LM's Proposed ISS Cargo Spacecraft: Jupiter & Exoliner

[VirtualCLD]

According to one article I saw in Spaceflight Now, Lockheed Martin appears to be proposing a semi-reusable ISS cargo spacecraft for 2018. I haven't read much yet, but it looks like they are proposing a long-term satellite called Jupiter that would dock with cargo modules called Exoliner and then dock with the ISS. The Exoliner modules would contain pressurized and unpressurized sections, as well as a fuel tank to refuel the Jupiter satellite/spacecraft. I think I read that it might be possible for Jupiter to do other work, such as launching cubesats, after it shuffles the Exoliner craft around. The theory is that they could launch more cargo in an unpowered (or underpowered) module and leave the satellite/tug in orbit. To be honest, I have reservations about this since I don't know if oribtal refueling like this have been done before, but I don't know. I'm not sure if this a serious proposal by LM or just a pie-in-the-sky idea to see if they would get any funding to look into it.

Article:

http://spaceflightnow.com/2015/03/17/lockheed-martin-throws-its-hat-into-iss-cargo-competition/

[Nibb31]

It's the old (very old) concept of a space tug. The idea makes sense on paper: keep the propulsion module on orbit and only launch dumb canisters.

In practice, it's a different story though (like always). In order for the tug to dock with the canister, the canister is going to need some sort of attitude control, which means that it needs avionics, power, and RCS. It needs to carry the propellant to refill the tug for the next mission. After the rendez-vous with the station, the tug needs to deorbit the canister and reboost itself into orbit, which is going to waste a lot of dV, meaning that the canister has to bring along more propellant than if it just had to rendez-vous and deorbit itself. The canister also needs two docking systems instead of one, one to dock with the tug and the other to dock with the target.

So in the end, if your cargo canister has a docking system, avionics, RCS and propellant, then it might as well just fly itself to the destination. The tug idea doesn't save a lot in terms of mass, but adds a lot of complexity to the mission because you have an additional docking event and two vehicles to control instead of one.

Edited March 17, 2015 by Nibb31

[Motokid600]

How many cargo craft does the ISS need? We got Progress, ATV ( discontinued? ), Dragon and Cygnus.

[magnemoe]

RL version of the KSP RCS tug for docking modules with space stations or ships, this however will also do to the ISS approach.

Refueling in orbit has been done before at least the Russian docking ports support it, with the robotic arm connecting fuel lines should be possible anyway.

More skeptical to the module swapping who sounds harder.

[Nibb31]

How many cargo craft does the ISS need? We got Progress, ATV ( discontinued? ), Dragon and Cygnus.

The ATV program is finished. No more flights.

The current CRS-1 cargo contracts end in 2017. This is for the second round of cargo flights, called CRS-2. LM and Boeing are competing against Dragon and Cygnus. Boeing is offering a stripped-down cargo version of CST-100. Cygnus is probably renewing its current offering. We don't know yet if SpaceX is going to offer Dragon v1 or v2 for CRS-2.

IMO, LM's Jupiter has very little chances. It looks very over-engineered for CRS-2 (the robot arm in particular) and NASA doesn't have any plans for using it for other missions.

[Kryten]

It's the old (very old) concept of a space tug. The idea makes sense on paper: keep the propulsion module on orbit and only launch dumb canisters.

In practice, it's a different story though (like always). In order for the tug to dock with the canister, the canister is going to need some sort of attitude control, which means that it needs avionics, power, and RCS. It needs to carry the propellant to refill the tug for the next mission. It also needs two docking systems instead of one, one to dock with the tug and the other to dock with the target. In the end, if your cargo canister has a docking system, avionics, RCS and propellant, then it might as well just fly itself to the destination.

You really don't save a lot in terms of mass, and you add a lot of complexity to the mission because you have an additional docking event and two vehicles to control instead of one.

The idea in this case is to use the Centaur avionics and RCS systems to facilitate docking, and use an arm to insert it into the structure rather than a proper docking system.

How many cargo craft does the ISS need? We got Progress, ATV ( discontinued? ), Dragon and Cygnus.

Also HTV. This is a proposal for the CRS-2 program, which would replace the CRS-1 vehicles (cargo dragon and cygnus). So far we know of at least five competitors; LM Jupiter, SNC Dreamchaser cargo, Boeing CST-100 cargo, Cygnus, and the SpaceX proposal. BLue Origin have also refused to confirm or deny if they're pursuing the contract.

[magnemoe]

It's the old (very old) concept of a space tug. The idea makes sense on paper: keep the propulsion module on orbit and only launch dumb canisters.

In practice, it's a different story though (like always). In order for the tug to dock with the canister, the canister is going to need some sort of attitude control, which means that it needs avionics, power, and RCS. It needs to carry the propellant to refill the tug for the next mission. It also needs two docking systems instead of one, one to dock with the tug and the other to dock with the target. In the end, if your cargo canister has a docking system, avionics, RCS and propellant, then it might as well just fly itself to the destination.

You really don't save a lot in terms of mass, and you add a lot of complexity to the mission because you have an additional docking event and two vehicles to control instead of one.

The container is connected to the centaur upper stage who handle its station keeping until docked with jupiter. The Jupiter docking port can be smaller and simpler, think they plan using the arm to assist docking, the other side contains the ISS hatch.

Only think I don't understand is how to swap containers, this require that its able to dock the used containers with the centaur.

However this step might be optional it should be other ways to deorbit the containers.

[GreenWolf]

How many cargo craft does the ISS need? We got Progress, ATV ( discontinued? ), Dragon and Cygnus.

Each of those cargo vehicles is manufactured and operated by different entities, and each one serves a different purpose. Progress is useful for sending up pressurized cargo and more propellant for the RCS, but has very poor downmass capability. Dragon, on the other hand, can return cargo to Earth, is partially reusable, and will eventually be used to carry crew. Cygnus has no downmass capability at all and has slightly less payload capacity than Progress and far less than Dragon.

Additionally, having multiple different vehicles operated by different people makes the station more resistant to the retirement of one of the cargo craft. When the Space Shuttle was retired, the ISS lost most of its downmass capability for a significant amount of time. Having three cargo vehicles will help prevent a similar situation in the future.

[Nibb31]

The idea in this case is to use the Centaur avionics and RCS systems to facilitate docking, and use an arm to insert it into the structure rather than a proper docking system.

Makes sense. I'm not sure how long a Centaur can stay alive on orbit, but it might need upgraded batteries to wait until the tug arrives. The canister still needs to bring along more propellant than usual though, because the tug needs to deorbit and reboost itself into orbit, which requires more dV than a simple deorbit.

Also HTV. This is a proposal for the CRS-2 program, which would replace the CRS-1 vehicles (cargo dragon and cygnus). So far we know of at least five competitors; LM Jupiter, SNC Dreamchaser cargo, Boeing CST-100 cargo, Cygnus, and the SpaceX proposal. BLue Origin have also refused to confirm or deny if they're pursuing the contract.

Have the SNC and SpaceX proposals been published yet?

[Frida Space]

How many cargo craft does the ISS need? We got Progress, ATV ( discontinued? ), Dragon and Cygnus.

Let's not forget the Japanese HTV! The fifth one will launch on Aug 17th, 2015.

[Kryten]

Makes sense. I'm not sure how long a Centaur can stay alive on orbit, but it might need upgraded batteries to wait until the tug arrives. The canister still needs to bring along more propellant than usual though, because the tug needs to deorbit and reboost itself into orbit, which requires more dV than a simple deorbit.

Centaur handles deorbit. As far as I can tell it's dependent on IVF centaur being available for increased lifespan.

Have the SNC and SpaceX proposals been published yet?

SNC are doing a press conference on it today, we should get everything then. Nothing from SpaceX yet.

[Airlock]

SNC are doing a press conference on it today, we should get everything then. Nothing from SpaceX yet.

Here's SNC's proposal. Direct competition for SpaceX's Dragon in returning cargo from space.

Sierra Nevada Space Systems unveils new folding-wing Dream Chaser

Edited March 17, 2015 by Airlock

[Motokid600]

Thanks for the clarification everyone.

[The_8th_Bit]

I wonder if Lockheed Martin has considered using the tug for other purposes when not delivering cargo. It could be used to repair or deorbit satellites reducing orbital debris.

[Tommygun]

I wonder if Lockheed Martin has considered using the tug for other purposes when not delivering cargo. It could be used to repair or deorbit satellites reducing orbital debris.

I think repairing satellites in orbit is still too hard right now for robotic craft. Look at the effort it took to do the Hubble missions.

Companies would need to first design their satellites to be repairable and modular before there would be any chance to repair them.

Otherwise you might just end up creating more space debris removing bolts, drilling and cutting off parts of body panels.

You would probably need a government mandate to get companies to spend money to deorbit dead spacecraft too and I don't see much interest in that from Congress.

[Rakaydos]

An orbital tug needs to be an order of magnatude more efficent than a normal drive system to make up for all the extra burns it needs.

Thats why I feel an electrodynamic tether based tug is the best bet. It "cheats" by using earth's magnetic field to push off of, instead of conventional propellant. Not useful for deep space exploration, but amazing for low earth operations.

[PB666]

According to one article I saw in Spaceflight Now, Lockheed Martin appears to be proposing a semi-reusable ISS cargo spacecraft for 2018. I haven't read much yet, but it looks like they are proposing a long-term satellite called Jupiter that would dock with cargo modules called Exoliner and then dock with the ISS. The Exoliner modules would contain pressurized and unpressurized sections, as well as a fuel tank to refuel the Jupiter satellite/spacecraft. I think I read that it might be possible for Jupiter to do other work, such as launching cubesats, after it shuffles the Exoliner craft around. The theory is that they could launch more cargo in an unpowered (or underpowered) module and leave the satellite/tug in orbit. To be honest, I have reservations about this since I don't know if oribtal refueling like this have been done before, but I don't know. I'm not sure if this a serious proposal by LM or just a pie-in-the-sky idea to see if they would get any funding to look into it.

Article:

http://spaceflightnow.com/2015/03/17/lockheed-martin-throws-its-hat-into-iss-cargo-competition/

I doubt they can do it, they are having problem fulfilling their contract obligations with the joint strike fighter.

[Nibb31]

Centaur handles deorbit. As far as I can tell it's dependent on IVF centaur being available for increased lifespan.

I don't get it. How does the Jupiter put the Exoliner back onto the Centaur ? At some point in that mission profile, either it needs to be handling two Exoliners at the same time, or it needs to do several runs between the Centaur and the station. How long does the Centaur have to loiter while the Jupiter does all this shuffling around ?

- - - Updated - - -

I doubt they can do it, they are having problem fulfilling their contract obligations with the joint strike fighter.

Space and aircraft are totally different divisions.

[magnemoe]

An orbital tug needs to be an order of magnatude more efficent than a normal drive system to make up for all the extra burns it needs.

Thats why I feel an electrodynamic tether based tug is the best bet. It "cheats" by using earth's magnetic field to push off of, instead of conventional propellant. Not useful for deep space exploration, but amazing for low earth operations.

This however is not an real orbital tug, its more like the RCS tugs we use in KSP to handle payloads, say from spaceplane to station.

Main reason is to keep the cost down in that they don't need the approach and docking systems on each payload, upper stage handles the station-keeping during docking with it, as in keep orientation and no spin, it uses an arm to help docking.

For an real orbital tug you are right.

[Kryten]

I don't get it. How does the Jupiter put the Exoliner back onto the Centaur ? At some point in that mission profile, either it needs to be handling two Exoliners at the same time, or it needs to do several runs between the Centaur and the station. How long does the Centaur have to loiter while the Jupiter does all this shuffling around ?

There appears to be an extra end effector at the back of Jupiter, so it should be able to hold one in place while handling another. With the IVF upgrade, Centaur lifetime should be multiple days.

[billbobjebkirk]

I don't get it. How does the Jupiter put the Exoliner back onto the Centaur ? At some point in that mission profile, either it needs to be handling two Exoliners at the same time, or it needs to do several runs between the Centaur and the station. How long does the Centaur have to loiter while the Jupiter does all this shuffling around?

My impression was that they were using the Centaur from the next Exoliner launch.

[Nibb31]

My impression was that they were using the Centaur from the next Exoliner launch.

Sure, but then what ? How does the Jupiter remove the new Exoliner and put the old Exoliner on the Centaur when both the Jupiter and the Centaur can only be attached to one Exoliner at a time?

Imagine holding two footballs, one in each hand. How do you swap them around without dropping one of the footballs?

Edited March 18, 2015 by Nibb31

[billbobjebkirk]

Sure, but then what ? How does the Jupiter remove the new Exoliner and put the old Exoliner on the Centaur when both the Jupiter and the Centaur can only be attached to one Exoliner at a time?

Imagine holding two footballs, one in each hand. How do you swap them around without dropping one of the footballs?

you put one down for a second, then grab it once you're done.

[Kryten]

Sure, but then what ? How does the Jupiter remove the new Exoliner and put the old Exoliner on the Centaur when both the Jupiter and the Centaur can only be attached to one Exoliner at a time?

Imagine holding two footballs, one in each hand. How do you swap them around without dropping one of the footballs?

There's an extra end effector at the back of Jupiter.

[Pixel of Life]

Sure, but then what ? How does the Jupiter remove the new Exoliner and put the old Exoliner on the Centaur when both the Jupiter and the Centaur can only be attached to one Exoliner at a time?

The question is, can the Exoliner be attached to more than one thing at once? If so, they could use the old module to pull the new one out of the Centaur, then disconnect the Jupiter, flip it around, move it to the other end of the Exoliner stack, connect, turn the whole thing around again and then place the old module inside the Centaur. Doesn't sound very fuel/time efficient though.

E: Oh so apparently that isn't a problem.