Northrop Grumman Pegasus Explained

Northrop Grumman Pegasus should not be confused with Pegasus (satellite).

Pegasus
Function:Small-lift launch vehicle
Manufacturer:Northrop Grumman
Country-Origin:United States
Cpl:[1]
Capacities:
Inclination:28.5°
Height:
XL:
Mass:
XL:
Stages:3
Status:Active
Launches:45
Success:40
Fail:3
Partial:2
First:5 April 1990 (Pegsat / NavySat)
Last:13 June 2021 (TacRL-2 / Odyssey)
Derivatives:Minotaur-C
Comparable:Electron, Vector-H, Falcon 1, LauncherOne
Stagedata:
Type:stage
Stageno:First
Burntime:75.3 seconds
Stageno:First
Type:stage
Diff:Pegasus XL
Burntime:68.6 seconds
Type:stage
Stageno:Second
Burntime:75.6 seconds
Stageno:Second
Type:stage
Diff:Pegasus XL
Burntime:71 seconds
Type:stage
Stageno:Third
Burntime:66.8 seconds
Type:stage
Diff:optional
Stageno:Fourth
Burntime:131 + 110 seconds (2 burns)

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.[2] [3] Capable of carrying small payloads of up to into low Earth orbit, Pegasus first flew in 1990 and remained active . The vehicle consists of three solid propellant stages and an optional monopropellant fourth stage. Pegasus is released from its carrier aircraft at approximately 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.[4]

History

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 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 was received to support operational testing.[5] 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.[6]

There were no Pegasus test launches prior to 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 : 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.[7]

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 a total program success rate of 89 percent.[8] 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).[9]

The Pegasus XL, introduced in 1994 has lengthened stages to increase payload performance.[10] In 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.[11] [12]

Dual payloads can be launched, with 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 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, 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".[13] A series of technical problems delayed this launch, which finally took place on 11 October 2019.

In July 2019, it 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 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 is expected that a larger launcher will be chosen for this dual mission launch.[14] 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.[15] [16] SpaceX's internal launch cost for a reusable Falcon 9 rocket is less than $20 million,[17] while having vastly larger payload capacity, so it seems likely that SpaceX would be able to profitably underbid the Pegasus XL for most satellite launches.

Northrop has one Pegasus XL remaining in its inventory. It is looking for customers for those rockets. Northrop does not plan on retiring the Pegasus XL rocket as of October 2019.[18]

Launch profile

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 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 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 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 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, 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 a Space Shuttle algorithm.

Carrier aircraft

See main article: Stargazer (aircraft).

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. 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 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.[19]

Related projects

Pegasus components have also been the basis of other Orbital Sciences Corporation launchers.[20] The ground-launched Taurus rocket places 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 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 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 the first stage modified by addition of a Thrust Vector Control (TVC) system.

Launch statistics

Carrier airplane

Launch history

Pegasus has flown 45 missions between 1990 and 2021.[11]

Flight No.Date / time (UTC)Rocket,
Configuration
Launch sitePayloadPayload massTarget Orbit[21] Actual OrbitCustomerLaunch
outcome
15 April 1990
19:10:17
Standard (B-52)Edwards AFBPegsat, NavySat320.0 x 360.0 km @ 94.00° i273.0 x 370.0 km @ 94.15° i
217 July 1991
17:33:53
Standard w/ HAPS (B-52)Edwards AFBMicrosats (7 satellites)389.0 x 389.0 km @ 82.00° i192.4 x 245.5 km @ 82.04° i
Orbit too low, spacecraft reentered after 6 months instead of planned 3-years lifetime.
39 February 1993
14:30:34
Standard (B-52)Kennedy Space CenterSCD-1405.0 x 405.0 km @ 25.00° i393.0 x 427.0 km @ 24.97° i
In the final minute of the launch sequence an abort was called by NASA's Range Safety Officer (RSO). Despite the abort call, the launch was reinitiated by then operator Orbital Sciences Corporation's test conductor without coordination with other launch participants.[22] [23] Launch was completed without further issue. In an investigation led by the National Transportation Safety Board (NTSB) found that: fatigue; lack of clear command, control, and communication roles were factors that led to the incident.
425 April 1993
13:56:00
Standard (B-52)Edwards AFBALEXIS – Array of Low Energy X-ray Imaging Sensors400.0 x 400.0 km @ 70.00° i404.0 x 450.5 km @ 69.92° i
519 May 1994
17:03
Standard w/ HAPS (B-52)Edwards AFBSTEP-2 (Space Test Experiments Platform/Mission 2/SIDEX)450.0 x 450.0 km @ 82.00° i325.0 x 443.0 km @ 81.95° i
Orbit slightly low
627 June 1994
21:15
XL (L-1011)Vandenberg AFBSTEP-1 (Space Test Experiments Platform/Mission 1)--
Loss of vehicle control 35 seconds into flight, flight terminated.
73 August 1994
14:38
Standard (B-52)Edwards AFBAPEX195.0 x >1000 km @ 70.02° i195.5 x 1372.0 km @ 69.97° i
83 April 1995
13:48
Hybrid (L-1011)Vandenberg AFBOrbcomm (2 satellites), OrbView 1398.0 x 404.0 km @ 70.00° i395.0 x 411.0 km @ 70.03° i
922 June 1995
19:58
XL (L-1011)Vandenberg AFBSTEP-3 (Space Test Experiments Platform/Mission 3)--
Destroyed during second-stage flight
109 March 1996
01:33
XL (L-1011)Vandenberg AFBREX II450.0 x 443.0 km @ 90.00° i450.9 x 434.3 km @ 89.96° i
1117 May 1996
02:44
Hybrid (L-1011)Vandenberg AFBMSTI-3298.0 x 394.0 km @ 97.13° i293.0 x 363.0 km @ 97.09° i
122 July 1996
07:48
XL (L-1011)Vandenberg AFBTOMS-EP340.0 x 955.0 km @ 97.40° i341.2 x 942.9 km @ 97.37° i
1321 August 1996
09:47:26
XL (L-1011)Vandenberg AFBFAST (Fast Auroral Snapshot Explorer)350.0 x 4200.0 km @ 83.00° i350.4 x 4169.6 km @ 82.98° i
144 November 1996
17:08:56
XL (L-1011)Wallops Flight FacilityHETE, SAC-B510.0 x 550.0 km @ 38.00° i488.1 x 555.4 km @ 37.98° i
Satellites not ejected from third stage
1521 April 1997
11:59:06
XL (L-1011)Gando Air Base, Gran Canaria, SpainMinisat 01, Celestis space burial587.0 x 587.0 km @ 151.01° i562.6 x 581.7 km @ 150.97° i
16August 1, 1997
20:20:00
XL (L-1011)Vandenberg AFBOrbView-2310.0 x 400.0 km @ 98.21° i300.0 x 302.0 km @ 98.28° i
On the line with partial success
17August 29, 1997
15:02:00
XL (L-1011)Vandenberg AFBFORTE800.0 x 800.0 km @ 70.00° i799.9 x 833.4 km @ 69.97° i
18October 22, 1997
13:13:00
XL (L-1011)Wallops Flight FacilitySTEP-4 (Space Test Experiments Platform/Mission 4)430.0 x 510.0 km @ 45.00° i430.0 x 511.0 km @ 44.98° i
19December 23, 1997
19:11:00
XL w/ HAPS (L-1011)Wallops Flight FacilityOrbcomm (8 satellites)825.0 x 825.0 km @ 45.00° i822.0 x 824.0 km @ 45.02° i
20February 26, 1998
07:07:00
XL (L-1011)Vandenberg AFBSNOE, BATSAT580.0 x 580.0 km @ 97.75° i582.0 x 542.0 km @ 97.76° i
21April 2, 1998
02:42:00
XL (L-1011)Vandenberg AFBTRACE600.0 x 650.0 km @ 97.88° i599.9 x 649.2 km @ 97.81° i
22August 2, 1998
16:24:00
XL w/ HAPS (L-1011)Wallops Flight FacilityOrbcomm (8 satellites)818.5 x 818.5 km @ 45.02° i819.5 x 826.0 km @ 45.01° i
23September 23, 1998
05:06:00
XL w/ HAPS (L-1011)Wallops Flight FacilityOrbcomm (8 satellites)818.5 x 818.5 km @ 45.02° i811.0 x 826.0 km @ 45.02° i
24October 22, 1998
00:02:00
Hybrid (L-1011)Cape CanaveralSCD-2750.0 x 750.0 km @ 25.00° i750.4 x 767.0 km @ 24.91° i
25December 6, 1998
00:57:00
XL (L-1011)Vandenberg AFBSWAS635.0 x 700.0 km @ 70.00 ° i637.7 x 663.4 km @ 69.91° i
26March 5, 1999
02:56:00
XL (L-1011)Vandenberg AFB540.0 x 540.0 km @ 97.56° i539.0 x 598.0 km @ 97.53° i
27May 18, 1999
05:09:00
XL w/ HAPS (L-1011)Vandenberg AFBTerriers, MUBLCOM550.0 x 550.0 km @ 97.75° i,

775.0 x 775.0 km @ 97.75° i

551.0 x 557.0 km @ 97.72° i,

774.0 x 788.0 km @ 97.72° i

28December 4, 1999
18:53:00
XL w/ HAPS (L-1011)Wallops Flight FacilityOrbcomm (7 satellites)825.0 x 825.0 km @ 45.02° i826.5 x 829.0 km @ 45.02° i
29June 7, 2000
13:19:00
XL (L-1011)Vandenberg AFBTSX-5 (Tri-Service-Experiments mission 5)405.0 x 1.750.0 km @ 69.00° i409.9 x 1,711.7 km @ 68.95° i
30October 9, 2000
05:38:00
Hybrid (L-1011)Kwajalein AtollHETE 2600.0 x 650.0 km @ 2.00° i591.9 x 651.9 km @ 1.95° i
31February 5, 2002
20:58:00
XL (L-1011)Cape CanaveralRHESSI600.0 x 600.0 km @ 38.00° i586.4 x 602.0 km @ 38.02° i
32January 25, 2003
20:13:00
XL (L-1011)Cape CanaveralSORCE645.0 x 645.0 km @ 40.00° i622.3 x 647.3 km @ 39.999° i
33April 28, 2003
11:59:00
XL (L-1011)Cape CanaveralGALEX – Galaxy Evolution Explorer690.0 x 690.0 km @ 29.00° i689.8 x 711.3 km @ 28.99° i
34June 26, 2003
18:53:00
XL (L-1011)Vandenberg AFBOrbView-3369.0 x 470.0 km @ 97.29° i367.1 x 440.5 km @ 97.27° i
35August 13, 2003
02:09:00
XL (L-1011)Vandenberg AFBSCISAT-1650.0 x 650.0 km @ 73.92° i647.9 x 659.7 km @ 73.95° i
36April 15, 2005
17:26:00
XL w/ HAPS (L-1011)Vandenberg AFBDART538.7 x 566.7 km @ 97.73° i541.2 x 548.8 km @ 97.73° i
37March 22, 2006
14:03:00
XL (L-1011)Vandenberg AFBST-5 – Space Technology 5 (3 satellites)300.0 x 4500.0 km @ 105.6° i301.1 x 4571.0 km @ 105.62° i
38April 25, 2007
20:26:00
XL (L-1011)Vandenberg AFBAIM – Aeronomy of Ice in the Mesosphere[24] 600.0 x600.0 km @ 97.77° i601.3 x 596.2 km @ 97.79° iNASA
39April 16, 2008
17:02:00
XL (L-1011)Kwajalein AtollC/NOFS[25] 400.0 x 850.0 km @ 13.0° i401.0 x 868.0 km @ 12.99° iSTP / AFRL / DMSG
40October 19, 2008
17:47:23
XL (L-1011)Kwajalein AtollIBEX – Interstellar Boundary Explorer[26] 207.0 x 412.0 km @11.0° i206.4 x 445.0 km @ 10.99° iNASA
41June 13, 2012
16:00:00
XL (L-1011)Kwajalein Atoll[27] ≥530.0 x ≤660.0 km @ 5.0 – 7.0° i621.2 x 638.5 km @ 6.024° iNASA / JPL[28]
42June 28, 2013
02:27:46[29]
XL (L-1011)Vandenberg AFBIRIS – Interface Region Imaging Spectrograph SMEX≥620.0 x ≤670.0 km @97.89° i622.9 x 669.3 km @ 97.894° iNASA[30]
43December 15, 2016
13:37:00
XL (L-1011)Cape CanaveralCyclone Global Navigation Satellite System (CYGNSS)[31] [32] 510.0 x 6888.0 km @ 35° i511.5 x 6908.1 km @ 34.97° iNASA[33]
4411 October 2019
01:59:05
XL (L-1011)Cape CanaveralIonospheric Connection Explorer (ICON)[34] [35] LEO, 590 x 607 km 608.4 x 571.6 @ 26.98° iUC Berkeley SSL / NASA[36]
4513 June 2021
08:11[37] [38]
XL (L-1011)Vandenberg Space Force BaseTacRL-2 (Odyssey)LEO
-
U.S. Space Force[39]

Launch failures

Partial successes

See also

External links

Notes and References

  1. Web site: Surplus Missile Motors: Sale Price Drives Potential Effects on DOD and Commercial Launch Providers . 2024-07-07 . . en.
  2. Web site: Pegasus Rocket . Northrop Grumman . 28 July 2020.
  3. Web site: Pegasus rocket . Oxford Reference . 3 March 2023.
  4. Web site: Pegasus User's Guide. Orbital-ATK. October 2015. https://web.archive.org/web/20160113130631/https://www.orbitalatk.com/flight-systems/space-launch-vehicles/pegasus/docs/Pegasus_UsersGuide.pdf. 13 January 2016.
  5. Pegasus First Mission Flight results. Mosier. Marty. Harris. Gary. Richards. Bob. Rovner. Dan. Carroll. Brent . 1990. Proceedings of the 4th AIAA/USU Conference on Small Satellites. 1. 1990aiaa....1.....M.
  6. Web site: Rebecca Hackler . NASA Johnson Space Center Oral History Project Commercial Crew & Cargo Program Office Edited Oral History Transcript. NASA. 3 June 2013.
  7. Web site: startrek.com. startrek.com.
  8. https://www.flightglobal.com/news/articles/nasa-reviews-space-access-after-second-pegasus-failure-21724/ NASA reviews space access after second Pegasus failure
  9. https://www.newscientist.com/article/mg15220560-900-pegasus-clings-to-its-satellite-cargo/ Pegasus clings to its satellite cargo
  10. News: The Launch Pad Lesson: With Rockets Come Risks. John Mintz. October 11, 1995. May 12, 2023. Washington Post.
  11. Web site: Pegasus Mission History. Northrop Grumman. 2 November 2018. 11 October 2019. https://web.archive.org/web/20191011024914/https://www.northropgrumman.com/Capabilities/Pegasus/Documents/Pegasus_Mission_History.pdf. dead.
  12. Web site: Pegasus Rocket. 13 October 2019. 13 October 2019. https://web.archive.org/web/20191013233200/https://www.northropgrumman.com/Capabilities/Pegasus/Pages/Pegasus-Missions.aspx. dead.
  13. Web site: NASA Awards Launch Services Contract for Ionospheric Connection Explorer. 26 September 2017. NASA.
  14. News: SpaceX wins NASA contract to launch X-ray telescope on reused rocket. Clark. Stephen. Spaceflight Now. 8 July 2019. 10 July 2019.
  15. Web site: Interrante . Abbey . PUNCH Announces Rideshare with SPHEREx and New Launch Date . 3 August 2022 . 3 August 2022 . NASA.
  16. News: Potter. Sean. NASA Awards Launch Services Contract for SPHEREx Astrophysics Mission. 4 February 2021. NASA. 4 February 2021.
  17. Web site: Some European launch officials still have their heads stuck in the sand. Ars Technica. Eric Berger.
  18. Web site: Rockets purchased by Stratolaunch back under Northrop Grumman control – Spaceflight Now.
  19. Web site: Foust. Jeff. Stratolaunch to launch Pegasus rockets. SpaceNews. June 7, 2018. October 6, 2016.
  20. Web site: Barron Beneski. Letter: "Qualified Success" Sells Pegasus Short. SpaceNews. 6 December 2011.
  21. Web site: September 2020. Pegasus Payload User's Guide. Northrop Grumman. 111–113.
  22. Web site: 5 March 1993 . Pegasus/SCD 1 Launch Anomaly Review Committee Final Report of March 1993 . 2023-08-05 . llis.nasa.gov . Goddard Space Flight Center.
  23. Web site: NTSB . 26 July 1993 . Special Investigation Report - Commercial Space Launch Incident Launch Procedure Anomaly Orbital Sciences Corporation Pegasus/SCD-1 80 Nautical Miles East of Cape Canaveral, Florida February 9, 1993 . 5 August 2023.
  24. Web site: ESA . AIM (Aeronomy of Ice in the Mesosphere) . 31 March 2020 . 5 August 2020 . https://web.archive.org/web/20200805170230/https://directory.eoportal.org/web/eoportal/satellite-missions/content/-/article/aim . dead .
  25. Web site: ESA . C/NOFS (Communication/Navigation Outage Forecast System) . 31 March 2020.
  26. Web site: IBEX - eoPortal Directory - Satellite Missions. directory.eoportal.org. en-US. 2020-03-31.
  27. Web site: Nuclear Spectroscopic Telescope Array, or NuSTAR . . June 2012 . 16 June 2012.
  28. Web site: NuSTA. December 2010. dead. https://web.archive.org/web/20110717133200/http://www.nustar.caltech.edu/uploads/updates/NuSTAR_2010dec_update.pdf. 2011-07-17.
  29. Web site: NASA's Consolidated Launch Schedule. NASA. 2013-05-14.
  30. Web site: IRIS Launch Coverage . NASA . June 27, 2013 . 28 June 2013 . 28 June 2013 . https://web.archive.org/web/20130628203610/http://www.nasa.gov/mission_pages/iris/launch/launch_blog.html . dead .
  31. Web site: NASA Awards Launch for Orbital's Pegasus Rocket . Orbital press release . April 1, 2014 . 6 April 2015 . 27 December 2016 . https://web.archive.org/web/20161227201948/http://www.parabolicarc.com/2014/04/02/nasa-awards-launch-orbitals-pegasus-rocket/ . dead .
  32. Web site: Pegasus launches CYGNSS constellation following Stargazer release. 2016-12-15. NASASpaceFlight.com. en-US. 2020-03-29.
  33. Web site: Graham. William. Pegasus launches CYGNSS constellation following Stargazer release. NASASpaceFlight. 16 December 2016. 15 December 2016.
  34. Web site: Launch of NASA ionospheric probe delayed to examine rocket issue. Spaceflight Now. Clark. Stephen. 10 November 2017. 2020-03-29.
  35. Web site: ICON Fast acts . icon.ssl.berkeley.edu. 2020-03-29.
  36. Web site: Gebhardt. Chris. NASA's ICON mission launches on Northrop Grumman Pegasus XL rocket. NASASpaceFlight.com. 11 October 2019. 11 October 2019.
  37. Web site: Erwin. Sandra. U.S. Space Force to launch "space domain awareness" satellite on Pegasus rocket. SpaceNews. 10 June 2021. 10 June 2021.
  38. Web site: Clark. Stephen . Northrop Grumman's Pegasus rocket selected for responsive launch demo. Spaceflight Now. 17 March 2021. 29 April 2021.
  39. Web site: Tingley . Brett . 2021-06-14 . Space Force Got A Satellite Into Orbit In Just Four Months . live . https://web.archive.org/web/20220703214755/https://www.thedrive.com/the-war-zone/41076/the-space-force-designed-and-launched-a-satellite-into-orbit-in-just-four-weeks . 2022-07-03 . 2022-10-26 . The Drive . en.
  40. Book: Isakowitz, Steven J. . International reference guide to space launch systems . American Institute of Aeronautics and Astronautics . 1-56347-591-X . 4 . Reston, VA . 2004 . 290 . registration.