Sensors collected crucial data on landings with arrival of Perseverance

(1 April 2021 – JPL) NASA’s Perseverance rover efficiently landed Feb. 18, 2021, starting its robotic exploration of the Purple Planet.

MEDLI2 was one of many essential applied sciences on the rover’s protecting aeroshell that helped doc the entry, descent, and touchdown (EDL) of the spacecraft. All the MEDLI2 information was saved on Perseverance for transmission to Earth after a profitable touchdown.

MEDLI2’s position was to gather essential information in regards to the harsh atmosphere throughout Perseverance’s entry by the planet’s environment. It included three kinds of sensors – thermocouples, warmth flux sensors, and stress transducers – that measured excessive warmth and stress throughout entry. It additionally contained electronics and {hardware} for recording the thermal and stress masses skilled throughout entry and thru the parachute deployment.

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The Mars 2020 spacecraft’s warmth protect falls away because the aeroshell descends to Mars on Feb. 18, 2021. The orange cabling seen on the protect is a part of a set of sensors and electronics referred to as MEDLI2, which collects information in the course of the descent that can assist engineers land future spacecraft on Mars. (courtesy: NASA/JPL-Caltech)

MEDLI2 used its measurements to find out the heating and atmospheric forces that occurred on the warmth protect and again shell. Collectively, these two parts make up the aeroshell, which housed and guarded the Perseverance rover in the course of the cruise to Mars and EDL.

MEDLI2 was powered on 5 hours earlier than the “7 Minutes of Terror,” or remaining 7-minute descent to Mars. This supplied time for MEDLI2’s electronics to stabilize temperature and measure the preliminary situations previous to entry. The crew was relieved to obtain the indication that MEDLI2 was efficiently activated. The crew continued to watch the incoming information all through this five-hour coast part previous to entry.

Nearly all of the MEDLI2 sensors and the first electronics had been mounted on the Mars 2020 warmth protect. About 10 seconds after the supersonic parachute deployed, MEDLI2 was powered down for the final time because it had accomplished its job. Since it’s essential for the warmth protect to be separated to permit the Perseverance rover to be extracted from the entry car, it was required that MEDLI2 be turned off just a few seconds earlier than the separation to forestall any electrical energy points. The harness connecting the warmth protect and again shell was then severed by the firing of a pyro-cutter, and the warmth protect was .

“We didn’t discover any points with the separation,” stated Henry Wright, MEDLI2 mission supervisor at NASA’s Langley Analysis Heart in Hampton, Virginia. “The warmth protect cleanly separated from the Mars 2020 entry car. The MEDLI2 {hardware} was clearly seen on the warmth protect because it fell towards the floor of Mars. Job effectively executed!”

Perseverance additionally returned “essential occasion information” in actual time in the course of the EDL. It included a subset of the MEDLI2 information which allowed observations into what the entry car was experiencing because the entry was occurring. Three days after Perseverance’s profitable touchdown, the remaining MEDLI2 information was transmitted again to Earth, and the following part of the mission started: information evaluation and efficiency reconstruction.

“The returned information is fascinating. It’s like having a chicken’s eye view of what’s occurring to the aeroshell because it flies by Martian skies. The MEDLI2 sensor alerts are so clear we might instantly select fascinating phenomenon and essential occasions” stated Todd White, MEDLI2 principal investigator at NASA’s Ames Analysis Heart in California’s Silicon Valley.

Knowledge from MEDLI2 additionally supplies measurements that can be used to find out the properties of the environment the Mars 2020 entry car flew by. MEDLI2 supplies important EDL remark information to know how a lot margin remained on the Perseverance entry together with information that can be used to enhance prediction fashions and instruments for future missions.

Taking a Deeper Look Into the Knowledge

Warmth protect insulation temperatures had been recorded all through the whole entry part and had been in line with the entry predictions. The height measured temperature within the warmth protect in the course of the entry was 1,830 levels Fahrenheit, or 1,000 levels Celsius. That correlates to an estimated peak warmth protect outer temperature of about 2,550 levels Fahrenheit, or 1,400 levels Celsius.

MEDLI2 additionally used its embedded thermocouples to find out how a lot of the warmth protect protecting insulation might have burned away or ablated. All the thermocouples survived the entry heating pulse, indicating the warmth protect ablation was very low. This remark might be used to reevaluate the quantity of insulation that’s wanted on a warmth protect to probably scale back the entry car mass.

Floor pressures had been additionally measured all through the identical part with a peak floor stress of the warmth protect matching the crew’s entry predictions. MEDLI2 picked totally different sensors to concentrate on precisely capturing totally different flight regimes. One sensor lined the whole vary of the utmost floor pressures. The remaining six warmth protect stress measurements had a variety to extra precisely seize the situations in the course of the supersonic flight regime (from about 5 occasions the velocity of sound on Mars by the deployment of the supersonic parachute). These sensors, mixed with onboard inertial measurements, permits extra perception into how the entry car performs when the impacts of atmospheric density variations and winds are extra pronounced. The MEDLI2 stress information can be used to enhance the modeling strategy for future EDL missions.

MEDLI2 included sensors on the again shell of the Mars 2020 entry car, an space that till now has had restricted observations. Floor stress, insulation temperature, and direct floor heating measurements comprised the again shell sensor suite. Data of the floor stress on the again of the entry car contributes to a discount within the dimension of the touchdown footprint. Again shell insulation temperature information was throughout the preliminary predictions, which can be utilized to cut back the modeling uncertainty. As with the warmth protect insulation, understanding the again shell insulation temperature efficiency might result in a discount within the again shell insulation mass. Direct floor heating measurements of the again shell additionally contribute to lowering the uncertainty within the predictive fashions.

MEDLI2 information additionally included a variety of “housekeeping” measurements. These included a variety of compensating temperature measurements of essential science sensors. A lot of this housekeeping information can be of eager curiosity to the Mars 2020 crew to help in their very own EDL reconstruction efforts. A part of the housekeeping measurements included sensors inner to the MEDLI2 assist electronics (voltages, inner temperatures, MEDLI2 heartbeat/clock, and so on.).

The MEDLI2 crew will proceed to the info for the following six months, refining NASA’s understanding of the Mars environment, the intense situations of entry, and the way effectively the Mars 2020 aeroshell protected the rover. These classes can be instantly helpful for the following Mars missions, and even missions headed for Titan.

Langley led the MEDLI2 instrument improvement and mission administration. NASA’s Ames Analysis Heart in California’s Silicon Valley and NASA’s Jet Propulsion Laboratory in Southern California contributed to MEDLI2. NASA’s Recreation Altering Growth program throughout the Area Expertise Mission Directorate funded the expertise improvement.

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