totm dec 2023 Artemis Discussion Thread

[wumpus]

33 minutes ago, tater said:

LOL (relevant to all the companies, and pretty much all of them have some skin in the Artemis game, so here seems like a good place to put it):

 

Randal Monroe's inspiration for this comic?  [hint: if you expand it, it lists payloads of orbital rockets by horsepower.  That is, how many horses can be delivered to LEO.]

https://xkcd.com/1461/   [includes a much larger and readable image].

[Nightside]

1 hour ago, tater said:

LOL (relevant to all the companies, and pretty much all of them have some skin in the Artemis game, so here seems like a good place to put it):

 

So, "it works in KSP" is like TRL :3.5?

[RCgothic]

Am I missing something? $25k per lb is $55k per kg.

A reusable falcon nine costs around $50m, so let's be completely optimistic and say a rock-gathering return spacecraft can be done for $50m - $100m total.

To turn a profit on that you need to return around 2000kg of rock. F9(r)'s mass to TLI is ~3300kg. That's not returning 2000t of rock.

Falcon heavy expendable can send about 20t to TLI, but certainly costs at least $250m inc rock gathering spacecraft. Needs to return over 4.5t of rocks. That's still not happening.

Is NASA going to pay for the mission as well as the returned cargo?!?

[StrandedonEarth]

7 minutes ago, RCgothic said:

Am I missing something? $25k per lb is $55k per kg.

A reusable falcon nine costs around $50m, so let's be completely optimistic and say a rock-gathering return spacecraft can be done for $50m - $100m total.

To turn a profit on that you need to return around 2000kg of rock. F9(r)'s mass to TLI is ~3300kg. That's not returning 2000t of rock.

Falcon heavy expendable can send about 20t to TLI, but certainly costs at least $250m inc rock gathering spacecraft. Needs to return over 4.5t of rocks. That's still not happening.

Is NASA going to pay for the mission as well as the returned cargo?!?

IIRC the cash is paid when the samples are “handed off” to NASA control (a sample return craft). The samples don’t need to be returned to Earth to get paid. 

[RCgothic]

So the brief is more like:

"Design a robot deployable from an HLS lander and we'll pay $55k/kg returned to the lander."?

[Nightside]

39 minutes ago, RCgothic said:

Am I missing something? $25k per lb is $55k per kg.

A reusable falcon nine costs around $50m, so let's be completely optimistic and say a rock-gathering return spacecraft can be done for $50m - $100m total.

To turn a profit on that you need to return around 2000kg of rock. F9(r)'s mass to TLI is ~3300kg. That's not returning 2000t of rock.

Falcon heavy expendable can send about 20t to TLI, but certainly costs at least $250m inc rock gathering spacecraft. Needs to return over 4.5t of rocks. That's still not happening.

Is NASA going to pay for the mission as well as the returned cargo?!?

Moon pounds or earth pounds?

[RealKerbal3x]

1 minute ago, Nightside said:

Moon pounds or earth pounds?

Presumably pounds in terms of mass.

Kilograms are better anyway.

[Nightside]

7 minutes ago, RealKerbal3x said:

Presumably pounds in terms of mass.

Kilograms are better anyway.

Pounds-mass is only a thing if you know your reference gravity. This is the textbook example of not being able to assume g = 9.81 m/s² = 32.2 ft/s² everywhere.

Sloppy unit conversions kill space missions just as dead as faulty rockets.

[RealKerbal3x]

15 minutes ago, Nightside said:

Pounds-mass is only a thing if you know your reference gravity. This is the textbook example of not being able to assume g = 9.81 m/s² = 32.2 ft/s² everywhere.

Sloppy unit conversions kill space missions just as dead as faulty rockets.

In that case, we should just measure masses in Newtons instead. Gravity-independent units are a good thing.

[cubinator]

31 minutes ago, RealKerbal3x said:

In that case, we should just measure masses in Newtons instead. Gravity-independent units are a good thing.

Newtons are a unit of force, and thus weight. The kilogram is a gravity-independent unit of mass.

[sevenperforce]

11 minutes ago, cubinator said:

Newtons are a unit of force, and thus weight. The kilogram is a gravity-independent unit of mass.

I agree with @RealKerbal3x: we need to measure everything in gas mileage times pressure. 

[jinnantonix]

On 9/23/2020 at 10:55 PM, tater said:

SpaceX has, and Blue Origin will have the ability to launch test  articles at cost. Dynetics is using Vulcan, so any test is 3 Vulcan launches, making it pretty difficult.

Dynetics requires 2 Vulcan launches.  First one delivers the lander to LEO, second launch docks with and fuels the lander from the Centaur.  After each mission, the lander is refueled by 2 Vulcan launches, which also replace the drop tanks.

[tater]

9 minutes ago, jinnantonix said:

Dynetics requires 2 Vulcan launches.  First one delivers the lander to LEO, second launch docks with and fuels the lander from the Centaur.  After each mission, the lander is refueled by 2 Vulcan launches, which also replace the drop tanks.

Their press stated 3 launches, are there specifics on the flight profile?

[jinnantonix]

4 minutes ago, tater said:

Their press stated 3 launches, are there specifics on the flight profile?

I am going off the Dynetics HLS Wiki.  

[tater]

2 hours ago, jinnantonix said:

I am going off the Dynetics HLS Wiki.  

Sounds like unknown.

I have to imagine Centaur does the TLI.

The lander does LOI, then descent and landing (and transfer from NRHO to LLO). I assume the drop tanks are not refilled.

[kerbiloid]

8 hours ago, RealKerbal3x said:

In that case, we should just measure masses in Newtons instead.

Yes. In new-tons rather than old-tons.

[RealKerbal3x]

9 hours ago, cubinator said:

Newtons are a unit of force, and thus weight. The kilogram is a gravity-independent unit of mass.

 

9 hours ago, sevenperforce said:

I agree with @RealKerbal3x: we need to measure everything in gas mileage times pressure. 

My bad, that was a bit of a brain-fart 

[jinnantonix]

7 hours ago, tater said:

Sounds like unknown.

I have to imagine Centaur does the TLI.

The lander does LOI, then descent and landing (and transfer from NRHO to LLO). I assume the drop tanks are not refilled.

As I understand it, the second Centaur (launched on a naked Vulcan) docks in LEO and refuels the Dynetics lander and executes TLI.  The lander then does autonomous rendezvous with Gateway, and does the crewed lunar landing and ascent, drop tanks are ejected during lunar descent.

It is unclear but likely subsequent missions may require two launches:

1. Vulcan to LEO - Refueling craft.  
2. Naked launch with Centaur to boost above craft to TLI

...then delivery craft will rendezvous autonomously with Gateway, refuel the Dynetics lander at Gateway, and retro burn to lunar impact (disposal)

It is a good question whether drop tanks would be refitted.  I don't see that as feasible, way too complex and risky.  Is the lander (minus drop tanks) capable of a complete descent and ascent?

[tater]

Artemis II to have a Canadian astronaut.

[kerbiloid]

The first lunar hockey match?

[tater]

1 hour ago, kerbiloid said:

The first lunar hockey match?

CLPS has to first find a crater bottom covered with ice.

[kerbiloid]

3 minutes ago, tater said:

CLPS has to first find a crater bottom covered with ice.

Maybe this means that they have found right now....

[tater]

NSF story:

https://www.nasaspaceflight.com/2020/12/canada-to-become-second-nation-ever-to-send-people-to-the-moon/

"Canada to become second nation ever to send people to the Moon"

This headline implies Canada has something to do with the sending to me.

"NASA to send Canadian to the Moon" would be fine, obviously.

[kerbiloid]

Arm. 

[StrandedonEarth]

And all we had to do was give them a hand...