20/Aug/2014 - Last News Update: 07:03

Satellites have an electric future

Category: Technology

Published: 14th Jul 2012 11:16:54

One of the most interesting trends in satellite production in the next few years is likely to be the wide introduction of electric propulsion (EP).

More and more satellites will be launched not with chemical thrusters to manoeuvre them in space but with ion propulsion units.

We've seen electric engines fitted to scientific spacecraft in recent years, but not so much on commercial satellites.

Boeing has charged out of the box on this one, agreeing to build four "all electric" telecommunications spacecraft for Asian and Mexican operators.

The attraction is mass - or rather, lack of it.

Chemical thrusters require large tanks of propellant; electric engines, while they don't provide quite the same initial boost, do not need anything like the same volumes of fuel and can work for much longer.

The downside is that it takes you longer to put a satellite in its final orbital slot; the big plus, however, is that you get a much lighter satellite.

That weight saving can either be given over to more payload (transponders in the case of telecommunications satellites), or allow the satellite to squeeze on to a smaller, cheaper rocket.

The latter strategy is the one now being looked at seriously for the future of Galileo, Europe's new satellite navigation system.

It needs 30 spacecraft in orbit to operate a full network (with spares); and because Galileo will be an on-going service, there will be an on-going requirement for replacement satellites.

Galileo, as we all know, is a hugely expensive project, costing billions of euros.

Part of that cost comes down to the price of the rockets used to get the platforms into the sky. If that could be tackled, our taxes would go further.

Currently, Galileo satellites are launched two at a time on a Russian Soyuz rocket.

It costs roughly as much to launch those two satellites as it does to build them. So, if you could get a third satellite aboard, you'd suddenly jump to a new cost regime.

This week, at the Farnborough International Airshow, the two companies making Europe's Galileo spacecraft put pen to paper on their contractual relationship.

OHB System of Bremen, Germany, and Surrey Satellite Technology Limited (SSTL) from Guildford, UK, can now turn out a Galileo satellite for about 30m euros.

That has come down from roughly 40m euros per spacecraft when they were first engaged to do the job by the European Commission and the European Space Agency.

But getting the cost down much further is really a launch issue, and electric propulsion could be the solution.

"It is feasible to take Galileo satellites up with electric propulsion, if the technology is available and mature enough," commented OHB's Ingo Engeln.

"You need more time to get the satellites in place, of course, but for the next generation this should be no problem."

And Giuliano Gatti, who works on the Galileo project for Esa, added: "It would mean you could get one satellite on Vega, three on Soyuz and up to six on the Ariane 5."

Europe has a lot of experience already in ion engines.

The concept is simple enough. Strip the electrons off a stream of xenon gas atoms so that they become charged (ions). Then put those ions in a magnetic field and accelerate them to extremely highly velocities in one direction to provide thrust for your satellite in the opposite direction.

You may be aware of Goce, the European Space Agency's gravity mapping satellite. This flies so low to make its maps that it must continually fire its ion engine to counteract the wisps of atmosphere still present at an altitude of 260km.

It was launched in 2009 with just a 40kg tank of xenon and is still working.

Of course the penalty is that ion engines put you in the slow lane.

Chemical thrusters might not burn as long, but they give you great initial acceleration and a satellite can be ejected from its rocket and be ready for use in its correct position in the sky in a matter of weeks.

With electric propulsion, it would take months.

"Where the EP variant will come into its own is in the future, once the Galileo system is in place and you have to consider replenishment, perhaps of single spacecraft," commented John John Paffett.

"At the moment, Soyuz and Ariane are quite efficient ways of populating a constellation; but what if you have a single spacecraft failure?

"It makes no sense to put an additional four or six spacecraft into an orbital plane. So the question then becomes: how cheaply can you acquire a small launch vehicle, drop a satellite off in any arbitrary orbit and have EP do the transfer from there?"

The contract signed between OHB System and SSTL brings another 80m euros' worth of work to the Guildford company.

OHB also signed a contract with Culham's ABSL at the show. The British company will be providing the batteries that go into Galileo satellites.

BBC News External Link Show Citation

Latest News

Harvard Citation

BBC News, 2012. Satellites have an electric future [Online] (Updated 14th Jul 2012)
Available at: http://www.ukwirednews.com/news/1440525/Satellites-have-an-electric-future [Accessed 20th Aug 2014]

News In Other Categories

  • Gaza conflict: Israel 'targets Hamas leader Deif'

    The wife and child of a Hamas militant leader have reportedly been killed in Israeli air strikes on Gaza which have left 11 people dead.
  • Bristol Academy extends reach overseas with first foreign students

    With the doors to its brand new £1million training centre officially open, one of the UK's leading apprentice training providers, Bristol based S&B Automotive Academy, is showcasing its world-class facilities by launching a series of foreign student exchanges for the first time in its 41-year history. To get a flavour of what life is like as an apprentice in the UK, the Academy hosted 16 apprentice engineers and bus drivers from the G9 Automotive College in Hamburg, Germany, as part of a Europe-wide vocational training initiative called the ‘Leonardo Programme’ with support from the European Social Fund. In a reciprocal arrangement, S&B will be sending nine apprentices to Germany during February 2012 so that they can get an appreciation of life in the automotive industry on the Continent. A further three German exchange groups are being planned for next year. Designed to assist the development of vocational skills and training across Europe, including work placements for trainees, the Leonardo Programme has a budget of €1.75bn, which is helping to encourage UK organisations to work with their counterparts abroad. In what is expected to be another challenging year for employers in the UK automotive sector, S&B’s Chief Executive, Jon Winter, claims that the exchange initiative will bring many benefits to the Academy and its apprentices: “In a world of global automotive brands, it’s important for our learners to understand the international context of the industry they have chosen to make their career. This new exchange programme will enable apprentices and Academy staff alike to achieve a better understanding of the challenges and opportunities within the automotive arena in Europe. With the Academy’s influence also extending to the USA and Asia, there’s every possibility that this initiative could move further afield in the future.” Continued Winter: “The need for skilled technicians across the world is on the increase and we actively encourage our apprentices to look at broader horizons during their training. Many of them have already learned the phrase ‘Vorsprung durch Gelehrtheit’, quite simply, ‘Advancement through learning.” In the 2010/11 academic year, S&B doubled the number of successful Apprenticeships over the previous year with some 350 apprentices graduating from the Academy. At the same time, achievement levels reached an all-time high with an overall success rate of 85%. For those learners on the Advanced Apprenticeship three-year programme, success rates were even higher, at over 98%. PHOTO CAPTION: As part of their exchange visit, S&B Automotive Academy arranged for the German apprentices to visit Hampshire bus operator, Bluestar, at its Barton Park depot. The students are pictured with S&B’s Andy West (3rd right) and Steve Prewett, Bluestar’s Area Engineering Manager (2nd right). Ends http://www.sandbaa.com
  • Great Britain's Kieron Achara reveals £15-a-day struggle

    Great Britain forward Kieron Achara says he and his team-mates are living on £15 a day as they try to reach the European Championships.
  • Youth mental health care 'in dark ages', says minister

    Mental health services for young people in England are "stuck in the dark ages" and "not fit for purpose", according to a government minister.
  • Japan exports growth fuels recovery hopes

    Japanese exports showed a surprise rise in July, reigniting hopes of growth for the world's third largest economy.
  • Markus Frind: The man 'behind a million babies'

    American writer and critic Susan Sontag once said: "Nothing is mysterious, no human relation. Except love."