Frequently Asked Questions

Why did you start developing Reentry – An Orbital Simulator?
I’m a big fan of flight simulators and especially the PMDG products. Being a space geek, I wanted to explore the Space Simulator market on the old NASA spaceships. I had been playing NASSP and Orbiter, and the Space Shuttle Missions Simulator 2007 for many years and I really like those products.

However, I wanted a 3D functional virtual cockpit, like the PMDG products has, while leveraging in-game systems that will help you learn these quickly while having fun. In addition, none of the simulator I know of covers Project Gemini with a functional virtual cockpit, so I decided to make one myself.


Early Access?
The Early Access is all about solving the required needs of the engine to be able to technically land on the Moon. Once I have the logical requirements of the engine and the general flow of the missions are working, I will continue to improve the simulator piece-by-piece by using physics to model the internal systems such as fluid dynamics, pressure, electricity, and so on. All of the internal systems are based on the logical descriptions of each system, carefully studies after the official manuals released by NASA. However, the goal is not to create something that exactly meets the same reports and papers released after the NASA missions. Things will be based on physics, but there will be differences because of this. The goal is to create something that will teach you how the spaceships were operated, that resembles real life, how you can fly them, while having fun doing it.


What platforms does it support?
Currently, the game is distributed through Steam and Windows Store. The game is Windows only during the initial Early Access release, however I’m looking into what’s required to support Linux and Mac too. The simulator will not be released for mobile devices such as iPad.


Is Reentry using realistic Orbital Mechanics to calculate trajectories?

All spacecrafts are using realistic orbital mechanics for real-time trajectory calculations. From the second the rocket is released from the launch tower, to the splashdown in the ocean, Newtonian based physics are used for all trajectories. The engines of the spacecrafts are using realistic parameters to thrust the rocket through the atmosphere where drag is calculated based on the Standard Atmosphere Model. 

The orbital mechanics are updated in real-time. This means that if you alter the trajectory, your path and orbit in space will change.

Due to the floating point limitations of Unity, a lot of positioning magic is needed when it comes to rendering the visual part of the physics system and I strive to overcome these issues as the game develops. If you notice any strange positioning of staged parts and so on, this is most likely due to these issues.


Are the internal spacecrafts systems realistic?
Every single system that I have implemented in Reentry has been modeled and programmed after the real manuals released by NASA. If you see a switch on the panel, and you touch it, it will most likely make an internal change in the spacecraft. The simulator is not sequence based, meaning you are in control of the spacecraft, the actions, and the outcome of the mission. Primary and backup systems are being modeled, and I wish to make this as close to the real thing as possible.


Are you modelling the differences between spacecrafts in a given program?
Both Mercury and Gemini had many minor (and some major) differences in the cockpit between each flight. For example, Gemini III did not use the Fuel Cells (batteries only). Mercury-Redstone 3 did not have the square window in front of the astronaut, but rather a tiny circular window on the side. Project Reentry does not aim to recreate all these differences. A generic cockpit based on the real manuals has been modeled for reach space program, and has the required features to support every mission that is to be developed in Reentry.


Are the internal systems physics-based?
A lot of the internal systems are already based on physics, but not all. As the game development progress, these systems will be improved one-by-one. Some systems has a simplified physical implementation that I aim to improve, but I rather have a simple physical implementation rather than a variable that just shows a value.


Does Reentry use the real AGC source code, or use Math Flow 3 for the OBC?

Not directly. I have not used the real source for the AGC, or the Math Flow 3 source for the OBC. I have based the logic on these though, and the AGC programs are using a lot of the same memory locations, logic, programs, verbs and nouns. The goal is that you should be able to use the real manual for the AGC to operate it. The OBC manual has also been used to make the implementation I have of it. But no, I haven’t written an emulator that compiles and run the real source code. The goal of this simulator is not to have everything exactly the same as it was in real life internally, but to have almost the same sequence and flow as the real astronauts had to perform, with similar values and instrument readings etc.


What languages does Reentry support?
The languages currently supported in Reentry is English. I plan to add more languages later. 


Is Reentry just a checklist game?
No, it is not. The switches on the panels are functional and will change an underlying system. You can follow checklists if you want, part of them, or just do your own thing. The game is not designed around having to first complete checklist X before the mission moves on. You are in complete control.


How much does Reentry – An Orbital Simulator cost?
20 usd through Steam and Windows Store


Where’s the pictures I take using the Photo Mode stored?
It’s stored in the application data folder located here: %appdata%\..\LocalLow\Wilhelmsen Studios\ReEntry
C:\Users\<your windows user>\AppData\LocalLow\Wilhelmsen Studios\ReEntry
Will the game have the Lunar Module?
Yes. It will. The initial Early Access will not have the virtual cockpit and interior of Lunar Lander, but it’s possible to dock and extract it, and undock from it. The initial Early Access version will focus on Mercury, Gemini and the Apollo Command Module. The interior and virtual cockpit of the Lunar Module is in development, and will be a free update during the Early Access period.


Can you land on the Moon?
Not yet. I’m currently working on TLI and the Lunar Module virtual cockpit. Once this is completed, I will start working on the Lunar landing itself. It will be a free update during Early Access.


Can I make my own missions?
Yes you can. Use the Mission Editors and the Campaign Maker to do this. Campaigns allows you to make your own space stories in Reentry. A campaign has a set of missions that needs to be completed in sequence, and the story will progress based on the missions you have completed.

A mission can either be part of a campaign, or be a single mission. A single mission can be a tutorial you wish to create, a mission that replicates a real mission such as Gemini VIII, or Apollo 8 and so on. Some missions will be out-of-the-box, and others will be made by the community.


What is your immediate roadmap for Reentry – An Orbital Simulator?
My roadmap after the initial Early Access release will be through frequent updates:

0) Fix the major launch issues and bugs
1) TLI
2) Lunar orbit
3) Basic Save State and Load State
4) Lunar Module virtual Cockpit
5) Landing on the Moon
6) Getting home
7) Better Moon
8) Continue working on the Command Module, as there are many systems that still needs attention


What about NASSP for Orbiter?
I’m a huge fan of the NASSP project (and Orbiter) and I really hope that Reentry – An Orbital Simulator can be a springboard for those who wish to take Apollo simulation to the next level. Reentry – An Orbital Simulator is simpler to get started with, and won’t be as realistic as NASSP. If you master the Apollo module in Reentry, it should be simple to get started with NASSP.


Will you implement the Russian space program?
I wish is to implement Vostok-1 after v1, but no promises.


What about the Space Shuttle?
The Space Shuttle might get a spot in Reentry once v1 is released.