Ngwenya & Ochre
Global Nominee
Ngwenya & Ochre received a Global Nomination.
Develop an approach for characterizing the composition of asteroid for mining potential and a process for mining different compositions. Explore a possible division of labor involving different types of vehicles (e.g. sensor units, drilling units, power gathering and distribution, extracted resources handling and transferring). Consider solutions for moving said asteroids between different orbits and/or consequently make periodical adjustments to keep them in place. Analyze how your idea would cope in some of the given scenarios or outline a scheme of your own.
Advice: Use this Document (https://onedrive.live.com/redir?resid=C0ACCE17125469F2!3483&authkey=!AFXeDk93ZgICxB8&ithint=file%2cdocx), because it is better formatted.
Brief:
An unmanned probe using off-the-shelf technology and proven techniques to return a sample of asteroid regolith/material to Earth’s orbit. Architecture is based on the Rosetta/Philae mission, however due to the smaller dV requirement, it additionally allows a return flight.
Introduction:
The people behind the Rosetta, Hayabusa and so many other Missions were Pioneers, doing what nobody else did before: Exploring a completely new world: Now we are going the next step: "Asteroid Mining" - Scientific research connected with economical possibilities. By learning out of the problems of former missions we are able to create an even better model. Philae" showed us in November 2014 what we are able to do and what we need to improve. That's the spot where we are starting:
Figure 1: Wireframe-Design of Lander "Ochre"; Credits: Own Design
The Lander
The last time humanity landed on an asteroid we brought back 1 g of Material. Doing something again and being able to do proper research means that everything gets bigger and better. Our first goal was to bring back as much Material as possible. Originally, we aimed for 50kg, 100kg or even higher. With the limited time available to design the mission, time our plan and concept surely changed. We decided to create a lander, which is able to powered land on an asteroid, collect the material, and bring it back together to the mothership, which then returns to Earth to analyse it. We designed on paper, on the Computer (Here is our 3D-model of our model: https://skfb.ly/NBNM) and calculated lots of different values. And there it is: Our model. Able to carry up to 10kg material back to Earth to find out more about the Composition of Asteroids, the Origin of Life and many other things, which can be measured by all of the other Instruments.
We decided to name our Oribter "Ngwenya" and our Lander "Ochre". (Under this link a model of the Oribter-Lander Complex can be found: Guys I decided to upload the Lander-Orbiter Complex (gives a better overview): https://skfb.ly/NHVQ)"Ngwenya" is the worlds oldest known mine, located in Africa. "Ochre" is the material mined from that site.
Figure 2: First Experimental Design of Lander "Ochre"; Credits: Own Design
The Mission and Mining Details
But let's go into some more detail: How is this whole Mission working?
When orbiter “Ngwenya” enters Deimosian orbit, it will begin to scan the surface & transmit the results back to Earth. A landing site will be selected, and the probe will be launched as it can be seen in Figure 3.
Unfortuantely this Figure can't be displayed in the PoText editor. Use the One Drive Document instead please!
Figure 3: Possible Landing Spot on Deimos; Credits: Edited Version of "Deep space mission planners are eying Deimos, a moon of Mars, as an exploration target for humans. Here, the path to reach the Martian moon is laid out. 2014, Photograph, Space.com, accessed 24 April 2016,
It is expected that deorbit & landing on Deimos will require approx.. 120 dV, with the excess allowing for return flight & potential cross-range capability. The rest of the calculations for the lander can be seen under (1) in the Appendix.
When safely landed on the surface, drills located in the feet will engage into the asteroids surface. Safely anchored, the reaction wheels can dump their momentum.
Once the craft is fully prepared, the primary drill will activate. The whole concept can be seen in Figure 4. The molten salt battery is designed to provide sufficient power for the drill to operate for 60 minutes, by which time it will have extended to its full operational depth of 680mm, and extracted 3375cm3 of material, filling the internal 15x15x15cm ships cargo bay.
Figure 4: Drill Head (Tricone Bit) on "Ochre" to do the Mining Process by using an Archimedes' screw ; Credits: Edited Version of "Tricon Bit,
Using a ‘typical’ rock density of 3.40 g/cm3 this should weigh 11475g.
Due to Deimos’s known low density, it is highly likely that ice and similar low density materials will be mined additionally, with an anticipated mixture of 80% rock to 20% ice, giving the expected cargo weight of ~10kg.
Note that the ‘excess’ dV above also allows for uncertainty regarding cargo weight return.
When the cargo container is filled, the extended drill is retracted, the landing drills are retracted and the now molten salt battery is exhausted through prepared ports to assist with rebalancing the probes CoG.
The lander is then launched from the surface of Deimos & returns to the orbiter, redocking using its ‘probe’. The orbiter then boosts out of Martian orbit & returns to Earth.
Figure 5: Porkchop plot for Earh-Mars launch windows 2016-2025; Credits: CuriousMetaphor (Reddit)
LAUNCH PROFILE
From LEO, the next best launch window is 16 May 2018, which offers a 7800ms launch window (See porkchop - Figure 5) with a 6 Jan 2019 arrival time. Due to the low thrust typical of an ion engine, multiple boost passes are used to raise apoapsis prior to the window, with the final boost occurring at the preselected time. Upon arrival to Mars space, "Ngwenya" performs an aerocapture using the Martian atmosphere. Details pending. The Calculations on the mass and other important values can be found in the Appendix under number (2). Expectation of multiple passes being required due to lack of aeroshell.
"Ngwenya" then burns to capture into Deimos’s orbit, and begins a polar mapping orbit before selecting a landing site with the guidance of Mission Control.
The next return window is not until June 2020, so there is plenty of time to choose a perfect site.
When the appropriate site has been chosen, "Ochre" undocks from "Ngwenya" and thrusts its way to the surface, and begins previously described mining operations.
The lander then returns to "Ngwenya". Using its RCS system, the mothership redocks with the lander, and at the appropriate time begins to burn to exit Mars’s sphere of influence (SOI).
Due to the complexities of burning to exit first Diemos’s SOI then mars’s, We are unable to provide an applicable porkchop plot, however a standard ‘dV map’ tool suggests a return dV requirement of 2.7km/s, assuming aerocapture in Earth’s orbit.
Again, multiple passes would be used in order to allow stable capture.
Once safely in orbit, a domestic mission would need to be launched to retrieve the sample as the lander was not designed to survive a landing on earth.
Issues:
The tool used to generate the porkchop plot above was unclear as to whether the figure additionally included a capture burn into Mars’s SOI. If it does, then the dV requirement is significantly reduced.
The dV requirement includes a small amount of ‘discretionary’ fuel. It is possible that the craft could additionally perform an analysis orbit around Phobos, however this document does not take this situation into account, especially as the lander (the primary focus) has been designed to mine/prospect Deimos’s surface only, and has no capability to return samples from Phobos.
Aerobraking using Earths atmosphere includes a nonzero risk of the spacecraft being destroyed or of the sample being contaminated by domestic gases. While the sample container is carefully designed to be sealed when the drill is retracted, there will be no way to state with absolute certainty there was no domestic contamination.
Figure 6: Second Wireframe-Design of Lander "Ochre"; Credits: Own Design
Outcome
Whatever the outcome of the mission something will be learnt. Even if the landing goes completely wrong we know next time what we can do better and which things we need to improve. This is what being a human is about: Learning stuff and Developing yourself and your knowledge.
If the Mission is successful we could know more about the Composition of the Asteroids. We could have more information about their shapes, their history and influence on our world. There are so many things out there we don't know about yet and what it is worth looking for.
We could find some Metals like Nickel or Iron in the ground, Carbon or something else. Most interestingly it could prove or disprove panspermia: Information about the origin of life and the boundless curiosity of all human beings, which has led us to accept this challenge and provide our solution.
Appendix:
(1)
LANDER "Ochre":
1.7m high (including docking probe & landing legs) x 4.7m x 4.7m (landing legs)
Shell/framework: 38000g (wire frame, steel/titanium mix)
Solar panels 1500g (2, located opposite sides of body)
Antenna 50g (Simple wire loop, released on initial undock)
Computer: 500g (chosen to be small & rad-hard)
Flywheel: 19500g (motor & 3-axis flywheel of 5000g each)
Tankage: 3000g (insulated cryogenic storage)
Piping/plumbing: 850g (Insulated & compact pump)
Engine: 50000g (320s Isp, LOX/RP1, 50N)
Drill 25000g (80mm drill, 680mm ‘travel���)
Molten Salt Battery 10000g (1000W/h for 1 hour)
Laser rangefinders 300g (for landing & docking)
Camera 500g (10.8MP with 256GB internal storage)
“Dry” flight mass: 148,900g (Assumed to be 150 kg)
Oxidiser: 28235g (Liquid oxygen)
Fuel 11764g (Rp-1 “kerosene”)
“Wet” flight mass: 188,899g
dV=Vex * LN(Wet/Dry)
dV of lander: ~720 m/s
(2)ORBITER “Ngwenya”
Shell/Framework: 320000g (open frame steel/titanium)
Solar cells: 203600g (7kW , at 30% eff, 1.5AU , 39.52 m2)
Solar Cell retractor: 1200g (close to prevent damage during aerocapture)
High-band antenna 15000g (Earth communication)
Low-band antenna 200g (Lander communication)
Multispectral: 13200g (NAC from OSIRIS sensor package)
Thermal: 9500g (WAC from OSIRIS sensor package)
Ion engine 33600g (NEXT Ion, 4190 Isp, 0.236N,7kW)
RCS thrusters 1200g (4 thrusters to allow redocking, Isp 227.5)
RCS fuel tanks 930g (0.33m2, @1mm Al sheet)
Xenon fuel tanks 188824g (54.84m2, @1mm Al sheet)
Lander "Ochre" 188899g (Lander mass at launch)
"Dry" mass: 976153g (976.15 kg)
RCS fuel: 18000g (docking, 30ms,hydrazine)
Xenon fuel: 300000g (67.43m2, dV 10.6 km/ s)
Wet mass: 1294123g (1294.15 kg)
dV=Vex * LN(Wet/Dry)
dV of orbiter: 10.6 km/s
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