Orbcomm (satellite)

Orbcomm satellites are low Earth orbit communications satellites, operated by the United States satellite communications company Orbcomm. As of July 2014, 51 such satellites have orbited Earth, with 50 still continuing to do so.

Satellite types

Orbcomm-CDS

Orbcomm-CDS (Concept or Capability Demonstration Satellites) are spacecraft which were launched to test equipment and communication techniques used by the other satellites. The first three CDS satellites, Orbcomm-X, CDS-1 and CDS-2, were launched before any operational satellites, in order to validate the systems to be used in the operational constellation.

Orbcomm-X, also known as Datacomm-X, was launched in 1991. It carried communications and GPS experiments. Initially, the spacecraft was reported healthy, but communication was lost after just one orbit.^[1]

CDS-3 was launched in 2008, along with the 5 Quick Launch satellites. It contained experiments for relaying signals from the United States Coast Guard Automatic Identification System through the satellite constellation.^[2] It was designated Orbcomm FM-29,^[2] having most of the communications payload from an unlaunched satellite. The avionics bus to that satellites later became TacSat-1.

Orbcomm-OG1

Orbcomm-1 satellites make up most of the current Orbcomm constellation. 36 were built, of which 35 were launched, and one more, Orbcomm FM-29, was rebuilt as TacSat-1 for the United States military.^[3]

Orbcomm-QL

Orbcomm Quick Launch (QL) satellites are satellites which were intended to replenish the constellation. The first five such satellites were launched in 2008, with one more planned, but never launched. The satellites are based on the CDS-3 satellite, which was launched on the same rocket as the first five QL spacecraft. The sixth will be launched as a secondary payload to a Russian Government satellite, also on a Kosmos-3M. Orbcomm holds options for two further satellites.^[4] The satellites experienced a power system anomaly, and Orbcomm filed an insurance claim on the satellites for $50 million.^[5] Orbcomm reported in 2011 that the last remaining Quick Launch satellite had failed.^[6]

Orbcomm-OG2

SpaceX's Falcon 9 rocket launched the ORBCOMM OG2 Mission 1 on July 14, 2014.

Orbcomm Generation 2 (OG2) second-generation satellites are intended to supplement and eventually replace the current first generation constellation. Eighteen satellites were ordered by 2008—nominally intended to be launched in three groups of six during 2010–2014—and by 2015 have all been launched, on three flights. Orbcomm has options for a further thirty OG2 spacecraft.^[8] The satellites were launched by SpaceX on the Falcon 9 launch system. Originally, they were to launch on the smaller Falcon 1e rocket.^[9]

The first of these satellites was launched on 7 October 2012 as secondary payload on a SpaceX Falcon 9 v1.0 flight. The primary payload was for NASA to the ISS.^[10][11] On this launch the Falcon 9 had a failure in one of its nine first stage engines 79 seconds after liftoff from Cape Canaveral, Florida. This prevented the OG2 prototype satellite from being deployed into the proper orbit.^[12] The satellite functioned as planned during the short time it was in orbit. This allowed a subset of spacecraft systems to be flight-test validated. The orbit of the spacecraft was unable to be raised to a sustainable altitude due to contractual limitations put on SpaceX by the primary payload owner, NASA. Two days after its launch the OG2 prototype re-entered and burned up in Earth's atmosphere. Orbcomm claimed the mission a total loss for launch insurance purposes.^[13][14]

The second launch, with a constellation of six OG2 satellites, launched on July 14, 2014.^[7][15] The satellites were launched on a SpaceX Falcon 9 v1.1 launch vehicle. Following the end of the use of the first stage for the Orbcomm orbital mission, SpaceX used the booster stage—which would ordinarily be destroyed on reentering the Earth's atmosphere and impact with the ocean—for a flight test of a number of reusable launch vehicle technologies to safely reenter and execute a "soft vertical landing" on the ocean surface, where it successfully decelerated, made a successful reentry, landing burn and deployment of its landing legs. The first stage was not recovered as the hull integrity was breached on landing or on the subsequent "tip over and body slam".^[16]

The third launch, with the final 11 second-generation OG2 satellites, was successfully completed December 21, 2015.^[17] It was initially scheduled for late-2014, but ORBCOMM delayed the launch until at least mid-2015^[18] finally resetting the launch timeframe to mid-August through late-September 2015.^[19] The launch date was further delayed by the rocket failure on the SpaceX Falcon 9 Flight 19 launch in June 2015, which ultimately delayed the OG2 launch further out to late 2015.^[17][20] The satellites were placed by the Falcon 9 launch vehicle "within a fraction of a degree in inclination and 5 kilometers (3.1 mi) in altitude of the intended orbit," and by 9 January 2016, were in the middle of on-orbit testing, while executing propulsion maneuvers that had spread the 11 satellites over a 6,400-kilometer (4,000 mi) orbital arc.^[21]

The ORBCOMM OG2 satellites are being manufactured by an industry team led by Sierra Nevada Corp and Argon ST, a Boeing subsidiary. A total of 18 ORBCOMM next-generation OG2 satellites were in production as of February 2013. ORBCOMM OG2 satellites will provide enhanced ORBCOMM messaging capabilities, increased capacity, and automatic identification systems (AIS) service. The agreement with SpaceX to launch 18 satellites on its Falcon 9 rockets was signed in December 2012 for a total cost of $42.6 million.^[22]

Launches

See also

• Globalstar
• Iridium Satellite LLC
• Gonets

References