O3b mPower 3 & 4 | Falcon 9 Block 5

Featured Image: SpaceX

Lift Off Time (Subject to change)	April 28, 2023 – 22:12 UTC | 18:12 EST
Mission Name	O3b mPower 3 & 4
Launch Provider (What rocket company is launching it?)	SpaceX
Customer (Who’s paying for this?)	SES S.A.
Rocket	Falcon 9 Block 5 Booster B1078-2
Launch Location	Space Launch Complex 40 (SLC-40), Cape Canaveral Space Force Station, Florida, USA
Payload mass	3,400 kg
Where is the satellite going?	8,000 km Medium Earth Orbit (MEO)
Will they be attempting to recover the first stage?	Yes
Where will the first stage land?	Autonomous Spaceport Droneship (ASDS) Just Read the Instructions
Will they be attempting to recover the fairings?	TBD
Are these fairings new?	TBD
How’s the weather looking?	The weather is currently 20% GO for launch (as of April 25, 2023 at 13:15 UTC)
This will be the:	– 220th Falcon 9 launch – 154th Falcon 9 flight with a flight-proven booster – 160th re-flight of a booster – 26th re-flight of a booster in 2023 – 188th booster landing – 28th launch for SpaceX in 2023 – 122nd SpaceX launch from SLC-40 – 63rd orbital launch attempt of 2023
Where to watch	Official livestream

What’s All This Mean?

SpaceX will be launching the O3b mPower 3 & 4, two communication satellites of the novel terabit-per-second O3b mPower constellation in MEO. The satellites will launch atop a Falcon 9 rocket from Space Launch Complex 40 (SLC-40), Cape Canaveral Space Force Station in Florida, USA.

O3b mPower 3 & 4 Mission

The O3b mPower is a successor of the O3b constellation operating in MEO by SES S.A. It will consist of 11 next-generation high-throughput satellites that will also work in MEO around 8,000 km above the Earth. From MEO, the constellation will cover 96% of the globe. The satellites are built and tested by Boeing and are based on its flight-proven 702 platform. Moreover, the O3b mPower 3 & 4 feature an all-electric propulsion system, custom solar arrays manufactured by Spectrolab, and the 702X software-defined payload with more than 5,000 steerable and fully-shapeable beams per satellite.

The O3b mPower 3 & 4 satellites make use of a software system called Adaptive Resource Control (ARC). ARC will provide dynamic management of service requests and available resources in orbit and on the ground. SES has been working on ARC with Kythera Space Solutions since September 2019, when they jointly announced the development.

The O3b mPower satellite system aims to provide high-performance connectivity services to multiple sectors, including government, energy, and cruise sectors, as well as telecom companies and mobile network operators. Apart from the 11 satellites, the constellation will comprise eight ground stations worldwide and dozens of software service providers. The O3b mPower’s start-of-service date is scheduled for Q3 2023 with six satellites in orbit.

What Is Falcon 9 Block 5?

The Falcon 9 Block 5 is SpaceX’s partially reusable two-stage medium-lift launch vehicle. The vehicle consists of a reusable first stage, an expendable second stage, and, when in payload configuration, a pair of reusable fairing halves.

First Stage

The Falcon 9 first stage contains 9 Merlin 1D+ sea-level engines. Each engine uses an open gas generator cycle and runs on 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 a vacuum with an ISP of 313 seconds. Due to the powerful nature of the engine and the large amount of them, the Falcon 9 first stage can lose an engine right off the pad, or up to two later in the flight, and be able to successfully place the payload into orbit.

The Merlin engines are ignited by triethylaluminum and triethylborane (TEA-TEB), which instantly burst into flames when mixed in the presence of oxygen. During static fire and launch the TEA-TEB is provided by the ground service equipment. However, as Falcon 9 first stage is able to propulsively land, three of the Merlin engines (E1, E5, and E9) contain TEA-TEB canisters to relight for the boost back, reentry, and landing burns.

Falcon 9 Booster

The booster supporting the O3b mPower 3 & 4 mission is B1078-2; as the name implies, the booster has supported one previous mission, the Crew-6. Upon successful landing, its designation will change to B1078-3.

B1078’s missions	Launch Date (UTC)	Turn Around Time (Days)
Crew-6	March 02, 2023 05:34:14	N/A

Following stage separation, the Falcon 9 will conduct two burns. These burns aim to softly touch down the booster on SpaceX’s autonomous spaceport drone ship Just Read the Instructions.

Second Stage

The Falcon 9 second stage is the only expendable part of the Falcon 9. It contains a singular MVacD engine that produces 992 kN of thrust and an ISP of 348 seconds. The second stage is capable of doing several burns, allowing the Falcon 9 to put payloads in several different orbits.

For missions with many burns and/or long coasts between burns, the second stage is able to be equipped with a mission extension package. When the second stage has this package it has a grey strip, which helps keep the RP-1 warm, an increased number of composite-overwrapped pressure vessels (COPVs) for pressurization control, and additional TEA-TEB.

Falcon 9 Fairings

The Falcon 9’s fairing consists of two dissimilar reusable halves. The first half (the half that faces 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 implies, this half plays a purely passive role in the fairing separation process, as it relies on the pneumatics from the active half.

Both fairing halves are equipped with cold gas thrusters and a parafoil which are used to softly touch down the fairing half in the ocean. SpaceX used to attempt to catch the fairing halves; however, at the end of 2020, this program was canceled due to safety risks and a low success rate.

In 2021, SpaceX started flying a new version of the Falcon 9 fairing. The new “upgraded” version has vents only at the top of each fairing half, by the gap between the halves, whereas the old version had vents placed spread equidistantly around the base of the fairing. Moving the vents decreases the chance of water getting into the fairing, making the chance of a successful scoop significantly higher.

O3b mPower 3 & 4 Countdown

All times approximate.

HR/MIN/SEC	EVENT
00:38:00	SpaceX Launch Director verifies go for propellant load
00:35:00	RP-1 (rocket grade kerosene) loading begins
00:35:00	1st stage LOX (liquid oxygen) loading begins
00:16:00	2nd stage LOX loading begins
00:07:00	Falcon 9 begins engine chill prior to launch
00:01:00	Command flight computer to begin final pre-launch checks
00:01:00	Propellant tank pressurization to flight pressure begins
00:00:45	SpaceX Launch Director verifies go for launch
00:00:03	Engine controller commands engine ignition sequence to start
00:00:00	Falcon 9 liftoff

O3b mPower 3 & 4 Launch, Landing, And Deployment

All times approximate.

HR/MIN/SEC	EVENT
00:01:12	Max Q (moment of peak mechanical stress on the rocket)
00:02:33	1st stage main engine cutoff (MECO)
00:02:36	1st and 2nd stages separate
00:02:44	2nd stage engine starts (SES-1)
00:03:23	Fairing deployment
00:06:30	1st stage entry burn start
00:06:52	1st stage entry burn complete
00:08:01	2nd stage engine cutoff (SECO)
00:08:22	1st stage landing burn start
00:08:46	1st stage landing
00:27:12	2nd stage engine starts (SES-2)
00:27:44	2nd stage engine cutoff (SECO-2)
01:49:50	2nd stage engine starts (SES-3)
01:50:18	2nd stage engine cutoff (SECO-3)
01:53:19	First O3b mPower satellite deploy
02:00:19	Second O3b mPower satellite deploys

Rocket section adapted from Trevor Sesnic