Gargantua2024 wrote:
"So I searched with the official specifications of the ALPACA on the web, but not found anything (yet) "
Indeed nothing usable is published on the performance of the Dynetics lander, or even on the mission profile.
The type of fuel is in discussion, either being LH2/LOX or CH4/LOX. The best data I found is an educated guess on
https://forum.nasaspaceflight.com/index.php?topic=50843.280
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Main ALPACA (launched dry, no drop tanks):
Payload (which is the crew module): 3.1t
Dry mass: 2.4t
...
Isp: 350s
Prop for descent (sub-LLO to surface: 1100 m/s): 4.7t
Prop for ascent (surface to NRHO: 2810 m/s): 6.9t
Single drop tank:
Dry mass: 0.4t (tankage, batteries, COPVs, RCS, docking and methalox lines)
Prop (pre-docking, one tank): 11.6t
Prop (start of descent, one tank): 5.8t
RCS prop (Isp=300s): 0.2t (40 m/s TLI to BLT NRHO)
Both drop tanks, after transferring prop to main ALPACA:
Dry mass: 0.8t
Prop: 11.6t (1730 m/s, NRHO to sub-LLO)
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