Sunday, January 25, 2009
Here are some additional materials that I recently found for Project Farside.
This comes from the October 1957 Popular Science. The details here are great: note the remarkable little payload probe... this is similar to the Vanguard satellites that were first attempted around the same time. The article says 3.5 lbs! That is tiny for 2009, let alone 1957. For 3.5 lbs, we could add a camera and GPS today. Also keep the date in mind, the month of October 1957 saw Sputnik enter orbit. The frenzy of rocketry to follow is interesting to track.
Also, note the very simple launch tower arrangement. This does match the launch tower in the video posted previously. Only 4 large pins hold the rocket at the aerodynamic cone between stages 1 and 2. These pins guide the rocket for the length of stage 1, running along the wells between each of the 4 stage 1 motors. This is a very short period of guidance, and a very simple method. There dont appear to be any rails, which would add weight. However, the very high thrust of these motors is probably the only way to maintain stability with this system. I would be worried about a hobby attempt using the same technique without massively high thrust motors and large fins. Stage 1, the aerodynamic stable stage, launches with almost 150,000 lbs of thrust, for under 2 seconds. These are R 167,000 motors, and small ones at that: more than one O motor short of a full R. This is exceptional thrust, for less than 2 sec. Probably, any hobby design would call for the use of a longer rail. What is the equivalent of 50 feet per second (a good target speed for stability) at 100,000 feet? For this reason, the O-10,000 would be a perfect first time motor for rockoon work. With a 5 foot rail, and generous fins, an O 10,000 should have no problem going stable. A touch of find cant, or better (but more expensive) yet, a rifled launch rail would spin the rocket up as well. Cameras wont like that, but it would give a better trajectory all the same.
Farside is exciting because it could have probably been used to attempt orbits, and then Moon shots if not abandoned. Given the resources on hand during the core of the space race, it is for the best that we invested in very large, expensive, and complex liquid fueled rockets: they have the power and precision to do all of the things we have been doing in space including flight to other planets and the moon. But one cant help admire the potential of such a small system. And while many companies like SpaceX go the high tech liquid fuel road, bringing the private space industry up to date, there is plenty of room for the amateur crowd to stretch the use of solids and hybrids, and other simple cheap systems.
This rocket achieved (or would have if flown perfectly) about 17,000 mph or 25,000 fps. This is just below the level of orbit. If flown at a 45 degree angle, the reduction in gravity losses alone would have probably allowed orbit (with some staggering of stage times to coast to altitude and then circularize the orbit). In addition, a launch from near the equator in the right direction would gain a further 1,000 fps or so.
This ideal performance is only about 10,000 fps short of a solar orbit... that is to say a Moon shot in this case. Those 10,000 fps are just within reach of a large stage 0. Would it come in the form of 4 Aerobee booster motors? Would this kind of complexity (5 stages, 14 motors) be too much? Would this start to cost more than monolithic liquid propelled rockets? A simple pressure fed stage 0 could be the best addition to such a system. The Thor Able upper stage (Ablestar) was a simple bi-propellant motor of impressive performance, it came online during 1958.