Space blog

Exciting news today as 14 of the world’s leading space agencies revealed their agreed vision for globally co-ordinated space exploration to the Moon, Mars and beyond.

The British National Space Centre was among the 14 space agencies that developed the document. These were: ASI (Italy); BNSC (UK); CNES (France); CNSA (China); CSA (Canada); CSIRO (Australia); DLR (Germany); ESA (European Space Agency); ISRO (India); JAXA (Japan); KARI (Republic of Korea); NASA (USA); NSAU (Ukraine); and, Roscosmos (Russia).

Following months of intensive discussions, they published their common ideas for space exploration: The Global Exploration Strategy: The Framework for Co-ordination.

The document outlines the rationale for society to explore space, defines the current focus and process of space exploration, the current interest in returning to the Moon and exploring Mars, and proposes a framework for the future co-ordination of global space exploration.

Welcoming the publication of the document, Science and Innovation Minister Malcolm Wicks said:

“This document marks the start of a new era of space exploration. Since the launch of Sputnik in 1957, we have learnt much about how to explore space and have experienced the benefits of scientific discoveries in our everyday lives. Innovations such as exploiting space for global communications, weather forecasting and helping emergency services have all flowed from the first half-century of space exploration.

British National Space Centre - which co-ordinates UK civil space activities and represents the UK at the European Space Agency - was fully involved in shaping this document. Following its publication, it is expected that a voluntary, non-binding forum (the International Co-ordination Mechanism) will now be established so that all 14 nations can share their plans for space exploration, and collaborate to strengthen both individual projects and the collective effort.

Mr Wicks also highlighted the benefits of space exploration to the economy.

“During this century we are sure to see some fantastic voyages of discovery as robots and humans venture further into our Solar System. What they learn will excite and inspire new generations to get involved in science and create new technology that could benefit the whole economy."

Read the BNSC press release.

The ESA-supported Surrey Rigid Array (SRA) development project at SSTL completed its Manufacturing Kick-Off Review at Airborne Composites in Holland on 15th May. The review followed on from a successful Critical Design Review (CDR) with ESA in February and marked the initiation of the manufacture of the full size solar array panels. Upon completion of the panel manufacture and acceptance testing, the panels will be ready for solar cell lay-down and the subsequent environmental test campaign.

The Surrey Rigid Array is precisely engineered for high energy output, and crucially, low weight. The carbon fibre / aluminium sandwich panels are produced in a clean room environment and cured in the Airborne autoclave at the Ypenburg, The Hague facility.

SRA is partially funded by ESA’s Advanced Research in TElecommunications Systems funding stream 4 (ARTES 4) initiative aimed at supporting developments within industry that are close to market. The project addresses the design, analysis, manufacture and test of a solar array suitable for small Geostationary (GEO) satellite platforms with a 7 year mission lifetime requiring 1kW minimum power generation.

Earlier this week, the SSTL built GIOVE-A satellite successfully transmitted its first navigation message, containing the information needed by user receivers to calculate their position. Prior to reaching this milestone, the satellite had been broadcasting only the data needed for measuring the receiver-to-satellite distance.

The first Galileo navigation message was created by the navigation signal generator unit on board GIOVE-A, using content prepared by the GIOVE Mission Segment. This week-one navigation message was uplinked to GIOVE-A on 2 May from the Guildford ground station operated by Surrey Satellite Technology Ltd (United Kingdom) and then transmitted from the spacecraft to the users. The objective of the test was to demonstrate an end-to-end link between the Mission Segment and the user receivers. The navigation message is being generated for demonstration purposes only – no service guarantee is provided.

The complete radio transmission from GIOVE-A carries a navigation signal and a navigation message. The navigation signal contains the information needed to accurately measure the distance from the satellite to the user receiver. The navigation message provides the timing and spacecraft orbit data needed to calculate the time and exact position of the satellite. One of the main tasks of the GIOVE Mission Segment is the generation of this navigation message.

GIOVE Mission Segment

The GIOVE Mission Segment comprises two main elements, a world-wide network of 13 Galileo experimental sensor stations and the GIOVE Processing Centre (GPC) located at ESA’s European Space Research and Technology Centre (ESTEC) in Noordwijk, The Netherlands.

Note: The GPC is operated by European Satellite Navigation Industries (ESNIS) – the new name for Galileo Industries.

In order to generate the navigation message, the sensor stations track the signal-in-space from GIOVE-A and send the tracking information to the processing centre. The GPC computes, among other things, the precise satellite flight path and on-board clock model. It then generates a prediction of the orbital path and clock performance for the near-term future, which is the basis of the navigation message. Next, this message is transmitted to GIOVE-A which retransmits it to the user.

Aside from navigation message generation, the primary tasks of the GIOVE Mission Segment are performance characterisation of the on-board clocks, orbit modelling, and operations planning & telemetry analysis for the navigation payload.

Another validation step completed

On 12 January 2006, GIOVE A transmitted the first Galileo signals, thereby securing the frequencies allocated to Galileo by the International Telecommunication Union. Now, the transmissions are carrying a navigation message – this means that the satellite is providing information that is needed by a receiver to calculate its position.

Although the navigation message structure of GIOVE-A is slightly different, the GIOVE-A navigation transmissions are fully representative of those that will be sent by the operational Galileo system. The operating principles are identical and the achievement of the first navigation message is another important step in the validation of the Galileo system design.

GPS interoperability

Following this successful test, in the near future GIOVE-A will begin to continuously broadcast the navigation message, with the message content being updated whenever the satellite is visible from the Guildford uplink station. Additionally, the message content will be extended to include the time offset between GPS and the experimental Galileo system. Knowing this offset, the Experimental Galileo-GPS Time Offset (E-GGTO), will allow the user to build a position fix using GPS satellites and GIOVE-A.

Galileo is a joint initiative between ESA and the European Commission. When fully deployed in the early years of the next decade, it will be the first civilian positioning system to offer global coverage.

ESA press release: GIOVE-A transmits first navigation message

What next?

SSTL were awarded a second contract on March 5th 2007 for initial activities leading to the construction of a second spacecraft for the Galileo satellite navigation system. Named GIOVE-A2, the new satellite (estimated total value 25 to 30 million Euros) will be based on the company’s proven GIOVE-A technology. From now on, there will always be a European navigation satellite in space.

ESA press release: GIOVE-A2 to secure the Galileo programme