Following weeks of rigorous launch preparations, both NigeriaSat-2 and NigeriaSat-X satellites took off at 7:12 GMT on 17th August and are now in orbit and acquiring their first imagery. We’re looking into how it all went and what’s happening next.

Days before launch all seven satellites sharing the launch were integrated and the space head module assembled. The assembly was then rolled out to the rocket silo where Russian Strategic Missile Forces were waiting for the final silo operations. Besides the mission launch team, a group from SSTL and Nigerian delegates, including SSTL Executive Chairman, Sir Martin Sweeting and NASRDA head, Dr S.O Mohammed, were onsite in Yasny for the launch. This video shows the take off from the Yasny launch base.

The launch went according to plan, and after the separation from the launch vehicle was confirmed, ground stations in Abuja and Guildford established contact with NigeriaSat-2 and NigeriaSat-X respectively. This fantastic animation shows the launch sequence, and how the satellites are detached in the correct order for their intended orbits.

Continue reading "NigeriaSat-2 and NigeriaSat-X orbiting Earth"

As the launch of NigeriaSat-2 and NigeriaSat-X grows ever closer, the final preparations are underway at the launch site in Yasny, Russia. What does it actually mean to get a satellite ready for take-off? We’ve spoken to Project Manager Andrew Carrel about the work of the mission launch team, who are busy onsite getting the satellites ready to be shot up in space.

Once unpacked from their transit case the mission launch team, consisting of engineers from SSTL and Nigeria’s NASRDA, immediately began a series of meticulous tests to make sure that the satellites had made the journey in good condition and that everything was working as it should. With no problems discovered, the team could then move on to making the final preparations and fittings.

Andrew Carrel said: “When transporting satellites such a long distance, there’s always a risk things will have changed since the tests we made at SSTL before we pack them up. We were pleased to see that everything was working absolutely fine, making the preparation work much more straightforward.”

The campaign team repeated the tests done at SSTL in the final AIT stage, testing the electrical circuits and making sure that, for example, the solar panels reacted correctly when illuminated. The satellite’s subsystems were then prepared, carefully filling up the propellant and charging the batteries in the power system. Many of these preparations can only be made in the last few days before the launch to make sure the satellite is in optimum condition. This includes removing the so called “red tag” items, such as lens caps and other protective covers, as well as fitting the so called “green tag” items, such as electrical plugs to replace tests cables.

Continue reading "Rigging NigeriaSat-2 for launch"

The European Space Agency (ESA) Proba-2 mission has entered its 2 month commissioning period following a successful launch. SSTL’s Microsatellite Gas Propulsion System is on-board the 137kg small satellite and was integrated by the satellite’s manufacturer Verhaert Space Systems.

The Microsatellite Gas Propulsion System is based upon SSTL’s heritage xenon resistojet propulsion system. Its highly cost effective design provides an enhancement over conventional cold gas propulsion.

By using the resistojet thruster to heat the exhaust gas to over 300ºC a 30% increase in efficiency is gained. The electronically controlled pressure regulation improves thrust control compared to conventional mechanically regulated propulsion systems for greater positioning control in orbit.

The warm gas propulsion system is simpler, safer and cleaner than chemical propulsion systems. This makes them ideal for launcher injection correction, constellation station keeping and acquisition and orbit height maintenance for small, low cost spacecraft.

Proba-2 is the follow-on to the highly successful Proba-1 satellite launched in 2001 that carried the Compact High Resolution Imaging Sensor (CHRIS) payload manufactured by SSTL’s Optical Payloads Group. Proba-2 will demonstrate 17 advanced satellite technologies – such as miniaturised sensors for ESA's future space probes and a highly sophisticated CCD camera with a wide angle view of about 120 degrees – while carrying a set of four science instruments to observe the Sun and study the plasma environment in orbit.

A datasheet for the SSTL Microsatellite Gas Propulsion System is available on the SSTL Website.

SSTL’s UK-DMC2 satellite has successfully completed pre-launch tests and is integrated with a Dnepr launch vehicle at the Baikonur Cosmodrome in readiness for launch on Wednesday, 29th July 2009 at 18:46 UTC, 19:46 BST.

The new satellite will be operated by subsidiary company DMCii to provide an enhanced imaging capability and operational service to the Disaster Monitoring Constellation (DMC). UK-DMC2 has a number of enhancements over previous DMC spacecraft contributing to SSTL’s continuing evolutionary design approach.

UK-DMC2 carries a higher resolution optical payload which will provide 22m ground sample distance (GSD) images, compared with 32m GSD on the four operational satellites currently in the constellation. The 22m imagery has twice the data density of the 32m imagery without loss of Signal to Noise Ratio (SNR) and maintains the ultra-wide 600+km swath.

The satellite carries two high-speed X-band transmitters that will both operate at 20Mbps or 80Mbps. This will enable the satellite to download images up to 10 times faster than previous DMC spacecraft. Storage capacity has increased from 1 to 1.5 GByte on the first generation of DMC spacecraft up to 12 GByte on UK-DMC2. These advancements, in combination with improved power generation and storage systems, will allow UK-DMC2 to rapidly map large areas such as Europe or other continents.

The advances in data throughput and power generation have enabled two new operational modes. Firstly, a near-real time imaging and downlink mode allows imagery acquired within a ~2000 km radius of a ground station to be downlinked within the same pass and, secondly, the implementation of a broadcast downlink mode that enables customers with a receive-only ground station to receive data directly from UK-DMC2.

These technology improvements not only make the satellite more flexible than previous designs, but also dramatically increase the operational imaging capacity by allowing the satellite to store and download much larger volumes of multi-spectral image data.

In practical terms, the increased imaging capacity means that the satellite has less “dead time”. By fully using the different modes available, this latest DMC satellite will be able to rapidly download significantly more image data than previously possible. The satellite does not need to wait until it has emptied the onboard storage before being re-tasked to acquire further images elsewhere.

As an example, DMCii annually provides coverage of the Amazon Basin. These coverage campaigns have taken 6 weeks to complete with two of the current DMC spacecraft. By comparison, UK-DMC2 on its own can cover the same area in just 11 days.

The 96kg UK-DMC2 satellite is based upon SSTL’s SSTL-100 small satellite platform, which uses solar cells integrated into the spacecraft’s surface to generate power. UK-DMC2 includes an additional deployable solar panel that will increase power generation by approximately 50%.