1975-075A
The Viking A (Lander 2/Orbiter 2) payload was hurriedly replaced by Viking B (Lander 1/Orbiter 1) on the pad at Cape Canaveral in Aug 1975 because of a battery problem, after an initial countdown scrub on Aug 14.
The Titan Centaur took off on 1975 Aug 20 at 2122 and inserted Viking 1 into solar orbit. TC-4's insertion predicted closest Mars approach at 1976 Jun 20 2319 UTC at a distance of 32227 km (T=164486, R=-277133). After blowdown
A mid course correction on 1975 Aug 28 set course for Mars. Approach burns AMC1 and AMC2 were made on 1976 Jun 10 and Jun 15, with Mars orbit insertion on Jun 19. The MOI-1 burn on Jun 21 refined the orbit to 24.66h, 1513 x 32625 km x 37.9 deg, with periapsis at 23.2 deg latitude. MOT5 trim burn on Jul 9 and MOT6 on Jul 14 synchronized the orbit over the landing site. The lander was separated on Jul 20. The bioshield base was jettisoned into Martian orbit.
A trim burn on Aug 3 was followed by MOT7 on Sep 11, starting a drift orbit 21.88h, 1491 x 29510 km x 38.1 deg, with periapsis at 30.8 deg. On Sep 20 the orbit was synchronized again over the VL2 site. MOT 9 on Sep 24 trimmed the orbit.
The Viking Extended Mission began on 1976 Dec 14. Viking Orbiter 1 (VO-1) was used to study the Martian moon Phobos. MOT10 on 1977 Jan 22 put VO-1 on a Phobos approach orbit. On Feb 4 and 12 the MOT11, MOT12 burns synchronized the orbit with that of Phobos. On Feb 20, VO1 made a flyby of Phobos at a distance of 88 km.
Further MOT burns were made over the next few months including MOT15 to avoid Phobos and MOT16 to perform a radio occultation experiment. A series of experiments flying through the shadow of Phobos were carried out on Sep 20, 23 and 27.
The Viking Continuation Mission began on 1978 May 31 and lasted until 1979 Feb 26 when the Deep Space Network was required for the Voyager encounters. MOT17 on 1978 Dec 2 put VO1 in a slow walk, at 24.85h 260 x 34088 km x 39.9 deg, with a periapsis at 38.5 deg south latitude. VO1 reached its lowest periapsis of 234 km on 1979 Jan 22.
The Viking Survey Mission began on 1979 Jul 19, and was replaced by the Mapping Completion Mission on Nov 6. The MOT20 burn on 1979 Nov 6 moved the periapsis latitude to -4.7 deg. The Survey II mission lasted from 1980 Apr 23 to 1980 Jul 14, and on Jul 15 VO1 began the Termination Phase. Test burns on Jul 15-18 were followed by a propellant depletion burn on Jul 31. The last images were taken on 1980 Aug 5 and VO-1 was turned off on command at 2000 on 1980 Aug 7.
| VO1 | |||
| Date | Time | Event | Orbit |
|---|---|---|---|
| 1975 Aug 20 | 2122:00 | Launch by Titan IIIE | |
| 2123:40 | Heat shield jettison | ||
| 2123:51 | Stage 1 burn | ||
| 2124:01 | SRM sep | ||
| 2126:19 | Stage 1 MECO | ||
| 2126:20 | Stage 1 sep | ||
| 2126:20 | Stage 2 burn | ||
| 2126:32 | CSS fairing sep | ||
| 2129:40 | Stage 2 MECO | ||
| 2129:54 | Stage 2 sep | ||
| 2130:06 | Centaur MES 1 | ||
| 2132:11 | Centaur MECO 1, 19 min coast | 158 x 165 x 29.21 | |
| 2147:33 | Centaur MES 2 | ||
| 2152:48 | Centaur MECO 2 | ||
| 1975 Aug 20 | 2156:31 | Centaur sep | 183 x -50629 x 29.3 |
| 2158:42 | Solar panels deploy | ||
| 2210:41 | Centaur retro | ||
| 2214:52 | Centaur retro cutoff | ||
| 1975 Aug 20 | 2329:00 | Bioshield cap sep | |
| 1975 Aug 21 | 0505? | Leave EL1:4 | |
| 1975 Aug 21 | 0549? | Centaur leave EL1:4 | |
| 1975 Aug 24 | 1220? | Leave Earth sphere | |
| 1975 Aug 24 | 1457? | Centaur leave Earth sphere | |
| 1975 Aug 27 | 1.00120 x 1.66788 x 4.48 | ||
| 1975 Aug 27 | 1830:11 | MC1 targeting 4.6m/s 12s 6kg | 1.00121 x 1.66898 x 4.48 |
| 1975 Sep 6 | 2010 | Post MC1 periapsis | |
| 1975 Sep 6 | 2039 | Pre MC1 periapsis | |
| 1976 Sep 17 | Mass 3464 kg | ||
| 1976 Jun 9 | He leak discovered | ||
| 1976 Jun 10 | Approach | 1773 x -20117 x 36.44 | |
| 1976 Jun 10 | 1100 | AMC1 3464 kg, 60 kg used, 50.5m/s 122.4s | |
| 1976 Jun 10 | Approach | 2113 x -20918 x 38.44 | |
| 1976 Jun 15 | 1400 | AMC2 3404 kg, 70 kg used, 60.0 m/s 143s | |
| 1976 Jun 15 | Approach | 2164 x -21518 x 38.01 | |
| 1976 Jun 17 | 1130 | In Mars SOI | |
| 1976 Jun 19 | 2220:43 | MOI 37:49 1.097 km/s | |
| 1976 Jun 19 | 2258:32 | MOI cutoff | 42.4h 1514 x 50300 x 37.7 |
| 1976 Jun 21 | 1726:21 | MOT1 80.0m/s | 24.66h 1513 x 32625 x 37.9 23.2 |
| 1976 Jul 9 | 0040:00 | MOT5 25.7m/s 41s out of sync | |
| 1976 Jul 14 | 0712:00 | MOT6 2.7m/ssync over 47W | |
| 1976 Jul 20 | 0832:15 | Sep from VO1 | |
| 1976 Jul | Bioshield base sep | ||
| 1976 Aug 3 | 0300:00 | SKT-2 burn 2.2m/s, stationkeep with VL1 | |
| 1976 Sep 11 | 1903:54 | MOT7 21.3m/s | 21.88h 1491 x 29510 x 38.1 30.8 |
| 1976 Sep 20 | 2215:29 | MOT8 3.7m/s | |
| 1976 Sep 24 | 1510:00 | MOT9 22.9m/s | |
| 1976 Dec 14 | Viking Extended Mission | ||
| 1977 Jan 22 | MOT10 Phobos sync | 23.05h 1480 x 30856 x 39.1 38.1 | |
| 1977 Feb 4 | MOT11 Phobos trim | 23.05h | |
| 1977 Feb 12 | MOT12 Phobos trim | 23.05h | |
| 1977 Feb 13 | P236 Phobos-1 174 km | ||
| 1977 Feb 14 | P237 Phobos-2 159 km | ||
| 1977 Feb 15 | P238 Phobos-3 153 km | ||
| 1977 Feb 16 | P239 Phobos-4 157 km | ||
| 1977 Feb 17 | P240 Phobos-5 153 km | ||
| 1977 Feb 18 | P241 Phobos-6 127 km | ||
| 1977 Feb 19 | P242 Phobos-7 103 km | ||
| 1977 Feb 20 | P243, Phobos-8 flyby 89 km | ||
| 1977 Feb 21 | P244 Phobos-9 104 km | ||
| 1977 Feb 22 | P245 Phobos-10 137 km | ||
| 1977 Feb 22 | P246 Phobos-11 174 km | ||
| 1977 Feb 23 | P247 Phobos-12 194 km | ||
| 1977 Feb 24 | P248 Phobos-13 204 km | ||
| 1977 Feb 25 | P249 Phobos-14 213 km | ||
| 1977 Feb 26 | P250 Phobos-15 225 km? | ||
| 1977 Feb 27 | P251 Phobos-16 255 km? | ||
| 1977 Feb 28 | P252 Phobos-17 290 km? | ||
| 1977 Mar 11 | MOT13 | 21.92 299 x 30750 x 39.2 | |
| 1977 Mar 24 | MOT14 | 23.50 303 x 32540 x 39.3 | |
| 1977 May 15 | MOT15 Phobos avoidance | 23.50h 323 x 32520 x 39.2 36.8 | |
| 1977 Jul 1 | MOT16 | 23.97h 321 x 33050 x 39.2 32.7 | |
| 1977 Sep 20 | Phobos shadow pass | ||
| 1977 Sep 23 | Phobos shadow pass | ||
| 1977 Sep 27 | Phobos shadow pass | ||
| 1978 May 31 | Viking Continuation Mission | ||
| 1978 Oct 19 | Possible Phobos pass, 612 km | ||
| 1978 Dec 2 | MOT17 | 24.85h 260 x 34088 x 39.9 -38.5 | |
| 1979 Feb 26 | DSN to Voyager | ||
| 1979 May 19 | MOT18 | 24.99 329 x 34148 x 39.9 -29 | |
| 1979 Jul 19 | MOT19 | 24.79h 357 x 33925 x 39.9 -20.0 | |
| 1979 Jul 19 | Viking Survey Mission | ||
| 1979 Nov 6 | MOT20 | 23.95h 351 x 32997 x 38.0 -4.7 | |
| 1979 Nov 6 | Mapping Completion Mission | ||
| 1980 Apr 19? | MOT-21 951 kg 15 m/s | 24.52h 369 x ? x 38.9 | |
| 1980 Apr 23 | Survey II Mission | ||
| 1980 Jul 15 | Termination Phase | ||
| 1980 Jul 15 | Test | 36.36h 373 x 47857 x 37.7 31.9 | |
| 1980 Jul 17 | Test | 41.82h 375 x 51038 x 37.5 31.8 | |
| 1980 Jul 18 | Test | 47.56h 351 x 56273 x 36.9 31.2 | |
| 1980 Jul 31 | Depletion | 47.63h 411 x 56275 x 37.9 31.7 | |
| 1980 Aug 7 | 2000 | Turned off | |
Payload:
- Vidicon cameras (0.48m telescopes)
- IR radiometer 0.05m telescope A, 18-24 mu; 0.05m telescope B 9.8-12.5mu; 0.05m telescope C 6-15mu; 0.025m telescope D with 0.3-3mu bandpass.
- IR spectrometer
VL-1 (Viking Lander 1) landed on Mars on 1976 Jul 20. The VL has both deorbit engines and braking engines, built by RRC. The Aeroshell Base contains the four RCS deorbit engines, with two fuel tanks mounted on the aeroshell itself; the engines are monopropellant hydrazine with Isp = 160s. The three terminal descent (TD) engines on the lander are 2.7 kN thrust each. An upper atmospheric mass spectrometer is mounted on the aeroshell and returns data from 7000 to 100 km altitude.
On 1981 Jan 7 Viking Lander 1 was renamed the Thomas A. Mutch Memorial Station in honor of a member of the VL-1 team (1931-1980) who had been killed in a climbing accident. It returned its last image on Sol 2238, 1982 Nov 5, and stopped transmitting on 1982 Nov 13.
| VL1 | |||
| Date | Time | Event | Orbit |
|---|---|---|---|
| 1976 Jul 20 | 0832:15 | Sep from VO1 | |
| 0839:16 | S+7:01 Deorbit 23 min burn 156m/s | ||
| 0901:35 | S+29:20 Deorbit complete | ||
| 1135:08 | Orient for entry | ||
| 1144 | Alt 245 km | -100 x 30828 x 37.9 | |
| 1144:08 | S+3:11:53 Entry 243.8km 4.6098 km/s -16.99 deg | ||
| 1151:06 | S+3:19:02 Parachute deploy 5.9 km | ||
| 1151:13 | Aeroshell base sep 5.0 km | ||
| 1151:25 | Legs deployed | ||
| 1151:25? | Aeroshell top sep | ||
| 1152:19 | Terminal descent 1.5 km | ||
| 1153:05 | Touchdown LT=19min | ||
| 1159 | Biology PDA lid deploy | ||
| 1976 Jul 22 | 0719 | Arm cover eject | |
| 1976 Jul 23 | 1138 | GMCS lid deploy | |
| 1976 Dec 14 | Viking Extended Mission | ||
| 1980 Aug 7 | Lander Monitor Mission | ||
| 1981 Jan 7 | Renamed Mutch Memorial Station | ||
| 1982 Nov 13 | End of transmissions? | ||
| 1982 Nov 20 | End of operations | ||
| 1983 Jun | Mission ended | ||
Payload:
- SNAP-19 RTG
- Itek facsimile cameras
- TRW biology unit
- XRFS X-ray flourescence spectrometer
- GCMS Gas Chromatograph Mass Spectrometer
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