by Robert Brand: I spent the morning before breakfast (5am) calculating speeds for the Median Mars impactors and a new slowing system designed to use the worst case situation – low altitude deployment, but still produce a good sized circle of nodes over 8km wide and have them impact near vertically. Important for the methane airflow in the wind. I have sorted out determination of north and south in the absence of a magnetic field to an accuracy of a few degrees. Worked on the correctional systems for the data and the inclusion of a 1m in diameter soft solar panel – a lot of power! We may be able to have every node communicate with an orbital directly.for relay back to earth. There should be enough battery power for a small battery compartment heater to make the night survivable for the battery.
The impact speed will be between 80 and 90 metres per second and we will begin calculations on the g forces after inertial suppression. It is really fun to get something right and not have issues with the maths.my payloads on my stratospheric balloons usually hit the ground or rocks at 8m/s and we are looking at just 10 times that. We have also survived impacts of 40m/s when the parachutes fail to open and we have never had broken equipment. That includes cameras, trackers and other sensitive electronics. This is looking very easily survivable and very powerful. I like it when a plan comes together as well as this one has.his is more than just “doable” This is magnificent.
Thought for the day (after this mornings work) – if you want to work on spacecraft – study mathematics, Astronomy – study mathematics. Rocket propulsion – study mathematics. Navigation – study Mathematics. The core for success in space is Mathematics. It is consistent across the whole sector. Ha! More work before breakfast!
The diagram is from Todd Hampson – one of our core team at ThunderStruck Aerospace. Todd is calculating the braking speeds with air density info, gravity friction, etc, etc. from a supersonic deployment speed in the martian atmosphere, taking into account a lot of transonic forces. Smart guy. The diagram is close to the finished penetrator design, but there are several changes. The design being tested will weigh about 6Kg and use an initial parachute of 2m that gets discarded at altitude.
Nick Howes, the Team Leader, commented: Parachutes may not be viable, as the air mass will be so low surely?
Robert: Nick, what you don’t know is why you have me working with you on this project and the entire ThunderStruck team. When you are traveling at half the speed of sound a 1% density makes a real difference. Even individual air molecules will eventual pull a satellite from orbit. You can get verification from you UCLAN counterparts. It is all in the maths and the previous work that Todd and I put into understanding the dynamics of transonic air-flows has given us the ability to know what happens in the earth’s stratosphere and that is very similar to Mars. You must trust the experts here. I am currently working on testing a 4 rotor flier at 34Km. There is low density air there, but it is how you use it. This is what opening a 2m chute will do on Mars at high speed with a 6Kg penetrator. It does not do much once the speed reaches 30m per second, but it does slow the beast down. This graph is adjusted for Mars gravity, and air densities. The rate of slowing is immense when the speed is greatest (top of chart). Todd wrote this transonic spreadsheet. It is incredibly complex.
Nick: superb, thank you for the clarification
Robert: I will make public what I can without compromising the mission or the bosses requirements. I hope that you find our design discussions right here on these pages useful. As you can see today, Nick, the boss, is not an expert on parachutes in the martian atmosphere. His brilliance lies elsewhere such as thinking up this mission in the first place. he has to defer that stuff to me and hopefully I will bring the engineering side to the table along with all the dynamic stuff and the electronics and radio gear. Likewise I know nothing about the stuff that Nick does. Individually this mission would have sat on the bench, but these days, with a dynamic team with their own areas of expertise, it is full speed ahead.
Nick: Once the iteration completes (and that has to be soon) then the test/modelling will happen… then we’ll know size for all the science package. At that point., you’re go to start work on comms too… to fit it inside, with the methane sensors etc. We’re prototyping on Arduino/Pi type devices, but will fab radiation hardened custom setups for final flight testing etc
….and this all happened before breakfast…