Launched on Friday, November 4th, 2022, “Catch me if you can” marked the 9th launch attempt of the year for the Californian Based Company and the 32nd flight for an Electron Launcher.
The rocket successfully placed the MATS satellite, made by OHB for the Swedish National Space Agency, on a circular orbit at 585km of altitude. However, the mid-air recovery attempt was unsuccessful, with the first stage booster splashing down in the ocean.
Mission Recap – Credits: Rocket Lab via Flickr
Initially planned to be launched onboard a Russian vehicle, the MATS satellite aims at studying atmospheric waves from 50 to 100 km above sea level; this is achieved by imaging variation in the light emitted by oxygen molecules, as well as structures in the highest clouds in our atmosphere, the so-called noctilucent clouds, which form at around 80 km.
These waves are variations of the atmosphere density and can originate when, for example, winds pass over mountains or other terrains. Studying this phenomenon will allow scientists to understand the mesosphere’s behavior better.
As per standard procedure by Rocket Lab, propellant loading began several hours before liftoff, followed by a go-nogo poll at T-18 minutes. At T-10 mins, the launch entered its terminal phase, with the launcher taking control of the countdown at T-2 mins.
Liftoff occurred at 17:27 GMT from Pad B at Launch Complex 1 on New Zealand’s Mahia Peninsula; after 2 minutes and 29 seconds there was MECO (Main Engine Cut Off), and shortly after the first stage separated from the rest of the vehicle beginning its way back to Earth.
Approximately 7 minutes after separation, the second stage concluded its mission and passed the role of final orbit insertion to the Kick Stage, which, after a short coast phase and one final burn, deployed the payload.
Let’s now go back to the first stage; soon after separation, the booster reached its apogee and began the descent. The plan was to catch it mid-air via helicopter; however, ground controllers lost telemetry while passing through the upper layers of the atmosphere. Due to safety reasons, the attempt was canceled. In the end, the booster landed in the ocean and was quickly recovered by Rocket Lab Vessel to be brought back to shore for analysis and possibly reuse.
After a great launch, we can confirm the primary mission is on track! Unfortunately no helicopter catch attempt today due to telemetry loss from Electron’s 1st stage during re-entry. As standard procedure, we pull the helicopter from the recovery zone if this happens pic.twitter.com/0tTnlh33Al— Rocket Lab (@RocketLab) November 4, 2022
Recovering a falling booster
As of today, Electron is the only rocket booster (potentially) capable of recovery and reuse alongside SpaceX Falcon 9, but all the similarities end here. Falcon 9 uses a propulsive reentry procedure: the booster lights its engines at least twice after separation.
Instead, Electron follows a different method: shortly after liftoff, a modified Sikorsky S-92 large helicopter enters the capture zone – approximately 160 nautical miles from New Zealand’s shore. Meanwhile, the booster is experiencing the most stressful phase of the mission – Rocket Lab calls it “The Wall“; the vehicle travels at 2350 m/s with an external temperature of 2400 °C.
As soon as it goes below Mach 2, a drogue chute deploys for further deceleration and stabilization. After that, the main chute is deployed, and the recovery via helicopter takes place.
Granting the survivability of a booster without controlling its speed it’s a complicated task; for this reason, several updates were introduced in the past years, starting from a more robust and precise RCS (Reaction Control System) to achieve optimal attitude; moreover, an improved heat shield was mounted at the base of the rocket which, in conjunction whit special coating, aims at protecting the vehicle from extreme thermal loads.
As of today, no booster mid-air-retrieval has been completed during commercial missions, although several successful attempts were made during the test phases. It’s’ still undefined when Rocket Lab could try the procedure again, with two or three launches still planned for 2022.