Tag Archives: engineering

Burt Rutan on future of space

At an airshow on Thursday, July 29, in Oskosh, Wisconsin, Burt Rutan, designer of SpaceShipOne, made some interesting remarks about the past and future of private space flight. Key quote:

Rutan said NASA should give 10 to 15 percent of its budget to new space companies like Elon Musk’s SpaceX without regulating how to spend the money. “That would allow them to not (have to) beg for commercial investment, while still working in an entrepreneurial mode.”

Solar sail conference

Solar sail engineers from around the world gathered in Brooklyn last week for the Second International Symposium on Solar Sailing. Ben Diedrich, fellow caver, solar sail expert, and the man behind wiki.solarsails.info, gave two papers. He also emailed me to say that “Japan’s contingent gave several talks – many of which compared analysis of deployment, flight, or steering with actual flight data” of Ikaros. A review of the program [pdf] revealed some fascinating uses for solar sails. I like this paper title the best: “Deflecting Apophis with a flotilla of solar sails.” [ed. Apophis is an asteroid with the potential of hitting the Earth.]

Update: Japanese scientists have now announced that they have been able to adjust Ikaros’s attitude using sunlight.

Another update: Ben Diedrich emailed me the link to read the actual proceedings from the conference. See pg 103 to read the paper on using solar sails to deflect Apophis.

Single Rope Techinque — on the Moon

James Fincannon of NASA took the two images of the Marius Hills lunar pit taken at different times by Lunar Reconnaissance Orbiter (which I posted here) and did an overlay so that the shadow produced by pit’s rim could be easily compared with the rim itself (see below). He then did some calculations based on the sun’s angle of light shining into the cave and came up with the following calculations:

I estimate it is 60 meters from rim to bottom. The floor is flat below the surface. The rocks on the flat surface below ground are in stark relief (hard shadows) compared to above ground due to the sun coming only at one angle while above ground the albedo/reflections makes for soft shadows at this high sun angle (65 deg elevation). I cannot tell if the black portion of the combo image is a slope or more flat floor. Need a different high sun angle or azimuth to fill that in. Still I like the general pattern of the rim matching the shadow on the floor, although the image I found originally has that edge of the cave rim in shadow for a large extent.

overlay of Marius Hill cave

A 60 meter drop is about 200 feet deep. This result is reasonably close to the depth estimated by Japanese scientists, 88 meters or 288 feet, based on images of the same lunar pit taken by their Kaguya probe.

Knowing the approximate depth of the entrance pit raises the much more important question: How will future lunar explorers to get to the bottom of this pit? It is ironic » Read more

Solar powered plane flies for two weeks

Zephr, a British-built solar-powered unmanned plane was ordered to return to Earth after flying continuously for two weeks without refueling. Key quote:

Zephyr is set to be credited with a new world endurance record (336 hours, 24 minutes) for an unmanned, un-refuelled aircraft – provided a representative of the world air sports federation, who was present at Yuma, is satisfied its rules have been followed properly.

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