All these worlds are ours
July 30, 2020 7:56 AM   Subscribe

The robotic conquest of Mars continues with 3 new missions officially on the way! The United Arab Emirates launched the first Arab interplanetary probe, called Hope, on July 19, China sent Tianwen-1 off on Jul 23, which includes an orbiter and lander, and NASA has followed up with the Perseverance rover, carrying the Ingenuity helicopter. All of this is paving the way for eventual crewed exploration of the red planet!
posted by Brandon Blatcher (27 comments total) 27 users marked this as a favorite
 
In a first, Perseverance is equipped with microphones. We will be able to hear what Mars sounds like.
posted by Thorzdad at 8:08 AM on July 30 [19 favorites]


Bossa Nova, I am hoping!
posted by Meatbomb at 8:14 AM on July 30 [10 favorites]


The "Tech Specs" for the Ingenuity helicopter are pretty interesting, for helicopter nerds anyway, and show just how "on the edge of possible" this is.

It has a roughly 1.2 meter rotor diameter and will fly up to 5m above the ground, so I think that means it's flying out of ground effect, but I'm guessing will only go up that high with translational lift helping out, and won't hover at that altitude.

It says average power during flight is 350 watts (so call it 1/2 a horsepower) and its weight in Martian gravity will be 1.5 lbs... so about 3 lbs per horsepower. Compare that to something like a Robinson R22 on Earth at around 10 lbs per horsepower at maximum power, but that's for a much larger helicopter. Any drone nerds here know this figure of merit for a similar weight drone on Earth?

Maximum flight time is 90 seconds and it can go 300m in that time, and it can do that only once per day. Getting and storing enough power in a lightweight battery seems to be a real problem!
posted by FishBike at 8:54 AM on July 30 [3 favorites]


For pedantry's sake, two other US Mars missions had microphones - the Mars Polar Lander and the Phoenix Lander. MPL failed, and the Phoenix microphone was never used as the camera instrument it was mounted on had a potential mission-risking issue and was never turned on.

So, this will certainly be the first rover with a microphone, and hopefully the first successful mic on Mars. Here's hoping we can listen to the copter take off...
posted by foonly at 9:00 AM on July 30 [10 favorites]


Beautiful launch this morning. Watching on my iPad in bed, I saw a rocket take off for Mars that will maybe deliver a helicopter to fly over another world. Sometimes the promised future actually happens.
posted by Capt. Renault at 9:14 AM on July 30 [11 favorites]


One of my favourite parts of the Cassini mission to Saturn was the recording of Huygen's descent into the atmosphere of Titan (even though it was just the sound of wind rushing by the mic). So I'm looking forward to hearing Mars.
posted by giltay at 9:18 AM on July 30 [8 favorites]


Maximum flight time is 90 seconds and it can go 300m in that time, and it can do that only once per day. Getting and storing enough power in a lightweight battery seems to be a real problem!

Mars only gets ~550W/m^2 of solar irradiance and the panels are small and will often be dusty.
posted by Your Childhood Pet Rock at 9:46 AM on July 30 [1 favorite]


If you're wondering how a helicopter can work in such thin atmosphere, the blades spin at 2400 rpm which is about five times faster than is typical for an earth helicopter. This is limited by keeping the tips subsonic. Speed of sound is slower on Mars so you can spin faster while the tips stay at mach 0.7.
posted by atrazine at 9:48 AM on July 30 [12 favorites]


Well, it's five times faster than is typical for a full size Earth helicopter. A Goblin 770 with a similar ~1.5m disc recommends a head speed less than 2000rpm. I'm actually sort of surprised Ingenuity isn't running faster given the atmosphere.

I almost wonder if the power requirements aren't all that dissimilar between Ingenuity and common earthbound RC helicopters though - the goblin wants 12s-14s 5000mAh batteries, so something like 250Wh (I think? I'm used to thinking about much smaller batteries, and I stopped doing power calculations years ago), which it drains in 6 or 7 minutes?

Mind you, we can use a much bigger charger on Earth...
posted by Kyol at 10:07 AM on July 30 [1 favorite]


The flight characteristics of Ingenuity were discussed in this Previously, including a link to a design and testing paper.
posted by zamboni at 10:14 AM on July 30 [3 favorites]


Please note that the field refers to "crewed" spaceflight now, not "manned," though a lot of the media still seems to think it's 1969. Sigh.
posted by rikschell at 10:46 AM on July 30 [16 favorites]


Duh, good point, will ask mods to change!
posted by Brandon Blatcher at 10:54 AM on July 30


This is limited by keeping the tips subsonic. Speed of sound is slower on Mars so you can spin faster while the tips stay at mach 0.7.

I think you have that backwards. Slower speed of sound means mach 0.7 on Mars is slower than on earth. Unless I am misunderstanding what you are saying.
posted by JackFlash at 11:31 AM on July 30 [1 favorite]


the panels are small and will often be dusty.

The panels are strapped to a helicopter, so dust accumulation may not be a concern.
posted by justsomebodythatyouusedtoknow at 12:44 PM on July 30 [1 favorite]


We will be able to hear what Mars sounds like.

If we start hearing any Holst, I'm gonna be verrrrrrrrry concerned.
posted by Greg_Ace at 12:48 PM on July 30 [11 favorites]


> Mars only gets ~550W/m^2 of solar irradiance

Huh, that's only half of Earth's (~1000 W/m^2).
posted by genpfault at 12:49 PM on July 30


Mars is about 51% further away from the sun than Earth is.

1.51 * 1.51 = 2.28

1/2.28 = about 44%

The inverse square law is...unfortunate.

The saving grace is that the much thinner atmosphere lets more light through.
posted by Hatashran at 1:10 PM on July 30


the panels are small and will often be dusty.

The panels are strapped to a helicopter, so dust accumulation may not be a concern.


That is such a good point, justsomebodythatyouusedtoknow!

Haven't at least a couple of our previous probes been killed by dust storms?

I know it must have been infeasible this time around, as well as undesirable from a standpoint of exploring as much new territory as possible, but wouldn't it have been cool if this baby could have blown the dust off a previous probe's solar collectors and revived it?

Maybe this probe's copter could blow dust off the probe's collectors, and future probes could include a collector cleaning drone as a default.
posted by jamjam at 1:54 PM on July 30 [2 favorites]




The panels are strapped to a helicopter, so dust accumulation may not be a concern.

The specs say it can get a 90s flight from a Martian day of charging, so it has to charge while on the ground and could still get dusty.
posted by EndsOfInvention at 3:12 PM on July 30


I wonder how many PI's with rejected proposals for sub 5lbs instruments have pictures of that helicopter on their dartboards.
posted by 3j0hn at 7:06 PM on July 30 [2 favorites]


Maybe this probe's copter could blow dust off the probe's collectors
While the last NASA Mars probe, INSIGHT, was solar powered, the rovers Percy and Curiosity (on which Percy's design is heavily based) are both powered by a ~100W Plutonium RTG and they do not have solar panels at all.

The helicopter is the only part this mission is solar powered.
posted by 3j0hn at 7:26 PM on July 30


We will be able to hear what Mars sounds like.

Just lots of guys who shake their heads rhythmically to resound.
posted by rodlymight at 9:06 PM on July 30 [1 favorite]


I think you have that backwards. Slower speed of sound means mach 0.7 on Mars is slower than on earth. Unless I am misunderstanding what you are saying.


oh yeah, I do actually.
posted by atrazine at 12:55 AM on July 31


So I blocked the drain with my towel, then blocked the rover with my satchel, right? So I press the button to get another, and SOME F*CKING HELICOPTER shoots out and snatches it out of the air!?!
I give up, am going back to Zork.
posted by bartleby at 2:35 AM on July 31 [8 favorites]


Just lots of guys who shake their heads rhythmically to resound.

Ack ack, ack-ack!
posted by Greg_Ace at 1:25 PM on July 31 [1 favorite]


Perseverance is equipped with microphones. We will be able to hear what Mars sounds like.

Faint, distant moans of “Ulla ulla ulla ulla”, slowly getting louder after dusk the first night.
posted by cenoxo at 8:50 AM on August 2 [1 favorite]


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