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Astronauts test entry systems for Friday landing BY WILLIAM HARWOOD STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION Posted: December 21, 2006 The Discovery astonauts tested the shuttle's re-entry systems today and packed up for a trip back to Earth Friday to close out a successful space station re-wiring mission. The only question today is where the seven astronauts will land. Because of an earlier decision to add a spacewalk to Discovery's mission, the shuttle only has enough supplies to remain in orbit until Saturday at the latest. To provide a safety cushion in case of unexpected problems with the spacecrat, NASA flight rules call for a return to Earth Friday, weather permitting, at one of the agency's three landing sites - the Kennedy Space Center in Florida, Edwards Air Force Base, Calif., or Northrup Strip at White Sands Space Harbor, N.M. With marginal to bad weather expected in Florida and California, NASA may be facing its first New Mexico shuttle landing since 1982. Because White Sands is NASA's lowest-priority landing site, equipment needed to prepare the shuttle for a ferry flight back to Florida is not readily available and Discovery's return to Kennedy would be delayed four to six weeks. NASA managers are hoping the forecast changes and that the weather will permit a landing in either Florida or California. The astronauts have landing opportunities at all three sites on four successive orbits Friday starting with a deorbit burn on orbit 203 at 2:49 p.m. for a landing on KSC runway 15 at 3:56 p.m. Edwards, Northrup and Kennedy are available on the next orbit, for landings around 5:30 p.m. EST, and two more opportunities, at Edwards and White Sands, are available the orbit after that around 7 p.m. EST. A final Edwards opportunity is available one orbit later, around 8:36 p.m. EST. Ground track charts available here. Entry data available here. Entry flight director Norm Knight, overseeing his first shuttle landing, plans to brief reporters later today on his re-entry strategy. Depending on the actual weather Friday, he will focus the entry team's efforts on the best opportunities for Florida and California. The forecast for the Kennedy Space Center calls for scattered clouds at 2,000 and 5,000 feet and a broken deck at 10,000 feet. But there is a chance for a broken deck at 5,000 feet and a chance for showers within 30 nautical miles, both flight rule violations. Winds will be gusting to 22 knots, but the crosswind component for a landing on runway 15 is just 2 knots or so. At Edwards, clouds are no problem but winds out of 290 degrees gusting up to 22 knots will result in a crosswind of about 20 knots for a landing on runway 22/04. The daylight crosswind limit is 15 knots and while that can be raised to 17 if turbulence is mild, forecasters are predicting moderate turbulence at Edwards. The outlook for Northrup Strip at White Sands calls for light winds and broken cloud decks at 15,000 and 20,000 feet. It is "go" for landing. Here are all the possible landing opportunities on Friday (in EST and subject to slight change): FRIDAY, DEC. 22 02:49 PM...12...18...02...Orbit 202 deorbit burn (TIG) for KSC landing 03:56 PM...12...19...09...202 KSC landing 04:19 PM...12...19...32...203 Edwards Air Force Base TIG 05:27 PM...12...20...40...EAFB landing 04:20 PM...12...19...33...203 Northrup Strip TIG 05:27 PM...12...20...40...Northrup landing 04:26 PM...12...19...39...203 KSC TIG 05:32 PM...12...20...45...KSC landing 05:54 PM...12...21...07...204 EAFB TIG 07:00 PM...12...22...13...EAFB landing 05:57 PM...12...21...10...204 Northrup TIG 07:02 PM...12...22...15...Northrup landing 07:32 PM...12...22...45...205 EAFB TIG 08:36 PM...12...23...49...EAFB landing Assuming the weather provides any chance at all, shuttle commander Mark Polansky, pilot William Oefelein and their crewmates will shoot for a landing in Florida on the first opportunity. That would require a "go" from mission control around 2:30 p.m. for a three-minute 17-second rocket firing at 2:49 p.m., lowering the shuttle's velocity by about 222 mph. After a half-hour free fall, the shuttle would enter the discernible atmosphere at an altitude of 400,000 feet - entry interface - at around 3:24 p.m. At that point, the orbiter would be 5,100 miles from runway 15 at the Kennedy Space Center with touchdown expected at 3:56:12 p.m. Here are preliminary numbers for a KSC entry on orbit 202 (in EST; minor changes expected): EST...........EVENT 10:49:00 AM...Begin deorbit timeline 11:04:00 AM...Radiator stow 11:14:00 AM...Mission specialists seat installation 11:20:00 AM...Computers set for deorbit prep 11:24:00 AM...Hydraulic system configuration 11:49:00 AM...Flash evaporator checkout 11:55:00 AM...Final payload deactivation 12:09:00 PM...Payload bay doors closed 12:19:00 PM...Mission control 'go' for OPS-3 entry software load 12:29:00 PM...OPS-3 transition 12:54:00 PM...Entry switchlist verification 01:04:00 PM...Deorbit parameters update 01:09:00 PM...Crew entry review 01:24:00 PM...Commander, pilot don entry suits 01:41:00 PM...Inertial measurement unit alignment 01:49:00 PM...CDR/PLT strap in; mission specialists suit don 02:06:00 PM...Shuttle steering check 02:09:00 PM...Hydraulic power system prestart 02:16:00 PM...Toilet deactivation 02:24:00 PM...Vent doors closed for entry 02:29:00 PM...Mission control 'go' for deorbit burn 02:35:00 PM...Mission specialists seat ingress 02:44:00 PM...Single APU start 02:49:05 PM...Deorbit ignition 02:52:22 PM...Deorbit burn complete (dV: 326 fps; dT: 3:17) 03:24:19 PM...Entry interface 03:29:19 PM...1st roll command to right 03:36:33 PM...1st left-to-right roll reversal 03:49:46 PM...Velocity less than mach 2.5 03:51:53 PM...Velocity less than mach 1 03:52:40 PM...253-degree left overhead turn to line up on runway 03:56:12 PM...Landing
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VIDEO:
WIDESCREEN VIEW FROM PLAYALINDA BEACH TRACKER 