Lockheed Martin's "Jupiter" reusable space tug, CRS-2 bid

[HIP2BSQRE]

Please remember to keep this on topic.

[Robotbeat]

     Some of the designs I find interesting are the ones that use aerobraking for deceleration.  One of the OTV designs was a lifting body, which, in theory, could allow two additional capibilities that a disc shaped aerobrake lacks.

First, change of orbital inclination.  The self same capibility that allows a lifting body reentry vehicle to have a vastly extended crossrange versus a capsule, would also allow an aerobraking craft to adjust it's orbital inclination by several degrees without the use of fuel.  In surfer's terms, you'd be carving a wicked cut to go in a different direction, by using the atmosphere, and the craft's aerodynamic capibilities, to change the orbital inclination.

Second, if also equiped with landing gear, it would also allow the OTV, to be used as a lifeboat for a Earth return landing.  In theory, it could make a water landing, but this would be an exceptional risk.  Although the disk design would allow atmospheric entry, final deceleration could prove problimatic, even assuming a rocket fired final decelleration into the ocean.  Cold seawater and hot rocket nozzles don't really make for a too friendly combination.

"disc based" aerobraking can be lifting as well so would also be capable of these things.

[TrevorMonty]

The Jupiter tug would bring fuel depots a long with OTVs one step closer. The tug would allow payloads to be transferred to a OTV for delivery to BLEO. In case of depots, help dock the upper stage to depot or OTV for fuel transfer. Tug may even do the fuel transfer.

In case if Jupiter adding fuel transfer capabilities may just require a modified Exoliner with fuel transfer equipment.

[john smith 19]

"disc based" aerobraking can be lifting as well so would also be capable of these things.

There is no mention of aerobraking in LM's proposal.

[Elmar Moelzer]

Meh, I am not impressed. It seems like a step back compared to DC and Dragon. The whole BEO stuff sounds like marketing fluff to me. But maybe I am just feeling cynical today.

[MattMason]

Actually, you might want to recheck that.  the original idea for an otv was published before we even had space stations. Von Baun and a number of other Nasa types had been thinking about it back before they eve3n launched men into space.

The classical paradigm used the tug to lift payloads from the station to the Moon or a higher orbit, and used a Shuttle to get payloads to the station.

What Lockheed is proposing is to use a rocket to lift a payload to a parking orbit, using the rocket upper stage to stabilize the cargo payload, send a tug from the space station to rendezvous with the upper stage, and then return to the station with the tug.  Von Braun never considered that architecture.

Another approach Back in the Day was to have a "Shuttle" or Apollo type vehicle carry a Resource Module launched together with the crewed vehicle, and use the crewed vehicle to carry the cargo module to a station. That was considered and rejected for SkyLab.

As an aside, one of the benefits of operating a space station is that it provokes new thinking about operations in space. The more the station is used, the more operational alternates emerge from station requirements. Von Braun lived in a world where there was no station, so he could not see all the requirements.

And that's the key. Getting something into space now is, comparably, not a big problem.

It's manipulating what's been sent there to where you want it to be that's the trick, unless I missed something in my infantile skills in orbital mechanics.

And thrusters only go so far, unless all those robot arms on the Shuttle Orbiter and ISS are completely optional.

A number of us watch the SpaceX floating pad. It has its own power, but it needs guidance to move to the right positions with precision. (So does the cruise ship cam we use to watch the pad when it's moored.)

The Jupiter isn't so much as a spacecraft as it is a Elsbeth III or the Go Quest support ships that move the cargo to storage and transfer points. This action doesn't require the ISS but supports its mission, as it would others.

Several Jupiters could form a "dock" of its own, holding canisters for any number of needs that can be transferred elsewhere, sitting in a nice parking orbit.

As I might have said before, this is an infrastructure device. All the freight trucks in the world would be useless without cranes, tugs, forklifts, and this seems a very good start to defining space freight hardware. STS was supposed to work this way but was obviously far too expensive and compromised by design and politics.

[guckyfan]

I am not used to thinking in orbital parameters. But I do wonder. Jupiter will wait for the next mission in LEO, well below ISS. That means it can be anywhere in relation to the ISS. How does that affect launch windows or how does Jupiter get into the position it needs to be to first rendezvous with the launch vehicle then ISS. Will the time from launch to ISS docking be much longer than other vehicles?

[TrevorMonty]

Launch window would still be instantaneous as Jupiter is stationary relative to ISS. Where it meets the upper stage would have to be well clear of ISS eg 50km, to avoid any possible navigation errors by upper stage.

I would say Jupiter having abilities of a crane or forklift are its most more important features. Especially if these are totally automated, which may not be the case initially.

[Comga]

I am not used to thinking in orbital parameters. But I do wonder. Jupiter will wait for the next mission in LEO, well below ISS. That means it can be anywhere in relation to the ISS. How does that affect launch windows or how does Jupiter get into the position it needs to be to first rendezvous with the launch vehicle then ISS. Will the time from launch to ISS docking be much longer than other vehicles?

Jupiter can't "wait for the next mission in LEO, well below ISS" because if it does, it's orbit will precess at a rate different from that of the station's orbit.  It would then have to do a plane change to get back to rendezvous.  A small amount of this drift and the delta-V will quickly consume and then exceed, or at least waste, Jupiter's fuel load.The fact that it would in concept take longer to rendezvous is the least of the issues.

Jupiter will have to stay in the same orbit as ISS, either leading or trailing, maintaining its altitude in synchronization with the ISS, despite their different ballistic coefficients.  It might be able to "sail" with its solar panels to do this without burning fuel, but it can't do it without active control.  It probably is a minor effect if it drifts around the orbit, because it will have to rephase in any case after it descends to pick up a new Exoliner. 

[Danderman]

In this regard, looking at the concept of operations of the proposed Russian OKA-T spacecraft is useful. OKA-T would be able to refuel from Zvezda, and fly near the ISS orbit while performing science.

[Nilof]

This video got posted on the LM CRS-2 website:



Watching it now..

Some key things worth mentioning from that video that don't seem to have made it into the discussion:

* the Exoliner was dimensioned to be capable of launching together with an Orion on an SLS block I stack.
* Used as a deep space hab, it is large enough to fit both ISS-derived exercising equipment and closed cycle life support.

That is a substantial improvement over the baseline Orion in terms of deep-space capabillity. You could actually do some serious deep space missions with that.

[guckyfan]

Jupiter can't "wait for the next mission in LEO, well below ISS" because if it does, it's orbit will precess at a rate different from that of the station's orbit.  It would then have to do a plane change to get back to rendezvous.  A small amount of this drift and the delta-V will quickly consume and then exceed, or at least waste, Jupiter's fuel load.The fact that it would in concept take longer to rendezvous is the least of the issues.

Jupiter will have to stay in the same orbit as ISS, either leading or trailing, maintaining its altitude in synchronization with the ISS, despite their different ballistic coefficients.  It might be able to "sail" with its solar panels to do this without burning fuel, but it can't do it without active control.  It probably is a minor effect if it drifts around the orbit, because it will have to rephase in any case after it descends to pick up a new Exoliner.

OK, makes sense. Thank you for the explanation.

It means that Jupiter will have to stay in the ISS orbit until the next Exoliner is launched.

[Elmar Moelzer]

Some key things worth mentioning from that video that don't seem to have made it into the discussion:

* the Exoliner was dimensioned to be capable of launching together with an Orion on an SLS block I stack.
* Used as a deep space hab, it is large enough to fit both ISS-derived exercising equipment and closed cycle life support.

That is a substantial improvement over the baseline Orion in terms of deep-space capabillity. You could actually do some serious deep space missions with that.

Wouldn't it need a lot more radiation protection (and probably other modifications) to be usable as a deep space habitat?

[Jimmy Murdok]

It's ironic, that in the stack between Orion + Jupiter there is a full ATV disassembled as Orion service module + Exoliner cargo container.

I'm concerned about EVA's, as the stack will need to be disassembled each time. Besides that, the solution is quite practical and realistic to do something interesting with SLS+Orion in the 2020's. I really hope NASA invests in this solution for CRS-2.

[ChrisWilson68]

Meh, I am not impressed. It seems like a step back compared to DC and Dragon. The whole BEO stuff sounds like marketing fluff to me. But maybe I am just feeling cynical today.

I don't think it's a step forward or backward compared to DC and Dragon.  It's a step to the side.

DC or Dragon is good for downmass.  Jupiter is good for bulk delivery of upmass, plus other operations such as constructing new stations and moving supplies other places such as lunar orbit.  They are complementary.

[Danderman]

For reference, here is an animation showing the CSI approach to ISS servicing, using intermodal containers, and an ISS-based tug. In the case of CSI, the tug was Progress, not Jupiter.

FYI only.

[the_other_Doug]

I'm concerned about EVA's, as the stack will need to be disassembled each time.

I'd put an EVA hatch in the Exoliner and also the suit servicing equipment, and use the Exoliner as your airlock in the pictured configuration.

[TrevorMonty]

I'm concerned about EVA's, as the stack will need to be disassembled each time.

I'd put an EVA hatch in the Exoliner and also the suit servicing equipment, and use the Exoliner as your airlock in the pictured configuration.

That is the plan for a EAM whether it is based on a Exoliner, Cygnus or something else.
In the article below Exoliner wasn't public knowledge hence preference for Cygnus. Nice to see some competition for this EAM, Cygnus has flight history, Exoliner has more room, either way Thales wins.

http://spacenews.com/4212765th-international-astronautical-congress-nasa-studying-habitation-module/

[Burninate]

Jupiter can't "wait for the next mission in LEO, well below ISS" because if it does, it's orbit will precess at a rate different from that of the station's orbit.  It would then have to do a plane change to get back to rendezvous.  A small amount of this drift and the delta-V will quickly consume and then exceed, or at least waste, Jupiter's fuel load.The fact that it would in concept take longer to rendezvous is the least of the issues.

Jupiter will have to stay in the same orbit as ISS, either leading or trailing, maintaining its altitude in synchronization with the ISS, despite their different ballistic coefficients.  It might be able to "sail" with its solar panels to do this without burning fuel, but it can't do it without active control.  It probably is a minor effect if it drifts around the orbit, because it will have to rephase in any case after it descends to pick up a new Exoliner.

OK, makes sense. Thank you for the explanation.

It means that Jupiter will have to stay in the ISS orbit until the next Exoliner is launched.

Doesn't make sense to me.

How does "Precession" apply to this?  1) It's not spinning, so you're not talking about polar precession, and 2) periapsis precession does not modify the orbital plane.  Periapsis precession is far too slow a process to move apoapsis above the orbit of the ISS and create a collision risk in a reasonable amount of time, and at this altitude atmospheric drag is far too high to permit it: the atmosphere circularizes objects quickly.

3) It can't wait below the ISS, stationary to the ISS, not because of precession but because something at 350km altitude circular will simply have a shorter orbital period than something at 360km altitude circular, so while it would stay in the same plane, phasing would drift rapidly.

But phasing does not cost a lot of fuel to defeat, if you're willing to wait a few orbits for things to sync up.  As these are cargo ships, we are willing to wait.

4) Maybe you're arguing that the atmospheric drag against a rotating atmosphere will start to rotate the orbital plane out somehow?  I find I can't estimate that easily, but I'm skeptical that could have a huge effect.

[belegor]

@Burninate:

http://en.wikipedia.org/wiki/Nodal_precession