Roamy here. There might be a weather delay, but there’s a 70% chance that the Juno spacecraft will be launched at 11:34 AM Eastern time today. The launcher is an Atlas V.
An interesting fact about Juno is that it does not use a plutonium thermoelectric generator for power, as did previous missions to the outer planets. Florida Today said:
Bruce Gagnon, coordinator of the Global Network Against Weapons & Nuclear Power in Space, has previously protested nuclear power’s use, noting, “It is quite interesting that NASA is going to use solar to travel to Jupiter — they once claimed it was impossible. I think it just goes to show you that they needlessly put people and the planet in grave danger during past plutonium launches.”
Those past plutonium launches they protested included the Galileo and Ulysses probes in 1989 and 1990. There’s a lot of things that were impossible 22 years ago that aren’t now. Solar cell efficiency has been steadily increasing, along with our understanding of radiation effects on new solar cell types such as triple junction. Jupiter is 5.2 times farther away from the sun than the Earth, so it gets about 4% of our solar energy. Jupiter also has radiation belts which make the engineering that much more challenging. I took part in testing the solar cells used on Juno, understanding how much performance would be lost due to the radiation effects. The science instruments on Juno have a tight power budget, but if they maintained contamination control, this is doable.
I’ll update this post with the launch video when it’s available. Good luck and safe journey, Juno!
UPDATED and bumped: Launch was at 12:25 ET.