Showing posts with label cgi. Show all posts
Showing posts with label cgi. Show all posts

Monday, August 18, 2008

Briefing Holloman: Instantaneous Impact Point

As a team, we have been preparing for briefings we have to give at Holloman AFB on Tuesday and Wednesday. We're excited and a little daunted by the task. There will be teams there that have been doing this for a few years. There will be people from Holloman and FAA that are experts in this and want to make sure we're not crazy as a loon with a rocket pack.

One of the single most important aspects of this presentation is that of safety. How are our procedures on the ground going to be? If your rocket goes nuts, what will happen? How will we react? This is actually probably as important as anything else, if not more so, than what you do for the rest of the project. We're not going to run through the whole of what we did to prepare for this, but we would like to talk about the instantaneous impact point.

The instantaneous impact point (IIP) is the spot where the rocket will crash land based on the position and trajectory of the vehicle when things go wrong. This is really crucial to know at any given time during a rocket's flight because that will dictate where the public and uninvolved should be cleared from and what property may be damaged. IIP is actually more important to track than the position of the vehicle since what the rocket may damage is of more concern to the flight safety folks than the rocket itself.

We of Team Phoenicia, with the advise of some friends that work in the flight safety business for a test range, did a quick analysis of The Wind at Dawn. It turned out that the back of envelope calculations we had done for an estimate for our safety zones fit pretty closely to our first order model. With the help of our graphics powerhouse friend up in the cold, cold north, we produced a video for the presentation.



There are a few things to note about this. One, it's not a perfect representation. It's a first order model and therefore needs some fine tuning. Second, you ought to realize that the higher you go, the greater the radius is when the rocket loses its marbles and crashes - if it does at all! Our job is to make sure this is unnecessary. However, the flight folks, Holloman and FAA, really need this. We'll, of course, give them the numbers too if they ask, but we'll wait and see.

IIP: know it or no flying.

More another time. There's a plane to catch!

Sunday, August 10, 2008

A Little More of The Wind at Dawn


This is a frame from the previous Travel Cam video. You can see the relation to the drawing in the post below.

Thursday, August 7, 2008

The Wind at Dawn Flight Simulations

When we set out to enter the Lunar Lander Challenge, we had to do a lot of work to design The Wind at Dawn. There was a whole month spent working out some of the really basic equations and then translating them into some simulations of the flight based on changing mass, throttling, thrust profiles, wind, and several other factors. It was interesting work because it was all tied together. If you consume propellant, the amount of thrust needed to flight at a given height decreases which causes throttling changes which changes the amount of propellant that is to be used. etc. In the end, we had a series of numbers for given time frame snapshots. These were heights, lateral displacements, throttling requirements, thrust, etc. We took these to the ever talented Scott E of Coherent Lighthouse and his nice little IRIX cluster. He did a crazy bang up job and produced the following visualizations of the event.



The first visualization is if you had a 'travel camera' that was back about 3m or so that would allow you to focus on the vehicle as it lifted off and keep altitudal pace with it. Unfortunately, the viz machines choked part way through and we had a deadline, so the video is incomplete. Since the flight isn't really that interesting from this POV, we asked if he'd just give us what he had.



The second visualization is from the point of view of an observer 250m away from the flight path of The Wind at Dawn. This video shows the whole flight.

Let's say that we strongly recommend the work of Scott Elyard. He's a hard worker, able to get work done on short notice, and a good guy all around.