SpaceX Schedules Three Launches in 13 Hours Monday

Three launches in 13 hours spread between all three operational Falcon 9 pads in the US.  

The mission getting the headlines is the first one, the Crew 6 mission at 1:45 AM Monday morning from LC-39A on the Kennedy Space center.  The manned launch is followed by Starlink Group 6-1 seven minutes short of 12 hours later at 1:38 PM from SLC-40, a few miles SSE of 39A.  The final launch of the day is another group of Starlink satellites, group 2-7, just short of an hour after group 6-1 at 2:31 PM - all of these times in EST.  That last launch is from Vandenberg Space Force Base in California, SLC-4 East. 

A new aspect of the Starlink launches is the headline of the second launch at 1:38 PM.  SpaceX has posted pictures and information saying this will be the first batch of "next version" Starlink satellites, called the V2 Mini.  Their Twitter posts add, “V2 minis include key technologies—such as more powerful phased array antennas and the use of E-band for backhaul—which will allow Starlink to provide ~4x more capacity per satellite than earlier iterations.”  E-band is an imprecise designation; it covers 60 to 90 GHz.  Atmospheric attenuation (loss of signal strength) is worst at 60 GHz and drops quite a bit by 80 GHz (see chart here, for example), which ordinarily means it's a good frequency band to use for satellite-to-satellite in space, not so much for downlink to the ground.  

There's a lot of interesting details about these satellites in the source article compiled by Teslarati from SpaceX and others.   

The satellites will operate under SpaceX’s Starlink Gen2 FCC license, which currently allows the company to launch up to 7,500 of a nominal 29,998 satellites. At the same time as it continues to fill out its smaller 4,408-satellite Starlink Gen1 constellation with smaller V1.5 satellites, SpaceX has already begun launching the same smaller V1.5 satellites under the Gen2 license.

Eventually, those smaller and less capable satellites will likely be replaced with larger V2 satellites, but SpaceX appears to have decided that quickly adding suboptimal capacity is better than waiting for an optimal solution. In theory, that optimal solution is larger Starlink V2 satellites. As discussed in a previous FCC filing, SpaceX intends to operate up to three different types of Starlink satellites in its Starlink Gen2 constellation. The first variant is likely identical to the roughly 305-kilogram (~673 lb) Starlink V1.5 satellites that make up most of its Starlink Gen1 constellation.

Meanwhile, SpaceX has already built and delivered dozens of full-size Starlink V2 satellites to Starbase, Texas. Those more optimal spacecraft reportedly weigh anywhere from 1.25-2 tons (2750-4400 lb) each, offer almost 10 times more bandwidth than V1.5 satellites, and are so large and ungainly that they can only be launched by SpaceX’s next-generation Starship rocket. Starship is substantially delayed, however, so SpaceX chose to develop a third Starlink satellite variant combining many of the full-size V2 benefits into a package that can be launched by SpaceX’s existing Falcon 9 rocket.

I think the bottom line is that while these heavier V2 Mini satellites reduce the number that a Falcon 9 can lift from the 57 of the version 1.5 satellites, down to 21 of the V2 Mini satellites, those V2 Minis will add ~50% more bandwidth than the V1.5 satellites it would have otherwise launched.

Another interesting upgrade is to the Hall thrusters for maneuvering on orbit.  SpaceX has announced they're switching from krypton gas in the thrusters to argon gas.  The savings from this small change appear to be enormous.

As a result, even if every Starlink V2 satellite needs an excessive 200 kilograms of argon, fueling its next constellation of almost 30,000 V2 satellites could cost SpaceX less than fueling 4000 V1 satellites.

 

EDIT 2/27/23 at 9:30 AM EST TO ADD:  The milestone of three launches fell apart early Monday morning, when the countdown to launch Crew-6 went into a hold at about T-2:30 before launch.  The issue was later said to be a ground system issue, not with the Falcon 9 itself.  The mission is currently scheduled for early Thursday morning, 12:34 AM EST, about an hour earlier than this morning's attempt.