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32-490: Pegasus is an air-launched multistage rocket developed by Orbital Sciences Corporation (OSC) and later built and launched by Northrop Grumman . Pegasus is the world's first privately developed orbital launch vehicle. Capable of carrying small payloads of up to 443 kg (977 lb) into low Earth orbit , Pegasus first flew in 1990 and remained active as of 2021. The vehicle consists of three solid propellant stages and an optional monopropellant fourth stage. Pegasus

64-601: A scramjet -powered vehicle. The Orion stages boosted the X-43 to its ignition speed and altitude, and were discarded. After firing the scramjet and gathering flight data, the test vehicles also fell into the Pacific. The most numerous derivative of Pegasus is the booster for the Ground-based Midcourse Defense (GBMD) interceptor, basically a vertical (silo) launched Pegasus minus wing and fins, and with

96-422: A Space Shuttle algorithm. The carrier aircraft (initially a NASA B-52 , now an L-1011 owned by Northrop Grumman) serves as a booster to increase payloads at reduced cost. 12,000 m (39,000 ft) is only about 4% of a low Earth orbital altitude, and the subsonic aircraft reaches only about 3% of orbital velocity, yet by delivering the launch vehicle to this speed and altitude, the reusable aircraft replaces

128-505: A canister that encloses the lower spacecraft and mounts the upper spacecraft. The upper spacecraft deploys, the canister opens, then the lower spacecraft separates from the third-stage adapter. Since the fairing is unchanged for cost and aerodynamic reasons, each of the two payloads must be relatively compact. Other multiple-satellite launches involve "self-stacking" configurations, such as the ORBCOMM spacecraft. For their work in developing

160-534: A considerable amount of extra work to overcome. Higher densities at lower altitudes result in larger drag forces acting on the vehicle. In addition, thrust is lost due to over-expansion of the exhaust at high ambient pressure and under-expansion at low ambient pressure; a fixed nozzle geometry cannot provide optimal exhaust expansion over the full range of ambient pressure, and represents a compromise solution. Rockets launched from high altitude can be optimized for lower ambient pressure, thus achieving greater thrust over

192-400: A costly first-stage booster. In October 2016, Orbital ATK announced a partnership with Stratolaunch Systems to launch Pegasus-XL rockets from the giant Scaled Composites Stratolaunch , which could launch up to three Pegasus-XL rockets on a single flight. Pegasus components have also been the basis of other Orbital Sciences Corporation launchers. The ground-launched Taurus rocket places

224-455: A total program success rate of 89 percent. The first partial failure on 17 July 1991 caused the seven USAF microsatellites to be delivered to a lower than planned orbit, significantly reducing the mission lifetime. The last mission failure on 4 November 1996 resulted in the loss of gamma-burst identifying satellite HETE ( High Energy Transient Explorer ). The Pegasus XL, introduced in 1994 has lengthened stages to increase payload performance. In

256-518: Is expected that a larger launcher will be chosen for this dual mission launch. In August 2022 NASA announced that the 4 microsatellites of the PUNCH constellation will be launched as rideshare payloads together with SPHEREx in April 2025 on a SpaceX Falcon 9 rocket. Northrop has one Pegasus XL remaining in its inventory. It is looking for customers for those rockets. Northrop does not plan on retiring

288-435: Is no need for a launch pad or blockhouse. Air-launch-to-orbit also works well as part of a combination launch system such as a reusable air-launched single-stage-to-skyhook launch vehicle powered by a rocket or jet engine. An additional benefit of air-launch-to-orbit is a reduced delta V needed to achieve orbit. This results in a greater payload to fuel ratio which reduces the cost per kilogram to orbit. To further leverage

320-433: Is released from its carrier aircraft at approximately 12,000 m (39,000 ft) using a first stage wing and a tail to provide lift and altitude control while in the atmosphere. The first stage does not have a thrust vector control (TVC) system. Pegasus was designed by a team led by Antonio Elias. The Pegasus's three Orion solid motors were developed by Hercules Aerospace (later Alliant Techsystems ) specifically for

352-693: The Canary Islands in the Atlantic Ocean . Orbital offers launches from Alcantara , Brazil , but no known customers have performed any. Upon reaching a predetermined staging time, location, and velocity the aircraft releases the Pegasus. After five seconds of free-fall, the first stage ignites and the vehicle pitches up. The 45-degree delta wing (of carbon composite construction and double-wedge airfoil) aids pitch-up and provides some lift. The tail fins provide steering for first-stage flight, as

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384-552: The SpaceShipOne from the purpose-built White Knight carrier aircraft. The first air-launch-to-orbit was a test launch of the ASM-135 ASAT antisatellite rocket, the first commercial air-launch-to-orbit took place on 5 April 1990 with a Northrop Grumman Pegasus . The principal advantage of a rocket being launched by a high-flying airplane is that it need not fly through the lower, denser atmosphere, whose drag requires

416-459: The HAPS cuts into the fixed volume available for payload. In at least one instance , the spacecraft was built around the HAPS. Guidance is via a 32-bit computer and an IMU . A GPS receiver gives additional information. Due to the air launch and wing lift, the first-stage flight algorithm is custom-designed. The second- and third-stage trajectories are ballistic , and their guidance is derived from

448-522: The Orion 50 is discarded, and the third stage's Orion 38 motor ignites. It too has a thrust-vectoring nozzle, assisted by the nitrogen thrusters for roll. After approximately 64 seconds, the third stage burns out. A fourth stage is sometimes added for a higher altitude, finer altitude accuracy, or more complex maneuvers. The HAPS (Hydrazine Auxiliary Propulsion System) is powered by three restartable, monopropellant hydrazine thrusters. As with dual launches,

480-416: The Orion 50 motor around two axes , pitch and yaw; roll control is provided by nitrogen thrusters on the third stage. Midway through second-stage flight, the launcher has reached a near-vacuum altitude. The fairing splits and falls away, uncovering the payload and third stage. Upon burnout of the second-stage motor, the stack coasts until reaching a suitable point in its trajectory, depending on mission. Then

512-420: The Orion 50S motor does not have a thrust-vectoring nozzle. Approximately 1 minute and 17 seconds later, the Orion 50S motor burns out. The vehicle is at over 200,000 feet (61 km) in altitude and hypersonic speed . The first stage falls away, taking the wing and tail surfaces, and the second stage ignites. The Orion 50 burns for approximately 1 minute and 18 seconds. Attitude control is by thrust vectoring

544-582: The Pegasus XL rocket as of October 2019. In a Pegasus launch, the carrier aircraft takes off from a runway with support and checkout facilities. Such locations have included Kennedy Space Center / Cape Canaveral Air Force Station , Florida; Vandenberg Air Force Base and Dryden Flight Research Center , California ; Wallops Flight Facility , Virginia ; Kwajalein Range in the Pacific Ocean , and

576-562: The Pegasus XL rocket. The future (under construction as of 2019) NASA Explorer program mission Polarimeter to Unify the Corona and Heliosphere (PUNCH) was planned to be launched by Pegasus XL; but then NASA decided to merge the launches of PUNCH and another Explorer mission, Tandem Reconnection and Cusp Electrodynamics Reconnaissance Satellites (TRACERS) (also under construction as of 2019). These two space missions, consisting of 6 satellites in total, are to be launched by one launch vehicle. It

608-459: The Pegasus XL, the first and second stages are lengthened into the Orion 50SXL and Orion 50XL, respectively. Higher stages are unchanged; flight operations are similar. The wing is strengthened slightly to handle the higher weight. The standard Pegasus has been discontinued; the Pegasus XL is still active as of 2019. Pegasus has flown 44 missions in both configurations, launching 91 satellites as of October 12, 2019. Dual payloads can be launched, with

640-496: The Pegasus launcher but using advanced carbon fiber, propellant formulation and case insulation technologies originally developed for the terminated USAF Small ICBM program. The wing and fins' structures were designed by Burt Rutan and his company, Scaled Composites , which manufactured them for Orbital. Started in the spring of 1987, the development project was funded by Orbital Sciences Corporation and Hercules Aerospace, and did not receive any government funding. Government funding

672-476: The Pegasus stages and a larger fairing atop a Castor 120 first stage, derived from the first stage of the MX Peacekeeper missile. Initial launches used refurbished MX first stages. The Minotaur I , also ground-launched, is a combination of stages from Taurus launchers and Minuteman missiles, hence the name. The first two stages are from a Minuteman II ; the upper stages are Orion 50XL and 38. Due to

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704-404: The character Jean-Luc Picard was captain of a ship named Stargazer prior to the events of the series, and his first officer William Riker once served aboard a ship named Pegasus . During its 45-launch history, the Pegasus program had three mission failures (STEP-1, STEP-2 and HETI/SAC-B), and two partial failures, (USAF Microsat and STEP-2) followed by 30 consecutive successful flights for

736-750: The delta V advantage, supersonic air-launch-to-orbit has been proposed. Air-launch-to-orbit also serves as alternative if conditions do not allow launching a rocket vertically from ground to orbit due to certain reasons, such as natural disasters (earthquakes, tsunamis, floods and volcanic eruptions). According to Aviation Week and Space Technology , air-launch-to-orbit is limited by aircraft size. Additionally, airplanes may generate large lateral forces which could damage payloads. Operational: Retired: Under development: Proposed: Abandoned projects: [REDACTED] Media related to Air launch to orbit at Wikimedia Commons National Medal of Technology Too Many Requests If you report this error to

768-420: The entire operating regime. Propellant is conserved because the air-breathing carrier aircraft lifts the rocket to altitude much more efficiently. Airplane engines do not require on-board storage of an oxidizer, and they can use the surrounding air to produce thrust, such as with a turbofan . This allows the launch system to conserve a significant amount of mass that would otherwise be reserved for fuel, reducing

800-457: The first operational launch on 5 April 1990 with NASA test pilot and former astronaut Gordon Fullerton in command of the carrier aircraft. Initially, a NASA-owned B-52 Stratofortress NB-008 served as the carrier aircraft. By 1994, Orbital had transitioned to their " Stargazer " L-1011 , a converted airliner which was formerly owned by Air Canada . The name "Stargazer" is an homage to the television series Star Trek: The Next Generation :

832-468: The first stage modified by addition of a Thrust Vector Control (TVC) system. Pegasus has flown 45 missions between 1990 and 2021. 775.0 x 775.0 km @ 97.75° i 774.0 x 788.0 km @ 97.72° i Air launch to orbit Air launching has also been developed for sub-orbital spaceflight . In 2004 the Ansari X Prize $ 10 Million purse was won by a team led by Burt Rutan 's Scaled Composites , launching

864-458: The most recent Pegasus XL to be purchased — a planned June 2017 launch of NASA's Ionospheric Connection Explorer (ICON) mission — had a total cost of US$ 56.3 million, which NASA notes includes "firm-fixed launch service costs, spacecraft processing, payload integration, tracking, data and telemetry and other launch support requirements". A series of technical problems delayed this launch, which finally took place on 11 October 2019. In July 2019, it

896-521: The overall size. A larger fraction of the rocket mass can then include payload, reducing payload launch costs. Air-launch-to-orbit offers the potential for aircraft-like operations such as launch-on-demand, and is also less subject to launch-constraining weather. This allows the aircraft to fly around weather conditions as well as fly to better launch points, and to launch a payload into any orbital inclination at any time. Insurance costs are reduced as well, because launches occur well away from land, and there

928-532: The rocket, the Pegasus team led by Antonio Elias was awarded the 1991 National Medal of Technology by U.S. President George H. W. Bush. The initial launch price offered was US$ 6 million, without options or a HAPS (Hydrazine Auxiliary Propulsion System) maneuvering stage. With the enlargement to Pegasus XL and the associated improvements to the vehicle, baseline prices increased. In addition, customers usually purchase additional services, such as extra testing, design and analysis, and launch-site support. As of 2015,

960-403: The use of surplus military rocket motors, it is only used for U.S. Government and government-sponsored payloads. A third vehicle is dubbed Minotaur IV despite containing no Minuteman stages. It consists of a refurbished MX with an Orion 38 added as a fourth stage. The NASA X-43A hypersonic test vehicles were boosted by Pegasus first stages. The upper stages were replaced by exposed models of

992-585: Was announced that Northrop Grumman had lost the launch contract of the Imaging X-ray Polarimetry Explorer (IXPE) satellite to SpaceX . IXPE had been planned to be launched by a Pegasus XL rocket, and had been designed so as to fit within the Pegasus XL rocket constraints. With the IXPE launch removed from the Pegasus XL rocket, there are currently (as of 12 October 2019, after the launch of ICON) no space launch missions announced for

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1024-588: Was received to support operational testing. NASA did provide the use of the B-52 carrier aircraft on a cost-reimbursable basis during the development (captive carry tests) and the first few flights. Two Orbital internal projects, the Orbcomm communications constellation and the OrbView observation satellites, served as anchor customers to help justify the private funding. There were no Pegasus test launches prior to

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