incredible accuracy
"when the floating capsule will be 79.2 miles from the Moon's surface"
0.2 of a mile is 352 yards (≈322 m). Especially as a prediction, that's pretty fine resolution in the context of the lunar surface.
NASA's Orion capsule, designed to send the next crew of astronauts to the Moon, is heading back to Earth after spending some time in a distant retrograde orbit above the satellite's surface. The spacecraft fired its main engine on December 1 at 1553 CST (2153 UTC) for one minute and 45 seconds, changing its velocity by about …
"changing its velocity by about 454 feet per second,"
Sounds like the numbers got converted from metres. That would have been 135 m/s.
Those oddly precise numbers usually have that kind of origin, the writer just converting numbers and not thinking about the precision of the measurement converted from. You see that all the time.
When woodworking I mostly mark directly from the related parts (so I do not have to measure). Thus converting 4" to 10cm, or 1/2 " to 12mm works. Those numbers were not precise enough to care about exact conversions in the beginning. For any fitting of parts:don't measure. Mark directly.
4) a song by The Cure from the album 'Three Imaginary Boys"
== Bring us Dabbsy back! ==
> I believe that the navigation is done in nautical miles
Actually "space miles", of which the exact definition is only known by a retired engineer currently residing in some unspecified monastery in Tibet...
Why use clearly defined scientific units when you can use whatever takes your fancy, ideally without telling anybody about it? Freedom, man!
"Orion carries a trusty bit of equipment leftover from NASA's Space Shuttle era, its main engine, capable of providing 6,000 pounds (over 2,721 kilograms) of thrust "
Other sources suggest that the Space Shuttle's main engine provided as much as 470,000 pounds of thrust. One document does mention the "Orbital Maneuvering System Engines" producing 6,000 pounds of thrust.
So I've been a "space nut" for 55 years and the NASA coverage has been worse than watching paint dry. For engine firings, you don't even see the engines. There's maybe a puff of vapor from somewhere and some jiggling. They barely explain what you're seeing - "is that round thing the Earth? The Moon? Vulcan? a Death Star?"
They don't explain the mysterious bouncing of the ship between configurations is when you have telemetry (the real config) and don't have telemetry (some sort of stupid default, instead of keeping the last known values)
The trajectory explanation stuff is so dumbed down, even I don't recognize it.
They don't explain or even have a labeled graphic of what the pieces-parts-bits on the spacecraft are.
Then there's about every 15 minutes an announcement how this will support the landing of the first woman and the first person of color on the moon. Which is fine, but it does not need to be repeated every 15 minutes, thank you very much.
This is not how you win taxpayer funding.
NASA used to have a budget for education but it got cancelled. The problem with letting people go off script in a NASA broadcast is they may say something educational like Orion already did entry/descent/landing in 2014 and SLS was originally supposed to launch in 2017.
They're being really stupid with the broadcasts though.
Orion has a pile of cameras transmitting live video, yet they barely used then in the stream, instead they had an automated sequence showing a brief blip from some of them before jumping to a static logo graphic for around 90% of the time.
Just stream the cameras with an overlay of some telemetry.
Bandwidth becomes a bit of a problem with a craft that far from Earth. Remember that all of the fantastic footage from the Apollo flights was recorded on 16 mm film that had to be bright back and developed after the fact. The video footage beamed back from the lunar EVAs was either a) not very fantastic (in terms of resolution), or b) transmitted from a collapsible high-gain antenna that was too large to bolt to the side of the lunar lander and required manual setup by the crew.
Remember, when watching their excellent YouTube videos and their live streams, that NASASpaceFlight.com is a fan site, nothing to do with the National Aeronautics and Space Administration. That's why NASASpaceFlight's presenters can say what they like instead of sticking to a PR department script
“For engine firings, you don't even see the engines. There's maybe a puff of vapor from somewhere and some jiggling.”
To be fair, it’s the vacuum of space. Rocket firings aren’t the big Hollywood bursts of flame, they’re monomethylhydrazine reactions.
Waste of money, as most of it is not re-usable. The idea is great, and its great to see that after all these years, NASA is planning to send astronauts back to the moon, hopefully establishing a permanent base. But to cut costs, the main stage and boosters have to be re-usable. Space X has already proven that with Falcon 9. Cant wait until they prove it with Starship as well.
A lot of the bits have been recycled, loads of second hand shuttle parts, just this is their last use - rocket motors have a finite life and it's not a lot of firings.
To make something as large as the SLS return to the ground would require a lot more testing than SpaceX and it took them 20 failures before they got one to work and a few more crashes to refine it. Just imagine what people (such as yourself) would have said if NASA had pointlessly crashed at least 20 SLS stacks trying to get one to land. It would make no economic sense unless they were planning to launch hundreds of SLS stacks which was never the plan - the current plan is for 5 launches so wasting 20+ rockets just to try to save 5 rockets would be a insane waste of money.