STS-98 Status Report #21 17 Feb 2001 5:00 PM CST

Atlantis’
astronauts made sure today that all of the systems they will use in
Sunday’s planned landing are in good working order, and finished
packing up for the ride home.

Commander Ken Cockrell
and Pilot Mark Polansky tested the manifold valves of their reaction
control system jets, but didn’t perform the usual “hot firing”
of the jets that will be used to guide the shuttle’s descent into
the atmosphere, since the jets were used extensively during the mission.
They also checked out Atlantis’ three hydraulic power units and
the aerodynamic control surfaces they drive.

Before lunch, Cockrell
and Polansky were joined by Mission Specialists Robert Curbeam, Tom
Jones and Marsha Ivins for a review of the deorbit and entry procedures
they’ll use. After lunch, the entire crew pitched in to stow their
supplies and equipment for landing, and took turns exercising.

There are two landing
opportunities available Sunday for Atlantis in Florida. The first begins
with a deorbit burn on Orbit 169 at 10:47 a.m. and culminates in a landing
at 11:53 a.m. Central time on Runway 33 at Kennedy Space Center. A backup
opportunity one orbit later starts with a deorbit burn at 12:22 p.m.,
resulting in a 1:28 p.m. Central time landing. The weather forecast
Sunday calls for generally favorable conditions in Florida, with the
possibility of brisk winds near the three-mile-long landing strip.

Meanwhile, on the
the International Space Station, Expedition One Commander Bill Shepherd,
Pilot Yuri Gidzenko and Flight Engineer Sergei Krikalev are enjoying
a weekend off before forging ahead with activation of the newly arrived
Destiny laboratory’s systems. Next week, they’ll also get
ready to undock and move their Soyuz vehicle from the Zvezda module’s
aft docking port to the Zarya module’s nadir port.

With the departure
of Atlantis, Shepherd, Gidzenko and Krikalev returned to their normal
operational schedule, going to sleep at 3:30 p.m. and waking up at midnight
central time. On the shuttle, the five astronauts will begin their sleep
period tonight 30 minutes earlier than on previous days, at 7:43 p.m.
Central time, and awaken at 3:43 a.m. to begin suiting up for landing.

Atlantis and the
International Space Station continue to revolve around the Earth in
great shape, with all systems functioning normally. The shuttle is leading
the station by about 215 statute miles, with the gap widening by about
15 miles every orbit.

The Johnson Space
Center newsroom will close at 9 p.m. and reopen at 4 a.m. Sunday. The
next mission status report will be issued at 5 a.m. Central time Sunday.