Category Archives: Space Systems

History, Space Systems

The Skylab legacy

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Skylab, the first US space station, was launched 40 years ago from yesterday. Here’s a NASA video about the project:

Skylab’s May 14, 1973 launch into low-Earth orbit was the nation’s first foray into significant scientific research in microgravity. The three Skylab crews proved humans could live and work effectively for long durations in space. This NASA video recounts the history of the program and showcases Skylab’s legacy as a major stepping stone to the successful construction and operation of the International Space Station and future long-duration human missions to asteroids, Mars and other destinations.

Amateur/Student Satellite, Space Systems

ESTCube, now in orbit, to test E-Sail propulsion

The Estonian student Cubesat project ESTCube successfully reached orbit via a Vega rocket this week:

Paul Gilster writes about the E-sail propulsion concept, developed by Pekka Janhunen of Finland, which will be tested by ESTCube: To Ride the Solar Wind.

Rockets, Space Systems

Alternative fuel to hydrazine to be tested with NASA’s GPIM spacecraft

A US Air Force sponsored program has developed a non-toxic alternative propellant to the commonly used, but highly toxic and flammable, monopropellant hydrazine: New research key to revolutionary ‘green’ spacecraft propellant – US Air Force

The new fuel, labeled AF-M315E,  is an “energetic ionic liquid, or EIL”. It was developed by Dr. Tom Hawkins of the Air Force Research Lab with funding from the Integrated High Payoff Rocket Propulsion Technology (IHPRPT) Program.  AF-M315E  offers nearly twice the energy density of hydrazine, has very low vapor flammability and is non-toxic.

The fuel will be tested in space by NASA in 2015 using an engine developed for the fuel by Aerojet in the project called the  Green Propellant Infusion Mission (GPIM)

The Green Propellant Infusion Mission (GPIM) project will demonstrate the practical capabilities of AF-M315E, a high-performance green alternative to hydrazine. This innovative, low-toxicity propellant is expected to improve overall vehicle performance. It boasts a higher density than hydrazine, meaning more of it can be stored in containers of the same volume; it delivers a higher specific impulse, or thrust delivered per given quantity of fuel; and it has a lower freezing point, requiring less spacecraft power to maintain its temperature.

 

Rockets, Science and Technology, Space Systems

Video: X-51A test flight

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A video of last week’s successful X-51 scramjet test flight: The X-51A soars to new heights – Boeing

Update: More about the flight from Michael Belfiore : X-51A Screams to Hypersonic Success: A nine-year development effort has finally paid off to create air-breathing planes that can hit Mach 5 and above. PM gets an update from program officials about what this means to the future of flight – Popular Mechanics – May.9.13.

Living in Space, Space Systems

Space travel and the spin on the gravity of the situation

It always annoys me when some article or TV report says “space travel causes [some ailment]” when what they really mean is that prolonged weightlessness causes that ailment. We are, after all, traveling in space right now. We just happen to be traveling on a modest sized object that grips us to its surface with a level of gravity to which we have become accustom.

The Moon and Mars also have gravity and we don’t know yet if the levels of gravity on those bodies are sufficient to maintain good health for long stays.

In free space, we can rotate our habitat so as to create apparent gravity via the centrifugal effect.  This is referred to as artificial gravity or spin gravity. So far, no space station has been constructed to do this. This is basically for two reasons: (1) The main goal of the stations was to use microgravity for a range of basic and applied research areas; (2) It was simpler and cheaper to build non-rotating stations.

Here’s an article that discusses this missing piece in our in-space infrastructure: Why Don’t We Have Artificial Gravity? – Popular Mechanics.

Eventually though, practical spacefaring will require the implementation of spin gravity and the sooner we start to develop ways to do it, the better.

Joe Carroll gave an informative online course on the Space Show in which he reviewed a wide range of issues involved in spin gravity: Lesson Three Presentation Material, 5-3-11 – The Space Show Classroom Blog

He is an expert on tethers and the first implementation of spin gravity will most likely involve connecting a habitat to a counter-weight via a long tether. The rotation rate of this “dumbbell” arrangement can be much lower for a given level of spin gravity compared to rotating a modest sized structure. It will be awhile before we can build a large wheel shaped station like that seen in 2001: A Space Odyssey.

You can use the online tool SpinCalc to vary values of spin gravity for different spin rates, radii and tangential velocities.

The Space Studies Institute is proposing the development of the orbital G-Lab to study the effects of long term exposure to fractional levels of earth’s gravity on lab animals:

Update:  A good review of many aspects of spin gravity: Gravity in the Elysium Space Station – Wired Science/Wired.com.