High Power Rocket landing Application Help
My name is Dave, I build and fly large rockets which sometimes go several miles high. We recover the rockets by parachute. I am trying to develop a spreadsheet that utilizes Windy's multi-level wind data to predict the landing point of a rocket launch. The rocket is assumed to go straight up to its estimated altitude(AGL), deploy a parachute and drift down. The idea is to help decide if the launch should proceed based on where the rocket may land due to the forecasted winds - possibly in water or trees or other areas that are hazardous for whatever reason.
This is very similar to the high altitude balloon landing point problem.
We generally deal with elevation readings above ground level.
I fly in a sod farm North Branch, MN, where the elevation is about 830 ft. See the pic below.
If I fly a rocket to 5000 ft AGL, this is about 5830 ft AMSL.
I will utilize the wind data between 6400ft and 5000ft to start my prediction and work back down.
I read in another post, that the vertical elevations are AMSL, however, more specifically isobars.
I'm struggling to understand this concept, specifically, when the isobars take place.
If the launch site is located at 830ft above sea level. What do the winds at the surface, 330 ft, and 2000 ft+ mean?
Windy Community Isobar discussion
Your area is relatively flat so real altitude and model altitude is about the same.
Model's surface wind (for ECMWF model) is computed for 874 ft AMSL.
Wind at 330ft AGL is at 1200ft AMSL (aprox.)
Wind at 2000ft is the wind on an (isobaric) surface with pressure 950 hPa. This surface lies usually at 2000ft AMSL (higher in high temperature conditions e.g. summer, lower at lower temps).
All wind levels expresed in hPa are AMSL.
Isobaric surfaces in hPa correspond to altitudes AMSL
as described by International Standard Atmosphere
50 milles southwest from your location, NOAA/NWS has a radiosonde station named MPX
that makes upper-air observations.
So you can find real observations of upper air winds (not forecasts)
As I know, people in radiosonde stations use a special software for recovering radiosondes. You can ask them to help you.
Finally, here you can find people with deep knowledge in predictions of landing zones!
I tested this application
with (imaginary) data
Burst altitude:1500 m (5000ft),
ascent rate:300 m/s (1000 ft/s) and
descent rate: 5 m/s (15 ft/s)
Hope it hepls.
Thanks so much for your help and explanation! Your first post really helped my understanding of what's going on within Windy and the forecasts.
I would love to be able to use the Stratos or another high altitude balloon simulator.
Unfortunately, I oversimplified the flight of a high power rocket.
For most high powered flights, we use two parachutes. One is deployed at apogee, and the other is deployed at a pre-determined lower altitude. The apogee chute, or drogue chute is small and facilitates a quick descent. The main parachute, or secondary chute facilitates a soft, safe landing. All the high altitude balloon software only allows for one parachute, which doesn't work for my scenario.
Thanks again for this explanation!
With this information, I think I've pretty much got my simulator working - need to give it a real world comparison.
However, for the plains of the midwest, it will work, but if we go out west, to say Colorado, The Norther Colorado Tripoli site has gps coordinates:
This site is about 5500 ft in elevation starting out.
So, please correct me if I'm wrong -
The surface wind is the model altitude , computed at 5522 ft
The value at 330 ft, is actually computed at about 5800 ft
The next couple of values corresponding to 2000, 25000,3000,5000 are not valid, because those isobars intersect with the land, correct?
Maybe a silly question, but Is it possible to get wind data above 45000 ft?
I've been unable to find it.
Have you had a chance to look at my last two questions?
Really appreciate your help!
Good morning Dave.
Firstly I want to say I'm sorry for that late response
(and for my bad english!).
For your first question, you are right.
Please read my answers to a similar question from Aspen, Colorado.
For your second question (If is it possible to get wind data above 45000 ft?)
Windy provides upperair data up to FL450.
Usually no one flies higher!
But, I have to say weather ballons go up to 100.000ft (or even higher), the wind field above tropopause is relatively smooth and doesn't change a lot day by day so you can use data for these levels (>45000ft) directrly from radiosondes.
I suggest you http://weather.uwyo.edu/upperair/sounding.html
For example: Radiosonde from 23 Apr for Denver, CO shows
I think you can use stratos simulator even for high power rockets with drogue chute and main parachute.
You have to use it two times for two different computations.
Let's say you lift-off from 800ft AMSL (location A),
go up to 60,000ft,
deploy the drogue chute and descent at 30m/s
to predefined alt. 10,000ft.
Then use the main parachute (descent speed 5 m/s) from loc. C
to landing zone.
Lift off of imaginary location A1 at 10,000ft, and "land" at loc. C.
Use max. possible ascent rate and drogue's (relatively fast) descent rate.
By using loc. C1 as lift off location (elevation 800 ft), predefined 10000ft as burst altitude
and parachutes (relatively slow) descent rate
you can have a computation of landing location.