STEM

This project is a design study looking at options for recovering an object dropped into a nuclear reactor. How do we overcome the problems of difficult and restricted access into an environment with a high radiation field, to find, pick-up and remove a small object, without causing additional damage. I used this project for a number of years with Yr10/11 students aiming for Silver CREST and some of the off-the-wall ideas they came up with, it turned out, were being seriously investigated in university labs.

Pre-job brief for students starting the project. (Notes pages from a Powerpoint presentation.)

There are many situations where humans need to enter potentially dangerous environments, such as clearing areas contaminated by toxic or radioactive waste. Using modern technology, is it possible to effectively equip humans with additional senses (an "augmented reality") so that they become more aware of the hazards that they will encounter?

I used this project with Yr10/11 students aiming at Silver CREST and some of wild new ideas coming from university labs that we looked at a few years ago are now actually being deployed in real World decontamination projects. We need some new wild ideas! 

Pre-job brief for Hazardous Environment Entry project

We are running out of some rare chemical elements that are irreplaceable in many technological applications (including making smart-phones). When current ore bodies are exhausted it may prove cheaper to mine these metals from asteroids (where they may be present in high concentrations) than to attempt recovery from low-concentration Earth rocks, or even from recycling.

This is a challenge that could be approached at several levels, making it suitable for both a Silver and Gold CREST project. (The later would require a more sophisticated and quantitative approach.) 

This is partly a problem of planetary science (where do we find asteroids, what are they made of?), space flight (how do we get to asteroids and how do we mine them?) and energy (how much energy does it take to get a kilogram of, say, tantalum from an asteroid back to Earth? Where would we get it from?). 

Project brief for Space Elevator Design Study

Space Elevator Physics 

The idea that we might get into space by climbing a cable dropped from a geostationary counterweight has been around for over a century, both as a serious engineering proposal and as a basis for science fiction stories. It is, however, only relatively recently that new materials such as graphene are approaching the strength-to-weight ratios that would make the concept a practical possibility. Serious engineering companies have done design studies to investigate the issues.

What are the advantages of such a technology? Would it really be a cheaper way to get to space? What are the remaining technical barriers? How likely is it that these barriers might be overcome? Even if we do not use it to escape the Earth, would it be worth thinking about for getting to and from Moon-orbit to a Moon base? What are the safety issues? (E.g. what would happing if the cable broke?)

This is a challenging project for a Gold CREST award that requires a team who are prepared to do some mathematical calculations to support a design study, as well as investigate the material science and engineering issues. It is essentially about force, energy and strength.

We currently drive spacecraft around the Solar System using limited supplies of fuel: when it runs out the planetary exploration mission is unable to do further manoeuvres. It has long been suggested, however, that it would be possible to use the pressure of the light from the Sun as motive power, "sailing" the Solar System on inexhaustible fuel. It even turns out that we can "tack" against the light, moving towards as well as away from the Sun. Although the pressure on a light sail is very small we can imagine constructing very large (km-sized) sails that generate small but non-negligible acceleration that can be maintained for long periods. Such small accelerations can build up over time and even compete on interplanetary travel times with conventional rockets (which have to do short-but-sharp accelerations and then long periods of coasting).

Recent advances in material science may make such sail a practicable possibility. 

What are the technological constraints on solar sail design? What can we achieve with current materials and with those that we can reasonably anticipate within decades? How long would such craft take to reach the outer planets and return?     

This project would challenge Yr 12/13 students aiming at Gold CREST who would like to understand how physics is applied in real-life engineering situations. It involves applying concepts of energy and force (both from the momentum change of reflecting photons and gravitational attraction).

The original idea for this study came from a Year 12 student who wanted to study the problems of getting astronauts to Mars in good health. He wanted to focus on the effects of radiation and whether it was possible the shield the astronauts, and he asked whether it would be possible to deflect incoming cosmic rays with a magnetic field, since conventional shielding against radiation requires adding a lot of mass to the spacecraft.

Surely, he reasoned, magnetic fields weigh nothing, and we could use super conducting coils to create them without continuously using energy. This sounds like it ought to be an easy win.

There are, however, no completely free lunches here. Very strong magnetic fields would be required in order to be an effective shield and strong fields try to blow apart the coils used to generate them, so we have to add mass to hold everything together. The question is how much mass is required, assuming that we can use the strongest, lightest materials available? How would this mass compare to a conventional shield of equal effectiveness?

It turns to that we can make a good estimate of these figures using only A-level maths and physics.

You are told that astronomers have identified a near-Earth asteroid in a potentially dangerous orbit. There is a non-negligible probability that it may strike the Earth in the foreseeable future - though it is known that the orbit will not intersect Earth’s orbit for at least two decades (and further refinement of the orbit after more intensive observations may indeed push the point of maximum risk back by one or two decades).

Initial observations suggest that the asteroid is uncomfortably large, probably at least 300m in diameter (capable of devastating a country the size of the UK in a direct strike) but perhaps as large as 1000m (capable of causing continent wide damage). You are part of a team that is charged with preparing an orbit-deflection plan, taking account of the fact that different (and less difficult) approaches may be possible with longer lead times (say 40 years) and smaller asteroids. If, on the other hand, the lead time turns out to be short and the asteroid larger than hoped, more aggressive methods may be required (perhaps using nuclear explosions)

You are now required to do some scoping calculations of possible alternative ways to handle the problem. This is very common at the early stages of a project: we look at a number of alternatives and see which is likely to be the most promising strategy, before investing a lot of time doing very detailed and complex planning on the selected option.