Youtube Stream: Iridium-2 Launch Webcast
Mission Overview via the Press Kit:
SpaceXs Falcon 9 rocket will deliver 10 satellites to lowEarth orbit for Iridium, a global leader in mobile voice and data satellite communications. This is the second set of 10 satellites in a series of 75 total satellites that SpaceX will launch for Iridiums next generation global satellite constellation, Iridium® NEXT.
SpaceX is targeting launch of Iridium-2 from Space Launch Complex 4E (SLC-4E) at Vandenberg Air Force Base in California. The instantaneous launch window is at 1:25 p.m. PDT, or 20:25 UTC, on Sunday, June 25. The satellites will begin deployment about an hour after launch. A backup launch opportunity opens at 1:19 p.m. PDT, or 20:19 UTC, on Monday, June 26.
Following stage separation, the first stage of Falcon 9 will attempt a landing on the Just Read the Instructions droneship that will be stationed in the Pacific Ocean.
Flying with larger & significantly upgraded hypersonic grid fins. Single piece cast & cut titanium. Can take reentry heat with no shielding.
Elon Musk‏ (@elonmusk) June 24, 2017
Elon Musk‏ (@elonmusk) June 24, 2017
SpaceX said:Iridium-2 is the first mission Falcon 9 will fly with upgraded titanium grid finsdesigned to provide greater control authority and withstand high reentry heat, which is important for rocket reusability.
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Ars Technica: For Sundays launch, SpaceX to test significantly upgraded grid fins
This is a fairly conventional launch for SpaceX except for one novelty, revealed by SpaceX founder Elon Musk on Saturday night. After lifting 10 Iridium NEXT satellites to low Earth orbit, the Falcon 9's first stage will attempt to return to a droneship with a new, more durable set of grid fins, which help to stabilize the rocket as it descends back to Earth.
During prior missions these grid fins, manufactured from aluminum with added thermal protection, have caught fire due to atmospheric heating. To address this problem the company has forged new grid fins from titanium. "Flying with larger & significantly upgraded hypersonic grid fins," Musk tweeted. "Single piece cast & cut titanium. Can take reentry heat with no shielding." The new fins are a bit heavier, but are designed for multiple re-uses as SpaceX seeks to more toward rapid reuse of its first stage booster.
The Falcon 9 rocket's first stage being used for Sunday's mission is a good candidate for future reuse. Friday's launch of BulgariaSat-1 employed the Falcon 9 rocket first used in January to launch 10 satellites for Iridium's new constellation. This rocket will have a similar flight profile to January's launch, and therefore will be able to perform a "boostback" burn. This helps to reduce heating during atmospheric reentry.