Orbcomm - Satellites

Satellites

The current-generation satellites each weigh 42 kg (93 lb). Two disc-shaped solar panels articulate in 1-axis to track the sun and provide 160 watts of power. Communication with subscriber units is done using SDPSK modulation at 4800 bit/s for the downlink and 2400 bit/s for the uplink.

Each satellite has a 56 kbit/s backhaul that utilises the popular TDMA multiplexing scheme and QPSK modulation. Orbcomm is the only current satellite licensee operating in the 137-150 MHz VHF band, which was allocated globally for "Little LEO" systems. Several such systems were planned in the early to mid 1990's but Orbcomm was the only one to successfully launch. In the continental US, ORBCOMM statistically relays 90% of the text messages within 6 minutes, but gaps between satellites can result in message delivery times of 15 minutes or more. Orbcomm reported during an earnings report call in early 2007 that 50% of subscriber-initiated reports (messages of six bytes in size) were received in less than 1 minute, 90% in less than 4 minutes and 98% in less than 15 minutes. With the current constellation of ORBCOMM satellites, there is likely to be a satellite within range of almost any spot on Earth at any time of the day or night. Every satellite has an on-board GPS receiver for positioning. Typical data payloads are 6 bytes to 30 bytes, adequate for sending GPS position data or simple sensor readings.

A total of 35 satellites were launched by ORBCOMM Global in the mid to late 1990s. Of the original 35, a total of 29 remain operational today, according to company filings. The plane F polar satellite, one of the original prototype first generation satellites launched in 1995, was retired in April 2007 due to intermittent service. Two additional satellites (one from each of Plane B and Plane D) were retired in 2008 also due to intermittent service. The other five satellites that are not operational experienced failures earlier. The absence of these eight satellites can increase system latency and decrease overall capacity. Orbcomm has invested in replacement satellites as the first generation is at or nearing end of life. On 19 June 2008 six additional ORBCOMM satellites were launched with the Cosmos-3M rocket: one ORBCOMM CDS weighing 80 kg, and five ORBCOMM Quick Launches weighing 115 kg each. These new satellites were built by German OHB System AG (platform) and by Orbital Sciences Corp. (payload) and included a secondary AIS. Design and production of the satellite platform was subcontracted by OHB System to Russian KB Polyot. On November 9, 2009 ORBCOMM filed a report to the United States Securities and Exchange Commission stating that since launch, communications capability for three of the quick-launch satellites and the CDS has been lost. The failed satellites experienced attitude control system anomalies as well as anomalies with its power systems, which resulted in the satellites not pointing towards the sun and the earth as expected and as a consequence have reduced power generation. The company has filed a $50 million claim with its insurers covering the loss of all six satellites and received $44.5 million in compensation.

On 3 September 2009 a deal was announced between ORBCOMM and Space Exploration Technologies (SpaceX) to launch 18 second-generation satellites with SpaceX launch vehicles between 2010 and 2014. SpaceX originally planned to use Falcon 1e rocket, but on March 14, 2011 it was announced that SpaceX will use Falcon 9 to carry the first two ORBCOMM next-generation OG2 satellites to orbit in 2011. On Oct. 7, 2012, the first SpaceX Falcon 9 launch of a prototype OG2 ORBCOMM communications satellite from Cape Canaveral failed to achieve proper orbit and the company filed a $10 million claim with its insurers. The ORBCOMM satellite was declared a total loss and burned up in the atmosphere upon rentry on Oct. 10, 2012.