Six-Times-Flown Falcon 9 Lofts SWOT Ocean Watcher from Vandenberg

The Surface Water and Ocean Topography (SWOT) spacecraft vanishes into the darkness, less than an hour after Friday’s launch. Photo Credit: NASA

The pre-dawn darkness and calm of Vandenberg Space Force Base, Calif., was broken at 3:46 a.m. PST (6:46 a.m. EST) Friday by the roar and dazzle of a six-times-flown Falcon 9 booster, laden with the NASA-led Surface Water and Ocean Topography (SWOT) satellite, designed for a three-year-plus investigation of the changeability of surface water bodies over time. And for the third time in a little more than one week—once on the West Coast and twice on the East—rocket-watchers were left rapt as another booster pirouetted its way back to an on-point touchdown on solid ground.

Video Credit: NASA

This morning’s launch was conducted by B1071, which entered the Falcon 9 fleet in February and had already flown five times by October. Her first pair of missions in February and April delivered the highly classified NROL-87 and NROL-85 payloads to orbit on behalf of the National Reconnaissance Office, whilst a third in mid-June lofted Germany’s SARah-1 radar-imaging surveillance satellite.

More recently, in late July and early October, she boosted two Starlink batches—a total of 98 SpaceX-built internet communications satellites—into low-Earth orbit. With this morning’s flight, B1071 has launched a full half of the 12 total Falcon 9 missions flown out of Vandenberg so far in 2022.

B1071 first flew on 2 February 2022, delivering the classified NROL-87 payload to orbit for the National Reconnaissance Office. Photo Credit: SpaceX

In fact, this year has already doubled SpaceX’s previous record of six Falcon 9 launches from Vandenberg in a single calendar year, executed back in 2018. In addition to the two highly classified NRO payloads, SARah-1 and this morning’s SWOT, a total of 392 Starlinks have been launched on eight missions. Also sitting on the manifest, possibly targeting a late December launch, is Israel’s EROS-C3 multispectral imaging spy satellite.

Friday morning’s launch was devoted to SWOT, a 4,400-pound (2,000-kilogram) satellite built by Thales Alenia Space for emplacement into orbit at an altitude of 533 miles (857 kilometers), inclined 77.6 degrees to the equator. Jointly developed by NASA and the Centre national d’études spatiales (CNES, the French national space agency), with collaboration from the Canadian Space Agency (CSA) and the UK Space Agency (UKSA), the satellite will spend up to three years globally surveying Earth’s surface water to understand ocean-surface topography and the mechanisms responsible for changing terrestrial water bodies over time.

Video Credit: Jet Propulsion Laboratory (JPL)

In doing so, this mission will offer the first truly “global” measurements of water levels, observing ocean circulation across 90 percent of the globe at scales as fine as 9.3-15.5 miles (15-25 kilometers), an order of magnitude better than has ever been achieved to date. SWOT will employ the Ka-Band Radar Interferometer (KaRIn), a powerful Synthetic Aperture Radar (SAR) interferometry tool.

Its twin radar antennas—positioned at opposite ends of a 33-foot-long (10-meter) mast—will permit measurements of surface water elevation over a 75-mile (120-kilometer) swath. In a sense, this mission will be not unlike (though much smaller than) the interferometry radar mast deployed by Endeavour’s STS-99 crew during the Shuttle Radar Topography Mission (SRTM) back in February 2000.

The Surface Water and Ocean Topography (SWOT) spacecraft will spend up to three years examining more than 90 percent of Earth’s surface. Photo Credit: Thales Alenia Space

SWOT arrived at Vandenberg in the third week of October, aboard an Air Force C-5 Galaxy airlifter, and was transferred to the Astrotech Space Operations facility for pre-flight fueling and other processing steps. Originally set to fly on 5 December, launch was rescheduled firstly for No Earlier Than (NET) the 12th, and eventually the 15th, to permit teams to complete requisite processing activities and allow SpaceX to finish up checkouts of the Falcon 9 booster.

Last Friday, SWOT was encapsulated inside the two-piece (or “bisector”) payload fairing and on Saturday, 10 December, B1071 was put through a Static Fire Test of its nine Merlin 1D+ core stage engines at SLC-4E. A subsequent Flight Readiness Review (FRR) confirmed that all personnel and activities were in lockstep for the opening launch attempt on Thursday, 15 December.

Video Credit: Jet Propulsion Laboratory (JPL)

However, another 24-hour postponement was announced late Wednesday evening. “After SpaceX’s Falcon 9 went vertical on the pad…teams identified moisture in two Merlin engines on the rocket’s first-stage booster,” NASA reported. “Teams completed inspections of the rocket’s engines today, but will use the additional time to complete data reviews and analysis before a launch attempt.”

It marked another unwelcome delay for one of SpaceX’s longest-running launch services contracts. The Hawthorne, Calif.-headquartered organization won the $112 million contract back in November 2016, at which stage SWOT was set to launch in April 2021.

Friday’s mission saw the third “land” landing of a Falcon 9 booster in just over a week. Image Credit: SpaceX

The satellite’s own wait for launch has been even longer. Originally identified as an accelerated Decadal Survey Tier 2 mission—and a key Earth Science priority, recommended by the National Research Council (NRC)in NASA’s Responding to the Challenge of Climate and Environmental Change report, published in June 2010, it was aimed for launch in the 2019-2020 timeframe. It commenced its formal mission development journey in the fall of 2012 and in May 2014 NASA Administrator Charlie Bolden and CNES President Jean-Yves Le Gall signed agreements to officially transition SWOT from a feasibility study into full mission implementation.

In January 2015, Thales Alenia Space was contracted to build SWOT and the mission passed its Critical Design Review (CDR) precisely on schedule in late 2017. More recently, in the summer of 2021 the satellite was shipped to the company’s facilities in Cannes, France, for the integration of its scientific payload and by the close of last year SWOT’s launch was formally scheduled for November 2022.

B1071 powers into the night at 3:46 a.m. PST (6:46 a.m. EST) Friday. Photo Credit: SpaceX

Liftoff of B1071 occurred at 3:46 a.m. PST (6:46 a.m. EST), right at the start of Friday’s ten-minute “launch window”. The nine Merlins burned furiously for the first 2.5 minutes of flight, with a combined thrust of 1.5 million pounds (680,000 kilograms), before B1071 separated and headed an on-point touchdown on Landing Zone (LZ)-4 at Vandenberg.

It marked the seventh Vandenberg touchdown by a Falcon 9 core since October 2018 and the fourth at LZ-4 this year alone. And when one adds six other missions which returned to alight on either LZ-1 or LZ-2 at Cape Canaveral—a total of seven boosters, including the side-boosters of last month’s Falcon Heavy following the highly secretive USSF-44 mission for the U.S. Space Force—2022 has set a new record for the greatest number of “land” landings by SpaceX birds.

Impressive view from the rocket as B1071 climbs skyward for the sixth time. Photo Credit: SpaceX

Attention now returns to the Space Coast, where SpaceX aims to launch a pair of Falcon 9s within a day of one another, later on Friday afternoon and also on Saturday afternoon. First up at 4:21 p.m. EST Friday from storied Space Launch Complex (SLC)-40 will be the eight-times-used B1067 booster, carrying the first pair of O3b mPOWER broadband satellites, flying on behalf of Luxembourg-based SES. Both satellites are destined for injection into Medium Earth Orbit (MEO).

Original plans envisaged launching a second mission—flown by B1058, the same booster that lofted Doug Hurley and Bob Behnken aboard Dragon Endeavour for the historic Demo-2 in May 2020—just 18 minutes later from neighboring Pad 39A at the Kennedy Space Center (KSC). Making a record-breaking 15th launch, B1058 is tasked with delivering this year’s 33rd batch of Starlink internet communications satellites into orbit.

The Merlin 1D+ Vacuum engine of the Falcon 9’s second stages burns brightly (left pane) as B1071 returns to an on-point “land” landing (right pane). Photo Credit: SpaceX

If achieved, flying two missions within 18 minutes of each other might have seen SpaceX break its own record—for the third time this year—for the shortest interval between two Falcon 9 launches. Last December, it set a new personal best of just 15 hours and seven minutes between a pair of missions from the West and East Coasts.

Then, last June, the back-to-back flights of Germany’s SARah-1 from Vandenberg and Globalstar-2 from the Cape narrowed that record still further to 14 hours and eight minutes, before the launches of Dragon Endurance and Crew-5’s Nicole Mann, Josh Cassada, Koichi Wakata and Anna Kikina from KSC and a Starlink flight from the West Coast were achieved seven hours and ten minutes apart in early October.

With Friday morning’s launch, B1071 has now logged six missions in 2022 alone. Photo Credit: SpaceX

Hopes of shortening that personal best yet further to six hours last month came to nought, when B1049 successfully rose from SLC-40 with the Eutelsat 10B communications satellite, but the CRS-26 Cargo Dragon—bound for the International Space Station (ISS)found itself delayed four days due to unfavorable weather on the Space Coast. That was a pity, for flying Eutelsat 10B and CRS-26 within hours of each other might have set a new record, not only for time between any pair of Falcon 9 launches, but also a new record for time between Falcon 9 launches from the same launch site.

However, Friday’s hoped-for double-header was not to be. Late Thursday, SpaceX announced that it was “prioritizing” the O3b mPOWER mission—and its external customer, SES—and correspondingly moved B1058’s Starlink mission back 24 hours, with a revised No Earlier Than (NET) of 4:32 p.m. EST Saturday.

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