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Category: <span>Digital Competition</span>

Size and Scale in Space

Rescue missions in space are very different to Earth. Knowing how size and scale in space is like can help you design for this successfully.

by Neelesh Ravichandran, UKSDC Design & Publications Committee Chair

Where is everything?

Space is a vast expanse filled, mostly, with nothing at all. The diagram on the right of this article shows to scale: the Earth, the Moon and the distance between them.  Unlike in the movies where astronauts travel between planets in minutes, real space travel is a little bit slower than that.

The Apollo 11 mission to land on the Moon took three days to travel from its launch pad here on earth, to touch down on the surface of our moon. For those three days, the brave astronauts had to rely on their spaceship for all their needs. This ranged from food to sanitation, and really pushed the limits of 1960s technology.

How far are things from each other?

As we can already see, the moon is very far away from the Earth (384 thousand kilometres away to be exact). However, the distances to other planets are truly astronomical. In fact, the average distance between Earth and Mars is 362 million kilometres, which is a thousand times further than the Moon.

Everything in between Earth and Mars is just empty space, with the occasional asteroid floating through. Our Apollo crew would take a whole year to get from Earth to Mars, and that’s if they get lucky with the time of year that they launch from.

How long does space travel take?

Well it really depends on where you need to get to. If you’re designing a rescue craft that is meant to save people all across the solar system, you are going to need to design it to be lived in for years on end.

Some journeys can be made faster with advanced thruster technologies, that can make the spacecraft reach their destinations faster. Be careful though, the more powerful your thrusters the larger your fuel tanks need to be. This means to reach far away destinations quickly, your rescue craft will have to be equipped with powerful thrusters and large fuel tanks.

How do you design a spacecraft to keep working for years?

Spacecraft are very precise and powerful machines, but they can be fragile in space. Here, even a simple fleck of paint can punch a hole in a spaceship. So, to journey to the edges of the solar system and rescue stranded crews, your spaceship must be built robustly, with protections against small impacts from debris floating in space.

Food and water

If we want to keep our rescue crew alive for these long missions, we need to keep them fed and hydrated. Food can be dehydrated and kept very compact; this means that if you’d like you can pack enough food into your rescue ship for the whole journey.

Water is a more difficult resource to manage. You’ll have to carefully recycle all the water that your astronauts consume so that you don’t run out on your journey to the rescue site. It would be terrible if your rescue crew needed rescuing because they ran out of water!

Think of ways astronauts can reduce the water that they use, and how to recycle any water that might otherwise be wasted.


Keeping your spacecraft pointed in the right direction is a difficult task. Unlike on Earth where we can use a compass to tell where north is, in space there are fewer ways to really work out where you are.

You will need to design a way so that your spacecraft can work out where it is. It could use the stars to work out its location in the solar system, or it could even try contacting ground stations you have already installed on planets.

Rescue tool

When you are performing rescue missions in space, you might need some special tools to help you get to the stricken crew. This process might require your rescuers to perform spacewalks or cut into a broken spacecraft.

Make sure your spaceship is well equipped with the latest technologies and tools that can aid its operators to save the people who are in danger.

Let’s bring them home

We look forward to seeing how you are going design spacecraft that can travel through the vast expanses of space. We want to see how you’ve solved the challenges brought by long distance space exploration, and hope that your designs can help bring our crew home!


“Houston, We Have a Problem”

The real space rescue missions of history.

by Nadiya Ivahnenko, Galactic Challenge Volunteer 

Monday, April 13th 1970

7.07 pm PST

56 hours into a mission, an explosion begins to shake a rocket headed for the moon. 205, 000 miles away alarm lights begin to flash at mission control on earth. Oxygen tank 2 has exploded, a whole side of the spacecraft is missing and three men are on board a space vessel that is seconds away from losing all power.

The Apollo 13 mission would mark the third manned landing on the moon, ultimately arriving at the bright plains of the Fra Mauro lunar highlands. The landing site promised to be dangerous with unpredictable hills, but with a wealth of scientific information from the remains of one of the largest craters discovered within the solar system; looking out of your window at night, you can see it for yourself as the darkest spot on the Moon! (See left)

April 11th 11.13 am

The crew of Apollo 13 climbed onto the Saturn V Rocket at Florida’s Kennedy Space Station. Meanwhile dozens of scientists, engineers and technicians stand by at mission control at Houston, Texas in the US, prepared to monitor the millions of moving parts on board.  After lift-off the astronauts entered Earth’s atmosphere, bracing themselves as the engines ignited and roared to life, shaking the ground around it. The first stage is successful and soon the rocket hurtles through the sound barrier – travelling faster than the speed of sound!

Strapped into their seats the astronauts furiously shake with the ship around them, as they ‘pogo’ into space. Suddenly the first alarm starts to ring as the centre engine fails – the first unexpected danger on their trip. Nonetheless, the team has planned for this and the computer onboard detects the failure, quickly powering up the remaining engines to recover.

The astronauts continue their course and are ready for a three-day journey to the Moon.

In the meantime, the astronauts wait, monitor the ship, and broadcast on TV every evening, showing the world as they travel deeper into space. Unknown to anyone, damage had emerged on the mission’s oxygen tank during testing, waiting for an ultimate disaster. See the Apollo 13 spaceship below, made up of service and command modules, alongside a lunar lander.

Two days after leaving Cape Canaveral, the crew is instructed to turn on the fans in the oxygen tank as part of a routine procedure, stirring the super-cold liquid oxygen inside. A bang rings out through the ship.

The astronauts gather in the command module to try and discover the cause of the explosion. The commander, Jim Lovell, radios mission control delivering a daunting message:

“Houston, we have a problem”.

Seconds later the plumes of oxygen are escaping into space and the fuel cells have failed causing power onboard to drop rapidly. Immediately both the crew on earth and in space are in a race against time, working against the odds to ensure the astronauts return safely. Across the world, people listen in on radio and TV news broadcasts as the events of the rescue mission unfold.

The mission is aborted and the crew move into the service module originally intended to land them on the Moon, now they must use it as a lifeboat. New computer code is drafted, radioed to the crew and punched into the onboard computer. For four minutes and 23 seconds the lunar lander’s engines fire and the crew manoeuvre around the moon, assisted by its gravity, and Apollo 13 has successfully begun its journey home.

However, the two-person lunar lander soon is unable to provide clean air for the three astronauts tightly squeezed on board. Using only the materials onboard the lander, an air hose from a spacesuit is cut and reattached to canisters onboard allowing breathable air to re-enter the lander.

Slowly earth reappeared in the windows of the ship. As they travelled more problems emerged: the engine had to be refired in bursts so the lander would not run out of fuel and miss the earth by 2,500 miles; a precise pressure had to be calculated to separate the astronauts from the unused modules of the ship; and lastly the astronauts needed to parachute into waves of the South Pacific Ocean.

At the time of the first explosion, there was a 10% chance that the mission would return. Still the mission persevered, and finally through creativity and improvisation the crew of Apollo 13 returned home. Though the mission failed in its original goal, Apollo 13 demonstrated the lengths that human teamwork could achieve. Still today, every mission into space carries the risk of no return, as well as a team of people waiting for the unexpected. Since Apollo 13, many astronauts have had to encounter near-disasters and many have been prepared to once again radio back the same message as Jim Lovell, “Houston, we have a problem”.

The crew of Apollo 13, after landing back on Earth


Halley’s Comet – A Bad Sign for Difficult Times?

Halley’s Comet has been seen throughout history as a warning of bad things to come – read on to find out about its history, science, and the challenges you might face living there!

Written by James Hayes, Galactic Challenge Volunteer 

Illustrated by Saffron Zainchkovskaya, Galactic Challenge Volunteer 

Imagine you’re living in the Year 1066 AD. William the Conqueror is invading Britain and suddenly, every night, there is a strange bright light in the sky with a long, brilliant tail. It moves slowly across the sky, lasting for a few months, and as it does, lots is changing in your life. You’d be forgiven for thinking that maybe this alien light had something to do with it all! Those at the time certainly did, with the Comet even depicted on the famous Bayeux Tapestry (see above).

For thousands of years, ancient civilisations would see this light in the sky and wonder just what it was, but it wasn’t until 1705 that an Astronomer named Edmond Halley would begin to understand just what it was. Edmond realised that the sightings of a comet every 75 years were not coincidences, but they were actually the same comet returning periodically, and in 1705 he predicted when it would return again. Halley said the comet would reappear in 1758 and indeed it did! Halley’s Comet is the only known comet with an orbit that allows it to appear in the night sky twice in a human lifetime, and we know that the next time it appears will be in June 2061.

This is where lots of science can take place – we have 40 years to plan all sorts of exciting experiments on the comet before it returns and lots of questions to answer. One question is about its orbit as it actually orbits in the opposite direction to all of the planets! The planets also orbit in circles around the sun, but Halley’s Comet has what is known as an “elliptical” orbit, meaning its orbit looks like a circle that has been squished. This is quite unique for objects in our solar system, and means that the comet gets very close to Earth but also moves away from it very quickly (as seen below).This could be a problem if something goes wrong on a mission to the Comet, as there would only be a limited amount of time for a rescue operation – in the year 2061, your Space Rescue Organisation is able to make the journey in two months, but time is a precious resource! 

The comet itself is about 15 kilometres long with a diameter of 8 kilometres, in the shape of a peanut. It is made mainly of ice, with small amounts of carbon, methane, and ammonia. As Halley nears the sun, many of these elements on the surface begin to turn into gases, creating the tail, or “comal”, which gives it its distinctive appearance. Because of its small size, any astronauts on the surface will effectively be in zero gravity – creating all sorts of opportunities for science and fun, but also creating problems you will have to solve. 

Halley’s Comet is a fascinating place, where we can discover secrets of our solar system, but it has the potential to be very dangerous. Perhaps those ancient civilisations that viewed it as a warning were on to something after all… 


How Do Spaceships Move In Space?

Exploring the ins and outs of spacecraft flight control, focussing on the systems that control propulsion and orientation.

Written by Abdur-Raheem Kalam (Heemy), Galactic Challenge Volunteer 

Illustrated by Saffron Zainchkovskaya, Galactic Challenge Volunteer 

Moving around becomes surprisingly difficult when we enter space. How do spacecraft go forwards, backwards, side-to-side? What happens when we need to turn around? And if we start to veer off course, how do we nudge ourselves back into the right path? At its core, all these questions can be answered using that familiar textbook rule, Newton’s 3rd Law – for every action, there is an equal and opposite reaction. Apply a force in one direction, and you’ll move in the other. Despite how crucial this fundamental law is to space flight, it still leaves some holes in our understanding of movement in space, holes which we need to fill.

Let’s think about a moving spaceship, hurtling through the Kuiper Belt on its way to Halley’s comet. We can describe the spaceship’s movement as a vector (specifically, as velocity) – that is, a property describing (1) the spaceship’s speed, and (2) the direction in which it travels. Therefore, by changing our spaceship’s velocity, we can move our spaceship in any direction and speed of our choosing – all we need is to vary these two variables. To achieve this, we require full, accurate and reliable systems of controlling speed and direction. It is these systems of control that underpin the flight and manoeuvres of our spaceship.

Controlling Speed

For us to control speed, engineers design a propulsion system. The propulsion system is what is most commonly associated with space flight – it’s the thrusters at the back of the spaceship that move the spaceship forward. They do this by expelling material out of the engine, in doing so generating a force that accelerates the rocket forward (starting off slow, but building up speed over time).

There are two main types of spacecraft propulsion systems – chemical and electric. Chemical propulsion involves burning a fuel to produce thrust. Take two elements, hydrogen and oxygen. These are combusted (burnt) together, undergoing a chemical reaction, forming water whilst releasing heat. The water consequently heats up, evaporating into steam. These water particles move further apart, causing the gas to expand until it pushes outwards on the fuel chamber. The inside pressure forces the gas outwards at a high velocity from the nozzle of the thruster, producing thrust. This process is shown in three stages below:

Alternatively, electric propulsion systems use electric and magnetic processes to shoot fuel out of a rocket, thus producing thrust. One of the simplest forms of electric spacecraft propulsion is a pulsed plasma thruster (PPT), otherwise known as a plasma jet engine. In the engine chamber, propellant (normally a solid) is converted into plasma (a gas cloud, filled with charged particles). On either side of the chamber are two electrically-charged plates, one positive, the other negative (a bit like either end of a battery). This gas cloud lies in between them. As the plasma’s particles are charged and able to move around, they are able to act as a bridge between the two charged plates, completing the circuit, like a wire connecting the two sides of the battery together. A complete circuit allows charged electrons to flow. This flow (and its consequent magnetic effects) results in our plasma being accelerated out of the PPT exhaust, at an incredibly high velocity (like this). The ‘pulse’ in PPT comes from the time taken to recharge, following each burst of propulsion (however, these pulses occur in very quick succession, so our spaceship’s movement is smooth, not jolty). Controlling our PPT allows us to control speed. This propels the spacecraft forward through space.

Changing Direction

That’s speed sorted – but how do we change direction? For us to control this, we have to control the orientation of the spaceship – this is what our spaceship’s attitude control system deals with. Attitude manoeuvres, sometimes known as roll/pitch/yaw manoeuvres (as outlined in the diagram below), involve making precise, fine adjustments to the direction a spaceship faces. 

This is achieved through use of smaller thrusters (known as vernier thrusters), which are strategically positioned around the aircraft, to exert the desirable level of torque (or spinning power) when in use (also visible in the diagram below). Some combination of roll, pitch and yaw manoeuvres will allow us to rotate our spaceship into any desired position. 

To power our vernier thrusters, we can use a chemical called hydrazine. We use this chemical as it is extremely reactive – it’s so reactive, it spontaneously sets itself alight when it comes into contact with certain chemicals! This makes it incredibly useful – it can release a large amount of energy without us having to heat our fuel to a high temperature, saving a lot of energy/fuel, whilst still providing the desired thrust for attitude manoeuvres. (SpaceX uses hydrazine in some of their thruster designs, for this reason). If we wanted to change orientation, we would input our desired change into the spaceship’s computer. Our computer would then control the firing of specific vernier thrusters at specific intensities (kept in-sync using special computer algorithms), and the spaceship would rotate accordingly, enabling us to make fine adjustments to the direction a spaceship faces.

Examples of Manoeuvres

We can now fully control our spaceship’s flight path – we can vary speed and direction. So what can we do with this? Here are two advanced, frequently used manoeuvres, which can help deal with changes in the flight path of a spaceship:

  • Trajectory Control Manoeuvers (TCMs) are used to adjust the flight path (pre-planned spaceship journey) of a space mission. They are conducted after or before a ship reaches an important milestone of its mission, like reaching the orbit of a planet. This is an important measure to take, as these precise adjustments make up for the small errors that add up over a spaceship’s journey, ensuring that our spaceship will stay on track in its path to Halley’s comet. Our attitude control systems are critical to TCMs.
  • A larger form of a TCM is a Deep Space Manoeuver (DSM). These manoeuvres (changes in direction) are controlled by the control systems mentioned earlier, only the manoeuvres are generally much bigger (opposed to the small adjustments undergone in TCMs).

More complex manoeuvres can be used to change how and at what speed our spaceship orbits a planet or outer space body. These manoeuvres take into account the impact of gravity on the spaceship. This set of manoeuvres (known as orbital manoeuvres) requires a strong understanding of a field of physics called orbital mechanics, but like TCMs and DSMs, fundamentally involve the same primary propulsion and attitude control systems that we previously mentioned.


Quick Fixes to Upgrade Your Submission!

Here are two key tips for you to unlock the full potential of your designs.

Written by Sung Soo Moon, Galactic Challenge Volunteer

Illustrated by Saffron Zainchkovskaya, Galactic Challenge Volunteer 

Are all your diagrams clearly labelled with dimensions and descriptions?

The world doesn’t run on wishy washy guesswork. When designing missions for interplanetary space travel, accuracy and precision are key for successful completion. With the Rescue on the Comet, the stakes are the highest imaginable since human lives are in your hands.

Describe your diagrams so people know what they’re looking at! We want to see how you communicate your vision and convey your ideas visually in a clear and concise manner. In real engineering situations, it is important that the thousands of people working on a project are all clear in your overall objective. It’s your job as the designer to remove all uncertainty in the design. If you’ve never seen it before, would you be able to tell what it is?

When you’re designing something, you will always have a sense of scale in your head that you want to convey to the viewer, so they too will understand your vision for the designs. Think about this clock you might have designed:

Who’s the clock for? How big is it? 5cm? 5m? 50m? 50km?

Now we need some dimensions and units. It provides a sense of scale to the viewer. Dimensions and units are crucial in any diagram; you don’t want to make a $125 million mistake like our friends at NASA once did.

Three clocks at different scales: an alarm clock (left), a larger clock (centre), and the interior of a really big clock with huge cogs (right). 

Additionally, it’s good to consider why a thing is a certain size. What if it were slightly smaller or larger, how would it be affected? In general, to blast things into space, we’d ideally like them to be as light and small as possible. In addition to this, smaller things usually are cheaper to make since it needs a smaller amount of the raw materials. To post a letter to Mars and back would cost a staggering £11,602.25, so every gram you want rocketed into space must be justified.

On the other hand, think about how practical and useful your designs can be. A space suit that only has 15 minutes of oxygen will be difficult to use. Keep in mind that accidents and emergencies can happen unexpectedly, and good designs will reduces the chances of different catastrophic situations outside of the user’s control.

Below is an example of the clock, labelled with descriptions and dimensions with units:

Make sure you give lengths for all three dimensions, as well as any extra measurements you think are relevant. Give a short, clear description of the feature so that the reader is clear in what you have designed.

Is your science referenced?

Any facts, figures and images you use in your submission should be referenced appropriately by providing sources. For us to judge your submission, references are helpful to check the science and your understanding of it. For a more general setting, the reader can look up your sources if they want to find out more about this particular topic.

Importantly, any bold claims must be backed up by legitimate scientific evidence! This does not mean you cannot be creative and inventive with your designs. We are looking at what might be plausible for the year 2061, so if you can find evidence of how your designs might work and how current technology will advance to make that happen, include it in your submission.

Referencing doesn’t necessarily mean scientific journal articles, and we don’t expect you to use them. Not everyone has a master’s in physics. Any reliable website, magazine, book or video can contain useful information you might want to use to support your designs. Wikipedia can be a useful tool, but shouldn’t ever be used as a reference because anyone can edit it at any time. You should provide a list of sources you use and refer to them where you use the information.

Make sure you can easily re-find sources from your research. You never know when you’ll need it again!

How We Judge the Digital Competition

What actually happens after you upload your entry? How are the awards determined? Take a look behind the scenes to see what happens during the judging process.

by Aadil Kara, Galactic Challenge Chair

The deadline to enter Mission IV of the Galactic Challenge is 30th June. After everyone has uploaded their entries, we will spend the next few weeks judging all the entries and choosing the winners.

If you are reading this, you might be interested in how we actually do that. Let us take a look behind the curtain, and see what happens during the judging process!

What happens to my entry after I upload it?

We start by looking through all the entries – every single one.

This is a quick check to make sure everything is in order. We check for corrupted and broken files. Sometimes people send us the wrong files by mistake, so we check for those too.

(If you’re wondering, some of the things entered over the last year include: a screenshot of our own website; some unrelated geography homework; and the music video for the 1987 Rick Astley song Never Gonna Give You Up. None of them won any awards.)

We then pass the remaining entries over to the judging panel. To make this as fair as possible, all the entries are anonymised.

The judges don’t know your names or the school you attend. They only see:

  • the name of your entry
  • the number of people in your team
  • your school years and age group.

How are the entries judged?

The judges have experience in science, space and education. To make it fairer, your entry will be judged by a pair of judges working together. 

There are six things we look at in each entry.

  • Three of these are the different tasks (they are labelled 1 to 3 on the website)
  • The other three look at the overall quality of the entry (we call them Science, Creativity and Presentation)

How can you get a high score? Here is a free hint: notice that each of the tasks has a blue box with a “Tip”. Those tips exactly match what the judges are looking for. Your entry will qualify for an award just by following those tips.

You can get even better awards by exceeding them!

How are awards chosen?

If the judges think that your entry achieves everything in the blue boxes, it will qualify for an award.

The entries are ranked using the scores given by the judging panel. Entries that qualify are given Bronze, Silver and Gold Awards.

The Special Awards are a little different. There are seven Special Awards:

  • Best of Key Stage 2 (Individual)
  • Best of Key Stage 2 (Group)
  • Best of Key Stage 3 (Individual)
  • Best of Key Stage 3 (Group)
  • The Science Award
  • The Creativity Award
  • The Presentation Award

At the end of the process the whole panel meets to select the final winners of these Special Awards.

What can I do to get an award?

Here are some ideas of what you can do:

  • Read the challenge information carefully.
    Your entry will qualify for an award just by following the tips in the blue boxes. You can get even better awards by exceeding those tips.
  • Check the rules of the competition.
    Importantly, keep to the page limit of four A4 pages. We do this to make it fair for everyone. If your entry is longer than this, the judges only consider the first four pages, so make sure all your best work is there.
  • Think about your entry layout and presentation
    The judges will score your entry highly if they can read it easily. Use headings to break up text. If you are writing on paper, make sure that the photograph or scan is clear and not blurry!
  • And finally, read the other articles in this collection!
    There is more to come in the next few weeks, with more top tips to improve your entry. If you have registered, you will get a weekly email about new articles.