Rocket, Satellite And Rocket In Orbit Refueling

By Arthur Brooks


When considering the space station, trips to Mars, the Moon, the Sun or other locations in our vast Universe, refueling rockets, satellites and spacecraft can often be a difficult task. For this reason, a depot which contains back up fuel has been placed near earth or other locations in space. While this is the case, there are new concepts being developed and designed with regards to in orbit refueling.

Without having fuel available in different areas of orbit, space exploration and travel will continue to be somewhat limited. Whereas, if these resources were made available in multiple locations in the infrastructure, all types of space exploration and travel would most likely become more prevalent. Different types of depots being necessary for different types of vehicles have prevented the concepts from reaching the design, development and deployment phase.

The various types of depots include on location, or a tanker which can deliver a single load to a spacecraft while at a specific location in orbit, then depart. In most concepts and designs, in-space fuel depots do not necessarily have to be positioned at or near a space station.

While several entities could benefit from these in-orbit refueling concepts, most are a long way from becoming a reality. Still, commercial companies such as Virgin, government agencies, NASA and commercial satellites would benefit in different ways. For one thing, all these and possibly other entities would save a great deal of time and money once the depots were deployed in different areas of orbit.

It is believed that if the depots were to come to pass, the satellites would participate with depots to transfer propellant so that the satellite could provide continued maneuvers while in orbit. Where some plans have been reviewed for replenishing the fuel satellites use, most recently in 2011, those plans have since been canceled.

As a fraction or all of a transfer stage fuel could be deployed, separately launched spacecraft with a payload or crew could cover a larger area or allow the use of a smaller launch vehicle. Whereas, with a tanker fill or LEO depot, the launch vehicle size could be reduced while increasing flight rates. In doing so, this would also cut the cost of a number of missions whether or not a crew is involved.

Concepts also suggest that depots could be placed behind the Moon to help reduce the costs of trips to the Moon or Mars. Whereas, others suggest that placing a depot in the orbit of Mars could also be useful with regards to reducing costs and making such missions more likely. For, only when crews can assure a safe return from Mars, the Moon or the Sun can such missions take place.

When it comes to spacecraft and rockets, 1/2 or more of the total mass is often fuel. Whereas, the larger a rocket, the more likely the engine will need to use a cryogenic fuel like liquid nitrogen or oxygen as an oxidizer due to the size and likely impulse. Still, the transfer of such materials must be done with caution due to the risk that the engine will experience boil off in the process.




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