SpaceX launches 60 Starlink satellites
CAPE CANAVERAL, Fla. — SpaceX made history again by launching the first 60 satellites of its Starlink satellite internet mega constellation.
The satellites launched at 10:30 p.m. May 23 (02:30 GMT May 24), 2019, atop a Falcon 9 rocket from Space Launch Complex 40 at Cape Canaveral Air Force Station in Florida. The spacecraft were deployed in orbit about an hour later.
Starlink is designed to provide high-speed, low-latency internet from space to entire planet, with a focus on areas with limited or no connectivity. While ultimately planned to include upward of 12,000 satellites, an initial operational constellation is expected to include just over 400 spacecraft, according to SpaceX CEO Elon Musk.
Musk said significant coverage would likely require 12 launches of 60 satellites. Each satellite is 500 pounds (227 kilograms).
However, while SpaceX said these first 60 spacecraft are production design, they a still testing a lot of new technology and future launches will hinge on how this first batch handles.
“There’s a lot of fundamental goodness about Starlink,” Musk said in a media teleconference on May 15. “We just want to make sure the appropriate caveats are there. There’s a lot of technology, this is very hard, and quite frankly in the past, the success of low-Earth orbit communications constellations, I believe none have successfully gone into operation without going bankrupt.”
Indeed SpaceX appears to be taking all the time they need. The company first tried to launch the satellites atop a previously-flown Falcon 9 rocket on May 15. However, high upper level winds caused the attempt to be scrubbed within minutes of liftoff.
The next day, the company was expected to try again, but decided against it hours before the planned liftoff time in order to “update satellite software and triple-check everything again.”
For the May 23 countdown, everything went smoothly. Even weather wasn’t an issue this time with the 45th Space Wing predicting a 90% chance of favorable conditions with the only concern being liftoff winds. However, those remained in check as the time of liftoff neared.
About 35 minutes before liftoff, SpaceX began fueling the 229-foot (70-meter) tall, two stage Falcon 9 with rocket grade kerosene and liquid oxygen. This fueling would last until the final minutes of the countdown.
Some 45 seconds before liftoff, with the tanks pressurized to flight levels, SpaceX’s launch director verified the Falcon 9 was go for launch.
Three seconds before liftoff, the nine Merlin 1D engines on the first stage of the Falcon 9 ignited and began spooling up to flight power. Once the countdown reached zero, the rocket was released from its launch mount and began rising toward space.
As the full rocket began accelerating higher and faster, the vehicle reached maximum dynamic pressure—the moment of peak mechanical stress exerted on the rocket from the atmosphere—about 1 minute, 13 seconds after liftoff.
Just over a minute later, at a mission elapsed time of roughly 2.5 minutes, the first stage’s nine engines finished their job and quit firing.
In a quick succession of events lasting than 10 seconds, the first and second stages separated, the second stage’s lone Merlin Vacuum engine ignited and the first stage began slowly pitching around 180 degrees to prepare for a landing on a drone ship in the Atlantic Ocean.
The second stage continued firing its engine all the way to orbit, cutting off some 8 minutes, 46 seconds after leaving Florida. During that ascent, at 3 minutes, 33 seconds, the payload fairing protecting the 60 Starlink satellites from Earth’s lower atmosphere separated since it was no longer needed, saving weight.
While the second stage was traveling spaceward, the first stage continued on its trajectory earthward, culminating in a landing on the drone ship named “Of Course I Still Love You,” situated some 385 miles (620 kilometers) downrange. That successful touchdown took place at about 8.5 minutes after liftoff.
Meanwhile, in orbit, the second stage and the Starlink satellites coasted for nearly 40 minutes before a brief engine restart of about three seconds finalized the spacecrafts’ deployment orbit of about 273 miles (440 kilometers), inclined about 53 degrees from the equator.
Then, about an hour after liftoff, the second stage, which was purposefully put into an end-over-end spin, deployed the 60 Starlink satellites using the rotational force from the spin to fan out the spacecraft similar to, as SpaceX described it, spreading out a deck of cards on a table.
The deployment occurred in an instant, but it took time for each satellite to slowly move away from each other. It was possible that some spacecraft brushed up against each other during separation, however, SpaceX designed the satellites to be able to withstand any minor impact.
Over the coming days, weeks and months, the Starlink satellites will use onboard krypton-fueled ion propulsion to increase their orbit to a final altitude of 340 miles (550 kilometers) with the spacecraft spreading out over the orbital plane.
Each satellite is a flat-panel design with multiple high-throughput antennas, according to SpaceX, and includes a single solar array. All told, the company said about 95% of these spacecrafts’ components are designed to burn up in earth’s atmosphere at the end of its design life. Future Starlink satellite iterations are “moving to complete disintegration.”
Additionally, each Starlink satellite is capable of tracking on-orbit debris and autonomously avoid potential collisions, SpaceX said.
Once the satellites technology is verified, SpaceX plans to launch more, with up to seven 60-satellite batches in 2019 alone.
The first phase of Starlink is expected to involve some 1,600 satellites in 40 orbital planes at this altitude. A second phase will see as many as 2,800 spacecraft at around 710 miles (1,150 kilometers).
Finally, a third phase is expected to include 7,500 satellites in a very low Earth orbit of only 210 miles (340 kilometers). For comparison, the International Space Station orbits at about 250 miles (400 kilometers).
These low altitudes not only mean low-latency connections, but safety should a satellite become defunct before being deorbited as an uncontrolled spacecraft won’t stay in orbit for more than several years before falling back into the atmosphere.
This launch was the sixth SpaceX mission of 2019 and the fifth for a Falcon 9. Overall, the rocket design has flown 71 times since 2010. Since December 2015, a total of 40 first stage boosters have successfully landed, including those from Falcon Heavy missions.
SpaceX’s next Falcon 9 launch is set to send the three-satellite RADARSAT constellation into orbit for the Canadian Space Agency. It is slated to fly no earlier than June 11 from Space Launch Complex 4E at Vandenberg Air Force Base in California.
Video courtesy of SpaceX
Derek Richardson has a degree in mass media, with an emphasis in contemporary journalism, from Washburn University in Topeka, Kansas. While at Washburn, he was the managing editor of the student run newspaper, the Washburn Review. He also has a blog about the International Space Station, called Orbital Velocity.