Between The Moon And Mars

 

People think that humans have conquered the moon. They have done no such thing. The moon fleetingly allowed humans into its domain on nine occasions including six skirmishes to the surface. These skirmishes cleverly and carefully used a fragile spacecraft of limited capability. It could all have gone so wrong while the crew stood on the lunar surface in earth orbit and raised their heads towards the blue oasis above their heads.

To go to Mars humans must leave Earth properly on a trajectory clear of the moon that allows escape velocity to achieve an escape like never before for a twenty four month or more trip. They must steer a course like never before onto a Mars bound solar orbit from which an Apollo 13 style successful failure would surly be a fantasy. When they decelerate into a Mars orbit they will most definitely be on their own in a whole other place. Mission control will be monitoring and advising but will not be remotely close at hand. There will be no oasis above their heads. They must for a time gain acceptance by the barren domain below. To return to Earth they must accelerate to escape velocity out of this whole other place to put themselves onto another long duration solar orbit that will intercept the vicinity of their home planet. Nine trips of up to a week and a half to the local moon most definitely did not qualify humans to do this.

A Mars bound mission might figuratively be said to be three orders of magnitude more difficult representing time, distance and reliability. While noting there is an clear overlap between them, they are each obstacles to survival. Time represents more opportunity for something to go wrong, for a multitude of equipment types to malfunction, for accidents or illness to occur, for natural phenomenon such as solar flares that need to be guarded against or for a long return journey under emergency conditions. Time is an accident waiting to happen. Distance represents the severe isolation of the mission away from the relatively close logistical support of one within the Earth's sphere of influence and also the navigation challenge both in normal conditions or especially with malfunctioning equipment. Reliability represents the challenge of designing long lasting equipment that must undergo complex dynamic function in harsh environments including within a dust prone atmosphere and do so with a limited maintenance capability.

To get to Mars quickly, don't go there...yet. Any mission to Mars carried out in a remotely gung-ho manner is liable to end tragically. There is no fear however that this would actually occur. Sooner or later a few people over a short time or maybe a great many people over a few years would realise “Wait a minute, we can't do this, this won't work, they're all going to...”. There would be a negative backlash against the wasted time and resources and the mission plan would be firmly mothballed. So while a mission to Mars would of course occur it would likely take place at a later point in time than it would if it was approached in a proper manner to begin with. The quickest way to get to Mars is to go to the moon. Go to the moon first and go there properly.

In preparation for a Mars mission humans must return to the moon to learn the art of space exploration. This is regardless of whether they wish to return there anyway for its own purpose. To do this properly involves a lunar program spread over at least a few years from initial footprints and must include multiple extended surface stays each self sufficiently lasting at least a few months with some lasting up to a year or more. This can include overlapping missions either at the same outpost but more ideally at different outposts. Extended surface stay capability must be proven. Surviving on the Martian surface will not be a game. 

Humans must return predominantly to test the humans not the equipment. The specific surface terrain equipment designs for Mars can mostly be better tested on Earth with its atmosphere and Martian like terrains. Mars bound systems such as those for advanced orbital and surface navigation, propulsion and to a certain extent (noting that their temperature ranges are different) advanced and long-term general environmental control can be more realistically qualified on moon missions. Realistic testing of a generally advanced state of technology is a key notion. One important test of equipment on the moon will involve the general ability of pressure suited humans to operate and maintain complex surface equipment for months regardless of its specific purpose and design. In the wider sense it is really the humans who need to be tested in their interaction with advanced off-Earth equipment and surroundings and who need to learn through experience. Things will go wrong and stop working and both the humans and generally advanced technology must be exposed to prolonged realistic conditions to see which designs are inadequate and not as advanced as they were thought to be. The correct answers need to be found for the extended duration survival questions that are currently misjudged. The answers also need to be found for the questions that have yet to be identified.

Simulation of general or more specific operations that can be used on Mars is the objective. Great effort is made to make modern simulations as realistic as possible. Realism is the point. What is the best way to simulate with minimal back-up support, both reliable enclosed environmental control and surface operations such as surveying while utilising general equipment. Simple, do those things on the moon for real. Its the most assured way of testing them in the deep end. If humans are going to go through the motions then they better offset the cost of doing so by actually producing useful results. The moon can be surveyed using ground vehicle sorties for ice and mineral deposits and notably for Helium 3 that can be used for fusion power generation. Such surveying (augmenting satellite analysis) would be very typical of the type of operations carried out on Mars. Also the extent it is carried out at different landing regions to genuinely gain knowledge from the moon would correlate well with the amount of training and experience needed on the moon in preparation for a Mars mission. It's not a choice. This level of experience on the moon is a rational and responsible prerequisite for surviving any practical Mars mission design.

A recurring detrimental factor is when many Mars advocates publicly oppose returning to the moon first. In line with the standpoint of this article, by doing so they are also opposing the removal of barriers to a follow-on Mars mission. Thus their own arguments aren't just arbitrary but in fact harmful to Mars human exploration. Right now the spirit of human space exploration is lost somewhere between the moon and Mars. Mars advocates should consider seriously what they say about a lunar program.

Many people fear that human space exploration will get bogged down mining into the moon instead of progressing to Mars as promised and thus campaign against moon missions. Firstly if the intention is not to engage in more advanced moon operations then...don't. Secondly it would be a big step up from surveying the moon to mining it. There would be no sneaky transition to mining operations that in practical terms could easily take at least two decades to actually get up and running (the 'official' quotes would be several to ten years). In the meantime with the moon surveys largely completed, there would be little reason to be kicking moon dust. With proper operational experience on a local celestial body now gained it could be mission to Mars time.

There was a contradiction that is not appreciated between the ease and difficulty of the Apollo moon missions. The target was astronomically close at hand but no one had had reason to design and build the required technology. By a more rational progression it should not have occurred for at least another decade, say around 1979 and that's assuming there was a will to even do so. It occurred prematurely solely to outdo the Soviets and riskily used a basic spacecraft fueled by gung-ho. This gung-ho additive worked for such a short trip. It would not work for Mars. The problem is that no one has told the public. If NASA had been given a magical money tree back in the day, they would already have off-duty settlers sipping cocktails while looking at a Martian sunset through a panoramic window. It would though have taken far longer than people appreciate because the challenges and development are far greater than people appreciate compared with going to the moon. In the absence of the mythical tree, the rational onward progression for Mars was always something much later than the once quoted turn of the century. The moon mission tanks were topped up by political gung-ho. The Mars tanks are drained by economic reality. You can futilely argue with reality but you will not beat it.

An argument can be made that the lack of a technically realistic Mars mission plan including a lunar program and any intermediate steps, is a principle reason why all such plans have faltered to date. This is in addition to the fiscal challenges. Procrastinating on how to reconcile technical requirements and fiscal realities has wasted both time and money and in doing so has probably caused a subconscious negative backlash against the endeavour. So get it straight upfront and publicly. Completely ignoring cost, the minimal safe requirements of such a mission including all habitable craft deemed necessary must be properly decided upon with input from all relevant quarters. These are independent of any particular conceptual mission plan and are going to be something more substantial than on an unrealistic minimal cost mission. Then drawing up and analysing potential mission plans that fulfil all requirements and allowing for technical development, the time frame that allows fiscal realities to meet the cost demands must be identified. This like it or not will dictate the earliest Mars landing date. At crunch time there is no reliably survivable minimal cost mission, only a minimal requirements mission that must be minimally accepted.

It is believed that the first human landing mission on Mars will in a meaningful sense be initiated and directly overseen from an established Martian orbit. This might not take place until at least several years after humans first reach orbit. More than likely a modular orbiting outpost is foreseen as a departure point, more similar in size and configuration to a small Russian Mir than to the ISS. Clearly it would be extremely costly to get it there in stages but when it comes to the crunch and the challenges and risks of a more imminent landing are better sized up then it is believed that this outpost will be agreed as the necessary way to go. This is weighed against the hazard of planetary approach with direct entry from solar orbit while also targeting a specific localised region with a waiting and vital ascent vehicle and/or long duration habitation modules.

In principal descending to a targeted site from an established orbit ought to be more accurate. A descent vehicle could be pre-placed at the outpost thus simplifying the Mars transit vehicle configuration and propulsion sizing. With Mars launch windows occurring every couple of years, then for the duration of the early Mars landing missions, the post would probably be permanently inhabited from the second crew arrival if not the first. With regard to the landing vehicles and landing crew this more cautious approach comes with the catch of having to decelerate into Mars orbit but this does not rule out aerobraking be it augmented with chemical propulsion. Later landing crews may aerobrake directly into the atmosphere without an orbital stopover with the arrival overseen from either the orbital or a surface outpost. This could become prevalent when actual first hand experience makes descents familiar and more accurate and when targeting more off-plane landing sites. One variation could be a crew arriving at Mars into an independent orbit without an outpost stopover before descending but targeting the outpost when ascending back into orbit.

The orbiting outpost concept affords some distinct advantages. It offers the possibility of a reusable descent and ascent vehicle with on-orbit refueling if required. Later on, surface refueling may fill the tanks for an ascent, de-orbit burn and soft landing. If a parachute system is employed then there is the possibility of repacking them on the surface or else small one-time-use parachute modules can be brought from Earth and attached by the outpost. Either way the descents will also involve heat shield aerobraking. For simplicity in this scenario the initial couple of landings might utilise disposable descent and ascent craft. The orbiting outpost would most significantly provide a long-duration safe haven at all times (the safety net). It would be available if there is a problem with a previously arrived and docked Earth transfer/return vehicle or if the surface base has to be prematurely evacuated. For any ascent it would be a more robust orbital rendezvous target than a singular and possibly unmanned Earth return vehicle. The orbiting outpost could also form a maintainable core element of an orbiting communications relay and also from the outset serve as a crewed science observation platform.

It must be mentioned that it has been proposed as part of the “Flexible Path” (Review of U.S. Human Spaceflight Plans Committee) approach to include Lagrange point navigation, asteroid rendezvous missions and/or a Mars fly-by as possible forerunners to a Mars mission. While carrying out advanced navigation riskily far from Earth the first two also have the relative safety margin of not venturing as far as Mars and also not having to navigate the gravitational well of a planet at deep space range from a solar orbit approach. Respectively taking weeks and months instead of two or more years for a landing, they could certainly be justified as checkpoints on a difficult learning curve. As a mission plan the simpler Lagrange navigation test would be a suitably challenging and recognisable step beyond low Earth orbit providing the public with tangible evidence that exploration is taking place. A configuration including two fully capable earth return and re-entry vehicles could be used (the safety net). While intended as a Mars navigation test, Lagrange navigation is a skill in its own right that space faring humans will need to pick up. The Mars fly-by taking a year seems wasteful without aiming for even a high-orbit insertion. For all the reasons stated in preceding paragraphs the flexible path missions are regarded as valuable intermediate steps but not lunar substitutes. As a vision of where to firstly point near-future human space exploration, simultaneous mission plans for a lunar outpost and Lagrange navigation are recommended that can be implemented in chronological proximity. The focus of this document however is the bigger vision of the moon before Mars and not about intermediate steps.

When the time comes, an initial manned Mars 'orbit' mission in particular could be preceded by the placement of at least core elements of the fore-mentioned orbiting outpost. This outpost and a Earth-Mars crew transfer vehicle could be developed in unison such that their designs share common elements of propulsion, navigation and environmental control. Placing the outpost in Mars orbit could then equate well to an unmanned test run for a subsequent manned Mars orbit mission with a crew transfer vehicle. That mission could target the outpost which in turn could also serve as a safe haven in case of a problem (the safety net). Interchangeability of parts and sub-systems between these two craft to effect repairs should be a design philosophy.

Almost certainly a Mars human mission will be a multinational joint venture. While each participating nations fiscal policies clearly mean that the mission is at least two decades off, it is nonetheless viewed that background technological development could benefit from an Mars international focus organisation made up of interested nations with a space industry and indeed any nation or internationally reputable organisation that can put forward ways in which it might contribute. The organisation could convene at open committee level every one or two years. The intention would be to share opinions and ideas so as to generate better understanding of the challenges and current technology shortfalls. Detailed mission and technological requirements could be identified without focusing on any particular mission design. Participants could see who is already doing what, who has potential in what areas, whose research could be collaborated together and what areas are most lacking in development, etc. The goal would be to pool all developmental resources that they are willing to commit spread over two decades or more. They could reach agreement that certain nations will concentrate on particular developmental areas taking into account current expertise and specialisation. In short they could jointly work over the course of time towards checking all the required boxes and do so with an international focus that simply does not currently exist.

The challenge of going to Mars is the monumental challenge of not having anything significant go wrong far from Earth, every day, week and month for about two years or more. This is a better way of putting it than using inert words like reliability and redundancy that tend to go unheard. As much as many Mars enthusiasts want to cruise on over to the planet ASAP and decelerate down to the surface to a waiting ascent vehicle, it just ain't that neat or easy in a realistically survivable manner. Survivability and reliability on such a long-term remote mission involving complex spaceflight dynamics requires much refined-development and experience of the type that many enthusiasts misjudge to already exist. It is going to take a lot more dedicated effort, money, time and basically experience. To qualify for Mars, go to the moon first and go there properly.

(September 2014)