Starlink 6 launching on a Falcon 9 rocket

Starlink 6 | Falcon 9 Block 5

What’s All This Mean?

SpaceX’s Starlink 6 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. Starlink 6, is the sixth operational launch of SpaceX’s Starlink communication satellite constellation.

Lift Off Time
(Subject to change)
April 22, 2020 – 19:30 UTC | 15:30 EDT
Mission Name and what it is
Starlink 6: the sixth Starlink v1.0 launch
Launch Provider
(What rocket company is launching it?)
SpaceX
Customer
(Who’s paying for this?)
SpaceX 
Rocket
Falcon 9-Block 5 B1051.4
Launch Location
Launch Complex-39A, Kennedy Space Center, Florida
Payload mass
18,500 kg (60 x 260 kg, plus dispenser) ~41,000 pounds
Where are the satellites going?
Low-Earth Orbit 550 km (Initially 210 x 366 km)
Will they be attempting to recover the first stage?
Yes 
Where will the first stage land?
About 630 km downrange on SpaceX’s drone ship Of Course I Still Love You.
Will they be attempting to recover the fairings?
SpaceX will attempt to recover both fairing halves
Are these fairings new?
No
This will be the:
  • 84th flight of a Falcon 9 (Atlas V is at 83 flights)
  • 51st booster landing
  • 35th re-flight of a booster
  • 3rd re-flight of a fairing
  • 1st re-flight of a caught fairing
  • 7th mission for SpaceX in 2020
Where to watch 
SpaceX Livestream

Tim Dodd, the Everyday Astronaut, will be streaming at T-30 minutes; come ask questions and join the conversation live!

If you are in the area, here’s where you can watch in person!

Graphic by Geoff Barrett Rocket by Stanley Creative

Starlink is SpaceX’s communications satellite division. Starlink’s satellite constellation will deliver a fast, low-latency broadband Internet service to locations where access is unreliable, expensive, or unavailable. SpaceX plans to offer service in the northern United States and Canada by the end of 2020. The company estimates that once complete, its venture will make $30-50 billion annually. The Starlink revenue, they hope, will help finance SpaceX’s ambitious human spaceflight Mars program.

Starlink satellites and dispenser.
Starlink satellites loaded into their dispenser, awaiting encapsulation into the Falcon 9’s payload fairing. Credit SpaceX.

Each Starlink version 1.0 satellite is a compact design that weights 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 weights 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.

Ion Power, Would Scotty be Impressed?

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, to maneuver while on-orbit and, at end of life, deorbit them. According to SpaceX, Starlink is the first krypton propelled spacecraft ever flown.

Becoming space junk is not in the cards for these satellites. 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. When they come to the end of their useful life, they will deorbit and completely burn up in the Earth’s atmosphere.

An image of the globe covered by Starlink orbital track tracings
Starlink covering the globe. Credit: SpaceX

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.

What is Falcon 9 Block 5?

SpaceX’s Falcon 9 rocket first flew in 2010. Since that time, 82 more launches occurred, with 80 of them being fully successful, one partially successful, and one in-flight failure. Starlink 6 will be the launch vehicle’s 84th flight. Over the years, it has gone through several upgrades and iterations, not including the Falcon Heavy. The current version is the Falcon 9 Block 5, introduced in 2018 and is now the main version in operation today.

The Block 5 is the final iteration of the Falcon 9 and rated to carry humans into space. Block 5’s goal was to apply all the lessons that SpaceX learned into a human-rated, reusable rocket, capable of sending Crew Dragon into orbit. Initially, Falcon 9 is Starlink’s primary carrier rocket, with Starship expected to supplant it.

Falcon 9 rocket launching a Starlink mission.
Falcon 9 rocket launching a Starlink mission. Credit: Tim Dodd, Everyday Astronaut.

Human-rating

The first change NASA required to human-rate the Falcon 9 was to put it into a design freeze. Before Block 5, no two Falcon 9s were the same, according to a SpaceX representative. Because of these continual improvements, NASA required SpaceX to fly seven missions in a row with no changes to the launch vehicle.

The second major change required the addition of a redesigned carbon over-wrapped pressure vessel (COPV). It was COPVs in the upper stage that caused the two previous Falcon 9 failures (AMOS-6 and CRS-7).

Reusability Tweaks

There were also many modifications in the Block 5 booster stage related to better reusability that were not critical for human-rating. SpaceX reinforced the landing legs, upgraded the grid fins, added a carbon fiber interstage, added a 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:

Tim Dodd, The Everyday Astronaut, explaining all the versions of the Falcon 9 rocket, from Version 1.0 to the Block 5. (Click on the image to watch the video)

Falcon 9 Booster Stage 1051

The booster supporting this mission is B1051. To prepare for Wednesday’s launch, it was successfully static fire tested at LC-39A on Friday, April 17, 2020. Previously,  this booster stage’s debut was on the first Crew Dragon mission called  SpaceX Demonstration Mission-1 (DM-1), on March 2, 2019. It’s second flight was Canada’s RADARSAT constellation mission, on June 12, 2019.  Finally, it flew on the third operational Starlink launch, on January 29, 2020. In conclusion, Starlink 6 will be its fourth flight and that changes the booster’s designation to 1051.4.

Fairing Reuse

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 this fairing 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 air.

A crane removes a fairing segment from SpaceX’s Go Navigator. Credit: Lupi.

After boosting the second stage along with its Starlink payload towards orbit, the first stage will perform an entry burn, to slow the vehicle down to prepare for atmospheric reentry. The booster will then land approximately 630 km downrange aboard SpaceX’s Autonomous Spaceport Done Ship (ASDS)  Of Course I Still Love You. SpaceX will also attempt to recover both fairing halves with their fairing-catcher vessels: Go Ms. Tree and Go Ms. Chief.

Countdown*

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

Launch, Landing, and Satellite Deployment**

Hr/Min/Sec              Event


00:01:14                    Max Q (moment of peak mechanical stress on the rocket)
00:02:33                   1st stage main engine cutoff (MECO)
00:02:36                   1st and 2nd stages separate
00:02:44                   2nd stage engine starts
00:03:24                   Fairing deployment
00:06:41                   1st stage entry burn complete
00:08:24                   1st stage landing
00:09:00                   2nd stage engine cutoff (SECO)
00:15:00                   Starlink satellites begin deployment

* Although Starlink’s launch window is officially instantaneous, previous Starlink missions had 90-minute launch windows.
** Times based on the most recent Starlink mission, Starlink 5.

Tim Dodd, the Everyday Astronaut, will stream this launch, starting at T-30 minutes. Come out to ask questions and join the conversation live! If you want the best way to know when a launch is happening, I suggest monitoring Prelaunch Previews and downloading the Next Spaceflight mobile app to stay in the know. Finally, if you would like to stay up to date with the activities of the SpaceX maritime fleet, go over to the SpaceX Fleet website that tracks the SpaceX ships that don’t go to space.

2 comments
  1. The Falcon family (Falcon 9 and Heavy) probably won’t (SpaceX is a U.S. company, and have 3 good launch pads), but the Starship might. Australia is a pretty good place to launch from, getting 3-ish degrees closer to the equator than Florida, and the West side is pretty clear of things boosters can land on (in the event of an RUD, of course). Besides, point-to-point transportation is supposed to go everywhere. I guess we’ll just have to wait and see where all Starship goes.

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