Beyond_Earth-_A_Chronicle_of_Deep_Space_Exploration_1958-2016.pdf

Small Autonomous Stations (MAS):

• 1. meteorology complex (MIS)
• 2. meteorology complex (DPI)
• 3. alpha-particle proton and x-ray spectrometer
• 4. Optimizm seismometer/magnetometer/ inclinometer
• 5. panoramic camera (PanCam)
• 6. descent phase camera (DesCam)
• 7. soil oxidization capacity instrument (MOx)

Penetrators:

• 1. PTV-1 camera
• 2. Mekom meteorological unit
• 3. Pegas gamma-ray spectrometer
• 4. Angstrem x-ray spectrometer
• 5. Alfa alpha/proton spectrometer
• 6. Neytron-P neutron spectrometer
• 7. Grunt accelerometers
• 8. Termozond temperature probes
• 9. Kamerton seismometer
• 10. IMAP-7 magnetometer

Results: Mars 8, the only Soviet/Russian lunar or planetary probe in the 1990s, was an ambitious mission to investigate the evolution of the Martian atmosphere, its surface, and its interior. Originally planned as two spacecraft, Mars 94 and Mars 96, the missions were delayed and became Mars 96 and Mars 98. Subsequently Mars 98 was cancelled leaving Mars 96 as the first Russian deep space mission beyond Earth orbit since the collapse of the Soviet Union. The entire spacecraft comprised an orbiter, two small autonomous stations, and two independent penetrators. The three-axis stabilized orbiter carried two platforms for pointing several optical instruments for studying the Martian surface and atmosphere. After an initial period in low orbit lasting three to four weeks acting as a relay to the landers, the orbiter was designed to spend approximately two Earth years in a 250 × 18,000-kilometer orbit at 101° inclination mapping Mars. The orbiter would have released the two 88-kilogram small autonomous stations (Malaya avtonomnaya stantsiya, MAS), four to five days before entering orbit. The small stations would have landed on the Martian surface, cushioned by an inflatable shell that was to split open after landing. The stations were to have transmitted data daily (initially) and then every three days for about 20 minutes each session. The stations would have also studied soil characteristics and taken photos on the surface. The two 123-kilogram penetrators, each 2.1 meters long, would have impacted the Martian surface at a velocity of 76 meters/second to reach about 6 to 8 meters in depth. The plan was for the orbiter to release them between 7 and 28 days after entering orbit. During their one-year lifetimes, the penetrators would have served as nodes of a seismic network. In the event, the Proton-K rocket successfully delivered the payload to Earth orbit (after the first firing of the Blok D-2 upper stage). Initial orbit parameters were 150.8 × 165.7 kilometers at 51.53° inclination. At that point, the Blok D-2 was to fire once again to place Mars 8 into an elliptical orbit, after which the Fregat propulsion module (with its S5.92 engine) would have sent the spacecraft on a Martian encounter trajectory. The Blok D-2 was to have fired at 10:57:46 UT on 16 November for 528 seconds but either didn't fire or shut down very soon after ignition, thus putting its precious payload into an incorrect and similar orbit of 143.7 × 169.6 kilometers. Mars 8 and its Fregat module then automatically separated from the Blok D-2. The latter seems to have fired (as planned earlier), placing Mars 8 in an 80 × 1,500-kilometer orbit that deposited the planetary probe in Earth's atmosphere, with reentry between 12:30 and 01:30 UT on November 17, probably over southern Chile. Various parts of the vehicle, including 200 grams of plutonium-238, must have survived the reentry although there have been no reports of detection. Mars 8 was scheduled to arrive in Mars orbit on 23 September 1997.

193

Mars Pathfinder

Nation: USA (70)

Objective(s): Mars landing and roving operations

Spacecraft: Mars Pathfinder

Spacecraft Mass: 870 kg

Mission Design and Management: NASA / JPL

Launch Vehicle: Delta 7925 (no. D240)

Launch Date and Time: 4 December 1996 / 06:58:07 UT

Launch Site: Cape Canaveral Air Force Station / Launch Complex 17B

Scientific Instruments:

Pathfinder Lander:

• 1. IMP imager for Mars Pathfinder (including magnetometer and anemometer)
• 2. atmospheric and meteorology package (ASI/MET)

Sojourner Rover:

• 1. imaging system (three cameras)
• 2. laser striper hazard detection system
• 3. alpha proton x-ray spectrometer (APXS)
• 4. wheel abrasion experiment
• 5. materials adherence experiment
• 6. accelerometers

Results: Mars Pathfinder was an ambitious mission to send a lander and a separate remote-controlled rover to the surface of Mars, the second of NASA's Discovery missions. Launched one month after Mars Global Surveyor, Pathfinder was sent on a slightly shorter seven-month trajectory designed for arrival earlier. The main spacecraft included a 10.5-kilogram six-wheeled rover known as Sojourner capable of traveling 500 meters from the main ship at top speeds of 1 centimeter/second. The mission's primary goal was not only to demonstrate innovative, low-cost technologies, but also to return geological, soil, magnetic property and atmospheric data. After a 7-month traverse and four trajectory corrections (on 10 January, 3 February, 6 May, and 25 June 1997), Pathfinder arrived at Mars on 4 July 1997.

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The spacecraft entered the atmosphere using an atmospheric entry aeroshell that slowed the spacecraft sufficiently for a supersonic parachute to deploy and slow the package to 68 meters/second. After separation of the aeroshell heatshield, the lander detached, and at about 355 meters above the surface, airbags inflated in less than a second. Three solid propellant retro-rockets reduced velocity further (firing about 100 meters above the surface) but were then discarded at 21.5 meters altitude—they flew up and away along with the parachute. The lander-within-the-airbag impacted on the surface at a velocity of 14 meters/second generating about 18 g's of acceleration. The package bounced at least 15 times before coming to rest, following which the airbags deflated revealing the lander. Landing time for Pathfinder was 16:56:55 UT on 4 July 1997 at 19° 7′ 48″ N / 33° 13′ 12″ W in Ares Vallis, about 19 kilometers southwest of the original target. The next day, Pathfinder deployed the Sojourner rover on the Martian surface via landing ramps. Sojourner was the first wheeled vehicle to be used on any planet. During its 83-day mission, the rover covered hundreds of square meters, returned 550 photographs and performed chemical analyses at 16 different locations near the lander. The latter meanwhile transmitted more than 16,500 images and 8.5 million measurements of atmospheric pressure, temperature, and windspeed. Data from the rover suggested that rocks at the landing site resembled terrestrial volcanic types with high silicon content, specifically a rock type known as andesite. Although the planned lifetime of Pathfinder and Sojourner were expected to be one month and one week respectively, these times were exceeded by 3 and 12 times respectively. Final contact with Pathfinder was at 10:23 UT on 27 September 1997. Although mission planners tried to reestablish contact for the next five months, the highly successful mission was officially declared over on 10 March 1998. After landing, Mars Pathfinder was renamed the Sagan Memorial Station after the late astronomer and planetologist Carl Sagan. In 2003, Sojourner was inducted into the Robot Hall of Fame. On 21 December 2006, NASA's Mars Reconnaissance Orbiter's HIRISE camera photographed the flood plain of the Ares and Tiu outflow channels; images clearly showed the Pathfinder and associated hardware.

194

ACE

Nation: USA (71)

Objective(s): Sun–Earth L1 Lagrange Point

Spacecraft: ACE

Spacecraft Mass: 752 kg

Mission Design and Management: NASA / GSFC

Launch Vehicle: Delta 7920-8 (no. D247)

Launch Date and Time: 25 August 1997 / 14:39 UT

Launch Site: Cape Canaveral Air Force Station / Launch Complex 17A

Scientific Instruments:

• 1. solar wind ion mass spectrometer (SWIMS) and solar wind ion composition spectrometer (SWICS)
• 2. ultra-low energy isotope spectrometer (ULEIS)
• 3. solar energetic particle ionic charge analyzer (SEPICA)
• 4. solar isotope spectrometer (SIS)
• 5. cosmic ray isotope spectrometer (CRIS)
• 6. solar wind electron, proton, and alpha monitor (SWEPAM)
• 7. electron, proton, and alpha-particle monitor (EPAM)
• 8. magnetometer (MAG)
• 9. real time solar wind experiment (RTSW)

Results: The Advanced Composition Explorer (ACE) spacecraft was designed to study spaceborne energetic particles from the Sun–Earth L1 libration point, about 1.4 million kilometers from Earth. Specifically, the spacecraft was launched to investigate the matter ejected from the Sun to establish the commonality and interaction between the Sun, Earth, and the Milky Way galaxy. In addition, ACE also provides real-time space weather data and advanced warning of geomagnetic storms. ACE's nine instruments have a collecting power that is 10 to 10,000 times greater than anything previously flown. After launch, the spacecraft's Delta 2 launch vehicle's second stage reignited (after 4 hours) to insert the satellite into a 177 × 1.37 million-kilometer orbit. After reaching apogee a month after launch, ACE inserted itself into its Lissajous orbit around the L1 point. The spacecraft was declared operational on 21 January 1998 with a projected two- to five-year lifetime. As of early 2015, it continues to provide near-real-time 24/7 coverage of solar wind parameters and measure solar energetic particle intensities. With the exception of the SEPICA instrument (data from which was no longer received after 4 February 2005), all instruments on ACE remain operational as of mid-2017, and the propellant on board could theoretically allow a mission until about 2024.

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195

Cassini-Huygens

Nation: US and ESA (3)

Objective(s): Saturn orbit, Titan landing

Spacecraft: Cassini and Huygens

Spacecraft Mass: 5,655 kg

Mission Design and Management: NASA / JPL / ESA

Launch Vehicle: Titan 401B-Centaur (TC-21 / Titan 401 no. 4B-33)

Launch Date and Time: 15 October 1997 / 08:43 UT

Launch Site: Cape Canaveral Air Force Station / Launch Complex 40

Scientific Instruments:

Cassini:

• 1. cosmic dust analyzer (CDA)
• 2. visible and infrared mapping spectrometer (VIMS)
• 3. imaging science system (ISS)
• 4. radar
• 5. ion and neutral mass spectrometer (INMS)
• 6. radio and plasma wave spectrometer (RPWS)
• 7. plasma spectrometer (CAPS)
• 8. ultraviolet imaging spectrograph (UVIS)
• 9. magnetospheric imaging instrument (MIMI)
• 10. dual technique magnetometer (MAG)
• 11. composite infrared spectrometer (CIRS)
• 12. radio science subsystem (RSS)

Huygens:

• 1. atmospheric structure instrument (HASI)
• 2. gas chromatograph neutral mass spectrometer (GC/MS)
• 3. aerosol collector and pyrolyzer (ACP)
• 4. descent imager/spectral radiometer (DISR)
• 5. surface science package (SSP)
• 6. Doppler wind experiment (DWE)

Results: The Cassini-Huygens project was the result of plans at NASA dating from the early 1980s and formally approved in 1989 as a joint NASA-ESA mission. Having survived several attempts by Congress to cancel the mission, the mission that emerged was a cooperative project with ESA (as well as the Italian Space Agency, ASI) involving a NASA-supplied spacecraft, Cassini, that orbits Saturn, and an ESA-supplied lander, Huygens, which descended into the atmosphere of Titan, Saturn's largest moon, in 2005. ASI provided the high-gain and low-gain antenna assembly and a major portion of the radio system. The primary scientific goals of the mission included a diverse set of investigations of Saturn, its moons, and its near environment. The 3,132-kilogram orbiter with an original design life of 11 years was powered by three radioisotope thermoelectric generators (RTGs), of the same design as the RTGs carried aboard Ulysses, Galileo, and New Horizons.

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The 335-kilogram Huygens, named after the Dutch physicist Christiaan Huygens (1629–1695), was designed to investigate Titan's atmosphere's chemical properties and measure wind, temperature, and pressure profiles from 170 kilometers down to the Moon's surface. The probe was not designed to survive past landing although scientists did not rule out the possibility entirely. Cassini's trip to Saturn included four gravity assists. Seven months after launch, the spacecraft passed Venus on April 26, 1998 at a range of 284 kilometers, gaining 26,280 kilometers/hour. Cassini performed a second flyby of Venus on June 24, 1999 at a range of 623 kilometers and one of Earth at 03:28 UT on 18 August 1999 at a range of 1,171 kilometers, before heading to Jupiter. During this portion of the traverse, Cassini passed by the asteroid 2685 Masursky on 23 January 2000, flying as close as 1.5 million kilometers at 09:58 UT.