SpaceX Falcon 9 Block 5 - KPLO Danuri - Launched August 4, 2022
Screenshot from SpaceX Webcast of the launch of KPLO
Mission Rundown: SpaceX Falcon 9 Block 5 - KPLO
Written: August 11, 2022
Fly me to the Moon - Economy class
Thursday, August 4 at 19:08 EDT, Falcon 9 launched KPLO to a ballistic lunar transfer orbit from Space Launch Complex 40 at Cape Canaveral Space Force Station, Florida.
A few seconds after liftoff, Falcon begins a pitch maneuver to put itself on the planned launch track. One minute and 12 seconds into the flight, Falcon 9 passes through Max-Q, the point of maximum dynamic pressure, which is the point where the aerodynamic stresses on the rocket will be at their peak.
After burning for about two minutes and 33 seconds, the nine first-stage engines shut down in an event designated Main Engine Cutoff (MECO). A few seconds later, the two stages separate and the second stage ignites its single Merlin Vacuum (MVac) engine.
Just under a minute into the second stage’s burn, the payload fairing separates, exposing Danuri to space for the first time.
While the second stage is performing this burn to reach orbit, the first stage continues to follow its ballistic trajectory towards Just Read The Instructions. Its four titanium grid fins deploy moments after stage separation. The stage coasts for a few minutes before three of its nine engines reignite for the entry burn. This roughly 15-20 second firing helps to protect the stage from the aerodynamic forces from reentry, also serving to slow it as it passes back into Earth’s atmosphere.
From there the first stage continues to slow down as it descends unpowered, passing back through the transonic region. With the stage at an altitude of two kilometers and a speed of roughly 235 m/s, a single engine ignites for its landing burn. This 20-30 second burn slows the stage down for a gentle landing aboard JRTI. This marked the 60th consecutive and 134th overall landing for a Falcon 9 first stage. JRTI will take the booster back to Port Canaveral to be refurbished for a future flight.
SpaceX will also recover both fairing halves in the Atlantic Ocean with the recovery vessel Bob, named after Demo-2 Astronaut Bob Behnken.
B1052-6 has a history as a Falcon Heavy side booster that has been refitted as a single launch vehicle. After 950 or so days it was decided to let it back in rotation so it wouldn’t be technically obsolete with too much dust in sensible parts of its hardware.
B1052-6 will have made its sixth flight after launching the following mission:
B1052-6 did not perform a static fire test after refurbishment and waiting for an east coast launch out of the Cape. SpaceX has since Starlink V1.0 L08 omitted this safety precaution many times so far. It is not required to perform a static fire test inhouse missions like Starlink, that was to save money and time before the launch.
SpaceX is the first entity ever that recovers and reflies its fairings. After being jettisoned, the two fairing halves will use cold gas thrusters to orientate themselves as they descend through the atmosphere. Once at a lower altitude, they will deploy drogue chutes and parafoils to help them glide down to a soft landing for recovery.
Falcon fairings halfs have been recovered and reused since 2019. Improved design changes and overall refurbishment procedures have decreased the effects of water landings and led to an increased recovery rate of fairings.
The fairings are a used pair from previous missions with no known joint mission. Both fairings survived the landing. Active fairings are equipped with four pushrods to separate the two fairing halfs.
Fairings had evenly spaced venting ports that have been redesigned a number of times by having first ten, then eight and now having their venting ports built as close pairs along the fairing edge. This prevents saltwater from the ocean from flooding and sinking the fairing, and makes refurbishment toward the next flight easier.
Stage two continued to burn for five minutes until reaching its planned low-Earth parking orbit at an altitude close to 250 km.
After reaching its parking orbit, the second stage coasted before performing its second burn, SES-2. The MVac engine reignited to conduct its trans-solar injection burn. This placed Danuri on course to use a Weak Stability Boundary/Ballistic Lunar Transfer (BLT) method to reach the Moon. L1 is a gravity tipping point between Earth and the Sun.
After another coast phase, Falcon released the spacecraft to begin its journey to the Moon. Using the BLT method, its orbit will have reached an apogee near the Earth/Moon Lagrange Point 1. As it approaches L1, the Lunar gravitational pull will help to boost the spacecraft on its way to the Moon. Danuri will use its onboard propulsion to maneuver itself into lunar orbit. The BLT transfer profile is similar to the one being used by NASA’s CAPSTONE mission, which will reach lunar orbit in November.
Once it reaches the Moon, Danuri will complete multiple burns to reach a circular orbit at an altitude of 100 kilometers (subject to a 30 km margin of error) at 90 degrees inclination - a Moon polar orbit. This is expected to be completed in December. The 100 km orbit is where Danuri’s year-long primary mission will take place.
The Payload
The 678-kilogram Danuri spacecraft is equipped with multiple monopropellant thrusters, two solar arrays, and six instruments. Five of these instruments were provided by KARI with the sixth by NASA as part of their cooperation with KARI on this project.
After three days of testing in the initial insertion orbit provided by stage 2 - Danuri will do its first Trajectory Correction Maneuver - TCM-1 burn on August 7 at 01:00:48 UTC, which will inject it into deep space for a 55 day long journey to the halfway point where the second Lunar insertion burn - if needed - will break it ever so slightly, that Danuri will ‘fall’ back towards the Moon instead of the Earth.
Roughly four months after launch, the KLPO satellite will reach a 100 km circular polar low-lunar orbit via the ballistic lunar capture method. To reach lunar orbit, the spacecraft has four main 30 N thrusters and four 5 N thrusters for attitude control. To remain in contact with the Earth, KLPO has S-band and X-band transponders that are powered by a 760-watt set of solar panels.
The Danuri satellite has six instruments or ‘payloads’ onboard:
Lunar Terrain Imager (LUTI). This instrument will be used to image the lunar surface and scout for future landing sites. The instrument has a ~5-meter resolution.
Wide-Angle Polarimetric Camera (PolCam). Polarimetry is used to analyze the composition of regolith from a distance. The PolCam will be used to investigate the entirety of the lunar regolith, with the exception of that on the poles.
KPLO Magnetometer (KMAG). This instrument will be used to measure the strength of the lunar poles' magnetic fields.
KPLO Gamma Ray Spectrometer (KGRS). Using spectroscopy–the process of looking at emission gaps–this instrument will research the composition of the lunar regolith.
Delay-Tolerant Networking experiment (DTNPL) - Sending KPOP music videos to and from Danuri and internet receivers of said videos to demonstrate lag in signals.
NASA ShadowCam. NASA’s ShadowCam will search the lunar surface for evidence of large ice deposits.
Danuri will join NASA’s Lunar Reconnaissance Orbiter (LRO) and CAPSTONE missions in lunar orbit. Together these spacecraft will contribute data to support the Artemis program. South Korea signed the Artemis Accords in 2021 becoming the tenth nation to do so.
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