Mars Climate Orbiter

 1998-073A

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The Mars Surveyor 1998 Orbiter was named the Mars Climate Orbiter. MS98 Orbiter will be launched by Delta 7425 on 10 Dec 1998 onto a Type 2 trajectory. It is built by Lockheed Martin Astronautics, Denver. MCO arrives at Mars in Sep 1999. Mass is 629 kg full, 338 kg dry with 291 kg fuel. Size is 2.1m tall, 1.6m wide, 2.0m deep with 5.5m span. MCO has an equipment module (EM) and a biprop main engine, which is used only for Mars orbit insertion. It will use aerocapture and aerobraking to reach operational orbit.

MS98 will arrive at Mars between Sep 23 and Oct 4. The propulsion engine will fire to place MS98 in a 26 to 36 hr orbit until oxidizer depletion. Aerobraking will then go to sun-synch circular 400 km polar orbit, by Dec 3. The periapsis is over the S pole. The orbiter will serve as a UHF relay for the lander. Two year mapping mission, five year relay mission. The science mission will map the surface at high resolution, and study the distribution of water vapor and ozone. It also will study the transport of dust and water with latitude, the motions of weather systems and dust storms, and study the response to daily solar heating.

PMIRR gives a 5 km resolution vertical profile of temperature, dust, water vapor, and clouds. It also measures the radiative balance of the surface. It has a broadband visible channel and eight channels in the 6 to 50 micron range including high spectral res detectors in the 6.7mu H2O band and the 15 mu CO2 band.

The MARCI WA (wide angle) camera has 5 visible and 2 UV bands, with 7 km resolution in the final orbit. The MA camera has a 40m resolution over a 40 km FOV with ten channels in the visible, 4250A to 1 micron.

A navigation error meant that instead of passing 120 km from the planet, the closest approach was only 60 km. MCO was not heard from after it went behind the planet.

m1/m2 = 629 + 2141/132 = 2770 / 761,

TIP for Dec 10 launch 11.0315 km2/s2, DLA = -142.5576, 14.5768 at 185 km. RA =217.4424, Planned B-plane miss distance was B.R,B.T = (+60000, -60000) km according to the 1996 navigation memo included in the 1997 mission plan databook

MCO
Date	Time	Event	Orbit
1998 Dec 11	1845:51	Launch Delta 7425	CC LC17A
		T+1:03 SRM burnout
		T+1:06 SRM 1-4 sep
		T+4:21 MECO
		T+4:29 Stage 1 sep
		T+4:34 Stage 2 burn
		T+4:45 Fairing
	1857:08	T+11:17 SECO-1	185 x 198 x 28.3
	1924:32	T+38:41 Stage 2 restart
	1924:54	T+39:03 SECO-2	95.53 184 x 905 x 28.4
	1925:47	T+39:56 Stage 2 sep
	1925:24	T+40:33 Stage 3 burn
	1927:52	T+42:01 TECO	185 x -85207 x 28
	1932:34	T+46:43 Yoyo deploy
	1932:38	T+46:48 Stage 3 sep
		T+1h? Solar array deploy
	2005	T+1:20:00 Delta SES-3
	2005	T+1:20:18 SECO-3	95.52 194 x 892 x 24.5
1998 Dec 12	0418	Pass EL1:4
1998 Dec 16	1428?	Depart Earth sphere 1.5Mkm
1998 Dec 21	2133	TCM-1 2.8min 19.1m/s 2.87Mkm
1999 Mar 4	1335	TCM-2 8s 0.9m/s 17.8Mkm to Earth
1999 Jul 25	1200	TCM-3 3.3m/s
1999 Sep 14	1640	TCM-4 15s, 1.4m/s
1999 Sep 19	1617?	Enter Mars sphere 1.082Mkm
1999 Sep 21	0500?	PAM-D enter Mars sphere
1999 Sep 23	0831	Solar array stow
	0849:51	MOI-1 (Leros) 16:23	57 x ? x 90
	0858?	Destroyed?
	0906	MOI-1 cutoff
	0900?	PAM-D pass 83000? km from Mars
		Impact Martian surface
1999 Sep 25	1300?	PAM D depart Mars sphere

Planned post insertion
Date	Time	Event	Orbit
1999 Sep 23	0920	Solar array unstow
		MOI-2 RCS trim 0 to 7 min	160 x 38600 x 90 x 29h
1999 Sep 24		AB-1 MOI+14h Peri lower at first apo	110 x 38600
		Aerobraking
1999 Oct 15		20h, inc trim
1999 Nov 5		10h, inc trim
1999 Nov 19		5 h
1999 Nov 22		End AB	85 x 390
1999 Nov 22		TMO-1 Exit Aerobraking	405 x 437
1999 Nov 23		TMO-2	373 x 437
1999 Dec 1		Mapping orbit, 4PM SSO	373 x 437 x 92.9
1999 Dec 2		Lander Support Mission
2000 Mar 3		Mapping Mission begins
2002 Jan 15		Mars Relay Mission begins

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Payload:

• LEROS engine 640N

• TCM thrusters (4 x 22N)

• MARCI MS98 Mars Color Imager: WA wide angle camera 800m res; MA medium angle camera 40m res, for weather studies.

• PMIRR Pressure modulated IR Radiometer

• UHF Lander comms relay