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#### Marc_G

##### Well-Known Member
So much amazing stuff worked so far. I wonder what the failure was with the microphone put in to record descent? They didn't get into details during the briefing (but, I had to bail early). It sounds like the camera is now operating and they played wind sounds (couldn't hear them on my computer audio with a conference call in background).

Go NASA!

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#### Marc_G

##### Well-Known Member
Great day to be an earthling, a human, and an American!

#### Cape Byron

##### The BAR formerly known as Skippy-2
TRF Supporter
Great day to be an earthling, a human, and an American!
I'll have to be Meatloaf on that one...

Two out of three ain't bad...

#### Huxter

##### Well-Known Member
TRF Supporter
Mr O caught Curiosity landing as well.
Wonder if we'll get video from Mr O for Perserverence landing? Curiosity:

#### OverTheTop

##### Well-Known Member
TRF Supporter
Dare Mighty Things

"Internet sleuths claim to have decoded a hidden message displayed on the parachute that helped Nasa’s Perseverance Rover land safely on Mars last week. They claim that the phrase “Dare mighty things” – used as a motto by Nasa’s Jet Propulsion Laboratory – was encoded on the parachute using a pattern representing letters as binary computer code.

Reddit users and social media posters on Twitter noticed that the red-and-white pattern on the parachute looked deliberate, and arrived at the result by using the red to represent the figure one, and the white to represent zero.

Each of the concentric rings in the parachute’s pattern represents one of the words. The zeroes and ones need to be split up into chunks of 10 characters, and from that, adding 64 gives you the computer ASCII code representing a letter. For example, seven white stripes, a red stripe and then two more white stripes represents 0000000100, the binary for four. Adding 64 to that gives 68, the ASCII code for the letter D."

#### kuririn

##### BARGeezer
TRF Supporter
Looks like somebody on the chute design team had a lot of time on their hands.

#### PatD

##### Well-Known Member
TRF Supporter
It amazes me what we can do with math. Here's a picture from the Mars Reconnaissance Orbiter, which had its camera pointed in just the right direction at the right time, to capture an image of Perseverance under its chute, descending toward the surface.

And here's a high res hazcam shot... beautiful, and it's from basically the lowest resolution camera on the rover.

Wow!!! That HiRise shot is spectacular!

#### PatD

##### Well-Known Member
TRF Supporter
Dare Mighty Things

"Internet sleuths claim to have decoded a hidden message displayed on the parachute that helped Nasa’s Perseverance Rover land safely on Mars last week. They claim that the phrase “Dare mighty things” – used as a motto by Nasa’s Jet Propulsion Laboratory – was encoded on the parachute using a pattern representing letters as binary computer code.

Reddit users and social media posters on Twitter noticed that the red-and-white pattern on the parachute looked deliberate, and arrived at the result by using the red to represent the figure one, and the white to represent zero.

Each of the concentric rings in the parachute’s pattern represents one of the words. The zeroes and ones need to be split up into chunks of 10 characters, and from that, adding 64 gives you the computer ASCII code representing a letter. For example, seven white stripes, a red stripe and then two more white stripes represents 0000000100, the binary for four. Adding 64 to that gives 68, the ASCII code for the letter D."
I'm sorry, that is waaaaaay beyond my geek level. I would have groked it if I could see binary in 3d. Nice job!
Edit: Yeah I know it really isn't 3d to examine, but damn!

#### Cape Byron

##### The BAR formerly known as Skippy-2
TRF Supporter
Looks like somebody on the chute design team had a lot of time on their hands.
Well, it's not like they have a social life...

##### Well-Known Member
TRF Supporter
Engineering behind the Perseverance Rover, comparison to that of its predecessor (Curiosity) and technology used on ISS:

#### Marc_G

##### Well-Known Member
I'm sorry, that is waaaaaay beyond my geek level. I would have groked it if I could see binary in 3d. Nice job!
Edit: Yeah I know it really isn't 3d to examine, but damn!
2D Radial Binary. Damn, that's far out into geekspace. Like something from Arrival, in terms of weird communication.

#### Cape Byron

##### The BAR formerly known as Skippy-2
TRF Supporter
Seriously @KC3KNM , people say the same about me!

My partner has asked me twice this year how many times I can watch the same Apollo missions. 6.023x10(23) apparently isn't funny...

*That 23 is meant to be a superscript but I can't work out how to do it... #nerdfail

#### KC3KNM

##### Well-Known Member
TRF Supporter
Seriously @KC3KNM , people say the same about me!

My partner has asked me twice this year how many times I can watch the same Apollo missions. 6.023x10(23) apparently isn't funny...

*That 23 is meant to be a superscript but I can't work out how to do it... #nerdfail
The frown response was in a joking manner, I’m in the same club

#### Cape Byron

##### The BAR formerly known as Skippy-2
TRF Supporter
The frown response was in a joking manner, I’m in the same club
It's a good club. Very few biters.

##### Well-Known Member
TRF Supporter
There is a data bottleneck in getting information from Mars. The DSN only has limited capability and must service all missions on all planets, the sun and anywhere else in space. At least they are using MRO as a data cache and relay and can get decent data rates when the orbiter is visible from Earth. This is becoming a bigger problem as more countries become active and expect the DSN to service their missions.

For a look at their current links, see here:
https://eyes.nasa.gov/dsn/dsn.html
The data transmission rates from MRO are not that bad, around 2.0 Mb/sec when I looked earlier.
For reference, Voyager 1 is only 160.0 b/sec:

Most of the comms are over either x-band (8-12 GHz) or S-band (2-4 GHz) frequencies. DSN uses lower ends of both.
Downlink data transmission for DSN Telemetry Packet Service goes upto 10 Mbps for deep space transmission, and 150 Mbps for near Earth Ka-band.

DSN does support Multiple (2+) Spacecrafts Per Antenna (MSPA) for downlink, as long as all devices lie within the beam width of a given antenna, and transmit on different frequencies. For uplink, only one device at a time can receive the commands.

More data here:

Man, if only somebody was putting a broadband constellation in space....
Unfortunately, the constellation is around the wrong planet to be of help to Perseverance.

#### dhbarr

##### Amateur Professional
The data transmission rates from MRO are not that bad, around 2.0 Mb/sec when I looked earlier.
For reference, Voyager 1 is only 160.0 b/sec:

View attachment 452108

Most of the comms are over either x-band (8-12 GHz) or S-band (2-4 GHz) frequencies. DSN uses lower ends of both.
Downlink data transmission for DSN Telemetry Packet Service goes upto 10 Mbps for deep space transmission, and 150 Mbps for near Earth Ka-band.

DSN does support Multiple (2+) Spacecrafts Per Antenna (MSPA) for downlink, as long as all devices lie within the beam width of a given antenna, and transmit on different frequencies. For uplink, only one device at a time can receive the commands.

More data here:

Unfortunately, the constellation is around the wrong planet to be of help to Perseverance.
I forgot all improvements in bandwidth to DSN must be made at the far end only, thanks for the reminder :-D

#### mach7

##### Well-Known Member
Does anyone know what rocket fuel the descent stage used? In the video no rocket plumes can be seen.

I see 3 spherical tanks and one cylindrical tank on the descent stage. I'm assuming one contains helium or nitrogen to pressurize the rocket motors, one is probably oxygen, and the 3rd is the fuel? Would the cylindrical tank be a fuelcell?

I've looked at the available info, but can't find what the fuel was.

Thanks

#### Marc_G

##### Well-Known Member
Does anyone know what rocket fuel the descent stage used? In the video no rocket plumes can be seen.

I see 3 spherical tanks and one cylindrical tank on the descent stage. I'm assuming one contains helium or nitrogen to pressurize the rocket motors, one is probably oxygen, and the 3rd is the fuel? Would the cylindrical tank be a fuelcell?

I've looked at the available info, but can't find what the fuel was.

Thanks
Hydrazine. I think it was discussed in the press conference. No visible flame typical for this scenario.

#### mach7

##### Well-Known Member
Ah, that makes sense.

Thanks much.

#### Marc_G

##### Well-Known Member
General principles of operation here:

Thanks!

#### OverTheTop

##### Well-Known Member
TRF Supporter
The data transmission rates from MRO are not that bad, around 2.0 Mb/sec when I looked earlier.
Using MRO as a relay has really improved the situation around Mars. That does have a decent data rate and acts as a data cache and relay, greatly improving the throughput of the DSN in that locale. They don't need to have to wait for both Earth and Mars to be facing in the right direction, so transmission windows are more readily available.

#### georgegassaway

Hope that the copter works well, when they get around to trying it. It will only "hop" for about 90 seconds, and charge for a day or more before the next hop.

Anyway, here's this:

#### Marc_G

##### Well-Known Member
I know the rover's mission is essentially to look for ancient microbial life, but I keep hoping it will scrape a sedimentary rock and find something like a clam shell, ammonite, or the like... How cool would that be?

#### dhbarr

##### Amateur Professional
I know the rover's mission is essentially to look for ancient microbial life, but I keep hoping it will scrape a sedimentary rock and find something like a clam shell, ammonite, or the like... How cool would that be?
Anything more complex than algae or fungi would be mind-blowingly awesome.

#### NOLA_BAR

##### Well-Known Member
TRF Supporter
I know the rover's mission is essentially to look for ancient microbial life, but I keep hoping it will scrape a sedimentary rock and find something like a clam shell, ammonite, or the like... How cool would that be?
If they find anything that resembles stromatolites or layered algal mats, that would blow the top off.

#### NOLA_BAR

##### Well-Known Member
TRF Supporter
Spirit rover actually found some very interesting hot spring deposits that closely resembles algal growths. There was a proposal to send Perseverance back to Gusav Crater, but that wasn’t going to happen.

#### NOLA_BAR

##### Well-Known Member
TRF Supporter
Scott Manley gives a good breakdown/review of the landing.