On 25 December 2003 space exploration fans expected an extra Christmas gift. Beagle 2, a robotic spacecraft was to descend on the dusty plains of Mars. Once settled there, the tiny probe would play a musical call sign then start to photograph and poke the Martian soil in search of evidence of Martian life past or present. Excitement was highest in the United Kingdom as this was the first British attempt to explore another world. Sadly something happened to the little robotic explorer and there was no message from Mars. Ten years later, whatever happened to Beagle 2?

Currently in storage, this full-size replica of Beagle2 was display in our Exhibition Area for many years. (Image credit: Robert Hill/Armagh Planetarium)

Currently in storage, this full-size replica of Beagle 2 was displayed in our Exhibition Area for many years. (Image credit: Robert Hill/Armagh Planetarium)


Exploring other worlds is something we just don’t do in the UK. We’re great at astronomy, astrophysics and space science, and we have made some wonderful kit carried on other people’s spacecraft, like the Huygens’ Surface Science Package currently on Titan. We have even built interplanetary spacecraft, notably ESA’s Giotto, but we don’t organise our own missions.  That would be a step too far.

Beagle 2 is the exception to the the traditional apathy and caution. Beagle 2 looked as though it could be the start of an exciting new phase in British science. Very surprisingly, Beagle 2 (“Beagle 1” was HMS Beagle, the Royal Navy sloop which carried the young Charles Darwin on one of its voyages of discovery) was not a government-originated project, rather it was proposed by British scientists led by Colin Pillinger (1943-2014) of the Open University.

Beagle 2 was a very different Mars lander. It would be cheap, costing $50 million (US)  to develop and build. It was to be carried across space by ESA’s Mars Express spacecraft and released above the Red Planet.  It would be built and controlled by a consortium of academic institutions and private companies, and although Pilinger and his colleagues expected some financial contribution by the UK’s taxpayers they anticipated much of the finance to pay for it would come from commercial sponsorship. UK retailers and consumer goods manufacturers were expected to be eager to pay to have their logos displayed on the probe.

Beagle 2 was a tiny, innovative design; weighing 69 kg at launch, the lander was shaped like a shallow bowl 0.65 m across and 0.25 m deep. It was to use parachutes to slow itself down and airbags to cushion its landing on Isidis Planitia.  Once safely down the hinged cover of the lander was to open, allowing the solar panels to unfold and exposing the interior of the craft with its UHF communications antenna and scientific instruments to the Martian sunshine.

Beagle 2 packed some potentially ground-breaking scientific equipment into so small a package. Some of the instruments were on Beagle 2’s robotic arm, the Payload Adjustable Workbench (PAW), including a pair of stereo cameras, spectrometers, a microscope with a light source and a drill for collecting rock samples to be passed inside the probe for analysis. A small mechanical mole called PLUTO (Planetary Undersurface Tool) was attached to the probe by a cable. This unique device would have burrowed into the Martian soil to investigate what lies beneath the surface.

The jovial and hirsute Pillinger, fitting perfectly the British image of a scientist as a middle-aged eccentric white male boffin, was the public face of Beagle 2 and was happy to talk up the project to the media. However behind the scenes, development of Beagle 2 was far from easy, it was an extremely ambitious concept and some members of the consortium and their subcontractors building it had limited experience with space technology. The project was rushed to meet the Mars Express launch deadline and short of cash as the anticipated flood of commercial sponsorship never happened. Beagle 2’s construction was in the end only possible because of financial support (to the tune of £22 million) from the British National Space Centre (forerunner of today’s United Kingdom Space Agency) and ESA.

Beagle 2 was delivered to ESA on time but not on budget, it cost £66 million to build, nearly twice the predicted amount but still extraordinarily cheap for a planetary lander. Beagle 2 and Mars Express were launched on a Soyuz from Baikonur Cosmodrome, Kazakhstan on 2 June 2003. They sailed serenely across interplanetary space together until 19 December 2003 when Beagle 2 was released from its mothership. What happened after that is a mystery to this day.

Between being set free from Mars Express and its planned landing, Beagle was mute by design, it could not send telemetry home until after touchdown. The planned musical call-sign (provided by Blur) to acknowledge the probe had landed and deployed would have been the first sign of life after separation for Mars Express but it was never received. There was still optimism that the probe might make contact with home all through January 2004 but by 6 February 2004 it was clear Beagle 2 was just another failed Mars probe. Mars Express has gone on to be a huge success and is still adding to our knowledge today.

What did happen to Beagle 2? Regrettably to this day no one knows. Pillinger suggested that Mars itself was to blame, he believed that a hypothetical unexpected variability in the Martian atmosphere’s density had meant the parachutes had not been able to slow Beagle 2’s descent sufficiently. ESA and the UK government held a joint investigation and eventually (after some pressure from New Scientist magazine) published a 42 page report. This is a fascinating, depressing and at times astonishing read. After reading this report, it seems to me that Beagle 2 was doomed from before it was even attached to Mars Express.

Rather finding a possible cause for the loss of Beagle 2, the report found multiple potentially crippling weaknesses in the probe’s design, construction and management (Pillinger’s suggestion that the Martian atmosphere was to blame was discounted). Of these, the report’s authors suggested several as especially likely causes of failure.

  • There was a significant chance of the probe’s heat shield back cover, which was to be jettisoned during its descent, colliding with the probe parachute and preventing its proper deployment
  • The cushioning air bag design was “not robust” and inadequately tested. It was estimated to have a one in four chance of failure. This means even if every single other component in Beagle 2 had worked perfectly there was only a 75% chance of it landing successfully.
  • Even if the air bags worked correctly, there was a chance of them separating early from the lander, causing it to be smashed against the unforgiving rocks
  • On landing the airbags could potentially bounce Beagle 2 upwards, entangling it in the parachute.

The report also describes how Beagle 2 unexpectedly vented gas (probably water vapour from sublimating ice) throughout its time attached to Mars Express. Not only that but images taken immediately after its release from Mars Express show unexpected debris (at best ice particles) were thrown off it and “an anomalously bright area” on the probe itself.

The last view of Beagle 2. Note the bright area on the probe and one of the pieces of unplanned debris. (image credit: ESA)

The last view of Beagle 2 from Mars Express. Note the unexplained bright area on the probe and one of the pieces of unplanned debris near the bottom of the picture. (Image credit: ESA)


Many smart people invested an enormous effort into Beagle 2 and produced an innovative concept for a spacecraft. I cannot imagine how crushing its failure must have been to them. Undaunted, in 2004 Pillinger suggested Beagle 3 (also known as Beagle 2: Evolution) to ESA but not unexpectedly this proposal fell on deaf ears. Disappointingly, he later is reported to have made churlish comments on the success of NASA’s Curiosity lander.



Beagle and its discarded cover. (image credit: )

Beagle and its discarded cover. (image credit: HiRise/NASA/JPL/University of Leicester )


Beagle 2 on Mars (Image credit: UKSA)

Beagle 2 on Mars (Image credit: HiRise/NASA/JPL/University of Leicester via UKSA)


On 16 January 2015 Beagle 2’s resting place was announced. Images from the HiRise camera on the Mars Reconnaissance Orbiter (MRO) showed that the parachute system had indeed functioned as designed and Beagle was resting on the Martian surface in the expected landing area about 5km from its centre. However the images showed that only two, or possibly three, of the petal-like solar panels had deployed correctly, the undeployed panels would have  blocked the RF antenna which would transmit data to Earth.  Why this failure occured is still unknown. Perhaps the ESA/HMG report authors’  suspicions about the airbags were correct: Beagle could have been critically damaged by a hard landing or the solar panels blocked by debris from a malfunctioning airbag. Alternatively the cause of failure could have lain in some unsuspected component, some minor cable or actuator experiencing a one in a thousand malfunction. We won’t know for certain until some future explorer inspects Beagle 2 in its alien home. Seeing the little robot at rest and intact makes the mission’s end even sadder, it was almost a success!




Beagle 2 failed, a fact which saddens me. A successful Beagle 2 might have made astonishing discoveries about the potential of Mars as an abode for life. It could have inspired a new and more dynamic era for UK space exploration, and might have made science and engineering cool to a new generation. Its failure was a disaster the UK space community has yet to recover from.


Further reading

Spufford, Francis, Backroom Boys, Faber and Faber, 2004

Day, Dwayne A, A Different Kind of Openess, Thespacereview.com, 2005

Day, Dwayne A, A Very Sick Dog Indeed, Thespacereview.com, 2005

R. Bonnefoy et al. Beagle 2 UK/ESA Commission of Enquiry, 2004

(Article by Colin Johnston, Science Education Director)




Joshaua · August 16, 2015 at 21:42

The fact that the only pobe that had.equipment to research below the soil of mars malfunctioned is intriguing.aybe someone or something doesnt want other species below the soil of mars…

LaurentA31 · January 16, 2015 at 12:59

Great news,
For people who love spending time exploring the Martian land, you can do it on Mars like you are used to do it with Street View by Google) on Earth . Enjoy this amazing interactive 360° exploration following the space rover Curiosity :

Janet Wright · May 8, 2014 at 09:48

Colin Pillinger’s infectious enthusiasm sparked a lot of interest among people who hadn’t previously taken much notice of space exploration. Sad to hear today that he has died. RIP a genuinely popular scientist.

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