SpaceX has launched with the debuting of an upgraded payload fairing for the Falcon 9 rocket during Spain’s Paz satellite lofting from Vandenberg Air Force Base on Thursday. The launch, scrubbed on Wednesday due to Upper Level Winds, also carried the first demonstration satellites for SpaceX’s own satellite internet constellation. Launch occurred at an instantaneous launch opportunity at 06:17 Pacific Time (14:17 UTC).
Paz is a radar imaging satellite which will be operated by Spanish company Hisdesat. The spacecraft will provide day and night, all-weather imaging capabilities for Hisdesat’s customer, Spain’s Ministry of Defence.
The launch of Paz had previously been scheduled to take place last Sunday. However, SpaceX announced a delay on Saturday to the next available date: Wednesday. That attempt was scrubbed due to Upper Level Winds being just above the acceptable limits. However, Thursday’s countdown was issue-free.
SpaceX confirmed that the rocket would fly with an upgraded payload fairing and that the reason for the initial delay was to give additional time for checkouts on this part of the vehicle. This was unrelated to the weather scrub on Wednesday.
The upgrade is understood – although unconfirmed by SpaceX – to be Fairing Version 2 – or “Fairing 2.0” – a new version of the protective shroud expected to improve its survivability for post-launch recovery attempts, and to be reusable on future missions.
Mounted at the top of Falcon 9’s second stage, the payload fairing maintains the rocket’s aerodynamic profile and protects the payload from Earth’s atmosphere during the initial stages of the ascent towards space. It is split into two halves, which separate down the middle.
The fairing – which has an estimated cost of about six million dollars – is discarded to save weight once the rocket reaches space. With traditional expendable rockets, the fairing will burn up in the atmosphere or fall downrange of the launch site.
Having achieved incredible success with recovering and re-using Falcon 9’s first stage, SpaceX has now turned their attention to doing the same the fairing. The company has already achieved some success during testing with Falcon 9’s standard fairing – including bringing part of the fairing back to shore after a controlled landing at sea during the SES-10 launch last April.
During a press conference following the recent Falcon Heavy launch, SpaceX founder and CEO Elon Musk described developing the recovery process for the fairing as having proven “surprisingly difficult”, but that he expected SpaceX to solve the remaining problems within six months.
The launch was expected to see another attempt to return at least half of the fairing to Earth. After separation, one or both sections of the fairing will reorient themselves for reentry into the atmosphere.
As the fairing halves descend, they will deploy parachutes to slow their fall and guide themselves towards a recovery boat which will be maneuvered into position underneath.
The ship, named Mr. Steven, was outfitted with four large metal arms for recovery operations, which Elon Musk described as a “giant catcher’s mitt”. Although Mr. Steven put to sea in support of December’s Iridium-NEXT launch, it has been seen for the first time with a net suspended between the arms ahead of the launch.
This suggested an attempt to land half of the fairing aboard Mr. Steven was on the cards. Mr. Steven left the Port of Los Angeles at 11:39 Pacific Time (19:39 UTC) on Tuesday.
The test was unsuccessful in that Mr. Steven didn’t catch the fairing, but the catch only missed by a few hundred meters, according to Elon Musk. The fairing did survive, however.
— Michael Baylor (@nextspaceflight) February 22, 2018
Although SpaceX’s attempt to recover part of the fairing is another new effort from the company, one thing that was not to be recovered was the rocket’s first stage – or core. Although the payload is not sufficiently heavy to require a fully-expendable rocket, the core would not be suitable for reuse on any future launches so the call was to dispose of by allowing it to fall into the Pacific Ocean.
The core was outfitted with grid fins, but not landing legs, which suggested that SpaceX may still use it to perform a controlled descent into the water. During last month’s GovSat-1 launch from Cape Canaveral an expendable first stage was used to test a new landing burn technique and unexpectedly survived a soft landing in the Atlantic – although it was subsequently scuttled as it could not safely be returned to shore.
However, it appeared this booster was always destined for a destructive return and discarded, per later comments from SpaceX.
The core that powered this mission was B1038.2, a flight-proven – or previously-flown – booster which was also used in last August’s launch of Taiwan’s Formosat-5 satellite. B1038 was the final Falcon 9 first stage to be built to the Block 3 specification, before an upgraded Block 4 version was introduced.
As well as being the last Block 3 core to be built, B1038 was also expected to be the last Block 3 to fly. Following the debut of the improved Block 4 version with last August’s CRS-12 launch, all subsequent new cores have adhered to this standard. In order to ensure reliability SpaceX has opted not to fly block 3 cores more than twice, and B1038 was the last remaining block 3 core yet to make its second flight.
The primary payload is Paz, a radar imaging satellite that was being carried for Spain’s Hisdesat. Paz carries an X-band synthetic aperture radar (SAR) system, intended to form one half of the Programa Nacional de Observación de la Tierra por Satélite (PNOTS), or National Programme for Earth Observation by Satellite. A second satellite, Ingenio, carries an optical imaging payload. This has not yet been manifested for launch.
Paz – Spanish for “peace” – was originally named SEOSAR. It was built by Airbus Defence and Space (Spain), which absorbed the original prime contractor, EADS CASA Espacio, in 2009. The satellite is built around the AstroBus platform and is based on two earlier radar imaging satellites – TerraSAR-X and TanDEM-X – which were built by EADS Astrium for Germany’s national space center. TerraSAR-X has been in orbit since June 2007, while TanDEM-X was launched three years later, and both satellites have now exceeded their five-year design lives but remain in service.
Paz will be co-located with these two spacecraft in a sun-synchronous low Earth orbit, enabling combined observations between the missions. The target orbit for the Paz mission is approximately circular, at an altitude of 514 kilometers (319 miles, 278 nautical miles) and an inclination of 97.44 degrees, with a local time of ascending node (LTAN) of 18:00. This orbit allows the satellite to revisit a point on the planet’s surface every 167 orbits, or 11 days.
The Paz satellite has a mass at launch of 1,341 kilograms (2,956 pounds), and a dry mass (without fuel) of 1,282 kilograms (2,826 lb). Paz is designed to operate for at least seven years, although Hisdesat is hopeful that its mission can be extended to ten years. It has a hexagonal prism shape, measuring five meters in length and 2.4 meters in diameter (16 by 7.9 feet), with a surface-mounted solar panel equipped with triple-junction gallium arsenide cells providing 850 watts of power.
The spacecraft’s imaging payload, PAZ-SAR, incorporates a 4.8-by-0.7-metre (15.7-by-2.3-foot) antenna. The x-band radar imaging payload will operate at a wavelength of 3.1 centimeters (1.2 inches), or a frequency of 9.65 gigahertz. It can operate in strip-mapping, scanning, spotlight and high-resolution spotlight modes. In high-resolution spotlight mode, the satellite can achieve sub-meter resolutions imaging 25-square-kilometer (9.65-square-mile) regions on the surface.
The launch marked the end of a long road to the launch pad for Paz, which was originally to have been launched by Russia’s ISC Kosmotras. Like TerraSAR and TanDEM, the satellite was to have flown aboard a Dnepr rocket, with the launch to have taken place from the Dombarovsky missile base near the Russian town of Yasny. Dnepr launches were stopped after 2015: the rocket was based on decommissioned R-36M missiles, whose manufacturers – the Yuzhnoye design bureau and Yuzhmash manufacturing plant – had been located in Ukraine since the fall of the Soviet Union.
The fallout from Russia’s 2014 military intervention in Ukraine and its annexation of Crimea led to planned Dnepr launches being delayed and now Dnepr looks unlikely ever to fly again. After canceling their contract with Kosmotras in 2016, Hisdesat announced in early 2017 that SpaceX would be launching Paz aboard a Falcon 9.
Paz was joined aboard Falcon 9 by MicroSat-2a and 2b, a pair of 400-kilogram (880 lb) demonstration satellites for SpaceX’s planned Starlink internet constellation. The satellites are the first prototypes in a fleet which may consist of up to 12,000 spacecraft.
SpaceX first announced Starlink in early 2015. The project will use satellites in place of traditional infrastructure to help provide high-speed broadband internet access around the world. SpaceX’s filings with the US Federal Communications Commission indicate that the constellation will be used for fixed satellite services (FSS), such as backhaul for transmitting data around the globe. The space-based architecture could be used to help bring faster internet access to more remote regions of the planet in the future.
The Starlink constellation will consist of Ka- and Ku-band satellites orbiting at an altitude around 1,200 kilometers (750 miles, 650 nautical miles) and V-band satellites orbiting considerably lower – at around 340 kilometers (210 miles, 180 nautical miles). SpaceX aims to have Starlink fully operational by 2024, with the final operational constellation expected to contain 4,425 satellites across 83 planes in the higher orbit, with a further 7,518 satellites in the lower orbits.
The MicroSat-2a and 2b demonstration satellites carry Ku-band payloads. They were expected to be deployed into approximately the same orbit as Paz.
First two Starlink demo satellites, called Tintin A & B, deployed and communicating to Earth stations pic.twitter.com/TfI53wHEtz
— Elon Musk (@elonmusk) February 22, 2018
In showing footage of their deployment, Elon Musk also revealed their names: Tintin.
For this mission, Falcon lifted off from Space Launch Complex 4E at California’s Vandenberg Air Force Base. Originally built as part of the US Navy’s Point Arguello launch site, SLC-4E became part of the adjacent Vandenberg Air Force Base when the two launch sites merged in 1964.
The pad saw its first launch a few weeks after the merger, with an Atlas SLV-3 Agena-D deploying a KH-7 GAMBIT reconnaissance satellite. The pad was used by Atlas-Agena vehicles until June 1967, when the Atlas-Agena ended regular launches from the West Coast.
Four years later the pad returned to service with the maiden flight of the Titan III(23)D rocket. SLC-4E was the only pad at Vandenberg to support the heavy-lift versions of Titan, which continued to use the pad until October 2005, when the Titan rocket family’s final flight – made by a Titan IV(404)B – lifted off from SLC-4E.
A second pad at Space Launch Complex 4, SLC-4W, was also built as part of Point Arguello. It initially supported Atlas launches before transitioning to smaller versions of the Titan rocket – the Titan IIIB and later Titan II(23)G. SpaceX leased both pads from the US Air Force, tearing down the Titan launch facilities and configuring SLC-4E for Falcon 9 launches.
SLC-4W has been converted into a landing pad to support future return-to-launch-site (RTLS) booster recovery. However, this has yet to be attempted at Vandenberg.
Falcon 9 is a two-stage rocket which first flew in 2010. This mission was its forty-ninth launch – not including the Falcon Heavy that flew earlier this month, which is based on the Falcon 9 but with two additional first-stage boosters strapped either side of a reinforced central core.
Falcon 9 has completed its forty-eight previous missions with only one failure – during June 2015’s launch of the CRS-7 resupply mission to the International Space Station. Another Falcon 9 was lost in September 2016 during fuelling ahead of a static fire ground test, two days ahead of its planned launch.
Falcon’s first stage is powered by nine Merlin-1D engines, which burn RP-1 kerosene propellant oxidized by subcooled liquid oxygen. The process of subcooling the oxidizer was introduced in late 2015 with the Falcon 9 v1.2, or “Full Thrust”, revision of the rocket, which will be used in its Block 3 form for the launch. It is the third major revision of the Falcon 9 design, after the original version – now retrospectively known as v1.0 – and the Falcon 9 v1.1.
The nine engines ignite three seconds before Falcon’s planned liftoff. These build up to full thrust and undergo checkout before the rocket is released to begin its ascent towards orbit. Seventy-seven seconds after liftoff Falcon passed through the area of maximum dynamic pressure, or Max-Q.
The first stage – Core 1038 – burned for the first two minutes and 29 seconds of the flight before reaching main engine cutoff, or MECO. The nine engines shut down, with stage separation occurring four seconds later. The second stage’s single Merlin Vacuum (MVac) engine – a version of the Merlin-1D optimized to operate in the vacuum of space – ignited seven seconds after stage separation.
Although SpaceX has confirmed that Core 1038 was not to be recovered, and the stage is not equipped with landing legs, it was sporting grid fins. The stage may perform some or all of the three post-separation burns that are conducted on missions where the stage is recovered – possibly guiding itself to a soft landing in the Pacific Ocean that would allow SpaceX to experiment with different landing techniques for future flights. The second stage continued on to orbit with its payload.
For this launch, the second stage only needed to make a single burn to place Paz into orbit. This burn lasted six minutes and eighteen seconds, with separation of Falcon’s payload fairing taking place sixteen seconds after ignition. Two minutes after the end of the burn, Paz separated from the upper stage to begin its mission. SpaceX had not confirmed at what point in the mission the two Starlink satellites will separate.
This launch was the first for SpaceX since their first test launch of the Falcon Heavy rocket at the beginning of the month.
The heavy-lift vehicle, based on the Falcon 9, performed successfully and placed Elon Musk’s old Tesla Roadster car into a heliocentric orbit that will take it out as far as the asteroid belt.
Paz was SpaceX’s fourth launch of 2018, following the Falcon Heavy mission and two Falcon 9 flights in January that carried the Zuma spacecraft for Northrop Grumman and GovSat-1 for LuxGovSat and its parent company SES.
The Paz mission was the first of two SpaceX launches in February with Spanish payloads. The second, which will carry the HispaSat 30W-6 communications satellite into geostationary transfer orbit, is due to lift off from Cape Canaveral Air Force Station in the early hours of next Sunday morning.