After successfully conducting back-to-back flights from their recently-inaugurated US launch site, Rocket Lab returned to New Zealand for its second mission in March. Liftoff of “The Beat Goes On” mission took place on Friday, March 24 at 10:14 PM NZDT (09:14 UTC).
This mission marked the 35th total flight of the California-based company’s venerable two-stage Electron launcher, and the third mission launched by Rocket Lab so far in 2023. It was also the first flight of the year from Rocket Lab Launch Complex 1, following a four-month-long lull in action since the launch of “Catch Me If You Can” in November 2022.
Launch Complex 1, which sits at the southern tip of the Māhia Peninsula in New Zealand, was purpose-built to host launches to high-inclination orbits (such as Sun-synchronous missions) and features two dedicated pads — LC-1A and LC-1B, respectively — to support increasing launch rates. “The Beat Goes On” mission is due to fly from LC-1B, which will see its seventh launch since its introduction in February 2022.
“The Beat Goes On” serves as a dedicated mission for BlackSky, a subsidiary of mission management services provider Spaceflight Industries Inc. The launch will be the sixth and final flight of a multi-launch agreement that was signed in 2021 by BlackSky and Rocket Lab and that will see a total of 11 satellites launched.
For this mission, Electron carried two BlackSky Gen-2 spacecraft that form part of a growing constellation of high-resolution Earth observation microsatellites. With a successful launch, the number of satellites in this constellation will increase to 16 out of a planned 60.
Each BlackSky Gen-2 satellite has a liftoff mass of 56 kilograms and carries an identical four-channel SpaceView-24 imaging telescope, which has an aperture of 24 centimeters and a spatial resolution of one meter at an altitude of 500 kilometers. The Gen-2 satellites also carry improved solar cells for power generation and an onboard propulsion system for orbit maintenance.
“The Beat Goes On” was the eighth mission (sixth dedicated) in which a BlackSky payload has flown on Rocket Lab’s Electron, further strengthening a partnership that began with “Make It Rain” in June 2019.
During “The Beat Goes On” mission, Electron lofted its two payloads to a 450-kilometer circular orbit with an inclination of 42 degrees. This saw the rocket fly a southeasterly trajectory from the launch site after liftoff.
In addition to deploying the customer payloads, Rocket Lab tested marine recovery of Electron’s first stage. After stage separation, the booster returned to Earth under a parachute and performed a soft splashdown downrange in the Pacific Ocean, where it will be collected by a contracted customized vessel.
Once retrieved, the stage will be transported back to Rocket Lab’s production facility in Auckland, where it will be analyzed to inform future recovery and reuse missions.
The use of marine recovery for Electron marks a shift in Rocket Lab’s reuse plans, which were implemented to meet increased launch demand and reduce turnaround times between flights. Previously, the company attempted to perform mid-air retrievals of the booster using a helicopter equipped with a hook to catch and secure the falling rocket by its parachute line.
How do Rutherford engines cope with a dip in the ocean? Remarkably well.
— Rocket Lab (@RocketLab) March 20, 2023
Two attempts at mid-air catches were made in 2022 during the “There and Back Again” and “Catch Me If You Can” missions. These attempts came close to success but ultimately failed, with each booster being retrieved from the ocean after splashdown.
Thanks in part to the new focus on marine recovery, Rocket Lab has outfitted Electron with additional waterproofing alongside the silver thermal protection film and base heat shield that are prominent on boosters marked for reuse.
The company’s shift to ocean landings is not without confidence, as refurbished Rutherford engines — which are 3D printed and electric pump-fed — have undergone successful hot-fire tests after marine recovery missions. One such engine, which flew on “There And Back Again,” passed the same acceptance tests used to verify newly-built engines, including 200 seconds of firing time and multiple restarts.
Launch preparations for “The Beat Goes On” began with a successful wet dress rehearsal (WDR) test on the pad at LC-1B. During this test, Electron was loaded with propellants and mission controllers simulated a typical launch countdown to ensure that all vehicle systems were operating as expected.
Following the conclusion of the WDR, the rocket was rolled back to its hangar for payload integration and fairing encapsulation, which was completed by March 8. Electron was rolled to the pad once again a week later.
The countdown to liftoff officially commenced at T-4 hours, at which point the launch vehicle was raised to vertical. Loading of RP-1 fuel into both stages began shortly afterward, with liquid oxygen loading starting at the T-2 hour mark.
Approximately 18 minutes before launch, Rocket Lab’s launch director conducted a go/no-go poll of the launch team and verify that all systems, including those onboard Electron and its payloads, are ready for flight. The launch team is in control of the countdown up until T-2 minutes, at which point Electron’s onboard computers take over and begin the launch sequence.
The nine Rutherford engines on the first stage ignited at T-2 seconds, with liftoff occurring at T0 following a final automated status check by the flight computers.
Shortly after liftoff, Electron pitched downrange over the Pacific Ocean to align with the proper launch azimuth. At approximately one minute and 11 seconds into the flight, the vehicle passed through the region of maximum dynamic pressure — also known as max-Q — where aerodynamic stresses on the rocket are at their greatest.
Electron’s nine first stage engines continued to burn until the T+2 minute 25-second mark when they shut down in an event known as main engine cutoff (MECO). Stage separation occurred three seconds later, with the ignition of the vacuum-optimized Rutherford engine at T+2 minutes 31 seconds after launch.
The Electron rocket’s protective payload fairing was jettisoned shortly after stage separation and second-stage engine startup, exposing the BlackSky 9 and 10 satellites to space for the first time.
As the Rutherford vacuum engine continued its burn, the externally-mounted batteries that power the motor’s electric turbopumps depleted their charge, eventually becoming excess mass once fully drained. Once this happens, these empty batteries are jettisoned, and a separate battery system starts up to maintain a steady power supply to the turbopumps. This process is known as “battery hot-swapping,” and took place around six minutes into the flight.
Shortly after achieving orbit, second engine cutoff — the shutdown of the Rutherford vacuum engine — took place at approximately T+9 minutes 10 seconds. Electron’s patented kick stage with the pair of BlackSky satellites separated from the second stage approximately four seconds later.
The kick stage, equipped with a 120N Curie engine, then performed a burn starting at T+53 minutes 52 seconds after a nearly 45-minute-long coast phase. This burn will place the payloads into their final deployment orbits, with spacecraft separation taking place shortly after Curie engine cutoff.
As the second stage and payloads head on to orbit, Electron’s first stage continued to follow its trajectory after staging, eventually coasting up to apogee before falling back down through the atmosphere. The booster used a reaction control system (RCS) to orient itself to the ideal angle for re-entry.
After slowing to less than Mach 2, a drogue parachute deployed to increase drag and stabilize the first stage during descent. The main parachute deployed during the final few kilometers to further slow the stage for landing.
The vessel Seaworker, stationed downrange during the launch, will then rendezvous with the booster after splashdown and collect it for transport back to Rocket Lab’s production complex for inspection.
(Lead image: Electron launch for “The Beat Goes On” mission. Credit: Rocket Lab)