ESA Document - Emits - ESA

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Element 3: Mars Ascent Vehicle
HMM
Assessment Study
Report: CDF-20(A)
February 2004
page 391 of 422
TEMPERATURE REQs [deg C]
Unit Element 3 Unit Name
Quantity Operation Operation NOP NOP
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(max) (min) (max) (min)
1 Docking Mechanism- IBDM 1 50.0 -50.0 100.0 -100.0
2 Electronic Box- IBDM 6 50.0 -20.0 70.0 -50.0
3 Hatch Door- Egress External 2
4 Hatch Door Locking Mechanisms- Egress Externa 2
5 Hatch Door Cont. Protection Cover 1
6 Clamp-band- Stage 1/Stage 2 I/F 1
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ELEMENT 3 SUBSYSTEM TOTAL
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4.5.7 Propulsion
Table 4-63: Thermal Constraints
4.5.7.1 Requirements and design drivers
The payload mass for ascent is estimated 4200 kg.
A thrust of 130 kN is required for the first stage to maintain the T/M ratio at acceptable value
A thrust of 20 kN is required for the second stage to maintain the T/M ratio at the same value
4.5.7.2 Assumptions and trade-offs
The ascent manoeuvre is staged in with two different modules.
Only storable bi-propellant are considered.
No attitude and steering manoeuvres are considered
4.5.7.3 Baseline design 1 st stage
Four improved pump feed version of the AESTUS engine has been chosen as propulsion system
for the first stage.
The engine derives from the AESTUS pressure feed engine used in Ariane-5 upper stage.
Recently this engine was proposed in a pump-feed version with an increase of the Isp
performances and reduced system mass derived from the relaxed pressure tank operating system
typical of pump feed engines.
The engine nozzle has been resized (shortened) for the Martian atmosphere with reduced
performances in Isp and thrust level in comparison to the vacuum performances
The propulsion system presents the following characteristics: