FARNBOROUGH: Comet's tail is big story of ESA's year

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Comets probably aren’t the bad luck omens or even harbingers of doom that many early civilisations assumed – but, just to be sure, a very close eye is being kept on the snappily-named 67P/Churyumov-Gerasimenko as it hurtles towards the Sun.

Indeed, as much of the aerospace industry has its attention focused on the very important happenings at a place called Farnborough in Hampshire, it can be assumed that a crew at the European Space Operations Centre (ESOC) in Darmstadt, Germany will be paying no heed whatsoever to some air show or other. Rather, they will be anxiously tracking the progress of a small spacecraft – about the size of a hatchback car – as it closes in on Churyumov-Gerasimenko.

So far, the Rosetta mission, named after the hieroglyphics-to-Greek translation stone in London's British Museum, has been a more or less perfect affair, even after a 10-year, 6 billion km journey involving five trips around the Sun and three slingshot fly-bys of Earth – and a fourth, of Mars. But arguably the highlight of the European Space Agency’s year came on 20 January, when Rosetta “woke up” after 31 months in deep-space hibernation, during which time all its systems were turned off to save power. As ESOC’s head of mission operations, Paolo Ferri, told a Royal Aeronautical Society audience last month, he thought the hibernation part of the mission plan was “crazy” when it was proposed, but it really was the only way to manage a spacecraft cruising more than 800 million km (500 million miles) from Earth whose sole power source is a 64m² array of solar panels.

The cheers at ESOC must have woken the town of Darmstadt, if not Rosetta herself, when the spacecraft’s “alarm clock” woke it up and the machine came back to life, automatically switching on its systems, tracking stars to regain its orientation, and sending a signal home.

But since then, when Rosetta was more than 9 million km from its target, it has been closing in at a rate of around 800m/s. So, early next month, the gap will come down to about 100km. Then, Ferri’s team at ESOC will start commanding Rosetta to take a series of hyperbolic passes, to assess the comet’s gravity in anticipation of coming into a 10km “orbit” – if it is possible to fly Keppler orbits around a block of dust some 4-5km across, about the size of Mt Blanc – and, ultimately, getting as close as 2.4km to deliver a small lander, named Philae (after the Egyptian temple whose obelisk, now in London, provided further clues to decipher hieroglyphic writing).

Philae’s “landing” – it will literally have to bolt itself down to stay put on the surface of the comet – will arguably be the highlight of ESA’s year. But, as Ferri notes, the lander is only expected to survive about 60h; the real scientific “revolution” to come from this mission will be in the observations and measurements that Rosetta makes as it “escorts” Churyumov-Gerasimenko on its journey towards its closest pass to the Sun.

That escort mission will run through December 2015 – when the comet will be about 450 million km from the Sun and its “tail” of gas and dust so active as to risk destroying its companion spacecraft. But before that “ice limit”, says Ferri, a roughly 18-month close encounter with a comet – including many passes through the tail, to analyse the make-up of the nucleus – will have given scientists a mass of data on what he calls, after the Sun and the Moon, our “most connected” heavenly bodies.

And, apart from gathering data on the composition of one of the space-rocks that may, in their bombardment of Earth in the early Solar System, have brought us water and the constituents of life, Rosetta will have also put ESA at the forefront of a key spaceflight technology. When time comes to track other small celestial bodies – possibly to realise NASA’s goal of an asteroid-redirect mission or, forbid, to stick close to any asteroid on a collision course with Earth – engineers will call on the navigational techniques that intercepted and escorted Churyumov-Gerasimenko.

Even by the standards of intricate deep space exploration operations, Rosetta marks a milestone. So it is understandable if other high points of the second half of ESA’s 2014 seem rather pedestrian. But in more ways than just a comet encounter, this year – its 50th – is one of the agency’s most momentous.

One flight with potentially long-reaching implications is scheduled for November, when the fourth launch of ESA’s Vega light launcher will lift its re-entry technology demonstrator. The return trip for the Intermediate eXperimental Vehicle (IXV) will open a new era for ESA, which has not to-date developed the capability to bring payloads – or astronauts – back from orbit.

The 2t unmanned lifting body IXV features a large-panel thermal protection system that promises significant improvements over the small tiles that proved so problematic on NASA’s Space Shuttle.

IXV’s follow-on programme – PRIDE (Programme for Reusable In-orbit Demonstrator in Europe) – may result in a fully orbital, runway-landing vehicle. And, ESA and Germany’s DLR aerospace agency earlier this year reached an agreement with Sierra Nevada of the USA to jointly evaluate technologies such as those being developed for IXV for Sierra Nevada runway-landing Dream Chaser or other variants; launch byAriane 5will also be studied.

The appeal of such crew-friendly re-entry technology will be apparent in November, when German astronaut Alexander Gerst returns from his six-month stay on the International Space Station. Like every other ISS visitor in the post-Space Shuttle era, Gerst will come down in Kazakhstan; almost certainly safely, but definitely with a bump despite the parachute and landing rockets slowing his Soyuz capsule.

Never let it be said, though, that Europe rests when it comes to extending human civilisation to space. Gerst’s ESA place on the ISS will be filled later in November by Italy’s Samantha Cristoforetti, whose luggage will include a microwave oven-sized (but 20kg) machine developed by Italy’s Lavazza and space food specialists Argotec that – for the first time ever – will provide astronauts with a proper espresso. Given the high pressures and temperatures required, this is no mean feat in microgravity; anyone who has tasted astronauts’ coffee-in-a-tube will appreciate the realisation of what, surely, will prove to be one of the enabling technologies for any long-duration missions to, say, Mars.

Back on Earth, however, there may be many espressos required to fuel ESA’s activities through the end of the year. When the science and industry ministers of ESA’s 20 member state governments meet in Luxembourg on 2 December, the agenda will feature two transformative challenges.

One will be a go-or-no decision on the Ariane 6 heavy launcher programme. Conceived to replace the hugely successful Ariane 5 – and given the preliminary green light at the last ESA ministerial gathering, at Naples in November 2012 – Ariane 6 is being designed to fly for half the cost of Ariane 5, a saving seen as essential if Europe’s launcher programme is to be price-competitive with private sector start-up SpaceX. That competitiveness is, in turn, seen as a crucial factor if Europe is to retain its independent capability to access space.

ESA director general Jean-Jacques Dordain is expending huge energy this year to nail down the details of Ariane 6’s all-solid fuel and modular design. But equally important is to replace the multi-headed industrial structure behind Ariane 5 with a leaner – and much cheaper – concept, which has been proposed by Ariane prime contractors Airbus and Safran. Dordain, then, will have to convince the ministers both that ESA’s technical concept is sound, and that they should step back from a political model of funding and workshare that has guided ESA for half a century and accept what amounts to a contracting to the private sector.

On top of that, the December ministerial meeting will grapple with the details of the evolving relationship between ESA and the EU, which does not control ESA but now, under the so-called Lisbon treaty, regards space as within its remit. Since most but not all ESA members are members of the EU and not all EU member states are members of ESA, fruitful co-existence requires a deft political hand.

Dordain, a scientist by training and self-evidently a finely-tuned politician, regards the EU relationship as both a challenge and opportunity. The devil, as ever, resides in the details and it will be interesting to see how far the December meeting goes in spelling out the parties’ positions.

In any case, that ministerial summit will be the Frenchman’s swansong, as he steps down from ESA at year-end, after more than 11 years in charge. As for who will replace him, it is in principle Germany’s “turn” (an Italian, Antonio Rodotà, preceded Dordain). DLR chief Jan Wörner is thought to be the prime candidate, but Gaele Winters, a Dutchman who is now ESA’s head of launchers, is thought to want the job – and is an attractive candidate given that the next director general will have to drive Ariane 6 to completion.

Another name in the frame, and one to take seriously, is David Willetts. Britain’s minister for universities and science has been an enthusiastic champion of space, and the country has dramatically ramped up its financial contribution to ESA over the last couple of years.