidistantly around the base of the fairing. Moving the vents decreases the chance of water getting into the fairing, making the chance of a successful scoop significantly higher.

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Starlink 19 Full Mission Profile

Hr/Min/Sec              Event

– 00:38:00                 SpaceX Launch Director verifies go for propellant load.
– 00:35:00                 RP-1 (rocket grade kerosene) loading underway.
– 00:35:00                 1st stage LOX (liquid oxygen) loading underway
– 00:16:00                 2nd stage LOX loading underway
– 00:07:00                 Falcon 9 begins engine chill prior to launch
– 00:01:00                 Command flight computer to begin final prelaunch checks
– 00:01:00                 Propellant tank pressurization to flight pressure begins
– 00:00:45                 SpaceX Launch Director verifies go for launch
– 00:00:03                 Engine controller commands engine ignition sequence to start
– 00:00:00                 Falcon 9 Liftoff

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Launch, Landing, and Satellite Deployment*

Hr/Min/Sec              Event

00:01:12                   Max Q (moment of peak mechanical stress on the rocket)
00:02:32                   1st stage main engine cutoff (MECO)
00:02:36                   1st and 2nd stages separate
00:02:44                   2nd stage engine starts (SES-1)
00:03:09                   Fairing deployment
00:06:41                   1st stage entry burn complete
00:08:24                   1st stage landing
00:08:47                   2nd stage engine cutoff (SECO-1)
00:45:31                   2nd stage engine starts (SES-2)
00:45:32                   2nd stage engine cutoff (SECO-2)
01:04:28                   Starlink 19 payload deploy

* All times are approximate