Development of a Cold Gas Propulsion System for the ... - SSL - MIT

propulsion tasks will be grouped and defined. There are two basic methods of doing this. One way is to
separate lift (i.e. support of the vehicle’s weight) from attitude control. The other is to devote some lift
to fractional weight relief, so that the effect of Earth’s gravity on the testbed is effectively reduced to
that of the Moon (or other target body), and to combine the remaining lift with attitude control to
simulate the entire propulsion system that will be used on the actual lander. The second major decision
is whether the two tasks will be performed by entirely separate propulsion systems, or whether there
will be a single propulsion system with two separately-controlled sets of actuators.
Lunar lander testbeds have been built and
flown with all four possible combinations
of these divided propulsion architecture
options. In fact, TALARIS took inspiration
for its architecture from the Apollo
program’s Lunar Landing Research Vehicle
(LLRV, Figure 2-2) and its successor, the
Lunar Landing Training Vehicle (LLTV).
These vehicles used a gimbaled turbofan
jet engine for 5/6 weight cancellation and a
system of hydrogen peroxide rockets to
simulate the Lunar Module propulsion,
which they did with great success; Neil
Armstrong credited his successful lunar
landing, as well as those of his fellow
Apollo astronauts, in large part to
Figure 2-2. Lunar Landing Research Vehicle (LLRV) in
flight, 1964 [8].
extensive training on the LLRV and LLTV [9]. However, because they were designed to carry a human
pilot, the LLRV and LLTV were much larger than TALARIS. Several more recent robotic lander simulation
vehicles provide a closer comparison to TALARIS.
24