SpaceX’s Falcon 9 rocket has conducted its third flight of the year on Thursday, following a scrub due to high winds on Tuesday. The launch carried a commercial communications satellite into geosynchronous transfer orbit. The launch took place from Launch Complex 39A at the Kennedy Space Center in Florida.
Falcon 9 Launch:
The launch carried the EchoStar XXIII satellite into orbit for EchoStar Corporation.
With a mass of around 5,500 kilograms (12,000 lb), EchoStar XXIII was the heaviest geosynchronous payload yet launched by the Falcon 9, requiring the rocket to fly in a fully-expendable configuration.
By eliminating the attempt to recover the rocket’s first stage, which has been a feature of SpaceX’s recent launches, the rocket does not need to conserve fuel for first stage landing maneuvers and also saves weight through the elimination of hardware carried to support the landing – including the landing gear and grid fins.
EchoStar XXIII was constructed by Space Systems Loral (SSL), based on the SSL-1300 bus. The satellite was originally constructed as EchoStar XIII, or CMBStar, which was intended to be used under a partnership between EchoStar and the Chinese government to provide s-band mobile video broadcasting during the 2008 Summer Olympics.
The program was abandoned in April 2008, after construction was complete, when it became clear the satellite would not launch in time for the Olympics – although the reason stated for the cancellation was that performance specifications had not been met.
The EchoStar XXIII satellite was ordered in 2014, to reuse the spacecraft which had been constructed for the earlier mission. The large antenna which would have served mobile users of the EchoStar XIII satellite has been replaced with four Ku-band antennae with thirty-two transponders, while the satellite is also able to offer S-band and Ka-band communications.
The satellite has a design life of fifteen years and will begin its service life in an orbital slot at a longitude of 45 degrees West. However, it is able to operate in any of EchoStar’s eight geosynchronous slots allotted to Ku-band broadcasting satellites.
The launch took place from the historic Launch Complex 39A (LC-39A) at NASA’s Kennedy Space Center in Florida.
Built in the 1960s for the Apollo program, LC-39A served as the prime launch pad for manned Lunar missions. Every Apollo mission to visit the moon, except for Apollo 10, lifted off from LC-39A atop a Saturn V rocket – the pad was also used for the Saturn V’s first two unmanned launches, Apollo 4 and Apollo 6, the Earth-orbit Apollo 9 mission, and to launch the Skylab space station aboard a modified two-stage version of the Saturn V.
Following the Skylab launch, LC-39A was converted to serve the Space Shuttle, which made its maiden flight from the pad on 12 April 1981. The Space Shuttle flew eighty-two of its 135 missions from Launch Complex 39A, with its other flights being made from Complex 39’s other pad, LC-39B.
Since the end of the Space Shuttle program a third pad has been added to the launch complex; LC-39C is located within the perimeter of pad 39B, and is designed to accommodate smaller rockets. It has not yet been used for a launch.
The final Space Shuttle launch, STS-135, occurred from LC-39A on 8 June 2011. NASA announced in 2014 that it had agreed to lease pad 39A to SpaceX for twenty years, with SpaceX converting the facility to service its Falcon 9 rocket as well as the future Falcon Heavy.
A new hangar was constructed at the base of the pad’s ramp, replacing the role of the Vehicle Assembly Building (VAB) in integrating rockets.
In contrast to Saturn and the Space Shuttle, which were stacked vertically atop a mobile platform and then rolled to the pad atop a crawler transporter vehicle, Falcon is assembled horizontally and then erected on the launch pad.
The launch of EchoStar XXIII is the second for SpaceX from the Kennedy Space Center, following the Falcon 9’s inaugural mission from the site last month.
EchoStar XXIII was the first commercial geosynchronous satellite to be launched from Kennedy since January 1986 – when Space Shuttle Columbia deployed the Satcom K1 spacecraft, with the aid of a PAM-D2 upper stage, during the last successful Shuttle mission before the loss of Challenger.
Before Challenger, commercial satellites – along with other payloads for NASA and the US military – were frequently deployed during Space Shuttle missions.
Beginning with Columbia’s STS-5 mission in 1982, a total of twenty commercial communications satellites were deployed. The Shuttle would carry the satellites into low Earth orbit, with perigee kick motors such as the Payload Assist Module (PAM) boosting them into geosynchronous transfer orbit.
Although commercial satellite deployments were halted after Challenger, NASA and the military continued to fly satellites aboard the Shuttle into the 1990s.
The Space Shuttle’s final geostationary payload was NASA’s TDRS-G – later TDRS-7 – communications satellite, which Discovery deployed with the aid of an Inertial Upper Stage (IUS) in July 1995’s STS-70 mission.
The final Shuttle mission dedicated to satellite deployment was STS-93, conducted by Columbia in July 1999, which placed the Chandra X-Ray Observatory into a highly elliptic orbit – again using an IUS.
The EchoStar launch was the first from LC-39A not in support of the International Space Station since Space Shuttle Atlantis flew the final Hubble Space Telescope servicing mission, STS-125, in May 2009.
The launch was the ninety-sixth from Launch Complex 39A, the 155th from Launch Complex 39 and the 156th overall from the Kennedy Space Center.
The mission was the thirty-first flight of the Falcon 9 rocket, which made its debut with a test launch in June 2010.
The first five launches used a configuration which has retrospectively been known as Falcon 9 v1.0, with the sixth launch onwards introducing the v1.1 configuration which stretched both the first and second stages of the rocket, rearranged the first stage engines from a square to octagonal formation and upgraded the vehicle’s engines.
The current configuration, known informally as the Falcon 9 Full Thrust or Falcon 9 v1.2, further stretched the vehicle’s second stage, introduced supercold liquid oxygen – which is denser than the liquid oxygen used previously, allowing a greater mass of oxidizer to be carried within the same tank volume – and uprated engines.
The Falcon 9 was designed with reusability in mind; where mission requirements allow, the first stage is equipped with landing gear and makes a series of engine burns to guide itself back to Earth after separation.
A major goal of the Full Thrust configuration was to increase the rocket’s performance so that an attempt to recover the first stage could be made on nearly all missions, either aboard an Autonomous Spaceport Drone Ship (ASDS) downrange, or where the mission’s performance margin is sufficient by returning to the launch site.
SpaceX has achieved in increasing level of success with recovery attempts; recovering eight first stages from thirteen attempts.
The mission did not include a landing attempt, as delivering EchoStar XXIII into geosynchronous transfer orbit required too much of the rocket’s performance. The rocket flew without the legs and grid fins used in landing attempts, with the spent first stage falling into the Atlantic Ocean once it completed its burn.
Fuelling of the Falcon 9 for the launch began seventy minutes before liftoff with loading of RP-1 propellant. A poll eight minutes beforehand verified that controllers were happy to proceed into this stage of the countdown. Oxidizer loading began forty-five minutes in advance of launch.
Most of the countdown’s visible activity occurred in the final ten minutes. At the seven-minute mark chilldown of the vehicle’s engines began. Shortly afterwards the strongback – the structure used to transport the rocket to the launch pad, erect it and to provide umbilical connections, retracted by a degree and a half as a test ahead of its full retraction as the rocket lifts off.
Final approval to launch was given by the US Air Force’s Range Control Officer (RCO) and SpaceX’s launch director at the 120-second and 90-second marks in the countdown respectively.
Three seconds before launch, the first stage’s nine Merlin 1D engines ignited, with the rocket lifting off as the countdown reached zero. As Falcon began its climb away from the pad, the strongback fell away from the vehicle to its retracted position.
Falcon 9 passed through the area of maximum dynamic pressure – or Max-Q – where the vehicle experiences peak aerodynamic stress, seventy-six seconds after liftoff. The first stage burned for two minutes and forty-three seconds before cutoff, or MECO.
Four seconds after MECO the spent stage was jettisoned, with second stage ignition taking place eight seconds after stage separation. The payload fairing separated from the nose of the vehicle forty-eight seconds into the second stage burn.
To deploy EchoStar XXIII, the Falcon 9’s second stage was called upon to make two burns. The first of these lasted five minutes and 36 seconds, establishing an initial parking orbit.
Following a 17-minute, 48-second coast phase the second stage restarted its vacuum-optimised Merlin-1D engine for a sixty-second second burn. The end of this burn, at 27 minutes and 19 seconds mission elapsed time, concluded powered flight.
Spacecraft separation occurred six minutes and 41 seconds later, thirty-four minutes after liftoff.
The third mission for SpaceX in 2017, the launch followed last month’s CRS-10 Dragon mission to the International Space Station and January’s deployment of ten Iridium communications satellites.
The Iridium launch, conducted from Vandenberg Air Force Base in California, marked Falcon’s return to flight after a Falcon 9 exploded on its launch pad last September during fuelling for a test firing ahead of the planned launch of the Amos 6 satellite, which was destroyed in the explosion.
The launch marks the start of a busy two weeks on Florida’s Space Coast, with a Delta IV launch from the Cape Canaveral Air Force Station scheduled to deploy the WGS-9 communications satellite and an Atlas V slated to carry Orbital ATK’s next Cygnus spacecraft, the SS John Glenn, to the International Space Station.
The next mission for SpaceX is currently scheduled for 27 March, with another Falcon 9 from LC-39A deploying the SES-10 satellite. That launch is expected to be the first to re-fly a first stage recovered from a previous mission.
EchoStar’s next launch is expected to be conducted by International Launch Services at the end of April; a Proton-M rocket with a Briz-M upper stage will carry the EchoStar XXI satellite into orbit.
(Images via SpaceX and L2 Historical. To join L2, click here: https://www.nasaspaceflight.com/l2/)