The Beagle has Landed & Lunar Mission One Takes Off
On Christmas Day 2003 a sizeable proportion of the UK public joined Professor Colin Pillinger in the anxious wait to hear a tune composed by the band Blur, emanating from the Planet Mars. It would have signalled the successful arrival of the UK space probe Beagle 2 on the surface. We never got to hear the tune: Beagle 2 had vanished.
The blow to UK national pride was pretty heavy, perhaps made worse by the news a few weeks later that two NASA exploration rovers called Spirit and Opportunity had landed on the same planet and were fully operational. The comparison of UK failure to US success is grossly unfair however, when you consider the funding difference alone: Beagle 2 cost about $80m, the MER project topped $820m. I have heard it said that there were sighs of relief from some in NASA when it became apparent that the UK mission had failed. If it had succeeded, questions would have been asked in US treasury circles as to why the NASA mission cost over 10 times as much. Again not fair, but politics always rules in matters of public funding, not logic. The UK government gave up on space development long ago, but Professor Pillinger was a driven man: he wanted to send a probe to Mars to look for signs of life, current or extinct. The story of Beagle 2 bears no resemblance to that of the huge-budget US projects such as Apollo or indeed the Mars Exploration Rovers. Pundits said that it was a typical British ‘sticky tape and string’ affair, never likely to succeed. When Beagle 2 disappeared, the standing of UK engineering in the world took another lurch downwards. Pillinger did his best to be positive, citing all the valuable lessons learned from the design process. But the fact is, until last week, all we knew was that the mechanism for launching the probe away from the orbiter Mars Express had done its job. The official post-mortem report on Beagle 2 published in 2009 can be downloaded from here.
But why did Beagle 2 fail? The basic answer is that space exploration on that scale cannot be done on a shoestring budget. Not only that, but in the case of Beagle 2, the process of getting funding carried on throughout the design/development/production process. Constant demands to reduce weight coupled with the desire to get maximum ‘value for money’ by cramming in as much science as possible took its toll. Two limitations of the design, obvious to all before launch contributed to the crushing disappointment on that Christmas Day. Firstly, there was no telemetry available from Beagle from the time it left Mars Express until it was fully deployed and operational on the surface. Hence when the lander failed to ‘call home’, its fate was unknown: did the aeroshell fail in the heat of entry, did the aeroshell separate, did the parachute open, did the ‘airbags’ inflate and were they effective, did all the ‘petals’ open? Did it even reach Mars or did it miss and fly past? Although we cannot repair Beagle 2 and enable it to carry out its mission, that picture of the lander on Mars finally vindicates Pillinger’s assertion that the project was not a total failure. It’s a shame he never lived to see it. Those few pictures say it all: the untested landing systems worked, it came down exactly where it was supposed to, and only the second design limitation probably prevented us from hearing that signature tune.
The need to pack all the science kit, communication systems and of course the solar panels into such a tiny space led to its folded clamshell form. There were five ’petals’ and they all had to open fully before communication could be established. The pictures suggest that two did not open for some reason. Each of the hinge mechanisms represents a single-point failure node, that is, the failure of any one to operate is catastrophic for the whole mission. We may never know why they didn’t open, although future even-higher resolution pictures might reveal that an airbag didn’t roll out of the way after landing. The fact that some did open suggests that the airbags were probably successful in achieving a relatively soft landing. Single-point failures can be difficult and expensive to design out as the solution often involves duplicated or ‘redundant’ equipment. If funds are tight (or in the case of spacecraft, weight budgets) redundant systems tend to be sacrificed and then it all comes down to luck. Even the comet lander Philae nearly didn’t make it when the single thruster designed to hold it down on the surface failed to fire. Fortunately this wasn’t a catastrophic failure as Philae was able to get down and (eventually) do some data gathering before its batteries ran out. Even so, the resulting ‘bounce’ into shadow may have given it a very short life.
In the early 1990’s NASA adopted a ‘Better, Faster, Cheaper’ philosophy with spacecraft development in order to cut costs. This approach was taken too literally and is generally credited with causing the loss of two spacecraft in 1999, Mars Climate Orbiter and Mars Polar Lander. While it can be said this approach can be made to work with terrestrial pursuits, it is entirely questionable for unmanned spacecraft that may have to function for long periods in a poorly-known harsh environment with no maintenance available. These are exploration vehicles after all. That’s why redundant systems, a concept hated by accountants, must be used if total mission failures are to be avoided.
Now in 2015 a new UK space project is underway called Lunar Mission One. This time public funding appears in a new form: crowd funding with a successful Kickstarter campaign raising the first £600000. The aim is to land a probe on the moon which will drill deep into the ground to study the rock beneath the surface regolith. This is the point where the investors get their reward: a digital memory capsule buried in the drill hole. Of course this is only the start of at least 10 years of fundraising, development and construction. I’ve contributed my £30, but somehow I’m not inspired. In 2003 a sticky tape and string project went to Mars and came within a hair’s breadth of a stunning achievement. With better and consistent funding, with engineers able to design for success rather than compromise for cost, things might have been different. Twelve years later has anything changed? At least the UK government did in the end grudgingly support Beagle 2; now it looks like UK space science is going to have to depend on a continuous stream of marketing gimmicks keeping the public interested for the next ten years. Even if it gets off the ground, it’s only going as far as the moon. Last year the Chinese landed a rover on the moon and India placed a satellite in orbit around Mars at their first attempt. I can’t see this project inspiring the next generation of engineers: it feels too much like running to catch up from a long way behind. I do hope I’m wrong.
If you're stuck for something to do, follow my posts on Twitter. I link to interesting new electronics components and development kits (some of them available from my employer!) and retweet posts I spot about robot, space exploration and other issues.