Mars Rocket

 

 

The most detailed plan is the one described here by Space X. NASA have the more immediate lunar return as objective with a Mars mission perhaps in the 2030’s. As previously noted Space X is the private company controlled by Elon Musk, a visionary scientist and entrepreneur. Elon Musk is a wealthy man but Space X also part finances itself by supplying various space services and by raising outside finance. Although NASA has separate Mars plans they also co-operate with Space X

The declared objective of Musk is to make mankind an interplanetary species. He envisages a human colony on Mars. The timescale is flexible as the Mars rocket is in early development but the target is unmanned launch to Mars in 2026. Launch opportunities for low energy transfer occur approximately every 2 years and the earlier date of 2024 Musk now feels is probably too early.

The Space X Mars rocket has rather confusing nomenclature. The part which will travel to Mars is called Starship but this is the upper stage of a two stage launch vehicle also called Starship for both stages, The lower initial stage is known as Super heavy booster.

At the time of writing in Feb 21 Starship is conducting low altitude test flights and several Starships are under construction while the booster has never flown.

The total Starship as it will be launched is massive. It is 9m in diameter with booster stage 72m tall and upper ( Starship ) stage 30m tall. It is about the same height as the Saturn V Apollo lunar rocket but much larger and heavier. A guessestimate of the launch weight is 5000+ tons.

A new rocket engine has been developed called Raptor. This engine is designed to be as efficient as possible using so called full flow staged combustion. Essentially this means that the engine turbo pumps burn the main fuel and exhaust through the main engine bell. This contrasts with many earlier engines where the turbopump exhaust is dumped without much contribution to thrust. Starship will have 6 Raptor engines, the booster 28. 3 of the Starship engines will be optimised for best efficiency in the vacuum of space. The engines burn liquid methane as fuel and liquid oxygen as oxidiser.

This number of engines in the booster generates such intense sound that it will be launched from an offshore platform. This will be based on a heavily modified oil exploration platform. Early Starship test flights are from near the assembly factory at Boca Chica in Texas. They are unladen and use fewer engines.

The general plan is for the combination to launch from earth, the booster stage will burn all its fuel and then the Starship will fly on to orbit. At that stage Starship will have used almost all its fuel and will be refilled by a tanker Starship flying from Earth. Thus replenished Starship can accelerate to escape velocity and head to Mars. On reaching the very thin Martian atmosphere it will be slowed by first frictional heating , then a hypersonic parachute and finally by using its engines to land. On Mars it will refuel using the carbon dioxide atmosphere and water to produce fuel and oxygen from plant previously deposited by unmanned missions. Starship will then launch, fly back to earth, re-enter earths atmosphere and finally land under propulsive power.

The re-entry phases will be by the Starship horizontal with respect to the ground turning vertical in the final stage to allow propulsive landing. This is intended to give the highest drag on atmospheric re-entry. The bottom of the Starship will be covered by ceramic tiles to withstand the intense heat as the atmosphere is entered.

The Starship has a pressurised area at the top to accommodate up to 40 passengers. They will have individual cubicles in addition to common room, exercise area and viewing area.

While much of this is the plan which may well change as development proceeds Space X is a serious company with a good track record, Their workhorse Falcon 9 has something like 120 successful flights. It has been chosen by NASA along with its Dragon spacecraft to transport astronauts to the International Space Station. The Dragon sits atop the Falcon 9.

The Starship will be modified for lunar landing. The Moon would be too dusty for normal propulsive landing so the proposed modification has additional rockets mounted higher. Because of its size some sort of elevator is planned to deliver astronauts to the lunar surface from their position near the top of Starship.