Jump to content

[New] Space Launch System / Orion Discussion Thread


Recommended Posts

Not certain, but it does appear CAPSTONE will operate as a relay.  I can't see any other reasonable interpretation of this paragraph.  There is surely a better source than Gizmodo with better reporting but this came up quick in a search. (from last paragraph)

"The next step for CAPSTONE, aside from the final clean-up maneuvers, is to test the CAPS software developed by Advanced Space. CAPS should make it possible for spacecraft to communicate with other spacecraft, reducing the need for ground stations to mediate these sessions. This will become increasingly important as more satellites are sent to the Moon in the coming years, and as NASA and its international partners work to build a sustainable crewed presence in the lunar environment."

https://gizmodo.com/capstone-reaches-orbit-around-moon-1849779300

Link to comment
Share on other sites

Deceased Apollo LM engineers must be rolling in their graves.

They could at least say capsule. Instead they have gone from “spacecraft” to “spacecraft designed for humans”, which ironically makes it explicitly include the LM ascent stage. At least “spacecraft” could be passed off as a categorization mistake!

This is the equivalent of me being an aviation engineer, building the world’s highest flying crewed aircraft, and saying the people in it “will fly higher than any human ever before”.

I’ll add it either means NASA PR people and the engineers who go along with this don’t know much about Apollo, or they are deliberately ignoring facts for PR purposes.

Makes sense given SLS’ justification (and to a certain extent Orion’s too) is based on ignoring the existence of Commercial Crew vehicles and Starship.

Link to comment
Share on other sites

12 hours ago, SunlitZelkova said:

Deceased Apollo LM engineers must be rolling in their graves.

They could at least say capsule. Instead they have gone from “spacecraft” to “spacecraft designed for humans”, which ironically makes it explicitly include the LM ascent stage. At least “spacecraft” could be passed off as a categorization mistake!

This is the equivalent of me being an aviation engineer, building the world’s highest flying crewed aircraft, and saying the people in it “will fly higher than any human ever before”.

The terminology here has all sorts of fun technicalities. The farthest distance traveled by any craft designed for humans might be a certain Tesla Roadster, although it wasn't designed for humans in the regime of space.

But in either case, I guess Snoopy, the Lunar Landing Module tested during Apollo 10 and subsequently ejected into a heliocentric orbit, comfortably beats Orion on every relevant metric.

Link to comment
Share on other sites

4 hours ago, Codraroll said:

The terminology here has all sorts of fun technicalities. The farthest distance traveled by any craft designed for humans might be a certain Tesla Roadster, although it wasn't designed for humans in the regime of space.

But in either case, I guess Snoopy, the Lunar Landing Module tested during Apollo 10 and subsequently ejected into a heliocentric orbit, comfortably beats Orion on every relevant metric.

However, Snoopy was not intended to carry humans to the distance it achieved, whereas Orion was. 

Link to comment
Share on other sites

58 minutes ago, cubinator said:
5 hours ago, Codraroll said:

The terminology here has all sorts of fun technicalities. The farthest distance traveled by any craft designed for humans might be a certain Tesla Roadster, although it wasn't designed for humans in the regime of space.

But in either case, I guess Snoopy, the Lunar Landing Module tested during Apollo 10 and subsequently ejected into a heliocentric orbit, comfortably beats Orion on every relevant metric.

However, Snoopy was not intended to carry humans to the distance it achieved, whereas Orion was. 

"Orion will be entering a distant retrograde orbit beyond the moon, breaking the record set by Apollo 13 for the [greatest distance from Earth achieved] by a [pressurized spacecraft with sufficient internal volume to hold multiple humans and an outer mold line suitable for controlled atmospheric re-entry] at 248,655 miles from Earth."

Although I wonder if even that is true. It seems to me that there's a pretty substantial difference between the distance to the Moon at perigee and at apogee, which might need to be taken into consideration.

At perigee, the moon can be as close to Earth as 356,400 km (221,500 miles), while at apogee it can be as far as 406,700 km (252,700 miles).

So if any of the Apollo missions took place close to apogee, their command module parking orbits may well have been farther from Earth's surface than Orion.

It's also unclear whether the number provided by NASA above is actually a measurement of distance from Earth's surface or if it is based on distance from the center of the Earth.

Edited by sevenperforce
no one knows
Link to comment
Share on other sites

Since it’s unmanned, I don’t think it should qualify for any record, it’s just an elaborate probe with extra shiny.    Snoopy, however, was manned at some point in its mission, and should count for something.    Once Artemis starts carrying meaty payloads, then I’ll start paying attention to records.  

Link to comment
Share on other sites

1 hour ago, sevenperforce said:

It seems to me that there's a pretty substantial difference between the distance to the Moon at perigee and at apogee, which might need to be taken into consideration.

At perigee, the moon can be as close to Earth as 356,400 km (221,500 miles), while at apogee it can be as far as 406,700 km (252,700 miles).

So if any of the Apollo missions took place close to apogee, their command module parking orbits may well have been farther from Earth's surface than Orion.

It's also unclear whether the number provided by NASA above is actually a measurement of distance from Earth's surface or if it is based on distance from the center of the Earth.

And of course there's a website that lists all of this. The moon was at apogee two days before Orion launched, on November 14, with a distance (center to center) of 404,924 km. It will be at perigee this Saturday, November 26, with a distance of 362,826 km, and it will be back at apogee on December 12, with a distance of 405,869 km.

Orion will be Distant Retrograde Orbit from November 25-30, so its "greatest distance" will be achieved with the moon closest to Earth, as shown by this mission track in the reference frame rotating with the moon (source is NASA):

Animation_of_Artemis_I_around_Earth_-_Fr

comoving.png

Here blue is the Earth and the green dot and line show the moon's location relative to Earth, moving between apogee and perigee. Orion only completes one half-orbit in DRO before performing the burn to take it back down to the moon, and NASA states here that the DRO is about 70,000 km away from the moon. So at its greatest distance from Earth, it will be 432,826 km from the center of the Earth or 426,448 km in absolute altitude.

Apollo 13's record was 400,171 km in absolute altitude, set not because the distance from the moon was particularly great (although it was about 100 km greater than in past missions) but because the moon was near apogee during that flyby.

So it would appear that Orion WILL break Apollo 13's record, not because of the Earth-Moon distance, but because of its greater distance from the moon.

Link to comment
Share on other sites

4 hours ago, sevenperforce said:

So it would appear that Orion WILL break Apollo 13's record, not because of the Earth-Moon distance, but because of its greater distance from the moon.

Still doesn’t beat Voyager.    Until Artemis has a meat payload, they’re the same thing.   :) 
 

And I did not appreciate how goofy that orbit is.    

Link to comment
Share on other sites

1 hour ago, Gargamel said:

Still doesn’t beat Voyager.    Until Artemis has a meat payload, they’re the same thing.   :) 

And I did not appreciate how goofy that orbit is.    

Then you'll hate how it looks from Earth's inertial reference frame.

Animation_of_Artemis_I_around_Earth.gif

Funny that it makes a retrograde re-entry to Earth. I wonder why.

Link to comment
Share on other sites

2 hours ago, sevenperforce said:

Then you'll hate how it looks from Earth's inertial reference frame.

Animation_of_Artemis_I_around_Earth.gif

Funny that it makes a retrograde re-entry to Earth. I wonder why.

Those kinds of plots are crazy.  Like you wouldn't guess that the paths look like that.  First time I saw something like it was a representation of asteroid belt and the Trojans and Greeks. Kind of eye opening. 

If you find an answer to why the retrograde, let us know! 

Link to comment
Share on other sites

2 hours ago, sevenperforce said:

Then you'll hate how it looks from Earth's inertial reference frame.

Animation_of_Artemis_I_around_Earth.gif

Funny that it makes a retrograde re-entry to Earth. I wonder why.

Is this relative to surface rotation, or is the 24-hour loop not considered?

Also, gotta say, that eccentric orbit drop from the sky looks a little extreme for reentry of a human-rated vehicle, but maybe it does relatively softer aerobraking passes like Apollo did?.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...