ESA Document - Emits - ESA

s
Inclination (deg)
47.5
47
46.5
46
45.5
The total dV is143.5 m/s.
Master and Flyer Inclination Evolution
Master
Flyer
45
0 2000 4000 6000
Time (s)
8000 10000 12000
4.5.2.4.1.1 Intermediate rendezvous
Figure 4-109: Inclination evolution
HMM
Assessment Study
Report: CDF-20(A)
February 2004
page 373 of 422
After any plane change, the chaser is at 50 km below the target and at 140 km behind it. A
Hohmann transfer is executed to move the Orbiter towards the MAV, from a point 20 km behind
the target and in V-bar (see Figure 4-110).
For the intermediate rendezvous, a trade-off was mad between several substrategies:
• To place the MAV above and ahead drifts backwards towards the target
• To place the MAV below and behind drifts in front of the target
• To place the MAV below and ahead drifts the MAV in from of the orbiter
Finally, the last substrategy was selected: To place the MAV below and ahead. It is a quick
transfer based on Shuttle guidance to ISS docking port that has very good manual backup
features.
After the Hohmann manoeuvre, a tangential transfer in V-bar is executed to place the chaser 1
km ahead of the target maintaining it still in V-bar.
At that point a station keeping is commanded and a series of test start. These hold points will
allow the astronauts to verify the authorisation to proceed for the next phase. The hold point is
expensive in terms of fuel. It accounts for for the following tasks:
• Checking out subsystems.
• Occurrence for the sub-solar angle: Earth-orbiter-Sun angle more than 5 degrees.
• Communication with Earth for the ATPs (Authorisation to Proceed) to the next point.