SpaceX made a fourth – and successful – attempt to launch its Falcon 9 v1.1 – tasked with orbiting six OG2 satellites for Orbcomm’s second generation constellation – on Monday. The latest attempt – from Space Launch Complex 40 (SLC-40) at Cape Canaveral – launched at 11:15 am local time, following a slight delay due to Ground Support Equipment (GSE) issue.
Falcon 9 v1.1 Mission:
As a result the satellite was left in an unusable orbit from which it quickly decayed, unable to fulfil its mission. This anomaly, overall a partial failure, remains the only blemish on the Falcon 9’s launch record.
Eighteen Orbcomm Generation 2 (OG2) satellites have been produced; of these one was lost in the 2012 failure, six are aboard this launch, with the remaining eleven expected to fly together aboard a single Falcon 9 later this year.
Orbcomm has options for up to thirty more satellites which can be produced for replenishment or to increase the size of the constellation should it be necessary.
The prime contractor for the program is the Sierra Nevada Corporation, with Argon ST of Virginia producing their communications subsystems.
Each spacecraft is based on Sierra Nevada’s SN-100A bus, with a mass of 172 kilograms (380 lb) and is designed for an operational lifespan of at least five years. The spacecraft are each powered by a gallium-arsenide solar panel producing 400 watts of electrical power.
Each OG2 spacecraft is three-axis stabilised with hydrazine thrusters used for attitude control.
The satellites’ communications systems offer transfer rates up to four megabits per second at VHF frequencies between 137 and 153 megahertz, with each vehicle also carrying an Automatic Identification System (AIS) receiver to pick up identification and tracking signals broadcast by ships at sea – Orbcomm intends to sell this data to coastguard services.
The second-generation constellation is expected to increase the capacity of the Orbcomm network six to twelve times over.
Not including this launch, forty seven Orbcomm spacecraft have been launched to date, with the first being the Orbcomm-X spacecraft which was deployed by an Ariane 4 in July 1991.
A technology demonstrator for the remainder of the constellation, no signals from the spacecraft were ever received. Two further demonstration launches occurred in 1993, followed by the first two operational satellites in April 1995.
The majority of the first-generation satellites were deployed in cluster launches which made use of Orbital Sciences’ Pegasus-XL rocket.
The original satellites were designed to operate for four years, however it was not until 2008 that a replenishment launch took place, with a Russian Kosmos-3M carrying five Orbcomm Quick Launch satellites and the CDS-3 technology demonstrator.
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