Building Venus Rockets

This article will explain how to build a rocket that can go to Venus and possibly back. Building Venus rockets should be done after building building Mars rockets and Moon rockets. A tutorial for how to get to Venus can be found here.

## Rocket

The rocket is very similar to a Moon/Mars rocket, but with heat shields and less parachutes. For usual missions, it is recommended to have at least 2 or 3 stages for a rocket to land or explore Venus.

It is recommended a rocket to Venus would consist of at least three to five stages in a landing and return mission if refueling mid-mission is not considered.

### 1st and 2nd stages

These need to be powerful enough to send the entire rocket to low Earth orbit and start a trans–Venusian injection. The Titan/Hawk engine can be the first stage engine to lift up the entire rocket up to the Kármán Line, and Frontier engines or Valiant engines can bring the rocket to LEO. Boosters may be necessary if the rocket has a low thrust.

### 3rd stage

This stage and/or the previous stage will execute the transfer burn to Venus, alongside with deep space maneuvers if required, then a retrograde burn to enter Venus orbit and start aerobraking. Entering its atmosphere is the biggest challenge of this mission. It requires many heat shields. Venus's atmosphere is enough to destroy rockets passing through its atmosphere, with or without a heat shield. The rocket must go to orbit before landing to decrease velocity during entry, and this in turn can decrease the heating effects.

Landing on Venus is one of the most challenging steps because of the rough terrain. A rocket must land in a flat zone (e.g. Atalanta Planitia) and carry at least one parachute.

### 4th and 5th stages

Similar to the first two stages, the 4th and possibly parts of 5th stage will bring the rocket to the orbit. It might not be necessary to use heavy-lift engines like the Titan Engine as the remaining stage is much lighter than the entire rocket. The Hawk Engine will lift off the rocket off the ground, and the 5th stage will execute a trans-terrestrial injection, and land similarly to the Venus landing.

## Tips

### Refueling

It may be worthy to refuel the rocket's 2nd or later stages with a Helping Vehicle or a Space Station. This can increase the fuel margin for the later stages, improving the likelihood of mission success.

### Fine-tuning the trajectory

Fine-tuning the rocket's trajectory can ease the difficulty of visiting Venus.

### Aerodynamics

Both Earth and Venus have atmospheres (30 and 40 km respectively), have thick atmospheres (Venus's atmosphere is denser) and rather high gravitational acceleration (9.81 and 8.87 m/s^2 respectively), making it challenging to get to orbit. Improving the aerodynamics and increasing the TWR of the return stage of the rocket can ease the process.
Parachutes on earth will slow down a rocket to around 5 to 9 m/s, while on Venus it will slow down from 0.5 to 3 m/s, depending on weight.

#### Streamlining the rocket

Try making the rocket a stretched "A"-shaped, rather than "V", "H" or "I" shaped. This can reduce the aerodynamic drag, so that it is easier to reach orbit.

#### Increase aerodynamic effectiveness

Adding fairings to cover your lander or payload will reduce the rocket's drag. Triangular Nose cones can be used on boosters to improve aerodynamics and save fuel for the mission.

### Optimizing TWR

TWR is the Thrust-to-Weight-Ratio of a rocket. It is determined by (error) , where *`g`* is the gravitational constant of a planet; in this case, Earth or Venus. If the TWR is higher than 1.05, it can lift off of the ground. A higher TWR usually indicates the rocket can go further a one with a lower TWR.

It is quite difficult to increase the number of engines due to limited building space and aesthetics. Instead, it is simpler to opt for optimizing the weight. Find out any unnecessary parts in your rocket (e.g. extra structural parts) and remove them. This can reduce the workload of the engines.

### Other

* Bring more fuel than needed to allow recoveries from accidents or fails.
* Using parachutes instead of executing retrorocket burns to land can save fuel and the overall mission complexity, but increase mission time.
* Dump unnecessary weights to reduce fuel required. They include unused parts and empty stages.

## Gallery

The Muon 1A, a five stage smallsat launch vehicle can send probes to Venus.
## Real life rockets

Rockets that have launched or will launch probes to Venus.

* Molniya-M
* Atlas-Agena (Carried *Mariner 2* and 5)
* Proton-K/Blok-D (Carried Venera missions)
* Atlas-Centaur (*Pioneer Venus*)
* Space Shuttle (*Magellan* and *Galileo* (*Galileo* used a gravity assist of Venus)
* Titan IV (*Cassini* (Gravity assist of Venus))
* Soyuz-FG/Fregat (Carried *Venus Express*)
* H-IIA (Carried *Akatsuki*)
* Delta II *(MESSENGER*)
* GSLV (*Shukrayaan-1*)

## See also

* How to go to any celestial body in Spaceflight Simulator
* Getting to Venus
* Venus Return Mission