Riding the strangest rocket in the world
It's a curious beast, there's no doubt about that.
The Dnepr rocket that will carry Europe's ice explorer Cryosat into orbit next month is quite unlike most satellite launch systems.
But then most satellite launchers did not start out as nuclear missiles.
The Dnepr is one of those "swords into ploughshares" stories.
Under the terms of the Strategic Arms Reduction Treaty, a number of former Soviet SS18 ICBMs were decommissioned. Their atomic warheads were removed and their third-stages were modified to deploy spacecraft.
More than 40 satellites have now ridden the Dnepr into orbit. They launch from the famous Baikonur cosmodrome in Kazakhstan, and from the Dombarovsky base just across the border in southern Russia.
The company that markets the vehicle, ISC Kosmotras, has charged the European Space Agency (Esa) a little under 20m euros to send Cryosat on its way.
I've attached a schematic to this posting to illustrate how the Dnepr launches.
It may seem a little bizarre, but the methodology is all driven by its nuclear heritage.
Essentially, the rocket is packed inside a canister which is loaded into a silo.
At launch, a black powder charge underneath the vehicle produces rapidly expanding gases that pop the Dnepr up out of the ground like a champagne cork.
There is then this heart-stopping moment when the vehicle just hangs 20m above the ground before the first-stage motors kick in and the former war machine climbs skyward.
You can see a youtube video of Dnepr launches here.
For Cryosat, the Dnepr is going up from Baikonur. It will fly south. Its first-stage will fall to Earth in Turkmenistan, another former Soviet republic. The second-stage will fall into the Indian Ocean.
It's then that something quite unusual will happen. When satellites are deployed by upper-stages, the normal practice is to use a spring mechanism to push them out in a forward direction.
The Dnepr is completely different. Immediately after the second and third-stages separate, the third-stage does a flip manoeuvre; and it flies backwards!
An artist's impression of Cryosat's rearward ejection from the Dnepr third-stage
A shroud that covers the satellite and protects it from the exhaust gases of those flipping thrusters is then jettisoned. It's at this point that the satellite is ejected. It gets chucked out the back, in the rearward direction.
Why? Well, Soviet engineers found this to be a highly accurate way to target nuclear warheads! Let's hope it works for Cryosat, too.
In getting the satellite into an orbit 720km above the Earth, the vehicle will be working at the limit of its performance. As you know, this Cryosat spacecraft is a rebuild of the mission that was lost on launch in 2005.
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It will mean Cryosat has been deployed and picked up by its first tracking station.
Cryosat itself has had an "interesting" build up to launch.
One key moment during final testing at Baikonur occurred when it was discovered that a broken ferrite fragment had stuck itself deep inside the spacecraft's transmitter equipment.
Had Cryosat flown with this debris in place, it would not have been able to send its precious ice mapping data to Earth.
You can listen to the extraordinary story of how the fragment was retrieved by clicking on the audio featuring Esa's Cryosat project manager Richard Francis.
It's quite a tale and involves a surgeon from a local Kazakh hospital with a bronchoscope, and some inventive engineers with a magnet on the end of a stick.
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I'm pleased to report, though, that Cryosat is good to go. Thursday 8 April at 1357 GMT (1457 BST; 1557 CEST).
Watch this space.
I’m 
~RS~q~RS~~RS~z~RS~43~RS~)
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I don't get this part:
"But then most satellite launchers did not start out as nuclear missiles"
Most of them *did*. Titan, Atlas, Delta, Soyuz, Long March, Tsyklon ... the list is endless. Whether direct modifications or evolutions from ICBM heritage, the expendable launch industry owes much to nuclear ballistic missiles.
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I'm not sure this is a total novelty - didn't NASA use refurbished Atlas missiles as launchers? They didn't launch from silos, though!
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@neuro
Most launchers are based on ICBM technology (or were built to try out new ICBM technologies). The Dnepr, however, was an actual nuclear missile; as explained above its silo-based launch technology and warhead-based deployment technology are the same.
There are certainly many, many examples of ICBM designs which have been modified for use as launchers; there are almost certainly examples of individual launchers which have been repurposed as launchers by replacing their final stages with dedicated orbital launch stages and setting their first stages up for launchpad deployment.
But it is certainly unusual to have, essentially, an ICBM repurposed by doing little more than replacing the warheads with a satellite payload. The point is that every stage of this particular rocket was built as a nuclear missile.
Keeping that in mind the statement "most satellite launchers did not start out as nuclear missiles" is entirely accurate; the use of the term "satellite launcher" here refers to an individual vehicle, not a design.
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@Nick Simon; @neuro. No, it's not a total novelty, hence the use of the word "most". Let’s be clear. The lineage of all launchers extends back to missile tech. The point I'm making here is that these vehicles have been taken direct from nuclear duty and re-assigned. That is not true of all satellite launchers today.
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What is interesting in this case is that while other missiles based on military applications were modified to suit civilian applications, here we have rather the opposite, i.e. the civilian application being modified to suit the military basis - in fact the missile is used rather raw.
I find it an amazing way to make profit of all that rendundant stock and it certainly gives time Russia to think better of its future designs in relation to its strategic choices and thus avoid a 2-steps forward 2-steps backwards that US finally did with Ares.
For us Europeans it is a nice chance to exploit the case and organise some substantially cheaper missions (do not know details but I guess it is much cheaper that way than develop and produce new missiles...).
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Excellent article again thanks Jonathan. Your interesting updates are regular reading for me. Let's hope we start investing more into Space UK then you can report even more!
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We (the UK) were offered airlaunch Ex US balistic missiles in 1998/9 almost at no cost because we were the only firendly country with a plane that could be modified to launch them (the valcan). The offer was to use the millsies for a cheep civilian sat launche platform.
There was even a client willing to pay 50million per launch and book several hundred launches over a 5 year period, costings showed that keeping 8 valcans flying and doing the modifications and doing 1 launch a week would have netted a 35million pound profit on each launch.
The preposal was turned down by a certian chancoler as there was no mechasimum for the MOD to make a profit!
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With resources and motivation amazing things can be done. Now if some of that could transfer over to environmental issues and alternative energies we may have more positive results. My guess is the military has a vested interest in alternative fuels and this will be the foundations for development. Recycing on a grand scale with the missles..waste not...want not. Luckily the Russians had financial issues and had to become creative.
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Very interesting article. Only problem is that I was seeing creosote instead of Cryosat and I'm definitely not dyslexic.
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Great article! I loved the last part about the repair of Cryosat. These russians are amazing, they can find you anything you need, even in the middle of nowhere, be it a thermal camera, an endoscope or a bronchoscope, as long as you respect their right for a cigarette break though...
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Frankly, I am very worried rapid progress of development of missiles designed to eventually send bombs, the global situation is getting worse and got to almost always have a permanent fear of war in the Middle East or Russia or Korea.
I wish you could hear on any missile intended for peaceful purposes, the world we are let's just I do not think we get a moment to have a missile which will show a satellite for peaceful purposes.
Anyway always good to hope.
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The Dnepr is going up from Baikonur. It will fly south. Its first-stage will fall to Earth in Turkmenistan, another former Soviet republic. The second-stage will fall into the Indian Ocean. Nice post
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Great article! I loved the last part about the repair of Cryosat. These russians are amazing, they can find you anything you need, even in the middle of nowhere, be it a thermal camera, an endoscope or a bronchoscope, as long as you respect their right for a cigarette break though...
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I like the stuff from stars and to read this article was really interesting.
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I'm not sure this is a total novelty - didn't NASA use refurbished Atlas missiles as launchers? They didn't launch from silos, though!!!!
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Kelly, what is the meaning of 'dyslexic', I've never heard this term..?
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