Rollout of the towering Space Launch System (SLS) rocket
with its Orion crew capsule perched on top marks a key milestone in US plans
for renewed lunar exploration after years of setbacks, and the public's first
glimpse of a space vehicle more than a decade in development.
The process of moving the 5.75-million-ton, 32-story-tall
SLS-Orion spacecraft out of its Vehicle Assembly Building at NASA's Kennedy
Space Center in Cape Canaveral was scheduled to begin at 5pm EDT (2:30am IST on
Friday), weather permitting.
The megarocket — standing taller than the Statue of Liberty
— will be slowly trundled to Launch Pad 39B on a giant crawler-transporter, a
4-mile (6.5-km) journey expected to take about 11 hours. The spectacle will be
carried live on NASA Television and the space agency's website.
Forecasts on Wednesday called for favourable conditions
along Florida's Atlantic coast.
The rollout, paving the way for NASA's uncrewed Artemis I
mission around the moon and back, was delayed last month by a series of
technical hurdles the space agency said it has since resolved as teams readied
the rocket for the launch pad.
"We are in very good shape and ready to proceed with
this roll on Thursday," Charlie Blackwell-Thompson, Artemis launch
director, said earlier in the week as she briefed reporters on NASA's progress.
Once secured at the pad, the SLS-Orion ship is to be
prepared for a critical pre-flight test called a "wet dress
rehearsal," which will begin on April 3 and take about two days to
complete.
Engineers plan to fully load the SLS core fuel tanks with
super-cooled liquid hydrogen and liquid oxygen propellant and conduct a
simulated launch countdown — stopping seconds before the rocket's four R-25
engines would ignite — in a top-to-bottom evaluation of the entire system.
From Apollo to Artemis
The outcome will determine when NASA will attempt its first
launch of the rocket and capsule combination, a mission designated Artemis I.
The SLS-Orion constitutes the backbone of the Artemis program, aimed at returning
astronauts to the moon and establishing a long-term lunar colony as a precursor
to eventual human exploration of Mars.
The US Apollo program sent six manned missions to the moon
from 1969 to 1972, the only crewed spaceflights yet to reach the lunar surface.
Artemis, named for the twin sister of Apollo in Greek mythology, seeks to land
the first woman and the first person of colour on the moon, among others.
But NASA has several steps to take before it gets there,
starting with a successful Artemis I flight, planned as an uncrewed journey
40,000 miles (64,374 km) beyond the moon and back. NASA has said it was
reviewing potential launch windows in April and May, but the timeline could
slip depending on results of the dress rehearsal.
Eight or nine days after those tests are completed and the
propellant is drained from the rocket, the ship will be rolled back to the
assembly building to await the setting of a launch date.
NASA announced in November that it would aim to achieve its
first human lunar landing of Artemis as early as 2025, preceded at some
unspecified date by a crewed Artemis flight around the moon and back.
Both of those missions, and others to follow, will be flown
to space by the SLS, which surpasses the Apollo-era Saturn V as the world's
largest, most powerful launch vehicle, and the first exploration-class rocket
built by NASA for human spaceflight since Saturn V. © Reuters