Hopes to kick off a “working week” with as many as four U.S. launches in four days came to nothing as a gloomy Monday morning on the Space Coast scuppered SpaceX’s earnest efforts to get a previously-flown Falcon 9 booster off the ground from historic Pad 39A at the Kennedy Space Center (KSC). The Hawthorne, Calif.-headquartered launch provider planned to fly a pair of Falcon 9s—the veteran B1058, making its third flight in four months, and the sparkling-new B1062—within 36 hours of one another, setting a new SpaceX record for the shortest interval between missions on the East Coast. Sadly, it was not to be.
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However, as many as three flights may still take place this week, beginning just past midnight tonight, as United Launch Alliance (ULA) prepares to get its snakebitten Delta IV Heavy off the ground at 12:02 a.m. EDT Tuesday. Launching from Space Launch Complex (SLC)-37B at Cape Canaveral Air Force Station, Fla., the 235-foot-tall (72-meter) heavylifter—the second most powerful booster in active operational service, anywhere in the world—is tasked with delivering the highly secretive NROL-44 payload on behalf of the National Reconnaissance Office.
Already running more than a month overdue, the Delta IV Heavy has fallen foul to a ground pneumatics control system problem, a visually dramatic “Hot Fire Abort”, triggered in response to a torn diaphragm in a regulator, and a recent hydraulic issue with the launch pad’s swing-arm system, before ULA announced early Monday that the pieces were finally in place for liftoff at two minutes past midnight on Tuesday morning.
Current predictions from the 45th Weather Squadron at Patrick Air Force Base indicate that the intractable Florida will take a turn for the worst, then for the better, as the week progresses. “Winds will turn to the south today, ahead of an approaching cold front moving into the southeastern U.S.,” it noted in its Monday morning update. “As a result, afternoon and evening showers and thunderstorms will focus closer to the east coast of Florida, where boundary interactions are more likely.”
Rollback of the 300-foot-tall (100-meter) Mobile Service Tower (MST) on its rail-tracks is slated for Monday afternoon, exposing the Delta IV Heavy in all its majesty to the elements. Moving at a glacial pace of a quarter-mile-per-hour (0.4 km/h), the MST rollback should take almost an hour, before it halts and is declared “hard-down” in its launch position. According to ULA CEO Tory Bruno, the relatively late rollback (only a few hours before T-0) is being done as part of efforts to best protect the rocket and payload.
“During MST Roll, isolated storms will bring a threat for heavy rain, lightning and brief wind gusts in excess of 30 knots,” the 45th continued in its Monday morning summary of the gloomy outlook. “Whilst most of the storms are expected to diminish before midnight, remnant cloud cover will still bring a chance of a Thick Cloud Layer, Anvil Cloud or Cumulus Cloud violation during the launch window.”
All told, this is expected to produce a 60-percent chance of acceptable conditions in time for the Delta IV Heavy’s launch at 12:02 a.m. EDT Tuesday. However, should the launch slip to Wednesday, a noticeable downturn to only 40-percent-favorable is anticipated.
“Stronger southwest flow is expected Tuesday as the front moves in the eastern Gulf of Mexico, resulting in scattered to numerous offshore-moving showers and storms,” noted the 45th. “Given the front’s proximity to the area, the probability of weather-related violations is higher in the event of a 24-hour delay.” But the expected arrival of cooler air filtering in behind the front on Wednesday afternoon is expected to produce a 90-percent-favorable outlook should the launch slip to Thursday.
None of this, unfortunately, aided Monday morning’s planned launch of B1058 and its cargo: another 60-strong batch of Starlink internet communications satellites, bound for low-Earth orbit. This mission has been waiting in the wings for more than a week, having initially been targeted to fly on 17 September.
But that first launch attempt was routinely postponed by 24 hours in response to the indirect threat posed to the Space Coast by Tropical Storm Sally. Although SpaceX noted that it would be closely “watching the weather” on the 18th, it ultimately opted to stand down from further launch preparations, pointing to predicted poor sea conditions in the booster recovery area.
This likely would have hampered the efforts of the Autonomous Spaceport Drone Ship (ASDS), “Just Read the Instructions”, to safely execute its third East Coast “catch” of a returning Falcon 9 core. “Current was too strong for drone ship to hold station,” SpaceX founder Elon Musk tweeted. “Thrusters to be upgraded for future missions.” This is one of very few occasions where SpaceX has prioritized the safe return of a booster as a deciding factor in scrubbing a launch. Of course, Starlink is an in-house SpaceX program and on a commercial or government launch the safe return of the booster ordinarily would not be prioritized over the safe delivery of the payload.
Following the scrub, JRTI returned to Port Canaveral on 20 September and a few days later her sister ASDS, “Of Course I Still Love You”—veteran of over 30 successful Falcon 9 recoveries since April 2016—put to sea in her stead, bound for a position about 390 miles (630 km) off Cape Canaveral in the Atlantic Ocean.
Launch preparations for this morning’s 10:22 a.m. EDT liftoff entered high gear about 35 minutes before T-0, when SpaceX engineers began loading liquid oxygen and a highly refined form of rocket-grade kerosene (known as “RP-1”) into the Falcon 9 propellant tanks. However, the weather deteriorated to 40-percent-favorable and remained “Red” (“No-Go”) throughout those final minutes, making a scrub a virtual inevitability.
Nevertheless, SpaceX pressed right up to the wire, continuing the countdown under murky Florida skies, as cameras on the heaving deck of the ASDS presented a similarly unfavorable picture. At one point, the Falcon 9’s payload fairing was barely visible in the gloom. Finally, at T-31 seconds, when it became clear that Mother Nature would not give ground, a halt was called and the launch attempt was formally scrubbed. No backup date has yet been set.
As such, the manifests of ULA, SpaceX and also Northrop Grumman Corp. have aligned to present as many as three launches over the coming days. Assuming NROL-44 flies on time just after midnight tonight, another Falcon 9—powering away from the Cape’s SLC-40 under the thrust of its brand-new B1062 core—will launch during a 15-minute “window” which opens at 9:55 p.m. EDT Tuesday. That mission will deliver the fourth Global Positioning System (GPS) Block III navigation and timing satellite into Medium Earth Orbit (MEO) on behalf of the U.S. Space Force.
And two days later, at 9:38 p.m. EDT Thursday, Pad 0A at the Mid-Atlantic Regional Spaceport (MARS) on Wallops Island, Va., will reverberate to the roar of an Antares 230+ booster, as it delivers the NG-14 Cygnus cargo ship—named in honor of STS-107 astronaut Kalpana “K.C.” Chawla—to the International Space Station (ISS). Laden with 7,758 pounds (3,519 kg) of payloads, equipment and supplies for the incumbent Expedition 63 and forthcoming Expedition 64 crews, NG-14 was originally targeted to fly late Tuesday, but was itself postponed in response to anticipated bad weather at Wallops.
In Florida, too, that weather remains the deciding factor. The outlook for Tuesday night’s Falcon 9 mission with GPS III-04 currently sits at only 40-percent-favorable, improving to 90-percent-favorable in the event of a slip to Wednesday night. Lingering clouds and unsettled weather from afternoon convection on Tuesday are expected to clear out by Wednesday. Combined with a northwesterly movement of winds, cooler air should arrive in the region, according to the 45th Weather Squadron.