« first day (2863 days earlier)      last day (66 days later) » 

1:39 AM
@ymb1 I haven't composed the airplane question yet, but I've asked this:
0
Q: Could the Mars helicopter Ingenuity have been test-flown outdoors at JPL just for the heck of it? (not that they would)

uhohThe Ingenuity helicopter that has flown on Mars is designed for roughly 0.01 bar pressure and a colder atmosphere made of mostly CO2. See links (including video) in this answer to What JPL laboratory is this exactly, and what are the functions of these amazing-looking control panels? in Space SE ...

 
posted on May 19, 2021 by Thomas Burghardt

A Chinese Long March 4B rocket is expected to take a Haiyang oceanography satellite to… The post China to launch Haiyang-2D Oceanography Satellite from Jiuquan appeared first on NASASpaceFlight.com.

 
@uhoh UH OH:
2
Q: Can we bring a rotorcraft like Ingenuity to an altitude of the same pressure as the one on Mars?

GiovanniAt Perseverance's and Ingenuity's location the atmospheric pressure is about 750 Pa (0.11 psi). On Earth, we find that pressure about 110,000 ft high. If we built a copy of Ingenuity, could we bring it up there or close to that altitude? Probably not, because of the Earth's higher gravity and its...

just kidding :D
you forgot one bit, you wrote:
> The Ingenuity helicopter that has flown on Mars is designed for roughly 0.01 bar pressure
don't forget, and designed for Mars' gravity
In the first half of the video, it's not really flying, it's more like hopping up and then crashing back down. In the second half of the video, it is suspended from a cable that takes off 2/3rds of the weight in order to simulate Mars gravity. — Jörg W Mittag yesterday
 
@ymb1 I just added a link to that question in my comment below my question, thanks for pointing it out!
 
if I may, RE "(not that they would)": they test identical test-articles, as they do with the rovers, so it should be plausible
can't remember the proper term for identical test-articles
@uhoh was bound to have my own uhoh moment :P :D
 
I'm not sure what it is that I forgot exactly. They simulated reduced gravity with the cable simply to make the aerodynamic testing and qualification accurate.
 
1:50 AM
anyway I'm interested in its dynamics in thick atmosphere (should help!) and higher gravity (should make it harder), so +1 :D
 
Yes I know what you mean, there will very likely be a second copy or specimen (don't know exact word either) at JPL ready to go. When there are bugs or unexplained phenomenon, they often try to reproduce them in a lab on Earth whenever possible.
I think that the motor capabilities are a key part of the question. Can they get the right speed and right torque at the same tie with their current gearing.
 
they're direct drive, that was my first answer on Space.SE
 
btw sometimes they use balloons for gravity reduction
4
Q: Was this the only time that helium balloon was used to support deployed spacecraft appendages during testing on the ground in Earth gravity?

uhohWhat is this balloon for in this clean room and what is the proper name for the "stand" that is holding the satellite? shows the image below, and a comment below @OrganicMarble's answer there asks: Is ISRO the only agency to use balloons, or others too use them? which leads to the more general ...

Oh, I thought they were geared, You use the word "gear" four times in your answer which threw me off, but you do say "two brushless direct-drive propulsion motors" in your first sentence.
 
@uhoh you sure? I didn't use gear four times
just once: instead of a larger motor running both rotors with a >>gearing<< for the counter-rotation.
@uhoh lovely post
 
No I'm wrong; I'm merging tfb and ymb answers together because I'm doing three other things at the same time and didn't see where one ended and the next began.
 
1:59 AM
:D
 
I simply saw gears all over the place and panicked
But 1:1 could certainly be considered a "gearing ratio", and sometimes people will shorten that term to "gearing" even if there aren't any literal gears.
Anyway, it's time to get into gear myself and start the day's tasks. later!
 
1:1 would be for direct drive w/ counter rotation -- used in some multi-engine propeller planes; called handed-propellers
where one side turns the opposite to cancel the asymmetric torque
also the propeller is mirrored, so it's more expensive with more parts, hence some use it
 
18
Q: In helicopters, why not have electric motors controlling blade pitch?

DrZ214From my related question comes this idea of electrically controlled blade pitch in helicopters. Control linkages in helicopter rotors seem to be pretty complex. This surely incurs a lot of friction, especially if you realize that blades have to "flap" back and forth as they rotate around (in ord...

I guess you have a new answer for this one
although I guess they mean big, people-sized helicopters.
 
saw it, but not really, Ingenuity uses the motors to control the swash plate, which controls the rotor blades. That one when I skimmed it before wants a motor per rotor blade
to me, so many obvious problems with that, not least of which the mismatch that will happen
for some reason I saw it recently, thought it a new question, but wow it's from 2015
the answers already cover the plurality of problems :D
not going to keep you sorry :D talk to you soon!
 
 
11 hours later…
1:39 PM
just wondering how is it with the clear not a dupe reason, it gets closed: space.stackexchange.com/q/52141/32596
 
2:11 PM
Ryan Donovan on May 19, 2021
This is a story about trying to rethink complex systems: the challenges you face when you try to rebuild them, the burdens you face as they grow, and how inaction itself can cause it’s own problems. When you’re weighing the risk and reward of replacing architecture, it can take several attempts to find a solution that works for you.
 
 
3 hours later…
5:29 PM
 
6:13 PM
-3
A: Is there independent evidence that China landed a robot on Mars in May 2021?

azotThe photos transmitted by the Viking 2 lander and those taken by the Chinese rover show quite different landscapes. They do not corroborate each other, also they should look similar, as long as they present the same Utopia Planitia. So, there exist no mutual independent confirmation of landings i...

funny thing is, if it's being faked, wouldn't they've matched the landscape :'D
confirmation bias all over that accept, sadly
 
6:46 PM
@ymb1 yup. I have voted to delete as a non answer
 
 
3 hours later…
9:44 PM
0
Q: Will JWST have fewer observing sessions of much longer duration compared to Hubble?

uhohIn The Observatory @Donald.McLean linked to Scientists will peer at first galaxies with James Webb telescope which says in part: Many of the proposed tasks for the Webb telescope were planned and approved in the 1990s as the observatory was under initial development, said Klaus Pontoppidan, an a...

0
Q: Were K2-141b and WASP-63b selected as the first two exoplanet atmospheres for JWST to look at during its first year of observations? If so, why?

uhohIn The Observatory @Donald.McLean linked to Scientists will peer at first galaxies with James Webb telescope which says in part: The new telescope will augment science performed by Hubble, not necessarily replace it, (Nestor) Espinoza said. He is part of the James Webb team at the organization t...

Asked in Astronomy SE
 
@geoffc Starship payload to LEO is 100t. Its fuel mass is 1200t. Thus, to completely refill a starship on LEO, requires 12 tanker launches and not only 1.
 

« first day (2863 days earlier)      last day (66 days later) »