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Getting to Mars: Brief Summary
Requirements:
The basic requirement for the delivery and return spacecraft is that the system be fully capable of transporting
the necessary mission payload to Mars.
Solution Summary:
The first step in designing the Delivery and Return Transport System (DARTS)
will begin with modules being built on Earth. The individual modules
can be sent to Low Earth Orbit (LEO) using Proton rockets and subsequently launched towards
Mars. Proton rockets are Russian liquid propulsion rockets currently
used to launch large payloads. A Proton rocket can carry 20,000 kg, the equivalent of three
elephants, into LEO. However, Protons can only carry 4500kg, two-thirds of an elephant, on
a trajectory to Mars.
Three different packages will be launched: the Communications Package, the Ion
Propulsion Package (IPP), and the Nuclear Propulsion Package (NPP). The Communications Package
will be launched to Mars during approximately the eleventh year of the mission timeline using
three Protons. Once the Communications Package has neared Mars, the satellites will position themselves in geosynchronous
orbits. The IPP modules will be launched to LEO using Protons about year 12, a year after the
Communications Package. The IPP will be made up of a number of individual modules, each propelled
to Mars via a spiral transfer trajectory by their own internal ion propulsion system. The individual
modules will carry scientific equipment, surface robots, and a rover for the martian surface. Each
module will resemble the system used by the Deep Space Probe, launched in the early '90s. The
NPP modules will be launched to LEO using Protons, similar to the IPP launches. The NPP will
contain the Transfer Habitat, the Earth return vehicle, the ascent capsule, and other items that
the astronauts will need on their trip to Mars. The modules will then be assembled through the use
of automatic docking in orbit, similar to the procedure used to dock supplies with the Russian space
station Mir.
The NPP will not be launched from LEO until the IPP is confirmed to be in low Mars
orbit (LMO) and undamaged. Also, the six-member crew will not be sent into LEO until the completion
of the module assembly and testing. Once the Nuclear Propulsion Package
has been assembled and the Ion Propulsion Package has successfully reached Lower Mars Orbit, the
six-member crew will be sent up to the NPP in 2 Soyuz shuttle missions, a cost efficient method for
sending astronauts into space. The Nuclear Propulsion
Package will follow a free-return trajectory that will maximize the safety of the crew.
Uncertainties:
1. The choice of Proton rockets over the more modern Evolved Expendable Launch Vehicle (EELV) series Delta IV Rocket
may or may not be the best choice.
Delta IV rockets are the current rockets being contracted by Boeing. The American-made Delta IV
rockets carry a higher price than the chosen Proton Series. More research will have to be conducted before
it can be concluded that Protons are the absolute best choice.
2. Finding the delta v for the spiral transfer was beyond the scope of the course.
To compensate, the delta v used in calculations was for a modified method of the spiral transfer found
in Caltech's Mars Society's plan to Mars. In their plan,
they also are using a chemical rocket followed by ion propulsion. Hence, their numbers for delta v's will
closely resemble our numbers. But, keep in mind that some of the numbers obtained in our calculations
may not be directly applicable to our situation.
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Copyright © 2000 Massachusetts Institute of Technology