Screenshot from NASA Webcast of the launch of TDRS-M. T0 got pushed to later in launch window
Mission Rundown: ULA - Atlas V 401 - TDRS-M
Written: December 16, 2022
Can’t we talk about it?
United Launch Alliance (ULA) launched a new satellite for NASA’s Tracking and Data Relay Satellite System (TDRSS) on Friday, August 18, 2017 at 08:29 EDT local time - 12:29 UTC with an Atlas V 401 carrying the TDRS-M satellite.
TDRS-M was launched inside a 40-minute window from Space Launch Complex 41 (SLC-41) at the Cape Canaveral Air Force Station in Florida.
The TDRS Payload
The Tracking and Data Relay Satellite System, or TDRSS, is a fleet of geosynchronous communications satellites that form part of NASA’s Space Network.
The current fleet of TDRS System satellites. TDRS-2 B went down with Space Shuttle Challenger
Introduced in the 1980s to support the Space Shuttle, TDRSS continues in service today, providing a relay for communications, scientific data, telemetry and commands between operators on the ground and spacecraft in Earth orbit – including the Hubble Space Telescope and the International Space Station.
The constellation consists of spacecraft stationed in 3 regions of operation: TDRS-East over the Atlantic, TDRS-West over the Pacific and TDRS-Z – covering the blind spot, or “zone of exclusion”, between the other satellites over the Indian Ocean.
With a mass of approximately 3,770 kilograms (8,310 lb), TDRS-M is slightly heavier than the previous satellites of its generation. It was originally one of two contract options in the contract signed between NASA and Boeing in December 2007 for the latter to build two spacecraft – TDRS-11 and 12.
The TDRS-M option was converted to a firm order in 2011, while the second option, TDRS-N, has not been taken up.
TDRS-M carries a communications payload that consists of S, Ku and Ka-band transponders. The satellite has a pair of steerable antennas, each capable of tracking a single spacecraft and providing communications in all three supported bands. These are used for major missions such as Hubble and the ISS.
Additional antennas allow TDRS-M to support multiple spacecraft.
The satellite is powered by a pair of solar arrays, with an R-4D-11-300 engine providing propulsion for orbit-raising and on-orbit maneuvers. TDRS-M is expected to give NASA at least fifteen years of service.
The Atlas 401 Rocket Launch
The Atlas’ Common Core Booster, or CCB, is powered by a single RD-180 engine. This burns RP-1 kerosene propellant oxidized by liquid oxygen. The RD-180 is produced by Russian manufacturer NPO Energomash, and is a two-chamber derivative of the four-chamber RD-170 series developed for the Zenit rocket.
The RD-180 ignited with about 2.7 seconds remaining until Friday’s countdown reached zero. At about 1.1 seconds after the T-0 mark, the thrust generated by the engine exceeded the vehicle’s weight and AV-074 lifted off, beginning her ascent towards orbit.
At 17.7 seconds mission elapsed time, the rocket began a series of pitch and yaw maneuvers to align itself with its planned trajectory - compass course downrange.
Flying out to the East over the Atlantic Ocean, Atlas reached Mach 1, the speed of sound, eighty seconds after liftoff. Eleven and eight-tenths of a second later the rocket experienced maximum dynamic pressure, or Max-Q.
The RD-180 powered AV-074 for the first four minutes and 2.2 seconds of the journey to orbit. At this point in the mission the engine ceased burning, an event designated booster engine cutoff, or BECO.
The spent stage was jettisoned six seconds later, with second stage ignition taking place ten seconds after stage separation. Eight seconds after second stage ignition, the payload fairing separated from around TDRS-M.
Centaur is powered by a single RL10C-1 engine. Burning liquid hydrogen and liquid oxygen, it made two burns in order to insert TDRS-M into geosynchronous transfer orbit.
The first burn, beginning after stage separation and continuing for thirteen minutes and 39.5 seconds, injected the spacecraft and upper stage into an initial parking orbit.
Following an extended 90-minute, 6-second coast, Centaur restarted for its second burn, this time firing for 56.4 seconds.
TDRS-M separated from the Centaur four minutes and 46 seconds after the end of the second burn. The orbit at spacecraft separation is expected to have a perigee – or point closest to Earth – of 4540.2 kilometers (2,883.3 miles, 2505.5 nautical miles).
Its apogee, the point farthest from Earth, will be 35,787.7 kilometers (22,237.4 mi, 19,323.8 nautical miles), while the orbit will be inclined to the equator at 26.2 degrees with an argument of perigee of 180.0 degrees.
The Atlas V 401 rocket
Friday’s launch made use of United Launch Alliance’s Atlas V rocket, which was flying in the 401 configuration.
Atlas V 401 split in its major parts. This is a generic non mission specific graphic configuration
The Atlas V, tail number AV-074, consists of a Common Core Booster (CCB) first stage, with a single-engine Centaur (SEC) upper stage and a four-meter payload fairing fitted atop the Centaur. Although the Atlas V can fly with up to five Aerojet AJ-60A solid rocket motors boosting the first stage, AV-074 will use none.
The Atlas V is an expendable medium lift launch system and member of the Atlas rocket family. The rocket is one of the most reliable in the world, having more than 70 launches with no complete failures.
The Atlas V 401 rocket, tail no. AV-074 is standing 58.2 meters - 191 feet tall on SLC-41.
The rocket has two stages. The first is a Common Core Booster (CCB), which is powered by an RD-180 engine with two bells and burns kerosene (RP-1) and liquid oxygen (LOX). This is accompanied by up to five strap-on solid rocket boosters. The second stage is the Centaur upper stage, which is powered by one or two RL10 engines and burns liquid hydrogen (LH2) and liquid oxygen (LOX).
Atlas V rocket is filled with 344 472 liter - 91 000 gallons of RP-1, liquid oxygen and liquid hydrogen. Question is now how much goes to fill each stage and the four tanks. Together they can contain 344,47 m3 RP-1, cryogenic oxygen and cryogenic hydrogen.
The Common Core Booster holds 184 728 liter - 48 800 gallon liquid oxygen chilled to below -182,96 0C Celsius or -297,33 0F Fahrenheit that can fit in a 184,73 m3 oxygen tank.
The Common Core Booster holds 94 635 liter - 25 000 gallon RP-1 highly refined kerosine at room temperature that can fit in a 94,64 m3 fuel tank.
The Centaur upper stage holds about 49 400 liter - 13 050 gallons of liquid hydrogen chilled to -252,8 0C Celsius or -423 0F Fahrenheit that can fit in a 49,40 m3 hydrogen tank.
The Centaur upper stage holds about 15 709 liter - 4 150 gallons of liquid oxygen chilled to below -182,96 0C Celsius or -297,33 0F Fahrenheit that can fit in a 15,71 m3 fuel tank.
Still to find is data on Helium gas, pressures used and number of COPV to store it. And are there tanks to store propellant used to maneuver during ascent and in orbit.
HAZ GAS operations are completed when the hydrazine is loaded. The RCS thrusters on the Centaur stage are using hydrazine as a monopropellant during orbit insertion.
The reaction control system (RCS) includes the ullage pressure thrust from the tanks and consists of twenty hydrazine monopropellant engines located around the stage in two 2-thruster pods and four 4-thruster pods. For propellant, 150 kg (340 lb) of Hydrazine is stored in a pair of bladder tanks and fed to the RCS engines with pressurized helium gas, which is also used to accomplish some main engine start up functions.
In the 401 configuration, the Atlas V is capable of carrying a structural maximum of 9,050 kg to Low Earth Orbit (LEO), and 4,950 kg to Geostationary Transfer Orbit (GTO).
The Atlas V 401 rocket has a three number configuration code.
The first number represents the fairing diameter size in 4 or 5 meters, so in this instance there is a 4 meter fairing. This launch will use the 14-meter-long (46 ft) XEPF.
The standard four-meter fairing, named the Long Payload Fairing (LPF), measures 12.2 meters (40 feet) in length and was first introduced as an optional larger fairing for the Atlas I rocket in 1990.
One or two 90-centimeter (3-foot) cylindrical segments can be added to the fairing to form an Extended Payload Fairing (EPF) or Extra-Extended Payload Fairing (XEPF) respectively for payloads that require the additional space.
The second number denotes the number of solid rocket boosters (SRBs), which attach to the base of the rocket. The number of SRBs for a 5 meter fairing can range from 0 – 5. In this case there will be no SRB’s attached to the center core.
The third number shows the number of engines on the Centaur Upper Stage, which is 1 in this configuration. So this means that this rocket will have a 4 meter fairing, no solid rocket boosters, and 1 engine bell on the Centaur Upper Stage.
Ingen kommentarer:
Send en kommentar