NASA's new
Ares I-X rocket may be the world's largest booster currently in service or
about to fly, but it is no behemoth when compared to giant rockets of the past
and, perhaps, the future.
The Ares
I-X rocket is poised to launch on a suborbital
test flight on Oct. 27 and rolled out to
its launching pad earlier this week. It stands about 327 feet (100 meters)
high 14 stories taller than NASA's space shuttles and is equivalent in
height to its namesake Ares I. The Ares I booster is designed to launch NASA's Orion
spacecraft slated to replace the shuttle fleet.
"It gives
you a sense of the scale of what NASA does that our flight
test rocket is larger than any other rocket in the world," Ares I-X deputy
mission manager Jon Cowart told SPACE.com.
But the
Ares I-X and Ares I rockets are by no means the largest rockets ever built. In
fact, the Ares I-X is the third tallest rocket in history behind a pair of
giant boosters built to launch astronauts and cosmonauts to the moon. But
there's one future booster that could when built steal the "World's
Largest" title from the granddaddy rocket of them all, NASA's mighty Saturn V.
Here's a
look at some of the largest rockets in human history:
NASA's
Mighty Saturn V
The
reigning champion
of giant rockets is NASA's massive Saturn V, a three-stage booster used to
launch American astronauts to moon in the late 1960s and early 1970s.
Like the
Ares I-X and NASA shuttles, the towering Saturn V launched from the Kennedy
Space Center in Florida. It stood 363 feet (110 meters) high and remains the
most powerful rocket ever built, even though the last one flew in 1973.
The rocket
could launch payloads of up to 45 tons to the moon, or 120 tons into Earth orbit.
It weighed 6.5 million pounds (3 million kg) fully fueled at liftoff. The Ares
I-X weighs 1.8 million pounds (816,466 kg), slightly less than the full Ares I
rocket.
That last
Saturn V was a modified version that launched NASA's Skylab space station. Smaller
versions of the Saturn rocket were used to launch astronauts to Skylab, with
the last one a 224-foot (68-meter) Saturn 1B launching in 1975 to fly Apollo
astronauts to meet a Soviet Soyuz spacecraft during the Apollo-Soyuz joint
mission.
Ill-Fated
N-1
A close
second in the giant rocket race is the former Soviet
Union's N-1 rocket, an enormous booster designed to launch cosmonauts to
the moon during the Space Race with the United States.
The giant
rocket stood nearly 345 feet (104 meters) tall, had five distinct stages and
resembled a huge, tapering cone that was about 55 feet (17 meters) wide at the
base. During launch, it weighed 6.1 million pounds (2.7 million kg) and was
envisioned to launch payloads of up to 95 tons to space to send cosmonauts to
the moon, according to the Russian space history Web site Russianspaceweb.com
But the N-1
rocket never successfully reached space, despite four attempted launches. It
exploded during all four attempts between 1969 and 1972.
The former
Soviet Union did have other hefty rockets in its space launch inventory. The
enormous D-1E and D-1 variants of the Proton used for the 1968 lunar probe
missions and 1971 Salyut 1 space station launch. Neither came close to the
N-1's towering stature.
Today,
Russia still uses Proton rockets and smaller Soyuz boosters for to launch
satellites into orbit, though cosmonauts continue ride only Soyuz rockets into
orbit. The country is also developing a new family of Angara rockets.
Delta 4
Heavy
Before the
rollout of Ares I-X, the tallest rocket in service in the United States' inventory was
the Delta 4 Heavy, a heavy-lift version of the United Launch Alliance's Delta 4
booster.
Standing
235 feet (72 meters) tall, the Delta 4 Heavy made its launch debut in 2004, but
suffered a sensor glitch that prevented it from reaching its intended orbit.
The problem was promptly fixed. The rocket most recently launched a classified
satellite for the National Reconnaissance Office in January.
The Delta 4
Heavy is actually a group of three boosters, each called a Common Booster Core,
arranged in a line to give it a three-column look. At least two more Delta 4
Heavy missions are expected on the books for future classified satellite
launches, according to Spaceflight Now.
The rocket
is capable of launching payloads of up to 24 tons to low-Earth orbit and 11 tons toward
the geosynchronous orbits used by communications satellites, according to
Spaceflight Now. The Delta 4 Heavy is also touted to be able to launch 11-ton
payloads on trans-lunar injection orbit routes toward the moon and 8.8-ton payloads
on Mars-bound trajectories, Spaceflight Now has reported.
The
Mightier Ares V?
The claim
by Ares I and Ares I-X on world's tallest rocket may be fleeting if NASA's plan
to build a companion heavy-lift launcher bears fruit.
That giant
rocket the
enormous Ares V would reach a skyscraping height of 381 feet (116 meters)
that would surpass the Saturn V and set a new world record. The rocket is
designed to launch 207 tons (414,000 pounds) of cargo to low-Earth orbit and
78.5 tons (157,000 pounds) to the moon.
Designed
primarily to haul cargo, the Ares V booster is NASA's supply truck for the
post-shuttle era. The rocket consists of a giant core stage flanked by two
solid rocket boosters, each slightly larger than the first stage of Ares I.
A so-called
Earth Departure stage and Altair lunar lander would sit atop the core stage and
be launched into orbit to meet Orion spacecraft carrying moon-bound astronauts.
In place of the upper stage for moon missions, giant cargo modules or even
massive space telescopes could be packed away, according to a report by the
National Academies of Science. NASA hopes to have the Ares V rocket in operation for manned moon missions in the 2020s.
Comparison:
NASA's Space Shuttle Stack
NASA's
space shuttle fleet may seem puny compared to giant rockets of the past, but
its 28-year flight history makes it a good measuring stick when it comes to
booster match-ups. And, of course, it depends how you measure the shuttles.
On the ground,
each NASA space shuttle there are three orbiters remaining: Discovery, Atlantis and
Endeavour is about 122 feet (37 meters) long from nose to stern and stands 56
feet (17 meters) tall. They have a wingspan of about 78 feet (23 meters).
But in
launch position, the orbiter is perched on the side of its 15-story external
fuel tank and flanked by two solid rocket boosters. A shuttle on the launch pad
measures 184 feet (56 meters) tall from the tip of the external tank down to
the aft skirts of its twin solid rocket boosters.
The space
shuttle has a 60-foot (18 meter) long payload bay that is 15 feet (4.5 meters)
wide. Orbiters can haul large payloads into orbit, making the shuttle the only
spacecraft capable of launching massive segments of the International Space
Station, which occupied the bulk of the shuttle fleet's flight manifest for
more than a decade.
NASA has
launched 128 shuttle missions since the fleet's debut by Columbia in April
1981. There have been two failures: The shuttle Challenger and seven astronauts
were lost just after launch in January 1986 due to an O-ring seal leak in a
solid rocket booster that led to an explosion. The shuttle Columbia broke apart
during re-entry in February 2003 due wing heat shield damage. Seven astronauts
were killed.
After each accident, NASA stood down from shuttle flights to make safety improvements.
NASA
officials have said the new Ares I rocket, with its top-mounted capsule and
launch abort system, will be orders of magnitude safer than the current shuttle
design.
In addition
to Tuesday's Ares I-X launch test, launch abort system tests are scheduled to
begin in 2010, NASA officials have said.
SPACE.com
Staff Writer Clara Moskowitz contributed to this report. SPACE.com will provide
full coverage of NASA's Ares I-X test flight with Moskowitz in Cape Canaveral,
Fla., and Managing Editor Tariq Malik in New York. Click here for full mission coverage.
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