Friday, September 23, 2005

Minotaur Launch of STP-R1

A Minotaur launched the STP-R1 STP-R1 experimental satellite into space for the Air Force Research Laboratory. Payload is DARPA's Streak technology demonstration satellite. Launch occurred at dusk and caused an impressive display visible as far away as Arizona, Nevada, and Mexico.


For the U.S. Air Force's Orbital/Suborbital Program (OSP) we have developed the low-cost, four-stage Space Launch Vehicle (SLV) Minotaur rocket using a combination of U.S. government-supplied Minuteman II motors and proven Orbital space launch technologies.

The Minuteman rocket motors serve as the vehicle's first and second stages, efficiently reusing motors that have been decommissioned as a result of arms reduction treaties. Minotaur's third and fourth stages, structures and payload fairing are common with our highly reliable Pegasus XL rocket. Its capabilities have been enhanced with the addition of improved avionics systems, including our Modular Avionics Control Hardware (MACH), which is used on many of our suborbital launch vehicles.

Minotaur made its inaugural flight in January 2000, successfully delivering a number of small military and university satellites into orbit and marking the first-ever use of residual U.S. Government Minuteman boosters in a space launch vehicle. Minotaur has since extended its 100% success record with successful launches of Mightysat in July 2000, and XSS-11 in April 2005, both technology demonstration satellites for the Air Force Research Laboratory.

Minotaur • STP-R1
Launch window: 0224-0240 GMT (10:24-10:40 p.m. EDT on Sept. 22)
Launch site: SLC-8, Vandenberg Air Force Base, Calif.

What it looked like - as the exhaust was scattered by high winds ...

The Orbital/Suborbital Program Space Launch Vehicle, nicknamed Minotaur, will launch the STP-R1 experimental satellite into space for DARPA. The four-stage rocket used U.S. government-supplied Minuteman 2 motors and Pegasus rocket stages. Delayed from July. [Sept. 19]

Follow the countdown and launch of the Orbital Sciences Minotaur rocket with the U.S. military's STP-R1 "Streak" technology demonstration satellite. Reload this page for the very latest on the mission. T+plus 16 minutes. No confirmation of spacecraft deployment from the rocket has been announced. We'll be awaiting additional information from launch officials to determine if Minotaur has successfully completed its mission this evening.
0235 GMT (7:35 p.m. PDT Thurs.)

T+plus 11 minutes. Standing by for further word.
0232 GMT (7:32 p.m. PDT Thurs.)

T+plus 7 minutes, 50 seconds. Thrust has tailed off from the solid-fueled fourth stage to complete the burn.
0231 GMT (7:31 p.m. PDT Thurs.)

T+plus 7 minutes, 15 seconds. All systems appear normal as fourth stage continues to burn.
0230 GMT (7:30 p.m. PDT Thurs.)

T+plus 6 minutes, 30 seconds. Fourth stage stage ignition!
0229 GMT (7:29 p.m. PDT Thurs.)

T+plus 6 minutes, 28 seconds. The third stage has been jettisoned from the fourth stage. Coming up on ignition of the fourth stage.
0229 GMT (7:29 p.m. PDT Thurs.)

T+plus 5 minutes. Minotaur remains in the ballistic coast phase of flight. The spent third stage will be shed, followed by fourth stage ignition in approximately 90 seconds from now.
0228 GMT (7:28 p.m. PDT Thurs.)

T+plus 4 minutes. Performance so far in this launch indicates the target apogee altitude high point will be reached.
0228 GMT (7:28 p.m. PDT Thurs.)

T+plus 3 minutes, 35 seconds. The solid-fuel third stage has burned out, and the rocket is now in a brief coast period.
0227 GMT (7:27 p.m. PDT Thurs.)

T+plus 3 minutes, 15 seconds. All appears normal with the flight as the third stage solid motor continues to fire.
0227 GMT (7:27 p.m. PDT Thurs.)

T+plus 2 minutes, 45 seconds. The rocket's payload fairing nose cone has separated.
0226 GMT (7:26 p.m. PDT Thurs.)

T+plus 2 minutes, 19 seconds. Third stage ignition confirmed as the spent second stage falls way. This sheds the Minuteman 2 portion of Minotaur and the Pegasus heritage solid-fuel motors take over.
0225 GMT (7:25 p.m. PDT Thurs.)

T+plus 80 seconds. Second stage is burning well.
0225 GMT (7:25 p.m. PDT Thurs.)

T+plus 67 seconds. Staging has occurred. The first and second stages separated. And the second stage motor has ignited.
0225 GMT (7:25 p.m. PDT Thurs.)

T+plus 45 seconds. The rocket's orientation remains normal as it passes through the region of maximum aerodynamic pressures of ascent.
0224 GMT (7:24 p.m. PDT Thurs.)

T+plus 25 seconds. A good flight of Minotaur is being reported from the vehicle telemetry receiving sites.
0224 GMT (7:24 p.m. PDT Thurs.)

T+plus 10 seconds. First stage motor pressure nominal.
0224:29 GMT (7:24:29 p.m. PDT Thurs.)

LIFTOFF! Liftoff of the Minotaur rocket with the Streak satellite, launching a new Space Test Program research mission for the U.S. military.

2124 GMT (2:24 p.m. PDT)

The launch countdown has begun for this evening's liftoff of the Minotaur rocket and STP-R1 mission from California's central coast. The launch team is proceeding through the countdown checklist to ready systems and the vehicle for blastoff, which remains scheduled to occur five hours from now.

When the sun goes down at California's Vandenberg Air Force Base tonight, an obscure little satellite will blast off to begin its year-long mission for the U.S. military's research and development agency.
The Space Test Program-R1 project's Streak satellite carries a classified price tag and limited details about its underlying purpose. But the launch should be widely visible throughout central and southern California, perhaps as far inland as Arizona and Nevada, if weather conditions permit, when the Minotaur rocket roars into space to deploy its cargo.
Liftoff from the Space Launch Complex 8 pad located on Vandenberg's southern edge will occur during a window extending from 7:24 to 7:40 p.m. PDT (10:24-10:40 p.m. EDT; 0224-0240 GMT). The period opens nearly a half-hour after sunset.
Ascending skyward along a southerly trajectory over the Pacific, the slender white rocket has the potential to produce a spectacular "twilight phenomenon" display of green, blue, white and rose colors in expanding, twisting clouds. The cause: unburned fuel particles and water drops in the rocket's contrail freeze in the less dense upper atmosphere and get reflected by sunlight at high altitudes during launches timed just before sunrise or shortly after sunset.
The Orbital Sciences-managed Minotaur rocket is formed by using decommissioned first and second stages from a Minuteman 2 ICBM missile and solid-propellant motors from the commercial Pegasus rocket program for its third and fourth stages. The vehicle is designed to provide the U.S. government with reliable access to space for small satellites.
This will be the second Minotaur launch of the year and fourth since 2000. All have been successful so far.

Air Force launch officials say it will take about nine minutes for the Minotaur to haul the STP-R1 mission to the desired orbit tonight. The satellite, dubbed Streak by its operator, will test technologies for the Defense Advanced Research Projects Agency.

"Streak is a technology demonstrator whose objective is to demonstrate rapid response, short mission life, low Earth orbit space technologies and gather information about the low Earth orbit environment," a DARPA spokesperson said.

Information released by DARPA indicates Streak is fitted with two instruments -- an ion gauge and an atomic oxygen sensor.

"The vehicle will characterize the orbital regime, demonstrate operational feasibility from a command and control standpoint and also from a platform perspective for future DoD missions," the spokesperson added.

General Dynamics C4 Systems/Spectrum Astro Space Systems built the craft in Gilbert, Arizona.

DARPA is the Defense Department organization whose mission is "to maintain the technological superiority of the U.S. military and prevent technological surprise from harming our national security by sponsoring revolutionary, high-payoff research that bridges the gap between fundamental discoveries and their military use."

Tonight's weather forecast predicts an 80 percent chance of acceptable conditions for launch. Thick clouds are the only concern for violating the launch rules.

"A weak high pressure ridge moves east Thursday afternoon, while a shallow marine layer comes ashore. An upper level trough drops into the area with altocumulus and thick cirrus over Vandenberg, while low ceilings and dense fog obscure visibility," the launch weather officer reported Wednesday.

The "marine layer" of low stratus clouds will cover the entire sky over the launch pad between 400 and 1,200 feet. Mid- and high-level clouds are expected at 15,000 and 23,000 feet. Forecasters also predict fog to reduce visibility to one mile, with a temperature between 64 and 69 degrees, ground winds of 13-to-18 knots from the northwest and maximum high-altitude winds of 44 knots near 40,000 feet.

Should the launch be delayed to Friday evening for some reason, the outlook calls for a 100 percent probability of acceptable liftoff conditions. But the viewing situation at Vandenberg is likely to remain foggy.

"An upper level low and associated trough moves into the Pacific northwest. The marine layer returns, thickening and lifting as the trough moves closer and destabilizes the atmosphere. Visibility improves to 3 miles. The gradient between the exiting ridge and this trough tightens with surface winds out of the northwest at 15 - 20 knots. Upper level winds remain northwesterly."

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