SpaceX successfully scored “three-for-three” in the small hours of Thursday morning, delivering its third Upgraded Falcon 9 booster aloft in as many months in 2017. Following hard on the heels of its first Iridium NEXT launch in January and last month’s flight of the CRS-10 Dragon to the International Space Station (ISS), the vehicle roared aloft at 2 a.m. EDT Thursday, following a slight delay, caused by concern about high upper-level winds. The launch was originally targeted for the small hours of Tuesday morning, but was scrubbed due to unacceptable weather conditions. Tonight’s flight marked the first launch from historic Pad 39A at the Kennedy Space Center (KSC) in Florida in the hours of darkness since the twilight of the Space Shuttle era.
“We truly have a tremendous team here on the Space Coast and it’s my honor to be part of this mission, supporting the commercial space industry,” said Brig. Gen. Wayne Monteith, 45th Space Wing Commander at Patrick Air Force Base and the Launch Decision Authority for tonight’s launch. “Assured access to space is a team sport here on the Eastern Range. This operation once again clearly demonstrates the successful collaboration we have with our mission partner SpaceX as we continue to shape the future of America’s space operations and showcase why the 45th Space Wing is the “World’s Premier Gateway to Space”.”
Following last Thursday’s Static Fire Test of the nine Merlin 1D+ engines of the Upgraded Falcon 9’s first stage, the vehicle was returned to a horizontal configuration for the installation of EchoStar-23. The 12,000-pound (5,500 kg) communications satellite, encapsulated within a bullet-like payload fairing, was integrated with the booster and the stack was returned to the vertical on Pad 39A early Monday. Prior to last September’s on-pad explosion of an Upgraded Falcon 9—which destroyed the $195 million Amos-6 communications satellite—new rules were implemented, requiring a customer’s payload to be installed atop the booster after the conclusion of the Static Fire Test. This protocol was first trialed in the days leading up to last month’s CRS-10 Dragon mission.
As outlined in AmericaSpace’s EchoStar-23 preview article, the opening launch attempt in the small hours of Tuesday morning was expected to bring a 70-percent likelihood of acceptable weather. This generally favorable situation was hampered by increased cloud cover over Central Florida, together with a “vigorous system” along the Gulf Coast, which threatened to trigger widespread showers and isolated thunderstorms. However, by the time the 45th Space Wing at Patrick Air Force Base issued its L-0 Weather Briefing on Monday morning the forecast had deteriorated markedly to just 40-percent favorable.
“Overcast skies, widespread showers and isolated thunderstorms are expected over Central Florida,” it was noted. Although cloud cover over KSC was expected to diminish throughout Tuesday morning’s countdown and throughout the 2.5-hour launch window, there remained the risk of violating a key mission rule which precludes flight through thick cloud. In the event of a 48-hour scrub to the next available T-0 at 1:35 a.m. EDT Thursday, weather conditions were expected to brighten significantly to 90-percent favorable, with steadily clearing skies and lightening winds.
Notwithstanding the gloomy outlook on Tuesday, efforts entered high gear for SpaceX’s third launch of 2017. With EchoStar-23 aboard, the 230-foot-tall (70-meter) Upgraded Falcon 9 was transported from the Horizontal Integration Facility (HIF) to the Pad 39A surface—a distance of about 1,300 feet (400 meters)—early Monday morning. It was then raised to the vertical, by means of the Transporter-Erector (TE). By the late afternoon, countdown operations were well underway and sunset at 7:30 p.m. EDT brought to life the possibility that this would be Pad 39A’s first night-time launch in almost seven years, since the twilight of the Space Shuttle era.
With high-level winds increasingly coming into play, any hope of flying on Tuesday was anchored to the comfortably long launch window. The Launch Conductor polled his flight control team and issued a definitive “Go” to begin loading the Upgraded Falcon 9 with liquid oxygen and a highly refined form of rocket-grade kerosene (known as “RP-1”) at 11:22 p.m. Monday. Shortly thereafter, the effort to pump RP-1 aboard the booster got underway. As detailed previously by AmericaSpace, the “densified” propellants aboard the Upgraded Falcon 9 are chilled much closer to their freezing point—the RP-1 to -7 degrees Celsius (19.4 degrees Fahrenheit) and the liquid oxygen to -207 degrees Celsius (-340 degrees Fahrenheit)—thereby affording a great performance flexibility.
However, hopes quickly evaporated. “Continuing to watch winds,” SpaceX cautioned in a 12:37 a.m. tweet, by which time the loading of liquid oxygen aboard the vehicle was also underway. With less than an hour remaining before the 1:34 a.m. opening of the launch window, the weather was classified as “Go” for most Launch Commit Criteria (LCC), but upper-level winds were not co-operating or coming within mandated bounds. According to CBS News’ Bill Harwood, the famous KSC countdown clock finally halted at T-38 minutes and 55 seconds.
Yet the formal announcement of a scrub took some time to filter down. At 1:33 a.m., the 45th Space Wing declared that Tuesday’s launch attempt had been called off; followed, at 1:36 a.m., by SpaceX confirmation. “Standing down due to high winds,” SpaceX noted. “Working toward next available launch opportunity.”
It was not immediately clear when the next attempt would be made, in spite of SpaceX having Eastern Range clearance for a backup opportunity, opening at 1:35 a.m. EDT and closing at 4:05 a.m. EDT Thursday, 16 March. In the meantime, the complex process of “safing” the Upgraded Falcon 9 got underway, as propellants and other consumables were de-tanked and countdown operations re-set to track the new launch target. At length, on Tuesday afternoon, SpaceX confirmed that it would be aiming for a revised launch attempt on Thursday, with a predicted 90-percent-favorable meteorological outlook.
“The vigorous low-pressure area along the Mid-Atlantic States is trailing a cold front through the Space Coast,” the 45th Space Wing reported in its update on Tuesday morning, shortly after the scrub. “The extensive cloud cover and isolated showers associated with the front will continue pushing south through the day today. High pressure will build in behind the front, bringing gusty northerly winds and cool air. Winds will lighten after sunset Wednesday and be within liftoff constraints by the launch window Thursday morning.” In fact, the main threat—albeit just a 10-percent threat—pertained to violating Liftoff Winds. “If this attempt is scrubbed for any reason,” noted AmericaSpace’s Launch Tracker, “then SpaceX will have to stand down for a while, as the range is booked for a Delta IV on 17-19 March, then an Atlas V is scheduled for the 21st.”
Night fell over Florida in the minutes after 7:31 p.m. Wednesday, rekindling the second opportunity for the Upgraded Falcon 9 to execute Pad 39A’s first flight in the hours of darkness for the better part of a decade. At 12:19 a.m. EDT Thursday, about 76 minutes before the scheduled opening of the launch window, the countdown clock was paused briefly, “for an unspecified reason”, according to our Launch Tracker. “The new T-0 launch time has been re-set for 2 a.m. Eastern.” The revised T-0 was confirmed by SpaceX at 12:31 a.m., and it soon became apparent that high upper-level winds were the driving concern.
A little under 80 minutes before T-0, the SpaceX Launch Conductor polled his team for a “Go/No-Go” decision to begin fueling the booster, and was greeted by a unanimous “Go” at about 12:50 a.m. After chilling down of ground-side and vehicle systems, propellant loading began with RP-1 and, by T-45 minutes, liquid oxygen was in the process of being pumped aboard the Upgraded Falcon 9. Passing T-30 minutes at 1:30 a.m., the liquid oxygen tanking into the first stage was completed and loading of the second stage got underway. This was preceded by Ground Support Equipment (GSE) purging, visibly announced by a large venting of vapor from the TE strongback.
“Not aware of any issues that may affect the launch today,” our Launch Tracker pointed out at 1:30 a.m. Apart from the weather, of course. With maximum upper-level winds originating from the west at 125 knots at 41,000 feet (12,500 meters), it was the situation at high altitude which tempered today’s otherwise smooth countdown with its 10-percent risk of a launch rule violation. Other than this risk, earlier cloudy skies began to clear, with no apparent risk of lightning or rain.
Entering the autosequence at T-10 minutes, the effort to chill down the nine Merlin 1D+ first-stage engines got underway. The Upgraded Falcon 9 transitioned to internal power and assumed primary control of all critical functions. The TE strongback—upgraded to support Upgraded Falcon 9 and future Falcon Heavy operations—was retracted by 1.5 degrees. By 1:57 a.m., just three minutes before the revised launch time, the Flight Termination System (FTS) was placed onto internal power and armed. Propellants aboard both stages were secured shortly thereafter and a final “Go for Launch” was declared at 1:58 a.m.
With a minute to go, the vehicle’s on-board computers entered “Startup” at T-60 seconds and the Range Operations Co-ordinator (ROC) declared “Range Green”. Both stages were confirmed as fully pressurized for flight at T-20 seconds and the nine Merlins ignited at T-3 seconds, pumping 1.5 million pounds (680,000 kg) of thrust onto Pad 39A. As intended, the upgraded TE strongback completed a 35-degree retraction from the vehicle shortly ahead of T-0, providing sufficient clearance for liftoff.
Launch took place precisely on 2 a.m. EDT. Just like the very first nocturnal launch from Pad 39A—that of Apollo 17, way back in December 1972—the Upgraded Falcon 9 literally turned night into day at the Kennedy Space Center, blazing into the darkness. Passing the area of maximum aerodynamic turbulence a minute into the flight, the nine Merlins burned for a little more than 2.5 minutes, shutting down at 163 seconds. A few seconds thereafter, the first stage was jettisoned, allowing the Merlin 1D+ Vacuum engine of the second stage to begin its task of boosting EchoStar-23 to Geostationary Transfer Orbit (GTO).
And at this stage, the flight profile differed quite significantly from most previous missions. Tonight’s Upgraded Falcon 9 was visibly distinct in that it lacked the four landing legs, deployable hypersonic grid fins and other support structures necessary to execute a controlled touchdown, either on the Autonomous Spaceport Drone Ship (ASDS) or at Landing Zone (LZ)-1 at the Cape.
The mass of the payload, which reaches about 12,000 pounds (5,500 kg), coupled with the high orbit, required maximum performance from the booster and left very little propellant in reserve to execute the requisite boost-back and landing “burns”. In fact, the required velocity of this mission was expected to reach Mach 30, equivalent to more than 23,000 mph (37,000 km/h). As such, this was the first “expendable” Falcon 9 launch since April 2015, when an earlier-generation v1.1 vehicle transported the heavyweight TurkmenAlem-52/MonacoSat payload to GTO.
A few seconds shy of three minutes into tonight’s ascent, the Merlin 1D+ Vacuum ignited, producing 210,000 pounds (92,250 kg) of propulsive yield. Shortly afterwards, the bulbous payload fairing was jettisoned, exposing EchoStar-23 to the near-total vacuum environment of space for the first time. The restartable Merlin 1D+ Vacuum was tasked with two discrete “burns”, the first of which ran for almost six minutes and ended with Stage Engine Cutoff (SECO-1) at 8.5 minutes after liftoff. This established the vehicle in an initial parking orbit. It then entered a protracted coast phase of almost 18 minutes, before the engine restarted a little over 26 minutes after departing KSC.
This burn was significantly shorter, lasting just 60 seconds, and established the proper conditions for the deployment of EchoStar-23 at 34 minutes into the flight. “Final second-stage engine cutoff nominal,” SpaceX tweeted at 2:27 a.m. “Preparing to deploy satellite.” That deployment into GTO was confirmed at 2:35 a.m. and the satellite will now enter up to three months of commissioning at 86.4 degrees West longitude, before it is maneuvered into its planned operational “slot” at 44.9 degrees West to provide Direct-to-Home (DTH)/Direct Broadcast Satellite (DBS) services under contract to the Brazilian Government.
Tonight’s launch also marked the final Falcon 9 to utilize ground-based mission flight control personnel and equipment in the mission control center, according to the 45th Space Wing. “All future SpaceX rockets will utilize an Autonomous Flight Safety System, which replaces the ground-based mission flight control personnel and equipment with on-board Positioning, Navigation and Timing sources and decision logic,” it explained. “The benefits of AFSS include increased public safety, reduced reliance on range infrastructure, reduced range spacelift cost, increased schedule predictability and available, operational flexibility and launch-slot flexibility.” The AFSS infrastructure was first trialed during last month’s CRS-10 launch.