America's Hunting Eyes in the Sky (A Version of the Future)

Thursday, April 7, 2044

Watch out world, because the sky above you just got a lot more watchful.  On April 5th, a US Air Force spokesperson officially confirmed that the MIL-Cast satellite network is more than a communications and observation platform, but is also a space-based weapons platform, as suggested in our 2039 Article "Secrets of MIL-Cast"

"Good morning everyone, I am here to announce that as of 0200 this morning the robotic geoengineering platform Jotunn has ceased operation after illegally entering the waters of South Georgia Island.  At the request of the UN Climate council and with permission from the British government US forces deployed 3 Falcon Earth Observation Drones to perform a kinetic observation of the Jotunn...."

When asked why the Air Force was finally acknowledging the offensive capabilities of the MIL-Cast General O'Neill was rather blunt.  "We're running out of the darn things, every other week we need to 'kinetically observe' some bad guys and hiding the launches was too much of a hassle"......

From our research, we believe there are between 20 and 30 thousand Falcon satellites in the MIL-Cast network.  With a mass of about 50 kgs, they share many characteristics with other atmosphere skimming communication/observation satellites used by civilian firms.  Most experts who were willing to go on the record believe the biggest differentiator for the spacecraft comes in the way they are designed to re-enter the atmosphere.  Civilian satellites are designed to safely break apart when they enter the atmosphere. The Falcon appears to be able to precisely control entry depending on the mission when the craft reaches its end of life it will disintegrate like a shooting star, as many Americans saw in the 2040 Seatle Summer Olympics opening ceremony.  The secondary re-entry method allows 10-20 kg of the vehicle to strike a target with over 100 megajoules of kinetic energy.  

Would you like to know more?

This article is a continuation of my post "Looking at the Future of Low Earth Orbit".  Basically, the idea is that a future government might use really low orbiting satellites as more than just communications/observation platforms.  As satellites get cheaper and cheaper to launch it isn't crazy to imagine that a large nation-state like the US would look for additional ways to weaponize space.  The idea of dropping heavy objects from space as a weapon has been around since the 1950s.  The proposed Falcon above would be a much smaller vehicle than what the Air Force has investigated previously.  

The 100 Megajoules was based on the Wikipedia entry on how much kinetic energy orbiting objects have.  To put things in perspective 100 MJ of energy is the equivalent of about 23kg (52.5 ish lbs) of TNT.  Depending on where the Falcon hits the explosive energy would be enough to either really mess up your day or to just really really surprise you.

For those of us concerned about peace one thing to find comfort in this suggested weapon is that at this time I have no good idea on how you would actually make a satellite that goes magically from safely breaking up to something that will stay together at speeds high enough to do real damage.

I hope this was interesting, questions, comments, and general feedback are welcome

Fricken Rockets Getting Boosted by Fricken Lasers (oh its a bit longer now)

In part 1 of Fricken Rockets Getting Boosted by Fricken Lasers we got some background on the concept of laser enhanced rockets.  (If you haven't read it yet, I would suggest clicking here first) 

Powering our Saturn 5's electric turbopumps is incredibly energy-intensive, requiring almost as much energy as the propellers on a nuclear carrier.*  The variable that most directly impacts our turbopump's energy demand is the flow rate of the engines, the flow rate for the engines is dependent on the mass of the spacecraft.  The bigger our spaceship, the more flow rate we need to keep the engines fed.  The Saturn 5 was capable of transporting 140,000 kg to Low Earth Orbit for sake of comparison a SpaceX Falcon 9 Full Thrust is capable of transporting 22,800 kg to the same orbit**.  The Falcon 9 Full Thrust uses its 9 Merlin Engines to achieve about 16.3% of the payload capacity of the Saturn 5.  Each Merlin Engine has a massive turbopump supplying 7.5 MW of pumping capacity, meaning that the Falcon 9 FT needs about 67.5 MW of total pumping capacity.  Observant readers, with probably insane levels of recall, might note that the Saturn 5's first stage pump requirements totaled 205 MW when we compare this to the Falcon 9 FT's 67.5 MW turbopump power we see that the Falcon has about 32.9% the total pump capacity of the Saturn 5.  What the Falcon 9 has over the Saturn 5 in our energy concerns is that there is relatively more surface area for our lasers.

For our Saturn 5 calculations, we assumed that about half of the area of the first stage would be devoted to our power receivers, giving the lasers about 200 square meters of effective area to target.  A Falcon 9 first stage is 42.6 meters tall and 3.6 meters in diameter, that means that if we covered the body of the first stage with collectors our lasers could reasonably expect an effective target area of about 75 square meters.  This surface area is fantastic news laser boosted rockets while 75 meters is only about 38% of the area of the Saturn 5, the energy demand for the Falcon's pumps is only 32.9% of what the Saturn 5 needed.  Using our 40% conversion efficiency, we can estimate that the rocket will need to receive 168.75 MW  of energy from the lasers (67.5MW/0.4).  The average peak flux of energy on the rocket would be 2.25 MW/m^2, or about 12% less than what the Saturn 5's receivers would need to handle. 

Scaling down to the Electron rocket the math gets even more interesting.  At 17 meters in total height and 1.2 meters in diameter, we can conservatively estimate the ability to have 6 square meters of receivers.  These 6 square meters will need to supply up to 1 MW of power to the pumps, giving us 2.5 MW of laser energy needing to get to the rocket (1MW/0/4).  For the Electron rocket the panels would only need to handle 416 kW/m^2 of flux (2.5MW/6m^2).  While this isn't a small amount of energy, it is way more manageable than what would be needed for larger rocket launches.

By modeling three different sizes of rockets we can see that the smaller the rocket the smaller the energy overall needed to power the turbopumps.  A combination of needing less energy for the turbopumps in tandem with increases with relative surface area gives an exciting opening for developing laser enhanced rockets, start small and build bigger as technology improves.*(3)

Developing laser Enhanced Rockets might follow a timeline something like this

Step 1
Wireless power transfer testing.  Create a competition where teams are challenged on their ability to have a combination system capable of transferring Energy densities of over 400 kW/m^2 without exceeding design envelope for first stage rocket body simulant

Step 2
Wireless power transfer testing with moving targets
Winners of Step 1 and additional applicants will compete to wireless beam energy at sample liquid fuel rockets.  These rockets will still use traditional turbo-pumps, teams are judged on their ability to continuously supply a set energy intensity to the rocket.

Step 3
Small Scale Pump testing
Competing institutions will be challenged to build liquid fuel powered sounding rockets with electric turbopumps.  Scoring parameters might include factoring what percentage of power for the turbopump came from wireless energy sources.

Step 4
Moving into commercial development of electric turbopumps

Step 5 Launch a spacecraft where some of the power needed for launch comes from wireless energy


Step N
Next-generation laser enhanced competition, as energy densities of long range wireless power transfer increase to certain pre-determined values, organizations like NASA and DARPA have competitions where teams compete on their ability to propel rockets where some amount of direct thrust comes from heat provided by lasers.

 (at this point I ramble a bit, feel free to keep reading, but I won't judge if your eyes just glaze over and you just decide to read something else)

Developing a laser enhanced rocket system will not be an easy undertaking, while the abstract principle is straightforward there are many risks to commercialization.

Cost of developing the laser platform will be the biggest challenge, our world is rife with innovations that came too late after market forces chose a solution.*(4)  Theoretically, a laser enhanced rocket should be cheaper than a more conventional design in the real world this is not a guarantee.  Getting laser enhanced rockets to the point where they can compete on cost will not be easy.

A best-case development scenario for laser enhanced rockets would come from a partnership of multiple space launch companies agreeing to implement the technologies mentioned above.  Each partner organization would share the cost of the laser power base stations maintenance and upkeep. 

Realistically for laser enhanced rockets to become a mainstream innovation the number of launches will need to increase drastically.  Frustratingly for futurists, we need a large volume of launches from the same general geographic vicinity and for those launches to have a fairly similar first stage flight path.  The more variation in launches the less useful our laser platforms would be (or more expensive as the lasers would need to cover more area).  These realizations should not be treated as an absolute negative.  For much of the commercial sector flexibility in space-craft orbits is incredibly useful, but for projects like sending missions beyond the Earth-Moon system, a standardized orbit isn't necessarily a bad thing.  A standardized orbit and rendezvous location would allow for the development of an orbital dry dock facility.  At this drydock fuel and materials could be stockpiled for future missions.  Refueling and assembling in orbit could allow for much more flexible deep space missions, instead of requiring the first missions to Mars to produce all of their return fuel on Mars mission planners could take advantage of fuel stockpiles that built up as secondary payloads for other launches.

Another approach to improve the utility of laser enhanced rockets in the early stages is by creating an open standard booster stage and docking mechanism.  These open standard boosters could supply additional early-stage power with a more narrowly defined flight path than a full first stage. 

I hope you found this idea interesting, I know its a complicated topic, feedback and questions are welcomed.

*according to the Wikipedia article linked above, a Nimitz carrier's nuclear powerplant supplies about 260 MW of power to the propellers, vs our 205 MW of pumping power (some might say 78.8% isn't almost but I'm gonna, because finding analogous power requirements was wasting way too much time)

**okay so not like perfectly exact, this is because the Saturn 5 article lists its lift capacity for getting to an orbit of 170 km with an inclination of 30 degrees, on the flip side the Falcon 9 Full Thrust just lists low earth orbit and an inclination of 28.5 degrees (where low earth orbit isn't well-bounded) for those who want to crunch the numbers in greater detail to minimize the confusion on the comparison please feel free to let me know.  That being said these numbers probably get us in the ballpark.

*(3)  we shouldn't ignore the fact that turbopumps do in fact get more power-efficient as they get bigger.  The Electron can only get about 200 kg into orbit less than 1% of what a Falcon 9 FT can get into orbit, at the same time, the Electron's pumps need about 1.48% of the power than the Falcon 9 does.  Basically, Falcon 9's can move 48% more cargo per unit of pumping power (not a useful actual rubric but interesting)

*(4)  this is along the lines of BetaMax vs VHS or BluRay vs HDDVD, not some kind of conspiracy

*(5)  we are going to assume these panels are designed to be readily added to a rocket and have the appropriate mass properties

The best-case scenario for a country like the United States would be something like this. 

The US Airforce in a continuing desire to increase launch cadence declares that launches must meet certain cost performance goals, to that end they offer affordable access to an Air Force owned power transfer station and a partnering business would supply the necessary panels*(5) to capture the energy required for launching.  The added weight of these panels and the associated electrical sub-systems is offset by the improved fuel efficiency as more rocket fuel can be used to actually propel the spacecraft.

Without a government backing laser enhanced rockets, we are unlikely to see this technology hitting mainstream uses.  The aerospace industry has sunk billions of dollars developing the rocket technology they use

Fricken Rockets Getting Boosted by Fricken Lasers

(now for part 2 of "The Polls Are In")

At its most basic, rocket science sounds really easy, just get something going fast enough that it will leave a planet's atmosphere.  Once you start accounting for things like cost efficiency it starts getting harder.  Over the past 20 years, the barriers to launching into orbit have dropped dramatically, with companies like Blue Origin, Rocket Labs, and SpaceX competing against traditional launch firms, prices have started to come down.  Space tourism is still out of reach for much of the world's population, but for businesses that need satellites affordably transported into orbit, times have never been better.  A key driver in lowering the barrier of entry to launching a rocket comes from a combination of being able to launch smaller/lighter satellites with more affordable rockets themselves.  

There are several ways to make a rocket more affordable, better manufacturing techniques, reusing components, large volumes of production, and making a rocket's engines more efficient.  For each of these cost-saving techniques, there are countless proposed approaches to make improvements.  Making rocket engines more efficient is an incredibly complicated challenge, where engineers must account for the chemical reaction creating thrust, the heat produced by the engine, moving fuel fast enough to keep everything moving, and countless other subtle variables.  One possible way to enhance engine efficiency is to make the rocket's exhaust hotter, hotter exhaust equals more thrust for a given amount of fuel*.  Scientists Arthur Kantrowitz and Wolfgang Moekel realized that the boost of higher exhaust temperatures didn't necessarily have to come from the reaction of rocket fuel and its oxidizer.  In the 1970's they proposed using lasers to enhance the exhaust temperature of a rocket.  Instead of having to carry rocket fuel and liquid oxygen, these laser enhanced rockets would only need to carry a propellent, like water.  

Laser thermal rockets would benefit from having a relatively safe first stage if engineers noticed any problems with the rocket, they could simply turn off the lasers supplying the heat power and drastically reduce the risks faced by those near the launch site.  This boost to safety comes with a cost, having enough powerful lasers to heat water to high enough temperatures to propel a decent sized rocket would be incredibly capital expensive, consequently, laser thermal rockets have been relegated to small scale academic research.  What laser enhanced rockets need is a path from academia to industrial use.  Enter the electric turbopump.

Turbopumps are what you think they are super powerful pumps inside of rockets that help to make sure that there is always the right amount and mix of fuel and oxidizer.  For the Saturn 5, these turbopumps were truly massive, producing 41 MW of power (55,000 brake horsepower) to move 58,560 liters (15,471 gallons) of rocket fuel and 93,920 liters (24,811 gallons) of liquid oxygen.  To generate all this power it was necessary for engineers to make a complicated design that diverted some of the energy of the rocket motor to powering the turbopump.  The aerospace company Rocket Labs has recently broken with industry traditions and developed the Rutherford Engine a rocket engine that uses a battery-powered turbopump.  This innovation of a battery-powered turbopump is possible due in part to improvements in battery energy density.  While development is very exciting for the small satellite launch community, the energy requirements of fluid pumping for larger rockets make this innovation unlikely to scale if batteries are used as the energy source for the turbopump.  

Larger rockets would need a lot of power to run their turbopumps.  For the Saturn 5's first stage you have 5 engines needing 41 MW of pumping power each.  Each of these engines will need to run for 168 seconds, and assuming a safety margin of 12 extra seconds of burn time, let's say the pumps need to be able to run for 180 seconds (3 minutes).  We also need to assume that powering the turbopumps is only 90% efficient, meaning the electrical systems for each turbopump would need to supply 45.6 MW of power.  Putting all our variables together we see that our 5 engines, consuming 45.6 MW each, for 180 seconds would require 41.04 GJ** of energy.  That's a lot of energy, to put things in comparison a Tesla Model 3 with the largest battery option has a 75 kWhr battery which holds about 270 MJ (0.27 GJ).  Our new Saturn 5 would need 152 Tesla Model 3 battery packs to run its turbopumps for all of 3 minutes.  It gets more complicated, traditional batteries have a maximum discharge rate; it would be unlikely that we could design a battery pack that would be able to go from 100% charge to nothing in only 3 minutes***.

Instead of batteries what if our turbopumps got most of the electricity from power wirelessly sent from base stations?  

Keeping our requirements from the previous section of 5 engines each needing 41 MW of pumping output running for a period of up to 180 seconds, but now we have a different consideration make sure we can safely transmit sufficient power to run the pumps while keeping the system's weight to less than that of using batteries****.  The two most popular long-distance/low loss means of transmitting energy wirelessly are lasers and microwaves.  Converting laser light into electricity is currently estimated to have an efficiency from 40-50+% that means that if your system needs 1 watt of power, your laser will need to have an output of about 2 watts.  Documentation on using microwaves to transmit DC power has been harder to come by, but values as high as 95% are listed on Wikipedia.  Conversion efficiency is important from a heat management standpoint, the less efficient the conversion process, the more heat the vehicle's design will need to account for.  

Beyond conversion efficiency, engineers would need to account for the maximum flux the receivers can handle.  Flux is a measure in Watts per Square meter of how much energy an object can handle, for example, certain plants are adapted to grow in shade, they are happiest when they get soft indirect light if the plant gets too sunlight, they could end up damaged.  For something like a Saturn 5 to get its 205 MW of power to the turbopumps, our 40% efficient panels would need to be absorbing over 512.5 MW of laser energy*(5).  The Saturn 5's first stage was 41 meters tall and 10 meters in diameter, we are going to assume at any given moment about 200 square meters of the first stage will be able to absorb our laser's energy.  To achieve our model's requirements our panels would need to be able to handle 2.5625 MW/m^2, for sake of comparison sunlight in space produces about 1360 watts/m^2.  The power receivers would need to handle 2000x more energy than sunlight.  

We should keep in mind that the estimated power hitting the receiver assumes that the lasers are targeting a flat surface.  A more detailed analysis would factor in the curvature of the rocket, where only a small percentage would experience the 2.56+MW/m^2 of peak laser radiant flux.

At this point this post is already way longer than I originally planned, it turns out rocket science is hard and I hadn't done any actual deep analysis until I started writing and I would like to give this concept the analysis I feel it deserves.  What to expect in the next post.

A rant about the square cubed law, the Saturn 5 has less area per unit mass than say a Falcon 9 or an Electron rocket, this means the lasers need to power the Saturn 5 pumps would need to have a much higher energy density when hitting the side of the rocket.  The 9 Merlin Engines on a Falcon 9 have 7.5 MW turbopumps.  The Electron Rocket from Rocket Labs has 9 Rutherford Engines, with each engine requiring roughly 75 kW to power their turbopumps (37 kW for oxygen, 37 kW for fuel)

A proposed timeline for how commercialization might go (start small and build)

Thoughts on cost efficacy of this proposal (it would depend on many market forces and how long investors are willing to amortize costs)

I hope this was an interesting start

*there are probably some exceptions to high exhaust temperature vs produced thrust, but from this rocketry 101 article from NASA it appears this is generally the case https://www.grc.nasa.gov/WWW/K-12/rocket/rktthsum.html

**GJ is shorthand for gigajoule or 1 billion joules, lots of energy MJ is a megajoule 1 million joules

***This is to acknowledge that supercapacitors are a thing, while they have a lower energy density, they can discharge that energy much faster than a traditional battery can.  So yes, they are a thing, and yes, they might be part of the solution, but giving supercapacitors their proper depth would make this article way way too long

**** I mean technically the most important comparison is competitiveness with traditional turbopump launches, but c'mon, do you guys want a book?  (seriously if you do let me know)

*(5) this is just the laser hitting the spacecraft, depending on energy lost to the atmosphere we could be seeing some really big lasers being needed to get power to the spaceship

*(6)

Looking at the future of Low Earth Orbit

One hundred kilometers above the Earth's surface space is starting to fill up with debris, with hundreds of now defunct satellites and tens of thousands of smaller bits of waste.  As the cost for launching into space continues to go down the volume of satellites will continue to rise.  While we are unlikely to see a dramatic loss of orbiting equipment as portrayed in the movie Gravity, there is a risk that the volume of debris could reduce the overall life expectancy of spacecraft in more crowded orbits.  Researchers from around the world have suggested various ways to clear orbits, ranging from designing satellites that will intentionally fall back to Earth at the end of their useful life, to using high tech harpoons, and using lasers to slow down materials sufficiently for them to burn up in the atmosphere.

As of May 2019, there have only been handful of small-scale experiments intended to test some of the proposed methods of eliminating space debris.  While the results for these removal methodologies appear to show positive results, humans have yet to establish a standard for cleaning our space-based messes.  While all reasonable solutions to space debris should be given consideration, this article will make an argument for the use of satellite-based laser platforms as a way to control space debris.

Lasers can be used in two primary ways to eliminate space debris ablation and vaporization.  For most readers when they think of using a laser to clear space debris, they are likely thinking about vaporization.  Vaporization is achieved by aiming a strong laser at a piece of material as long as it takes to heat the material enough for it to be broken down into microscopic components.  This requires a very strong laser, several megawatts, and as a result a large amount of power.  The approach preferred by researchers at NASA deals with ablation.  Laser ablation happens when a strong laser is focused on a target for several hundred nano-seconds, this very short pulse is sufficient to cause microscopic pieces of material to be ejected from the target material, while leaving the remainder of the target seemingly unscathed.  As microscopic pieces are ejected from the target material, they create a small amount of thrust that causes the space junk's orbit to change.  Eventually the changes in orbit caused by the ablation of the space debris are sufficient to send the material back into the Earth's atmosphere, where the remainder of the debris will burn up.  Because ablation is only burning enough material to change the orbit of the debris, the overall energy requirements are drastically lower than vaporization, the tradeoff that it will take more time to clear out materials.

Currently there are proposals for both ground and space based laser platforms that could be used for clearing orbit.  According to this NASA paper, a single space based laser would be massive, where the solar panels alone would need to be over 500 meters in diameter to supply the roughly 108 Megawatts of power the laser would require.  At first glance a massive solar array in orbit would seem prohibitively expensive, such a massive undertaking needs a longer-term perspective.  Early in the life of the Anti-Debris Laser System (ADLS), almost all power generated by the solar arrays would be used to clear debris and maintain orbit.  Over the years the volume of debris would begin to drop off and soon our ADLS would have a power surplus and the ability to transmit that energy over a long distance.  The primary debris clearing laser could be augmented by a collection of smaller energy transmitters.  Much as the International Space Station now serves as energy source and orbital platform for a range of experiments, the ADLS could serve both as platform and power source for countless future scientific projects.

One extreme example of the ADLS being used as a remote power source would be for low Earth orbit satellites proposed by the European Space Agency.  These air breathing ion engines are intended to capture the rarified gases that orbit the Earth and use these materials to supply fuel for their ion engines.  A challenge facing current design proposals is the added drag that their solar panels would supply.  If the satellites were designed with the ability to receive additional energy from a directed energy source they would be able to get by with fewer solar panels, which would both reduce the weight of the space craft and reduce drag, a nice little win win.

Future Scenario

April 12th 2051

A new satellite communications start-up has submitted a power purchasing agreement from the United Nations Space Agency's ADLS division.  According to their filing, they are looking to buy sufficient power to supply a constellation of at least 2500 Ultra Low Orbit communication satellites.  These satellites will have some of the lowest orbits ever authorized to a non-governmental body.  In a press release yesterday their spokesbot said "Fastest Trade is looking forward to working with the United Nations Space Agency to help provide 7G Micro Latency communications to the global market of ideas.  Our technology will allow consumers around the world to shave critical nano-seconds off of their communications."  The press release was positively received by several High Frequency firms.  A researcher from the European Space Agency noted that without the external power provided by the ADLS, the orbits of the Fastest Trade satellites would need to be several kilometers* higher than what they have filed for.**

(Scenario 2)

12 hours ago disaster struck Bigelow Research Station El Dorado, due to a series of software errors the station's on board solar panels stopped orienting towards the Sun.  Seven minutes after the error was confirmed support teams from available ADLS platforms were able to add the El Dorado to the orbital power grid user base.  While investigators try to determine how and why the solar panels ceased to function, researchers were able to continue their various projects.  Currently the software team is pointing fingers at an unauthorized 3rd party addition to the solar control platform.

* yeah the scenario is fictional, but I do want to say its on the hard science side of things and the several kilometers value is basically random.  That being said lower drag with a better engine should mean a lower orbit I just don't know by how much.

** honestly high frequency trading is the only reason I can think of  as a long term use for satellites at a really low orbit, that being said I hope there are more generally beneficial uses of this concept.

I hope this idea was interesting, it was inspired by a friend asking me about the potential for using existing satellites and space debris as a source material for future missions.  If you are interested in ideas around re-using old satellites, feel free to check out this post I did a few years ago

Questions and comments are welcome

Make the Dark Side of the Moon Cool (Why We Should Build a Space Elevator on the Moon version 0)

This post will be part of a series, intended to serve as a reference point for how you might potentially write a white paper, in this case on promoting space elevators on the moon, each post in the series will build on the previous document, until the language meets the necessary level of professionalism.  The author asks that readers provide feedback and suggestions for this document.  Who knows maybe someone might actually use the idea.

Every year NASA gets a hyperbole inducing volume of suggestions* for how they should invest their research dollars, ranging from congressional line items, mandating what should be researched over the coming years, letters from school age children making their own suggestions on potential science experiments (like my little brother did when he was in the fifth grade), more seriously are research proposals coming from well reputed scientists working at various research institutes, and once in a while chicken scratch on the back of envelopes and napkins outlining how we really can build the starship Enterprise.  This article hopes to be a bit better than a back of the envelope mission proposal.

A major pain point of any mission sent into space from the planet Earth is minimizing how much mass is required for the mission.  Even relatively massive pieces like the lunar landers used in the Apollo missions where optimized down to the last gram.  As humanity's aspirations to the stars begin to become actual mission plans, those responsible for planning the mission will benefit from having as diverse a portfolio of design and system solutions as possible.  When planning a mission, sometimes engineers can plan on further improvements in technology to save mass, a key example would be the computers that control a space craft, during the Apollo missions, astronauts would brag about a machine that could fit in a single room, that same level of processing power now fits in your cellphone, not only that, the smaller computer requires far less electrical power, continuing a virtuous cycle of design.  Solar panels have also become far more efficient, with panels on satellites converting roughly 40% of the sunlight they are exposed to into useable electricity, compared to 14% in 1961.  Future missions might also benefit from the use of micro-gravity manufacturing techniques, instead of relying on components that must be strong enough to survive the harsh acceleration of gravity, engineers at firms like Made In Space, are producing 3-D printers capable of creating a range of potential space craft components.  These developments are exciting (at least for space and engineering nerds), but they are still relatively limited, because all of these technologies and solutions, need to be launched from the surface of the Earth, what if we had an alternative?  Enter the world of space mining.

The boom of space mining firms like Planetary Resources and Deep Space Industries have sparked imaginations around the world, is humanity finally getting ready to live in the science fiction world's we used to dream about?  Fingers are most definitely crossed.  While mining asteroids for useful materials is exciting and over the coming generations our descendants will most likely be incredibly dependent on industries based around converting asteroids into useful materials there are resources much closer to Earth that should be considered.  The dark side of the moon is a near perfect near to mid-term location for humanity to expand its reach.  The lunar surface has incredibly large volumes of readily accessible oxygen, iron, and aluminum, while there are other resources to gather from the lunar surface, this article is intended to make a case using the most readily available and understood resources.  With access to relatively cheap sources of oxygen for rocket engines, iron for radiation shielding, and aluminum for structural elements, engineers would be empowered to change how they design deep space missions.  Instead of having to launch a probe with all of its fuel, future missions could fill up on oxygen before continuing on to other celestial bodies.  Future space stations would no longer need to launch with complex walls intended to minimize micro-meteorite damage while minimizing mass, instead, tiles of iron could be added to the exterior of the station on an as needed basis.

Outlining cool uses for the basic chemical elements of lunar regolith is all well and good, but how will future missions gain access to the surface of the Moon to use these resources, two words "space elevator".  A space elevator is roughly speaking, a long ribbon of material that has been placed in orbit around a planet or moon, where one end of the ribbon is in contact with the surface, on the other end of the ribbon, there is a counter weight.  The overall length of ribbon is dependent on two characteristics of the celestial body they are built around, the more massive the planet or the slower the day, the longer the tether needs to be.  The pull of gravity also impacts how strong the tether needs to be, on planet Earth you need tether's made out of materials that can, currently, only be made in laboratories in small quantities.  For a tether on the moon the elevator can be made from materials currently available, for example kevlar.  With an operational space elevator on the surface of the moon, future missions to and from the moon would only require sufficient fuel to dock with the space elevator, as opposed to requiring sufficient fuel to safely land on the surface and then fight against the lunar gravity well on the return trip.  Getting to the point where materials are routinely going to and from the surface of the moon will take many years, but might have a timeline as follows.

Phase 0:  NASA and partner organizations request contract bids for companies that will build the first Lunar Elevator

Phase 1:  The first space elevator satellite is deployed on the dark-side of the moon (Pink Floyd album sales experience a light resurgence).  The system is only capable of moving payloads of a few dozen kilograms per container (potentially more, but we are being conservative in estimations)   The small mass flow rate is not considered useful for industrial applications, but allows scientists of partner nations to do far more analysis of the chemistry of lunar regolith

Phase 2:  Improved versions of the initial space elevator probe are now deployed in a constellation around the initial space elevator satellite.  The larger number of probes allow the space elevator consortium to start shipping semi useful quantities of liquid oxygen and other resources.  One client for the liquid oxygen are space mining firms, looking to minimize their launch costs while pursuing asteroids further afield.

Phase 3:  Using the Phase 2 constellation, the Lunar Mining Consortium beings to manufacture their next generation space elevator, this elevator is intended to allow the transportation of thousands of kilograms at a time.   At this point there are multiple small semi-autonomous research stations and mining sites on the dark side of the moon.

Phase 4:  The Lunar Mining Consortium continues to add to the initial space elevator system.  There is a habitat at stationary orbit, serving as a depot and manufacturing facility, where space craft can refuel, receive modifications and exchange crews and/or cargo.  The number of facilities on the lunar surface continue to grow.  A small number of mirrors have been added to reflect sunlight towards various research stations to ensure they receive enough power during the Lunar night

Phase 5:  The elevator has multiple termination points across the lunar surface, including the north and south poles.  The mirrors now ensure that lunar facilities now only require battery power for <10% of the Lunar night.  Lunar manufacturing capacity has reached the point that more than 20% of the material put into space in a given year came from the Moon.  Only organics and more complicated electronics are likely to still launch from Earth in the coming decades.  As a result of the shear volume of materials arriving and departing the Lunar Elevator Station, engineers have added even larger engines and rail guns to preserve the elevator's orbit.

Phate 6:  Using lessons from the Lunar Mining Consortium, humanity forms the Mars Elevator Group, and begins to outline a Martian space elevator, opening up Mars for more ready colonization.

The motivations for developing space mining are quite reasonable, the more materials that can be harvested outside of the Earth's gravity well, the greater flexibility our civilization will have.  That being said there needs to be a dollars and cents argument made to those who hold the strings.  The easiest is for rocket fuel.  for traditional rockets that use hydrogen and oxygen, the oxygen makes up 8/9ths of the mass of the fuel needed (this doesn't include the tanks holding the hydrogen and oxygen).  Now imagine you have a reasonably affordable source of liquid oxygen on the moon.  Now you need way less mass devoted at launch to your liquid oxygen supply.  For crewed missions to Mars that will, potentially, be a massive saving.  Now to developing the space elevator itself, in theory engineers could make a massive rail gun on the surface of the moon, and use that to launch materials into space, true, but the applications are reduced, building a space elevator on the Moon allows scientists to have a  real test bed for space elevator technologies, these technologies could inform how we build a space elevator on Mars and maybe one day the Earth.
The rational behind suggesting the formation of the Lunar Mining Consortium is to promote international collaboration, projects like the ISS have done wonders for promoting cooperation here on Earth, a massive engineering project where dozens of governments can share in innovations and natural resources will hopefully promote a more unified Earth.

Well thanks for reading version 0, feedback and notes are appreciated.

*honestly the author isn't sure how many ideas NASA gets, but assumes it is a lot.

Br(e)aking In Space

A common theme in the planning of deep-space missions(and this blog), is slowing a spaceship down enough to enter into orbit around a particular planet or moon.  As a general rule mission planners at NASA, ESA, and Roscomos need make sure the mission has enough fuel to get their ship going the right speed.  Generally speaking you can slow your ship down using two tools, rocket fuel and the gravity of other planets (I won't try to communicate gravity boosts/br(e)aking because I'm not familiar enough with the concept to do a reasonable highschool physics explanation(use the link if you want to know more)).  What I would like to suggest is a way to augment the rocket fuel option.

One of the many proposals that scientists and engineers have put forth for reducing the cost of launching ships into Earth orbit, is the use of micro-wave lasers (called masers) to help to heat up rocket fuel, the warmer the rocket fuel is, the more energy coming out of the engine's exhaust port.(this is like way over simplifying it).  This is awesome and hopefully sooner than later it will be another alternative way for research satellites to enter orbit (humans may not want lasers pointed at their rocket ship during the near term (personally it would depend on proven safety records of various technologies available), but how does it help us change velocity around other planets.  Short term, not at all.  Looking towards the future, it isn't unreasonable that there will be a relatively steady stream of space probes , and hopefully human explorers, trying to get around the inner solar system.  At that time governments and private bodies might begin to collaborate on creating a network of maser base stations on the larger rocks in the inner system of planets.  Initially the stations would only be placed on our Moon and one of Mars' moons.  Assisting astronauts on their missions to the Red planet and back, as time went on other large asteroids could add these laser arrays to increase mission flexibility.

While I am excited about this idea, that being said it wouldn't be perfect, getting the arrays at the target destinations would not be easy, so probably not a good idea for the first missions.

If engineers and budgets allowed for it, I would try to emphasize the energy beaming system to put out different kinds of power, from visible light to micro-waves.  The larger range of frequencies would allow for different missions to benefit, for space probes returning from the outer planets, the beams could focus additional power for the ion engines, either reducing the needed mass of the solar panels or just overall boosting thrust.  For missions not using ion engines, the focus would be on the use of the maser.

Additional ideas and comments are welcome, thanks for taking the time to read.

*7/26/2016 An edit I wrote break not brake, an observant reader had the decency to inform me of my mistake privately, Sorry 'bout that.

A Thought on Solar Sails

As several posts on this blog have already let on, I am very excited about Breakthrough Starshot.  (the collaboration between Steven Hawking and Yuri Milner into funding research into developing really small spacecraft, that by use of solar sails, would be launched towards Alpha Centauri)  

One of the questions that has been needling away in the back of my mind has been communication back to Earth.  (this question is also a focus for some of the Breakthrough Starshot team's research)  The problem is relatively straightforward, under this mission strategy to get probes to another solar system, you need to make really really low mass probes.  Less mass means less energy necessary to get to really high speeds.  Totally reasonable, the trade off is, the smaller you make the probe, the less space it has for things like, power generation and communication equipment.  The less energy you have to communicate, the harder it is to be heard.  Imagine trying to look for a lightning bug while looking at a massive spot light (this is not my analogy, I took it from a National Geographic story that I semi-recall on the search for exoplanets (alas I don't remember it enough to provide a source right now)).  The lightning bug in this story is our probe, the spot light, Alpha Centauri's stars.  Searching for this lightsource aka, the probes data transmission might just be too crazy, even for our future generation's technology.  

Let us not rely on the amount of signal a single gram of space probe can generate.  There is a beautiful alternative, and it is part of the probe's design, the solar sail.  The solar sail for even an incredibly small probe, would need to be huge, according to wikipedia, a solar sail 800 m by 800 m would produce just over 5 Newtons of force (imagine the amount of effort it takes to pick up a can of soda.  Now imagine you need enough material that when spread out the sail would cover 128 football fields.  That's a lot of area, potentially that is a lot of room for a potentially useful communications tool.  One potential means of using all of that area for a good secondary use, would be to create a material, that for some frequencies of light, it is incredibly reflective, preferably to the color of light that the lasers used to push the probe towards Alpha Centauri would use.  That part is easy, make a substance that is really reflective of one color, the challenge would be this, in addition to reflecting that one frequency of light, it would need the ability to change the frequency of light coming through one side to another on the other side.  Imagine for instance this special material when you shine blue light at it, on the other side yellow light would shine through.  Scientists are already doing work along those lines with materials called quantum dots.  If future researchers are very clever we could make special quantum dots that change one type of photon into another, but only if that quantum dot has been told to.  So now when we shine our blue light at this special material, normally blue light shines through, but when we specially alter that material (think apply a certain voltage, a chemical agent, what have you) now that light is yellow.  (I'm using actual colors for "ease" of communication).

2059 The first Breakthrough Starshot probe begins to fly through Alpha Centauri system, the incredibly small command module begins recording the data that scientists have waited over 25 years for, on its journey through this new solar system.  As the probe gets closer to Alpha Centuari A, systems unused since leaving the inner solar system over 20 years ago begin to activate.  On board controllers initiate a test sequence, confirming that the signalling quantum dots embedded in the solar sail can still convert the star's UV light down to one of A's emissions gaps.  After confirming that the system works, the probe begins to rapidly flicker, alternating between allowing light through unchanged, and emitting downshifted light that astronomers can detect trillions of miles away.

2063  Scientists confirm what had been suspected for years, clear indicators of potential microbial life changing the atmosphere of one of the moons of the Centauri system.

The core concept here doesn't necessarily require that the solar sails only manipulate one small band of the electro magnetic spectrum.  I honestly don't know what the limits would might be.  It could be that the system can alter several energy frequencies, but only be altered one time.  (this still leaves the potential for some simple yes/no messages being sent back)  for example Yes probe 1125 is working correctly and No it hasn't detected some type of organic molecule we associate with life.

Anyways I hope you enjoyed, feed back and questions are always welcome.

A Virtuous Cycle For Rovers on Other Planets

OK I know I promised to start writing posts that were more accessible, but right now I just want to get this idea properly sketched out and for that, I need to use engineerese

First and foremost, I think Curiosity is one of the coolest pieces of hardware that humans have ever built, we have a nuclear powered robot massing in at 900 kg wandering around the surface of Mars, that is effing awesome (if you don't think so I don't know how you got to this blog post).  One of the challenges in the design of Curiosity, or any of the rovers on Mars is having sufficient power to move around.  Currently all of the rovers still active on Mars carry their power supplies with them.  What if instead of carrying their solar panels/nuclear generators , rovers operated similar to how the US Navy uses air-craft carriers and smaller planes, ok not a perfect example.

With this new approach the emphasis on rovers would be mission flexibility, each rover might only come with a small number of sensors and an electrical contact to allow them to receive power from the command pod.  The command pod would most likely carry the bulk of communications, power production(duh), and processing.  The individual probes receiving power from the mothership could be much simpler affairs, with relatively standard parts aside from their specialized sensors.  Each machine would have a very limited amount of on board power storage and production, this would be as a means of redundancy, as well as provide flexibility.   Assume rover A needs to get to a location that is too far away to get to with just its own tether, well rover A and rover B could roll out in the general direction of interest, once B and A have gotten to the maximum distance that their tether will allow, B parks in place, A connected to the mother ship through B, can continue the mission until it gets to the target.  This daisy chaining of mini-rovers could go for a decent amount of distance, of course there would be a limit, either by the number of rovers sent in the mission, or by voltage losses over the distance of transmission.

 There are some inherent trade offs from the maximum area of investigation, to potential mechanical complexity, etc....
The total mass of the mission devoted to all of their little motors will probably be slightly higher than what a larger multi-use rover would use.  You would need to be careful to not let the electrical tethers of the rovers get tangled with other rovers.   This isn't a mission that you do when it still costs $10,000+/kg to get something to Mars, this kind of mission makes sense when launches are 1/10th that (or hopefully less).  As time goes on scientists will want clearer details on areas for future landing sites, governments are going to be interested in quickly confirming whether a region has sufficient resources for larger manned missions.  Smart mission planners would have fall back projects, when the rovers start to fail, the mothership could still do activities, ranging form refining fuel for future missions, to weather research stations,  to acting as a data backup system for orbiting satellites (I know this is a stretch, but who knows).  The Viking probes operated on the surface of Mars for over 6 Earth years, considering Opportunity is still working (12 years passed its original mission length) who knows how long the mothership could do useful science/fuel production.

Any thoughts or alternative approaches are welcome please leave a note.

Riding the Centaur (a long term plan for putting research satellites in orbit around Alpha Centauri)

Stopping when you are going really fast is hard, stopping or slowing down while going really fast while flying through the vacuum of space is really hard, slowing down while going really fast in space without using fuel wicked hard to do.

Breakthrough Starshot, the joint initiative between Stephen Hawking and Russian Billionaire Yuri Milner, discussed in the post Additioanl Uses for the Hawking Milner Interstellar Probes (sorry I didn't know the name of the initiative, if I had studied journalism or writing I would feel far more guilty about the mistake), is currently outlined as a fly-by mission, similar to how NASA's New Horizon spacecraft whipped past Pluto.  As stated before, the faster you're going in space the harder it is to slow down.  For an initiative like Breakthrough Starshot slowing down is probably right out off the table for the first generation of probes, the reason is simple, any fuel the probe would carry with it, would make the mission that much more difficult to get to a useful speed, and the amount of fuel you would need to slow down from .2C, well we won't be doing the math today, but it would be a poop ton (possibly quite literally).  

If mission designer's at Breakthrough Starshot can't use fuel how could they slow down their probes enough to achieve orbit?  

Quick answer, using probes to focus the star light of Alpha Centauri (this will not be as easy as it sounds)

The long answer:  The initial generations of Starshot probes will most likely be relatively simple in design, a large surface area solar sail attached to the actual sensor and communication suite, at least at launch, it seems (to this rather uninformed nerd) unlikely the space craft will try to remain attached to the solar sail once outside of the range of the laser propulsion system.  Why would the probe keep carrying something that can increase the likely hood of colliding with a piece of material that could throw everything off course?  As technology gets better it may become possible to create a solar sail material that can be manipulated in ways similar to how blinds can be manipulated to alter how much light can enter your home.  The ability to create a solar sail that can dynamically alter its shape after deployment would open up a world of possibilities, now the probe can protect their sails across the interstellar void, patiently waiting until the probe gets close enough to its target star and start to put on the breaks.  

(note to self add some drawings 6/1/16, dear readers please remind me to make some artwork)

Alas, as noted before, putting on the breaks when you are going at such extreme speeds would be difficult under even the best of circumstances.  In out solar system sunlight doesn't have sufficient density to provide any real pressure much past the orbit of Mars*.  With Mars having an average distance to the sun of about 1.5 AU, for sunlight to reach Earth at 1 AU it takes 8 min 20 seconds, or 12 min 30 seconds for light to reach Mars' orbit, this means if you are going at 20% the speed of light, that means you have just over an hour to use sunlight to slow yourself down, this makes it unlikely that your probe will sufficiently slow down before burning up.  

But we aren't thinking about the individual probes, Starshot probes are like ants in a colony individually cool but not super effective, but when they work together they can achieve wonderful things.  The probes that are able to control their sails will work together.  A simplified mission profile would look something like this.  Wave A is sent out, they are definitely all going to die horribly, when approaching their target stars, they reconfigure their sails to act as Fresnel lenses, focusing starlight towards those who will come behind them this focused light will increase the amount of breaking force supplied to the probes.  The waves will continue, some waves will be launched with lower initial velocities, the slower you are going when you leave the more time you will have to break on the other side, but it also means you are waiting that much longer to get results.  Eventually you will have a steady string of probes focusing the light of a far off star further and further out, providing a breaking zone for larger probes who come down the line.  Many years after the first wave of probes either burn up in the fires of Alpha Centauri or are left to wander the void beyond, a probe massing a whopping 10 grams slows enough to enter orbit.  This probe left Earth going a mere 5% the speed of light, but has now slowed to a much more manageable 22 km/s to begin its orbit around Alpha Centauri A.  

The advantage of this approach is that all of these probes could be made and launched incredibly cheaply, and if an individual probe is lost, no harm no fowl.

The negative, and it is potentially a big one, it will take at least 80 years for the suggested 10 gram probe to get all of the way to its target destination.  If we don't figure out how to make a space ship that can carry enough fuel to park itself in orbit or some truly sci-fi sounding propulsion method no big deal, humans weren't going to really be heading that way in the near term anyway.  On the other hand, if it turns out we can make some kind of FTL drive, or a fusion powered starship, we suddenly have a rather dangerous traffic jam of dangerous bullets on a potentially intercept course with your ships.  Who knows?

Another version of this idea, will be written about later, which will instead be optimized for helping really really big spaceships get into planetary orbit.

Any suggestions, questions, please leave a comment.

*citation will be added, as of June 1 2016 I am going off of recollection of some research I did.

Making Faster Than Light Travel Safer (for the people at your destination)

The Alcubierre drive is currently considered one of the most plausible means of an intelligent life form creating a faster than light vessel.  Needless to say, this is awesome.  Unfortunately there are some potential risks that come with violently bending the universal speed limit of light.  In rough terms, the way an Alcubierre drive would work involves warping space time.  By expanding space time behind the space craft, while simultaneously contracting space time in front of the vessel, the ship is able to isolate itself from the universe at large and get from point A to point B really fast.  So while this is really awesome, the contracting of space time at the front of the ship has a strong potential to become a rather dangerous weapon, the contracted space time would pull in dust and gases through out the journey, forming a super dense plasma, when space time returns to normal, all of the energy in that plasma is released, potentially fatally for the planets in the star system the ship was trying to visit.
Generally speaking, explorers aren't trying to kill the star systems they are visiting, to prevent the built up energy from being destructive, there are a few options.  One simply aim the ship so that when you stop, you are unlikely to kill anyone with the blast of energy.  Two limit your travels to relatively short hops, minimizing how much energy is built up.  Three (my idea), create a pocket universe in front of your ship.  A group advanced enough to create a faster than light ship, might also be advanced enough to create artificial pocket universes.  These artificial pocket universes could be generated right in front of the ship, providing a temporary storage volume for untold quantities of energy, ideally, the super hot plasma would be stored in the pocket universe where the energy could be slowly let out.  This torrent of energy could assist in allowing the ship to power up when it moves on to the next star system.

Colonizing Alien Planets

If I were part of the planning committee for creating guidelines for colonizing exo-planets here are some of my suggestions for how the colony would be established.

1)  Planning for tomorrow:

          One of the misfortunes Earth has had is our need to mine minerals, the environmental impact of extracting metals from the ground has been substantial.  Colonizing another solar system gives us the opportunity to reduce that potential impact.  Before the colony ships even arrive, robotic mining infrastructure could place a constellation of asteroids in orbit around the target colony world.  Ideally these asteroids would have means of artificially stabilizing their orbits added to them and on a regular schedule minerals would be dropped into a designated mining zone.  Not eliminating the need for mines, but at the very least limiting the number.

2)  Urban Planning:

          Cities on Earth have developed organically over the centuries, this has led our cities to have strange idiosyncrasies in lay out and use of natural resources.  While I wouldn't want to encourage cities to look like depressing grid patterns of identical buildings, we should also aim to avoid city lay outs like Boston, where no one seems to know where streets should connect with each other.  The tv show Tera Nova as short lived as it was, did have an incredibly well thought out first city where the design grew out in a radial pattern, allowing for relatively easy navigation.  Organizations like the Venus Project have cool examples of what these cities might look like.   The goal is not to crush adapting to the local climate, but it is to minimize false starts that we had here on Earth.

.... Taking a break for lunch and enjoying the weekend (1/17/2016)  be back later

Particle Accelerator Engines

This post will be on the shorter end of the spectrum as it is more a personal unanswered question than anything else.

One of the many ways to power spacecraft and satellites is the use of ion engines.

Over the past several years physicists and engineers have been working on making particle accelerators smaller and more energy efficient.  These shoebox sized particle accelerators might serve as a means to augment the capacity of a propulsion system, individual particles, super accelerated could have a very high specific impulse.  Who knows what the ramifications would be for space exploration?

Follow Up 12/2/15:  I wanted to note, part of the challenge of a particle accelerator being used as a means of space craft propulsion is the question of power required per unit of thrust.  There are articles about a seemingly magical drive that some researchers claim can provide something along the lines of a Newton of thrust for a few kilowatts, from a youtube video, which I will need to hunt down, the presenter notes that if a ratio of a few newtons of thrust can be gained by each kilowatt of power put into the engine system, it would revolutionize our ability to explore the solar system.  Under its current design the shoe box accelerator is far from optimized to shooting out a large volume of high speed particles, so first engineers would need to investigate the viability of such a modification from a cost benefits stand point.  If a micro-accelerator can improve the fuel efficiency of space craft the impact could be tremendous, here's hoping we keep solving problems.

Turning the World Right Side Up.... IN SPACE!!!!

One of the many challenges astronauts face while aboard the International Space Station is disorientation.  Basically humans don't really do well when they see things that don't make sense, this includes people working away at a position 90 degrees offset from what they consider the "correct" orientation.  This sense of disorientation has led to crew aboard the space station to temporarily become lost.  There have been several proposals to promote a more consistent sense of direction, this could, at least partially, be handled by painting a consistent up/down color scheme, up is blue, down is brown, something similar to the horizons here on Earth. (honestly I wrote brown without thinking the rhyming was fun, but unintended).  This is a starting point, but assumes that the space craft is built as a borderline plainer structure, something that the ISS is not.  Future space stations are also unlikely to be built in a roughly 2 dimensional configuration, so let us expand this design rational into the 3rd dimension (if you could read this with a dramatic voice that would be awesome).  Future space-craft could use a design reference system that would provide an absolute sense of direction, similar to how naval vessels use the terms, port, starboard, fore, and aft (honestly you really just need more authoritative sounding terms for up and down).  Each direction would have a corresponding color and physical texture.  Seeing as port and starboard already have red and green, respectively, it might as well be worth keeping them as is.  The other colors and textures, I will leave to others to decide, personally I would suggest "up" be a lighter color, "down" to a darker one.  To aid in astronaut's sense of orientation, the inside of buildings here on Earth could also be treated with this coloring and texturing.  Major players  NASA, ESA, JAXA, SpaceX, etc... would need to agree on this design scheme, but in the end, every perspective explorer of the stars could have a shared sense of direction.

Quick note, I can't find the article I read that first talked about using color schemes for orientation, I will try to provide the link at a later time.

Flying Algae IN SPACE!!!!!

Simple fact of life that evolved on Earth, well technically most life that evolved on Earth, and by life I mean animal life, tangents are growing, back on track.  A simple fact of animal life on Earth is that organisms like humans, whales, and nerds all need oxygen to survive.  When we are not on planet Earth, we humans will often use advanced chemistry to filter out carbon dioxide and electrolysis to crack water into hydrogen and oxygen to replace the carbon dioxide that was scrubbed out.  (Honestly the electrolysis thing is surprising to me, before I started writing this piece 10 minutes ago, I sincerely thought we had a chemical approach to at least partially directly recycle the waste gases made by the crew)  This is a problem for long term exploration, if each breath of fresh O2 crew members need to breath in needs to be shipped up, via compressed air or chemically split water, your astronauts are going to be a tad too dependent on home base.  NASA researchers and science fiction authors have put forth a myriad of solutions suggesting ways that plant life could be used to offset at least some of the crews oxygen production means.  Some of my favorites include, specially bred plants with limited musculature that contracts and expands regularly causing air to move (I will try to add a link to the title of the sci-fi novel that has that idea later, found them, book 3 of the Night's Dawn Trilogy* ), in Vernor Vinge's A Deepness in the Sky the author describes a space fairing civilization that ensures that every ship no matter the size has some kind of small garden inside even if it is only a small terrarium, NASA is more pragmatically developing small hydroponic systems to grow lettuce.  My suggestion takes inspiration from all of these ideas, creating a series of small semi-autonomous robotic growth media that are intended to float around the inside of space craft, providing air filtration, visual stimuli, and in emergencies a means to mitigate air from going stale.    

This last detail I will give a little background, actually I won't, after 20 minutes of research it turns out I can't find a link to the story I thought I had read.  The story that I do have is that of Astronaut Jerry Linenger and the Mir 23 crew. During the Mir 23 mission of series of disasters including fires inside of Mir and spacecraft collisions, astronauts and cosmonauts faced a litany of challenges including losing power.  The detail that I thought I remembered, but cannot find a reference to, so this may be just unreliable memory, is that when the Mir crew lost power, they had to manually fan the air around them to avoid CO2 build up.  (if I find the reference I shall add it in, if not well uhh, the false memory served as a source of inspiration)**

Anyways back to the idea, small robotic vehicles with semi-independent power supplies, designed to fly around the inside of a space craft.  One potential version could have the vehicles embedded with special LEDs intended to serve two distinct but equally beneficial uses.  The first is illumination for the plants/algae that grow on the robot, ensuring that the plants have sufficient energy to grow and provide enough clean air. The second feature is to aid in the sleep cycles of crew members, by increasing the relative ratios of red and blue light according to the time of day, astronauts might have an easier time falling asleep.  Roughly speaking, if you increase the amount of blue light people experience in their environment, they are more prone to being awake, if you increase the amount of red light in the environment, people are more likely to feel sleepy.  As plants only really use red and blue light to photosynthesis, it is not that unreasonable to carefully change the light output of the grow lights to accommodate the crew, and the plants, hopefully should not be any worse for the wear.

I hope you enjoy the concept, anyways I should go to bed, if so inspired I shall add conceptual renders down the line, or shitty drawings (the more likely scenario)

*Seriously, I highly recommend reading the Night's Dawn Trilogy, I read the books 10 years ago and many of the ideas have stuck with me.

(12/16/2015)**so i can't find the story about MIR, but someone posted an article on Reddit from the ESA on how astronauts need to sleep next to air ventilation systems to avoid suffocate in their own carbon dioxide.

Storage of mining waste materials

Edit 9/24/15 The better title for this article should have been "Asteroids, the Buffalo of the Final Frontier" (seriously I need to stop with this amateur hour malarkey)
This post is more long term oriented in the overall intent, but it is something we as a society should try to plan for now, better to have basic guidelines now than hope that deep space mining interests will plan for the truly long term.
One of the big risks to astronauts and satellites alike is loose orbital debris whipping around the Earth, causing potential disasters (although not on the same scale as what you may have seen in the movie Gravity.
Currently we have no idea what the waste material from asteroid mining will look like, namely because we don't even have a clear idea on how will extract those resources, as a consequence I will be incredibly vague (shocking I know) as to what said debris will look like, that being said, it is unlikely that the mining process will not create some type of rubble.  Under normal circumstances, the waste material is unlikely to start wandering around the solar system and causing chaos, that being said, in the unlikely event that a mined out asteroid does have a collision with another body or there is some kind of explosion on the mining platform, the cloud of detritus has the potential to cause a laundry list of issues for future space exploration.
Instead of allowing waste materials to be loosely floating around their parent celestial body, mining interests should be required to have a future plan for what to do with their waste mass before mining is allowed to begin.  Depending on the chemical make up of the mining site as well as the type of body being harvested different options will make sense.

One option is to melt waste metallic compounds or glass precursors and use them to bind waste materials into a much larger mass of slagged material.  After the larger mass is created it could be maneuvered via solar sail, laser ablative engine, ion engine, etc.. to a central waste mass reservoir where the waste mass could be refined at a later date when those substances are worth mining separately.  Another potential option is to collaborate with mining and space exploration interests in  the creation of a refining technology that is intended to provide maximum added value for readily available mineral deposits found through out the solar system.

More likely miners would be asked to fill any mining holes with waste material after the completion of resource extraction.  Early mining systems would go for the most obvious resource deposits, harvest as much as financially viable for the extraction system, lift off with a full load of cargo and let future explorers work for more difficult depoits

Changing the Light on a Thousand Worlds (or something)

This idea has been mocking me for completion, on my desktop, for let's say at least 6 months.

Space Exploration is, hopefully, the destiny of the human race and in some distant future we will try to colonize the wider galaxy.  One of the challenges of colonizing other planets is the available sunlight.  Some of the most common stars in the galaxy are red dwarfs, so if we can figure out how to make life around a red dwarf work, you can make colonization work in a large swath of the universe. The reason red dwarfs are potentially difficult to colonize is the amount of energy they radiate.  Unlike brighter stars, including the Earth's yellow sun, red dwarfs burn slowly, releasing the energy of fusing hydrogen and helium over a span of trillions of years.  This rate of energy output means that planets orbiting a red dwarf will be unlikely to receive enough energy to power the engine of an Earth like ecology. 

One potential solution, a modified Dyson swarm. For the uninitiated a Dyson swarm is a massive collection of artificial satellites orbiting a star, capturing as much energy as possible to power the needs of the satellite.  Instead of capturing the energy and locally consuming it, this modified design would redirect the energy of the star towards the planet(s), that is being terraformed.  The means of redirecting this energy are fairly legion, and that is with our current understanding of physics.  The image below gives a really crude example of what that could look like. 

Option 1) simple mirrors:  the name says it all and is pretty straight forward, sunlight hits a specially designed mirror, light is bounced roughly in the direction of the planet. Crude but reasonable.

Option 2) solar power converters, the individual elements of the swarm have solar collectors and some class of light emitter, the satellites capture the energy of the star, the broad spectrum energy is converted into electricity, which then powers some class of laser that aims light at the planet, (said lasers could be mono-chromatic or produce a range of useful light frequencies.

Option 3) Quantum dots.  This idea is similar to Option 2 but more sci-fi.  Quantum dots are cool pieces of material science where the piece captures energy in one part of the electromagnetic spectrum and re-emits that energy at a different frequency, examples include transforming infrared rays into visible light.  (there would probably need to be some mirrors to redirect the light emitted by the quantum dots.

These 3 options are broad categories and only indicate my inferences on possible solutions, others will most likely emerge if this idea is given credence.  

Challenges to this concept are legion, first and foremost, manufacturing and distributing these proposed swarm satellites, followed by how does a civilization guarantee that the satellites they use to ensure that the whole planet doesn't fall back into an ice-age.  

Positives of implementing light directing swarm. 

Multi-planet terraforming:  there are already proposals by engineers and science fiction authors to place arrays of mirrors at the langrangian points of Venus, Earth, and Mars to modify the quantity of solar radiation reaching these bodies with the hopes of regulating climates.  With a fully established swarm of satellites, a civilization bordering on Type 2 classification would have the ability to simultaneously regulate the climates of several worlds as opposed to a new array for each planet that needed to be modified.

Interplanetary trade would be far more feasible with a swarm of light directing satellites.  Depending on the level of sophistication of the swarm a civilization could provide highways of concentrated solar radiation, powering fleets of spaceships propelled by solar sails.

The planning required to produce this kind of swarm would be incredible, realistically building something as mind boggingly massive as a proper Dyson swarm would take centuries, but the benefits to the descendants of those who planned so far into the future would be tremendous.

Another thought before I go.  The nature of this kind of swarm, as opposed to more all encompassing proposals for modifying a star system, would ideally minimally impact the orbital plane that most planets find.  For researchers looking from Earth, I believe we would see the solar radiation of the star heavily modified, appearing compressed with semi-regular modifications to outputs that correspond to planetary orbits.  (honestly I'm talking out my ass here)

Edit 9/25/15:  I really should have re-read the Dyson Sphere entry on Wikipedia, in it they describe a range of designs, and consequently this entry is more of an example of a sub-category of development, that being said I still like the idea.