Launching from Venus presents a unique set of challenges compared to launching from Earth, primarily due to the intense atmospheric pressure and, of course, Gravity On Venus Compared To Earth. While Venus is often called Earth’s twin, its surface conditions are drastically different, especially when considering space travel.
One of the most significant hurdles is the aerodynamic pressure, often referred to as “Max Q”. At a mere 10 kilometers above Venus’s surface, a speed of only 46 meters per second (around 100 mph) results in a Max Q of approximately 39.5 kPa. This is already comparable to or even exceeds the Max Q experienced by rockets launching from Earth, but at a much lower altitude and speed. This immense pressure at relatively low speeds means any ascent from Venus must be painstakingly slow in the initial phases to avoid structural damage to the launch vehicle.
This slow initial ascent directly combats gravity. Venus has about 90% of Earth’s gravity, meaning it’s not significantly less, but still a substantial force to overcome. Because of the slow climb through the dense lower atmosphere dictated by Max Q limits, a considerable amount of time is spent fighting against gravity before even beginning to angle towards orbit. This period of vertical ascent to escape the thickest part of the atmosphere results in significant gravity losses, demanding a much larger delta-v (change in velocity) to achieve orbit compared to a launch from Earth.
Estimates vary, but some calculations suggest that reaching Venusian orbit could require a delta-v as high as 27 km/s. While some simulations, under highly optimistic assumptions about engine performance in Venus’s dense atmosphere, have proposed lower figures around 15 km/s, the consensus leans towards a significantly higher delta-v requirement than for Earth.
In conclusion, while gravity on Venus compared to Earth is only slightly less, the overwhelmingly dense atmosphere creates extreme aerodynamic pressures at low altitudes. This necessitates a slow initial ascent, leading to substantial gravity losses and a far more challenging and delta-v intensive launch into orbit than from our home planet.
