UK- DMC- 1, one of the first generation Disaster Monitoring Constellation satellites, is to be retired from service after over 8 years in orbit. UK-DMC-1, was launched on 27th September 2003 with fellow Constellation satellites NigeriaSat-1 and BILSAT-1 from the Plesetsk Cosmodrome on board a Kosmos 3-M rocket. It has exceeded its original 5-year design lifetime by over 50% with an impressive 8 years and 1 month of operation. UK-DMC-1’s imaging workload has now passed to UK-DMC2 and the new generation of DMC satellites, providing data continuity for DMCii’s customers.

UK-DMC-1 was part of the first-ever microsatellite Earth Observation constellation, which introduced remarkable EO abilities for both national and international benefit. The constellation is the work of a pioneering international co-operation consortium led by SSTL and made up of six countries: Algeria, China, Nigeria, Turkey, Spain and the United Kingdom.



In addition to UK-DMC-1’s remote sensing capability, the SSTL100 based satellite also carried several experimental payloads that have proved groundbreaking in themselves. The Cisco router in Low Earth Orbit (CLEO) was a joint project between NASA Glenn Research Center, SSTL and Cisco Systems. It tested delay-tolerant networking in space and led the way for developments towards an interplanetary Internet system.

The GPS Reflectometry experiment on UK-DMC-1 was the first dedicated experiment to demonstrate the viability of using reflected GPS signals from space to measure geophysical parameters, such as ocean weather. For the first time, spaceborne signals were received by the satellite from reflections off sea, ice, snow and land and a follow-on instrument will be flying on TechDemoSat-1. UK-DMC-1’s Resistojet technology was also the first of its kind. This water-based propulsion system proved to be both an efficient and low cost alternative to the use of hazardous propellants which require infrastructure and can cause complications at high pressures.

UK-DMC-1 retired gracefully; like all recent SSTL missions it was prepared for its ‘End of Mission’ as a precautionary measure to minimize space debris. This process began in September 2010 and involved using up its remaining propellant to passivate the satellite, and also lowering the orbit to reduce its remaining time in space before burning up in the Earth’s atmosphere. When this work was completed the satellite continued to be fully operational, continuing to relay image data down to SSTL’s groundstation.

Why retire now? Well, the satellite’s battery ages over the mission lifetime and has now reached a point, well beyond its original mission design life, where it is unable to provide enough power to support full payload operations. With this in mind, the SSTL Spacecraft Operations Team have suspended the UK-DMC-1 workload, and the satellite is now only monitored periodically from SSTL Mission Control in Guildford.

A group of students from Royal Grammar School, Guildford is exploring the possibilities of a scientific phenomenon to evaluate its potential for propelling a Tumbleweed Rover through the hills and valleys of Martian terrain.

The project is SSTL’s contribution to this year’s Engineering Education Scheme. EES is an annual event run by The Engineering Development Trust, the largest provider of STEM (science, technology, engineering and mathematics) enrichment activities for British young people. The EES links teams of Year 12 pupils with local companies to provide students with first-hand experience in science, engineering and technology that will enable them to make informed decisions about their future.

This isn’t the first time SSTL has sponsored the scheme. Two years ago SSTL supported a team from Farnborough college on a study to "Investigate possible ways of detecting earthquake precursor signals using satellites, to help us move from disaster monitoring to disaster mitigation". The constructive results of the study have been fed into the Mission Concepts team that evaluates new ideas in the innovation underbelly of SSTL.

This year, Sahand Ghanoun from the Flight Software Team is mentoring four students from Royal Grammar School, Guildford to study a "Low cost propulsion system utilising the Crookes radiometer effect". Their study will look into the possibility of using the Crookes radiometer effect as a supplementary source of propulsion for the NASA Tumbleweed Rover.

The spherical Tumbleweed Rovers could be used to explore the valleys of Mars that wheeled probes are unable to reach, relying on the Martian wind to move them around, see this video. SSTL’s Mission Concepts would like to know if the Crookes radiometer effect could provide an alternative means of propulsion when the Martian wind is insufficient to move the Rovers.


The Crookes Radiometer Effect can be observed when metal vanes in a partial vacuum (like the Martian atmosphere) move when exposed to light. The vanes are painted white on one side and black on the other. When exposed to light or infrared radiation the vanes move because the black side of the vane becomes hotter than the white and transfers more heat energy (and therefore, kinetic energy) to the air molecules behind the vane resulting in a new torque in that direction. In addition, another force is exerted by the flow of the gas molecules from the cooler side to the hotter side in an effect known as thermal transpiration.

A combination of wind power and the photo-thermally induced principle on which the Crookes radiometer works would cost less than solar panel powered propulsion and might make the tumbleweed rover concept viable in a shorter timeframe.

The project kicked off on Friday, 4th November, when Sahand presented to the four RGS students and their teachers and gave them a tour of SSTL facilities. The programme will run until April 2012 when the team will show off their work and a report to a team of assessors.

DMCii has acquired images of flooding in both El Salvador and Ghana - just two of the many floods that have taken place recently worldwide.

El Salvador in South America was hit by a tropical depression at the end of October. Torrential rains resulted in rockslides, landslides and widespread destruction of crops and homes. Water levels rose by a reported 3m and it is said that up 10% of the country was flooded. The aftermath of this extreme weather can be seen in this image taken by UK-DMC-2 on the 21st October.

Accra in Ghana also experienced heavy rains that started on the 25th October. The nation’s capital is a low-lying area and prone to flooding. However it is unusual in October as the rainy season is June to August in Ghana. The flooding has led to sanitation fears and massive disruption of transport links.


If you’re interested in seeing more remarkable images from UK-DMC-2 please visit DMCii’s photostream on Flickr. All images are acquired by UK-DMC-2 © DMCii, 2011. All rights reserved

A Channel 4 news report on Sunday 9th October 2011 covered SSTL’s work towards the creation of an Interplanetary Internet (IPN) system that could change the way space exploration is conducted.

The development of the Internet originally aimed to connect the world, now one of its founders, Vint Cerf (Google Chief Internet Evangelist) is pioneering something much bigger: a network whose reach could extend further than our solar system and potentially allow transfer of data to and from spacecraft travelling to stars 30 trillion miles, or 4 light years, away.

Our terrestrial Internet requires few resends between nodes and data can be quickly resent end-to-end. This works well on Earth where everyone is significantly less than a light second apart and where a constant connection can be provided. However, the bigger the distances involved in space travel, the longer the data takes and the harder it is to guarantee a connection as it can be blocked by the sun and planets. This means that there can be delays of hours, or even days in the transfer of data.

The use of delay tolerant networking rectifies this. Under this system, each node stores data until it can be forwarded to the next node allowing greater use of available contact periods, greater accuracy in the transfer of data, and shorter overall delays in data delivery.

In SSTL’s current work, delay tolerant networking could be used to ensure maximum contact between Low Earth Orbit (LEO) satellites and Earth. In constellations of satellites, each individual acts as a node, and can communicate with each other using Inter-Satellite Links (ISLs) to send data via the quickest route. Data might be sent to a geostationary satellite that has contact with a ground station, providing more opportunities to get data downlinked. This system is faster and much more cost effective if cost is considered as data per pound or euro - it’s more science for your money. Also, the network can be fully automated, reducing operation costs.

Using delay tolerant networking to send and receive data reliably, and as soon as possible, could be particularly useful for defence and disaster monitoring, by reducing the delay between the satellite acquiring data and then waiting for its orbit to bring it within contact with its groundstation so that the data can be downlinked.

In 2003, CLEO, a Cisco router on a LEO satellite was launched onboard SSTL’s UK–DMC-1 satellite and is still in use after eight years in orbit. Working together and using Internet technology to prototype the future Interplanetary Internet, NASA Glenn Research Center, SSTL and Cisco Systems were the first to evaluate the delay-tolerant networking bundle protocol in space. CLEO was a prototype for the concept of IPN, and was followed by the launch of Intelsat’s IRIS geostationary satellite in 2009.

Despite discussions as early as 1998, IPN is only now becoming a reality. A prototype node is already on the International Space Station and an interplanetary Internet system could potentially be in operation for interplanetary exploration by 2018/2020.