Author Topic: Propellant Depots - General Discussion  (Read 233079 times)

Offline jongoff

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Re: Propellant Depots - General Discussion
« Reply #1020 on: 03/11/2017 04:37 AM »
As I mentioned in this other post and the blog article it links to (http://forum.nasaspaceflight.com/index.php?topic=22738.msg1652524#msg1652524), Altius was just awarded an SBIR Phase II to continue work on the cryogenic propellant coupler. We should have the contract started by some time in late April or early May. I'll post more details on the Altius thread when I have them.

~Jon

Offline AncientU

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Re: Propellant Depots - General Discussion
« Reply #1021 on: 03/12/2017 09:24 PM »
As I mentioned in this other post and the blog article it links to (http://forum.nasaspaceflight.com/index.php?topic=22738.msg1652524#msg1652524), Altius was just awarded an SBIR Phase II to continue work on the cryogenic propellant coupler. We should have the contract started by some time in late April or early May. I'll post more details on the Altius thread when I have them.

~Jon

Congrats Jon!

Is the idea to make universal couplers following the docking adaptor concept?  Fuel specific or general cryogens?  What types of flow rates/volume transfer rates are targeted (large craft or small)?
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Offline jongoff

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Re: Propellant Depots - General Discussion
« Reply #1022 on: 03/15/2017 03:40 PM »
As I mentioned in this other post and the blog article it links to (http://forum.nasaspaceflight.com/index.php?topic=22738.msg1652524#msg1652524), Altius was just awarded an SBIR Phase II to continue work on the cryogenic propellant coupler. We should have the contract started by some time in late April or early May. I'll post more details on the Altius thread when I have them.

~Jon

Congrats Jon!

Is the idea to make universal couplers following the docking adaptor concept?  Fuel specific or general cryogens?  What types of flow rates/volume transfer rates are targeted (large craft or small)?

I'm not sure what you mean by your first question. But for the second question, the architecture we're developing should work for any cryogenic propellant (LOX, LH2, liquid methane, liquid propane, liquid helium, etc). And for the other question, the coupling should be scalable from smallsat launch vehicle application sizes all the way up to ACES, EUS, ITS, or New Glenn's upper stage. In Phase II we're focusing on something on the smaller end of that spectrum, but we could probably make this work for any flow rate realistically imaginable.

~Jon

Offline A_M_Swallow

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Re: Propellant Depots - General Discussion
« Reply #1023 on: 03/15/2017 06:57 PM »
As I mentioned in this other post and the blog article it links to (http://forum.nasaspaceflight.com/index.php?topic=22738.msg1652524#msg1652524), Altius was just awarded an SBIR Phase II to continue work on the cryogenic propellant coupler. We should have the contract started by some time in late April or early May. I'll post more details on the Altius thread when I have them.

~Jon

Congrats Jon!

Is the idea to make universal couplers following the docking adaptor concept?  Fuel specific or general cryogens?  What types of flow rates/volume transfer rates are targeted (large craft or small)?

I'm not sure what you mean by your first question. But for the second question, the architecture we're developing should work for any cryogenic propellant (LOX, LH2, liquid methane, liquid propane, liquid helium, etc). And for the other question, the coupling should be scalable from smallsat launch vehicle application sizes all the way up to ACES, EUS, ITS, or New Glenn's upper stage. In Phase II we're focusing on something on the smaller end of that spectrum, but we could probably make this work for any flow rate realistically imaginable.

~Jon

The NASA Docking System, which implements the International Docking System Standard (IDSS). The standard has a planned extension "... in future implementations will be able to transfer water, fuel, oxidizer and pressurant as well."

The IDSS is currently at Revision E October 2016. The appropriate pages are 3-38 and 3-59. Currently the actual size and shape of the connectors is undefined.
http://www.internationaldockingstandard.com

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Re: Propellant Depots - General Discussion
« Reply #1024 on: 03/15/2017 08:03 PM »
The IDSS is currently at Revision E October 2016. The appropriate pages are 3-38 and 3-59. Currently the actual size and shape of the connectors is undefined.
Relevant thread plug where proposed fluid and electrical coupling standard interface is being defined for satellites.
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Offline jongoff

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Re: Propellant Depots - General Discussion
« Reply #1025 on: 03/15/2017 10:15 PM »
The NASA Docking System, which implements the International Docking System Standard (IDSS). The standard has a planned extension "... in future implementations will be able to transfer water, fuel, oxidizer and pressurant as well."

The IDSS is currently at Revision E October 2016. The appropriate pages are 3-38 and 3-59. Currently the actual size and shape of the connectors is undefined.
http://www.internationaldockingstandard.com

I'm familiar with IDS/NDS, but it wasn't clear that was what he was asking. Yes, you could use this coupler with something like that. But that isn't the planned operational mode unless a customer wants it done that way. My notional approach would be to have a soft-capture using magnetic versions of our sticky boom, followed by a robotic connection. Trying to do a traditional docking operation requires more prox-ops capability than upper stages typically have.

~Jon

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Re: Propellant Depots - General Discussion
« Reply #1026 on: 03/16/2017 05:00 AM »
The NASA Docking System, which implements the International Docking System Standard (IDSS). The standard has a planned extension "... in future implementations will be able to transfer water, fuel, oxidizer and pressurant as well."

The IDSS is currently at Revision E October 2016. The appropriate pages are 3-38 and 3-59. Currently the actual size and shape of the connectors is undefined.
http://www.internationaldockingstandard.com

I'm familiar with IDS/NDS, but it wasn't clear that was what he was asking. Yes, you could use this coupler with something like that. But that isn't the planned operational mode unless a customer wants it done that way. My notional approach would be to have a soft-capture using magnetic versions of our sticky boom, followed by a robotic connection. Trying to do a traditional docking operation requires more prox-ops capability than upper stages typically have.

~Jon

Upper stages may have insufficient prox-ops but landers and capsules are very nimble and will have NDS. Reusable landers need to refuel.

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Re: Propellant Depots - General Discussion
« Reply #1027 on: 03/16/2017 09:21 AM »
Thinking about it a spacestation is likely to have both docking ports and arms.

Docking ports are expensive and heavy because they provide access for people and power. The extended version supplies a simple way of providing fuel, LOX and water to a lander.

An upper stage does not carry people (unlike the capsule) so saving mass getting the spacestation's arm to grab the stage would be a valid attachment system. There would have to be pipes to carry the propellant from the arm to the lander, possibly via fuel tanks.

Offline jongoff

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Re: Propellant Depots - General Discussion
« Reply #1028 on: 03/17/2017 02:18 PM »
The NASA Docking System, which implements the International Docking System Standard (IDSS). The standard has a planned extension "... in future implementations will be able to transfer water, fuel, oxidizer and pressurant as well."

The IDSS is currently at Revision E October 2016. The appropriate pages are 3-38 and 3-59. Currently the actual size and shape of the connectors is undefined.
http://www.internationaldockingstandard.com

I'm familiar with IDS/NDS, but it wasn't clear that was what he was asking. Yes, you could use this coupler with something like that. But that isn't the planned operational mode unless a customer wants it done that way. My notional approach would be to have a soft-capture using magnetic versions of our sticky boom, followed by a robotic connection. Trying to do a traditional docking operation requires more prox-ops capability than upper stages typically have.

~Jon

Upper stages may have insufficient prox-ops but landers and capsules are very nimble and will have NDS. Reusable landers need to refuel.

As I said, there's nothing to preclude using this coupler as part of an NDS. It's just a simple tube-in-tube design with some magic in the seal design. I just also think that unless you need to seal a large diameter pressure hatch (like you would for a capsule or a lander), that a hard docking ring isn't the right approach compared to a soft-dock approach. Fortunately the coupler can support either method quite easily.

~Jon

Offline jongoff

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Re: Propellant Depots - General Discussion
« Reply #1029 on: 03/17/2017 02:21 PM »
An upper stage does not carry people (unlike the capsule) so saving mass getting the spacestation's arm to grab the stage would be a valid attachment system. There would have to be pipes to carry the propellant from the arm to the lander, possibly via fuel tanks.

We're also talking about multiple much lighter weight arms than the station arms. Like was shown in the picture in my blog post:

http://www.altius-space.com/wp-content/uploads/2017/03/DistributedLaunchFauxArt.png

~Jon

Online oldAtlas_Eguy

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Re: Propellant Depots - General Discussion
« Reply #1030 on: 03/17/2017 02:33 PM »
What is really needed is a lightweight NDS that offers power and fluid transfers but has no people access ability. A reusable tug (re-purposed US) would need the structural docking offered by NDS to latch onto payloads and get them to other orbits. An interface to dock to the depot and the same to then dock to the payload would simplify the use of such a tug. Also if a vehicle that wants to refuel uses an NDS (with fluids transfer standard) then no arms are necessary on the depot unless they are needed to perform maintenance on the depot itself.

Standardize the interfaces. Simplyfy the system and methods/procedures. Use of an arm increases complexity, time, and cost of attaching to the depot. An automated docking is the lowest cost procedure wise.

Look at the system from the depot provider's point of view. Make the attachment and fueling of vehicles as automated/standard and simple as possible.

Put the requirement onto the users to comply with standards if they want the fuel. Also this simplifies the prop up-load deliveries such that they use the same docking mechanisms/ports. So that only one port type exists on the depot.

A BTW fluid transfers are halted during docking. So it is in everyone's interest if the depot is servicing multiple vehicles simultaneous (tanker and tugs/Upper Stages) that docking is done in the shortest amount of time. Arm capture and berthing is a very long process.

Offline jongoff

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Re: Propellant Depots - General Discussion
« Reply #1031 on: 03/17/2017 11:30 PM »
What is really needed is a lightweight NDS that offers power and fluid transfers but has no people access ability. A reusable tug (re-purposed US) would need the structural docking offered by NDS to latch onto payloads and get them to other orbits. An interface to dock to the depot and the same to then dock to the payload would simplify the use of such a tug. Also if a vehicle that wants to refuel uses an NDS (with fluids transfer standard) then no arms are necessary on the depot unless they are needed to perform maintenance on the depot itself.

Standardize the interfaces. Simplyfy the system and methods/procedures. Use of an arm increases complexity, time, and cost of attaching to the depot. An automated docking is the lowest cost procedure wise.

Look at the system from the depot provider's point of view. Make the attachment and fueling of vehicles as automated/standard and simple as possible.

Put the requirement onto the users to comply with standards if they want the fuel. Also this simplifies the prop up-load deliveries such that they use the same docking mechanisms/ports. So that only one port type exists on the depot

I'm just not sure an NDS-style connector, even without the pressure port, is the right way to do this. I think I could do a multi-Sticky Boom solution for less mass and complexity, especially on the receiving side.

On the receiving side, the DogTags (capture targets for the Electropermanent Magnetic Sticky Booms) we're developing weigh less than 100g each, and you could probably get away with 6 of them per vehicle for an upper stage. Even if you wanted to make them bigger to enable even sloppier capture connections, you're talking low single digit kg per captured vehicle, not 100s of kg for an NDS-style adapter sized for an ACES to ACES connection.

NDS requires precision prox-ops to get the two pieces together, while I'm trying to design Sticky Booms to handle an upper stage rendezvousing directly with another upper stage or with a depot. Ie something that can handle modest relative velocities and position mismatches, doesn't require stationkeeping, doesn't require formation flying, etc. I still need to do some work on sizing, but my guess is I can get 4 Sticky Booms in for less mass than a single NDS on the capturing side.

For cargo or spacecraft that need to be tugged around, adding three DogTags on the back would still likely be <1kg of added mass even for a big payload.

I know NDS is what people are used to, I just don't think it's the end-all-be-all of connecting things in space. Especially if you don't need to seal a large diameter pressure-tight connection for passing people back and forth. That's what NDS shines for. Not for soft capturing upper stages or payloads for cargo or propellant transfer.

Quote
A BTW fluid transfers are halted during docking. So it is in everyone's interest if the depot is servicing multiple vehicles simultaneous (tanker and tugs/Upper Stages) that docking is done in the shortest amount of time. Arm capture and berthing is a very long process.

With Canadarm maybe, but primarily because they have an irreplaceable arm that they don't trust to do the captures autonomously, so they have a human sticky flying the arm (as I understand it). There's no reason why you can't have capture operations be much quicker with proper supervised autonomy. Once again, I don't think NDS is the answer *unless* you need a pressurized hatch that people can go through, in which case it's great.

~Jon
« Last Edit: 03/17/2017 11:31 PM by jongoff »

Offline TrevorMonty

Re: Propellant Depots - General Discussion
« Reply #1032 on: 03/18/2017 06:02 AM »
An upper stage does not carry people (unlike the capsule) so saving mass getting the spacestation's arm to grab the stage would be a valid attachment system. There would have to be pipes to carry the propellant from the arm to the lander, possibly via fuel tanks.

We're also talking about multiple much lighter weight arms than the station arms. Like was shown in the picture in my blog post:

http://www.altius-space.com/wp-content/uploads/2017/03/DistributedLaunchFauxArt.png

~Jon
Jon is transfer done under very small thrust to settle fluid? If so how much thrust in Gs and which stage provides thrust.

How do booms hold up to thrust?.

Offline jongoff

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Re: Propellant Depots - General Discussion
« Reply #1033 on: 03/19/2017 03:57 AM »
Jon is transfer done under very small thrust to settle fluid? If so how much thrust in Gs and which stage provides thrust.

The details will likely depend on the vehicles transfering propellants, but generally I think it would be better if both vehicles were providing settling thrust (as otherwise you'd create a torque). ULA found that very low thrust levels (IIRC 10s of µGs) was enough for propellant settling, so you're not talking a lot of thrust.

Quote
How do booms hold up to thrust?.

One nice thing about these booms is that they're extendable and rectractable. So after the initial soft capture, you can pull them in all or most of the way to make the connection very stiff in spite of being lightweight. Definitely robust enough to handle the minor forces due to settling thrusters.

~Jon

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Re: Propellant Depots - General Discussion
« Reply #1034 on: 03/19/2017 11:32 AM »

The details will likely depend on the vehicles transfering propellants, but generally I think it would be better if both vehicles were providing settling thrust (as otherwise you'd create a torque). ULA found that very low thrust levels (IIRC 10s of µGs) was enough for propellant settling, so you're not talking a lot of thrust.

{snip}
~Jon

10 µGs = 10 * 10-6 * 9.81 = approx 10-4 m/s2

Using F = m a
on a 50 tonne wet vehicle

F = 50,000 * 10-4 = 5 N (or 1.1 lbf)

There are several thrusters in the 5 N range. Normally aimed at station keeping for satellites. So cold thrusters, mono-propellants, ion thrusters and solar thermal thrusters are available. Since refuelling can take several hours the engineers may wish to use the same fuel as the main engines, the Morpheus lander had methane/LOX RCS thrusters in that thrust range.

If the settling thruster comes with an accurate accelerometer it can be used to measure the change in mass of the vehicle m = F/a

IMHO the FAA will want the equipment calibrated (see aircraft refuelling) and require allowance for propellant burnt and the mass of any people and cargo transferred.

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Re: Propellant Depots - General Discussion
« Reply #1035 on: 03/21/2017 03:32 AM »

The details will likely depend on the vehicles transfering propellants, but generally I think it would be better if both vehicles were providing settling thrust (as otherwise you'd create a torque). ULA found that very low thrust levels (IIRC 10s of µGs) was enough for propellant settling, so you're not talking a lot of thrust.

{snip}
~Jon

10 µGs = 10 * 10-6 * 9.81 = approx 10-4 m/s2

Using F = m a
on a 50 tonne wet vehicle

F = 50,000 * 10-4 = 5 N (or 1.1 lbf)

There are several thrusters in the 5 N range. Normally aimed at station keeping for satellites. So cold thrusters, mono-propellants, ion thrusters and solar thermal thrusters are available. Since refuelling can take several hours the engineers may wish to use the same fuel as the main engines, the Morpheus lander had methane/LOX RCS thrusters in that thrust range.

If the settling thruster comes with an accurate accelerometer it can be used to measure the change in mass of the vehicle m = F/a

IMHO the FAA will want the equipment calibrated (see aircraft refuelling) and require allowance for propellant burnt and the mass of any people and cargo transferred.

For ACES the IVF GOX/GH2 thrusters are more than adequate for settling.

~Jon

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Re: Propellant Depots - General Discussion
« Reply #1036 on: 03/21/2017 04:22 AM »

For ACES the IVF GOX/GH2 thrusters are more than adequate for settling.

~Jon

Good.

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Re: Propellant Depots - General Discussion
« Reply #1037 on: 03/29/2017 05:39 PM »
I'll be doing a FISO telecon presentation today (3pm EDT) about some aspects of using propellant depots. I'll upload a copy of my presentation once I'm done if people are interested.

~Jon

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Re: Propellant Depots - General Discussion
« Reply #1038 on: 03/29/2017 09:05 PM »
I'll be doing a FISO telecon presentation today (3pm EDT) about some aspects of using propellant depots. I'll upload a copy of my presentation once I'm done if people are interested.

~Jon

The presentation went well. While direct links from Twitter don't appear to work, they do seem to work here on the NSF forum.

Presentation: http://spirit.as.utexas.edu/%7Efiso/telecon/Goff_3-29-17/Goff_3-29-17.pptx

The audio isn't up yet, but I'll post a link later when it's up.

Edit: Here's the audio to go with the presentation: http://spirit.as.utexas.edu/%7Efiso/telecon/Goff_3-29-17/Goff.mp3

~Jon
« Last Edit: 03/30/2017 03:50 AM by jongoff »

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