In my attempt to convert vectors to tle I came across RV2TLE_KM.exe More information at: http://sat.belastro.net/satelliteorbitdetermination.com/ Below an example, but now the big question, do these make sense? - input file: P:\>type VEC_KM.TXT -1984.48310589869 -6096.88147152506 2583.05986240779 -0.130403441318205 3.00958857801972 7.002126958 6.97390007195636 - Interactive program and output: P:\>RV2TLE_KM.exe name :VV16 ssn [12345]: 99991 desig [12345A]: 99991A bstar [10000-4]: Enter TLE Epoch Year [2020]: Month [6]: Day [26]: Hour [9]: Minute [49]: Second [8]: VV16 1 99991U 99991A 020178.40912037 0.00000000 00000-0 10000-4 0 6 2 99991 97.3829 254.9647 0071842 12.2389 9.8641 14.94541414 06 [exit] ---- VV16-error 1 99991U 99991A 020178.40912037 0.00000000 00000-0 10000-4 0 6 2 99991 97.3829 254.9647 0071842 12.2389 9.8641 14.94541414 06 VV16-corrected 1 99991U 99991A 20178.40912037 +.00000000 +00000-0 10000-4 0 6 2 99991 97.3829 254.9647 0071842 12.2389 9.8641 14.94541414 06 ---- rv2tle available at https://github.com/cbassa/sattools syntax: rv2tle -i -i -d example: rv2tle -i vec.txt -i 99991 -d 20050A vec.txt syntax: MJD [Modified Julian Date] x y z vx vy vz [km/km/s] example: 59028.14829195195 -1983.2368986279 -6123.14431568009 2521.39798828105 -0.151890429292193 2.94366617210922 7.00212695816602 Modified Julian Date conversion: https://heasarc.gsfc.nasa.gov/cgi-bin/Tools/xTime/xTime.pl?time_in_i=&time_in_c=&time_in_d=&time_in_j=&time_in_m=59028.14829195195&time_in_sf=&time_in_wf=&time_in_ii=&time_in_sl=&time_in_sni=&time_in_snu=&time_in_s=&time_in_h=&time_in_sz=&time_in_ss=&time_in_sn=×ys_in=u×ys_out=u&apply_clock_offset=yes