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Mars Rover Perseverance Discussion Thread


cubinator

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The new Perseverance rover will be launching from Earth in three days. This thread is meant for discussion about the rover and its adventures. This rover will arrive on Mars in February. It will record video of EDL, and audio for the first time directly. Its chassis looks similar to Curiosity, but its computing is more capable than Curiosity and it has greater autonomous driving and hazard detection capability, meaning the pathfinding need not be done so painstakingly by humans. It also carries the first aerodynamic flying vehicle to be deployed on Mars in the form of a small helicopter, and the ability to create caches of surface samples which can be picked up for return to Earth by a separate vehicle in the future. Oh, also it's mainly looking for stromatolites. :cool: 

 

Edited by cubinator
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Live presentation going on now! Tech on Perseverance that translates to human exploration. Landing hazard avoidance, weather forecasting, ground regolith study, oxygen manufacturing...

Edited by cubinator
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2 minutes ago, Nightside said:

How does the ‘copter control itself with just two blades?

It actually has four blades, as it has two counter-rotating rotors. Presumably it changes the pitch of each blade individually as they rotate to control the drone's attitude.

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12 minutes ago, Nightside said:

How does the ‘copter control itself with just two blades?

It handles rotation around vertical axis by adjusting rpm difference or pitch angle of rotors instead of tail rotor. Coaxial two rotor helicopters have been used in aviation too. Otherwise it has similar swashplate and pitch control as normal helicopter.

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Info graphics show that Centaur burn RCS almost continuously during coasting. I guess it is for keeping liquids where they should be. Why it can not use just short ullage burn just before ignition?

Edited by Hannu2
I separated answer and question not relates each other
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15 minutes ago, Hannu2 said:

Info graphics show that Centaur burn RCS almost continuously during coasting. I guess it is for keeping liquids where they should be. Why it can not use just short ullage burn just before ignition?

Noticed that too, it did an pretty long RCS burn before shutting off and did he settling RCS burn, guess it was an adjustment. Attitude on stream on injection burn was below listed Pe probably as it was estimated values, unlike in KSP you need to observe the spacecraft and calculate trajectory. This is also likely why they have some time from injection burn shutoff to separation. They want to verify trajectory before dropping it. 
 

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5 hours ago, Hannu2 said:

It handles rotation around vertical axis by adjusting rpm difference or pitch angle of rotors instead of tail rotor. Coaxial two rotor helicopters have been used in aviation too. Otherwise it has similar swashplate and pitch control as normal helicopter.

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Info graphics show that Centaur burn RCS almost continuously during coasting. I guess it is for keeping liquids where they should be. Why it can not use just short ullage burn just before ignition?

Just to clarify on the point, helicopters, unlike typical drones, can change the pitch on the rotor blades along the rotational path.  This allows differential lift across the area covered by the rotor to control pitch and roll.  NASA just mentioned they hope to fly Ingenuity within 50 to 90 days (or was it sols) of landing.

Congrats on NASA, JPL and ULA for a successful launch.  Can't wait to see version 2 of "7 Minutes of Terror" with GoPros all over the thing.

Edited by Soda Popinski
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On 7/30/2020 at 8:31 AM, Hannu2 said:

Info graphics show that Centaur burn RCS almost continuously during coasting. I guess it is for keeping liquids where they should be. Why it can not use just short ullage burn just before ignition?

The RCS props need to stay settled too. I do not believe that the Centaur's hydrazine monoprop thrusters have the same surface-tension-based propellant settling reservoirs that were used by the Shuttle OMS engines/thrusters or the Draco thrusters. Soyuz doesn't use surface tension; I believe it uses a metal diaphragm. 

EDIT: I'm wrong; the Centaur uses bladder tanks for its hydrazine RCS. Oops. I guess maybe the constant RCS burn is to counteract drag in the low parking orbit? Also, I know that keeping the main props continuously settled reduces boiloff, which is particularly important for hydrolox.

Edited by sevenperforce
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 I would have loved to have seen a true microscope sent to Mars. After more than half a dozen landers there still has not been sent a true optical microscope sent. The best resolving power has been at no better than that of a geologists hand lens.

 This would have importance for the search for possible life, but also for geological samples.

 

  Bob Clark 

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  • 6 months later...

This hasn't been posted here yet so :

Livestream starts Feb 18 2:15 PM EST (Feb 18 11:15 AM PST, Feb 18 19:15 UTC, Feb 19 02:15 UTC+7).

Touchdown approx. Feb 18 3:15 PM EST (Feb 18 12:15 PM PST, Feb 18 20:15 UTC, Feb 19 03:15 UTC+7). Confirmation would only come after the light delay ofc.

Edited by YNM
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