Dynetics lunar lander

[FutureSpaceTourist]

Think it’s about time we had a specific thread for Dynetics’ lander

Feel free to cross-post any key info from other threads

[FutureSpaceTourist]

https://twitter.com/dynetics/status/1257370125008883712

While we’re adding to our resume, it may be time to add to yours. We’re hiring for several positions that will help craft the Human Landing System! Visit our careers page to apply >> https://www.dynetics.com/careers/

[ZChris13]

Thank you, FutureSpaceTourist, I was looking all over for this thread. Didn't realize that it just didn't exist yet. I find the Dynetics proposal really interesting, although that my just be because I'm quite fond of drop tanks.
TrevorMonty has some number crunching that I found enlightening.

So the Dynetics lander requires SLS? I don't see how that thing could self-assemble in lunar orbit...

I have been wondering about this. The press release specifically refers to possibly launching on Vulcan and ULA is a subcontractor. Also, re-usability would require the ability to send new drop tanks to lunar orbit as well as refueling the attached tanks.

Long life Centuar can deliver tanks direct to Gateway. A robotic arm is needed to transfer tanks.
No mention of fuel, but if methane then assume ISP of 360 and 40t wet mass (SLS 1B TLI).
TLI  to surface is 3km/s so lands with 17t.
2.5km/s to station so burns  9t  to arrive as 8t empty.

Needs 31t of drop tanks/fuel for new mission. Thats 4 Vulcan heavy resupply missions, so about $600m which is lot cheaper than a SLS 1B.

Edit: For Vulcan launch of lander, they only use 3 tanks, that would keep it under Vulcan 35t LEO rating and also shorten it for fairing. Only need a enough DV to reach Gateway, so 3 tanks is more than enough.

Drop tanks could also contain He for pressurization, giving them complete fuel system. Connections should be 2 fuel (fuel +oxidizer), 1 electrical and mechanical mounts.

I had some thoughts on this number-crunch as well, which may or may not be actually relevant.

If they use methane, then Starship could deliver 250+ tons of drop tanks and fuel directly to the gateway (Just like Centaur! The difference between upper stage and spacecraft is getting smaller. It's a good system.) That should be good for ~8 round trips from NRHO to the surface. I think this is a better deal than trying to refuel a Starship for this purpose, especially with CLPS delivered supplies waiting on the surface.

And a final question: what's the dv split on those tanks? Will they be left lying around in lunar orbit or will they be crasher tanks?

[tbellman]

Will they [the tanks] be left lying around in lunar orbit or will they be crasher tanks?

In the video, it looks like they are dropped while descending.  Note how they are falling downwards (at 0:45).  They would then crash into the lunar surface (hopefully some safe distance away from any pre-delivered cargo ).

[TrevorMonty]

Will they [the tanks] be left lying around in lunar orbit or will they be crasher tanks?

In the video, it looks like they are dropped while descending.  Note how they are falling downwards (at 0:45).  They would then crash into the lunar surface (hopefully some safe distance away from any pre-delivered cargo ).

They also have He pressure tanks on outside. May actually be storable fuel not Methane and LOX. Do they replaced refuel inner tanks.

[pochimax]

Maybe MON-25, like in Astrobotic's Peregrine?

https://www.dynetics.com/newsroom/news/2018/astrobotic-selects-dynetics-as-propulsion-provider-for-the-peregrine-lunar-lander

Dynetics will integrate Peregrine's main engines and attitude control thrusters, controller electronics, tanks, and feed system into a single system that performs all propulsive maneuvers from cruise to soft landing on the Moon.  The Dynetics-led system will feature a propellant with a next-generation oxidizer called MON-25, which has a higher nitric oxide content to provide better thermal capability to operate more efficiently in deep space environments than previous oxidizers. Dynetics will procure the engines from Simi Valley, CA-based Frontier Aerospace, which is under contract with NASA to qualify the engines for lunar missions. 

https://www.nasa.gov/centers/marshall/news/releases/2020/moon-thrusters-withstand-over-60-hot-fire-tests.html

I don' t know, buy seeing how Peregrine looks like... It might have a lot of things in common. (8x Peregrine engines?)

https://twitter.com/astrobotic/status/1233059171446247426

https://twitter.com/JimBridenstine/status/1255902520251121664

[TrevorMonty]

Maybe MON-25, like in Astrobotic's Peregrine?

https://www.dynetics.com/newsroom/news/2018/astrobotic-selects-dynetics-as-propulsion-provider-for-the-peregrine-lunar-lander

Dynetics will integrate Peregrine's main engines and attitude control thrusters, controller electronics, tanks, and feed system into a single system that performs all propulsive maneuvers from cruise to soft landing on the Moon.  The Dynetics-led system will feature a propellant with a next-generation oxidizer called MON-25, which has a higher nitric oxide content to provide better thermal capability to operate more efficiently in deep space environments than previous oxidizers. Dynetics will procure the engines from Simi Valley, CA-based Frontier Aerospace, which is under contract with NASA to qualify the engines for lunar missions. 

https://www.nasa.gov/centers/marshall/news/releases/2020/moon-thrusters-withstand-over-60-hot-fire-tests.html

I don' t know, buy seeing how Peregrine looks like... It might have a lot of things in common. (8x Peregrine engines?)

https://twitter.com/astrobotic/status/1233059171446247426

https://twitter.com/JimBridenstine/status/1255902520251121664

There seems to be some partnership with Astrobotics as they are also selling payload capacity on Dynetics lander.

http://www.parabolicarc.com/2020/05/04/astrobotic-to-develop-new-commercial-payload-service-for-nasas-human-landing-system/

With Astrobotics using same engine then it should have done 1 or 2 landings before Dynetics mission. They may also be sharing landing guidance systems.

If this case Astrobotics missions would retire lot of Dynetics landers technology risks.

The two companies and landers complement each other so it makes sense to share technology.

A LEO demostration of refuelling or drop tank replacements would also be good idea, especially if commercial LV launching first lander.

[Nathan2go]

I wonder if those solar panels rotate to track the sun?  There are polar landing sites that have sunshine for many months at a time; the catch is that the sun stays near the horizon, and rotates around over the course of a month.
---
Also, I'm betting the descent drop tanks have extra capacity, so that on subsequent flights, they can be used to refuel the ascent tanks.  That way, replacing two drop tanks at Gateway makes the lander ready to go again. 

[Rocket Science]

Most sensible of the three proposals with the least risk...

[Eric Hedman]

One thing puzzles me on this design and the spherical drop tanks and the pair of spherical tanks used for ascent.  Is one tank out of each pair for fuel and the other for oxidizer?  Does this require lines feeding across from one side of the vehicle to the other for supplying engines on the other side?  Or does each spherical tank have an internal bulkhead separating fuel from oxidizer so there would be no need for complex plumbing crossing from one side of the vehicle to the other?   

[Steven Pietrobon]

Maybe MON-25, like in Astrobotic's Peregrine?

PSLV uses MON-3 for the fourth stage, which is 3% nitric oxide (NO) and 97% N2O4. MON-25 is 25% nitric oxide and 75% N2O4.

https://en.wikipedia.org/wiki/Mixed_oxides_of_nitrogen

One thing puzzles me on this design and the spherical drop tanks and the pair of spherical tanks used for ascent.  Is one tank out of each pair for fuel and the other for oxidizer?

I don't believe so since the oxidiser to fuel mass ratio is around 2:1. I believe each tank contains both fuel and oxidiser separated by a common bulkhead.

[pochimax]

With Astrobotics using same engine [...]

I have just checked astrobotic' s Peregrine lander user guide, and it says 5 engines, so I suppose now it is not the same engine. 

http://astrobotic.com/payload-user-guide

Astrobotic is utilizing a propulsion system integrator to assemble the propulsion system and incorporate it with Peregrine’s structure. The system features five main engines and twelve Attitude and Control System (ACS) engines powered by a hypergolic bipropellant, which does not require ignition as the fuel and oxidizer combust on contact. A proven hydrazine derivative, Mono-Methyl-Hydrazine (MMH), serves as the fuel. The oxidizer is a solution of nitric oxide in dinitrogen tetroxide/nitrogen dioxide, 25% Mixed Oxides of Nitrogen (MON-25). Two tanks each of the fuel and oxidizer are spaced evenly about the craft with a fifth tank for the Helium pressurant in the center. Peregrine’s main engines, located within the cone, are used for all major maneuvers. The ACS thrusters, grouped in clusters of three and placed about the lander to ensure control with six degrees of freedom, maintain spacecraft orientation throughout the mission.

[TrevorMonty]

Maybe MON-25, like in Astrobotic's Peregrine?

PSLV uses MON-3 for the fourth stage, which is 3% nitric oxide (NO) and 97% N2O4. MON-25 is 25% nitric oxide and 75% N2O4.

https://en.wikipedia.org/wiki/Mixed_oxides_of_nitrogen

One thing puzzles me on this design and the spherical drop tanks and the pair of spherical tanks used for ascent.  Is one tank out of each pair for fuel and the other for oxidizer?

I don't believe so since the oxidiser to fuel mass ratio is around 2:1. I believe each tank contains both fuel and oxidiser separated by a common bulkhead.

There are two small tanks on each drop tank, my guess pressurization He, one for fuel and one for oxidizer.

[mike robel]

Well, that one looks like it can succeed.  I like the horizontal oriented based landing rather than the vertical ones.  Those are a long way down.  Less than 4 years to the deadline.

[yg1968]

See the post below.

Here is a link to the Dynetics Moon lander thread for which SNC is an important subcontractor:

https://forum.nasaspaceflight.com/index.php?topic=50843.0

https://twitter.com/SierraNevCorp/status/1255920265931960321

https://twitter.com/SierraNevCorp/status/1255999684214247429

SNC is proud to announce we’ve been chosen to provide Crewed Systems Services to Dynetics for NASA’s Human Landing System for the #Artemis mission to the moon. The module we build will be the living space that transports & houses crew in the journey to & from the lunar surface.

Our human spaceflight expertise developed through NASA’s CRS-2 & NextSTEP-2/Gateway programs gives us the expert knowledge needed to develop the Crewed Systems Services for Dynetics & NASA’s Human Landing System for the #Artemis mission to the moon.

https://www.sncorp.com/press-releases/snc-nasa-artemis-hls/

[GWH]

Gotta say I'm both highly entertained and puzzled by the name for this vehicle: ALPACA

[DreamyPickle]

Sierra Lobo will support this competition by leveraging 25 years of demonstrated expertise in developing the cryogenic propellant systems. These cryogenic propellant systems are like the “gasoline for a car” needed to support the rocket propulsion systems to maneuver the HLS to and from the moon’s surface. The HLS will be launched on top of a heavy launch vehicle and released around the vicinity of the moon. The “gas,” which was fueled on the earth, needs to be stored for a significant time prior to Human Lander Operations.  This is a significant challenge for cryogenics, which will naturally boil away on earth and in transit to the moon, its final destination, leaving a potentially empty gas tank when it’s needed to fire the rockets, if the system is not designed properly.

This indicates the lander is cryogenic. No mention of hydrogen though.

[TrevorMonty]

Sierra Lobo will support this competition by leveraging 25 years of demonstrated expertise in developing the cryogenic propellant systems. These cryogenic propellant systems are like the “gasoline for a car” needed to support the rocket propulsion systems to maneuver the HLS to and from the moon’s surface. The HLS will be launched on top of a heavy launch vehicle and released around the vicinity of the moon. The “gas,” which was fueled on the earth, needs to be stored for a significant time prior to Human Lander Operations.  This is a significant challenge for cryogenics, which will naturally boil away on earth and in transit to the moon, its final destination, leaving a potentially empty gas tank when it’s needed to fire the rockets, if the system is not designed properly.

This indicates the lander is cryogenic. No mention of hydrogen though.

Methane and LOX is most likely. There other options eg propane.

[Nathan2go]

[...]

This indicates the lander is cryogenic. No mention of hydrogen though.

Methane and LOX is most likely. There other options eg propane.

That makes the Dynetics offering more attractive, and has positive implications for the missions.  Not just compatibility with ISRU Lunar O2 or refilling from a Starship tanker, but also it is more suited to landing in a permanently shadowed crater, in search of ice.  Hypergolic propellants like hydrazine/N2O4 have to be kept warm to prevent freezing.

Note that Starship and Vulcan already have methane available on the launch pad, but SLS does not.  Propane however, is room temp storable (and freeze-resistant, down to nearly LOX temperatures), so it could be loaded prior to stacking on the vehicle, I guess.

Also, the tanks will need several different sets of vent values: 1 set for when it's on its side on the launcher, a 2nd set for on it's feet on the Moon, and a 3rd set for spin-ullaging at the Gateway?

I will be curious to see whether those heavy O2 tanks will be launched empty, and filled from the upper stage tanks after engine cut-off.  Otherwise, there will be a lot of structural mass holding up those tanks in the 2.5-3g launch environment.

Wait, this photo suggests that there is a strongback that is not part of the lander which provides tank support during launch?

[DreamyPickle]

Astrobotic has two landers on it's site: Peregrine with 5 small engines burning MON-25/MMH fuel and Griffin which is considerably larger and has a single larger central engine for which the only information listed is "300 ISP".

The Dynetics lander is probably be using the same engine as Griffin (just 8x).