Hazards from the LTV Thruster Exhaust Plume
We have some concerns about the Lunar Transfer
Vehicle's RCS thrusters contaminating the LTV itself as well as its
payload, the Descent Stack. Exhuast from the LTV's hypergolic thrusters
deposit poisons on the outside of the spacecraft, which in turn could be
imported to the pressurized environment on space suits.
For the case of the Space Shuttle, it sounds like NASA is not too worried
about the level of contamination we'll see from the Orbiter pluming the
International Space Station. The primary difference is that the Orbiter
will be arriving at the space station only once every few months, and
its thrusters are aligned to avoid pluming the vehicle it is approaching.
The Orbiter's -Z thrusters in the nose and tail are canted at an angle.
The X vectors cancel each other out giving you a net thrust in the +Z
The Space Station external contamination team has been, is, and will be
assessing all aspects of external contamination induced on-orbit on both
the Internataionl Space Station and the Space Shuttle Orbiter. Included
in these assessments is the effect of Orbiter plume-induced
contamination. Monomethyl hydrazine-nitrate was identified as the
principal contaminant in the Orbiter exhaust.
The assessments to date indicate contamination to be minimal and of
no identifiable concern. These assessments incorporate the latest
experimental results obtained on a recent Shuttle-Mir flight.
So whether this is applicable to the concern about the LTV pluming itself is
still an open question. The LTV still has the risk of pluming itself and its
payload (the landing stack) every time it fires its thrusters. If the LTV
is to spend a long time in orbit and make multiple sorties to the moon, then
we will need assess plume contamination after each flight and consider
methods for keeping the thruster exhaust away from the spacecraft in the
design during the initial design of the vehicle.
Copyright © 2007 Artemis Society International, for the
contributors. All rights reserved.
This web site contains many trade names and copyrighted articles and images.
ASI Web Team
Submit update to this page.
Maintained with WebSite Director.
Updated Sat, May 23, 1998.