SpaceX readying for Sunday’s sixth Starlink launch, first fifth booster flight

Lead Image by Julia Bergeron

SpaceX is preparing its Falcon 9 to launch the Starlink V1.0 L5 mission, although the launch date has been moved to Sunday. This mission will be the first Starlink launch from LC-39A at Kennedy Space Center, and the first from the pad since the Crew Dragon In-Flight Abort Test in January 2020. The first stage is B1048.5 – marking the first time a Falcon 9 core flies for the fifth time. The launch is now scheduled for 9:22 AM Eastern on March 15.


This mission will launch the 5th batch of 60 fully-operational Starlink satellites – the sixth batch overall – to a Low Earth Orbit (LEO). This will also be the first Starlink launch from the historic Launch Complex 39A (LC-39A) at Kennedy Space Center. Previous Starlink missions launched from Space Launch Complex 40 (SLC-40), just over three miles south of LC-39A.

Now, as SpaceX starts ramping up the Starlink launch frequency, there may be a new bottleneck – launch pad availability.

LC-39A has been the sole starting point for Falcon Heavy and Crew Dragon missions. Those two capabilities make it unique among SpaceX’s launch pads, as the other two can only support uncrewed Falcon 9 rockets.

However, SpaceX is now starting to use LC-39A for commercial launches during downtime between Falcon Heavy and Crew Dragon launches. This will help relieve the new strain on SLC-40 from the increased Starlink launches, allowing for more time for refurbishment and launch preparations.

Starlink V1.0 L5 will be the first commercial Falcon 9 launch from LC-39A since the Es’hail-2 mission in November 2018.

This mission will launch the 5th batch of 60 fully-operational Starlink satellites – the sixth batch overall – to a Low Earth Orbit (LEO). This will also be the first Starlink launch from the historic Launch Complex 39A (LC-39A) at Kennedy Space Center. Previous Starlink missions launched from Space Launch Complex 40 (SLC-40), just over three miles south of LC-39A.

Now, as SpaceX starts ramping up the Starlink launch frequency, there may be a new bottleneck – launch pad availability.

LC-39A has been the sole starting point for Falcon Heavy and Crew Dragon missions. Those two capabilities make it unique among SpaceX’s launch pads, as the other two can only support uncrewed Falcon 9 rockets.

However, SpaceX is now starting to use LC-39A for commercial launches during downtime between Falcon Heavy and Crew Dragon launches. This will help relieve the new strain on SLC-40 from the increased Starlink launches, allowing for more time for refurbishment and launch preparations.

Starlink V1.0 L5 will be the first commercial Falcon 9 launch from LC-39A since the Es’hail-2 mission in November 2018.

The Falcon 9 rocket which will take V1.0 L5 to orbit contains the first stage core B1048.5.  The name “B1048.5” comes from SpaceX’s internal booster numbering scheme. The “B1” designates a first stage booster, “048” means it was the 48th first stage built, and “.5” means that the booster is configured for its fifth flight.

This launch is important for SpaceX, as it represents the first time a first stage launches for the fifth time. This is possible because of the upgraded Falcon 9 Block 5, which first flew in May 2018.

The Falcon 9 Block 5’s first stage was designed to perform 10 flights before major refurbishment is needed. SpaceX has not commented on how much, if any, refurbishment has actually been done between flights.

B1048 first flew in July 2018 on the Iridium NEXT-7 mission. It lifted off from SLC-4E at Vandenberg Air Force Base in California. It landed on the Autonomous Spaceport Drone Ship (ASDS) Just Read the Instructions, and was towed back to the Port of Los Angeles. B1048 flew for a second time three months later, carrying SAOCOM-1A from the same launch pad. This time, it landed on Landing Zone 4, located just a few hundred meters from SLC-4E.

For its third flight, it was transported via truck to Cape Canaveral. It launched from SLC-40, carrying Nusantara Satu and the Beresheet lunar lander to a geostationary transfer orbit. B1048 then landed on the ASDS Of Course I Still Love You.

B1048.4 launches the Nusantara Satu mission – via Mike Deep for NSF/L2

B1048 then launched the first operational Starlink mission – V1.0 L1 – from SLC-40 in November 2019. This flight was also the first to reuse a fairing half, which was recovered after the Arabsat-6A Falcon Heavy mission.

For Starlink V1.0 L5, it will again land on Of Course I Still Love You around eight minutes after liftoff. It will be towed back to Port Canaveral, then transported back to Cape Canaveral Air Force Station to be prepared for another flight.

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SpaceX is continuing to ramp the rate of Starlink launches as they work toward completing Phase 1 – a constellation of nearly 1600 satellites in a 550km-high orbit.

SpaceX will assign the satellites to one 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.

Another benefit of Starlink will be its low latency. Latency is the time it takes for a request to be sent from a router to a server, and vice versa. Generally, the lower the latency, the better. Elon Musk, the CEO of SpaceX, stated earlier this week that Starlink may have a sub-20 millisecond latency. This would put Starlink on-par with traditional cable internet.

Past and present satellite internet has been plagued with high latency. Often, this ranges from 400-600ms. This is because most internet satellites are located in geostationary orbit, nearly 36,000km above the Earth’s surface. The further away a satellite is, the longer it will take a signal to reach it.

Starlink is different because it orbits much closer to Earth, only 550km above its surface. The closer distance dramatically reduces travel time for signals, enabling a low latency.

Starlink’s low altitude also allows SpaceX to easily deorbit malfunctioning satellites, even if their engines fail. Although 100km is commonly described as the upper limit of Earth’s atmosphere, there is no “hard barrier”. Even at 550km up, there is still a slight amount of atmospheric drag pulling the satellites down. Each satellite’s onboard ion engine is powerful enough to keep it in orbit, but if the engine fails, it will fall back to Earth within about a year.

The atmospheric drag 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.

This Starlink mission is the only one expected to launch in March. The next will likely launch in April from SLC-40.

SpaceX hopes to launch two batches of satellites per month this year.39AFalcon 9ReusabilityStarlink

written by Ian Atkinson

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