New Satellites, Old Satellite; New Mission, Old Mission

The first launch of calendar '24 is scheduled for Tuesday night from Vandenberg SFB in a three hour launch window that begins at 7:22PM PST - aka 10:22PM EST.  The launch, called Starlink group 7-9, includes the first batch of Starlink satellites with direct-to-cell phone capability.  

"This launch will include the first six Starlink satellites with Direct to Cell capabilities that will enable mobile network operators around the world to provide seamless global access to texting, calling, and browsing wherever you may be on land, lakes, or coastal waters," SpaceX wrote in a mission description.

The direct to cell phone or smart phone coverage was first agreed to between T-Mobile and SpaceX in August of 2022 in plan called "Coverage Above and Beyond" that Musk referred to as "a massive game changer" for the users.  

"I think this is really a massive game changer," Musk said. "In a nutshell, it's no more dead zones."

The current landscape features plenty of dead zones — remote regions far from cell towers where smartphone users can't get a signal. Indeed, there are about 500,000 square miles (1.3 million square kilometers) in the United States that aren't covered by any cellular network, [T-Mobile president and CEO Mike] Sievert said.

Perhaps most unusual of all, this mission will fly on the first mission of a new, unused, Falcon 9 booster.  The booster will be as new as the satellites its lifting.

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From the "things were really happening over the last two weeks" category, we learn that NASA's Juno probe that's orbiting Jupiter made the closest pass of its mission over Io, Jupiter's most volcanically active moon.

The spacecraft came to within 930 miles (1,500 km) of the surface of Io, a dense moon that is the fourth largest in the Solar System. Unlike a lot of moons around Jupiter and Saturn, which have surface ice or subsurface water, Io is a very dry world. It is also extremely geologically active. Io has more than 400 active volcanoes and is therefore an object of great interest to astronomers and planetary scientists.

Images from the December 30 flyby were posted by NASA over the New Year holiday weekend, and they provide some of the clearest views yet of this hell-hole world. The new data will help planetary scientists determine how often these volcanoes erupt and how this activity is connected to Jupiter's magnetosphere—Io is bathed in intense radiation from the gas-giant planet.

Juno arrived at the Jovian system in July 2016 and in its 56 flybys of Jupiter has never gotten this close to Io, coming only within "several thousand miles" of the moon.  Juno is programmed to make another close flyby of Io on Saturday February 3rd which will allow scientists to compare changes on the moon's surface over a short period of time. 

Surviving over seven years in the hostile environment around Juno is no small feat, and because of the radiation in the system all the electronics on the spacecraft need to be radiation hardened.  That doesn't eliminate damages, it pretty much simply slows the damage.   

"The cumulative effect of all that radiation has begun to show on JunoCam over the last few orbits," said Ed Hirst, project manager of Juno at NASA’s Jet Propulsion Laboratory in Southern California. "Pictures from the last flyby show a reduction in the imager’s dynamic range and the appearance of ‘striping’ noise. Our engineering team has been working on solutions to alleviate the radiation damage and to keep the imager going."

Juno image of Io from the December 30th flyby.  NASA/SWRI image

Eventually, the radiation wins and Juno will have to be abandoned.  Currently, the plan is for the mission to operate until September 2025.  At that point, the satellite will be steered into Jupiter's atmosphere so that it will burn up and be destroyed.