There are two launches happening this Sunday, and both are set to broadcast live on NASA's official stream above. The first is a NASA International Space Station resupply mission, with a Norhtrop Grumman Cygnus spacecraft launching aboard an Antares rocket from Wallops Island in Virginia at 5:39 PM EST (2:39 PM PST). The second is the launch of the Solar Orbiter spacecraft, a joint scientific mission by NASA and the European Space Agency (ESA) that's set to take off aboard a United Launch Alliance (ULA) Atlas V rocket from Cape Canaveral, Florida at 11:03 PM EST (8:03 PM PST).
The ISS resupply mission is the 13th operated by Northrop Grumman, and it will carry around 8,000 lbs of experiment materials, supplies for the Station's astronaut crew, and additional cargo. If all goes to plan, the Cygnus spacecraft will get to the Space Station on Tuesday at around 4:30 AM EST, where astronauts on board will capture the spacecraft with the station's robotic arm for docking.
The NASA/ESA Solar Orbiter mission is a bit more of an event, since it's a launch of a very special payload with a dedicated mission to study the Sun, launching aboard a brand new custom configuration of ULA's Atlas V rocket tailor-made for the Orbiter. The Orbiter has a mass of nearly 4,000 lbs, a wingspan of nearly 60 feet and is carrying a complement of 10 instruments for gathering data from our Solar System's central player.
Solar Orbiter will take the first ever direct images of the Sun's poles once it arrives at our star, but it first has to get there, using the gravitational force of both Earth and Venus to help propel it along its path. Already, the planned launch of Solar Orbiter has been delayed by a few days – and timing is key to making sure those gravitational forces can work as designed to achieve its goal, so here's hoping today's launch goes off as planned.
As its name implies, Solar Orbiter is designed to orbit the Sun, and it'll do so from a relatively close distance of around 26 million miles away. That's closer than Mercury, the planet in our solar system closest to the Sun, and at that distance it'll face max temperatures of around 520 degrees Celsius (968 degrees Fahrenheit). To endure those temps, the spacecraft is protected by a titanium heat shield that will always be oriented towards the star, and even its solar panels will actually have to tilt away from the Sun during the spacecraft's closest approach to make sure they don't get too hot while powering the satellite.
Solar Orbiter will study the Sun's polar regions, as mentioned, and shed some light on how its magnetic field and emissions of particles from the star affect its surrounding cosmic environment, including the region of space that we inhabit here on Earth. After launch, Orbiter should make its way to Venus for a flyby this December, then cost paths with Earth for a planned approach in November, 2021, before making its first close approach to the Sun in 2022.
Check back above for live views of both launches, with the stream for the first mission kicking off shortly after 5 PM EST (2PM PST).