And read about how it will use Terrain Relative Navigation to find a safe landing spot: https://www.jpl.nasa.gov/news/a-neil-armstrong-for-mars-land...
Perseverance is phenomenally complex, its Sample Caching System alone contains 3,000+ parts and two robotic arms. So exited for all the sciencing this nuclear-powered, sample-drilling, laser-zapping behemoth can do when it joins its friends on the only planet (known) to be inhabited solely by robots.
Edit: Percy is about to release its two 77 kg Cruise Mass Balance Devices (is this what NASA calls 'weights'?) to setup the right lift-to-drag ratio for entry. Mars InSight will be listening for the 14,000 km/hr impacts of these weights, providing useful calibration data. We wrote about this in this week's issue of our space-related newsletter, Orbital Index - https://orbitalindex.com/archive/2021-02-17-Issue-104/
https://www.simscale.com/blog/2017/12/nasa-mars-climate-orbi...
I'm sort of surprised we don't yet have ML powered "de-accent-ization". His french accent isn't hard to understand at normal speed, but when I set it to 1.5x or 2x speed it becomes hard to decipher in a way native speakers usually are not. If there was just a button (for him or me) to hit to tweak the sounds a bit to reduce the accent, I bet this problem would go away.
If the speech recognition / subtitling algorithm can't understand the nuances of the language, that's going to be a problem anyway... accented pronunciation is so multidimensional, you're pretty much going to have to transcribe syllables/phonemes first...
Some of the other videos on this channel are just as in-depth: the ones about the plumes/exhaust of rocket engines as well as star occlusions are incredibly detailed.
They put those in to make the probe seem higher-quality. They got the idea from Beats headphones.
Well no, the Cruise Mass Balance Devices are intended to Balance the Mass of the spaceship during Cruise conditions. That these Devices are single-part and constructed out of a single chunk of metal each should not be construed as merely being 'weights'. :)
Atmospheric drag force center of drag and center of gravity to line up on a same axis, which force the craft to fly slightly sideways if spacecraft isn't perfectly balanced. Done carefully, it leads to direction of flight being slightly sideways, which is awkward but basically same as having lift towards that direction. Add roll control thrusters into the mix, and you get a really crude glider, with fixed pitch force, zero yaw control and barely controllable roll. With JPL-class engineering, such a spacecraft will be capable of actively correcting landing location.
I guess what's surprising is that they needed that much weight (140+kg seems like a lot?) and couldn't redistribute existing componentry; guess the knapsack algorithm wasn't good enough, or that they just couldn't break up enough pieces?
And yes, Cruise Mass Balance Devices sounds like the type of name a tired engineer would come up with to convince upper management...lol
"At 09:00:46 UT Sept. 23, 1999, the orbiter began its Mars orbit insertion burn as planned. The spacecraft was scheduled to re-establish contact after passing behind Mars, but, unfortunately, no signals were received from the spacecraft.
An investigation indicated that the failure resulted from a navigational error due to commands from Earth being sent in English units (in this case, pound-seconds) without being converted into the metric standard (Newton-seconds).
The error caused the orbiter to miss its intended orbit (87 to 93 miles or 140 to 50 kilometers) and to fall into the Martian atmosphere at approximately 35 miles (57 kilometers) in altitude and to disintegrate due to atmospheric stresses."[0]
[0] https://solarsystem.nasa.gov/missions/mars-climate-orbiter/i...
As noted in other comments, NASA (like the rest of the United States [1]) does use the metric system.
But it doesn’t matter. Nothing about the metric system makes it uniquely suitable to landing on Mars. Or space travel in general. What matters is a consistent standard.
Internally NASA could use Armstrongs. Where 1 is the weight or height of Neil Armstrong at KSC on July 16, 1969 at 13:32:00 UTC. It doesn’t matter. As long as it is consistent.
[1]: https://en.m.wikipedia.org/wiki/Metrication_in_the_United_St...
With metric it's a matter of shifting the decimal.
How much is a sixteenth inch anyways.
During the stream, you can hear the various teams giving measurements in metric, whilst the media gave coverage in imperial.
It's a pretty interesting video from that perspective, as you can hear the two "realities" being translated for the intended audience.
So basically TERCOM from cruise missles but used on space crafts? All you need is a radar countour map of the area and it can automate it's way to the endzone.
[0] https://youtu.be/TUd604rBR6I?t=643
[1] https://www.scientificamerican.com/article/the-first-100-day...
Is it the idea that life could originate elsewhere and that there might really be aliens?
Or is it the idea that Mars could support some sort of colony?
Or the hope of completely novel microbiology?
Any one of these things would be a massive boon to our understanding of life throughout the solar system and broader universe, right down even to here on Earth. All three of them would arguably mark a new era in Earth's history.
Looking forward for the next landing in May of the Chinese rover and all the science these robots will produce. Also, the test of Ingenuity, the helicopter, will be very interesting to watch, that could really pave the way for a different exploration style in the future.
And finally, maybe the next transfer window will already see some Starships, that would really change everything.
What would you ballast a starship with for the practice missions?
Useful materials which might survive a RUD and aim for someplace near a likely landing zone? If you crash the parts of a milling machine, a lathe, some tooling, some assorted metals stock, and a bunch of assorted wire, well sure you just cleared out a machine shop auction, but maybe there comes a day when an early Mars colony would be thrilled to go clean up your “landing” site.
Basically all of the history of science until 200 years ago was figuring out "mine and extract" and the course of civilization is very much linked with the price & quality of metal structures they could produce. But it's gotten so good we take it for granted.
However that is because of gigantic plants situated in specific areas where energy is cheap that do this thing at an amazing scale.
Aluminum is cheap as chips, except that it used to be more expensive than platinum (and at a much higher impurity ratio than the stuff we use for baking or for making cheap cases).
Heck, gold is "a thing" because we could purify and mold it without bringing it to a melting point and it was, for a very long time, the only metal available to us to do anything with, way before the bronze age.
And the problem with the refinement process is that you can't really "be smart" about it, reaching very high temperatures is one of those things you can't really scale down in an efficient way. You'd have to propel 100,000 tons of factory to mars in order to efficiently refine anything remotely close to the metals we had access to 100 years ago.
Which is not to touch on the mining bit, that is in itself very complicated (see how slowly and shallowly rovers are currently able to drill).
Are there workarounds for this? Maybe, I don't think anyone knows them though, they are not the kind of thing that's within easy reach. Maybe if we happen to stumble upon large reserves of bismuth or lead or gallium or mercury close to the surface of Mars, and build a whole branch of engineering around using those to build machinery... ? But my limited knowledge of geophysics and geology tells me that finding those in large amounts is very unlikely.
For reference, if you take an oven, that can reach, say, 450 degrees celsius (home) and up to 700 (industrial). Those aren't enough to refine any "useful" metal (e.g. iron) and building them requires materials that were produced at 1500+ degrees.
IANAChemist/IANAMaterialScientist/IANABlacksmith though, so take with a spoon of salt.
Everything happened correctly. :)
That is Rob Manning, an absolute legend! Here is an interview with him from a few years back: https://solarsystem.nasa.gov/people/2280/rob-manning/
He also wrote this great book: https://www.amazon.com/Mars-Rover-Curiosity-Curiositys-Engin...
Can't wait till they start posting raw images :)
When you do computer vision, the first step you do is convert your color image into a black and white image, and run your CV algorithms on the black and white image. This is because when you're looking at objects and shapes and stuff, it's contrast that tells you where the boundaries between things are. This is true even in a human world of human objects, which tend to be many colored. It's even more true on Mars where basically everything is varying shades of orange. So having color doesn't help a whole lot, and you also have to do the additional step of converting the color image to black and white, which takes CPU power and adds latency. Remember, the purpose is hazard avoidance- latency is bad.
Additionally, color camera sensors aren't actually color sensors. They're black and white sensors. In front of every pixel on the black and white sensor is a filter that is either red, green, or blue. Pixels are grouped into sets of four, and there are two pixels with green filters, one pixel with a blue filter, and one filter with a red filter. (sometimes one of the green filters is omitted, giving red, green, blue, and b&w, or sometimes one of the green filters is a filter that allows IR, or something like that.) So if you have a 16MP camera, the camera has 8M green, 4M red, and 4M blue pixels. This means two things; first of all, if you just wanted a black and white image in the first place, a color sensor gives less detail than the equivalent black and white sensor, and second, you need to do additional processing to convert the raw output from the sensor into an image that's usable for anything. The additional processing adds latency.
The lower "HazCams" hazard avoidance cameras (which captured those initial photos) are there to detect hazards (rocks, trenches, etc.). They are stereoscopic, lightweight, and high resolution.
My guess is that using color sensors would have either increased the 3D mapping precision or added weight/power/bandwidth requirements, or otherwise been less robust in that environment.
Those cameras were also pre-deployed for the landing phase and likely transmit more quickly due to the lower data information. The other cameras were shielded for the landing phase.
The navigation and other cameras are in color, and I expect we'll be seeing better images shortly.
[1] This comes to mind whenever a question like that is asked: http://4.bp.blogspot.com/-CWM1zDcmWXs/TroD0VsX4WI/AAAAAAAAAV...
I think you meant to say decreased? In which case I think you would be correct! Camera pixels are made up of these things called photosites which don't by themselves record color, only brightness. In order to record color information, the photosites are placed behind a Bayer filter[1], which effectively reduces the resolution of the camera by 3, because in order to get the color of a pixel you need its red, green and blue component. Bayer filters also frequently have a small blurring filter in front of them to make sure that nearby photosites with different color filters get the information they need.
If you're looking for the highest resolution image possible, black and white is the way to go!
These are hazard cameras, designed to be inputs into the guidance algorithms on board. It might make sense for such a camera to be B/W to reduce on board processing required. There's also a glass cover on them, and a lot of dust from the landing, so that may be obscuring true color if the cameras do in fact take color images.
Also they may have just transmitted a lower quality B/W image to get something back to Earth quickly, since higher res images take longer to uplink.
Also doesn't help that there is a (transparent) lens cover in front of the lens obscuring the view.
Elon Musk needs to provide some Starlink sats for a better connection.
It seems that NASA is being awesome and making all raw images available as they get them. So far just the 2-ish.
Guessing its black and white/high contrast to help see rocks etc. And probably much lower res, smaller file size too for transferring.
Anyone seen anything about the precise location yet?
> UNOFFICIAL but it looks like Percy landed right on the edge of the Mafic Floor Unit, with older (probably sedimentary) rocks that were buried by it only a short drive away.
EDIT: Congrats to the team! Great success
I'm looking forward to what Perseverance will teach us.
That would help to make the landing quite a nerve racking event.
Sitting in any closed space like that one, with other people, masks or no, is stressful right now. It's a shame that NASA can communicate with a rover 125 million KM away but their staff have to all be crammed into one small enclosed space. You'd think we'd be able to communicate just as effectively over several kilometers.
I imagine that people will look back on videos from this time period where ~3M people died (mostly unnecessarily) and wonder what on Earth people were thinking, carrying on like that.
Hope Percy isn't running Webex.
EDIT: It's a 200mhz CPU alongside 256mb of ram. https://mars.nasa.gov/mars2020/spacecraft/rover/brains/
The EDL phase was quite complex this time. The cameras took pictures of the surface while landing and compared them to the maps it had from orbital missions. Using these two, it decided in realtime, which place would be the best of the its landing. This made it possible for it land in a more difficult terrain, like the crater where it landed.
Great job, mission!
Hmm, another: Given that it's roughly a decade since MSL Curiosity, what were y'all (Perseverance team members) doing when Curiosity launched and landed? How many of today's team were in school back then, or what's the generational turnover and overlap like?
What's everyone's "favorite" failed Mars mission that would've changed everything if it'd succeeded?
Also, do the Rover Drivers still live on the Mars time that makes their working hours shift by 45 minutes every day, like in the good old MER days ? ;-)
I couldn't help but wonder, while I watched the feed: What are the people in mission control doing during the landing?
Obviously they're monitoring telemetry - but what else? Presumably the time delay precludes them triggering anything critical manually, and making post-launch software changes would be frowned upon?
Thanks for your efforts towards the fantastic result today.
Will this rover make contact with its forebears at some point?
Or are you reffering to something else?
To their credit, I've watched NASA spend decades getting better at Internet services and generally being an online presence. Improvements year-over-year have been noteworthy. But I still have to chuckle a little bit that they triggered a DDOS protect by name-dropping themselves.
Ad Internet Per Aspera, you crazy spacers ;)
- Flying an experimental helicopter on Mars
- Gauging the habitability of its landing region (Jezero Crater, a paleo-lakebed with preserved river delta and sediments) and hunting for ancient microbial biosignatures (with lasers!)
- A drill (that can cut intact rock cores, rather than pulverizing them like Curiosity)
- An ISRU experiment that makes oxygen from CO2
- Way more advanced autonomous navigation
They were showing off a model of the rover, I did not realize just how large this one is!
I am amazed at what humans have been able to achieve in short time since the Industrial revolution.
After all the negativity of last few months, this brings so much hope.
Waiting for the first human foot touch down on Mars in my lifetime.
It started with ~800 lbs of hydrazine fuel on board that had to slow tons moving at 200 mph to a dead stop, and then hover for 10+ seconds while the lander spun down; and then boost away and crash. ("Crash-land" sounds like entirely more control than what really happened.)
It is just amazing to think that a robot is roaming around in Mars, and a second one might be joining today.
(I'm totally kidding; what they've accomplished is incredible!)
I wonder if I can cop a replica somewhere, and how it would fly considering it is built for martian air
TL;DW: Martian atmosphere is so sparse that it's equivalent to flying at 100,000 feet on Earth. (The altitude record on Earth is 85,000 feet, set by the SR-71.) In order to fly at all the blades have to spin at nearly the (Martian) speed of sound. The drone wouldn't fly on Earth because the atmosphere is so dense that the blades would never make it up to speed.
The A-12 Arkangel flew higher (95,000 feet) and faster, but was short-lived and so highly classified that it doesn't hold any "official" records.
And a MiG pilot flew up to 123,000 feet, but only on a ballistic trajectory, it wasn't a sustainable altitude.
1. See page 20 of the launch press kit: https://www.jpl.nasa.gov/news/press_kits/mars_2020/download/...
Sure, for stuff you can reasonably test in Earth gravity and atmosphere you can just weld stuff together in a field and then fly it until it stops crashing. Thats a case when you can iterate quickly and relatively easily with lots of COTS stuff.
For comparison: SpaceX's entire Falcon 1 program cost $90M over 6 years. That was to develop two new rocket engines (Merlin & Kestrel), build out the launch site on Omelek Island, and launch five times.
I'd bet on it making 20+ at evens.
And its got to be tough conditions for the battery, low temperatures and probably deep discharges to make the most of it.
Rovers with solar panels deal with the dust by waiting for a storm to blow it away.
I'd expect it to kick up a fair bit of dust on landing. But I suppose that's something else that'll behave a bit differently on Mars to what we'd expect in Earth's atmosphere.
https://ttu-ir.tdl.org/bitstream/handle/2346/74036/ICES_2018...
Mars may become some sort of tax haven, and companies will move their HQs to Mars to avoid taxes. But then, you won't be able to receive correspondence on Mars.
Then, extradition from Mars would be so expensive it would not be even feasible.
Will have to update it if images from Perseverance become available through the NASA Open APIs.
https://simon-lang.github.io/mars-rover-image-viewer/#/colle...
What does NASA have to show for a decade of work, since Curiosity landed in 2012? A toy helicopter, a drill that poops pellets. Billions of dollars and millions of man-hours later, this is the only progress.
The truth is NASA has become extremely conservative and slow. Compare this to the moon landing. NASA went from one man in Earth orbit in 1961 to people walking on the moon as a matter of routine in 1969. That is the pace needed for serious technological progress in space.
We must let NASA die, and let others pursue these feats, people who have a real passion for space exploration. If NASA had only a bit of passion, they would have sent men on this mission, based on all the learnings from Curiosity.
Defund NASA.
But in reality, it obviously didn't fly in a straight line, Looks like it traveled closer to 292 million miles[2], so more like 60,000 mph.[3]
[1] - https://www.wolframalpha.com/input/?i=127800000+miles%2F4881...
[2] - https://mars.nasa.gov/mars2020/timeline/cruise/
[3] - https://www.wolframalpha.com/input/?i=292526838+miles%2F4881...
"Well, officer, perhaps to you it seemed like I was speeding there..."
- Monty Python.
https://twitter.com/NASAPersevere
I'd bet they post the first high-res pictures once they arrive. The link from Mars to earth is sending a lot of information about what just happened, so understandably bandwidth is pretty saturated
[0] https://mars.nasa.gov/mars2020/spacecraft/rover/communicatio...
edit: the closest thing ive found is data.nasa.gov. how hard is it to just generate a fucking simple html website with chronologically ordered images? this is bullshit
edit: ok, here is almost exactly what i wanted: https://mars.nasa.gov/mars2020/multimedia/raw-images/ the internet really sucks compared to what it might be... go to nasa.gov and click percy mission from the drop down and it takes you to a part of nasa.gov thats filled with eye-cancer tiles and javascript with sensor imaging mixed in with PR images and promotional material. but they tuck the (sort of) clean, organized data into some other website basically? maybe its a small gripe but this way of doing it is disorganized and infuriating.
edit: wow, this website is fucking amazing! you can see the real-time position of all nasa mars vehicles 3D google earth style: https://mars.nasa.gov/explore/mars-now/ anyone who has not looked around in mars.nasa.gov should bookmark that right away
curiosity shots:
https://mars.nasa.gov/raw_images/895098/?site=msl
https://mars.nasa.gov/raw_images/896437/?site=msl
https://mars.nasa.gov/raw_images/895971/?site=msl
https://mars.nasa.gov/raw_images/895971/?site=msl
https://mars.nasa.gov/raw_images/895077/?site=msl
https://mars.nasa.gov/raw_images/891625/?site=msl
https://mars.nasa.gov/raw_images/888957/?site=msl
Maybe my question makes more sense in the case of "X is happening right now", because then I should either understand "we infer that X should have happened right about now" or "we have confirmed via signal that X has happened", and that's a big big difference.
I know in some cases they explicitly say the latter, so I guess my real real question is, do they just keep the communication delay implied in all countdowns & references in discussion, to avoid confusion?
(ETA: No need to let me know about simultaneity problems in relativity — earth and mars are, relative to c and to macroscopic time scales, essentially not moving relative to each other AFAIK, so that simultaneity is essentially well-defined. My question was about a much more boring classical-universe problem.)
Ah great, that's a great phrase to make everything clear and provide a kind of "frame of reference" to think & communicate in. Always need these abstractions.
Still a very nice yet nerve wrecking idea to do it like this - you know the lander is on Mars now. But is it safely on the ground or is there a third Shapirelli crater now ? You don't know! A huge relief in the end. :)
On the other hand, if you were on Earth and I was in between Earth and Mars, I would receive the data more quickly than you, and I could even watch it whiz by me on its way to you. The thing about relativity is that it’s... relative!
:)
According to the energy-time uncertainty principle we don't even know when exactly the RF waves that transmitted information hit the receiver on Earth either.
See for example [4] and [5].
[1]: https://en.wikipedia.org/wiki/Total_order
[2]: https://en.wikipedia.org/wiki/Partially_ordered_set
[3]: https://en.wikipedia.org/wiki/Java_memory_model
[4]: https://www.youtube.com/watch?v=UYZIHP120go
[5]: https://www.microsoft.com/en-us/research/publication/time-cl...
(Not trying to be judgy. People just seem to forget about the gender neutral use of "they".)
And even that is not correct. Events happening propagate with speed of light - the event horizon. We can predict we will receive information of something happening, bit that's just prediction about future events, regardless of the location.
not in the true accurate to the picosecond sense of the word, no, but the exact word simultaneity is used when discussing number and density of satellites about a given latitude/longitude in the starlink beta program. Since they're LEO and orbiting at only 550 km, the satellites above a given spot on the ground vary greatly in the not-yet-complete sparse network.
Usually related to discussions of whether a beta test customer terminal will briefly hiccup and lose connection to its default gateway, or if somebody is at a sufficiently high latitude that they can have full coverage for all 86400 seconds in a day.
https://satellitemap.space/ has a good animated visualization of this.
Apparently the latency time is currently 11 mins 22 seconds -- which is somewhere near the average. It goes from under 4 mins to over 22mins depending on distance.
With your personal light cone, it's fine to equate "now" with what you see in the moment. It just has to be clear what you mean for situations where communication might be ambiguous. If you have a person on mars, be sure to be precise what you mean when you tell them to do something in five minutes, when they receive the message they won't know if you mean five minutes after they receive the message or anywhere between 17 minutes before and 2 minutes after they receive the message.
When you get into relativistic speeds (and especially very short time intervals), nobody can even agree on when something "actually" happened, different observers have different opinions about what happens when even after you account for light travel time.
And there is no concept of now in a significantly distant location. Related video: https://youtu.be/pTn6Ewhb27k
Put another way, simultaneity is perfectly well defined in a single inertial reference frame, and for purposes of my question, earth and mars can be considered to be relatively motionless.
Simultaneity is not “perfectly well defined in a single intertidal reference frame”. That is just a convention.
If the RTT of earth to Mars is 20 minutes, then we can say that it takes us 20 minutes for our message to reach the rover, and the rover’s message arrives instantly, and that’s a consistent definition of simultaneity.
https://www.pitt.edu/~jdnorton/teaching/HPS_0410/chapters/si...
Not enough info, too much "personality" and "team work". Waste of time watching it really.
SpaceX doesn't do this. They are always top quality. Adults doing professional things in space, that to me is more inspiring to children and young adults.
Can't they have an adult stream and one dumbed down for the children if they really think these things should be dumbed down.
It was better than ESA I guess
Even though "children asking questions" may be less appealing to children than "adults asking questions", the former might get aired anyway because it's more appealing to the adults that make children's programs.
Meanwhile, SpaceX takes half a dozen tries before managing to do the same on a fully known environment on Earth.
SpaceX being private has a much larger cushion for failure. Elon will keep funding it far longer than congress would Nasa is my guess. If SpaceX loses some rockets that's the cost of business, of course once those missions are manned it's a huge difference but until then I think it's not really comparable.
Also, SpaceX IS mostly funded by NASA anyway as a government contractor. SpaceX exists because the government wanted to create a private space market. Strangely thank George Bush for it. https://www.fool.com/investing/2017/02/05/how-profitable-is-...
As you can see, SpaceX was so cash strapped in 2017 it obviously didn't go to mars in 2018 as they wanted. Also notice Elon didn't fund that trip (otherwise it would have happened). There is no way he would risk HIS own money on that.
This would mean that SpaceX would need to develop and fund Dragon 2 propulsive landing on their own, with only real mission fully requiring it being Red Dragon.
In the end it was much easier to just drop the whole thing, especially with the much more perspective Starship on the horizon.
SpaceX is trying to land things the size of buildings.
Let's just say it's a very different problem.
If you though there is someone in Boca Chica flying Starship remotely with joystick and steady hand, I'm afraid I need to disappoint you.
https://en.wikipedia.org/wiki/Mars_Climate_Orbiter
> The spacecraft encountered Mars on a trajectory that brought it too close to the planet, and it was either destroyed in the atmosphere or escaped the planet's vicinity and entered an orbit around the sun. An investigation attributed the failure to a measurement mismatch between two software systems: metric units by NASA and non-metric ("English") units by spacecraft builder Lockheed Martin.
https://en.wikipedia.org/wiki/Mars_Polar_Lander#Landing_atte...
> Communication was expected to be reestablished with the spacecraft at 20:39:00 UTC after having landed. However, no communication was possible with the spacecraft, and the lander was declared lost.
Actually it is not mad - becase it exploded into millions of pieces due to the leaky fuel system...
Let's not diminish ether's breakthroughs, but financial isn't one of SpaceX's.
The size of the objects that SpaceX is landing is much larger. The approach that was used here for Perseverance (Skycrane) would not work for larger ships, like those required for a human mission. Just like the previous approaches, e.g. Lithobraking with Spirit and Opportunity, would not have worked for Perseverance.
Larger objects are much more difficult to land. Simply put, while mass will increase by the power of three, surface area, which is used for aerobraking only scales by the power of two, relative to size.
In order to land something large enough to carry and support humans (10-100t), you need hypersonic retropropulsion. Guess who was the first to achieve this? SpaceX. And they remain the only ones. When they light the three engines for the entry burn the earth atmosphere is very similar to the relevant section of the future Mars decent. By developing the first stage landing of Flacon 9, they solved one of the biggest development challenges for humans landing on Mars and it was not by accident. NASA was very happy to get that data and helped them collect it with their chase planes.
That's why you always see parachutes + something else for Mars EDL - parachutes + rockets, parachutes + airbags, parachutes + skycranes. And in Starship case, high speed glide and speed shedding with propulsive landing at the end.
Not to mention weird, considering how successful SpaceX has been at dominating the commercial launch sector.
(Update: sorry, by "this" I mean the parent comment.)
