Minimus dV to to a 75x75 LKO orbit

[Nich]

So using the equations from the wiki page https://en.wikipedia.org/wiki/Hohmann_transfer_orbit

I calculated a dV of only 201.2 m/s adding in the velocity to get into orbit at 70m and subtracting the velocity of the surface I get 2452.55 dV. I believe orbital did not add in the circulation dV at 75km

[Red Iron Crown]

My numbers for an airless, infinite TWR, eastward, two-burn ascent to a 75x75km orbit starting from 70m (calculated using the Vis-Viva equation):

"Resting" surface orbital speed (from wiki): 174.5m/s

Periapsis speed for 70m x 75km orbit: 2496.0m/s

Initial burn: 2496.0 - 174.5 = 2321.5m/s

Apoapsis speed for 70m x 75km orbit: 2219.0m/s

Speed for circular 75km x 75km orbit: 2287.2m/s

Circularization burn: 2287.2 - 2219.0 = 68.2m/s

Total delta-V expended: 2321.5 + 68.2 = 2389.7

I believe Orbital Vagabond's numbers are correct (I rounded Kerbin's surface velocity from the wiki to one decimal place and didn't recalculate it for 70m alt, which accounts for the 0.2m/s difference).

[Nich]

I ran the numbers again and you both were correct in my second calculation I think I used 3.3516 instead of 3.5316. UG i need to find my scientific calculator again

[jwenting]

Don't know the exact number, but do know that a craft with a bit over 400 dv left when on the surface of Minmus makes it home to a 30km periapsis on Kerbin with fuel to spare.

Would need more fuel to orbit Kerbin, but I'm usually only concerned with getting it to get home and safely on the ground

[Requia]

The dV required is 3900m/s averagely, can go down to 3300 with PERFECT gravity turn.

Say its 4000 with errors, and then you ll be spending 2750 for getting up to apoapsis with a horizontal velocity of 1000s and burn 1250 to circularise at horizontal velocity of 2250s, thus making 4000 but this is like the worst case scenario

Nah I've done multiple sub 3100 launches with the same vessel to 75x70.

3900 is actually ridiculously high, I never even have more than 3600 including a buffer, 3400 (vac) is my target in design. your TWR is probably really low, which creates inefficiency.