bi-elliptic transfer calculator

--------------INPUT PARAMETERS--------------------------------------
GM = 3.5316e12 --body's standard gravitational parameter
startalt= 100000 --burn's start altitude
endalt = 2875000--butn's end altitude
elliptictransferalt=8400000 --bi-elliptic transfer burn apoapsis
-------------CODE FROM BELOW ON-------------------------------------

hohmannSMA = (startalt+endalt)/2
ellipticstartSMA = (startalt+elliptictransferalt)/2
ellipticendSMA=(endalt+elliptictransferalt)/2

startvel=math.sqrt(GM*((2/startalt)-(1/startalt)))
hohmannvelpe=math.sqrt(GM*((2/startalt)-(1/hohmannSMA)))
hohmannvelap=math.sqrt(GM*((2/endalt)-(1/hohmannSMA)))
endvel=math.sqrt(GM*((2/endalt)-(1/endalt)))

--print(startvel, hohmannvelpe, hohmannvelap, endvel)
print("Hohmann transfer burns:",hohmannvelpe-startvel, endvel-hohmannvelap)
hohmanntotaldv= (hohmannvelpe-startvel)+(endvel-hohmannvelap)
print("Total delta-v for Hohmann transfer:",hohmanntotaldv)


ellipticvelstartpe=math.sqrt(GM*((2/startalt)-(1/ellipticstartSMA)))
ellipticvelstartap=math.sqrt(GM*((2/elliptictransferalt)-(1/ellipticstartSMA)))
ellipticvelendap=math.sqrt(GM*((2/elliptictransferalt)-(1/ellipticendSMA)))
ellipticvelendpe=math.sqrt(GM*((2/endalt)-(1/ellipticendSMA)))

print("Bi-elliptic transfer burns:", ellipticvelstartpe-startvel, ellipticvelendap-ellipticvelstartap, ellipticvelendpe-endvel)
bielliptictotaldv=(ellipticvelstartpe-startvel)+ (ellipticvelendap-ellipticvelstartap)+(ellipticvelendpe-endvel)
print("Total delta-v for bi-elliptic transfer:",bielliptictotaldv)

print("Bi-elliptic transfer requires "..bielliptictotaldv/hohmanntotaldv.."x delta-v compared to a Hohmann transfer with given input parameters.")