MSL’s initial trajectory was designed to miss Mars by a comfortable margin, to prevent the final launcher stage from contaminating the landing site. The first and largest maneuver for aiming MSL at Mars has just been completed successfully.

The maneuver used the eight thruster engines on the spacecraft, grouped into two sets of four. It began with a thrust lasting about 19 minutes, using just one thruster in each set and affecting velocity along the direction of the axis of rotation. Then, to affect velocity perpendicular to that line, each set of thrusters was fired for 5 seconds when the rotation put that set facing the proper direction. These 5-second bursts were repeated more than 200 times during a period of about two hours for a total of about 40 minutes.

Read more on jpl.nasa.gov

Curiosity carries a Radiation Assessment Detector (RAD) that will measure radiation levels on the Mars surface. But still underway to Mars, RAD is already commencing to measure radiation in space. High energy particles in space, emitted by the sun and galactic cosmic rays, are a liability to astronauts venturing outside of Earth’s magnetic field. Radiation levels have previously been measured at the surface of inter-planetary probes. RAD on the other hand, is placed deep in the interior of Curiosity to better represent an astronaut in a space ship.

The radiation recorded during the 8 month cruise phase can offer insights into the level of space radiation as well as into the influence of the vehicle’s structural elements. Secondary particles produced on impact of high energy space particles can cause more damage than the primary radiation itself.

The RAD instrument science return is detailed in a paper presented at the ’09 Lunar and Planetary Science Conference. Because of the Martian atmosphere’s poor shielding properties, RAD could demonstrate the necessity of including radiation impact in models of surface weathering and chemistry.

MSL has started its 8 month cruise journey to Mars. With the launch, NASA performed one of their most accurate injections ever into an inter-planetary orbit. MSL has been deliberately injected into a trajectory that misses Mars by 56 000 km. This way the upper stage of the launch vehicle that has joined MSL, but was not thoroughly decontaminated, will not spoil the Red Planet. The MSL trajectory will of course be adjusted to reach Mars, but the first course correction has been postponed by one month thanks to the very accurate injection.

After a demanding pre-launch schedule that focused on hardware reliability, engineers will now spend the time during the cruise phase to stress and improve Curiosity’s software. A mock-up rover on Earth will be subjected to simulations to reveal software limitations, and updated software will be transmitted to the real Curiosity in space. The final version of the landing software will be uploaded only in May 2012.

The Atlas V rocket launch was a complete success. The next Mars rover is on its way towards the Red Planet. A video of the launch is available at nasa.gov.