Rollercoaster Ride to Mars
On December 25th 2003 the Beagle 2 probe was scheduled to land on the surface of Mars, in an attempt to identify whether life once existed on the on the planet. Scientists from all over the UK and abroad gave up their Christmas morning in the hope of seeing their probe land on another world. Unfortunately the deadlines passed one after another and it became clear that the tiny craft had failed in the last moments of its 50 million kilometre journey. An investigation was launched to determine the cause of Beagle's failure; however it provided no concrete answers as to why Beagle was lost. A number of people believe that it was the descent system which failed. The following exercises will allow you to determine whether you agree.
Shortly before its scheduled landing Beagle 2 would have hit Mars' atmosphere at a speed in excess of 14,000 mph. As the probe ‘hitched a lift' with the Mars Express orbiter, the permitted mass had to be extremely limited. The entire Beagle 2 probe, with its heat shield, had a mass of less than 65 kg (no room for rockets to slow it down) this was a massive technical challenge, and was made worse as the design phase of the mission progressed. The matter is made worse by Mars' thin atmosphere that means that re-entry friction will only slow Beagle 2 to 700 mph, and parachutes will be very inefficient in slowing it further. The Beagle 2 engineering team designed a landing system to slow the craft as much as possible. Even so the probe will still have to survive a jolt equivalent to pushing your PC off of your desk on to solid concrete!
Students are given the task of designing a landing system for their own B eagle 3 (a raw egg). Depending on the age and ability of the group the drop height could be as low as a desk or as high as… well, how high can you get? The aim is to land their Beagle 3 without damaging the egg. Since there was an absolute limit to the mass of the real Beagle 2, every gram that was used to protect the scientific payload was a gram that was effectively lost. To reflect this, the winner will be the team that lands their Beagle 3, without damage, and with the least mass.
Sci 4.2 d) The ways in which frictional forces, including air resistance, affect motion [for example, streamlining cars, friction between tyre and road].
Sci 4.2 g) The quantitative relationship between force, area and pressure and its application [for example, the use of skis and snow boards, the effect of sharp blades, hydraulic brakes].
Sci 4.2 b) About factors affecting vehicle stopping distances.
Sci 4.2 e) That balanced forces do not alter the velocity of a moving object.
Sci 4.2 f) The quantitative relationship between force, mass and acceleration.
Sci 4.2 h) How the forces acting on falling objects change with velocity.
Sci 4.2 i) Why falling objects may reach terminal velocity.
OCR GCSE science syllabus A (4.2 (28)) Apply the relationship (F=ma) to seat belts and crumple zones.
OCR GCSE science syllabus C (4.2.1 (14)) Know the measures taken to reduce injuries in the event of collisions (inc. body design seat belts & air bags).
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