Update for Dec. 19: SpaceX has successfully launched the NROL-108 spy satellite for the National Reconnaissance Office. Read our full story here.
CAPE CANAVERAL, Fla. — SpaceX (opens in new tab) is set to launch a spy satellite into orbit for the U.S. National Reconnaissance Office (NRO) on Thursday (Dec. 17), and you can watch the action online.
The flight is scheduled to blast off from Pad 39A at NASA's Kennedy Space Center here in Florida during a planned three-hour window that opens at 9 a.m. EST (1400 GMT). However, the exact liftoff time has not yet been announced.
You can watch the launch live here (opens in new tab) and on the Space.com homepage, courtesy of SpaceX, beginning about 15 minutes before liftoff. You'll also be able to watch the launch directly from SpaceX here (opens in new tab).
Related: SpaceX's 1st secret US military satellite launch (& landing) in photos
This mission will mark the 31st launch this year for SpaceX and its workhorse Falcon 9 rocket (opens in new tab), as well as the third Falcon 9 to fly in a little over a week. On Dec. 6, SpaceX kicked off its final launch run of the year by ferrying an upgraded cargo Dragon spacecraft (opens in new tab) to the International Space Station, marking the first time there were two such craft attached to the orbital outpost. A few days later, the California-based rocket builder launched a radio satellite into orbit for Sirius XM.
Now, SpaceX will close out a record-setting year with a bang. The company announced that this mission, dubbed NROL-108, includes a rare treat: an upright Falcon 9 booster landing at Landing Zone 1 (LZ-1) at Cape Canaveral Space Force Station (opens in new tab), as opposed to the more common drone-ship landings at sea.
To date, SpaceX has successfully recovered 69 first-stage boosters, 20 of which touched down on terra firma. For its 70th, the company's Falcon 9 will touch down at one of the company's landing sites just 9 miles (14 kilometers) from where it lifted off. SpaceX warned central Florida residents that they should expect to hear sonic booms as the rocket touches down at LZ-1.
"There is the possibility that local residents may hear one or more sonic booms during the landing attempt," SpaceX officials said in an advisory emailed out to the media. "Residents of Brevard County are most likely to hear one or more sonic boom, although what residents experience will depend on weather conditions and other factors."
Officials at the U.S. Air Force's 45th weather squadron have said that the weather looks good for Thursday's attempt, with 70% chance of favorable conditions (opens in new tab) for launch. The main issues for concern are liftoff winds and potential for a thick cloud layer.
Related: Hitch a ride to space (and back) on a Falcon 9 in this awesome video
The star of today's mission will be one of SpaceX's frequent flyers — a Falcon 9 first stage known as B1059. This will mark the booster's fifth launch and landing attempt. Previously it ferried two different Dragon cargo resupply missions to the International Space Station (CRS-19 (opens in new tab) in December 2019 and CRS-20 (opens in new tab) in March of this year), launched the Starlink 8 (opens in new tab) mission in June, and most recently lofted the SAOCOM-1B Earth-observing satellite (opens in new tab) into orbit for Argentina on Aug. 30.
Thursday's flight will mark the 102nd overall launch of a Falcon 9 rocket and the 70th first stage recovery. SpaceX's drone ship "Of Course I Still Love You" is sidelined for this mission as the booster will attempt its second touchdown on land in a row. (Previously in August it landed at LZ-1 after carrying SAOCOM-1B to space.) That touchdown will occur approximately nine minutes after liftoff.
The company's other drone ship, "Just Read the Instructions" is on its way to Port Canaveral, toting a seven-time flyer. That booster, B1049, became the second in SpaceX's fleet of veteran rockets to launch and land seven times (opens in new tab) when it ferried the first of two massive radio broadcasting satellites into space for Sirius XM on Sunday (Dec. 13). The second Sirius XM satellite is set to launch sometime next year, and the duo are expected to replace aging satellites already on orbit.
GO Ms. Tree, one of SpaceX's net-equipped boats, is heading to the recovery zone to await today's launch. It's unclear yet if the vessel will attempt to catch the Falcon 9's falling payload fairing (opens in new tab) — the protective "nose cone" that surrounds a satellite during launch — or if SpaceX will just scoop the two halves out of the ocean. (Whether or not a catch is attempted depends on a number of factors, including weather and sea conditions at the recovery zone.)
SpaceX has been successful in its attempts to reuse more of the Falcon 9, even reusing several fairings on multiple missions. The payload fairing accounts for approximately 10% of the cost of the rocket, which is roughly $62 million (opens in new tab). Reusing fairings could save as much as $6 million per flight, SpaceX founder and CEO Elon Musk has said.
The company has been reusing payload fairings, and even used its first refurbished fairing on a paying customer's flight. The Sirius XM-7 mission featured one fairing half that previously flew on the Anasis-II mission (opens in new tab) earlier this summer, which launched a communications satellite for South Korea's military.
Today's mission will mark the final launch from Florida for 2020. In total 31 missions have launched from the area this year, and 26 of those have been on SpaceX rockets.
Follow Amy Thompson on Twitter @astrogingersnap. Follow us on Twitter @Spacedotcom or Facebook.