MSL 'Curiosity': SUCCESS!!

[VJ]

Perhaps a strange question, but what are the benefits of the "flying crane" to land the rover? It seems to me an overly complicated contraption. Is it only because it is much more compact?

[Dr Mordrid]

The advantage is its ability to land such a large rover - this thing's the size of a Mini Cooper - using the minimum mass.

An air bag like used previously would be crushed, and a landable platform with ramps would be much larger, heavier and require a much larger payload fairing than the 5.4 meter fairing they used - one not in the inventory. All this mass is so heavy either an untested block of Atlas V using 2 Centaurs and 5 SRB's or a much more expensive Delta IV Heavy ($350 million itself without the custom fairing) would be needed. That or wait for Falcon Heavy or SLS - and the latter is 4-5 years further out than FH.

By parachuting a composite half-clamshell and a skeletal hover stage (no landing gear of its own or strengthening to use them) to a lower altitude with a lightweight alloy crane it solved a lot of issues.

As far as the automated hover stage itself goes, this is a well developed tech. McDonnell Douglas used a basic form in the early 1990's for DC-X, and several NewSpace companies have developed it to an art; Masten Space, Armadillo Aerospace and others. SpaceX and Blue Origin will use it in their vertically-landing fly-back boosters, and crew Dragon's DragonRider landing system will also use it.

(see the SpaceX VTVL thread)

[VJ]

So mainly weight and size related... Thanks!

[Dr Mordrid]

There will be a midcourse correction - a minor one

http://www.jpl.nasa.gov/m/news/index.cfm?release=2012-004

Trajectory Maneuver Slated for Jan. 11

Mars Science Laboratory Mission Status Report

PASADENA, Calif. -- An engine firing on Jan. 11 will be the biggest maneuver that NASA's Mars Science Laboratory spacecraft will perform on its flight between Earth and Mars.

The action will use a choreographed sequence of firings of eight thruster engines during a period of about 175 minutes beginning at 3 p.m. PST (6 p.m. EST or 2300 Universal Time). It will redirect the spacecraft more precisely toward Mars to land at Gale Crater. The trajectory resulting from the mission's Nov. 26, 2011, launch intentionally misses Mars to prevent the upper stage of the launch vehicle from hitting the planet. That upper stage was not cleaned the way the spacecraft itself was to protect Mars from Earth's microbes.

The maneuver is designed to impart a velocity change of about 12.3 miles per hour (5.5 meters per second).

"We are well into cruise operations, with a well-behaved spacecraft safely on its way to Mars," said Mars Science Laboratory Cruise Mission Manager Arthur Amador, of NASA's Jet Propulsion Laboratory, Pasadena, Calif. "After this trajectory correction maneuver, we expect to be very close to where we ultimately need to be for our entry point at the top of the Martian atmosphere."

The mission's schedule before arrival at Mars on Aug. 5 in PDT (Aug. 6 in Universal Time and EDT) includes opportunities for five more flight path correction maneuvers, as needed, for fine tuning.

The Jan. 11 maneuver has been planned to use the spacecraft's inertial measurement unit to measure the spacecraft's orientation and acceleration during the maneuver. A calibration maneuver using the gyroscope-containing inertial measurement unit was completed successfully on Dec. 21. The inertial measurement unit is used as an alternative to the spacecraft's onboard celestial navigation system due to an earlier computer reset.
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[Dr Mordrid]

Unbelievable!!!!

Looks like not only a bulls-eye landing, but the center of the center of the targets bulls eye. The landing speed was just 3.68 cm (1.44 inches) per second, and it landed less than 1.5 meters (4 feet) from the mission AP (aiming point.) DAMN!!!! They stuck it!!!

Color images from the NavCams could be transmitted early, perhaps later today, and ESA's Mars Express is confirming the RTG (nuclear power cell) is alive and recharging the rovers batteries.

[cjolley]