An Inside Look To The Technology of the Mars Rover "Perseverance"
The largest Mars payload ever is Perseverance, which is roughly the size of a vehicle and weighs a ton (on Earth). The rover will look for evidence of prehistoric life after landing and collect samples that will eventually be brought back to Earth. While the hardware will be identical to that of the 2012 Mars Science Laboratory (MSL) mission, which successfully landed the Curiosity rover, there will be some modifications, such as increased landing precision for the rover. The journey of Curiosity revealed a plethora of knowledge about the environment that Mars would encounter and the technology that would be required for survival.
There isn't much atmosphere for approaching spacecraft to use to aerodynamically slow down due to Mars' harsh and distant environment and atmosphere, which is around 100 times thinner than Earth's. It takes a clever combination of aerodynamics, parachutes, retropropulsion (using engine thrust to decelerate for landing), and frequently a sizable airbag to survive entrance to Mars. Additionally, since real-time weather forecasts for Mars are not available, it is unknown exactly what conditions a probe will encounter upon entry. Landing accuracy has declined in earlier missions due in part to unpredictable meteorological conditions, particularly dust storms.
The "seven minutes of fear" are how NASA engineers refer to the entry, descent, and landing (EDL) phase of Mars entry missions. There are numerous ways entry may go wrong in just seven minutes. A 4.5-meter-diameter heat shield was installed on the 2012 MSL mission to keep the probe safe as it descended into Mars' atmosphere. It accelerated to about 5,900 m/s as it hit the Martian atmosphere. It is more than five times as fast as sound, making it hypersonic. It will be comparable to this one. To prevent hot flow from harming the rover stored inside, it will mainly rely on its thermal protection system, which includes a front heat shield and backshell heat shield.
Mars's atmosphere won't be able to move out of the way of the spaceship quickly enough at hypersonic speeds. Consequently, a powerful shock wave will develop off the front. Gas in front of the vehicle will in this scenario be compressed quickly, resulting in a significant increase in pressure and temperature between the shock wave and the heat shield. During entry, the hot post-shock flow warms up the heat shield's surface, but the heat shield shields the inside structure from this heat. The MSL 2012 and this new mission's spacecraft are more likely to overheat during the entry phase due to the missions' considerably heavier payloads. MSL, however, successfully got around this problem, in large part because of a specifically created heat shield that was the first ever to use NASA's Phenolic Impregnated Carbon Ablator (PICA) material. Chopped carbon fibers incorporated in a synthetic resin make up this substance. It is incredibly light, incredibly heat-absorbing, and a good insulator.
Prior to the 2012 MSL mission, all previous entry had been unguided, which meant that a flight computer did not control them in real-time. Instead, the spacecraft were planned to land wherever the Martian winds carried them after striking Mars' "entry interface" (125 km above ground). This led to a great deal of landing uncertainty. The thrusters controlling the spacecraft's angle during MSL 2012's Mars entry are depicted in this artist's impression. The similar approach will be used by the upcoming Mars expedition. The landing ellipse is the area where landing is uncertain. The landing ellipse for NASA's Viking Mars missions in the 1970s was roughly 280x100km. However, MSL and Mars 2020 were both designed to perform better than earlier attempts.
The first guided Mars entry was made by the MSL mission. The vehicle was controlled in real time by an improved version of the Apollo guidance computer to assure a precise landing. As a result, MSL's anticipated landing ellipse was decreased to 20x6.5km, and it ultimately landed just 2km from its objective.
