STS-59

Int. Designation	1994-020A
Launched	9 April 1994
Launch Site	Pad 39A, Kennedy Space Center, Florida
Landed	20 April 1994
Landing Site	Runway 22, Edwards AFB, California
Launch Vehicle	OV-105 Endeavour/ET-63/SRB BI-063/SSME #1 2028;
	#2 2033; #3 2018
Duration	11 days 5 hrs 49 min 30 sec
Call sign	Endeavour
Objective	Operation of the Space Radar Laboratory (SRL)-1

Flight Crew

GUTIERREZ, Sidney McNeill, 42, USAF, commander, 2nd mission Previous mission: STS-40 (1990)

CHILTON, Kevin Patrick, 39, USAF, pilot, 2nd mission Previous mission: STS-49 (1992)

APT, Jerome “Jay”, 44, civilian, mission specialist 1, 3rd mission Previous missions: STS-37 (1991); STS-47 (1992)

CLIFFORD, Michael Richard Uram, 41, USAF, mission specialist 2, 2nd mission

Previous mission: STS-53 (1992)

GODWIN, Linda Maxine, 41, civilian, mission specialist 3, payload commander, 2nd mission Previous mission: STS-37 (1991)

JONES, Thomas David, 39, civilian, mission specialist 4

Flight Log

In 1991, NASA expanded its many-faceted programme of Earth studies into a global examination of how Earth’s systems (air, water, land and life) interact with each other and affect or influence changes in the global climate. The new programme was designated Mission to Planet Earth and was divided into phases. The initial phase began in 1991, using satellites such as UARS (deployed from STS-48) and dedicated Shuttle missions (such as the ATLAS series) supported by airborne and ground-based studies. Part of this first phase was the Space Radar Laboratory series. Originally a programme of three missions, STS-59 was the first of the eventual two that actually flew.

The primary advantage of radar imaging is the ability to gather data over virtually any region of the Earth regardless of weather conditions. A similar programme was undertaken by the Magellan probe at the shrouded planet Venus. Observational

Mission specialist Tom Jones monitors a number of cameras on the aft night deck which are fixed on targets of opportunity in support of the SRL instruments in the payload bay

imaging radar had been carried previously on STS-2 in 1981 (SIR-A) and STS 41-G in 1984 (SIR-B), and it was the latest variety (SIR-C) that was carried aboard STS-59. The system comprised C-Band (6 cm wavelength) and L-band (23 cm wavelength) radars – four in total – with separate horizontally (H) and vertically (V) polarised units for both bands, and steered electronically. In addition, the mission carried X-SAR, a mechanically-pointed single radar unit (X-band, 3 cm wavelength). There was also an experiment that analysed ocean radar data supplied by SIR-C, as well as MAOS, a carbon monoxide monitoring, sensing and Earth photography package that had flown previously on STS-2 and STS 41-G.

The 7 April launch of STS-59 was postponed for a day at the T — 27 hour mark in order to facilitate an inspection of the metal vanes inside the SSME high-pressure oxidiser pre-burner pumps. The 8 April launch was scrubbed due to bad weather, with low clouds and high crosswinds at the SLF and cloud around the launch pad, but Endeavour launched without incident the following day. Once in orbit, the spacecraft was configured for orbital operations and the crew split into their two shifts, with the Red Shift (Gutierrez, Chilton and Godwin) starting their sleep period and the Blue Shift (Apt, Clifford and Jones) commencing the first series of data gathering. They worked from the aft flight deck as the mission carried no Spacelab or SpaceHab module. After some initial set-up problems, the information came streaming in and was stored on VCR data cassettes. There were 180 such cassettes aboard the Shuttle, enough to support the planned 50 hours of data collection while covering an estimated 50 million square km of the Earth.

This was an international mission, with 49 science investigators and over 100 scientists from 13 nations making up the international science team. The mission focused on the “dry season”, with SRL-2 (STS-68) planned to cover the “wet season” later in the year. This allowed the scientists to compare data from the same sites under different global climate conditions. STS-59 obtained over 133 hours of data (32 terabits, or 32 trillion bits). With SIR-C/X-SAR eventually examining approximately 70 million km of the Earth – representing 12 per cent of the Earth’s total surface and 25 per cent of its land masses – there was enough data to fill 20,000 encyclopaedic volumes. The data-gathering operations were the equivalent of 45 TV stations operat­ing at the same time. Even with advances in digital processing, it would still take five months to process a complete set of images and another nine months of detailed processing after that. At the close of the mission the crew had imaged over 400 sites, including 19 primary observation sites (called super-sites) in Brazil, Michigan, North Carolina and Central Europe.

The crew also found time to work on a variety of secondary and mid-deck payloads and to use the SAREX equipment to talk with both the Russian cosmonauts on Mir and with US astronauts Norman Thagard and Bonnie Dunbar, who were training at TsPK in Moscow. STS-59 also carried three GAS candidate experiments, sponsored by researchers in France, Japan and New Mexico. Perhaps most impor­tantly, the mission also carried the Toughened Uni-piece Fibrous Insulation (TUFI), an improved Thermal Protection System (TPS) tile. Scheduled for a six-flight evalu­ation on all four orbiters, if successful, it was hoped that this fibrous insulation would prove more resilient to impacts in specific areas of the orbiter, such as between the engines, near the landing gear doors and around the orbital manoeuvring thrusters. Several of these new tiles were placed on the base heat shield of Endeavour between the three main engines, for evaluation during the flight and primarily during entry. Post-flight examination revealed no damage on the six tiles installed for the test. The tests ultimately proved successful and TUFI was added to the TPS on the Shuttle from 1996.

Two landing opportunities at Kennedy were cancelled on 19 April due to bad weather. A third chance of bringing Endeavour home to the Cape on 20 April was also waived off, in favour of landing at Edwards.

Milestones

169th manned space flight

92nd US manned space flight

62nd Shuttle mission

6th flight of OV-105

1st flight of SRL payload configuration

1st flight of TUFI – improved thermal protection tile samples