Chinese Long March 3B/E launches Bolivia's first Communications Satellite
December 20, 2013
The spacecraft was built by the China Academy of Space Technology (CAST) while the China Academy of Launch Vehicle Technology (CALT) provided the CZ-3B/E launcher contracted through the China Great Wall Industry Corporation. The satellite ground segment was delivered by China Satellite Launch & Tracking Control General (CLTC).
The satellite is named after Túpac Katari or Catari – a national hero in Bolivia who was a leader of the independence activists in the 18th century, supporting the fight of the indigenous people against colonialism of the Spanish Empire.
Onboard batteries are used to store power for night passes. The 5,200-Kilogram spacecraft is three-axis stabilized with high pointing accuracy.
TKSat-1 carries 26 Ku-Band transponders and 2 C-Band and 2 Ka-Band transponders. Four of the Ku-Band transponders and the Ka-Band transponders are used solely to cover the Bolivian Territory while the rest are used for regional coverage including the Bolivian territory and pre-determined surrounding regions. The two C-Band transponders provide continental coverage across South America. The satellite will operate at an orbital location of 87 degrees West and has a life expectancy of 15 years.
The four engines provide a total sea level thrust of 2961.6 Kilonewtons (302,000 Kilogram-force). Vehicle control during first stage flight is accomplished by individually gimbaling the four engines.
Stage separation uses the hot-staging technique. The second stage vernier engine is ignited before first stage cutoff. Moments after shutdown of the first stage, 14 Pyro Bolts are fired to severe the attachment of the first and second stage to allow the first stage to be pushed away by the exhaust of the vernier engine.
The second and third stage is common in between the Long March 3B and 3B/E versions.
Stage 2 is 9.94 meters long and shares the first stage’s diameter of 3.35 meters. It has an empty mass of 3,850 Kilograms and is loaded with 49,605 Kilograms of propellants that are consumed by a single DaFY-20-1 main engine and a four-chamber DaFY-21-1 vernier engine. The main engine provides 742 Kilonewtons of thrust (75,660 Kilogram-force) while the four chambers of the vernier engine each provide 11.8 Kilonewtons of thrust (1,200 Kilogram-force). The nozzles can be gimbaled individually to provide vehicle control during flight. The second stage main engine burns for 178 seconds, the vernier burns six seconds longer. Staging is accomplished by pyrotechnic bolts.
The Cryogenic Upper Stage of the Long March 3B/E is 12.38 meters long with a reduced diameter of 3.0 meters having an inert mass of 2,740 Kilograms. The third stage carries a total propellant load of 18,193 Kilograms of Liquid Hydrogen and Liquid Oxygen. The third stage uses Propellant Utilization Technique to adjust the propellant mixture consumed by a YF-75 cluster of two cryogenic main engines providing a total vacuum thrust of 156.9 Kilonewtons (1,600 Kilogram-force) operating at a chamber pressure of 37.6 bar. The engines are optimized for operation in vacuum conditions with an area ratio of 80:1. The third stage provides re-ignition capability to support a two-burn GTO mission profile – using the first urn to reach a parking orbit ahead of a plane-change and apogee boost as part of the second burn. The third stage is equipped with a monopropellant Propellant Management and Attitude Control System and the stage also includes the vehicle avionics. The payload fairing of the CZ-3B/E is 4.2 meters in diameter capable of hosting large payloads.
Long March countdown operations got underway approximately 7.5 hours ahead of liftoff with the activation of the launch vehicle for checkouts and reconfigurations. As the countdown got underway, teams powered up Ground Support and Launch Vehicle systems to get ready for cryogenic propellant loading on the third stage that uses Liquid Oxygen oxidizer and Liquid Hydrogen Fuel. The remaining stages were filled in the days leading up to launch as they use storable propellants.
This flight profile calls for the pitch maneuver shortly after liftoff to align the vehicle with its trajectory to the East. Booster Separation occurs 2 minutes and 21 seconds into the flight followed by first stage shutdown and separation at T+2:39. Debris of the boosters and core stage fall back to Earth and impact downrange from the launch site on China’s mainland. The fairing separates just before the 4-minute mark and also falls back to Earth for a crash landing downrange from the launch site. Around 5 minutes and 45 seconds into the mission, the second stage burns out and is jettisoned.
Shortly thereafter, the third stage ignites on its first burn which is about 4 minutes and 30 seconds in duration ending just after passing 10 minutes into the flight. After coasting in its Low Earth Parking Orbit for 10 minutes and 30 seconds, the third stage is ignited again to increase the apogee at the appropriate location which is precisely targeted. The burn begins at about T+21 minutes and is just over three minutes in duration. After shutdown, the third stage performs a re-orientation ahead of spacecraft separation at T+25 minutes and ~45 seconds.