[X] My Assistant

[nprev]

Hey, all. So we're roughly 21 days (Earth, not Mars! ) from touchdown right now, and NASA has released a schedule of planned arrival coverage (link below). Their first look-ahead briefing is tomorrow. This thread will serve as a place to post resources for landing coverage, esp. given that some of our international members may be interested in local and/or language-specific options for same. If you happen know of any of those please post links here.

As per UMSF custom, there will be a dedicated landing thread opened for the big event when we get close. Remember to have your snacks & beverages of choice ready, and peanuts are optional but encouraged!

NASA Perseverance Arrival Coverage (Scheduled)

[Tom Tamlyn]

Today’s press briefing included an interesting exchange about the way the Terrain-Relative Navigation system works.

The excellent Irish reporter Leo Enright, a veteran of many Mars landing press conferences, repeated a question he'd asked at a prior briefing. He has been trying to find out how much "hover time is available to the skycrane," based on the available fuel, if the TRN system made the maximum possible alteration to the spacecraft's descent trajectory, which he had apparently been told would be the horizontal equivalent of "120 football fields."

Allen Chen responded that the notion of hover time was a misconception about the way the system works, because in fact the descent stage is always plummeting towards the surface and never hovers, except at the instant between the rover's touchdown and release of the cables. He said that the system can divert the landing point by as much as 700 meters, that the required maneuver would take place immediately after backshell separation, and that a maximum diversion would add no more than 3-4 seconds to the descent time and consume about 20 kg additional fuel.

The discussion takes place at ~52.30 in the video. https://www.youtube.com/watch?v=SO6__cLGkYw

[MahFL]

I saw that exchange too, I think what what is meant is the map is 120 football fields wide, but the TRN will land on the nearest safe spot, unless the entry is way off they won't be diverting 120 football fields or even 700 meters.