WorldView-4

WorldView-4 (WV 4), previously known as GeoEye-2, is a third generation commercial Earth observation satellite launched on 11 November 2016. The spacecraft is operated by DigitalGlobe. With a maximum resolution of 31 cm (12 in), WorldView-4 provides similar imagery as WorldView-3, the highest resolution commercially available at the time of its launch.[10]

WorldView-4
NamesGeoEye-2
Mission typeEarth observation
OperatorDigitalGlobe
COSPAR ID2016-067A
SATCAT no.41848
Websitehttp://worldview4.digitalglobe.com
Mission durationPlanned: 7+ years
Final: 2 years, 1 month, 26 days
Spacecraft properties
BusLM-900[1]
ManufacturerLockheed Martin Space Systems[1]
Launch mass2,485 kg (5,479 lb)[2]
Dimensions7.9 × 5.3 m (26 × 17 ft)[3]
Start of mission
Launch date11 November 2016, 18:30:33 (2016-11-11UTC18:30:33) UTC[4]
RocketAtlas V 401, AV-062[5]
Launch siteVandenberg SLC-3E[5]
ContractorUnited Launch Alliance
Entered service26 November 2016[6]
End of mission
DisposalDeclared unrecoverable
Declared7 January 2019 (2019-01-08)
Orbital parameters
Reference systemGeocentric
RegimeSun-synchronous[3]
Semi-major axis6,989.75 km (4,343.23 mi)
Eccentricity0.000238
Perigee altitude609.95 km (379.01 mi)
Apogee altitude613.28 km (381.07 mi)
Inclination97.98 degrees
Period96.93 minutes
Mean motion14.86 rev/day
Repeat interval3 days[7]
Velocity7.55 km/s (4.69 mi/s)
Epoch14 November 2016, 09:00:47 UTC[8]
Main telescope
NameGeoEye Imaging System-2
Diameter1.1 m (3.6 ft)[9]
WavelengthsPanchromatic: 450-800 nm[3]
Multispectral: 450-920 nm[3]
ResolutionPanchromatic: 31 cm (12 in)[3]
Multispectral: 124 cm (49 in)[3]
DigitalGlobe fleet
 

The spacecraft suffered a failure in one of its control moment gyroscopes in January 2019, and operations were unable to be recovered.[11]

History

Work on GeoEye-2 began in October 2007 when commercial imagery company GeoEye selected ITT Corporation to begin work on long lead-time items for the satellite camera system.[12][13] In March 2010, an initial contract for construction of the spacecraft was awarded to Lockheed Martin Space Systems, which previously built the Ikonos imaging satellite.[14] At the time, GeoEye-2 was planned for launch in late 2012.[15] The spacecraft's preliminary design review was completed in November 2010, while its critical design review was completed in June 2011.[16][17]

Lockheed Martin issued a contract to ITT Corporation in August 2010 to continue work on the camera system,[13] and the company announced the completion of the system's critical design review on 1 March 2011.[18] The system was delivered to Lockheed Martin in April 2012,[19] and was mated to the spacecraft bus the following month.[20]

DigitalGlobe agreed to purchase GeoEye in July 2012,[21] and finalized the merger in January 2013.[22] At the time, each company had a satellite being prepared for launch: WorldView-3 and GeoEye-2. Because WorldView-3 offered multiple short-wavelength infrared channels in addition to the standard panchromatic and multiwavelength channels, the company chose to proceed with its launch and to place GeoEye-2 into storage.[23]

In July 2014, DigitalGlobe announced that GeoEye-2 had been renamed to WorldView-4 to better match the company's branding, and that, due to a projected increase in product demand, the spacecraft's launch had been scheduled for mid-2016.[24][25] The total cost of the spacecraft, including insurance and launch, is estimated at US$835 million.[26]

The first public image from WorldView-4 was taken on 26 November 2016 and released on 2 December.[6]

In January 2019, WorldView-4 was announced to have suffered a failure in one of its control moment gyroscopes, and is considered no longer usable.[11] WorldView-4 was insured against satellite failure, and in spring 2019 the company owning the satellite, Maxar, which had acquired DigitalGlobe in 2017, announced that they had received the full US$183 million insurance payment.[27]

Launch
WorldView-4 launches aboard an Atlas V rocket

WorldView-4 was launched on 11 November 2016 at 18:30:33 UTC from Vandenberg Air Force Base Space Launch Complex 3E aboard an Atlas V rocket.[4][28] The rocket launched in the 401 configuration with serial number AV-062, and was provided and administered by United Launch Alliance.[5] This is the same rocket that had been scheduled to launch the InSight Mars lander, which was delayed until 2018.[29] The rocket had been erected at the Vandenberg launch pad on 16 December 2015 for the InSight mission; after the WorldView-4 mission took the place of InSight, the rocket was allowed to remain vertical at the pad protected by its mobile service tower.[2] The WorldView-4 payload was fixed atop the rocket during the second week of September 2016.[2]

Originally scheduled for launch on 29 June 2016, the flight was rescheduled to 15 September and then to 16 September.[5] During countdown on 16 September, the launch was scrubbed due to a liquid hydrogen leak in the ground support equipment resulting in an ice ball forming on an umbilical cable. The launch was rescheduled for 18 September to allow for the replacement of a fill-and-drain valve, determined to be the cause of the leak.[30]

The Canyon Fire, a wildfire that burned over 5,157 hectares (12,742 acres) on the southern section of Vandenberg,[31] resulted in a further launch delay so that the base could "concentrate [their] resources on the situation at hand."[32] As a result of scheduling availability on the Western Range, the flight was rescheduled for 26 September.[32] Continued efforts in fighting the Canyon Fire caused an indeterminate delay of the launch to no earlier than October 2016.[33] Four additional fires of varying sizes broke out between 22 and 27 September; while all were contained by the end of the 27th, base commander John Moss stated that until all facilities and instrumentation could be surveyed, no preliminary launch date could be determined.[34][35]

Repairs were made to the base's infrastructure affected by the wildfire, including power and communications, and the launch date was reset to 6 November.[36] The date was later pushed back to 11 November as ULA worked to fix "minor Atlas V booster issues" found during preparations.[37]

Instrument

The spacecraft's telescope is called the GeoEye Imaging System-2,[38] also known as SpaceView 110,[39] which was designed and built by ITT Corporation (later ITT Exelis and Harris).[19] The telescope mirror is 1.1 m (3.6 ft) in diameter.[9] It provides panchromatic images at a highest resolution of 31 centimeters per pixel (12 in/px) between 450 and 800 nanometers, and multispectral images at 124 centimeters per pixel (49 in/px) in blue, green, red and near-infrared channels (450-510 nm, 510-580 nm, 655-690 nm and 780-920 nm, respectively).[3]

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References
  1. "WorldView 4 (WV 4, GeoEye 2)". Gunter's Space Page. Retrieved 19 March 2016.
  2. Ray, Justin (14 September 2016). "Idled by Range facility rework for months, Vandenberg ready to launch again Friday". Spaceflight Now. Retrieved 18 September 2016.
  3. "WorldView-4" (PDF). DigitalGlobe. November 2015. Archived from the original (PDF) on 24 April 2016. Retrieved 19 March 2016.
  4. Ray, Justin (11 November 2016). "Commercial satellite launched to image the Earth in high-resolution". Spaceflight Now. Retrieved 11 November 2016.
  5. "Launch Schedule". Spaceflight Now. 18 September 2016. Archived from the original on 19 September 2016.
  6. Henry, Caleb (2 December 2016). "DigitalGlobe releases first photo from WorldView-4". SpaceNews. Retrieved 3 December 2016.
  7. "GeoEye-2 (WorldView-4) Satellite Sensor (0.34m)". Satellite Imaging Corporation. Retrieved 19 March 2016.
  8. "WorldView-4 - Orbit". Heavens-Above. 14 November 2016. Retrieved 14 November 2016.
  9. "Primary Mirror Blank Assembly for GeoEye-2". GIM International. 11 June 2008. Retrieved 19 March 2016.
  10. "U.S. Department of Commerce Relaxes Resolution Restrictions, DigitalGlobe Extends Lead in Image Quality" (Press release). DigitalGlobe. 11 June 2014. Retrieved 19 March 2016.
  11. "DigitalGlobe loses WorldView-4 satellite to gyro failure". SpaceNews. 7 January 2019. Retrieved 23 February 2019.
  12. "GeoEye Initiates Development of its Third Generation Earth-Imaging Satellite" (Press release). GeoEye. PRNewswire. 18 October 2007. Retrieved 2 April 2016.
  13. "ITT awarded contract to build the Imaging System for the GeoEye-2 Earth-Imaging Satellite" (PDF) (Press release). ITT Corporation. 31 August 2010. Retrieved 2 April 2016.
  14. Ferster, Warren (11 March 2010). "Lockheed Martin Selected To Build GeoEye-2 Imaging Satellite". Space News. Retrieved 2 April 2016.
  15. Censer, Marjorie (3 May 2010). "GeoEye building satellite, awaits decision on major contract award". The Washington Post. Retrieved 2 April 2016.
  16. "GeoEye-2 completes design review". Dalje.com. United Press International. 1 July 2011. Retrieved 2 April 2016.
  17. "GeoEye-2's Design Phase Finishes Ahead of Schedule". Space News. 5 July 2011. Retrieved 2 April 2016.
  18. "GeoEye-2 Camera Passes Critical Design Review". Space News. 7 March 2011. Retrieved 2 April 2016.
  19. Lockwood, Irene (10 April 2012). "ITT Exelis delivers imaging system for next-generation, high-resolution GeoEye-2 satellite" (Press release). ITT Exelis. Retrieved 2 April 2016.
  20. Bergin, Chris (2 May 2012). "Lockheed Martin complete milestones on two upcoming spacecraft". NASA Spaceflight. Retrieved 2 April 2016.
  21. Tomesco, Frederic; Callan, James (23 July 2012). "DigitalGlobe Agrees to Acquire GeoEye for About $900 Million". Bloomberg. Retrieved 19 March 2016.
  22. Harden, Mark; Avery, Greg (31 January 2013). "DigitalGlobe completes GeoEye buy". Denver Business Journal. Retrieved 19 March 2016.
  23. Ray, Justin (4 February 2013). "One commercial Earth-imager deferred in favor of another". Spaceflight Now. Retrieved 19 March 2016.
  24. "DigitalGlobe Announces Second 30-Centimeter Satellite to Launch in Mid-2016" (Press release). DigitalGlobe. 31 July 2014. Retrieved 2 April 2016.
  25. Painter, Kristen Leigh (31 July 2014). "Demand moves DigitalGlobe to speed launch of high-powered satellite". The Denver Post. Retrieved 2 April 2016.
  26. Smith, Marcia S. (23 June 2012). "EnhancedView News Not so Rosy for GeoEye". Space Policy Online. Retrieved 28 June 2016.
  27. Henry, Caleb (4 November 2019). "Maxar announces GEO order, property sale and debt refinancing, sizes WorldView Legion at six satellites". SpaceNews. Retrieved 20 November 2019.
  28. Graham, William (11 November 2016). "Atlas V launches WorldView-4 out of Vandenberg". NASA Spaceflight. Retrieved 11 November 2016.
  29. Clark, Stephen (5 March 2016). "Fate of NASA's InSight Mars mission to be decided soon". Spaceflight Now. Retrieved 6 July 2016.
  30. Graham, William (18 September 2016). "Atlas V delays WorldView-4 launch from Vandenberg". NASA Spaceflight. Retrieved 18 September 2016.
  31. Hamm, Keith (29 September 2016). "Vandenberg Beats Back Four Separate Fires". Santa Barbara Independent. Retrieved 29 September 2016.
  32. Richardson, Derek (18 September 2016). "Nearby wildfire prompts delay in Atlas V launch". Spaceflight Insider. Retrieved 18 September 2016.
  33. "Launch of Atlas V Rocket with Worldview-4 Satellite Postponed Until October". Sputnik News. 22 September 2016. Retrieved 22 September 2016.
  34. Scully, Janene (27 September 2016). "Vandenberg AFB Beefs Up Security In Wake of Fires; Damage Still Unknown". Noozhawk. Retrieved 29 September 2016.
  35. Jacobson, Willis (28 September 2016). "VAFB commander addresses fires at town hall forum". Santa Maria Times. Retrieved 29 September 2016.
  36. Ray, Justin (25 October 2016). "California Atlas 5 launch that was delayed by wildfire finally rescheduled". Spaceflight Now. Retrieved 31 October 2016.
  37. "Atlas V to Launch WorldView-4". United Launch Alliance. 2 November 2016. Archived from the original on 3 November 2016.
  38. "Satellite: WorldView-4". World Meteorological Organization. 17 February 2016. Retrieved 19 March 2016.
  39. Harwood, William (11 November 2016). "Atlas 5 launches civilian imaging satellite". CBS News. Retrieved 14 November 2016.

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