The CBL framework and the Mars Challenge application
This challenge-based learning definition connects an open question with investigation, action and reflection. In a university context, applying the framework calls for evidence-informed decisions and revision of the work, beyond completing a one-off activity. Explore the university context in ORIGINALS.
The Challenge Based Learning framework has three interconnected phases: Engage, Investigate and Act, supported by documentation, reflection and sharing. The Mars Challenge journey described in this article is a specific application; its twelve phases do not replace the reference CBL framework.
An open question does not create learning by itself. It creates uncertainty. Challenge-Based Learning turns that uncertainty into a structured need to investigate, connect knowledge, make decisions, build, receive feedback and rethink.
The short answer
Challenge-Based Learning (CBL) organises learning around a problem whose answer has not been predetermined for the learner. Rather than receiving every relevant piece of knowledge before applying it, participants discover during the challenge what they already know, what they need to investigate, whose knowledge they need and which decisions must be made. The open question creates a need to learn; the learning design turns that need into inquiry, collaboration, prototyping, feedback, revision and reflection. Openness therefore does not mean lack of structure. The answer remains open while the process is deliberately designed. In Mars Challenge, this principle is operationalised through a twelve-phase journey and mentors who support the process without solving the challenge for participants.
Example formative assessment rubric for challenge-based learning
This rubric is an editorial proposal for discussing the learning process. It is not an official Mars Challenge edition rubric, a psychometric scale or a validated instrument. Official criteria and edition rules take precedence.
Before starting, teachers and students can adapt descriptors to their context, accessibility needs and curriculum goals. Review can take place during the work through self-assessment, peer feedback and teacher support.
A polished presentation is not enough to assign a level: look for process records and examples the student can explain. When evidence is missing, record “not yet observed” rather than infer a capability. Do not sum these levels as a validated measure of Real-Life Readiness.
Criterion and observable evidence
Initial
Developing
Substantiated
Investigate · questions, sources and records
Makes claims without identifying their source.
Identifies sources and answers some questions.
Compares sources, explains limitations and revises conclusions.
Decide · alternatives and rationale
Selects a solution without explaining why.
Compares alternatives using one criterion.
Justifies decisions with criteria, evidence and consequences.
Test · prototype, observations and revision
Describes an idea without test records.
Tests one aspect and collects observations.
Explains what the test supports and what needs to change.
Collaborate · contributions and shared decisions
Cannot identify contributions and agreements.
Records contributions and distributes responsibilities.
Shows how different perspectives changed decisions.
Reflect · learning, limitations and AI use
Reports the result without examining the process.
Identifies learning and operations delegated to AI, if used.
Explains what was checked, what was learned and what would change.
Hypothetical example: a team proposes reducing water waste at school. The prototype design is a product; comparing measurements, explaining choices and revising tests provides process records. These records support formative feedback without establishing lasting impact or causality.
Education is exceptionally good at organising knowledge.
Reality is not.
A course can separate engineering from psychology, economics from ecology or communication from science.
A real problem cannot be relied upon to respect those boundaries.
It also does not announce which chapter should be consulted.
This creates a gap between acquiring knowledge and knowing how to mobilise it.
Challenge-Based Learning brings part of that uncertainty into the learning environment.
Mars Challenge is explicitly structured as an international challenge-based learning programme in which multidisciplinary teams develop solutions while educators act as mentors rather than owners of the answer.
The purpose is not simply to make learning more active.
Activity is easy to generate.
The deeper purpose is to change the relationship between knowledge and the learner.
Knowledge stops being only something assigned in advance.
It also becomes something the learner must seek because the problem has made it necessary.
What Challenge-Based Learning actually means
Within the Mars Challenge model, CBL sits at the centre of a broader pedagogical architecture that also includes Project-Based Learning, experiential learning, applied research, STEAM+, formative assessment and Human Learning.
Its core mechanism can be stated simply:
the challenge organises the learning without predetermining the answer.
That makes CBL different from merely giving students a difficult assignment.
A challenge becomes educationally meaningful when learners have to determine:
what the problem really is;
what they already know;
what they do not yet understand;
which evidence they need;
whose perspective is missing;
which constraints matter;
which alternatives are possible;
what they are willing to choose;
how to make the idea visible;
how to respond when others question it;
and what they have learned after the process changes their original thinking.
A challenge is therefore not defined only by its topic.
Its pedagogy lies in the journey it creates.
From open question to learning
Open question
Need to know
Inquiry
Connection
Decision
Action
Feedback
Iteration
Reflection
Transfer
The open question creates authorship
In a closed exercise, the destination is known.
The student is evaluated on whether they can reach it.
In an open challenge, quality standards can still be clear, but there is no single hidden solution that participants are expected to reproduce.
This creates room for meaningful choice.
Learners must interpret the problem.
Choose priorities.
Decide what to investigate.
Reject some ideas.
Defend others.
Explain why one piece of evidence deserves more confidence than another.
And eventually take ownership of a response.
This is where an open question begins to connect with Agency.
If every meaningful choice has already been made, the learner may perform the task successfully without actually authoring the solution.
Yet openness cannot be unlimited.
Time, evidence, physical reality, rules and resources create boundaries.
Those constraints give decisions weight.
Open answer, structured process
The answer remains open; inquiry, decision-making and reflection follow a structured journey.
A challenge creates a need to know
One of the most powerful moments in challenge-based learning occurs when a team discovers:
we cannot move forward until we understand this.
That sentence changes why learning happens.
Research is no longer only an assignment.
Knowledge becomes a requirement for progress.
A case documented in the Mars Challenge Participant Guide illustrates the pattern. A team initially developed a water-purification direction that already existed. After that dead end, members returned to an apparently unrelated observation from a participant with baking experience: fungi. Further research into radiotrophic fungi opened a new direction for the project.
The challenge did not hand them the relevant knowledge.
It created conditions in which they had to recognise and investigate it.
That is a central shift.
The question “What do I have to study?” becomes:
“What do we need to understand in order to continue?”
Inquiry turns curiosity into usable knowledge
An interesting question can provoke curiosity.
CBL must take the next step.
It requires inquiry disciplined enough to affect a decision.
Learners need to ask whether information is credible, relevant and sufficient.
They need to distinguish evidence from assumption.
They may discover that a proposed solution already exists.
They may find that the apparent problem is only a symptom.
They may realise that the evidence contradicts their preferred idea.
Research therefore has an operational function.
It changes what the team can responsibly do next.
This is why applied research matters within a challenge.
The objective is not to accumulate information.
It is to improve the quality of the next decision.
Open answers require structured processes
A paradox sits at the centre of good CBL:
the more open the answer, the more valuable a well-designed process can become.
Without structure, confident participants may jump directly to the first idea.
Others may not know where to begin.
Mars Challenge addresses this through a twelve-phase sequence:
strengths → roles → idea dialogue → empathy → 5 Whys → canvas → prototyping → Return to Earth → storytelling → evaluation and questions → refinement → final presentation.
The methodology does not tell participants which solution to produce.
It directs attention at different moments.
Who are we?
What is the problem?
Why does it exist?
For whom does it matter?
What can we propose?
How does it work?
Why is it valuable?
What does the evidence challenge?
What should change?
This distinction is fundamental:
structure the journey; do not pre-write the destination.
Collaboration makes knowledge cross boundaries
Open challenges rapidly reveal that no single participant knows everything required.
This turns collaboration into more than task distribution.
Different knowledge has to connect.
Mars Challenge teams are expected to include multiple disciplines, and mentors are specifically instructed not to design the project or make decisions on behalf of the learners.
This forces translation.
An engineer has to explain something to a communicator.
A designer may expose a usability problem invisible to a technical specialist.
Someone from psychology may identify a behaviour assumption.
A business student may question viability.
The learning is partly located in those encounters.
Students do not only acquire more information.
They discover the limits and uses of their own knowledge.
Mentors protect the quality of the process
CBL changes teaching, but it does not remove the teacher.
A mentor who gives the answer every time uncertainty appears closes the challenge.
A mentor who provides no support at all mistakes autonomy for abandonment.
The Mars Challenge implementation model positions the mentor between those extremes.
Mentors accompany the process, facilitate the methodology, support organisation and help create clarity. They are explicitly not supposed to solve the challenge, provide the answer or direct team decisions.
This makes questioning one of the mentor's most important tools.
What evidence supports that?
Whose problem is this?
What are you assuming?
What would falsify the idea?
What happens when this part fails?
Why did you choose this alternative?
The educator still protects rigour.
But rigour is created by improving the learner's thinking rather than replacing it.
Prototyping makes thinking visible
Ideas are forgiving while they remain abstract.
Prototypes are less polite.
The moment a solution has to be drawn, modelled or demonstrated, hidden assumptions become visible.
How does it work?
What happens first?
What is connected to what?
Who uses it?
What has not yet been resolved?
The Mars Challenge Participant Guide describes the prototype as a representation that does not need to be perfect; it needs to make the solution understandable. Earlier sketches and iterations are also documented because the process matters alongside the final result.
Prototyping is therefore not merely production.
It is a thinking technology.
It turns an internal hypothesis into something that can be questioned.
Feedback turns doing into iteration
If a challenge ends with the first solution, learners can mistake initial confidence for quality.
Feedback interrupts that.
Mars Challenge allows teams to return to previous phases and modify their work. A later phase is explicitly devoted to refining the project in response to feedback before final evaluation.
The learner discovers that a first answer is not a verdict.
It is a testable position.
This is one of the reasons failure can become pedagogically productive.
Failure alone teaches nothing automatically.
Failure plus feedback, analysis and revision can.
Reflection turns experience into learning
Doing is not sufficient either.
People can be busy without becoming wiser.
Experience has to be interpreted.
Learners need to make explicit:
what they believed initially;
what evidence changed their view;
which idea was abandoned;
what failed;
what feedback mattered;
what they understand now that they did not understand before.
Mars Challenge's Concept Document records additional research, abandoned ideas, feedback, modifications and what the team learned.
This reflective layer matters because it separates two outputs:
the solution produced by the team
and
the learning produced in the team.
A challenge-based methodology should be interested in both.
Assessment tells learners what really matters
Assessment is not neutral.
It signals what the learning system values.
If only the final product is rewarded, learners can reasonably conclude that the process is disposable.
Mars Challenge's evaluation framework includes impact, creativity, design, level of development, learning and validation, relevance and viability, technical innovation, communication and Return to Earth.
This allows different solutions to be evaluated without pretending that all responses are equally strong.
The answer can remain open.
Quality can still have standards.
That is an important design principle for CBL.
How an open question becomes learning
The mechanism can now be stated as a complete sequence.
1. OPEN QUESTION
A meaningful problem exists without a predetermined learner answer.
2. NEED TO KNOW
Progress exposes a gap in current understanding.
3. INQUIRY
Learners investigate because knowledge is required for the next move.
4. CONNECTION
Different disciplines and perspectives become relevant.
5. JUDGEMENT
Evidence, constraints and trade-offs require choices.
6. ACTION
A hypothesis becomes a proposal, intervention or prototype.
7. FEEDBACK
Reality, peers, users, mentors or evaluators push back.
8. ITERATION
The first answer is revised.
9. REFLECTION
Learners identify what changed in their understanding.
10. TRANSFER
They recognise what can — and cannot — travel into another context.
The question does not contain the learning.
It creates the conditions that make learning necessary.
The process converts necessity into development.
What Challenge-Based Learning is not
CBL is not automatically a hackathon.
It is not simply group work.
It is not gamification.
It is not a prototype competition.
It is not unstructured discovery.
It is not asking learners to solve impossibly large world problems.
It is not removing subject knowledge.
It is not removing teachers.
And it is not always the right method for every learning objective.
Some knowledge is efficiently built through direct instruction, guided practice, reading, demonstration or other pedagogical approaches.
Challenge-Based Learning becomes especially valuable when the objective is not only to possess knowledge, but to mobilise it under conditions where the next step is not fully specified.
What the evidence says
The supplied Mars Challenge materials show alignment between pedagogical intent, participant experience and assessment design.
The programme identifies challenge-based learning as its central approach; uses a structured multi-phase journey; requires participants to research and prototype; allows revision after feedback; protects participant authorship through the mentor role; and assesses learning and validation alongside solution quality.
This is sufficient to describe the Mars Challenge implementation model.
It is not sufficient to claim that CBL is universally superior to every alternative pedagogy or to quantify long-term causal outcomes. Those claims would require additional comparative research.
Mars Challenge twelve-phase journey
Strengths
Roles
Ideas
Empathy
5 Whys
Canvas
Prototype
Earth-Back
Storytelling
Assessment
Improvement
Presentation
What we observe at Mars Challenge
Documented field cases illustrate how the challenge can change the function of knowledge.
In the radiotrophic fungi case, knowledge that initially appeared irrelevant became actionable after another direction failed and the team was forced to investigate again.
A multidisciplinary team from Portugal discovered that animation, psychology, communication and design could contribute to an aerospace context that participants had previously perceived as technically closed. Educators in Colombia and Spain documented students seeking and mobilising knowledge because the challenge required it.
These are first-party observations rather than controlled experiments.
Their importance is explanatory:
the challenge can shift knowledge from something assigned by the curriculum to something demanded by the situation.
What this means for educators and institutions
Designing Challenge-Based Learning means designing more than a compelling prompt.
It means designing the conditions around the prompt.
A useful design review therefore asks:
Is the question genuinely open?
Can learners make consequential choices?
Does the problem create a real need for inquiry?
Will multiple forms of knowledge matter?
Are there useful constraints?
Can thinking become visible through a prototype or other output?
Will learners receive feedback before the process ends?
Can they revise?
Will they reflect on what changed?
Does assessment recognise process as well as product?
Can educators support the journey without becoming the owners of the answer?
When these conditions align, an open question becomes more than an engaging classroom device.
It becomes an infrastructure through which knowledge has to move.
Challenge-based learning example: food waste at school
Hypothetical scenario for educators: how can we reduce food waste at school without compromising students’ nutrition? This example illustrates Challenge-Based Learning; it does not describe a Mars Challenge project or observed results.
The school community helps define the problem. Students choose what to investigate and justify their decisions; the teacher facilitates the process. Any observation or trial requires school permission and support from the team responsible for food provision, without collecting individual data.
The table shows one possible pathway. Phases can be revisited when an observation changes the question. Documentation and reflection continue throughout. The first solution is not assumed to work.
Phase
Possible action
Student decision
Record to collect
Engage
Listen to the catering team and identify an observable form of waste.
Choose a specific question and whose perspective is needed.
Question, scope, permission and perspectives consulted.
Investigate
Observe surplus food over comparable periods and consult sources on causes and food safety.
Distinguish surplus from assumed causes; compare two alternatives.
Aggregate records, sources, uncertainties and comparison criteria.
Act
With permission, trial a low-risk alternative, such as communication about portion choices.
Define what to observe, review the trial and decide whether to keep, adapt or abandon the proposal.
Prototype, trial conditions, observations and reasons for revision.
Product: a proposal or prototype. Process evidence: questions, sources, decisions and revisions. A short trial does not establish lasting impact or causality. Without authorised implementation and observations, report only a proposal. The formative rubric on this page can support feedback without replacing official criteria.
Is Challenge-Based Learning the same as Project-Based Learning?
Not within the Mars Challenge pedagogical architecture. Challenge-Based Learning is positioned as the central approach, with Project-Based Learning as a complementary one. The challenge organises the open problem and decisions; a project can be the vehicle through which learners investigate, build and communicate their response.
Does every challenge need to solve a real-world problem completely?
No. Authenticity does not require pretending students can permanently solve enormous global problems. They can address a credible part of a problem, investigate it seriously, propose an intervention, build a prototype and learn from the limits of their response.
How do teachers stop students from learning incorrect information?
Autonomy does not remove standards of evidence. Educators can question sources, request justification, identify contradictions and help learners recognise what needs verification. The distinction is that they protect the quality of the reasoning without replacing the learner's decision.
Can CBL be used in every subject?
Potentially across many domains, but that does not mean every lesson should become a challenge. CBL is particularly useful when learners need to mobilise knowledge, integrate perspectives, make decisions and respond to an open situation.
How can different solutions be assessed fairly?
By evaluating common quality dimensions rather than requiring identical answers. Evidence, reasoning, creativity, design quality, viability, learning, communication and response to feedback can all be assessed across different proposed solutions.
What happens when a prototype fails?
Failure can become useful evidence if learners can analyse it, receive feedback and revise. Failure without reflection is simply failure; failure embedded in an iterative process can expose assumptions and improve understanding.
What is the teacher's most important role?
To protect the quality of the learning conditions without taking ownership of the answer. This includes asking strong questions, maintaining evidence standards, giving feedback, identifying blind spots and helping learners continue when uncertainty becomes difficult.
References
Mars Challenge Participant Guide 2026 Mars Challenge, 2026.
Mars Challenge 2026 — Implementation Mars Challenge, 2026.
Module 5 — Team Management Mars Challenge, 2026.
Module 1 — Welcome and Purpose Mars Challenge, 2026.
Mars Challenge — Why It Is Different Mars Challenge, 2026.
How to choose a relevant challenge without promising impact before testing
A useful challenge does not have to be the planet’s largest problem. It needs to be understandable, investigable, connected with real people and open enough for alternatives. Relevance does not mean the team already knows the solution or can promise transformation.
Before proceeding, distinguish an observed problem, an investigable question, a proposal and demonstrated impact. This separation protects educational quality and prevents an intention from being presented as a result.
Question
Useful signal
Warning
Is it observable?
Situations, people or data are accessible.
A broad topic without context.
Is it investigable?
The team can ask questions and find sources.
A solution chosen before inquiry.
Does it allow alternatives?
More than one path is plausible.
A task with one hidden answer.
Can it be tested safely?
A bounded, ethical test is possible.
An impact promise without implementation.
Hypothetical example: “reduce waste at school” becomes investigable when the team defines where it occurs, whom it will consult, what it will measure and which small authorised test it can run.
Deepen: Explore how Challenge-Based Learning connects with Agency and Real-Life Readiness. Proof: See how the Mars Challenge twelve-phase journey turns an open challenge into a structured learning experience. Action: Discover how an institution can activate Mars Challenge.
This page remains the concept reference. Examples must be labelled as hypothetical, proposals or documented projects. Distinguish process, decisions, product and available evidence in assessment; an editorial guideline is not an edition’s official rubric. Explore the project archive and Mars Challenge methodology for the programme application without claiming ownership of the external framework.
Mars Challenge can use hackathon dynamics, but it is a broader learning system built around research, judgement, prototyping, feedback, responsibility and Earth-Back Thinking.
