A roll of thunder broke the stillness of a foggy West Coast Monday afternoon, as United Launch Alliance (ULA)’s mighty Atlas V roared aloft from Area Launch Advanced (SLC)-3E at Vandenberg Area Drive Base, Calif., laden with the Landsat-9 payload on behalf of NASA and the U.S. Geological Survey (USGS).
Liftoff occurred on time at 11:12 a.m. PDT and Landsat-9—the latest in a series of Earth-monitoring and geological surveying spacecraft, whose heritage dates back almost five decades—is headed for insertion into near-polar, Solar-synchronous orbit. For the primary time, the Centaur was set to execute 4 “burns” of its highly effective RL10C-1 engine to raise Landsat and 4 CubeSat rideshare payloads to their desired orbital slots, earlier than deorbiting itself safely on the finish of its mission.
As outlined in AmericaSpace’s preview story, as we speak’s flight marks the primary ULA launch in additional than 4 months, following a irritating summer time which has seen the Area Take a look at Program (STP)-3 mission and the second Orbital Flight Take a look at (OFT-2) of Boeing’s troubled CST-100 Starliner to the Worldwide Area Station (ISS) extensively delayed.
STP-3 was initially set to fly in February, however was postponed till June in response to payload-readiness issues, earlier than being grounded once more in the wake of anomalous Centaur engine behavior during an Atlas V launch in May. In the meantime, the long-awaited OFT-2 mission discovered itself delayed from March till July, before it was stood down indefinitely in early August following a propulsion valve issue.
In marked distinction to those woes, the Landsat-9 marketing campaign has proceeded with relative smoothness, each the payload and its launch automobile—the Atlas V Frequent Core Booster (CCB) and Centaur higher stage—having arrived at Vandenberg in July.
Final month, Landsat-9 was encapsulated inside its Additional-Prolonged Payload Fairing (XEPF) and on 3 September the rocket was put by means of a fully-fueled Moist Gown Rehearsal (WDR) to iron out any points forward of launch. Two weeks in the past, the payload was connected atop the automobile, elevating the full top of the “stack” to 194 ft (59.1 meters).
A Launch Readiness Evaluate (LRR) on Saturday established a T-0 at 11:12 a.m. PDT, with the “window” for Monday’s opening try extending 26 minutes to 11:38 a.m. PDT.
At present’s countdown started about 3 a.m. PDT, eight hours earlier than the scheduled launch time, with clocks starting to rely from the T-7 hour level. This obvious discrepancy was as a result of presence of two built-in “holds”, every lasting half-hour: one at T-2 hours, simply previous to the onset of cryogenic fueling, and the second at T-4 minutes, earlier than the Terminal Rely.
The operation was carried out from the Distant Launch Management Heart (RLCC), located about 6.5 miles (10.4 km) from the pad. The rocket was promptly powered up, as groups labored to check the avionics and steering methods, forward of the rollback of the 260-foot-tall (79-meter) Cellular Service Tower (MST).
Climate circumstances held regular at 90-percent favorable, with Launch Climate Officer Capt. Addison Nichols of the U.S. Area Drive’s Area Launch Delta 30 climate squadron pointing to low stratus clouds at 700 ft (210 meters), unrestricted visibility, northwesterly winds of 10 gusting to fifteen knots and temperatures hovering close to 16 levels Celsius (62 levels Fahrenheit).
This favorable outlook allowed for a “Go to Roll” authorization from ULA Launch Conductor Scott Barney and ULA Launch Director Tom Heter III. Shortly after 5:30 a.m. PDT, high-pressure hydraulic cylinders started jacking the 11-million-pound (5-million-kg) MST to organize for rollback.
Over a interval of a couple of half-hour, the massive tower rolled away from the Atlas V to its “park” place, about 250 ft (76 meters) to the southeast. Now alone within the glare of floodlights, the Atlas V was put by means of additional exams of its flight controls to display that its RD-180 essential engine and the RL10C-1 engine of the Centaur may correctly cycle gas valves and execute steering instructions as issued. Pad crews departed SLC-3E shortly after 8 a.m. PDT and retreated away from the blast hazard zone, forward of the onset of fueling.
The Atlas V CCB is fueled by a extremely refined type of storable rocket-grade kerosene (often called “RP-1”), some 25,000 gallons (113,650 liters) of which had been pumped into the rocket on 20 August. The Atlas V CCB oxidizer consists of 48,800 gallons (221,850 liters) of liquid oxygen, with an extra 4,150 gallons (18,865 liters) of liquid oxygen and 12,300 gallons (55,900 liters) of liquid hydrogen destined for the Centaur’s tanks.
Tanking of this large cryogenic load—totaling over 65,000 gallons (295,500 liters)—received underway shortly after 8:40 a.m. PDT, some 2.5 hours forward of liftoff.
The method moved swiftly, though about an hour into the fueling course of groups had been obliged to troubleshoot a problem pertaining to the liquid oxygen flow-rate into the Atlas V CCB. “Tanking is underway”, tweeted ULA CEO Tory Bruno shortly earlier than 10 a.m. PDT. “Had a sticky LOX valve, but now resolved. Mighty Atlas is carbo loading.”
Because the countdown headed inside an hour earlier than launch, cryogenic loading concluded and coming into “topping”, a interval of essential replenishment because the super-chilled propellants naturally boiled away.
In the meantime, the climate remained optimum, though earlier forecasts for “unrestricted visibility” got here to nought, because the infamous Vandenberg fog rolled in. Nevertheless, it proved to not be a constraint to launch. At 10:38 p.m. PDT, the rely entered the ultimate built-in maintain at T-4 minutes, rising on time at 11:08 p.m. PDT.
The Atlas V’s Russian-built RD-180 engine roared to life at T-2.7 seconds, shortly ramping as much as 860,200 kilos (390,000 kg) on the prompt of liftoff. At present’s mission used the 401 “workhorse” of the Atlas V, numerically designated to determine its 13-foot-diameter (4-meter) payload fairing (“4”), no solid-fueled strap-on boosters (“0”) and the presence of a single-engine (“1”) Centaur higher stage.
The stack headed easily uphill and disappeared into the low-level Vandenberg murk, passing Mach 1 and experiencing peak aerodynamic stress on its airframe simply over a minute into flight. The RD-180 shut down as anticipated 4 minutes after launch and the CCB was discarded, leaving the Centaur alone to finish some of the exacting duties of its profession.
Earlier Centaurs accomplished as much as three discrete “burns” to insert their payloads into orbit and “deorbit” themselves safely on the finish of their missions. However along with Landsat-9, as we speak’s flight consists of 4 small CubeSat rideshare passengers, sponsored by NASA, the Protection Innovation Unit (DIU), the Air Drive Analysis Laboratory (AFRL) and the Missile Protection Company (MDA).
These tiny satellites are mounted on the Area Drive’s Advanced Expendable Launch Car Secondary Payload Adapter (ESPA) Flight System (EFS).
The primary Centaur burn, lasting 12 minutes, served to ship Landsat-9 into its exact orbital location, with an anticipated perigee of 414.2 miles (666.6 km) and an apogee of 422 miles (679.2 km), inclined 98.22 levels to the equator. The spacecraft separated from the Centaur just a little over an hour later at 12:32 p.m. PDT.
With Landsat-9 gone and en-route to its bold voyage, the higher stage’s process was not over. Starting half-hour after the departure of Landsat-9, a pair of Centaur burns—working for ten seconds every, with a 20-minute hole between every burn—had been executed in assist of the deployment of the 4 CubeSats. A last burn of about 25 seconds ensured that the Centaur re-enters safely on the finish of its mission.