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#40 by Ares67 on 15 Dec, 2016 19:47
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#41 by Ares67 on 15 Dec, 2016 19:56
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#42 by Ares67 on 15 Dec, 2016 19:58
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#43 by Ares67 on 15 Dec, 2016 19:59
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#44 by Ares67 on 15 Dec, 2016 20:00
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#45 by Ares67 on 15 Dec, 2016 20:02
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#46 by Ares67 on 15 Dec, 2016 20:03
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#47 by Ares67 on 15 Dec, 2016 20:05
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#48 by Ares67 on 15 Dec, 2016 20:07
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#49 by Ares67 on 15 Dec, 2016 20:08
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#50 by Ares67 on 15 Dec, 2016 20:09
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#51 by Ares67 on 15 Dec, 2016 20:13
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CHRONOLOGY OF EVENTS: August 1989 – June 1990
August 10, 1989: PEGASUS ROLLOUT AT DRYDEN
Today the official rollout of the first fully-assembled Pegasus winged satellite launcher took place at NASA’s Dryden Flight Research Center on Edwards Air Force Base, California. The vehicle in question is a “captive-inert” machine destined for flight test beneath the wing of NASA’s modified Boeing NB-52 bomber, which will serve as a mother ship for Pegasus space missions for the foreseeable future.
Verification test firings of the third stage and second stage having already been successfully concluded, the first stage verification test firing took place on July 20, and ordnance separation verification tests have also been concluded.
The first flight of Pegasus has been delayed by an escalation in the work required to fabricate a suitable adapter for attaching the spacecraft to the streamlined pylon beneath the NB-52 carrier plane’s starboard wing. Orbital Science’s Bruce Biehler explained that heat-treating and welding work on the Pegasus pylon adapter to the required tolerances proved to be a challenging task. The NB-52’s pylon has three attachment points for NASA experimental vehicles – such as the X-15 rocket plane and the HIMAT highly-maneuverable pilotless craft – that it has carried in the past.
Pegasus, however, has four attachment points. Biehler said that two new pylon adapters – one made of steel, the other fashioned from composite materials – were in the process of fabrication. It has not, as yet, been determined which of the two adapters will be used for the early test flights.
The first captive flight test will take place in mid-September. A second such captive test will take place on October 1. The new target date for the first launch of the Pegasus vehicle now lies in “late October,” according to Biehler. The machine earmarked for that flight will be identical to the captive-inert “pathfinder” machine in every respect, except that it will be loaded with live propellant. (Spaceflight News, September 1989 – edited)
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#52 by Ares67 on 15 Dec, 2016 20:14
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March 3, 1990: FLIGHT OF PEGASUS MAY BE POSTPONED
The maiden flight of Pegasus may be postponed this month because of delays in finishing safety checks. The 41,000-pound rocket is scheduled to fly under a B-52’s wing sometime between March 7 and 15. If completion cannot be made by the 15th, the flight will have to wait until April. (Countdown, May 1990)
April 2: PEGASUS ROCKET SYSTEM TO BLAST OFF WEDNESDAY
An experimental rocket system designed partly by Hercules Inc. is scheduled to blast off Wednesday, April 4. The system is called Pegasus, a three-stage rocket designed to deliver small payloads into low Earth orbit. The first mission will carry a small satellite, instruments and an experiment to release barium chemicals. Pegasus is sponsored by the Department of Defense Advanced Research Projects Agency. It was developed by Hercules Aerospace Co. and Orbital Science Corp. Hercules' Aerospace Products Group is based at Magna, and Orbital Sciences is based in Fairfax, Virginia.
Previously, the delta-winged, 50-foot missile underwent three static firings, but it never shot into the atmosphere. Like the old Bell X-15 experimental rocket plane, Pegasus is fired from beneath the wing of an aircraft. It then delivers small payloads into low Earth orbit. A B-52, traveling about 660 mph at 40,000 feet, will release the Pegasus.
1. After 5 seconds, at 39,700 feet, first-stage ignition will begin.
2. After 1 minute 21.8 seconds, at first-stage burnout, Pegasus will have soared to 199,000 feet and be traveling at more than eight times the speed of sound. The first stage, which includes a motor, the Pegasus wings and fins, will drop into the Pacific Ocean. After 1 minute 25.3 seconds, second-stage ignition will begin.
3. After 2 minutes 4 seconds, the shroud that protects the payload will fall away. The Pegasus will be at 369,000 feet.
4. After 2 minutes 40 seconds, second-stage burnout will occur. The Pegasus will coast for 5 minutes 6 seconds, its path controlled by a pressurized-nitrogen system. Third-stage ignition will occur at 248 nautical miles (about 1.5 million feet).
5. After 8 minutes 51.5 seconds, the third stage will be in orbit. A Navy communications satellite will be released while a NASA experimental satellite will remain attached to the Pegasus third stage.
Pegasus is the first all-new unmanned missile to be developed in the United States in 20 years. Hercules Aerospace built the missile body, propulsion system and components for the fins, while Orbital Science Corp. of Fairfax, Va., was responsible for engineering, vehicle integration and program management. "It's designed to capture a market that's available for small payloads," said David L. Nicponski, manager of government affairs for Hercules' Bacchus Works in Magna.
The missile is expected to launch small satellites more quickly, more easily and less expensively than existing launch vehicles. The system is considered far more flexible than ground-launched systems in use until now. Its advantages include the ability to launch into either an orbit around the poles or around the equator, using the same launch platform. It can be launched from many locations, and can overcome some adverse conditions that might prevent launching small satellites.
For example, a local storm might prevent use of a particular launch pad, but the bomber could fly beyond the storm and launch Pegasus. The new vehicle can be used "at a fraction of the cost of the ground-launched systems being used today," Nicponski said. Pegasus is part of the Bacchus Works' diversification from strictly military programs. The company considers that a stabilizing factor helping to keep jobs for the employment force of 4,600, which has an annual payroll of $150 million.
In ancient Greek mythology, Pegasus was a winged horse. Hercules gave that name to the new missile because it has wings, and the company hopes it will become "the winged workhorse" of space vehicles.
(Deseret News, April 2, 1990 / Joseph Baumann, Deseret News, April 6, 1990; The Houston Chronicle, April 6, 1990 – edited)
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#53 by Ares67 on 15 Dec, 2016 20:18
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Pegasus Takes Wing
"Today's Pegasus launch marks an important achievement for the emerging commercial launch industry. This initiative holds great promise not only for the aerospace industry but for the U.S. space program as well.”
- U.S. Vice President Dan Quayle
"We said we could do it and we did it."
- David W. Thompson, OSC President and Chief Executive Officer
A new era in spaceflight opened precisely at 12:10 p.m. PDT over the Pacific Ocean on April 5 as an orbital booster took off for the first time not from the ground, but from the air. At the moment, the Pegasus booster separated from its NASA B-52 carrier 60 miles southwest of Monterey, California, and rode a wave into the future, perhaps the precursor of many winged workhorses.
The launch, carrying a NASA experimental payload and a Navy communications satellite, marks the first time a privately designed booster lofted a payload into orbit. At first glance, the 49.2-ft.-long and 50-in.-wide Pegasus looks like a large air-to-air missile. The booster rides underneath the right wing of a NASA B-52, piloted by NASA astronaut C. Gordon Fullerton, and uses the bomber as a pseudo first stage. After the two reach an altitude of about 43,000 feet, the rocket drops from its mother ship.
After five seconds of free-flight, a stream appears gushing from the rear of the rocket, signaling the craft is alive and beginning its climb into orbit. The winged cigar needs to reach a velocity of Mach 1.2 in order to gain enough lift for its upward trek, and while doing so falls 1,200 feet below the NB-52. As the booster gains speed and begins to rise and climb back through its point of separation 19 seconds after the drop, it is traveling at Mach 1.6. The first stage burn lasts for 76 seconds, propelling the vehicle to an altitude of about 230,700 feet and a velocity of more than Mach 8.
The second stage engine takes over nine seconds after first stage burns out as the Pegasus is darting upward at a 32 degree pitch. After reaching an altitude of more than 650,000 feet, the second stage completes its 72-second burn as Pegasus coasts for nearly six minutes. The last stage successfully ignites, allowing the spacecraft to achieve a 320 nautical mile low Earth polar orbit at 12:19 p.m. PDT.
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#54 by Ares67 on 15 Dec, 2016 20:20
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#55 by Ares67 on 15 Dec, 2016 20:21
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#56 by Ares67 on 15 Dec, 2016 20:22
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PEGASUS’ PAYLOAD
The primary payload deployed by the new booster was a 422-pound multi-functional satellite coined PEGSAT, developed under a joint venture between the Defense Advanced Research Project Agency (DARPA) and NASA’s Goddard Space Flight Center. PEGSAT measured booster and satellite temperature, pressure, attitude, as well as structural vibrations and loads. The 50 inches tall and 42 inches wide PEGSAT has a price tag of 1.5 million.
During the craft’s 90-day lifespan it will also perform two barium release experiments over Canada to study the Earth’s magnetosphere and ionosphere, which will take place mid- to late-May. The experiment uses two canisters, each weighing 28.6 pounds, filled with barium mixed with a small amount of strontium. Once released in space, the metal vapors will become ionized and visible to Earth-based observers. The secondary payload is an experimental communications relay satellite for the Navy.
Also on board the launcher were instruments located in the first stage section to obtain data regarding the aerodynamic effects on the structure while traveling at hypersonic speeds. The instrumentation was funded by DARPA, a research and development organization for the Department of Defense, and was designed by NASA. The data will be used to validate the Pegasus concept, which was designed on super-computer design models, and provide data on the little-understood effects of a winged craft traveling at a velocity above Mach 8. Results from the data are expected to aid in the development of the National Aerospace Plane, which will be capable of reaching orbit while taking off and landing horizontally on a runway.
The Pegasus, a $50 million project by Orbital Sciences Corporation (OSC) and Hercules Aerospace, began only two years ago. OSC is responsible for the overall design, production and management of the Pegasus program. OSC was formed eight years ago to begin development of satellite systems such as the Transfer Orbit Stage (TOS) to launch planetary and geosynchronous spacecraft for NASA. Hercules is responsible for the engines and the payload fairings, and has one of the most scientifically advanced engine facilities in the world. Hercules also makes engines for the Peacekeeper and the Trident II, as well as the strap-on boosters used for the Delta II and the Titan IV.
Pegasus can launch a maximum payload of 900 pounds, measuring no more than 6-ft. long and 3.8-ft. wide, into a low Earth orbit. The booster weighs 41,000 pounds without payload, and is composed primarily of graphite. Only five percent of aluminum and one percent titanium are responsible for the rest of its structural weight. The 22-ft. wide clipped delta wing is made by Scale Composites, Inc. and weighs 600 pounds. The 8-in.-thick wing is able to handle more than 100,000 pounds of aerodynamic load. The maximum lift occurs at 10-15 seconds after separation at a velocity of approximately Mach 1.8.
Engineers were hoping to recover the first stage of the booster, which includes the delta wing and three 5-ft.-wide aft fins, from the Pacific Ocean for evaluation. The parts sank before a recovery ship could arrive at the scene, evidently not surviving impact.
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#57 by Ares67 on 15 Dec, 2016 20:23
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POPULAR PEGASUS
DARPA paid $6.5 million for this launch, and is scheduled to fly a second mission later this year. The Air Force Space Systems Division is slated to make a third launch in 1991, which will deploy an Independent Space Experiment System (ISES) payload. At the same time the Department of Defense and NASA are taking a serious look at Pegasus, so is Arianespace. The European company which markets the Ariane booster recently signed an agreement with Hercules for exclusive marketing rights in Europe for the Pegasus.
The Pegasus has several unique characteristics that are responsible for its popularity. The booster incorporates a relatively basic design, and uses technology and hardware from existing or previously existing programs. The NB-52 is the same that was used in the X-15 experimental aircraft program. The Pegasus attaches to the NB-52 the same as the X-15 did, with exception of a modified adapter.
The first-stage engine of the Pegasus is fixed, and two control the vehicle the three rear fins are used. The second and third-stage engines can gimbal for control; while a seal which allows the second-stage nozzle to move is the same as used in the MX missile, the third stage incorporates a smaller version of the same MX design. The rear fins and the engines are controlled by the same electronics, allowing a less complicated design.
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#58 by Ares67 on 15 Dec, 2016 20:25
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PROVING PEGASUS
The successful launch follows three tests in which the booster remained attached to the NB-52 and used inert engines. The first test flew on November 9, 1989, demonstrating the safe take-off, flight, and landing while Pegasus is attached to the NB-52. The test lasted for 90 minutes, and technicians noticed a noise in the systems and the flaking of thermal coating. Both problems were corrected and retested during the second flight made December 15, 1989.
On the second run, a simulated abort procedure was enacted, in which the Pegasus is returned to Edwards. Pilot Gordon Fullerton also, for the first time, was trying to see how high the NB-52 would fly with the Pegasus in tow. NASA has guaranteed OSC a 40,000-foot deployment capability, but Dryden officials, and the NB-52 flight crew, were hoping for 45,000 if conditions were right. “What I was able to get was about 43,000,” said Fullerton. “With the turns I had to make out there, it soaked up some performance and we never got above 43,000 on this try – but that’s entirely acceptable to the Pegasus people.”
As with the first captive flight, there proved to be no major handling surprises, other than a little Mach buffet at a little lower Mach number than Fullerton had expected. “Up at the 42, 43,000-foot range, as soon as we exceeded Mach .81, we were starting to get a little buffet somewhere – I’m not sure where. I didn’t think that would happen until beyond .84 Mach.”
It was a technical problem that arose on the second captive flight which led to the decision to make a third such flight, just to be on the safe side. There was a failure in the signaling system that shifts data from the Pegasus into the Launch Panel Operator’s station, and also transmits the data back to the control room at NASA Dryden.
“Somewhere, that failed up close to our first simulated launch, and everyone went blind as to te state of the Pegasus internally,” explained Fullerton. “If it had been a real mission, we wouldn’t have launched. That stayed broke until we were on our way back, and then it magically all started working again.”
“It was a series of signaling problems that all came at the same time,” said OSC’s Bruce Biehler, “so it’s proved difficult to pinpoint the precise fault.” Biehler revealed that DARPA had been an influential force in the decision to undertake the third captive flight, although he said a launch simulation conducted by Orbital Sciences on the ground indicated the fault was either temperature- or pressure-dependent. On January 30, 1990, Pegasus went through the final preflight test and was cleared for launch.
“There are no concerns,” Gordon Fullerton summed up the NB-52/Pegasus test flights, “either in flight or on the ground. The loads have been less than 66 percent of the limit at the worst case, which has been in one of those crashes we call a landing. We were worried about the landing loads, but a lot of that concern has gone away… They were not my best landings – they were good test landings…”
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#59 by Ares67 on 15 Dec, 2016 20:25
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