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
Quote from: jongoff on 03/11/2017 04:37 amAs 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.~JonCongrats 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)?
Quote from: AncientU on 03/12/2017 09:24 pmQuote from: jongoff on 03/11/2017 04:37 amAs 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.~JonCongrats 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 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.
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
Quote from: A_M_Swallow on 03/15/2017 06:57 pmThe 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.comI'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
Quote from: jongoff on 03/15/2017 10:15 pmQuote from: A_M_Swallow on 03/15/2017 06:57 pmThe 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.comI'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. ~JonUpper stages may have insufficient prox-ops but landers and capsules are very nimble and will have NDS. Reusable landers need to refuel.
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.
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.
Quote from: A_M_Swallow on 03/16/2017 09:21 amAn 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?.
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
Quote from: jongoff on 03/19/2017 03:57 amThe 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}~Jon10 µGs = 10 * 10-6 * 9.81 = approx 10-4 m/s2Using F = m aon a 50 tonne wet vehicleF = 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/aIMHO 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
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