Moon Lander To Mercury

[Moonguy]

Consider an unmanned lunar cargo lander that delivers 5,000 kg to the lunar surface. The delta-v for landing from a low lunar orbit is 2,100 m/sec. and the Moon's gravity is .16 Earth's.  Now, consider that same lander used to land a payload on Mercury from a low Mercury orbit where the delta-v involved is 3,200 m/sec.  Mercury's gravity is .38 Earth's.  All of the physical characteristics of the lander must remain the same, only the payload mass can be altered.  How much payload must be off-loaded to accomplish the landing?   

Thank you. . . 

[Enthalpy]

You need a little bit more data :

• The Isp of the engine
• The inert mass of the lander

Then, you apply Tsiolkovsky's equation: M_begin / M_end = exp (deltaV / I_sp)
where Isp and deltaV use the same unit, and M includes the inert mass (and the remaining propellant to be accurate).

Landing isn't the big difficulty for Mercury. Arriving on Mercury orbit takes a huge delta V, normally done by many flybys at Venus and Earth. Or you use a better propulsion:
scienceforums and following messages, with a hectares solar sail
My sunheat engine would be good too. A more efficient script meanwhile to leave Earth: scienceforums
Thermal design on Mercury is a huge difficulty too. Better land during nighttime and leave or have finished everything before daytime.