Featured image source: SpaceX Lift Off Time May 20, 2023 – 13:16 UTC | 09:16 EDTMission NameIridium-9 & OneWeb 19 Launch Provider
(Which rocket company launched it?)SpaceXcustomer
(Who paid for this?) Iridium and OneWebRocket
Falcon 9 Block 5 B1063-11; 35.27 days turnaround timeLaunch SiteSpace Launch Complex 4E (SLC-4E), Vandenberg Space Force Base, California, USAPayload mass ~7,000 kg (~15,500 lb) (Iridium: 5 x 4,800 k8; OneWeb: 16 x 147.7 kg plus deployment hardware)Wk Did the satellites fly?Polar low earth orbitDid they try to recover the first stage?YesWhere did the first stage land?~600km below range on Of course I still love youDid they try to recover the fairings?Yes, the disguises were salvaged from GO Beyond, were these disguises new? One half of the fairing flew for the sixth time and the other for the third time. This was the: – 225th launch of the Falcon 9
– 161st Falcon 9 flight with a flight-proven booster
– 167th repeat flight of a booster rocket
– 33rd repeat flight of a booster rocket in 2023
– 193rd booster landing
– 119th landing in a row (a record)
– 34th launch for SpaceX in 2023
– 42nd SpaceX launch of SLC-4E
– 72nd orbital launch attempt in 2023Where to watchOfficial rerun How did it go?
SpaceX successfully launched 15 OneWeb internet communications satellites (and a single test satellite) on its Falcon 9 Block 5 rocket. Alongside these satellites, Iridium launched five of its next-generation Iridium 9 satellites. This mission launched from Space Launch Complex 4 East at Vandenberg Space Force Base in California, USA, and placed satellites in low Earth polar orbit.
This mission was the second mission of SpaceX’s redesign of the second stage Merlin vacuum jet, used only on lower powered missions. This shorter, and therefore less powerful, nozzle reduces the number of RTLS (Return to Launch Site) missions SpaceX can launch. That’s why this mission landed on one of SpaceX’s drone ships.
What is the constellation of Iridium?
The Iridium 9 satellites will expand the current Iridium constellation, most of which was launched by SpaceX between 2017 and 2019, replacing several satellites. The constellation has 66 operational satellites, nine in-orbit spares and six ground spares.
Iridium’s constellation provides L-band voice and data to satellite phones around the world. The satellites are in low Earth orbit at an altitude of 781 km and have an inclination of 86.4° – this near-polar orbit allows them to cover the entire globe. Each satellite has a launch mass of 689 kg and features two extendable solar panels and batteries.
What is OneWeb?
OneWeb is a planned satellite Internet constellation with the goal of covering the entire world with Internet. Similar to SpaceX’s Starlink, the OneWeb constellation aims to deliver mid-latency Internet in locations where ground-based Internet is unreliable or unavailable.
OneWeb plans to have 648 satellites in its constellation, providing the 600 satellites needed for global coverage, plus another 48 spare satellites in orbit in the event one satellite fails. These satellites are in a low-Earth polar orbit of 1,200 km, which is significantly lower than the global internet services available today. The current satellite internet solutions orbit in a geostationary orbit at an altitude of 35,786 km above the earth. However, the orbit of the OneWeb satellites is still significantly higher than the ~550km orbit used by SpaceX’s Starlink satellites. OneWeb anticipates that the final 648 satellite constellation will offer download speeds of around 50 Mbps.
Final orbits of the 648 satellite constellation (Source: Airbus)
The constellation consists of 18 orbital planes with 36 satellites in each plane. However, in May 2020, OneWeb filed an application with the FCC, requesting that it increase the size of its constellation to 48,000 satellites. OneWeb has also announced that the second generation of the OneWeb network will be a global navigation satellite system (GNSS) like GPS.
What is a OneWeb satellite?
Each OneWeb satellite has a compact design and a mass of 147.5 kg. The satellites are each equipped with a Ku-band antenna operating between 12 and 18 GHz. An interesting note is that these satellites will use a slightly abnormal frequency, avoiding interference with satellites in geostationary orbit.
The OneWeb satellites were built by OneWeb Satellites, a joint venture between OneWeb and Airbus.
The satellites are designed to safely deorbit after 25 years. This is of concern to many, however, as this orbital region is already the most congested with space debris.
Artist’s rendering of a OneWeb satellite (Source: TechCrunch) OneWeb’s return
In March 2020, OneWeb filed for Chapter 11 bankruptcy, laying off most of its employees. However, OneWeb was able to maintain operations of the 74 satellites currently in orbit. In November 2020, the UK government and Bharti Enterprises invested over $1 billion in OneWeb with the aim of completing the constellation.
As if those problems weren’t enough, as a result of new European sanctions earlier in the year, OneWeb was unable to launch its satellites on the Soyuz vehicle – the rocket that launched the first 13 OneWeb missions. Instead, on April 20, 2022, OneWeb announced the launch of the GSLV Mk III and Falcon 9.
What is Falcon 9 Block 5?
The Falcon 9 Block 5 is SpaceX’s semi-reusable medium-lift two-stage launch vehicle. The vehicle consists of a reusable first stage, an expendable second stage and, when in the payload configuration, a pair of reusable fairing halves.
The Falcon 9 first stage contains 9 Merlin 1D+ sea level engines. Each engine utilizes an open circuit gas generator and is fueled by RP-1 and liquid oxygen (LOx). Each engine produces 845 kN of thrust at sea level with a specific impulse (ISP) of 285 seconds and 934 kN in vacuum with an ISP of 313 seconds. Due to the powerful nature of the engines and their large number, it is possible for the Falcon 9 first stage to lose one engine right off the launch pad or up to two later in flight and successfully place the payload in orbit.
The Merlin engines are ignited with triethyl aluminum and triethyl borane (TEA-TEB) which ignite instantaneously when mixed in the presence of oxygen. During static fire and takeoff, the TEA-TEB is provided by ground service equipment. However, because the Falcon 9 first stage is capable of thrust landing, three of the Merlin engines (E1, E5, and E9) contain TEA-TEB canisters that are re-ignited for reverse thrust, reentry, and landing can.
The Falcon 9 second stage is the only expendable part of the Falcon 9. It contains a unique MVacD engine that produces 992 kN of thrust and an ISP of 348 seconds. The second stage is capable of multiple burns, allowing the Falcon 9 to launch payloads into different orbits.
For missions with many burns and/or long wait times between burns, the second stage can be equipped with a Mission Extension Package. If the second stage has this package, it will have a gray stripe that helps keep the RP-1 warm, an increased number of composite-overwrapped pressure vessels (COPVs) for pressure regulation, and additional TEA-TEB.
Falcon 9 Block 5 Launches on Starlink V1.0 L27 Mission (Source: SpaceX) Falcon 9 Booster
The booster supporting this mission was B1063-11. As the name suggests, the booster had supported ten previous missions.
B1063 MissionsStart Date (UTC)Processing Time (days)Sentinel-621. Nov 2020 17:17N/AStarlink V1.0 L2826. May 2021 18:59186.07DART24. November 2021 06:21181.47 Starlink Group 4-11February 25.2022 17:1262.45 Starlink Group 4-13 May 13, 2022 22:07108.20 Starlink Group 3-1 July 11, 2022 01:3958.15 Starlink Group 3- 4 Aug 31, 2022 05:4051.17 Starlink Group 4-31 Oct 28, 2022 01:1457.82 Star Link Group 2-5 Feb 17, 2023 19:12112.75 Transporter-7 Apr 15, 2023 6:48 UTC56. 48Iridium-9 and OneWeb 19 19 May 2023 13:1934.27
After launch, the Falcon 9 launcher performed two burns. These burns gently staged the booster of “Of Course I Still Love You”.
Falcon 9 lands on Of course I still love you after launching Bob and Doug’s Falcon 9 disguises (Source: SpaceX)
The Falcon 9 fairing consists of two different reusable halves. The first half (the half facing away from the transport erector) is called the active half and houses the pneumatics for the separation system. The other fairing half is called the passive half. As the name suggests, this half plays a purely passive role in the fairing separation process, as it relies on the pneumatics of the active half.
Both fairing halves are equipped with cold gas engines and a parafoil, which serve to gently land the fairing half in the sea. SpaceX used to attempt to capture the fairing halves, but in late 2020 that program was canceled due to safety concerns and a low success rate. On Iridium-9 and OneWeb 19, SpaceX tried to recover the fairing halves from the water with its salvage ship GO Beyond.
In 2021, SpaceX began flying a new version of the Falcon 9 fairing. The new “improved” version has vents only at the top of each fairing half, in the gap between the halves, while the old versions had vents evenly spaced around the base of the fairing. Moving the vents reduces the chance of water entering the fairing, significantly increasing the chance of a successful shovel.
A Falcon 9 Active Half Fairing (Source: Greg Scott) Passive Falcon 9 Half Fairing (Source: Greg Scott) Half of the fairing is removed. Go. Navigator. (Image credit: Lupi) A passive fairing half is unloaded by Shelia Bordelon after the Starlink V1.0 L22 mission. (Image credit: Kyle M) Iridium 9 and OneWeb 19 countdown
All times are approximate
HR/MIN/SECEVENT00:38:00SpaceX launch director verifies fuel charge release.00:35:00RP-1 (rocket kerosene) loading.00:35:001. Level LOX (liquid oxygen) is loaded. 00:16:002. Loading stage LOX.00:07:00Falcon 9 begins engine cool down before launch. 00:01:00Flight computer instructed to begin final pre-takeoff checks. 00:01:00Pressurization of the fuel tank to flight pressure begins. 00:00:45SpaceX launch director checks launch readiness.00:00:03Engine control commands engine firing sequence to begin00:00:00Falcon 9 launch Sun: