Advanced Activity
Keeping It Cool This activity This activity was inspired by and developed with gned has been desi of n io ss Nikki Jahn, a STEM Ambassador. You can find Nikki’s profile on page three. for one se 40 minutes approximately to an hour. e During this activity you will e followed mor If the extras ar . ed ed ne be introduce ideas about keeping ll wi ns io ss se allow time materials and tools cool whilst You will need to The Solar Orbiter mission is looking to produce materials in space and try to encourage to prepare the e th images of the Sun and perform detailed in used the students to apply these ideas measurements of the sun’s properties. Those session. during a hands on activity.
Introduction
involved in the mission hope that this will help us understand how the solar system works.
The sun has a temperature of almost 6000 ºC and to perform its mission the orbiter will have to get very close to the sun’s surface. This means the orbiter needs a protective heatshield for the side which faces the sun. The instruments that look directly at the sun peer through this heatshield, which prevents the spacecraft from getting so hot that the materials melt and the electronics stop working.
This activity looks at the idea of keeping materials and apparatus cool whilst in hot conditions.
What You Need (The numbers needed will depend on the size of the group. Allow students to work in teams of two to four)
cabinet, oven or
✓ Warming eter ✓ Thermom ✓ Chocolate ✓ Scissors (tape or glue) ✓ Adhesive h ✓ Stopwatc ✓ Ruler of materials: ✓ A variety
in partnership with
hair dryer
l – thin metal foi tyrene) lys – insulator (po c pots) lk bottles, plasti mi – plastics (e.g. – cardboard, etc
have – Schools will e Ambassadors Note for STEM s you need, so check with th should t m many of the ite ur session. A risk assessmen yo n io ss se teacher before is th beginning be done before
What To Do Each team of students have to design, make, test and evaluate an appropriate heatshield to protect a square of chocolate from a heat source. In this instance the chocolate represents the payload of important equipment and tools on the solar orbiter and the heat source represents the sun. The students need to make a box to contain the chocolate square (the bottom of a polystyrene cup works well) and then think about which of the materials available will protect their chocolate from the heat. Students should research the different properties of the materials they have available. Do they need the material to be a good conductor or a good insulator? (Remember students can use a mixture of materials in their design, but they should give reasons for each material used.) If you wanted to expand this session you could ask the students to develop tests to determine the suitability of each different material in forming a heat shield for the chocolate. Once they have researched the materials available, students then design and make their heatshield for their chocolate. Remember we need to check and make observations on whether the chocolate has melted – so the students need to be able to open the box! To test the student’s heat shield, place the covered box into a warming cabinet or oven set at 50˚C for a set time (i.e. two minutes) to see if it protects the payload. Chocolate melts at body temperature so the oven does not need to be too hot. Alternatively you could heat the box using a hair dryer for a set time keeping the hair dryer a set distance from the box (e.g. 30cm away) during heating. To ensure the experiment is reliable make sure that the students have the same amount of chocolate, and the same heating method is used (for the same amount of time).
Questions to think about:
Q How well do the designs work at
keeping the chocolate cool and why?
Q How do the materials change over time? Q How could the design be improved?
[Reflective surfaces on layers facing the sun will reflect the heat more effectively]
It can sometime be hard to distinguish between degrees of melting when inspecting chocolate, so make this exercise more quantitative by including a small thermometer or thermocouple in the box.
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Curriculum Links You may wish to discuss these areas when doing this activity: England Science: Heating and cooling Scotland Science: Energy 3-04a, b
Explanation This activity looks at how the Solar Orbiter is being designed to protect its payload from energy transfer. There are three ways that energy can be transferred: Conduction – When a solid material is heated its particles gain energy, this energy causes the particles to vibrate. The more energy that is transferred the more vigorously the particles vibrate. The particles bump into nearby particles which causes them to vibrate. Thus energy is transferred from the hot part to the cold part of the material. If the substance allows the energy to move easily through it, it is a conductor. In contrast to a conductor, an insulator resists the flow of energy through a substance. Convection – The particles in a liquid or gas move. When particles have a lot of energy they move more quickly, transferring energy to areas with less energy. The net energy transfer is from hot to cold areas. Radiation – Radiation is energy transferred by electromagnetic waves. Electromagnetic waves (for example infrared) can pass through a vacuum; when they hit an object (e.g. the solar obiter) then can transfer their energy to the object. Space is a vacuum (no particles) and so conduction and convection do not occur. (Remember conduction can occur between the materials of the spacecraft itself, but not between the craft and space). Radiation from the sun would cause the exposed surfaces of the Orbiter to heat up very quickly. This energy could cause damage to the instrument payload so the heat shield is designed to reduce this energy transfer and keep the instruments at a stable temperature. The heat shield also needs to be thermally isolated from the spacecraft itself to stop the conduction of heat from the shield to the Orbiter. It is designed to have gaps between the layers of protective material to allow heat to radiate into deep space, rather than conduct directly into the spacecraft. Can you incorporate these ideas into the activity?
Handy Hints Designing for space has many challenges, for example you might encounter extreme heat, extreme cold, high radiation environments, dust storms on Mars, and much more. Start your session by asking what the students think it would be like in space; do they think it would be hot or cold etc? Then introduce the Solar Orbiter and the problems it may encounter (e.g. the extreme heat from being so close to the sun). Remember any materials available e.g. recycled plastics, foil or foam could be used for this session. Why not limit the amount of materials available to the students and see what ideas they can come up with? Do not eat the chocolate once it has been used in the test!
Profile: Who Uses These Ideas? Nikki Jahn Solar Orbiter Payload Interface Engineer, Astrium Nikki is part of a team who liaise with the instrument builders who are providing the 10 payloads for the Solar Orbiter mission.
Industry sector
Aerospace
How I got here
I studied for a degree in Physics at Imperial College. I was always very interested in space when I was younger, but didn’t realise the size or extent of the space industry in the UK until I started searching for graduate jobs. I got accepted into the Astrium Graduate Development Programme in 2006, and spent the next two years getting a good overview of spacecraft engineering and design.
My favourite part of my job
I travel quite regularly in Europe to see the instrument teams, the European Space Agency and NASA representatives that we work closely with. It’s a really interesting job for meeting fascinating, dedicated engineers from all across the world.
Likes
Thames /South Bank festivals, Glastonbury, New York and Secret Cinema.
Dislikes
I really can’t stand seafood!
The future
Like any space engineer working abroad is a career goal! It’s a great industry for stepping outside of your comfort zone and into another culture for work.
What is engineering?
Engineering is applying an understanding of physical principles to the design and manufacture of real-world things.
Some Extras... Why not see how long the chocolate lasts in the student’s designs before it melts? Check at one minute intervals. Look at the properties of different types of chocolate e.g. milk chocolate melts faster than dark chocolate due to the higher levels of fat compared to dark chocolate. Start with dark chocolate so that you have a larger temperature range to play with. The ideas can be taken further. Although the side of the orbiter facing the sun will be hot, the other side looks at deep space which is extremely cold. Can the students improve their heatshield
design to take account of this? It may be best to test your designs using a hairdryer in this instance. Spacecraft can be fitted with devices to carry heat from hot locations to cold ones, these are called heat pipes. (Some good, but rather technical explanations of the technology can be found here www.thermacore.com/thermal-basics/ heat-pipe-technology.aspx) Most space missions use heat pipes to transfer heat away from a hot place to a cooler one, however on the Solar Orbiter; the temperatures are so high the spacecraft is being designed to work without heat pipes! There are lots of ideas we can use when thinking about ‘designing for the space environment’.
Set the students another ‘Testing for Space’ scenario e.g. spacecraft have to survive a number of extreme environments like the forces on the craft when it is launched. Ask your students to build a spacecraft which has to protect their instrument payload (you could use an egg for this) from getting destroyed or damaged. You can use clean, recycled plastics and card. Use a plastic storage crate being shaken side to side to test their designs.
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This is Engineering? Many of the ideas and skills demonstrated in this activity are essential for engineering, in particular Aerospace Engineering. Aerospace engineers look at the design, construction and science of aircraft and spacecraft. Generally you will need STEM A levels (Advanced Highers in Scotland) including mathematics and preferably physics too. Alternatives include STEM-related Advanced Diplomas (or BTEC National Extended Diplomas) plus appropriate qualifications in mathematics and possibly physics too. See www.ucas.com for more information. Related Subjects: Materials Engineering If students found the ideas presented in this session interesting then an apprenticeship in Heating, Ventilating, Air Conditioning and Refrigeration may be of interest. This is a broad industry with many occupations available to apprentices at the intermediate and advanced level. Visit www.apprenticeships.org.uk for more details. Apprenticeships can start at age 16 and students will need GCSES including English and Maths. In Scotland visit www.apprenticeshipsinscotland.com and in Wales wales.gov.uk/apprenticeships
Extra Maths Kelvin, K is a unit of temperature which Scientists and Engineers use. We can use the following equation to convert from degrees Celsius to Kelvin: [K] = [°C] + 273.15 Can you calculate the following in Kelvin?
Q The temperature of the Sun Q Room Temperature Q Body Temperature
Next Steps Visit the European Space Agency website for more details on the Solar Orbiter Mission http://sci.esa.int/science-e/ www/area/index.cfm?fareaid=45 For more information on Astrium visit www.astrium.eads.net Remember there are more resources at networking. stemnet.org.uk For more on STEM Clubs visit www.stemclubs.net For more information on Engineering: www.raeng.org.uk For even more space resources visit www.esero.org.uk the European Space Education Resource Office The STEREO website http://stereo.gsfc.nasa.gov discusses another mission looking at the sun, this time working towards being able to see the structure and evolution of solar storms as they blast from the Sun and move out through space. You may also find the NASA Sun-Earth system web page useful www.nasa.gov/topics/solarsystem/ sunearthsystem/main/index.html CREST Awards are easy-to-run, encourage students to continue with STEM subjects, and add real value to UCAS applications. To link this activity to CREST Bronze Awards, contact your CREST Local Coordinator: www.britishscienceassociation. org/crestcontacts Finally, www.our-space.org has lots of useful videos and materials for further work on space.
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