ESA Document - Emits - ESA

s
Direct Rv Long Rv Short Rv
A1) Very fast transfer
A2) Very small amount of
propellant
RvP RvP
A1) Very secure transfer
A2) High independence
from launch window
A3) Easy crew training
and operational
procedures
A4) Easy abort and re-
trial operations
Figure 4-106: Rendezvous strategies advantages
A1) Balance compromise
between time and fuel
consumption
A2) Very small
uncertainties on
terminal Rv
A3) Independence from
launch window
A4) Easy crew training
Direct Rv Long Rv Short Rv
D1) ∆V V on the terminal RvD
phase are very
demanding
D2) Vf and |V | f| | are a function
of the launch window
D3) Ascent dispersions
increase uncertainty at
RvP
D4)The intercept orbit is also
a function of the launch
window
D5) Crew training very
complex on terminal Rv
RvP RvP
D1) Long time to
rendezvous
D2) High propellant
consumption
D3) Frequent black out
periods
Figure 4-107: Rendezvous strategies disadvantages
HMM
Assessment Study
Report: CDF-20(A)
February 2004
page 370 of 422
RvP
RvP
D1) Relies on high
accuracy sensing sensing
technology
D2) Requires full proven
autonomy paradigms
As it can be seen from the figures, the disadvantages of the direct rendezvous are such that it is
quickly discarded.
The trade-off remains between the long and the short rendezvous strategies.
From the Figure 4-106 it can be mentioned that the short rendezvous technique requires optimal
correction manoeuvres. This strategy is direct targeting the final orbit by introducing several
mid-course correction (MCC) manoeuvres. It has two possible sub-scenarios: to place the MAV
in a low orbit at 500x500 or to place the MAV in a high orbit at 17000x17000 (the Mars geostationary
orbit).