SpaceX conducted its third orbital launch this month, as well as the 37th Falcon 9 and the company’s 39th overall orbital launch for 2023, with Falcon 9 B1073-9 launching on Monday, June 12 at 3:10 AM EDT (07:10 UTC) from Space Launch Complex 40 at the Cape Canaveral Space Force Station. The flight took a southeast trajectory through the pre-dawn darkness, with Just Read the Instructions 636 kilometers out in the Atlantic for landing support.
Starlink and other constellations’ impact on astronomy was discussed at last week’s American Astronomical Society (AAS) 242 conference in Albuquerque, New Mexico.
The flight had been scheduled for last week but had to be pushed back several times. Just Read the Instructions was returning with B1078-3 after it flew the Starlink 6-4 mission, and it docked at Port Canaveral on Tuesday, June 6. The drone ship sailed back out into the Atlantic for Starlink 5-11 support the following evening of Wednesday, June 7.
The drone ship needed to be turned around for this flight, which had been scheduled for Saturday, June 10 before being pushed back to Sunday and then to Monday. Drone ship turnaround is becoming a limiting factor in launch cadence, and flights – CRS-28 being the latest example – are being scrubbed now if the recovery conditions do not allow for a safe booster landing.
B1073 started its flying career in May 2022 with the Starlink 4-15 mission. Since then, the veteran booster has flown SES-22, Starlink missions 4-26, 4-35, and 6-2, along with the ill-fated Hakuto-R Mission 1 lunar lander, Amazonas Nexus, and Cargo Dragon C209 on CRS-27.
The payload of 52 Starlink satellites was launched into a 299 by 339-kilometer parking orbit at an inclination of 43 degrees. The satellites will be maneuvered, using Hall-effect krypton thrusters, to their operational circular orbit at 530 kilometers altitude during the coming months.
Group 5 uses the v1.5 satellites as part of the second-generation Starlink constellation, and each satellite now masses around 300 kg after the addition of inter-spacecraft laser links. There are now over 4,000 Starlink satellites in orbit, including several hundred satellites in Group 5.
While the Starlink constellation continues to be built up, concerns continue to be raised about mega-constellations’ impact on ground — and even space — based astronomy. The issue was discussed last week at AAS 242 in New Mexico, the second of the biannual yearly conferences held by the AAS.
One thing that was revealed during the conference was that satellite streaks in the Hubble Space Telescope’s field of view – and percentage of affected exposures – have doubled in 20 years, but that the brightness of these streaks has not increased. The vast majority of science observations with Hubble were not affected by these streaks.
The Starlink satellites orbit between 530 – 570 kilometers depending on which group they are in, and the Hubble Telescope orbits at roughly 535 kilometers altitude as of October 2022, as per NASA. Therefore, a number of Starlink satellites can appear in Hubble’s field of view.
Another megaconstellation’s currently orbiting satellites – OneWeb’s – orbit at even higher altitudes than Starlink so they can also appear in the veteran observatory’s field of view. Amazon’s Kuiper and China’s national broadband megaconstellation are in the works for the future as well.
SpaceX and OneWeb have both now signed a coordination agreement with the National Science Foundation to limit their megaconstellations’ impact on astronomy. SpaceX has taken various steps to limit their satellites’ brightness and has worked with the astronomical community on this issue.
While the Starlink constellation is being built up, the service continues to add capability. Starlink can now be used in moving environments, as demonstrated by children now able to listen to lessons and to do homework while on long school bus rides in Coconino County, Arizona.
In addition, Starlink was used to transmit data from the Starship test flight in April. Starlink set altitude and speed records for in-flight usage, enabling connectivity from as high as 123,600 feet and at a speed of Mach 1.7. Although not traveling quite as fast as Starship, airliners and private jets are also getting Starlink coverage to enable high-speed connectivity for passengers.
After this flight, B1073’s next flight after Starlink 5-11 will be as a Falcon Heavy side booster for the EchoStar-24 flight this coming August. SpaceX is working toward a goal of 100 orbital flights this year, with boosters now cleared for up to 20 flights each, if used on Starlink missions, as of last month.
(Lead image: Falcon 9 launches with Starlink satellites atop SLC-40.)