SpaceX launched the ninth batch of version 1.0 Starlink satellites from Kennedy Space Center in Florida on August 7 at 5:12 am UTC using a five-time flight-proven first stage.

A total of 59 satellites — 57 Starlink and 2 BlackSky — were launched over the course of a flight lasting more than 90 minutes, with a number of extended coast phases between second stage separation and engine firings. Normally, Starlink is able to deploy without a second stage firing, but the passenger satellites needed a bit of extra help to circularize their orbit. Unlike Starlink, the BlackSky sats have no primary propulsion system which means they are not able to adjust their orbit.

BlackSky satellites Global-7 and Global-8 each have a mass of about 55 kg and required a separate deployment mechanism. These two join four others already in orbit and are intended to be a part of a 16-member constellation that is planned to be replaced every three years or so using ride-share agreements like the one made for this launch.  A full constellation of sixteen satellites will allow the hourly imaging of most major cities on Earth.

Starlink satellites individually have a mass of about 250 kg. They’re packed into the fairing like a deck of playing cards and are launched all at once by releasing a single tension rod that holds them in place. This compact setup is why two BlackSky satellites took up three Starlink slots, even though the combined mass of the BlackSky sats is less than a single Starlink.

All of the Starlink satellites on this launch were VisorSats — the newest Starlink configuration intended to decrease the reflectivity of the satellites. Previous Starlink satellites were brighter than expected, with magnitudes of up to 2.5 or brighter, before dropping to 4th or 5th magnitude once at their operating altitudes. 

The controversy, of course, is that the eventual number of Starlink satellites in orbit is planned to be in the thousands to tens of thousands, and the existing satellites have already caused problems for astronomers, professional and amateur alike. Trains of bright Starlink satellites have affected data collection and deep-sky astrophotography sessions by leaving streaks across the images. Early observations of a beta VisorSat launched in early June of this year suggest that the VisorSats will be much dimmer even before migrating to their final orbits at about 550 km altitude, which should mitigate many of the complaints from the observing community. 

The first stage was successfully recovered by the Of Course I Still Love You barge, which was the second time SpaceX has successfully landed a five-times reused booster. Unfortunately, Ms. Tree & Ms. Chief were unable to catch the fairing halves in their nets, but they were recovered from the ocean.

More Information

BlackSky article 

Spaceflightnow article