Thread by @WeAreSpaceScout

Ready for the #CountdownToMars? #Perseverance is set to begin its entry, descent, and Martian landing in just under 5 hours from now, at 12:55 p.m. PST (20:55 UTC). We'll be covering it here on Twitter.

What you need to know for today's #Mars landing:
spacescout.info/2021/02/persev…

In order for today's landing to work successfully, the #Mars2020 mission needs to bleed off over 5,000 m/s of velocity within just four minutes, and conduct a rocket-powered crane descent. Here's today's descent timeline - also included in the article. #CountdownToMars

At 11:15 a.m. Pacific, NASA will start coverage of the landing on NASA TV, available globally. We'll be tweeting clips during our coverage, too.

Set a reminder for the launch stream:

Perseverance now operating on its own as it cruises on its way to Mars. #CountdownToMars #Mars2020

Now just one hour to entry interface. #CountdownToMars #Mars2020

LANDING RUNDOWN: We're currently 40 minutes from entry interface (identified as E). At E- 10 minutes, the cruise stage will separate from Perseverance, leaving only the re-entry shell and the rover. Entry interface will be at 12:48 pm. PST at 5,400m/s. #CountdownToMars #Mars2020

At E+1:20, Perseverance will hit its peak heating, quickly followed by peak deceleration at +1:30. After finishing the entry phase, Perseverance will deploy its supersonic parachute at +4:00, at a velocity of 420 m/s.

#CountdownToMars #Mars2020

At E+4:20, the heatshield will separate at a velocity of 160 m/s. During the descent portion, Perseverance will enter radar lock at +4:50, and terrain-relative navigation at +5:30.

Landing begins when Perseverance separates its backshell, at +5:50. #CountdownToMars #Mars2020

Following separation of the backshell, Perseverance will fly under skycrane power, slowing down from 89m/s to just 0.75m/s within a minute. Finally, at E+6:30, the skycrane will slowly lower Perseverance, with touchdown at +6:50, 12:55 p.m. PST. #CountdownToMars #Mars2020

Landing confirmation is expected within 16 seconds of touchdown (relative to Earth's perspective) from MRO which will be flying overhead. Secondary communication attempts can happen at L+10 and L+15 minutes, as well as a MAVEN pass in 10 hours. #CountdownToMars #Mars2020

"I look forward to seeing you all on the other side."

"Welcome to the EDL family."

"Godspeed, Perseverance."

#Mars2020 #CountdownToMars

30 minutes to touchdown, relative to Earth. #CountdownToMars #Mars2020

15 minutes to entry, 22 to landing. The cruise stage will separate in just five minutes, with the main transmitter being shutdown. The only signal that Perseverance will have until entry interface will be a "heartbeat" signal with no complex data. #CountdownToMars #Mars2020

Perseverance's pyrotechnics bus to decouple the cruise stage is enabled. Cruise stage now in power-down. #CountdownToMars #Mars2020

First pyrotechnics for coolant have been fired.

Cruise stage separation in 2 minutes, 10 seconds. #CountdownToMars #Mars2020

One minute to cruise stage separation. 11 minutes to EDL. Spacecraft now broadcasting heartbeat tones. #CountdownToMars #Mars2020

CRUISE STAGE SEPARATED. Complex data communications have been ceased with Perseverance. Entry interface in 10 minutes. #CountdownToMars #Mars2020

Perseverance's communications are currently cut off as the cruise stage is shadowing the line of sight for the vehicle. #CountdownToMars #Mars2020

Communications restored. The entry thrusters are pulsing and landing software has activated. Perseverance is attempting to slow down its spin from the cruise stage from 2 rpm to 0 for EDL. E- 7 minutes, 20 seconds. #CountdownToMars #Mars2020

Mars Reconnaissance Orbiter has acquired carrier lock. #CountdownToMars #Mars2020

"And now, we wait."

Landing, in real time and not adjusted for Earth delay, should have been one minute ago. #CountdownToMars #Mars2020

90 seconds to entry. MRO is now attempting to send telemetry to NASA. Velocity now 5,400 meters per second. #CountdownToMars #Mars2020

30 seconds to entry interface. Communications loss is expected in 2 minutes. #CountdownToMars #Mars2020

MRO in recieve mode. #CountdownToMars #Mars2020

ENTRY INTERFACE INITIATED. #CountdownToMars #Mars2020

ENTRY INDICATED. Perseverance is now slightly slowing down, traveling Mach 28.35 at 5.36 km/s. Altitude 67 km. #CountdownToMars #Mars2020

MRO PLASMA BLACKOUT. #CountdownToMars #Mars2020

MAXIMUM DECCELERATION. 10 G. #CountdownToMars #Mars2020

MRO REGAINED LOCK. Communications restored. #CountdownToMars #Mars2020

Perseverance continuing to do bank reversals in the atmosphere, aiming towards its landing target. 4 minutes to landing. #CountdownToMars #Mars2020

Perseverance now at 20% of its original velocity, 1 km/s, at 16 kilometers of altitude. #CountdownToMars #Mars2020

Perseverance has entered heading alignment and is flying directly to its target. #CountdownToMars #Mars2020

Perseverance now traveling Mach 2.5, 530 m/s, at 15 km. #CountdownToMars #Mars2020

CHUTE DEPLOY. #CountdownToMars #Mars2020

PERSEVERANCE IS TRANSONIC. MACH 0.85, 196 m/s, and heatshield separation! #CountdownToMars #Mars2020

RADAR LOCK. 1 minute, 30 seconds to landing. #CountdownToMars #Mars2020

Correction, 1 minute, 30 seconds *NOW*.

Terrain-relative navigation engaged. 83 m/s at 2.6 km. #CountdownToMars #Mars2020

BACKSHELL SEP. SKYCRANE DEPLOY. #CountdownToMars #Mars2020

30 M/S. ENGINES ARE FIRING. CRAFT IS LEVEL. #CountdownToMars #Mars2020

CONSTANT VELOCITY. Perseverance is successfully controlling its maneuvers and throttling down. #CountdownToMars #Mars2020

PERSEVERANCE HAS LANDED ON MARS! #CountdownToMars #Mars2020

"Touchdown confirmed. We're gonna wait for the images." #CountdownToMars #Mars2020

Completion of EDL. MRO is still seeing a strong signal from the lander. #CountdownToMars #Mars2020

IMAGES RECIEVED FROM PERSEVERANCE! #CountdownToMars #Mars2020

CLEAN IMAGES FROM PERSEVERANCE! #CountdownToMars #Mars2020

"Take that, Jezero!" #CountdownToMars #Mars2020

MORE PHOTOS: #CountdownToMars #Mars2020

"We have seen the transition to surface, EDL is done!"

"Congratulations, Perseverance team!"

#CountdownToMars #Mars2020

"All stations! Congratulations, but believe it or not, we have a job to do now!"

The cruise stage burned up with 55.91 kg remaining, and the skycrane had 96 kg of propellant out of 401 remaining. #CountdownToMars #Perseverance

We'll be taking a break in our coverage for a few minutes. Watch the clean feed from JPL here: