1994 American crewed spaceflight
STS-68 was a human spaceflight mission using Space Shuttle "Endeavour" that launched from Kennedy Space Center, Florida on September 30, 1994.
Launch.
Launch September 30, 1994, at 7:16:00.068 am EDT from Kennedy Space Center Launch Pad 39-A. The Launch window opened at 7:16 am EDT with a 2-hour-30-minute window. Orbiter mass at liftoff was 247,129 pounds (112,096 kg) including payload. Total vehicle mass was . Payload liftoff mass . Main Engine Cutoff (MECO) was at an apogee of and a perigee of at MET of 8 min 35 s with "Endeavour" traveling at . No OMS-1 burn was required. OMS-2 burn was 1 min 42 s () at MET 33 min.
The launch was originally scheduled August 18, 1994, but there was an RSLS abort at T-1.9 s, after all three main engines ignited – the fifth (and final) time in the shuttle program where an RSLS abort occurred after main engine ignition. Previous aborts occurred on STS-41-D, STS-51-F, STS-55 and STS-51. The automatic abort was initiated by the onboard General Purpose Computers (GPC) when the discharge temperature on MPS Main Engine #3 High Pressure Oxidizer Turbopump (HPOT) exceeded its redline value. The HPOT typically operates at 28,120 rpm and boosts the liquid oxygen pressure from 422 to 4,300 psi (2.91 to 29.6 MPa). There are 2 sensor channels measuring temperature on the HPOT. The B channel indicated a redline condition while the other was near redline conditions. The redline limit to initiate a shutdown is at 867 K. This limit increases to 980 K at T−1.3 s (5.3 s after Main Engine Start). Main Engine #3 (SN 2032) has been used on two previous flights with of hot-fire time and a total of eight starts. This was the first flight for the HPOT on Main Engine (SSME) #3.
A new launch date was set for early October and then moved up to late September. The procedure that has been used on previous aborts treats an RSLS abort after SSME ignition as a launch and to require a complete engine reinspection. A rollback of "Endeavour" to the VAB was done on August 24, 1994. Afterwards, "Endeavour"'s SSMEs were removed and inspected. Three flight certified SSMEs (removed from the "Atlantis" STS-66 mission) were installed on the orbiter and "Endeavour" was rolled back to the launch pad on September 13, 1994. SSME #3 was shipped to the Stennis Space Center in Mississippi for test stand firing over the Labor day weekend (September 5, 1994).
Transatlantic Abort Landing (TAL) sites for the initial launch attempt were Zaragoza, Spain, Moron, Spain and Ben Guerir, Morocco. Abort Once Around landing site was White Sands Space Harbor, New Mexico, USA.
Landing.
Landing October 11, 1994, 1:02:09 pm EDT. Edwards Air Force Base concrete Runway 22. "Endeavour" did an OMS deorbit burn at 12:09 pm EDT about from the landing strip at Edwards Air Force Base. The burn lasted 2 min 17 s which lowered "Endeavour's" velocity . Astronaut John Casper flew the shuttle training aircraft at Edwards and said the weather was clear with light winds. Approach was from the southwest with a right overhead turn of 280 degrees. Nose wheel touchdown at 13:02:21 EDT. Wheel stop at 13:03:08 EDT. Rollout was approximately down the runway. Landing speed at main touchdown was approximately . Orbiter landing mass was . Payload landing mass was .
Landing was originally scheduled for KSC, October 11, 1994, at 11:36 am EDT. The KSC landing attempts on that date were waved off due to cloud cover over the Shuttle Landing Facility.
Mission highlights.
September 30, 1994 (Flight Day 1).
On Friday, September 30, 1994, at 9 am CST, STS-68 MCC Status Report #1 reports: The Flight Control team in Houston gave the "Go for Orbit Operations" just before 8 am. The crew then began setting up the experiment and systems hardware aboard "Endeavour". The primary payload on this flight is the Space Radar Laboratory (SRL-2), making its second flight to study the Earth's environment.
Experiment operations will be conducted around the clock on this flight, with the astronauts divided into two teams. Commander Michael A. Baker, pilot Terrence W. Wilcutt and mission specialist Peter J.K. Wisoff are the "red team". Mission specialists Daniel W. Bursch, Thomas D. Jones and Steven L. Smith are the "blue team".
On Friday, September 30, 1994, at 5 pm CDT, STS-68 MCC Status Report # 2 reports: Shortly after 4 pm that day, flight controllers reported that the on-orbit checkout of the Spaceborne Imaging Radar-C (SIR-C) and the Synthetic Aperture Radar (X-SAR) had been completed, and that the primary SRL-2 instruments were ready for operation. Throughout the checkout, data takes were recorded over a number of sites, including Raco, Michigan; Bermuda; Bebedouro, Brazil; the Northeast Pacific Ocean and the Juan de Fuca Strait, between the United States and Canada.
In addition to the prime payload, Wilcutt also activated the Commercial Protein Crystal Growth Experiment, the Cosmic Radiation Effects and Activation Monitor, and checked on the mouse-ear cress seedlings growing in the CHROMEX-05 experiment. The crew successfully engineered an in-flight maintenance procedure to get additional cooling air to the CPCG apparatus after higher than desired temperatures were noted by crystal growth sensors.
October 1, 1994 (Flight Day 2).
On Saturday, October 1, 1994, at 9 am CDT, STS-68 MCC Status Report # 3 reports: Environmental studies continued throughout Saturday morning aboard Endeavour as six astronauts working around the clock in two shifts assisted the Space Radar Laboratory science team on the ground with real-time observations from space.
While Commander Mike Baker and Pilot Terry Wilcutt made attitude adjustments of the orbiter to assist in precisely pointing the radar systems, Mission Specialist Jeff Wisoff provided running commentary and tape recording assistance for the many ground sites as "Endeavour" passed overhead at an altitude of . The STS-68 mission's three other crew members—Steve Smith, Dan Bursch and Tom Jones—perform the same duties on the opposite shift, beginning at about 4:30 this afternoon.
Late Friday night, Tom Jones sent down some video of a volcano erupting in Kamchatka. The experiment scientists reported the volcano began erupting a couple of weeks ago, but the latest "burst" from the Kliuchevskoi (pronounced clue-chev-skoy) volcano occurred about eight hours after "Endeavour's" 6:16 am launch Friday.
The SRL team is planning a series of data takes using the radar equipment as "Endeavour" moves over that area of the world. Those images will be compared with similar radar images gathered during the STS-59 mission in April, prior to the volcanic activity. Other radar data gathering of the Earth's surface today included the desert regions of Africa, both the Pacific and Atlantic Oceans and mountainous regions of the East and West coasts of the United States.
Early Saturday, Mike Baker sent down a short video tape of smudges and streaks he noticed shortly after launch on several of the forward flight deck windows. None of the streaks would hamper visual observations during entry and landing slated for Monday, October 10.
October 2, 1994 (Flight Day 3).
On Sunday, October 2, 1994, at 9 am CDT, STS-68 MCC Status Report # 4 reports: Radar data gathering today included forest areas of North Carolina, ocean current patterns in the Atlantic and Pacific Oceans, desert areas in Africa, and mountainous regions of the East and West coasts of the United States.
October 3, 1994 (Flight Day 4).
On Monday, October 3, 1994, at 10 am CDT, STS-68 MCC Status Report # 5 reports: "Endeavour's" Space Radar Laboratory equipment continued to search the Earth's land masses and oceans for environmental changes that have occurred since the last SRL mission in April.
The Red Team of Mike Baker, Terry Wilcutt and Jeff Wisoff will be on duty throughout much of the day while the Blue Team of Steve Smith, Dan Bursch and Tom Jones sleeps. Radar data gathering today included much of the East Coast of the United States, current patterns in the Atlantic and Pacific Oceans as well as other bodies of water, desert areas in Africa, and mountainous regions around the world.
Mission Specialist Jeff Wisoff pinpointed storms, lightning and fires and relayed the information to the SRL science team. His observations help correlate and corroborate data collected from the science instruments, including the measurement of air pollution by satellite, which measures carbon monoxide levels in the atmosphere.
Taking such measurements on this flight helps understand changes in the distribution of carbon monoxide as well as other seasonal changes in the environment that have occurred since "Endeavour"'s last mission in April.
On Monday, October 3, 1994, at 5 pm CDT, STS-68 MCC Status Report # 6 reports: "Endeavour's" payload bay cameras sent to Earth dramatic video of the western coast of Oregon and the length of California and the Baja Peninsula that scientists will compare with radar images downlinked from Space Radar Laboratory-2 instruments earlier in the flight. The observations were part of a continuing effort to watch the Earth below for evidence of environmental changes that have occurred since the last SRL mission in April. The overall goal of the mission to better understand the differences in changes caused by natural processes and compare them to changes brought about by human activity. Radar data was recorded today over much of the East Coast of the United States, the Atlantic and Pacific Oceans, Manitoba, Canada, and French Guiana.
Special readings were taken with the Measurement of Air Pollution by Satellite instrument as intentionally set fires were monitored by scientists from the University of Iowa and the Canadian Forest Service. The wind field and thermal evolution of the fires will be analyzed to provide a better interpretation of carbon monoxide emissions from the burning forest and to help calibrate color infrared photography taken by the STS-68 crew. These fires were planned in advance of the mission, and would have been set for forest management purposes even if the shuttle mission were not in progress.
Astronauts relayed information about storms, lightning, fires and clear cutting to the SRL science team that will be used to help understand the radar images and MAPS data on carbon monoxide levels in the atmosphere.
October 4, 1994 (Flight Day 5).
On Tuesday, October 4, 1994, at 9 am CDT, STS-68 MCC Status Report # 7 reports: STS-68 crew members this morning performed two slight maneuvers to fine-tune "Endeavour"'s orbit to mirror its track on the first Space Radar Laboratory mission to support a new experiment called interferometry. The trim burns adjust the orbit to within of where it was in April which will allow scientists to make near identical measurements with the radar equipment to develop a three-dimensional comparison of environmental changes during the six months separating the two missions—STS-59 and STS-68.
On Tuesday, October 4, 1994, at 5 pm CDT, STS-68 MCC Status Report # 8 reports: Space Radar Laboratory-2 scientists adjusted their observation plans to take advantage of an opportunity to train their instruments on the islands of Japan following a Tuesday night earthquake there. "Endeavour" passed over the Sarobetsu, Japan, calibration site about 3:30 pm CDT, and the Synthetic Aperture Radar sent down real-time data of the area below, allowing scientists to look for changes in the coastline of the islands that may have been due to the large tsunami waves associated with the quake. The Spaceborne Imaging Radar also recorded data on the area.
STS-68 crew members continued to perform slight maneuvers to fine-tune "Endeavour"'s orbit to intersect its track on the SRL-1 mission to support a new experiment called interferometry. The trim burns adjusted the orbit to within of where it was in April as it passed over the Mammoth Mountain, Calif., backup supersite. This should allow scientists to make nearly identical measurements with the radar equipment to develop a three-dimensional comparison of environmental changes during the six months separating STS-59 and STS-68.
Radar images over the Sahara desert and the North Atlantic will help scientists evaluate global changes and how they affect the climates in other areas of the world.
Also on October 4, Payload Commander Tom Jones discussed the significance of radar systems and the Earth's environment in an interview with ABC's "Good Morning America". Mission Specialist Jeff Wisoff discussed the mission with CONUS Communications Syndicate affiliates WTKR-TV in his hometown of Norfolk, Va., and the All News Channel in Minneapolis.
October 5, 1994 (Flight Day 6).
On Wednesday, October 5, 1994, at 8 am CDT, STS-68 MCC Status Report # 9 reports: Space Radar Laboratory scientists received some images of Japan, near the location of Monday nights earthquake, but any evidence of the natural disaster was not immediately noticeable. Other radar observations during the