Minimize WorldView-4

WorldView-4 (formerly GeoEye-2)

Spacecraft     Launch    Mission Status     Sensor Complement    References

In June 2014, Digital Globe announced that it received notice from the U.S. Department of Commerce on its application to allow the company to sell its highest-quality and industry-leading commercial satellite imagery. Effective immediately, DigitalGlobe was permitted to offer customers the highest resolution imagery available from their current constellation. Additionally, the updated approvals will permit DigitalGlobe to sell imagery to all of its customers at up to 0.25 m panchromatic and 1.0 m multispectral GSD (Ground Sample Distance) beginning six months after its next satellite WorldView-3 is operational. The launch of Worldview-3 is scheduled for August 2014. 1)

With the launch of WorldView-3, the DigitalGlobe constellation will set a new technological bar for commercial satellite imagery, offering customers the highest available resolution, revisit rate, capacity, and spectral diversity. The company currently operates a fleet of five high-resolution earth imaging satellites. Two of those satellites — GeoEye-1 and WorldView-2 — collect imagery sharper than 0.50 m, and all customers will have access to that imagery at the highest native resolution. WorldView-3 will provide even higher resolution at 0.31 m, and the GeoEye-2 satellite, which is substantially complete, will capture similarly sharp images when it is launched to replace a satellite currently in service or as an expansion to the constellation once warranted by market demand.

• GeoEye-2 is a third generation commercial satellite optical imaging mission of GeoEye Inc., Dulles, VA, USA. In January 2009, GeoEye awarded a contract to ITT Geospatial Systems of Rochester, N.Y. to start work on the imager for the GeoEye-2 spacecraft. 2)

• The requirements of GeoEye call for a spatial resolution of 25 cm of its imagery. Under current licensing constraints, only U.S. Government customers and specifically designated allies have access to imagery at this highest resolution while commercial customers receive imagery at the highest resolution allowed by U.S. regulations, currently at 0.5 m GSD (Ground Sample Distance).

• In March 2010, GeoEye Inc. awarded a contract to Lockheed Martin Space Systems to build the company's next-generation, high-resolution Earth imaging satellite system known as GeoEye-2. 3)

• In August 2010, NGA (National Geospatial-Intelligence Agency) awarded a contract, referred to as SLA (Service Level Agreement), to GeoEye within its Enhanced View program. The contract deals with the purchase of satellite imagery and includes also an NGA cost share for the development and launch of the GeoEye-2 spacecraft. Operational services of GeoEye-2 are scheduled for 2013. 4) 5)

• In early December 2010, GeoEye-2 successfully completed the program's Preliminary Design Review (PDR). 6)

• In January 2012, GeoEye-2 passed the system CDR (Critical Design Review).The spacecraft features CMGs (Control Moment Gyros) to provide an optimum of pointing agility for all observation modes. 7)

DigitalGlobe and GeoEye merged on January 31, 2013 to become one company, DigitalGlobe. On February 4, 2013, DigitalGlobe announced that its previously planned satellite construction program related to its third WorldView-class satellite remains on track. 8)

• In August 2014, DigitalGlobe announced its plans to accelerate the launch of WorldView-4, previously named GeoEye-2, to mid-2016 to meet demand from DigitalGlobe's Direct Access and other commercial customers. 9)

• DigitalGlobe launched its WorldView-3 spacecraft on August 13, 2014 to meet the requirements of its EnhancedView contract with the U.S. government. WorldView-3 offers the most spectral diversity available commercially and it is the first satellite to offer multiple short-wave infrared bands that allows for accurate imaging through haze, fog, dust, smoke and other airborne particulates. 10)

• In Dec. 2015, MDA (MacDonald , Dettwiler and Associates Ltd.) announced that it has signed a multi-million dollar contract with DigitalGlobe Inc. to provide multiple international ground stations with upgrades to receive and process imagery and data directly from DigitalGlobe's WorldView-4 satellite, in addition to the company's existing satellite constellation. After its planned launch in September 2016 , WorldView-4 will deliver multi-spectral high resolution optical imagery. 11)

Table 1: Some background on the GeoEye-2 / Worldview-4 development program 2) 3) 4) 5) 6) 7) 8) 9) 10) 11)




WorldView-4 will be DigitalGlobe's next very high resolution imaging satellite providing high resolution and color imagery to commercial, government and international customers. Lockheed Martin is the prime contractor of the WorldView-4 spacecraft. WorldView-4 will provide map-accurate images with a new, high-resolution camera provided by Harris Corporation. In addition to delivering critical geospatial situational awareness and global security information to intelligence analysts, war fighters and decision makers, commercial users will also benefit from access to imagery from WorldView-4. The satellite is fully integrated, tested and ready for launch call-up. 12)


Figure 1: Artist's rendition of the WorldView-4 spacecraft (image credit: Lockheed Martin, Digital Globe)

Spacecraft bus


Spacecraft mass

2,087 kg

Spacecraft size

5.3 m tall x 2.5 m across; 7.9 m across with deployed solar panels

Design life

7 years, (estimated service life: 10-12 years)

ADCS (Attitude Determination and Control Subsystem)

- 3-axis stabilization
- Actuators: CMGs (Control Moment Gyros)
- Sensors: Star trackers, precision IRU, GPS receiver

Retargeting agility

Time to Slew 200 km: 10.6 sec

Onboard storage capacity

3200 Gbit solid state memory with EDAC


- X-band downlink for image & ancillary data at 800 Mbit/s
- X-band for real-time housekeeping data at 120 kbit/s
- S-band for command data at 64 kbit/s

Max contiguous area collected in a single pass (30º off-nadir angle)

- Mono: 66.5 km x 112 km (5 strips)
- Stereo: 26.6 km x 112 km (2 pairs)

Revisit frequency (at 40º N latitude)

- 1 m GSD: < 1.0 day
- Total constellation >4.5 accesses/day

Geolocation accuracy (CE90)

Predicted <4 m CE90 without ground control

Observation capacity

680,000 km2 per day

Table 2: Some spacecraft/observation parameters


Figure 2: Photo of the WorldView-4, the world's second 30 cm imaging satellite, taken in July 2016 (image credit: DigitalGlobe) 13)


Development status:

• August 15, 2016: WorldView-4, which weighs 2,500 kg and stands 5.5 m tall, is "a big telescope with a little satellite wrapped around it," said Walter Scott, founder, chief technical officer and executive vice president of Westminster, Colorado-based DigitalGlobe. 14)

- WorldView-4 has taken an unusually long time to get to the launch pad. Lockheed Martin began building the satellite, originally named GeoEye-2 for GeoEye of Herndon, Virginia, in 2010. After DigitalGlobe and GeoEye merged in 2013, DigitalGlobe proceeded with its planned launch of WorldView-3 and opted to store GeoEye-2. DigitalGlobe renamed the GeoEye-2 satellite WorldView-4 in 2014 when the company announced its 2016 launch.


Figure 3: Photo of the WorldView-4 spacecraft. Employees at Lockheed Martin completing final preparations of the WorldView-4 imaging satellite (image credit: Lockheed Martin)

• On July 28, 2016, the WorldView-4 satellite arrived at VAFB after a 250-mile trip (from Sunnyvale, CA) in a cleanroom-on-wheels. The Lockheed Martin-built WorldView-4 was transported by truck in a special container that mimics the environment of the cleanroom where the satellite was manufactured. 15)

- Prior to shipping, the satellite passed a full suite of environmental, functional and performance tests and was declared ready for integration with the rocket that will carry it to an altitude of 617 km in space.


Figure 4: Photo of the "cleanroom transport" with WorldView-4 aboard leaving the Lockheed facility in Sunnyvale, CA (image credit: Lockheed)


Launch: The WorldView-4 (former GeoEye-2) spacecraft was launched on November 11, 2016 (18:30 UTC) on an Atlas-V 401 vehicle of ULA (United Launch Alliance) from VAFB, CA, SLC-3E (Space Launch Complex-3East). 16) 17) 18)

The launch of WorldView-4 had to be cancelled on the original launch date of September 18 due to an extremely aggressive fire that consumed some 12,000 acres (4840 hectar) across Vandenberg's South Bases. This was considered to be the largest fire in the base' history but, fortunately, the space launch complexes and other facilities remained clear of the destruction. — All of the 200 miles of cabling have now been certified as in order by the 30th Space Communications Squadron of the US Air Force, and all appears to be a "go" for this delayed and now re-scheduled launch (Ref. 18).


Orbit: Sun-synchronous orbit, altitude = 617 km, inclination = 98º, period = 97 minutes, LTDN (Local equatorial crossing Time on Descending Node) at 10:30 hours, effective revisit time capability ≤ 3 days.

Secondary payloads: 19)

DigitalGlobe has included a CubeSat rideshare program. The CubeSats will be launched by use of ULA's Centaur Aft Bulkhead Carrier that has flown successfully on four previous Atlas V missions. All of the 7 CubeSats manifested for the WorldView-4 mission are sponsored by the U.S. NRO (National Reconnaissance Office) and are unclassified technology demonstration programs. DigitalGlobe is also partnering with California Polytechnic State University, Tyvak Nanosatellite Systems Inc., Lockheed Martin and United Launch Alliance to bring this rideshare program to fruition.

Tyvak Nanosatellite Systems (Irvine, CA) served as the integrator for all seven CubeSats. ENTERPRISE is the fifthNRO mission to utilize ridesharing, but the first in which the organization has partnered with a commercial company to do so. 20)

• CELTEE-1 (CubeSat Enhanced Locator Transponder Evaluation Experiment-1), a 1U CubeSat built by M42 Technologies (Seattle,WA) for AFRL (Air Force Research Laboratory). The goal is to test the performance of an ELT (Enhanced Location Transponder) in support of SSA (Space Situational Awareness).

• Prometheus-2 x 2, two 1.5U technology demonstration CubeSats (Block 2) of LANL (Los Alamos National Laboratory). Test of communications between remote field sites and ground station terminals in a store-and-forward environment.

• AeroCube-8C and -8D, two 1.5U technology demonstration CubeSats of the Aerospace Corporation (El Segundo, CA) to test electric propulsion, CNT (Carbon Nanotubes) and solar cell technology.

• U2U (Untitled 2U), a 2U CubeSat of AFRL to demonstrate the EGM (Electron and Globalstar Mapping) experiment.

• RAVAN (Radiometer Assessment using Vertically Aligned Nanotubes), a 3U CubeSat mission funded by the NASA and developed and operated by JHU/APL.

The CubeSats will be deployed after WorldView-4 separation as part of the NRO-sponsored ENTERPRISE mission.


Figure 5: Illustration of the deployed WorldView-4 spacecraft (DigitalGlobe)



Mission status:

• May 6, 2019: Maxar Technologies has announced that the company's insurance carriers have accepted the company's $183 million claim for loss arising from the WorldView-4 satellite on-orbit failure and have agreed to pay the company that full amount under their insurance policies. 21)

- Insurance proceeds have already been received from several insurers and full payment is expected to be delivered within 30 days. Maxar will use the proceeds to invest in its pre-existing capital priorities, including the development of its innovative WorldView Legion constellation.

- The operations of DigitalGlobe, SSL and Radiant Solutions were unified under the Maxar brand in February; MDA continues to operate as an independent business unit within the Maxar organization.

January 7, 2019: Maxar Technologies Inc. today reported that its WorldView-4 satellite experienced a failure in its CMGs (Control Moment Gyros), preventing the satellite from collecting imagery due to the loss of an axis of stability. 22)

- Efforts are ongoing in conjunction with its suppliers in an attempt to restore satellite functionality, but thus far these efforts have been unsuccessful. At this time, Maxar believes that WorldView-4 will likely not be recoverable and will no longer produce usable imagery. Maxar operations has put the WorldView-4 satellite in a safe configuration and will continue to monitor the satellite's location and health. The satellite was built by Lockheed Martin and the CMGs were provided by Honeywell.

- WorldView-4 was acquired by GeoEye prior to its merger with DigitalGlobe in 2013. It was launched in November 2016 and generated revenues of approximately $85 million in fiscal year 2018. The satellite had a net book value of approximately $155 million, including related assets, as of December 31, 2018. If the satellite is not recoverable, then the net book value will be written off in Q4-2018. Contingency planning and mitigation efforts are underway to assess the use of the Company's other satellites and outside resources to replace imagery collected by WorldView-4 and meet as much of the existing customer commitments and obligations as possible. The Company currently believes it will be able to offset $10 to 15 million of the annual revenue from WorldView-4 and will work to minimize the potential impact on Maxar's financial results in future years.

- The WorldView-4 satellite is insured for $183 million, and Maxar intends to seek full recovery for the loss of WorldView-4 under its insurance policies. The Company will provide further updates on this matter as new information becomes available.

October 04, 2018: NASA has launched a pilot program to evaluate how Earth science data from commercial small-satellite constellations could supplement observations from the agency's fleet of orbiting Earth science missions. On 28 September, the agency awarded sole-source contracts to acquire test data sets from three private sector organizations. 23)

- NASA's Earth Science Division in Washington issued blanket purchase agreements for the "Private Sector Small Constellation Satellite Data Product Pilot" program. Under these agreements, the agency purchases data sets and related products based on observations derived from Earth-orbiting, small-satellite constellations designed and operated by non-governmental entities.

- "This pilot program is an innovative and efficient way for us to acquire, examine, and evaluate a wide range of private sector Earth observation data," said Michael Freilich, director of NASA's Earth Science Division. "As our very capable NASA research satellite fleet ages and more small satellites are launched by private industry, there are opportunities to leverage the strengths of each into even more complete climate data sets."

- NASA will provide the test data products to NASA-funded researchers, who will examine whether the data help advance the agency's science and applications development goals. The pilot program is designed to determine whether these private sector observations and associated products offer a cost-effective means to augment or complement the suite of Earth observations acquired directly by NASA, other U.S. government agencies, and international partners.

- The contracts were awarded to:

1) DigitalGlobe, a Maxar Technologies company headquartered in Westminster, Colorado, has five very high-resolution Earth imaging satellites (GeoEye-1, WorldView-1, WorldView-2, WorldView-3, WorldView-4) capable of collecting 30 cm resolution imagery.

2) Planet, headquartered in San Francisco, has three satellite constellations (SkySat, Dove, RapidEye) with more than 150 satellites supplying imagery and derived products over the entire Earth at medium and high resolution with high repeat frequencies.

3) SPIRE Global, headquartered in San Francisco, operates a constellation of over 60 Lemur 3U CubeSats collecting radio occultation soundings, aircraft location information and ship reports. GPS radio occultation measurements can be used to sound the atmosphere for temperature, water vapor, and atmospheric pressure.

- These contracts represent the first time that NASA has engaged with commercial small-satellite constellation operators to purchase their data for scientific evaluation. They establish a way for NASA to acquire and examine the data products during the next 12 months. Each contract includes an option for NASA to extend the agreement for an additional four years, for a total value of up to $7 million for each of the three agreements.

- To be considered for participation in this pilot program, companies had to demonstrate they were currently operating a small satellite constellation of no fewer than three satellites in non-geostationary orbit and producing consistent global coverage. Companies also were asked to supply a comprehensive catalog of their data, describing areal coverage, data latency, pricing, and other factors.

- NASA uses the vantage point of space to understand and explore our home planet, improve lives and safeguard our future. The agency's observations of Earth's complex natural environment are critical to understanding how our planet's natural resources and climate are changing now and could change in the future.

• April 22, 2018: DigitalGlobe, a Maxar Technologies company, formerly MDA (MacDonald, Dettwiler and Associates Ltd.), announced today that with the complete integration of DigitalGlobe's WorldView-4 satellite imagery into SecureWatch, the company's powerful, cloud-based geospatial intelligence (GEOINT) platform, customers can now access more of the world's highest resolution satellite imagery. 24)

- WorldView-4's daily imagery collections more than double SecureWatch's daily volume of valuable 30 cm imagery, enhancing defense and intelligence analysts' ability to closely monitor activity in their areas of interest. WorldView-4 collection plans are constantly analyzed and improved to deliver more refreshed 30 cm imagery over the rapidly changing geographies that SecureWatch customers need to make mission-critical decisions with confidence.

- The subscription-based platform will expand further this summer when RADARSAT-2 imagery from MDA, another Maxar company, becomes available. MDA's RADARSAT-2 SAR (Synthetic Aperture Radar) imagery will expand the capacity for analysts to monitor key locations around the world, regardless of weather and light conditions.

- When layering radar and optical imagery together, an analyst can quickly flag areas of change and develop richer situational reports. The planned addition of MDA's RADARSAT-2 imagery into DigitalGlobe's SecureWatch product is yet another example of how Maxar is extending cross-business technology to accelerate innovation and offer integrated solutions to customers.

- "The combination of RADARSAT-2 imagery and DigitalGlobe's optical imagery, with the other enriched data sources within SecureWatch, will create powerful solutions for analysts to maintain situational awareness and achieve mission success no matter what's happening on the planet," said Jeff Kerridge, Senior Vice President and General Manager of DigitalGlobe International Defense and Intelligence.

- DigitalGlobe also celebrates the signing of its 20th SecureWatch defense and intelligence agency customer since launching the product in February 2017. The first 10 customers started using SecureWatch before the end of 2017 and another 10 have also subscribed this year, joining defense and intelligence analysts around the world who rely on complete access to both DigitalGlobe's 18-year, 100 petabyte imagery archive and the over three million square kilometers of fresh high-resolution imagery added daily.

- "DigitalGlobe is proud to be the trusted partner to 20 SecureWatch subscribers, 70% of whom are new to DigitalGlobe, who understand the demonstrated value of allowing us to help hundreds of analysts deliver GEOINT that is rich, accurate and current," added Kerridge.

- New features within SecureWatch are routinely released to improve user experience by putting more GEOINT sources at analysts' fingertips, in addition to the tools to analyze and exploit the data contained within those sources.

• On December 15, 2017 at 15:36 GMT, SpaceX launched the NASA commercial resupply service mission CRS-13 to the ISS on a Falcon-9 FT vehicle from Cape Canaveral SLC-40. - After the launch, SpaceX landed the first stage of the Falcon-9 vehicle upright on solid ground at Cape Canaveral, Florida. SpaceX has now managed to return 20 of its rocket boosters after launch, whether on land or on a floating ocean platform, as part of its effort to re-use instead of jettison costly components. 25)

- Worldview-4 of DigitalGlobe was in the right orbital position to capture an image of SpaceX's first stage (Figure 6) in upright position just minutes after its landing at Cape Canaveral (Ref. 26).


Figure 6: WorldView-4, captured this image at 10:49 a.m. EST (15:49 GMT) on 15 Dec. 2017, just minutes after the Falcon 9 first stage booster returned to Earth with a flawless landing. A launch crew can be seen hosing down the rocket (image credit: Matthew Flannery, DigitalGlobe) 26)

October 5, 2017: MDA (MacDonald, Dettwiler and Associates Ltd.) of Richmond, BC, Canada, a global communications and information company providing technology solutions to commercial and government organizations worldwide, today announced it has completed its acquisition of DigitalGlobe, Inc. ("DigitalGlobe"), the global leader in high resolution Earth imagery and information about our changing planet. The merger creates the leading integrated commercial provider of satellites, imagery and geospatial solutions to commercial and government customers worldwide. The newly combined company will offer a broader set of space-based solutions, increased scale and a more diversified revenue base.

New Corporate Name: MDA also announced today that it will become Maxar Technologies Ltd., and its U.S.-headquartered operating company, SSL MDA Holdings, Inc., will become Maxar Technologies Holdings Inc. The new Maxar Technologies launches a distinctive group of leading space brands, technologies and capabilities.

Canada-based MDA and U.S.-based DigitalGlobe overcame an extended review by the Committee on Foreign Investment in the United States (CFIUS) after refiling merger paperwork in July. The inter-agency committee, which reviews potential national security risks from foreign buyers of American businesses, ultimately found no issue with the merger.

MDA Corp.'s president and chief executive Howard Lance stated: "Maxar Technologies encompasses four of the leading commercial space technology brands—SSL, MDA, DigitalGlobe and Radiant—and represents the expanded benefits and value we will offer to our customers, shareholders, partners and employees."

With the addition of DigitalGlobe and Radiant Solutions, the Maxar Technologies portfolio of best-in-class brands offers a full suite of end-to-end solutions capabilities with deep domain expertise and space heritage.

- SSL: the leading commercial provider of communications and Earth observation satellites and scientific mission spacecraft for commercial and government markets

- MDA: an internationally recognized leader in space robotics, satellite antennas and subsystems, surveillance and intelligence systems, defense and maritime systems and geospatial radar imagery

- DigitalGlobe: the global leader in high resolution optical satellite imagery and information about our changing planet; and

- Radiant: a highly specialized provider of geospatial data, analytics, software and services to facilitate insights and intelligence where and when it matters most.

Table 3: Acquisition of DigitalGlobe by MDA 27) 28)

• September 2017: WorldView-4 Launch and Calibration Timeline: 29)

- Launch: 11 November 2016

- First image: 21 November 2016

- Relative radiometric calibration: 03 December 2016

- Geometric camera calibration: 12 December 2016

- Geometric accuracy: 1 February 2017

- Absolute radiometric calibration: 8 February 2017.

• September 2017: DigitalGlobe's Future Constellations: 30)


Figure 7: Our future DG constellation will diversify our capabilities (image credit: Digital Globe)


Figure 8: Our DG constellation roadmap will extend our industry leadership well into the next decade (image credit: DigitalGlobe)

• August 15, 2017: Digital Globe today announced that it signed a DAP (Direct Access Program) contract with the Australian Department of Defence. This multi-year agreement will allow the Australian government to access DigitalGlobe's industry-leading commercial satellite imaging constellation to support defense and intelligence missions. The contract is expected to deliver $83.0 million USD in incremental revenue to DigitalGlobe over four years, beginning in January 2018. 31)

- As a DAP partner, the Australian Department of Defence will be able to directly task and download imagery in real-time to its ground station from all five DigitalGlobe satellites—including WorldView-4, launched in November 2016, and WorldView-3, launched in August 2014, which are the world's two highest-resolution commercial satellites. The addition of Australia—a key ally of the U.S. and member of the Five Eyes intelligence alliance—expands the global footprint of DigitalGlobe's DAP program and reflects the Australian government's commitment to increase the use of commercial satellite imagery for its critical national defense and intelligence missions.

• April 18, 2017: EUSI (European Space Imaging) announced that the company has launched its new ground station with access to the entire fleet of its WorldView Global Alliance DigitalGlobe partner. The Munich-based company is now able to directly handle five high resolution satellites (GeoEye-1, WorldView-1, WorldView-2, WorldView-3 and WorldView-4). This speeds up the whole process of planning, collection, data downlink and delivery and allows European Space Imaging to quickly deliver satellite imagery products to WorldView Global Alliance customers in Europe, North Africa, CIS (Commonwealth of Independent States) countries and the Middle East. 32)

- "The capabilities of our new ground station and the direct access to the entire DigitalGlobe satellite fleet start a new era in the availability of highest resolution imagery in Europe. It's a major milestone especially in the 30 cm resolution class", says Adrian Zevenbergen, Managing Director of European Space Imaging. "In 2017, we plan to collect more than two times the entire European land mass with the 30 cm satellite constellation alone."


Figure 9: Sample WorldView-4 image of the Istanbul Airport, acquired on March 29, 2017 (image credit: EUSI, DigitalGlobe)


Figure 10: Sample WorldView-4 image of the Leaning Tower of Pisa, Italy, acquired on March 28, 2017 (EUSI, DigitalGlobe)

• February 6, 2017: The WorldView-4 commercial satellite, operated by DigitalGlobe, Inc., has successfully completed on orbit testing and calibration and started to serve the company's first direct access customer on February 1, 2017. 33) 34)

- WorldView-4, launched on November 11, 2016, becomes the fifth active satellite in DigitalGlobe's constellation of high-resolution Earth observation satellites. The satellite's performance meets the industry-leading quality standards of the WorldView fleet and joins WorldView-3 as the world's only commercial satellites capable of achieving 30 cm native resolution. Imagery with this level of detail enables users to reliably read street markings, distinguish between cars, trucks, and vans, and confidently understand activities of significance, as demonstrated by a recent SkyTruth analysis that used WorldView-3 imagery to document the likely transshipment of fish by Southeast Asian vessels in the Indian Ocean.

- The satellite more than doubles DigitalGlobe's capacity to collect 30 cm imagery, enhancing the company's ability to meet the most demanding commercial use cases, such as complementing aerial imagery collection strategies, and enabling the creation of high-quality, imagery-derived products, such as high-resolution 3D models and near-seamless, country-scale basemaps.


Figure 11: Sample image of Brasilia, the Capital of Brazil, acquired with WorldView-4 on January 11, 2017 (image credit: Digital Globe)


Figure 12: Sample WorldView-4 image of Subi Reef, acquired on Dec. 27, 2016 (image credit: DigitalGlobe)

Legend to Figure 7: Subi Reef (also Zhubi Reef) is a reef in the Spratly Islands of the South China Sea located 26 km southwest of Philippine-occupied Thitu Island. It is occupied by China, and claimed by Taiwan, Vietnam, and the Philippines. It currently falls under the jurisdiction of Nansha islands, Sansha city, Hainan province, China. The atoll measures 5.7 km along its longer southwest-northeast axis, and is up to 3.5 km wide. Its total area including the lagoon and rim of the reef measures 16 km2, and the lagoon is up to 22 meters deep. 35)

• December 5, 2016: DigitalGlobe has released the first image from the company's WorldView-4 satellite, launched on Nov. 11, 2016. 36)


Figure 13: WorldView-4's first public image, taken on November 26, 2016, features the Yoyogi National Gymnasium in Shibuya, Tokyo. The site hosted events during the 1964 Olympic Games and will again host international competition when the games return to Tokyo in 2020 (image credit: DigitalGlobe)

• WorldView-4 is the new companion to WorldView-3, effectively doubling the amount of best-on-the-market imagery with unmatched 30 cm resolution. WorldView-3 is booked by U.S. government contracts. WorldView-4 will enable DigitalGlobe sales to foreign allies and commercial uses like agriculture, mining, land developers and oil and gas firms.



Sensor complement: (SpaceViewTM 110)

SpaceViewTM 110 Imaging System:

WorldView-4 will enable expanded capability in the collection of sub-meter imagery to help solve real-world problems. The Harris SpaceView™ line of optical imaging systems offers a broad spectral range of high-resolution optical payloads. The SpaceView™ 110 solution for WorldView-4 will provide the highest resolution satellite imagery commercially available. 37)

The SpaceViewTM 110 payload serves as the imaging payload for DigitalGlobe's WorldView-3 and WorldView-4 satellites. Delivering up to 25 cm panchromatic resolution, SpaceViewTM 110 boasts the most advanced capabilities available from an imaging payload on the market today.

Scanning at 24,000 lines/second, the SpaceView 110 imaging payload is capable of providing an image spanning from London to Paris in just 45 seconds. This feature enables users to understand what is happening over a long distance as soon as possible.

Note: In May 2015, Harris Corp. of Melbourne, FL. acquired ITT Exelis Inc. of Fort Wayne, IN. 38)

ITT Corporation of Rochester, N.Y. received a subcontract from Lockheed Martin Space Systems to continue building the imaging system for GeoEye's next-generation Earth-imaging satellite, GeoEye-2, ITT announced on August 31, 2010. 39)

On March 1, 2011, ITT announced that it has satisfied a key milestone with the successful completion of the CDR (Critical Design Review) for the imaging system for GeoEye-2. 40)

In 2011, ITT Corporation's board of directors approved a plan to separate the company's businesses into three distinct, publicly traded companies. As of Oct. 31, 2011, ITT Exelis is the company involved in C4ISR (Command, Control, Communications, Computers, Intelligence, Surveillance and Reconnaissance) related products and systems and information and technical services. This pertains also to space systems.

In April 2012, ITT Exelis Geospatial Systems has delivered GeoEye's next-generation commercial imaging system for the GeoEye-2 satellite to Lockheed Martin Space Systems Company in Sunnyvale, CA. The instrument provides a GSD (Ground Sample Distance) of 34 cm for panchromatic imagery and 1.36 m for multispectral imagery from an orbit of 681 km. 41)

WorldView-4 will provide map-accurate images with a new, high-resolution camera provided by Harris Corporation. In addition to delivering critical geospatial situational awareness and global security information to intelligence analysts, war fighters and decision makers, commercial users will also benefit from access to imagery from WorldView-4.

WorldView-4 is a multispectral, high-resolution commercial satellite of DigitalGlobe.The SpaceView 110 instrument has a telescope of 1.1 m in diameter ; it will provide imagery of 31 cm in panchromatic resolution and 1.24 m in multispectral resolution from an orbit of 617 km. 42) 43)

Spectral bands


450 - 800 nm

Multispectral (4 bands)

450 - 510 nm (blue)
510 - 580 nm (green)
655 - 690 nm (red)
780 - 920 nm (NIR)

GSD (Ground Sample Distance)

Panchromatic nadir
20º off-nadir, 56º off-nadir, 65º off-nadir (Earth limb)

0.31 m
0.34 m, 1.00 m, 3.51 m

Multispectral nadir
20º off-nadir, 56º off-nadir, 65º off-nadir (Earth limb)

1.24 m
1.38 m, 4.00 m, 14.00 m

Data quantization

11 bit/pixel

Swath width

13.1 km at nadir

Instrument aperture

110 cm diameter

Instrument mass

470 - 550 kg

Imaging power

925 - 1100 W

Resolution @ 500 km (GSD)

0.25 - 0.30 m

Sensor capabilities

• Staring
• Scanning
• Motion Imagery / Video
• Low Light

Table 4: Parameters of SpaceView 110 on WorldView-4

SpaceView 110 features:

- Industry-leading geolocation accuracy (predicted <4 m CE90 without ground control)

- High capacity in various collection modes

- Bi-directional scanning

- Rapid retargeting agility using Control Moment Gyros (>2x faster than any competitor) resulting in superior area and point target collection capability. Time to Slew 200 km: 10.6 seconds.

- Direct access tasking from and image transmission to customer sites

- Daily revisit capability.


Figure 14: GSD (Ground Sample Distance) of the SpaceView 110 imager in relation to orbital altitude (image credit: Harris)







Operational altitude

496 km

681 km

770 km

617 km

617 km

Spectral characteristics




Pan + 8 MS + 8 SWIR

Pan + 4 MS

Panchromatic resolution (nadir)

0.50 m

0.41 m

0.46 m

0.31 m

0.31 m

Multispectral resolution (nadir)


1.64 m

1.85 m

1.24 m

1.24 m

Accuracy specification (nadir)

6.5 m CE90

3 m CE90

6.5 m CE90

3.5 m CE90

4 m CE90

Swath width

17.7 km

15.3 km

16.4 km

13.2 km

13.1 km

Average revisit at 40ºN latitude

1.7 days

<3 days

1.1 days

1.0 days

1.0 days

Monoscopic area coverage (30º off-nadir)

111 km x 112 km
(6 Strips)

45 km x 112 km
(3 Strips)

138 km x 112 km
(8 Strips)

69 km x 112 km
(5 Strips)

66.5 km x 112 km
(5 Strips)

Single-pass stereoscopic coverage (30 off-nadir)

51 km x 112 km
(3 Pairs)

15 km x 112 km
(1 Pair)

63 km x 112 km
(4 Pairs)

28 km x 112 km
(2 Pairs)

26.6 km x 112 km
(2 Pairs)

Weight class of spacecraft

2500 kg

1955 kg

2800 kg

2800 kg

2600 kg

Attitude control actuators


Reaction wheels




Onboard storage capacity

2199 Gbit

1000 Gbit

2199 Gbit

2199 Gbit

3200 Gbit

Wideband data downlink rate

800 Mbit/s total

740 Mbit/s total

800 Mbit/s total

800 or 1200 Mbit/s total

800 Mbit/s total

Rapid delivery options

Direct Downlink, Virtual Ground Terminal

Table 5: Overview of the DigitalGlobe constellation 44)


Figure 15: Illustration of the SpaceViewTM 110 instrument (image credit: Harris)


Figure 16: Pictorial view of the DigitalGlobe constellation of high-resolution imagery (image credit: DigitalGlobe)


1) "U.S. Department of Commerce Relaxes Resolution Restrictions DigitalGlobe Extends Lead in Image Quality," DigitalGlobe, June 11, 2014, URL:

2) "GeoEye-2 the World Highest Resolution Satellite in Development," URL:

3) "Lockheed Martin Wins Contract To Build GeoEye-2," Space Daily, March 12, 2010, URL:

4) "GeoEye Wins $3.8 Billion National Geospatial-Intelligence Agency EnhancedView Award," GeoEye, Aug. 9, 2010, URL:

5) "GeoEye Wins National Geospatial-Intelligence Agency Enhanced View Award," Space Daily, Aug. 10, 2010, URL:

6) "Lockheed Martin Team Completes GeoEye-2 Preliminary Design Review Ahead of Schedule," Lockheed Martin, Dec. 6, 2010, URL:

7) David Mulawa, "GeoEye Geolocation Assessment and Reporting Update for 2011," Proceedings of the 11th Annual JACIE (Joint Agency Commercial Imagery Evaluation ) Workshop, Fairfax, Va, USA, April 17-19, 2012, URL:

8) "DigitalGlobe's WorldView-3 Satellite Continues on Track for Mid-2014 Launch - Company Will Complete GeoEye-2 Satellite to Preserve as Ground Spare," DigitalGlobe Press Release, Feb. 4, 2013, URL:

9) "DigitalGlobe—Accelerating The Launch + A Name Change (Satellite—Launch Preparations)," Satnews Daily, August 1, 2014, URL:

10) "United Launch Alliance Atlas V Launches WorldView-3 Satellite for DigitalGlobe," ULA, Aug. 13, 2014, URL:

11) "MDA to provide ground stations with direct access to DigitalGlobe's WorldView-4 satellite," MDA Press Release, Dec. 10, 2015, URL:

12) "WorldView-4," Lockheed Martin, 2016, URL:


14) Debra Werner, "WorldView-4's long road to launch 
about to pay off for DigitalGlobe," Space News Magazine, August 15, 2016, URL:

15) "Countdown to Launch: WorldView-4 Earth Imaging Satellite Arrives at Vandenberg Air Force Base for Sept. 15 Launch," Lockheed Martin, July 28, 2016, URL:

16) "ULA launches latest DigitalGlobe commercial earth observation satellite WorldView-4," Space Daily, Nov. 14, 2016, URL:

17) "Lockheed Martin Successfully Launches WorldView-4 Satellite for DigitalGlobe," Lockheed Martin, Nov. 11, 2016, URL:

18) "A Wending Its Way November 6th Launch Date Set For WorldView 4," Satnews Daily, Oct. 26, 2016, URL:

19) "WorldView-4's Atlas V launch vehicle to carry seven CubeSat missions for NRO," DigitalGlobe, July 25, 2016, URL:

20) "Tyvak Facilitates First NRO CubeSat Mission Aboard Non-Governmental Launch," Tyvak, Nov. 11, 2016, URL:

21) "Maxar Technologies to Receive Full Insurance Coverage for the Firm's WorldView-4 On-Orbit Failure," Satnews Daily, 6 May 2019, URL:

22) "Maxar Technologies Reports Failure of its WorldView-4 Imaging Satellite," Maxar Technologies, 7 January, 2019, URL:

23) Steve Cole, "NASA Evaluates Commercial Small-Sat Earth Data for Science," NASA Release 18-086, 04 October 2018, URL:

24) "Maxar Technologies' DigitalGlobe Integrates Highest Resolution Satellite Imagery from WorldView-4 into SecureWatch," SpaceRef, 22 April 2018, URL:

25) "In first, SpaceX launches recycled rocket and spaceship," Space Daily, 15 Dec. 2017, URL:

26) "DigitalGlobe Documents SpaceX's Successful 'Firsts' Times Two Includes Hosing Down a Falcon," Satnews Daily, 18 Dec. 2017, URL:

27) "MDA Completes Acquisition of DigitalGlobe, Creates Industry Leader in Satellite Systems, Earth Imagery, Geospatial Solutions and Analytics," MDA Press Release, Oct. 5, 2017. URL:

28) Henry Caleb, "MDA closes DigitalGlobe merger, rebrands as Maxar Technologies," Space News, Oct. 5, 2017, URL:

29) Chris Comp, David Mulawa, Brendan Clarke, Todd Updike, "WorldView-4 calibration - DigitalGlobe Constellation Update," JACIE (Joint Agency Commercial Imagery Evaluation) Workshop, Reston, VA, USA, Sept. 19-21, 2017, URL:

30) "DigitalGlobe Satellite and Product Overview," JACIE (Joint Agency Commercial Imagery Evaluation) Workshop, Reston, VA, USA, Sept. 19-21, 2017, URL:

31) "DigitalGlobe Announces Four-Year Direct Access Contract with the Australian Department of Defence for Real-time Access to the World's Highest-Resolution Commercial Satellite Imagery," Business Wire, 15 Aug. 2017, URL:

32) "European Space Imaging starts commercial distribution of WorldView-4 satellite imagery in Europe," EARSC (European Association of Remote Sensing Companies), April 18, 2017, URL:

33) "WorldView-4 enters service," DigitalGlobe, Feb. 1, 2017, URL:

34) "WorldView-4 Is Up and Capturing," Satnews Daily, Feb. 6, 2017, URL:

35) "Subi Reef," Wikipedia, URL:

36) "WorldView-4 first image, " DigitalGlobe, URL:

37) "SpaceView 110 Satellite Imaging Solution," Harris, URL:

38) "Harris Corporation Completes Acquisition of Exelis," Press Release, May 29, 2015, URL:

39) "ITT awarded contract to build the Imaging System for the GeoEye-2 Earth-Imaging Satellite," August 31, 2010, URL:

40) "ITT's Next-Generation Imaging Payload Passes Major Milestone," March 1, 2011, URL:

41) "ITT Exelis delivers imaging system for next-generation, high-resolution GeoEye-2 satellite," Space Daily, April 11, 2012, URL:

42) "WorldView-4 Data Sheet," Digital Globe, Nov. 15, 2015, URL:

43) "WorldView-4 Data Sheet," Digital Globe, URL:

44) "The DigitalGlobe Constellation," DigitalGlobe brochure, 2016, URL:


The information compiled and edited in this article was provided by Herbert J. Kramer from his documentation of: "Observation of the Earth and Its Environment: Survey of Missions and Sensors" (Springer Verlag) as well as many other sources after the publication of the 4th edition in 2002. - Comments and corrections to this article are always welcome for further updates (

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