STARDUST Launch Sequence Description
These images depict a night launch. However, the launch will actually occur during daylight hours (EST) at the Kennedy Space Center in Florida.
STARDUST on the Launch Pad
The Boeing Delta II 7426 launch vehicle consists of three stages stacked on top of each other, plus 4 small solid-fuel rockets strapped to the outside of the first stage. Each of the four solid rocket motors is 1 meter (3.28 feet) in diameter and 13 meters (42.6 feet) long; each contains 11,765 kilograms (25,937 pounds) of hydroxyl-terminated polybutadiene (HTPB) propellant and provides an average thrust of 446,023 newtons (100,270 pounds) at sea level. The casings on the solid rocket motors are made of lightweight graphite epoxy.
Closeup of Tower
At the very top of this "stack" is the spacecraft, inside a protective metal shell. Total weight of the spacecraft, including the sample return capsule and propellant carried onboard for trajectory adjustments, is 385 kilograms (848 pounds). The main bus is 1.7 meters (5.6 feet) high, 0.66 meter (2.16 feet) wide and 0.66 meter (2.16 feet) deep, about the size of an average office desk.
STARDUST Before Launch
Liftoff will take place from Space Launch Complex 17 at Cape Canaveral Air Station, Florida. Each stage has its own rocket motor. The first two stages use liquid rocket fuel. The third stage uses solid rocket fuel.
Launch of STARDUST
Launch occurs in three phases, consisting of liftoff and insertion into a 189-kilometer (102-mile) parking orbit; a coast of about a half hour until the vehicle position is properly aligned relative to the direction it must leave Earth; and final injection to an escape trajectory. The total time needed to complete the process is a little under an hour.
Burnout and Jettison of Solid Rock Motors
Sixty-six seconds after liftoff the 4 solid rocket "strap-ons" are discarded and fall into the ocean. Two of the four solid rocket strap-ons will be discarded first, and the remaining strap-on boosters will be jettisoned one second later, while the first stage continues to burn. At this point, the launch vehicle will be at an altitude of 21.9 km (13.5 miles) and traveling at a velocity of 3,862 km/hour (2,390 miles/hour).
STARDUST Prior to Main Engine Cutoff (MECO)
The central first stage continues to burn for about 3 minutes. The main body of the first stage is 2.4 meters (8 feet) in diameter and 26.1 meters (85.6 feet) long. It is powered by an RS-27A engine, which uses 96,160 kilograms (212,000 pounds) of RP-1 (rocket propellant 1, a highly refined kerosene) and liquid oxygen as its fuel and oxidizer.
After Main Engine Cutoff (MECO) First Stage Separation
4.4 minutes after liftoff the first stage shuts itself off (main engine cutoff) and is discarded (first stage separation). The spacecraft is now at an altitude of 114.5 km (71 miles) and traveling at a velocity of 20,096 km/hour (12,439 miles/hour). One stage down, two more to go!
Second Stage Ignition
13.5 seconds following main engine cutoff, the second stage is fired. The second stage is 2.4 meters (8 feet) in diameter and 6 meters (19.7 feet) long, and is powered by an AJ10-118K engine. The propellant is 5,900 kilograms (13,000 pounds) of Aerozine 50 (A-50), a mixture of hydrazine and unsymmetrical dimethyl hydrazine (UDMH), and nitrogen tetroxide as the oxidizer. This engine is restartable, and will perform two separate burns during the launch.
Jettison of Fairings
The metal shell (fairings) covering the spacecraft is discarded 6.5 seconds after second stage ignition.
STARDUST Prior to Second Stage Engine Cutoff (SECO)
The second-stage burn ends 11 minutes, 22 seconds after liftoff. At this point, the vehicle will be in a low-Earth orbit at an altitude of 189 kilometers (117 miles). Depending on the actual launch date and time, the vehicle will then coast for about 10 minutes. Once the vehicle is at the correct point in its orbit, the second stage will be restarted for a brief second burn.
Firing of Spin Motors
Before the third stage's rocket is fired to get the spacecraft out of Earth orbit and on its way, it has to be "spun up" first. Small rockets are used to make the third stage spin about its long axis. Actually, the third stage will spin on turntable attached to the second stage.
Jettison of Second Stage After the third stage "spin up", the second stage is jettisoned.
Third Stage Ignition
The third and final stage of the Delta 7426 is a Thiokol Star 37 FM booster. The The spinning third stage separates from the second stage, and the the third stage motor ignites, sending the vehicle out of earth orbit. The reason we want the vehicle to spin during this burn is so it stays pointed where we need it to point. Spinning it stabilizes it, like a spinning bullet fired from a rifle. A nutation control system (a thruster on an arm mounted on the side of the third stage) will be used to maintain stability during this 88-second burn.
Third Stage Burnout
Now, the third stage, with its solid rocket fuel exhausted, and with the spacecraft attached, are on their way in orbit around the Sun.
Jettison of Third Stage
STARDUST will then separate from the Delta's third stage. Immediately after separation from the Delta's third stage, Stardust will stop its own spinning by firing its thrusters.
About 4 minutes after separation, the spacecraft's solar array will be unfolded and be pointed toward the Sun. Shortly thereafter, the 34-meter-diameter (112-foot) antenna at the Deep Space Network complex in Canberra, Australia will acquire Stardust's signal.
Ron Baalke, STARDUST Webmaster, email@example.com
Wednesday, 26-Nov-2003 12:46:43 PST