Spirit is launched: Rover's seven-month journey to Mars begins
June 12, 2003
By Blaine P. Friedlander Jr.
The planets were aligned, two days of high winds and thunderstorm
threats abated, and on June 10 a Delta II rocket carrying a roving
vehicle the size of a golf cart left behind a plume of fire and vapor
for NASA's latest quest to Mars.
After bad weather postponed two launch attempts, one on Sunday and the
other on Monday, the rocket carrying the first of two Mars Exploration
Rovers, newly named Spirit, roared off from Cape Canaveral Air Force
Station, Fla. The mission will take Spirit and its Athena suite of
scientific instruments, developed by a team led by Cornell astronomer
Steven Squyres, to a scheduled Jan. 4 touchdown on the planet's surface.
"It was a picture-perfect launch. Delta gave us a perfect ride," said an
elated Squyres. "It looks like we've got a healthy spacecraft going to
Mars," he said after studying the telemetry, the indicators describing
the spacecraft's functions.
But there was no time for him to celebrate. "We have to get ready for
the next launch in two weeks," he said. The second rover, the newly
named Opportunity, carrying an identical Athena package, is scheduled
for launch on June 25.
More than an hour before Sunday's scheduled launch, NASA and military
officials decided to postpone the mission as towering thunderstorm
clouds grew quickly in the sultry June afternoon air of central coastal
Florida.
Joel Tumbiolo, a meteorologist with the U.S. Air Force's 45th Weather
Squadron and the mission's launch weather officer, had predicted poor
climate conditions from Sunday through Tuesday. "Many people wish I
would just go away," he told a press briefing June 7. "Every afternoon
for the past few days, storms have been building in the area south of
Cape Canaveral and then moving in our direction."
The weather met Tumbiolo's prediction. Following the Monday scrub, NASA
and Air Force weather forecasters got what they hoped for on Tuesday, as
dry conditions settled over the Cape. The forecasters had fretted about
cumulus clouds, developing thunderstorms and anvil clouds growing within
the vicinity of the launch pad and the Delta rocket flight path.
Despite the delay, the scientists and the engineers took the wait in
stride. "Well, we scrubbed today. That happens a lot in the rocket
business," said Squyres, writing June 9 in the latest entry in his
online personal journal on the Athena Web site at
http://www.athena.cornell.edu/news/.
"Scrubs happen for all kinds of reasons. Usually it's weather, and
that's what got us today."
Squyres explained why NASA simply cannot launch a rocket at will:
"Because the Earth is always spinning, you need to wait until it's at
just the right point in its spin to launch. Otherwise, you would be
headed off in the wrong direction."
Because scientists want the mission to succeed, "You might think it
would be frustrating when something like this happens, but it really
isn't," said Squyres. "We've waited so long to fly these things that
another day doesn't seem like much. And with $400 million worth of
hardware out on the pad, we really don't want to take chances. So we'll
try again tomorrow."
The spacecraft is taking the 384-pound rover on a seven-month, 311
million-mile ride to Mars, with arrival scheduled for Jan. 4. That is a
relatively short time considering that a normal journey to Mars can take
10 to 12 months. But celestial mechanics is working in NASA's favor, as
this summer Mars will be at its closest position to Earth in recorded
history.
As the spacecraft enters the top layer of the Martian atmosphere, racing
at 12,000 miles an hour, a capsule sheath will protect the rover, with a
heat shield reminiscent of NASA's Mercury and Gemini capsules of the
1960s. Despite the planet's thin atmosphere, engineers at NASA and the
Jet Propulsion Laboratory (JPL), the mission's manager, believe that the
temperature on the heat shield could reach 2,637 degrees Fahrenheit.
About five miles above the Martian surface, a parachute will deploy and
slow the craft to about 960 miles an hour. Within 20 seconds the craft
will jettison the heat shield, exposing the landing craft, and radar
will start calculating the distance to the ground.
Eight seconds before touchdown, gas generators will inflate the
airbag-landing system, making the craft look like a soccer ball on
steroids. From there, it will bounce onto the Martian surface and travel
as far as two kilometers before stopping. The landing site is Gusev
Crater, "which is like landing somewhere between the beach and Orlando,"
said Firouz Naderi, Mars exploration program manager at JPL.
From there, the craft will orient itself and open like the petals of a
flower on a warm, spring day. Then it will begin its long, Martian
surface trek, traveling up to 44 yards a day, taking panoramic
photographs, microscopic images of the surface, rock samples and
spectrometry readings.
In a prelaunch press conference at the Cape on June 6, Squyres alluded
to the history of the Athena suite of scientific instruments. This
journey to Mars had been "a decade in the making, but a three-year
sprint to the finish," he said.
Referring to the rovers' panoramic cameras that will provide pristine
views of the surface in a 360-degree panorama, he noted to the media,
"It's Mars like you've never seen it before."
Squyres said his science team is expected to meet daily during the two
rovers' three-month deployment on the planet's surface in order to reach
a consensus on what to explore. The meeting time also will change daily
by 39 minutes to accommodate the rovers' schedule on Mars, where days,
called sols, are 39 minutes longer than those on Earth. Paraphrasing
Neil Armstrong, Squyres said: "This is not a small step, this is a
giant leap."
