Basics of Spaceflight

April 30, 2013 by 1 Comment

Does this kind of thing get you excited?

Launch Phase Upon completion of this chapter you will be able to describe the role launch sites play in total launch energy, state the characteristics of various launch vehicles, and list factors contributing to determination of launch windows. You will be able to describe how the launch day of the year and hour of the day affect interplanetary launch energy and list the major factors involved in preparations for launch.

Or how about this…?

Interplanetary Trajectories Upon completion of this chapter you will be able to describe the use of Hohmann transfer orbits in general terms and how spacecraft use them for interplanetary travel. You will be able to describe the general concept of exchanging angular momentum between planets and spacecraft to achieve gravity assist trajectories.

If so, you need to read the fabulous Basics of Spaceflight by Dave Doody, a JPL engineer. You can browse it online, but a free PDF version is also available which has much nicer formatting.

It is very clearly written and has a broad scope, covering all aspects of space travel and exploration.

Highly recommended.

basics_of_spaceflight

Filed Under: Space Tagged With: , , , , ,

Vintage NASA Project Mercury documentaries

April 22, 2013 by Leave a Comment

They don’t make documentaries like these any more.

Men in silver spacesuits.  Scientists in white labcoats.  Giant rockets.  Pointing engineers.

IMPORTANT FACTS IN BOLD CAPITALS.

Bizarre soundtracks.

You can see where Gerry Anderson got his inspiration from for Thunderbirds.  Not least the fact that he named the Thunderbirds pilots after five of the Mercury 7 astronauts (bad luck Deke and Wally!).


Project Mercury (1963)

Spaceman

Blunt body


Freedom 7 (1961)

Micro meteorites

Flight path

Filed Under: Space Tagged With: , , , , ,

Spheres vs Blunt Bodies

March 31, 2013 by Leave a Comment

p71

It is always interesting to see how independent teams come up with different solutions to the same problem. Particularly when they make different design decisions, and those alternative decisions can both be strongly justified.

The early years of the space race demonstrate a fine example in the design of the reentry vehicles.

Soviet Vostok designers settled on a perfect sphere with inherent dynamic stability. No attitude control. It needed an all-round heatshield to protect it on reentry. A low centre of gravity and the laws of physics ensured that the sphere was in the correct orientation when the door was blown off and the cosmonaut ejected at 7,000m.

The American Mercury designers went for a blunt body design, which allowed them to place the bulk of the heatshield at one end of the craft, saving weight over the all-round heatshield approach of the Vostok. This required attitude control to ensure that the heatshield was facing the right way when plummeting through the atmosphere.

For both designs, simplicity was a key factor.

NASA has a great article with more detail…
The Partnership: A History of the Apollo-Soyuz Test Project. Reentry Vehicles: Spheres vs. Blunt Bodies

Filed Under: Space Tagged With: , , , , , , , ,