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Talking and looking: Iridium's 'next' big idea

Jonathan Amos | 11:40 UK time, Wednesday, 25 August 2010

Their job is to provide communications anytime, anywhere. And it's been a busy summer for the companies that provide satellite phone and data services.

Earlier this month, we saw to launch three huge broadband satellites. The US Globalstar concern was also making news, taking .

More on both these developments in future postings, but I want to just dwell for a moment on that other big mobile satellite services story of the summer - .

Virginia-based Iridium, like Globastar, is having to upgrade its current network and has contracted Franco-Italian manufacturer Thales Alenia Space to build 81 spacecraft for the purpose.

Sixty-six satellites will be put in six planes some 780km above the Earth (the remainder will be held on the ground as spares) over the course of 2015-2017.

It's an enormous - and expensive - undertaking that I first wrote about in June.

What I didn't touch on at the time was the piggy-back element of Iridium Next - the new constellation's "hosted payloads".

Iridium Next satellite

On every one of the new spacecraft, Iridium is making available a 30-by-40-by-70cm volume that can be filled with a third-party's Earth or space observation sensor, up to a mass of 50kg.

Iridium likes to describe its Next project as the biggest private space venture in the world today. Certainly, if a lot of these hosted payload opportunities are taken up then Next would also become the largest privately operated Earth observation programme as well.

It's not a new idea that telecommunications satellites should also engage in a bit of Earth sensing on the side, but it's the scale of what's on offer here which is fascinating.

Several studies have been done, some involving major space agencies, to look at how you might employ the new Iridium constellation in an Earth observation role. Ideas include:

  • GPS radio occultation - sensing the way GPS signals bend through the atmosphere to learn something about temperature and humidity
  • Ocean and land colour imaging - looking for changes in ocean health and land use, eg algal blooms and deforestation
  • Earth's radiation budget - measuring the balance between the incoming energy from the Sun and outgoing energy leaving the Earth
  • Space situational awareness - making a catalogue of objects in space, some of which might pose a

    Those I've spoken to say Iridium's chief selling point would be its ability to allow users to run networks of sensors across its constellation, enabling frequent measurements to be taken at many locations at different times of the day. In other words, to have a persistent surveillance capability.

    That clearly has military connotations - it could allow commanders to have instant space imagery because there would always be an iridium satellite overhead (that's the nature of the Iridium system).

    But also from a scientific perspective, multiple sensors would allow you to sample phenomena that evolve rapidly through a day or look very different in day and night conditions. Monitoring city pollution is perhaps a good example.

    Artist's impression of an Iridium Next satelliteThe US National Science Foundation has funded a Johns Hopkins University project called , which will use the data from magnetic field sensors already flying on the existing Iridium network to study the space environment around Earth.

    Again, persistent sensing of fast-changing circumstances.

    It will be interesting to see how many of the hosted payload opportunities are taken up. Some of the big agencies like the European Space Agency (Esa) have already said the proposition is not for them. That's not surprising - Esa likes to work on its own cutting edge projects; it's not so interested in taking part in operational systems.

    Price will be a key issue, too. Iridium is quoting something on the order of $5-9m to get onboard a satellite, with a $100,000-500,000 annual service charge depending on data needs.

    It's certainly competitive, but again some organisations, especially if they have limited observation needs, might prefer to go down the route of buying a single small satellite which can provide high data rates they don't have to share with anyone else.

    And time is clearly a factor. Iridium and Thales Alenia will be locking down the design of the new spacecraft towards the end of 2012. That's not long for someone to get an instrument ship-shape

    Speaking to Don Thoma of Iridium, he believes at least two-thirds of the Next satellites will fly with an additional payload. No deals have been signed yet but he expects that to change now that the company has chosen Thales Alenia to build the satellites:

    "What that has done for us is give us one design. Before that we had a generic hosted payload interface and a generic satellite bus that we could talk about to potential customers. And the biggest question we were getting was, 'OK, when are you going to make your selection and when are you moving forward with the prime contract?' Now that's done - the satellite bus is chosen, the actual hosted payload interfaces are clearly defined - and frankly it starts the clock to a set of critical development milestones over the next two years that really define the activities that have to occur to make the first launch."

    One to watch.

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