After a couple of delays, SpaceX announced a new target date to conduct the tenth Starlink mission which will also deploy a pair of BlackSky satellites under the company’s SmallSat Rideshare Program. This week on July 8, SpaceX was scheduled to deploy its tenth cluster of internet-beaming satellites into low Earth orbit, but the launch was postponed due to weather conditions at Florida’s coast. – “SpaceX is standing down from today's launch of its tenth Starlink mission due to weather conditions,” the company announced. It is the second time this mission is postponed. The mission was previously scheduled for June 26, SpaceX said the launch was delayed because “team needed additional time for pre-launch checkouts” and representatives stated, “Falcon 9 and the satellites are healthy.”
The four-times-flown Falcon 9 is waiting on Launch Pad 39A at NASA’s Kennedy Space Center in Cape Canaveral, Florida. The U.S. Space Force 45th Weather Squadron assesses weather conditions and sets a new target date to conduct the tenth Starlink mission. Today, July 9, SpaceX announced the new launch date – “Targeting Saturday, July 11 at 10:54 a.m. EDT for Falcon 9 launch of 57 Starlink satellites and 2 BlackSky spacecraft, a Spaceflight Inc. customer.” The U.S. Space Force predicts 60% favorable weather conditions for Saturday morning for the ten-minute launch window.
Targeting Saturday, July 11 at 10:54 a.m. EDT for Falcon 9 launch of 57 Starlink satellites and 2 BlackSky spacecraft, a @SpaceflightInc customer— SpaceX (@SpaceX) July 9, 2020
The pair of BlackSky satellites, that will ride alongside the Starlink batch, are Earth-observation satellites. –“In addition to the tenth batch of Starlink broadband satellites, we’re excited to take BlackSky’s 5th and 6th Earth observation microsatellites to orbit,” Spaceflight Inc. wrote in a press release. “We are happy to help BlackSky execute their long-term goal of operating a 60-satellite constellation whose goal is to shorten revisit times to 10 to 15 minutes, and sharpen resolution to under one meter.”
This Starlink mission will be special, because the entire fleet of 57 satellites feature ‘VisorSat’, a deployable visor that will act as a sunshade to reduce the satellite’s reflectivity. Starlink satellites look like a fleet of white lights flying in a train-like formation soon after deployment. The astronomer community voiced their concerns over Starlink possibly interfering with their cosmic observations. “SpaceX is launching Starlink to provide high-speed, low-latency broadband connectivity across the globe, including to locations where internet has traditionally been too expensive, unreliable, or entirely unavailable,” the company wrote. “We also firmly believe in the importance of a natural night sky for all of us to enjoy, which is why we have been working with leading astronomers around the world to better understand the specifics of their observations and engineering changes we can make to reduce satellite brightness.” SpaceX stated:
“All Starlink satellites on this flight are equipped with a deployable visor to block sunlight from hitting the brightest spots of the spacecraft – a measure SpaceX has taken as part of our work with leading astronomical groups to mitigate satellite reflectivity.”
The company previously deployed an experimental ‘DarkSat,’ which is a satellite featuring a dark anti-reflective coating that covered the most reflective parts of the satellite. DarkSat decreased the satellite’s visibility but a dark coating can cause thermal changes that can affect the satellite’s internet-beaming performance. Therefore, SpaceX engineers developed VisorSat and deployed an experimental version on a previous mission. VisorSat sunshades are made up of a radio-transparent foam material used to minimize the potential for reflection on the satellites' chassis where the antennas are located. “The key to making Starlink darker is to prevent sunlight from illuminating these white surfaces and scattering via reflection toward observers on the ground,” SpaceX explained, “Satellites are visible from the ground at sunrise or sunset. This happens because the satellites are illuminated by the Sun but people or telescopes on the ground are in the dark. These conditions only happen for a fraction of Starlink's 90-minute orbit.”
The tenth cluster of Starlink satellites will be deployed in a circular orbit. After deployment, the satellites use their onboard ion thrusters to raise into a higher orbit. These batch of satellites are expected to operate at an altitude of approximately 550-kilometers above Earth.
There's a total of 540 Starlink satellites in low Earth orbit right now. SpaceX aims to conduct at least one or two missions per month, to achieve rolling out Starlink internet service in northern portions of the United States and Canada before the end of this year. Company officials said 800 satellites will offer "moderate" internet coverage; 60 Starlink satellites can provide service to 40,000 customers. Ultimately, the Starlink network will consist of over 12,000 internet-beaming satellites in order to offer service globally.