Background Information about Interplanetary Transport
A rough estimate of bringing a kilogram to low-Earth orbit is 10,000 dollars1. Estimated costs of a manned Mars mission ranges from 20 billion to 450 billion dollars, an uneasy sum to contemplate in the U.S.’s current economy. Why does it cost so much? For one, getting to Mars is no easy feat...
Going the Distance
It’s a long way to the top if you want to go to Mars…
Because Mars’ elliptical orbit is off-kilter to Earth’s, the distance between the two planets is constantly changing. At the closest grouping of the two, Mars and Earth are 56 million kilometers apart (at their farthest, it can be up to 401 million km). Sending vehicles to the Red Planet doesn’t follow the shortest path, however—instead, navigators launch it in the opposite direction, whipping it around the Sun as a the pebble of a “gravitational slingshot” to reduce the amount of propulsion spent. This favorable arrangement of Mars and Earth on opposing sides of the sun occurs once 26 months, and at its fastest still takes 214 days to complete. Compounded, a round trip to and from Mars will take a minimum of nine hundred plus days, Traveling that long, there is also what you have to take along for the ride2.
Heavyweights: Packing for an Interstellar Space Trip
Shipping the supplies for settlement plans directly from Earth to Mars is infeasible by orders of magnitudes. Conventional chemical combustion scales up in the following rough estimates: in order to launch a metric ton of material into low-earth orbit (LEO), it takes about 20 metric tons of fuel and supplies (mT) from an Earth launch pad. In order to send one metric ton of payload to Mars with a propulsion system enough to return to Earth, 180 metric tons from low-earth orbit is required, or 3600 metric tons from an earth launch pad. (As a sense of perspective, that is a seventh of the weight of the Titantic).
Now, for an actual trip, assuming a crew of six astronauts for a manned Mars landing, incredibly speedy 200-day one-way transits and a 560-day stay on the surface, 200 mT in consumables and other life sustaining equipment are needed. If all of these resources are brought along for the ride, the Initial Mass in Low Earth Orbit (IMLEO) would be about 1400 mT, or 28,000 mT from a surface launch pad2. (That, in case you were keeping track, is a full 1.1 times the mass of the Titantic.) As the standard shuttle launch ferries only 125 mT’s equivalent of IMLEO each run, that is roughly a dozen space shuttle launches just to assemble the necessary supplies. Keep in mind that this is just consumables. In addition, there is the problem of fuel for the launch, which often takes up 50% of the total mass .
Is it Worth It?
This is certainly a lot of trouble to go through to land on Mars...you might think, why bother? We’ve approached an entourage of experts in the field and asked them the same question. You can find out what they thought by clicking on the astronaut in the upper left hand corner!
Or, you can journey on, and read about how we hope to make a trip to Mars less costly, more feasible below.
The Case for In situ Resource Utilization
The principle of in situ resource utilization (ISRU) comes from the basic idea to bring as little as possible when visiting other planets. We want to decrease our dependence on home-grown supplies and instead increase our capacity to use the native resources available. Potential benefits of ISRU include significant mass and cost reduction, lowering the barrier for space missions; risk mitigation, as astronauts have more options to deal with emergencies; expansion of the duration and scope of our explorations; and most strikingly, preparation of our eventual capacity to terraform other planets.
Of course, NASA can say it better than we can- see the side for a summary from the ISRU Capability Roadmap published in 2005, outlining four potential areas of benefit for ISRU, as well as 7 elements that would allow these to become possible. The highlighted parts deal with areas that we sought to address in our project. (Color Code: Bright Green: Powercell Yellow: Biocementation 3.
In the case of Mars, after investigating with the resources available, we decided on two essential building blocks: Food and shelter. For the former, we have Project Powercell which sought to imbue new life into the precious carbon building blocks in the atmosphere]. The long term implications are not only the harnessing for sunlight for organic energy consumption, but a revolutionary way to power heterotrophic biological machines: Nutrient Secretion.
What kind of machines are there to power? As a case in point of the power of synthetic biology as the ultimate compact swiss-army knife for the space-farer, we looked at the ability of little known bacteria Sporosarcina pasteurii, and its amazing potential to create literal bricks from nothing more than sand, calcium and nitrogenous metabolic waste*....
*And astronauts, technically, to generate the waste products.
1 Futron Corporation. (2002, September 06). Space transportation costs: Trends in Price per pound to orbit 1990-2000 . Retrieved from www.futron.com/../Whitepapers/Space_Transportation_Costs_Trend]]
2 Coffey, Jeffery. "Distance from Earth to Mars." Space and Astronomy News. Universe Today, 04 June 2008. Web. 24 Sept. 2011. <http://www.universetoday.com/14824/distance-from-earth-to-mars/>.]]
3 Sanders, Gerald B., and Michael Duke, et al. In-Situ Resource Utilization (ISRU) Capability Roadmap Final Report. 19 May 2005. Final Report. NASA/JSC.]]