Non-Rocket Spacelaunch – Advantages and Difficulties of a Launch Loop
This is the second part to the article on the launch loop from the non-rocket spacelaunch series. A complete list of all the articles in this series can be seen at the end of this post. A schematic of a launch loop as imagined by Lofstrom. Advantages of launch loops Unlike conventional rockets, launch loops can have many launches per hour, independent of weather, and are not inherently polluting. Rockets create pollution such as nitrates in their exhausts due to high exhaust temperature, and can also create greenhouse gases depending on propellant choices. Launch loops require power in the form of electricity and as such it can be clean. For…
Non-Rocket Spacelaunch – Launch Loop
A launch loop (also known as a Lofstrom loop) is a proposed design for a very efficient non-rocket spacelaunch method. It is a much simpler concept than the space elevator, but still more complex than tether propulsion systems such as the rotovator. The launch loop concept was first described by Keith Lofstrom in November 1981 Reader’s Forum of the American Astronautical Society newsletter, and in the August 1982 L5 News. Another pioneer of the concept was Paul Birch. In 1982 he published a series of papers in the Journal of the British Interplanetary Society which described orbital rings and described a form of launch loop which he called Partial Orbital…
Non-Rocket Spacelaunch – Tether propulsion in fiction
This is the fourth and final part of the tether propulsion article of the non-rocket spacelaunch methods article series. This post will focus on references to the tether propulsion concept in fiction. The most prominent science fiction novels on the subject include: The Last Theorem is Arthur C. Clarke’s posthumously published novel which he co-wrote with Frederik Pohl. The novel describes the skyhook as a means of interplanetary travel rather than simply a means to reach orbit. It is used as a means of transport by athletes and delegates to the “first-ever lunar Olympics”. Another interesting novel is The Descent of Anansi published in 1982 by Steven Barnes and Larry…
Non-Rocket Spacelaunch – Tether propulsion safety issues
The use of tethers in space poses many challenges and safety issues. This third part to the tether propulsion article will focus on those issues. A lot of the challenges and safety issues of a space tether system are similar to those of a space elevator described in a previous article, but some are unique to the space tether concept.
Non-Rocket Spacelaunch – Tether satellite missions
This is the second part to the article about tether propulsion. It will focus on space missions that tested tethers in space. Gemini 11 mission: 1966 Gemini 11 mission with tether visible. Image credit: NASA. The first such mission took place in 1966. Gemini 11 deployed a 30m tether connecting it to the Agena target vehicle. It created a small amount of artificial gravity (0.00015 g) by spinning the two spacecraft. TSS-1 mission: 1992 The deployment of the TSS tethered satellite The TSS-1 (Tethered Satellite System-1) was a joint NASA-Italian Space Agency project. It was flown during STS-46 aboard the Space Shuttle Atlantis from July 31 to August 8, 1992.…
Non-Rocket Spacelaunch – Tether propulsion
Having finished writing about the space elevator, I am moving on to another spacelaunch method in this new article in the non-rocket spacelaunch series. Tether propulsion consists in using long, very strong cables (known as tethers) to change the velocity of spacecraft and payloads. The tethers may be used to initiate launch, complete launch, or alter the orbit of a spacecraft. This form of propulsion would be significantly less expensive than spaceflight using modern rocket engines. Artist’s conception of satellite with a tether. Image by NASA. How does it work? Tethers are kept straight by either rotating end for end, or by the difference in the strength of gravity over…
Non-Rocket Spacelaunch – Space Elevators in Fiction
This is the fourth and final part of the space elevator article of the non-rocket spacelaunch methods article series. This post will focus on references to the space elevator concept in fiction. The first mention of anything remotely similar to a space elevator was the beanstalk in the children’s fairy tale called Jack and the Beanstalk, published in 1807. In this story a plant grows up into the sky enabling Jack to climb it and see what’s up there. This is why the word “beanstalk” has been coined as another name for a space elevator. Now on to more serious literature: My all time favorite book series including a reference…
Non-Rocket Spacelaunch – Extraterrestrial Space Elevator Concepts
Earth is not the only planet that could have a space elevator. Variants of the basic space elevator design could also be built on other celestial bodies in the solar system. Most of those variants could fit into three categories…
Non-Rocket Spacelaunch – Space Elevator Safety Issues
The space elevator is a gigantic concept and as such it has many safety issues that would have to be resolved before construction begins. A space elevator would present a navigational hazard, both to aircraft and spacecraft.
Non-Rocket Spacelaunch – Space Elevator
Today I’m starting a new series of articles about non-rocket spacelaunch methods. Non-rocket spacelaunch is the idea of reaching outer space without the use of conventional chemical rockets, which is currently the only method in use. Why non-rocket spacelaunch? Because the current chemical rockets are really expensive. In order to further explore outer space and establish a permanent human presence in space we need more cost efficient spacelaunch methods. In fact, present-day launch costs are in the range of $10,000 to $25,000 per kilogram from Earth to low Earth orbit. This is much too expensive for any serious space colonization efforts. Therefore we need to move beyond conventional chemical rockets…
