* [ This edition was forwarded by the W0RPK-AMSAT Bulletin Board System ] * * [ operating on 515-961-3325 24-hours Ralph Wallio, W0RPK SYSOP ] * Final efforts toward the launch of P3C are underway. Interesting info is starting to appear which I will post in this and following files. Info will be in clumps and dated for future reference. --- Posted: Sat Dec 26, 1987 6:02 AM CST Msg: GGIH-3290-2295 From: AMSATDL To: AMSAT CC: RECOVERY Subj: >>P3C<< GROUND TRACK The following was recently published from ESOC in Darmstadt / West Germany and I thought to put it into this BBS. It shows the subsatellite position and height within the first 8 hours after METEOSAT's separation (including 1st apogee) from the ARIANE-IV launcher. Launch of >>P3C<< is currently to be expected between 1st and 15th April 1988. If all goes well, launch integration in Kourou will start in mid february. 73's and all the best for 1988 de Peter DB2OS ESOC Memorandum ESA/OPS/ECD/OAD/STB/emd; OSCAR-13 Ground track of OSCAR-13: Longitude (deg East), latitude (deg North) & height (km above the Earth's surface) as functions of time (hours & minutes) after separation of Meteosat from Ariane, i.e. 1189 seconds after lift-off. hour min long lat height ---- --- ---- --- ------ 0 0 7.9 -3.6 459. 0 10 45.8 -8.8 2263. 0 20 67.7 -10.0 4771. 0 30 80.6 -9.8 7342. 0 40 88.7 -9.3 9795. 0 50 94.0 -8.7 12089. 1 0 97.6 -8.1 14224. 1 10 100.1 -7.6 16208. 1 20 101.8 -7.1 18053. 1 30 102.9 -6.6 19770. 1 40 103.6 -6.2 21369. 1 50 104.0 -5.8 22859. 2 0 104.0 -5.4 24245. 2 10 103.9 -5.1 25536. 2 20 103.6 -4.7 26737. 2 30 103.1 -4.4 27851. 2 40 102.5 -4.1 28884. 2 50 101.8 -3.8 29839. 3 0 101.0 -3.6 30719. 3 10 100.1 -3.3 31527. 3 20 99.1 -3.0 32265. 3 30 98.1 -2.8 32936. 3 40 97.1 -2.5 33540. 3 50 96.0 -2.3 34080. 4 0 94.9 -2.1 34557. 4 10 93.7 -1.8 34973. 4 20 92.5 -1.6 35328. 4 30 91.3 -1.4 35632. 4 40 90.1 -1.1 35858. 4 50 88.9 -0.9 36035. 5 0 87.6 -0.7 36154. 5 10 86.4 -0.5 36215. apogee number 1 5 15 85.7 -0.3 36223. 5 20 85.2 -0.2 36217. 5 30 83.9 0.0 36162. 5 40 82.7 0.2 36049. 5 50 81.4 0.4 35878. 6 0 80.2 0.7 35648. 6 10 79.0 0.9 35359. 6 20 77.8 1.1 35010. 6 30 76.7 1.3 34600. 6 40 75.5 1.6 34128. 6 50 74.4 1.8 33594. 7 0 73.4 2.1 32996. 7 10 72.4 2.3 32332. 7 20 71.4 2.6 31601. end. Posted: Fri Dec 25, 1987 4:21 PM CST Msg: EGIH-3290-2083 From: JKING To: AMSAT CC: JKING Subj: Orbital Elements for Phase 3-C Several people have been bugging me for the orbital elements issued by Arianespace for the initial orbit of Phase 3-C. Being that it's Christmas and all, I have no further excuses since, I am home and I do have time. So...in accordance with DCI 10/370 20, Issue 2, Revision 1, the following information is provided. There will no doubt be a final update before launch and, of course, an update from the Ariane people after launch. These elements are quite old by now but are probably very close to what is planned. I expect we will receive a telex sometime before launch with the best estimate elements specified. Also included are other useful tidbits related to the injection of the satellite. The elements are not a classical set but most of you know how to proceed with the iformation given. If anyone has problems please let me know. Perigee Altitude: 222.504 km Apogee Altitude: 36,076.636 km Inclination: 9.997 degrees Argument of Per.: 178.148 degrees Ascend. Node Long: -135.541 degrees/lift-off * True Anomoly: 127.554 degrees Epoch: Instant of Separation (L +4797.1 sec.) * Reference is Kourou meridian at lift-off - 9 seconds Remember, we have a long period (3600 sec.) when we remain inside the support structure prior to separation. The elements specified are for the time when we separate from the support cylindrical structure. Normally, one would expect the true anomoly to be near zero at the time of separation from the last stage, however, since we are in the support structure so long we have advanced well away from perigee at the time of our separation when these orbital elements are valid. It is evident from the data given that these orbital elements even take into consideration the separtion velocity given by the springs. The DCI document also gives the one sigma uncertainty of the orbital elements just given. They are as follows: Semimajor Axis: 26.4 km (Apogee ht. + perigee ht.)/2 Eccentricity: 2.9E-4 Inclination: 0.0182 degrees Arg. of Per.: 0.098 degrees Asc. Node Long.: 0.098 degrees The satellite spin rate at the time of separation is: 29.47 degrees/second The separation velocity from the support structure is: 0.590 meters/second The separation unit vectors are as follows: u = -0.0124 v = -0.9368 w = -0.3497 Where: u= Radius vector with its origin at the center of the earth and passing through the intended orbit perigee. v= Perpendicular to u in the intended orbit plane, having the same direction as the perigee velocity. w= Perpendicular to u and v, such that u, v, w form a right handed system. Nutation at separation: <3.2 degrees. Launch Window vs. Launch Date: Not yet provided. Merry Christmas to all and thanks for all your hard work over the past year. I don't know about others but as for me, I'm glad 1987 is just about over. For us, it was the pits. About the only good thing about it was that I feel AMSAT has made big strides to change itself into an organization that can continue to be functional well into the 1990's. We have made some big changes and we will be making more particularly during this next year. Hope everyone will have a nice holiday season. Best Regards and 73's, Jan King & Family, W3GEY Posted: Tue Dec 29, 1987 1:17 PM CST Msg: IGIH-3292-3665 From: MSWEETING To: AMSAT Subj: Real P3c Keps Dumped on 29 Dec 87 19:02:12 Tuesday by ELE093 From: JAMES MILLER G3RUH via MSWEETING Date: 1987 Dec 29 @ 15:00 -------------------------------------- Hello everyone; happy New Year! Many thanks to Jan King for providing us with nominal P3c launch parameters. In case you are having difficulty in converting them to classical keps, below is a program to do it. Its followed by a RUN to give the answers. I thought this format might be preferable to a page of equations and arithmetic. Later changes (my theoretical ESTIMATES only): You will notice a post- launch perigee altitude of 200 km or so, which is too low for comfort. Soon after launch the perigee height will be raised to (say) 1600 km. This is achieved by firing the motor at apogee so as to accelerate from 1590 m/s to 1724 m/s, a "delta-V" of some 134 m/s. If successful this manouevre will change 3 parameters: semi-major axis = 25216 km, eccentricity = 0.6836, and nominal mean motion = 2.168085 rev/d (try it). Later, other motor firing(s) near the ascending node and apogee, approximately perpendicular to the orbit plane will change the inclination from 10 degrees to 60 deg, delta-V = 1460 m/s. [1724*2*SIN(50/2)]. *** In exchange for this science fiction, please can someone give me the spacecraft mass, and motor specification? 100 T$="B.ESA_KEP": REM Convert ESA Launch Data to Keplerian Elements 110 REM 120 REM Version 1.1 Last modified 1987 Dec 29 130 REM 140 REM (C)1988 J.R.Miller G3RUH 150 REM 160 REM Free use encouraged provided credit given to author 170 REM 180 REM Note: RAD(X) is equivalent to PI/180*X, where PI=3.141592654 190 REM DEG(X) is equivalent to 180/PI*X 200 : 210 REM ESA orbital data for P3c (de Jan King, 87/Dec/25) 220 HP = 222.504 :REM Perigee altitude, km 230 HA = 36076.636 :REM Apogee altitude, km 240 IN = 9.997 :REM Inclination, deg 250 WP = 178.148 :REM Argument of perigee, deg 260 LAN= -135.541 :REM Longitude of ascending node relative to Kourou 270 TLAN= -9 :REM .. refered to T_liftoff + TLAN. (deg East, sec) 280 TA = 127.554 :REM True anomaly, deg 290 TE = 4797.1 :REM Epoch time relative to T_liftoff, sec 300 : 310 REM Additional data 320 RV = 0 :REM Orbit Number at TE 330 LK = -52.7016 :REM Longitude of Kourou, deg E 340 REM Constants 350 GM = 3.986E5 :REM Earth gravitational constant km^3/s^2 360 RE = 6378.140 :REM Earth equatorial radius, km 370 GHA0 = 98.8897 :REM Greenwich hour angle at 1988 Jan 0.0, deg 380 WE = 360.9856473 :REM Earth rotation rate, deg/day 390 : 400 PRINT "Please enter time of LIFT-OFF; day, hr, min, sec" 410 PRINT "e.g. 1988 Apr 01 @ 1200 UTC, enter; 92, 12, 0, 0" 420 INPUT DL,HL,ML,SL 430 TL = DL+(HL+(ML+SL/60)/60)/24 :REM Lift_off time, days 440 : 450 A = (HA+HP)/2+RE :REM Semi major axis 460 E = (HA-HP)/2/A :REM Eccentricity 470 N0 = SQR(GM/A/A/A) :REM Nominal mean motion 480 EA = 2*ATN(SQR((1-E)/(1+E))*TAN(RAD(TA/2))) :REM Eccentric anomaly 490 MA = EA-E*SIN(EA) :REM Mean anomaly 500 LAN =LAN + LK :REM Longitude ascending node deg East .. 510 TLAN=TL + TLAN/86400 :REM .. at time TLAN, days 520 GHAA=GHA0 + WE*TLAN :REM GHA (Longitude) Aries at TLAN, deg W 530 RA = GHAA + LAN :REM Right Ascension of Ascending Node .. 540 RA = RA-360*INT(RA/360) :REM .. reduced to range 0 - 360 deg 550 TE = TL + TE/86400 :REM Epoch time, days 560 PRINT 570 PRINT"Nominal Keplerian Elements for P3c" 580 PRINT"----------------------------------" 590 PRINT"Epoch year ",1988 600 PRINT"Epoch time ",TE," days" 610 PRINT"Inclination ",IN," deg" 620 PRINT"R.A.A.N ",RA," deg" 630 PRINT"Eccentricity ",E 640 PRINT"Arg perigee ",WP," deg" 650 PRINT"Mean Anomaly ",DEG(MA)," deg" 660 PRINT"Nom. Mean motion ",DEG(N0)*240," rev/day" 670 PRINT"Decay ",0," rev/d/d" 680 PRINT"Revolution No. ",RV," - " 690 PRINT"Semi major axis ",A," km" 700 STOP RUN Please enter time of LIFT-OFF; day, hr, min, sec e.g. 1988 Apr 01 @ 1200 UTC, enter; 92, 12, 0, 0 ?92,12,0,0 Nominal Keplerian Elements for P3c ---------------------------------- Epoch year 1988 Epoch time 92.555522 days Inclination 9.997 deg R.A.A.N 181.781876 deg Eccentricity 0.730890328 Arg perigee 178.148 deg Mean Anomaly 36.4944488 deg Nom. Mean motion 2.26004464 rev/day Decay 0 rev/d/d Revolution No. 0 - Semi major axis 24527.71 km James 73 G3RUH End of PHASE-3C update 01JAN88 de W0RPK