If you’ve ever looked up information about rockets, chances are you’ve come across terms like **G** and **TWR**. These concepts may seem confusing at first, but we’ll explore them together to show that they are not as complicated as they might appear.

In this article, we will introduce these concepts by examining the liftoff of a rocket.

A rocket moves forward by expelling gas in the opposite direction of its intended path: if it needs to go upward, it expels gas downward. You can conduct a similar experiment at home with a simple balloon: inflate the balloon and seal it with the opening facing downward. When you release the opening, the air inside the balloon is pushed downward, causing the balloon to move upward. This principle is stated by **Newton’s third law**.^{1}

If the gas goes downward, it’s because a force is pushing it in that direction. According to Newton’s third law, this means an equal and opposite force is pushing the balloon in the opposite direction. In the case of a rocket, the engines push gas downward with a certain force, and this force is what we call the **thrust**^{23}** **of a rocket. Since thrust is a force, its unit in the International System is the **Newton**, denoted as **N**.^{4}

We’ve established that it’s the thrust provided by the engines that enables a rocket to move forward. However, what we want to determine is how fast it can take off. It’s crucial not to confuse throwing a ball with the operation of a rocket: in predicting the motion of a thrown ball, it’s the speed at which it leaves the hand that matters, while a rocket continues to be propelled after liftoff. Therefore, instead of focusing on the rocket’s speed, we are interested in its **acceleration**. Here, we will once again benefit from the work of Isaac Newton, specifically his second law, which provided the modern version of the **fundamental principle of dynamics**: the acceleration of an object is proportional to the sum of the forces acting on it and inversely proportional to its mass. In mathematical terms, this can be expressed as:

$$

\vec{a} = \frac{1}{m} \sum_i \vec{F}_i

$$

Where \(\vec{a}\) represents the acceleration of the rocket, \(m\) is its mass, and for every \(i\), \(\vec{F}_i\) denotes a force acting on the rocket.

We will now consider the moment when our rocket lifts off from the launch pad, which is right after losing contact with the ground. At this moment, two main forces act on the rocket^{5}: the weight of the rocket and its thrust. We assume that the rocket is perfectly vertical, so the weight and thrust are in the same direction but opposite in sense. Therefore, we can focus only on the vertical component of acceleration:

$$

a = \frac{1}{m} \left( F_p – m g \right)

$$

Where \(m\) is the mass of the rocket, \(a\) is its upward acceleration, \(F_p\) is the thrust upward, and \(g\) is the Earth’s gravity. We can also rewrite the equation in the following form :

\begin{equation}

a = g \left(\frac{F_p}{m g} – 1 \right)

\tag{AccG}\label{eq:acc_twr}

\end{equation}

Since we aim to lift off the rocket, the acceleration \(a\) must be strictly positive, meaning that the thrust \(F_p\) must be strictly greater than the weight \(m g\). In other words, their ratio must be strictly greater than \(1\) :

$$

\frac{F_p}{m g} \gt 1

$$

You’ve encountered this new term that is compared to the value 1? It’s the ratio of thrust to the weight of the rocket. We’ll call it the **Thrust-to-Weight Ratio**^{6}, often abbreviated as **TWR**. What’s interesting is that we can now compare rocket accelerations independently of their weight: if one rocket has a TWR twice as high as that of a second rocket, then the first one will accelerate twice as fast.

If we take a closer look at equation \eqref{eq:acc_twr}, we notice that the rocket’s acceleration at sea level is equal à \(g\) times the TWP minus \(1\). This last term is present because we focused on the rocket at sea level. However, if the rocket is in space, far from any gravitational attraction (in microgravity), then the acceleration would simply be equal to the TWR times \(g\). For a rocket with a TWR of \(2\), we would say that the rocket has an acceleration of \(2 g\).

It’s worth noting that a TWR of \(1\) does not allow the rocket to ascend from sea level. However, if there were no ground, it wouldn’t fall either; it would be in perfect balance. From the passengers’ perspective, a rocket with a TWR of \(1\) is equivalent to being on the surface of the Earth. This holds true regardless of whether the rocket is near the Earth or not.^{7}

This also means that if the TWR is \(2\), passengers will feel twice as heavy. This is not just a feeling: all mechanical structures of the equipment must also withstand this higher “apparent weight.” Therefore, there is often a desire to limit these additional mechanical stresses by restricting the TWR of spacecraft. To achieve this, it is essential to ensure that at any moment during the flight, the TWR (defined as the ratio of thrust to the weight one would feel at sea level on Earth) is below a certain threshold depending on the vehicle’s contents.

Let’s consider a very simple vehicle with a MK1-3 command pod, a Mk16-XL parachute, a TD-25 decoupler, a Rockomax X200-16 fuel tank, and a RE-I5 Skipper engine. Additionally, three Kerbonauts will board the command pod with all the necessary equipment. We will attempt to calculate the TWR (Thrust-to-Weight Ratio) at liftoff and then the theoretically maximum achievable TWR for the spacecraft. Let’s get started!

Before diving into the calculations, let’s first see what we need to determine this famous **TWR**. By definition, we’ll need to retrieve the engine’s **thrust **and the spacecraft’s **weight**.

For the **thrust**, the game or an online Wiki provides this information. We learn that the engine has a thrust of \(568.75\ \mathrm{kN}\) in an atmosphere with a pressure of \(1\ \mathrm{atm}\) (read as *one atmosphere*), corresponding to sea level on Earth or Kerbin. It’s also noted that its thrust is \(650\ \mathrm{kN}\) in a vacuum. Most rocket engines exhibit this property: they are more efficient in a vacuum than in an atmosphere, but we’ll discuss this another time.

For the weight of the spacecraft, we will only consider the gravitational acceleration at sea level on Kerbin, denoted as \(g = 9.81\ \mathrm{m/s^{2}}\). The next step is to determine the mass of the spacecraft. One could sum up the masses of the different parts of our rocket, including the mass of the Kerbonauts, but we will simply look at the mass indicated in the **Vehicle Assembly Building** (**VAB**) with the tank full and the tank empty:

Therefore, we read that the rocket has a mass of \(15.180\ \mathrm{t}\) or \(15,180\ \mathrm{kg}\) when the tank is full, and a mass of \(7.180\ \mathrm{t}\) or \(7,180\ \mathrm{kg}\) when the tank is empty. So, we now have everything we need to proceed with the calculations!

Let’s start by calculating the minimum TWR of the rocket when the engine is at full power. Since the TWR is defined as the ratio of thrust to weight, it is minimal when the thrust is at its lowest and the weight is at its highest, meaning the highest mass. This occurs with a thrust of \(568.75\ \mathrm{kN} = 568,750\ \mathrm{N}\) and a mass of \(15,180\ \mathrm{kg}\). Therefore, we obtain:

$$

\mathrm{RPP_{min}} = \frac{568,750}{15,180 \cdot 9.81} \approx 3.819

$$

One can indeed verify that the VAB indicates a TWR of \(3.82\), which is the rounded value of the one we have found.

It is now time to calculate the maximum TWR, which is reached when the thrust is at its maximum and the mass is at its minimum. This occurs with a thrust of \(650\ \mathrm{kN} = 650,000\ \mathrm{N}\) and a mass of \(7,180\ \mathrm{kg}\). Therefore, we obtain:

$$

\mathrm{RPP_{max}} = \frac{650,000}{7,180 \cdot 9.81} \approx 9.228

$$

As before, one can verify that the VAB indicates a TWR of \(9.23\) when the tank is nearly empty, and the engine is firing in a vacuum.

Indeed, one can conduct the experiment: on the launch pad, we observe that the displayed TWR is \(3.83\), while it reaches \(9.15\) when the tank is nearly empty. The discrepancies can be explained quite simply.

We can see that on the launch pad, the engine has an **ISP**^{8} of \(281\ \mathrm{s}\), while the Wiki indicates a sea level **ISP** of \(280\). We deduce that the engine on the launch pad has a slightly higher thrust than \(568.75\ \mathrm{kN}\).

The theoretical maximum TWR doesn’t seem to be reached, while the indicated **ISP** is. This is simply because the tank is not yet empty. Therefore, there must be around twenty kilograms of fuel left: I’ll let you do the calculation to determine it.

We’ve seen how to calculate the thrust-to-weight ratio of a rocket based on its mass and the maximum thrust of its engines. Now, let’s focus on setting the value of the maximum TWR reached by limiting the thrust of the engines. This can be useful when one aims to transport payloads that are not very resistant to high accelerations, such as tourists.

Let’s decide to allow a maximum TWR of \(5\), which corresponds to a maximum acceleration of \(5\ g\). We will then search for a value \(\alpha\) between \(0\) and \(1\), which will indicate the limit to be applied to the engines to ensure compliance with this restriction.

We aim to limit the maximum TWR, so we consider the minimum achievable mass, i.e., \(7,180\ \mathrm{kg}\), and the maximum thrust in a vacuum, i.e., \(650,000\ \mathrm{N}\). This leads to the equation:

$$

\mathrm{RPP_{max}} = 5 = \frac{650,000 \alpha}{7180 \cdot 9.81}

$$

We can deduce the equivalent equation by multiplying by the denominator and dividing by \(650,000\):

$$

\alpha = \frac{5 \cdot 7,180 \cdot 9.81}{650,000} \approx 0.5418

$$

Therefore, the engine must be limited to \(54 \%\) of its maximum power to ensure that the spacecraft will not experience thrust exceeding \(5\ g\) during its ascent. I’ll let you try this adjustment yourself and provide your tourists with safe journeys.

In this article, we have explored the basic principle of **thrust**, its connection to rocket **acceleration**, \(g\) as the unit of acceleration, and the concept of the **thrust-to-weight ratio**.

We have also seen that we can calculate this **TWR **ratio based on the engine thrust and the mass of the spacecraft. Furthermore, we explored how to determine the limit to apply to the engine thrust to ensure that the spacecraft will not accelerate too strongly.

I hope you enjoyed reading this article and that it inspires you to explore further with other articles available on the website.

- https://en.wikipedia.org/wiki/Newton%27s_laws_of_motion#Third_law
- You’ll have to get used to it: scientists don’t often have much imagination when it comes to giving names.
- https://en.wikipedia.org/wiki/Rocket_engine
- https://en.wikipedia.org/wiki/Newton_(unit)
- We neglect air friction for the sake of simplicity and because the rocket has an extremely low velocity, which implies friction forces that are negligible compared to other forces.
- You’ve been warned: no imagination for coming up with original names, but at least we know what we’re talking about.
- The Einstein equivalence principle: https://en.wikipedia.org/wiki/Equivalence_principle#The_Einstein_equivalence_principle
- I promise you: we will talk about it in a future article

- In 2017, Squad was acquired by Private Division.
- In 2019, a tantalizing trailer for KSP2 was released.
- In 2020, the COVID-19 pandemic (an argument perhaps overused to justify certain shortcomings, in my opinion).
- In February 2023, KSP2 finally launches amid complete chaos, requiring a powerhouse machine to run a bug-ridden experience and charging €50 for early access. It takes more than 6 months for the studio to announce a gameplay expansion by the end of the year.
- In March 2023, a wave of layoffs at Private Division raises concerns about the aftermath of the tumultuous launch.
- On December 19th, the arrival of science and exploration mode.

For my part, I devoted little time to KSP2 between version 0.1.0.0 and 0.2.0.0. This was due to my machine simply unable to meet the game’s technical requirements (1060 6GB). The graphics and lighting management were far from satisfactory in my eyes, compounded by a series of bugs that posed genuine obstacles to an enjoyable gaming experience. Additionally, the absence of essential features carried over from KSP1, such as a satisfactory ΔV calculation, the inability to precisely set maneuver nodes, and the lack of alarm management, also contributed to my reluctance. In a game like KSP, mission planning is crucial! Despite acquiring a new graphics card in May, I barely explored versions 0.1.1.0 to 0.1.5.0.

Well, what can I think about it? As you can imagine, there are both positives and negatives.

**Performances**. FINALLY! Feedback is remarkably unanimous: the game now demands much less power than before. My graphics card fan, which used to stay constantly active in certain views like the VAB or the map, can finally take a break. There still seems to be room for improvement, as the game hasn’t reached the caliber of titles like *Red Dead Redemption 2*, which isn’t that recent, or *Starfield*, known for pushing the most powerful machines to their limits. With my setup consisting of a 5600X and a 6700XT, I can finally play in 4k with settings mostly at maximum, even if it doesn’t necessarily maintain 60 fps, but that suits me perfectly.

**Stability**. With this version, one finds oneself playing for several hours without anxiously awaiting any manifestation of the Kraken at the slightest of our actions. Special mention to the almost disappearance of **wobbly rockets**.

**Graphics**. The lighting is softer, more diffuse, and the game loses that very metallic lighting that I found unappealing. The **Blackrack **touch is really felt, in the best sense of the term.

**The Tech Tree!** A true progression is finally introduced, sparking the desire to follow it and come back to the game to continue evolving. This novelty significantly transforms the perception of what the game has to offer.

The game still lacks a feature akin to **Precise Maneuver**. Planning and precisely adjusting a maneuver have become essential for accurate interplanetary transfers. Thanks to the community for providing a mod that fills this gap!

Several shortcomings prevent the optimization of spacecraft construction, and these are often complementary features:

- No priority management for fuel tank consumption,
- Unsatisfactory fuel tank consumption as soon as fuel lines are attached,
- Inability to delete parts in symmetry groups.

It is still very difficult to **create an asparagus build**, for example.

One can also note the blue reticle indicating the entry and exit points of Sphere of Influence changes. The idea is not bad, but as implemented, it overloads the display, with pixelated fonts that are hard to read and gradients or texture effects reminiscent, to their disadvantage, of EGA graphics from the 1980s.

The list of bugs tagged v0.2.0 is impressive. The ones that have had the most impact on my gameplay are as follows:

**Bug**

**Workaround**

The fairing does not protect its contents from heating

Options : disable heat

Parts heat up outside the atmosphere

Options : disable heat

Pods are not slowed down by the atmosphere

Cheat: Teleportation to a safe location

The ΔV calculation is sometimes incorrect in the VAB and during flight

None known to date

NavBall markers disrupt orbital rendezvous

None known to date

In particular, the DeltaV calculator does not know how to handle multiple engines distributed across several tanks as well as fuel lines.

As you can see, there are still many criticisms to be made regarding KSP2. The task remains enormous, and the developers will undoubtedly have a lot of work when they return from their holidays! However, after silently cursing the disastrous February release, exacerbated by poor communication, I finally want to adopt an optimistic stance. For the first time since the beginning of this adventure, I feel that the game is finally on the right track. What’s even better, this new version has prompted me to spend more time on the game since December 19th than I had devoted to its previous versions. Finally, I have been able to experience what one is entitled to expect from a game: playing it to the fullest! It is also remarkable to note that I have spent more time flying planes on Kerbin in KSP2 than during my entire period of activity in KSP1, a sign that the game is enjoyable!

When you spend hours fine-tuning a spacecraft in the VAB, it’s usually a good sign

Ultimately, this release marks a genuine embrace of the product by players, and I believe that this update, v0.2.0.0, has literally saved KSP2. Finally, a sign that the tide has turned favorably, within the KSC association, we are seriously starting to consider KSP2 as a platform conducive to the creation of exciting challenges!

]]>Let me tell you about this incredible weekend. Because this weekend was SpaceCon’23.

The story begins in a unique place, a timeless witness to the waves of elites who pass through its corridors: the École Polytechnique. Our heartfelt thanks go to the school, **AstronautiX **and its president, Aurélien Genin. We were able to use the Poincaré amphitheater for 3 days.

**But what did we do in this amphitheater?**

We prepared an incredible challenge in partnership with EURO2MOON. Many thanks to Bertrand Baratte, the event’s sponsor, and his incredibly versatile team, who touched on all areas with the aim of getting Europe back into the space race, and if possible to the moon. I’m sure that the themes addressed have raised a few consciousnesses.

We asked 18 talented teams to use their favorite tool, the Kerbal Space Program, to model the issues and challenges facing our space agencies today and in the near future.

**Kerbal Space Program (KSP)… What is this thing?**

It’s a space programme simulator which, although it looks like a fun game, embeds the whole corpus of the laws of gravity that govern our solar system. The funny rocket you have to launch will therefore be subject to the very real 3 laws of Newton, and all of a sudden. To get it into orbit, your rocket is going to start looking pretty realistic.

So realistic, in fact, that the Kerbal Space Challenge association runs courses in space mechanics using KSP as a teaching aid in top schools.

**So what were these prodigies asked to do?**

*“You have to demonstrate the usefulness of setting up a lunar base and/or a relay station as part of a “deep space” mission.”*

And it doesn’t stop there: to change perspectives and raise awareness of environmental considerations, we’ve turned the tables. Did you know that for a Falcon Nine, refuelling represents only 0.3 to 0.5% of the cost of the flight, whereas refuelling represents 70% of the flight’s carbon footprint?

They had 24 non-stop hours to model their solution and just 7 minutes to present it. The subject was revealed at the start of the test.

So we modified a version of **KSP** (thanks to Oscar ** [Harpercix]** Chevalier and Yann

The candidates were given the opportunity to present their projects, and several strategies were put forward. The aim was to be economical. But we expected realism. So, while we favour the reuse of systems, redundancy was expected when the system was unmanned. We had intelligent gateways that would refuel around the moon and bring the ergols close to Earth. Small, highly mobile automated ressources extraction systems to cover as large an area of the Moon as possible.

@Matt Lowne and @The Beardy Pinguin did us the great honour of taking part. In fact, they didn’t just take part, they won. They were followed by our talented space mechanics teachers Guillaume *[Dakitess]* Duchesne and Romain [RPfive05] POIRIER , who were hard to beat when it came to optimising interplanetary trajectories. Special mention must go to Stanislas Maximin and Whitney Jerosme, who didn’t quite follow the specifications but gave us fantastic drifts on Mars competition.

Beyond the good-natured atmosphere, this hackathon is above all an opportunity to bring together enthusiasts and professionals in the same field.

The professionals, Aline Decadi, the Ariane 6 specialist, and Raphael Chevrier, PhD of MaiaSpace, were the ones who judged the creative treasures and gave the challenge its unique touch.

All of this was made possible thanks to the support of HP Omen, who provided us with machines of extraordinary capacity. Faultless organisation by Ruben Di Battista, Pierre Cordesse, Alexandre Poirier, Leo, Alberto Remigi and Ekaterina Seltikova.

As well as the opportunity to present the association and its aims offered by Jeremy Sadet and Brigitte BAILLEUL from SPACE UP.

We can’t forget to mention Private Division, publisher of KSP, which always supports our side!

**Thank you all, you’ve set the bar so high! It will be difficult to find a new challenge as rich as this one.**

I would like to express our deep gratitude to all members of our association Kerbal Space Challenge. We have a wide range of missions in the fields of animation, teaching and event management, and every call is answered. Your dedication is a source of inspiration for all of us.

Oscar Chevalier Yann Mornet Thomas Bellier Emilien Jouvin Benoit Bataillou Stéphane Hodebert Guillaume Duchesne Romain Poirier Aurélien Genin

Together, we form a supportive community and we look forward to continuing to create memorable moments and reach new heights. Thank you for being valuable members of our association!

See you for the next Challenge!!

]]>You may find us on our Twitch Channel at 3pm for an interview with **Nicole Stott** , 5pm with Scott Manley , 7pm with **Alain Bataillou** and 9pm with **Jean-Loup Chrétien**.

The challenge finishes at 10am on Sunday with the participants’ presentations

Finally, the event finishes at 3:30pm after we announce the results! If you can’t come to see us, you can still watch us at https://www.twitch.tv/kerbalspacechallenge

]]>We will announce the exact date and more details soon, but rest assured, it will be open to everyone, including inexperienced players. So, don’t hesitate to sign up (especially if you plan to participate in the rest of **#SpaceCon23**).

In the meantime, you can watch the 2021 aftermovie and take note of he debriefing from the admins of Kerbal Space Challenge.

Similar to the inaugural edition in 2021, the challenge will take place alongside the **#SpaceCon23** organized by **SpaceCon**. It will utilize **KSP **developed by **Intercept Games** and will be sponsored by **OMEN HP France**. A big thank you to them!

After the *Bigger *challenge where the heaviest possible payload had to be put into orbit, the **Dresliveroo **challenge is to send a payload to the planet **Dres**, more exactly within the limits of a base specially installed there.

The payload is imposed, it’s up to you to build the ship that will move it. The mission starts once the ship is in waiting orbit around Kerbin, it ends when the payload is separated from its ship at the delivery site and the kerbals are safely in the base.

For this edition, your ingenuity will count as much, or even a little more than the usual criteria of mass and the lowest costs.

The rules of this challenges are depicted in the following PDF document (English).

]]>The practical applications are played on the Kerbal Space Program (KSP) platform. This game is an incredible pedagogical tool to understand many laws of physics, sometimes counter intuitive, to achieve a successful launch of a rocket.

KSP is both playful and realistic and allows future engineers to learn the future tools they will have to manipulate in their future career. Our association has made a specialty of teaching it in high schools.

When the influence at the booth was calmer (i.e. not often!) we were even able to push our young prodigies to perform a moon landing. It looks complicated, but it’s only an earth orbit that we extend a little further.

The success of this space seduction operation would not have been possible without HP Omen, which lent us 4 machines out of the ordinary and ensured a logistics with the cord.

**Configuration of OMEN 45 L**CPU : Ryzen 9 7900X

GPU : RTX 4070ti

RAM : 32 GB

STORAGE : 1Tb

With such engines, the young and greedy KSP2 could run smoothly with all sliders pushed up. Private Division, publisher of KSP, overwhelmed us with goodies for the event. Each little spaceman was able to leave with his sticker sheet!

Thanks to *Ruben Di Battista*, *Stéphane Hodebert* and *Romain Poirier* for a perfect animation of the booth !

Thanks to the SSF and *Antoine Bocquier* for the organization of such an event. I think we were at 5.000 people on the 2 days. These are so many European actors who meet to build our future in the stars.

**Meet KSC and SpaceCon in Paris in September for the SpaceCon’23!**

The aim was to provide students with a “ready-to-go” introduction to this playful and educational tool, enabling them to integrate it into their studies and have an additional resource to grasp the laws of orbital mechanics, mission design, and vehicle sizing. This workshop had also been conducted at the IPSA Toulouse campus, and we are proud to be able to continue this partnership!

These sessions, lasting just over 3 hours, allow us to guide newcomers who have never interacted with Kerbal Space Program #KSP before. We provide shared licenses in advance to facilitate exercises during the sessions. It’s only through practice that one can perceive the true potential of this tool. The agenda includes exploring interfaces, constructing a simple launcher, learning orbital insertion and the revered Gravity Turn, utilizing maneuver nodes to transition between orbits, and finally landing on the Mun for the more adventurous participants!

Each chapter starts with an expert presentation of the topic at hand, followed by a theoretical overview that helps students and teachers to understand the possible connection between real-world mathematics and KSP. Then comes an application exercise, each person working on their PC, with assistance from the session facilitators.

We extend our gratitude to the teaching team: *Naouel Kaci-Debiane, PhD*, and *Anica Lekic* from the communications department for this opportunity, which will be repeated this Thursday, 30/03. We hope to see as many students as possible, enthusiastic and passionate, in attendance.

Ariane 5 will soon hand over the reins for the Juice mission. So, wouldn’t this be the perfect time for a little challenge? Well congratulations, you have been assigned to manage the KJuice program for the Kerbal National Agency of Kerbin Institute (KNAKI).

**Search for Signs of Life**: It is believed that Laythe, Jool’s moon, has an ocean that could harbor life. A probe could search for signs of life by examining the moon’s surface and sampling its ocean.

**Study Geology**: Jool’s moons are among the most geologically active bodies in the Kerbol system, with features like active volcanoes and geysers on Vall. A probe could study these features to learn more about moon geology.

**KJuice Goal**: Understand the Kerbol system. Studying Jool’s moons can help us understand the formation and evolution of the Kerbol system. It is believed that these moons formed from the same disk of gas and dust that formed Jool, so they can provide clues about the conditions of the early solar system.

Place a probe in orbit

of each Jool’s Moon.

Design a system to send generic probes to map the moons of Jool. One probe for each moon, and a relay probe will orbit Jool in a heliosynchronous orbit (a polar orbit is accepted) to maintain constant contact with Kerbin.

This is a short mission, with a budget allocated for only one year. The 6 probes must arrive together or approximately together. The last probe must have left Kerbin’s sphere of influence before the first one arrives in the case of a staggered launch.

**1-** The launcher(s) must be fully assembled on Kerbin's surface and/or its orbit. You can imagine a massive carrier ship for the simultaneous launch of 6 small rockets.
**2-** When the first probe is captured by Jool, the last one must have left Kerbin's sphere of influence.
**3-** Devise a communication strategy to maintain contact with your program.
**4-** (Bonus) This mission pays homage to Ariane, a bonus will be awarded if the launcher's visual design resembles an Ariane 5.
**5-** The 6 probes must adhere to KNAKI's specifications:
**>** Defined as a probe (use the "Rename Vessel" function in the game).
**>** Weighs less than one ton.
**>** Not crewed.
**>** Has at least one solar panel or an RTG (Radioisotope Thermoelectric Generator).
**>** Has at least one battery, one antenna, and one sensor.

You must complete this mission with a stock version of KSP 1.12.5 or KSP 2 for the more daring. DLCs and mods, other than graphical mods, are not allowed to maintain fairness among all participants.

**-** The announced price does not match the price of the provided craft (KSP 1).
- The mass and deltaV values announced do not match the craft's values (KSP 2).
- You do not provide a screenshot with the 6 probes in the Joolian system.
- A crew member is killed during the mission.
- A mod and/or modified parts are used for the expedition.
- The files submitted to the jury are missing, unreadable, or corrupted.
- You refuse to demonstrate your mission to the jury within 2 weeks after being notified.

You can submit your proposal here: **https://forms.gle/Ne5ysHuCmrxZ3JBp6**

Don’t forget to join our Discord server: **https://discord.gg/33XaFRdCEY**

To be accepted, your submission must include:

**-** Your Name
- Your Email
- The name of your program
- The name of your team/organization, fictional or real
- The cost of your program (KSP 1)
- The weight and deltaV of your program (KSP 2)
- Narrate your achievements:
> A summary of your adventure on a maximum of 5 pages/slides or a video of up to 15 minutes. Exotic formats are accepted. You can propose a different format by email or on the dedicated challenge Discord channel.
> A view of your launcher(s) on the launch pad.
> A screenshot of your 6 probes around their respective celestial bodies in the Joolian system from the space center.
> The .craft (KSP 1) or .json (KSP 2) of your complete spacecraft. This will be tested on the latest stock versions of KSP 1 or 2.

You must provide the above elements in **a zip file** by email to: **contact@kerbalspacechallenge.fr**

Keep backups of key moments in your mission: launches, captures, injections, and orbit finalizations. You will need to replay these moments live in case of victory.

In the event of victory, you will be invited to replay your mission in a video conference with the jury before the official announcement of your victory and the review of the various elements constituting your submission. An oral presentation of your design choices and construction methods will also be requested. You must, of course, use the same craft as the one submitted. In case of disqualification, the next best proposal will be audited.

You can find the KSP wiki here: KSP Wiki Link Need clarification on a rule? Contact us on Discord or by email: **contact@kerbalspacechallenge.fr**

Good Luck & Fly Safe

KSC is an association promoting space exploration, especially through space exploration games, and Juno checks all the boxes. But what is Juno, you ask? Well, it’s a procedural space exploration game (both in terms of engines and tanks) that offers some additional features. Honestly, give it a try at least! For the occasion, Jundroo has graciously provided 5 keys, thanks to them!

Let’s talk about the challenge! Your mission, should you choose to accept it, is to circumnavigate Droo (the Earth over there) as quickly as possible.

Of course, this circumnavigation must be done at the equator level. Otherwise, there are no further restrictions. Do you want to build an airplane? A rocket? A race car? The last suggestion might not be the best, but do whatever you fancy!

Start by downloading the custom career

Then place it in `C:\Users\USERNAME\AppData\LocalLow\Jundroo\SimpleRockets 2\Career`

. Afterward, create a new career game by selecting **KSC**. Finally, accept the contract, and you’re good to go !

To submit, send a screenshot of the completion through the form. If you send multiple screenshots, the last one will be considered. You have until February 24th to participate!

This new game in the community comes with new channels in our Discord! Come visit or ask your questions!

]]>