SpaceX is targeting Sunday evening for the first polar launch from Florida since 1969. On board the Falcon 9 rocket is the Argentinean SAOCOM-1B satellite and two American secondary payloads. Liftoff from Space Launch Complex 40 (SLC-40) is targeted for 7:18 PM EDT (23:18 UTC) on Sunday, August 30, during a launch window that lasts ten minutes.
The 45th Weather Squadron predicts a 40% chance of acceptable weather for Sunday’s launch window. Should weather, a technical issue, or anything else prevent a liftoff on Sunday, a backup launch opportunity exists on Monday, also with a 40% chance of acceptable weather for that attempt.
Unlike most launches from Cape Canaveral, which take advantage of the Earth’s spin in order to reach low inclination orbits, the SAOCOM-1B mission will fly southward, along the east coast of Florida, along a flight path known as the polar corridor. This is the first mission to launch to polar orbit from Florida since February 26, 1969, when a Delta E1 rocket launched the ESSA-9 meteorology satellite.
SAOCOM-1B will be deployed into a Sun Synchronous Polar orbit, inclined 97.9 degrees at an altitude of 620 kilometers. The satellite will compliment the SAOCOM-1A satellite, which was also launched aboard a SpaceX Falcon 9 from Vandenberg Air Force Base, California, on October 7, 2018.
Vandenberg has been the regular launch site for missions to polar orbits, which orbit Earth over the poles, aligned north to south. Vandenberg is preferable for these launches as the Pacific Ocean offers an unpopulated area directly south of the launch site, minimizing risk to public safety in the unlikely event of a launch failure. SpaceX continues to operate Space Launch Complex 4 East (SLC-4E) at Vandenberg, and still plans to launch missions from California, including the Sentinel-6A mission for NASA no earlier than November 2020.
However, in order to enable more frequent launches to polar orbits, SpaceX has worked with the US Space Force’s 45th Space Wing, which controls the eastern range including Cape Canaveral, to resume polar launches from Florida as well. Cape Canaveral is located closer to the equator than Vandenberg, which is beneficial for rocket performance to low inclination orbits but worsens performance to high inclination orbits such as Sun Synchronous Orbit.
Unlike launches from Vandenberg, launching directly to a polar inclination from Florida would result in overflying populated areas of Florida. Therefore, Falcon 9 will initially fly southeast along the coast of Florida. After stage separation, the second stage will perform a “dogleg” turn to the south to achieve the proper inclination.
While this will avoid overflying Florida, it will result in the second stage and its payloads flying over Cuba. However, at this point in flight, the vehicle will be much higher, and the risk from falling debris from a potential anomaly is much lower than during the earlier phases of flight.
The risk of an early flight failure was a major consideration in scheduling the SAOCOM-1B launch. Due to the unique flight path, Falcon 9 will nearly overfly the Cape Canaveral launch pads to the south of SLC-40, which includes SLC-37B, where a United Launch Alliance Delta IV Heavy rocket and its valuable, classified NROL-44 payload currently stand.
While both ULA and SpaceX have agreed to allow launches to the polar corridor to overfly each other’s pads (Polar ULA Atlas V launches from SLC-41 would overfly SpaceX at SLC-40), the National Reconnaissance Office had specially requested that SAOCOM-1B not be launched while the NROL-44 payload is at SLC-37B.
So when the Saturday morning launch attempt for NROL-44 was aborted just seconds before liftoff, it was believed that SAOCOM-1B would be delayed in order to wait its turn. However, the NRO reevaluated the risk from a nearby overflight, and granted SpaceX permission to launch SAOCOM-1B while NROL-44 is still on the ground. This may have been influenced by the minimum seven-day delay to NROL-44’s liftoff.
Así cargábamos el #SAOCOM1B en el avión Antonov AN124
El procedimiento se realizó en dos fases. Se abren los dos extremos del avión, por el frente se carga el satelite y, por la parte posterior, los paneles solares y el equipo soporte.
#ArgentinaUnida #HaciaElFuturo pic.twitter.com/Oph4jWcsRY
— CONAE (@CONAE_Oficial) February 21, 2020
The SAOCOM-1B spacecraft was initially shipped to the launch site on February 22, 2020. Initially scheduled or a launch in spring, the mission was indefinitely delayed due to the COVID-19 pandemic, which prevented CONAE team members from travelling to Florida to support the launch.
The 1600-kilogram satellite is operated by CONAE, Argentina’s government space agency. The pair of SAOCOM-1 satellites carry L-band Synthetic Aperture Radar (SAR) instruments to measure soil moisture and other parameters in support of emergency response and disaster relief. The SAOCOM constellation will work in cooperation with the four Italian COSMO-SkyMed satellites.
Also on board the launch are two secondary payloads. One is the GNSS Navigation and Occultation Measurement Satellites (GNOMES-1) satellite, a 30-kilogram microsatellite built by Blue Canyon Technologies for American Earth science company EarthIQ. GNOMES-1 receives signals from four Global Navigation Satellite Systems (GNSS): the American GPS constellation, Russian GLONASS, European Galileo, and Chinese BeiDou satellites. By measuring these signals as they pass through Earth’s atmosphere, PlanetIQ aims to improve weather forecasting models.
The second rideshare payload on board is Tyvak-0172, a satellite from Tyvak Nano-Satellite Systems. Details on the size and mission of this satellite are unknown.
The SAOCOM-1B launch is also the one hundredth ever launch for the Falcon family, including the Falcon 1 and Falcon Heavy rockets. Also notable is the stage one landing, which will occur at Landing Zone 1 (LZ-1) at Cape Canaveral, not a drone ship in the ocean. This will be the first Return to Launch Site (RTLS) landing since the CRS-20 mission on March 7, 2020.
The booster that performed that landing is the same first stage launching SAOCOM-1B. B1059.4 previously launched the CRS-19, CRS-20, and Starlink v1.0 L10 missions.
In addition to stage one recovery, the SpaceX fairing recovery vessel GO Ms. Chief is stationed downrange, west of The Bahamas, to attempt to catch one half of the payload fairing. The other half will be recovered after a soft splashdown. Both halves cannot be caught due to the other recovery vessel, GO Ms. Tree, being stationed northeast of Cape Canaveral for the Starlink v1.0 L11 mission. That recovery attempt will occur approximately 45 minutes after launch, weather conditions permitting.
After the second stage reaches orbit and shuts down its Merlin Vacuum engine, there will be a four minute long coast phase prior to deployment of the primary payload, SAOCOM-1B. There will then be a 47 minute long coast phase prior to deployment of GNOMES-1 and Tyvak-0172.
(Lead photo via SpaceX)
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