Rounding off a record-breaking and historic launch manifest for 2020, SpaceX conducted its second dedicated launch for the United States National Reconnaissance Office (NRO) on Saturday – following a scrub on Thursday – with a flight-proven Falcon 9 carrying out the NROL-108 mission.
Liftoff from the Kennedy Space Center’s Launch Complex 39A (LC-39A) occurred at the start of a three-hour window, at 09:00 EST (14:00 UTC) on Saturday.
This mission marked the 103rd launch of SpaceX’s Falcon 9 rocket since its first flight in June 2010 and its 26th launch in 2020. This is a new record for SpaceX, having broken their previous record of 21 launches set two years prior.
The launch comes only a handful of days after SpaceX tied their reusability record by successfully launching and recovering a Falcon 9 booster for a seventh time during the SXM-7 mission, which was launched from the Cape Canaveral Space Force Station’s Space Launch Complex 40 (SLC-40) on Sunday, 13 December.
SpaceX has once again elected to use a flight-proven Falcon 9 core to launch Thursday’s mission, with approval from the National Reconnaissance Office. The booster used was B1059, which launched its fifth mission total. It previously supported the launches of the CRS-19, CRS-20, Starlink V1 L8, and SAOCOM 1B missions, respectively.
This mission marked B1059’s fourth flight this year alone.
The name NROL-108, shortened from NRO Launch 108, is part of an arbitrary numbering system used to identify the NRO’s satellites – without disclosing their identities – before launch.
Once in orbit, payloads are usually assigned another numerical designation, prefixed by the letters USA. In recent years, these USA designations have been assigned sequentially, with USA-312 the next available designation in the sequence.
NROL-108’s existence was kept in shadow until late September when it was revealed in a Federal Communications Commission (FCC) filing – a document that launch providers submit in order to gain approval to carry out necessary communications between the launch vehicle and its ground stations – and confirmed to be launched under NRO jurisdiction.
The mission was previously set to launch sometime in October but was subsequently pushed back to December for reasons that are unknown.
Like most NRO missions, the identity of the satellite – or satellites – will not be divulged during the mission, just as the satellite’s target orbit and nature of the mission will be kept secret during launch. However, ground observers will be able to find the satellite after launch and calculate its orbit.
Nevertheless, certain things are known.
SpaceX and the NRO have confirmed that Falcon 9’s first stage was to fly back towards Cape Canaveral Space Force Station to land at SpaceX’s Landing Zone 1. Ahead of the launch, notices to airmen (NOTAMs) and mariners were released, establishing hazard areas that show the course NROL-108 will take after leaving the Kennedy Space Center.
Launch hazard areas for the NROL-108 mission
The rocket headed in a north-easterly direction, flying out over the Atlantic Ocean.
This indicates the payload will be placed into an inclined orbit and is definitely not bound for geosynchronous orbit (due to the Return To Launch Site (RTLS) landing flight profile for the first stage). The hazard area off the coast of Florida suggests an orbit inclined at around 50 degrees.
A second hazard area in the eastern Pacific Ocean is likely to be for the deorbit of the second stage. This suggests either a deorbit burn during the first to third revolutions of a low Earth orbit mission or the first revolution of an intermediate orbit for a spacecraft that would later maneuver into an elliptical Molniya orbit.
NROL-108 was the second NRO mission launched by SpaceX, with the first – NROL-76 – having launched on a Falcon 9 from LC-39A on 1 May 2017. The two missions share similarities in terms of flight profiles and possible destinations; however, this mission is different in the sense that it will utilize flight-proven hardware.
The NRO’s mission patch and fairing art for NROL-108 displays a gorilla, with the motto “Peace Through Strength” printed on the outer circle. According to the agency, this mission represents a gorilla in the sense that “it is constantly vigilant and ready to defend its own, demonstrating NRO’s commitment to protecting U.S. warfighters, interests, and allies.”
The Falcon 9 launch vehicle and payload were rolled out to the pad and raised to vertical on Wednesday. Typically, SpaceX prefers to conduct a static fire test of the Falcon 9’s Merlin-1D first stage engines a handful of days before the launch; however, the company elected to forego such a test before this mission.
Although Falcon 9 was horizontal during remote setup, it is now vertical ahead of tomorrow's #NROL108 mission. We got a nice treat getting to watch from one of the setup spots.
I've uploaded a bunch of photos to the NSF L2 forum for members to peruse.https://t.co/VuJubQq3Iz pic.twitter.com/SBta5gyRSU
— Stephen Marr (@spacecoast_stve) December 16, 2020
NROL-108 now joins only four other missions (Starlink v1.0 L8, L11, L12, and SAOCOM 1B) in skipping the pre-launch static fire.
Following the two day recycle following a sensor issue-related scrub, the launch day countdown entered its business end at the T-38 minute mark when the launch director polled the mission teams to proceed into propellant loading operations. With the “go” is given, chilled RP-1 fuel began flowing into both stages of the Falcon 9 launch vehicle at 35 minutes to liftoff, along with liquid oxygen (LOX) loading into the first stage. LOX loading onto Falcon 9’s second stage started at T-16 minutes.
At T-7 minutes prior to liftoff, the liquid oxygen pre-valves on the nine Merlin-1D first stage engines opened, allowing LOX to flow through the engine plumbing and condition the turbopumps for ignition. This process is known as “engine chilling” and is used to prevent thermal shock that could damage the engines upon startup.
The Falcon 9’s onboard flight computers took control of the countdown and ran through final checks of the vehicle’s systems and finalize tank pressurization starting at the T-1 minute mark. The launch director gave a final “go” for launch approximately 15 seconds later.
The nine Merlin-1D engines on the first stage ignited at T-3 seconds, with liftoff taking place at T0 following a quick final check by the onboard computers to verify that all systems are operating nominally.
One minute 12 seconds after liftoff, Falcon 9 passed through Max-Q, the area of maximum dynamic pressure or the point in the flight at which the combination of air density and the speed of the vehicle result in it experiencing the greatest aerodynamic loads.
Illustration of a standard Falcon 9 launch and return-to-launch-site landing profile – credit: SpaceX
The first stage engines burned for the first 2 minutes and 18 seconds of flight. The burn ended when all nine engines shut down in an event known as Main Engine Cutoff (MECO).
Payload fairing separation occurred approximately 11 seconds after second stage ignition and was the final orbital flight milestone to be announced publicly per standard NRO rules that launch coverage end at payload fairing separation.
Following this, the second stage and payload continued on to orbit in secrecy, with successful spacecraft separation expected to be confirmed sometime after the launch.
Meanwhile, Falcon 9’s core B1059 first stage returned to the Cape Canaveral Space Force Station as part of its planned landing. This commenced with the start of the boostback burn, at 13 seconds after stage separation.
Touchdown of the booster at SpaceX’s Landing Zone 1 occurred approximately 8 minutes and 15 seconds after launch. The vehicle will then be secured and transported back to SpaceX’s facilities at the Cape following safing operations upon landing.
A Falcon 9 booster performs a successful landing at SpaceX’s Landing Zone 1 during the SAOCOM 1B mission – credit: SpaceX.
Likewise, the two payload fairing halves will parachute to the Atlantic Ocean for recovery. Two ships, GO Ms. Tree and GO Searcher, will be stationed about 330 kilometers off the coast to assist in their recovery. GO Ms. Tree’s sister ship, GO Ms. Chief, is currently undergoing maintenance in Port Canaveral.
This mission marked the end to a busy year for the Hawthorne, California-based aerospace company, with a record number of launches under their belt, two crewed flights to the International Space Station for NASA, and a hectic series of testing campaigns involving assorted prototypes of their next-generation Starship spacecraft at their Boca Chica, Texas launch and production facility.
SpaceX is expected to start its 2021 campaign with the launch of the Transporter-1 mission – the first dedicated flight under the company’s Smallest Rideshare Program. The mission is currently scheduled to launch on a southerly trajectory from Cape Canaveral no earlier than 14 January 2021.
(Lead photo via Stephen Marr for NSF)