STS-90 (90)

Columbia (25)
Pad 39-B (41)
90th Shuttle Mission
25th Flight OV-102
Ascent OMS Burn (2)

NOTE: Click Here for Countdown Homepage


Richard A. Searfoss (3), Commander
Scott D. Altman (1), Pilot
Richard M. Linnehan DVM (2), Mission Specialist
Dafydd Rhys Williams MD (1) (CSA), Mission Specialist
Kathryn P. Hire (1), Mission Specialist
Dr. Jay C. Buckey (1), Payload Specialist
Dr. James A. Pawelczyk (1), Payload Specialist

Alternate Payload Specialists -
Dr. Alexander W. Dunlap (0), Alternate Payload Specialist
Dr. Chiaki Mukai (1) (NASDA), Alternate Payload Specialist


OPF3 -- 12/05/97 (Reference KSC Shuttle Status 12/05/1997)
VAB3 -- 03/16/98 (Reference KSC Shuttle Status 3/16/1998)
PAD -- 03/23/98 (Reference KSC Shuttle Status 3/23/1998)
TCDT -- 03/30/98 (Reference KSC Shuttle Status 3/30/1998)


Neurolab, GAS(G-197, G-467, G-772)

(Reference KSC Shuttle Status Dec 1997)
(Reference KSC Shuttle Status Jan 1998)
(Reference KSC Shuttle Status Feb 1998)
(Reference KSC Shuttle Status Mar 1998)
(Reference KSC Shuttle Status Apr 1998)
(Reference KSC Shuttle Status May 1998)

Mission Objectives:

Click here for Additional Info on STS-90

Neurolab is a Spacelab module mission focusing on the effects of microgravity on the nervous system. The goals of Neurolab are to study basic research questions and to increase the understanding of the mechanisms responsible for neurological and behavioral changes in space. Specifically, experiments will study the adaptation of the vestibular system and space adaptation syndrome, the adaptation of the central nervous system and the pathways which control the ability to sense location in the absence of gravity, and the effect of microgravity on a developing nervous system.

The mission is a joint venture of six space agencies and seven U.S. research agencies. Investigator teams from nine countries will conduct 31 studies in the microgravity environment of space. Other agencies participating in this mission include six institutes of the National Institutes of Health, the National Science Foundation, and the Office of Naval Research, as well as the space agencies of Canada, France, Germany, and Japan, and the European Space Agency.


Launch April 17, 1998 2:19 p.m. EDT. Launch window was 2 hours, 30 minutes. The crew had breakfast and departed the Operations and Checkout Building (O&C) for the pad at 11:02 a.m. The crew arrived at the Pad 39-B and began ingress at 11:18a.m. Hatch closeout was performed by 12:35 EDT and cabin leak checks were completed at 1:17 EDT. At 1:49pm EDT, the countdown clock came out of the planned hold at the T-minus 20 minute mark. At 2:10pm EDT, the countdown clock came out of the T-minus 9 minute mark. Liftoff occured on time at the start of the launch window. The only ascent problem was with some ice buildup in the Water Spray Boiler system. Weather officials predicted a zero percent chance that weather would prohibit launch activities. The forecast called for few clouds at 3,500 and few clouds at 25,000 feet; visibility of at least 7 miles; winds from the south at 12-20 knots; a temperature of 83 degrees F and relative humidity of 55 percent. (Reference KSC Weather History 04/17/1998 1400).

On Thursday, 4/16/98, at 8:15am, the launch of Space Shuttle Columbia on mission STS-90 with Neurolab was postponed 24 hours earlier today due to difficulties with one of two network signal processors (NSP) on the orbiter. Mission managers first noticed the problem at about 3 a.m. during normal communications systems activation prior to tanking operations. As a result, work to load the external tank with the cryogenic propellants did not begin. The NSPs, which are located in the orbiter's middeck, format data and voice communications between the ground and the Space Shuttle. Both processors are required for launch and landing and are also highly desirable for on-orbit mission operations. The unit which failed, NSP No. 2, has at this time been removed and replaced. Testing of the new unit is scheduled to be completed this evening. The countdown clock has been reset to the T-11 hour hold position and will remain there until 11:59 p.m. (Reference KSC Shuttle Status 4/16/1998)

Middeck animal holding lockers containing 18 pregnant mice and 1514 crickets were removed at the pad. A middeck biotechnology technology locker was also relocated to provide access to the defective NSP. In the event the launch cannot be done on 4/17/98, the Neurolab payload will require a 96 hour scrub turn around to reinstall and resupply experiments, including 135 snails, 152 rats and 233 fish.

On Wednesday, 4/15/98, Neurolab late stow activities were completed early in the morning and closeouts of the spacelab and airlock were conducted soon afterwards. Activation of Columbia's communications systems began in the afternoon. RSS rollback was complete by about 8:30pm. Efforts to load the external tank with 500,000 gallons of liquid oxygen and liquid hydrogen were scheduled to begin at about 5:30 a.m. (Reference KSC Shuttle Status 4/15/1998)

On Monday, 4/13/98, the launch countdown for mission STS-90 began on time at 2 a.m. KSC managers are working no major issues at this time and launch preparations continue on schedule for lift-of on Thursday. Columbia's aft compartment closeouts are complete and replacement/reload of mass memory unit No. 1 concluded over the weekend. Vertical stowage of the flight crew systems is in work and the first of three Neurolab late stow waves begin this afternoon. The STS-90 flight crew arrived at KSC's Shuttle Landing Facility at 3:30 p.m. today. They will participate in crew equipment fit checks, routine medical examinations and fly in the Shuttle Training Aircraft in the days leading up to launch. (Reference KSC Shuttle Status 4/13/1998)

On Wednesday, 4/8/98, Columbia's prelaunch preparations continued on schedule with the launch countdown slated to begin early Monday morning. Orbiter aft compartment closeouts are proceeding very well and will conclude Saturday. Payload early stow activities are nearing completion today in the orbiter's cargo bay. Ordnance installation begins later today following final inspections of the right forward booster integrated electronic assembly. (Reference KSC Shuttle Status 4/08/1998)

On Friday, 3/27/98, Launch pad validations were completed except for orbiter midbody umbilical mating activities, slated for the first week in April. Main engine ball seal leak checks were completed 3/26/98 and helium signature leak testing occured. Purging of the gaseous nitrogen (GN2) lines on the mobile launch platform and cleaning of a GN2 panel continued through the weekend. NASA managers may opt to open Columbia's payload bay doors on Monday to give technicians access to two bolts on a getaway special canister. If the work is needed, technicians will add a washer to each bolt to ensure that the bolts are properly secured. The doors will be closed again on Tuesday. The minor unplanned work will not impact the launch date. (Reference KSC Shuttle Status 3/27/1998)

On Monday, 3/23/98 at about 7:30 a.m. the Shuttle began its 4.2 mile trip to launch Pad 39B atop th crawler transporter and arrived at Pad 39B at about 3:20 p.m. At about 7 p.m., the Rotating Service Structure (RSS) was extended around the Shuttle (Reference KSC Shuttle Status 3/24/1998)

On Friday, March 20, 1998, Columbia's Shuttle Interface Test was successfully concluded. (Reference KSC Shuttle Status 3/23/1998)

On Monday, March 16, 1998, Columbia rolled over to the VAB. (Reference KSC Shuttle Status 3/16/1998)

On Thursday, March 12, 1998, work on Columbia's right inboard elevon was completed and both forward and aft compartment close-outs were in work. Tomorrow, technicians will complete work to install the aft doors. Aft compartment structural leak tests will follow. (Reference KSC Shuttle Status 3/12/1998)

On Monday, 3/2/98, The Neurolab transfer tunnel has been mechanically and electrically mated and the tunnel interface verification test was completed on Friday. Space Shuttle main engine close-out operations and leak checks are complete. Main engine heat shields are being installed and a landing gear functional test is scheduled for today. In the Vehicle Assembly Building, the external tank was successfully mated to the solid rocket boosters on Thursday. (Reference KSC Shuttle Status 3/02/1998)

On 2/26/98, work to install the Space Shuttle Main Engines (SSME's) were complete. The STS-90 crew participated in the crew equipment and interface test (CEIT) and a sharp edge inspection of the orbiter's crew module and Neurolab. (Reference KSC Shuttle Status 2/26/1998)

On Thursday, 2/5/98, installation of Columbia's airlock hatch "D" was completed. The hatch provides access from the tunnel adapter to the Spacelab transfer tunnel. On Friday, 2/6/98, functional tests on Columbia's airlock hatch "D" and inspections of micrometeorite hits on the orbiter radiator and checklife support system were completed. Aft compartment closeouts and payload premate testing continued. Technicians proceeded with main engine heat shield rework efforts. The Neurolab payload is scheduled to arrive at the OPF on Wednesday (2/11/98) for installation into the orbit's cargo bay and the Shuttle main engines will be installed on Thursday. (Reference KSC Shuttle Status 2/06/1998)

On Monday, February 2, 1998, replacement of a relief valve on Columbia's auxiliary power unit No. 2 and water spray boiler checkout were completed. Leak checks on the Spacelab water line are also completed and work on payload bay flood light No. 3 continued. Tunnel adapter flow rate leak testing and airlock ducting reconfiguration were also in work. (Reference KSC Shuttle Status 2/02/1998)

On Monday, January 12, 1998 Technicians completed removal of Columbia's window No. 6 yesterday and installed the new window on 1/13/98. Replacement of floodlights No. 1 and No. 5, in the orbiter's payload bay was in work as well as aft flight deck reconfiguration. Fuel cell voltage tests and checks of the flash evaporator system were also scheduled. (Reference KSC Shuttle Status 1/13/1998)

On Monday, January 5, 1998, Shuttle Columbia's payload bay doors were opened yesterday to accommodate Ku band antenna testing yesterday afternoon. The orbiter's nose and main landing gear tires were also installed yesterday. Orbiter maneuvering system testing and replacement of fuel cells No. 1 and 3 are in work. Window polishing efforts begin tomorrow and inspections of the forward reaction control system are scheduled for Friday 1/9/98. (Reference KSC Shuttle Status 1/08/1998)

Orbiter Thermal Protection System (TPS) Tile damage was found on Columbia following its inspection after STS-87 landed on 12/5/97. 99 tile removals are planned with 40 tile removals under evaluation.


Altitude:150 nautical miles
Inclination: 39 degrees
Orbits: 256
Duration: 15 days, 21 hours, 50 minutes, 58 seconds.
Distance: miles


ET : SN-91
MLP : 2
SSME-1: SN-2041 (HPOTP 8013, HPFTP 6110)
SSME-2: SN-2032 (HPOTP 4211, HPFTP 2128)
SSME-3: SN-2012 (HPOTP 6209, HPFTP 4117)


KSC May 3, 1998 12:09 p.m. EDT Runway 33. Landing Groundtracks for the 1st KSC landing opportunity took the shuttle over southern Mississippi and Alabama. Sonic booms heard at KSC at 12:05pm EST as Columbia approached. Main Gear Touchdown 15 days 21 hours 49 minutes 59 seconds. (12:08:59 EST) Nose Gear Touchdown 15 days 21 hours 50 minutes 13 seconds. (12:09:13 EST). Wheels Stop 15 days 21 hours 50 minutes 58 seconds. (12:09:58 EST).

Meteorologists are forecasting favorable conditions at the Kennedy Space Center on Sunday for a landing at 12:09 a.m. EDT on the 1st of two KSC landing opportunities. At 10:28am EDT, APU Prestart was complete.

Mission Highlights:

STS-90 Flight Day 1 Highlights:
STS-90 Flight Day 2 Highlights:
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Last Updated Friday June 29 11:37:03 EDT 2001
Jim Dumoulin (