196 Asiasat 3 / HGS 1

Nation: Asia Satellite Telecommunications Co. (1)

Objective(s): geostationary orbit, circumlunar mission

Spacecraft: Asiasat 3

Spacecraft Mass: 3,465 kg

Mission Design and Management: Asiasat (operator) + Hughes (design and manufacture)

Launch Vehicle: Proton-K + Blok DM3 (8K82K no. 394-01 / Blok DM3 no. 5L)

Launch Date and Time: 24 December 1997 / 23:19 UT

Launch Site: GIK-5 / Site 81/23

Scientific Instruments: [none]

Results: The lunar flyby accomplished by Asiasat 3 was not part of a science mission but rather the end result of a rescue mission of a satellite that had been stranded in an incorrect orbit. Asiasat 3 was a communications satellite, based on the Hughes HS-601HP bus, launched by the Russians for Asia Satellite Telecommunications Co. Because of the improper second firing of the Blok DM3 upper stage, the satellite ended up in a useless 203 × 36,000-kilometer orbit around the Earth and written off as a loss by Asiasat. Insurance underwriters subsequently signed an agreement with Hughes Global Systems who built the satellite to salvage the vehicle and bring it to its originally intended geostationary orbit by using as little propellant as possible. Using 11 carefully-planned burns beginning 12 April 1998, controllers raised the orbit's apogee to 321,000 kilometers. Then, with the 12th firing on 7 May 1998, the spacecraft was sent on a nine-day round trip around the Moon, approaching as close as 6,200 kilometers to its surface on 13 May. Using this gravity assist, Asiasat 3 hurled back into a usable orbit. By 16 May 1998, perigee had been raised to 42,000 kilometers and inclination reduced from 51° to 18°. A second circumlunar mission began on 1 June that culminated in a 34,300-kilometer flyby of the Moon on 6 June, a distance closer than the Soviet Luna 3. After four more engine firings, the satellite was finally in a 24-hour geosynchronous orbit by 17 June 1998 above 153°. The satellite, now owned by Hughes, was renamed HGS 1. In 1999, HGS-1 was bought by PanAmSat and renamed PAS 22 and moved to 60° W, and subsequently, in July 2002, it was deactivated and moved to a graveyard orbit.

197 Nozomi

Nation: Japan (4)

Objective(s): Mars orbit

Spacecraft: Planet-B

Spacecraft Mass: 536 kg

Mission Design and Management: ISAS

Launch Vehicle: M-V (no. 3)

Launch Date and Time: 3 July 1998 / 18:12 UT

Launch Site: Kagoshima / Launch Complex M-5

Scientific Instruments:

1. Mars imaging camera (MIC)
1. magnetic field measurement instrument (magnetometer) (MGF)
1. electron spectrum analyzer (ESA)
1. ion spectrum analyzer (ISA)
1. ion mass imager (IMI)
1. electron and ion spectrometer (EIS)
1. thermal plasma analyzer (TPA)
1. probe for electron temperature (PET)
1. plasma wave and sounder (PWS)
1. neutral mass spectrometer (NMS)
1. Mars dust counter (MDC)
1. extra ultraviolet scanner (XUV)
1. ultraviolet imaging spectrometer (UVS)
1. low frequency plasma wave analyzer (LFA)

Results: Nozomi, Japan's fourth "deep space" probe, was also its first planetary spacecraft and the first directed to Mars that was not from the United States or the Soviet Union/Russia. The spacecraft was slated to enter a highly elliptical orbit around Mars on 11 October 1999. Its mission was to conduct long-term investigations of the planet's upper atmosphere and its interactions with the solar wind and track the escape trajectories of oxygen molecules from Mars' thin atmosphere. It was also to have taken pictures of the planet and its moons from its operational orbit of 300 × 47,500 kilometers; during perigee, Nozomi would have performed remote sensing of the atmosphere and surface while close to apogee, the spacecraft would have studied ions and neutral gas escaping from the planet. Although designed and built by Japan, the spacecraft carried a set of 14 instruments from Japan, Canada, Germany, Sweden, and the United States. After entering an elliptical parking orbit around Earth at 340 × 400,000 kilometers, Nozomi was sent on an interplanetary trajectory that involved two gravity-assist flybys of the Moon on 24 September and 18 December 1998 (at 2,809 kilometers), and one of Earth on 20 December 1998 (at 1,003 kilometers). The gravitational assist from Earth as well as a 7-minute engine burn put Nozomi on an escape trajectory towards Mars. Unfortunately, a problem valve resulted in loss of propellant, leaving the spacecraft with insufficient acceleration to reach its nominal trajectory. Subsequently, because two more mid-course corrections on 21 December used more propellant than intended, Nozomi's originally planned mission had to be completely reconfigured. The new plan involved four further years in heliocentric orbit, during which time it would conduct two more Earth flybys (in December 2002 and June 2003) leading to a Mars encounter in December 2003, four years after its original schedule. While heading towards Earth, on 21 April 2002, powerful solar flares damaged Nozomi's communications and power systems, causing the hydrazine to freeze in the vehicle's attitude control system. Contact was lost with the spacecraft on 15 May but two months later, controllers found the spacecraft's beacon. Mission scientists were able to thaw the frozen fuel as it approached Earth and the flybys were accomplished as intended: on 21 December 2002 at a range of 29,510 kilometers and once again on 19 June 2003 at a range of 11,023 kilometers. Soon after, the spacecraft's luck finally ran out: on 9 December 2003, in anticipation of the Mars orbit insertion (planned for five days later), the main thruster failed, essentially ending its mission. Instead, ground controllers commanded lower thrust attitude control thrusters to fire to ensure that Nozomi would not impact onto the Martian surface, which would have been a problem since the spacecraft had not been sterilized. The spacecraft passed by Mars at a range of 1,000 kilometers and remains in heliocentric orbit. Despite not accomplishing its primary mission, Nozomi provided important data from its suite of scientific instruments.

198 Deep Space 1

Nation: USA (73)

Objective(s): technology testing, comet flyby

Spacecraft: DS1

Spacecraft Mass: 486 kg

Mission Design and Management: NASA / JPL

Launch Vehicle: Delta 7326-9.5 (no. D261)

Launch Date and Time: 24 October 1998 / 12:08:00 UT

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

Technology Instruments:

1. ion propulsion system
1. solar concentrator array with refractive linear element technology (SCARLET)
1. autonomous navigation system (AutoNav)
1. remote intelligent operations software (Remote Agent RAX)
1. Beacon monitor operations experiment
1. small deep-space transponder (SDST)
1. miniature integrated camera spectrometer (MICAS)
1. plasma experiment for planetary exploration instrument (PEPE)
1. Ka-band solid-state power amplifier

Results: Deep Space 1 (DS1) was designed to test new innovative technologies appropriate for future deep space and interplanetary missions. It was the first in a new series of technology demonstration missions under NASA's New Millennium program. The spacecraft's main goals were to test 12 "high-risk" technologies as ion propulsion, autonomous optical navigation, a solar power concentration array, and a combination miniature camera/imaging spectrometer. As a bonus, the spacecraft also flew by the asteroid 9969 Braille. After a successful launch into parking orbit around Earth, a third stage burn at 13:01 UT on 24 October 1998 put DS1 on a heliocentric trajectory. On 10 November controllers commanded the ion thruster to fire for the first time but it operated for only 4.5 minutes before stopping. Two weeks later, on 24 November 1998, controllers once again fired Deep Space 1's ion propulsion system (fueled by xenon gas) when the spacecraft was 4.8 million kilometers from Earth. This time, the engine ran continuously for 14 days and demonstrated a specific impulse of 3,100 seconds, as much as 10 times higher than possible with conventional chemical propellants. The mission tested its payload extensively to ensure that future users of such technologies would not take on unnecessary risks. DS1 passed by the near-Earth asteroid 9969 Braille at 04:46 UT on 29 July 1999 at a range of only 26 kilometers at a velocity of 15.5 kilometers/second. Although it was the closest asteroid flyby to date, it was only partially successful due to a problem that compromised data delivered to the onboard navigational system. These difficulties prevented a closer encounter, originally planned at 240 meters range. The few images returned from very long range were out of focus although much other data was useful. DS1 found Braille to be 2.2 kilometers at its longest and 1 kilometer at its shortest. Once the successful primary mission was over by 18 September 1999, NASA formulated an extended mission. Originally, the plan had been to have DS1 fly by the dormant Comet 107P/Wilson-Harrington in January 2001 and the Comet 19P/Borrelly in September 2001, but the spacecraft's star tracker failed on 11 November 1999. The continuation of the mission without the use of the star tracker—which initially was thought to be fatal to the mission since the spacecraft could not point its ion engine or sensors in the proper directions—required considerable ingenuity and effort on the part of controllers. Over two months, the operations team struggled to have the spacecraft point its antenna to Earth allowing it to download data on the tracker's failure (as well as other data collected by DS1). Over the subsequent five months, the team devised an innovative plan to revive the vehicle, by "building" a new attitude control system operating without the failed star tracker. Although it was no longer possible to visit the bonus targets (given its limited capability), DS1 was still healthy enough to be targeted to Borrelly with the hope of arriving in September 2001. By the end of 1999, DS1's ion engine had expended 22 kilograms of xenon to impart a total delta V of 1,300 meters/second. On its way to Borrelly, it set the record for the longest operating time for a propulsion system in space. By 17 August 2000, the engine had been operating for 162 days as part of an eight-month run. On 22 September 2001, DS1 entered the coma of Comet Borrelly, making its closest approach of 2,171 kilometers to the nucleus at 22:29:33 UT. Traveling at 16.58 kilometers/second relative to the nucleus at the time, it returned some of the best images of a comet ever as well as other significant data. The spacecraft's ion engine was finally turned off on 18 December 2001, having operated for 16,265 hours and provided a total delta-V of 4.3 kilometers/second, the largest delta-V achieved by a spacecraft with its own propulsion system. By this point, the spacecraft had operated far beyond its planned lifetime and was running low on attitude control hydrazine. A radio receiver was left on in case future contact with the spacecraft was desired, although an attempt in March 2002 to contact the spacecraft was unsuccessful.

199 Mars Climate Orbiter

Nation: USA (74)

Objective(s): Mars orbit

Spacecraft: MCO

Spacecraft Mass: 638 kg

Mission Design and Management: NASA / JPL

Launch Vehicle: Delta 7427-9.5 (no. D264)

Launch Date and Time: 11 December 1998 / 18:45:51 UT

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

Scientific Instruments:

1. pressure modulated infrared radiometer (PMIRR)
1. Mars color imaging system (two cameras) (MARCI)

Results: Mars Climate Orbiter (MCO) was the second probe in NASA's Mars Surveyor program, which also included the Mars Global Surveyor (launched in November 1996) and Mars Polar Lander (launched in January 1999). Mars Climate Orbiter was designed to arrive at roughly the same time as Mars Polar Lander and conduct simultaneous investigations of Mars' atmosphere, climate, and surface. Arrival in orbit was dated for 23 September 1999; MCO would then attain its operational near-circular Sun-synchronous orbit at 421 kilometers by 1 December 1999. The satellite was also designed to serve as a communications relay for Mars Polar Lander. After the lander's mission lasting three months, MCO would have performed a two-year independent mission to monitor atmospheric dust and water vapor and take daily pictures of the planet's surface to construct an evolutionary map of climatic changes. Scientists hoped that such information would aid in reconstructing Mars' climatic history and provide evidence on buried water reserves. After the end of its main mapping mission on 15 January 2001, Mars Climate Orbiter would have acted as a communications relay for future NASA missions to Mars. After launch, the spacecraft was put into a Hohmann transfer orbit to intersect with Mars. It performed four mid-course corrections on 21 December 1998, 4 March, 25 July, and 15 September 1999. At 09:00:46 UT on 23 September 1999, the orbiter began its Mars orbit insertion burn as planned. The spacecraft was scheduled to reestablish contact after passing behind Mars, but, unfortunately, no further signals were received from the spacecraft. An investigation indicated that the failure resulted from a navigational error due to commands from Earth being sent in English units (in this case, pound-seconds) without being converted into the metric standard (Newton-seconds). The error caused the orbiter to miss its intended 140–150-kilometer altitude orbit and instead fall into the Martian atmosphere at approximately 57 kilometers altitude and disintegrate due to atmospheric stresses.

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