Journey to the Fourth Planet From the Sun
Curiosity Lands on Mars
A rise topped by two gray rocks near the center of the scene is informally named Twin Cairns Island. It is about 100 feet (30 meters) from Curiosity’s position. The two gray rocks, combined, are about 10 feet (3 meters) wide. (Photo courtesy of NASA/JPL-Caltech)
By Richard Park
The Mars rover Curiosity’s 352 million mile, eight-month trek came to fruition in August when it landed on the red planet’s surface. The Aerospace Corporation was closely involved in developing Curiosity, just as it had been with previous Mars rover missions. This was a nine-year effort, and Aerospace’s contributions were primarily on the front end, such as reviewing feasibility and risk, performing program assessments (e.g., cost and schedule), and making numerous technical contributions.
Aerospace played key roles in the following activities throughout the development of the Curiosity mission: performing structural and thermal analysis of avionics circuit boards, providing tribology consultation, and performing failure mode effects and criticality and fault tree analysis of the high torque actuators and controllers, as well as for the sample acquisition, processing, and handling instrument. Aerospace also reviewed the designs of the robotic arm, chemistry and camera instrument, propulsion subsystem, telecommunications subassembly, and rover battery thermal enclosure. The corporation provided environmental test support, requirements traceability and gap analysis, and a certification of flight readiness framework, as well as conducting test-as-you-fly and incompressible test compliance assessments.
Curiosity uses xray instrument data for proximity placement. (Photo courtesy of NASA/JPL-Caltech)
Curiosity’s journey through space ended in dramatic fashion during the entry, descent, and landing phase of the mission. As the spacecraft carrying Curiosity entered Mars’ atmosphere travelling at 13,200 miles per hour, it performed a series of guided entry maneuvers for the first four minutes. Once the spacecraft reached an altitude of seven miles and a velocity of 900 miles per hour, it deployed a 51-foot wide parachute. Two minutes later, when the spacecraft was only one mile above the ground and rushing toward it at 180 miles per hour, it fired its landing engines. After the engines decelerated the descent to 1.7 miles per hour, the spacecraft lowered Curiosity to the Mars surface using a sky crane bridle. When the spacecraft sensed touchdown for the rover, it severed the connecting cords and flew away.
Aerospace conducted the following tasks in support of this critical phase: organizing and leading the review of the sky crane concept, participating in the preliminary design review and critical design review of the descent brake, reviewing the designs of the bridle umbilical device, performing cruise stage separation analysis, powered descent, and rover separation assessments. Aerospace engineers and scientists also were involved in stage separation dynamics simulations, Monte Carlo separation analysis, and parachute mechanical loads analysis upon which the design requirements were based.
Curiosity has begun its two-year mission of investigating and assessing whether Mars has ever offered or still has conditions favorable to sustaining microbial life. Curiosity carried ten science instruments with a total mass that is 15 times as large as the science payloads of the previous Mars rovers.
Moving forward, Aerospace has worked with NASA and JPL to assess cost, schedule, and technical risks on four Mars mission concepts that are being considered for 2018 and 2020. These missions could include a Mars imaging and mineralogy science orbiter and three sample-caching rovers. At this point, the orbiter is projected to launch in 2018 on a Falcon 9 rocket. The first two rovers are projected to launch in 2020, also on a Falcon 9 rocket, and the third rover in 2020 on an Atlas V rocket. NASA has also asked Aerospace to assess another mission concept called the Mars small telecommunications orbiter. This orbiter would provide relay communications for Mars surface assets and possibly carry a small science instrument.