Finally. Someone's talking about on orbit refueling/spacecraft repair.

[Aethon]

DARPA, The US Defense Advanced Research Projects Agency no less.

https://www.fbo.gov/index?s=opportunity&mode=form&id=a5ba9b924872fe7f6b2169e4e2a73bcc&tab=core&_cview=0

Here's a pop sci article.

http://www.space.com/27128-darpa-robotic-satellite-repair-droids.html

Please let this be a move towards an effective space based infrastructure.

Edited September 12, 2014 by Aethon

[mangekyou-sama]

Correct me if I'm wrong but isn't this what the Constellation program was about?

[Kryten]

Correct me if I'm wrong but isn't this what the Constellation program was about?

Yep, that's completely wrong. Constellation was basically Apollo II, to be followed my a crewed Mars landing.

[Tommygun]

I like how DARPA stresses cooperatively inspects and repairs satellites in their statement and illustrations several times.

"This is NOT a spy/anti satellite system."

I think refueling/orientation modules will be the first thing you see come out of this. Something you can just attach to a satellite.

I know they want to promote a universal mount for future spacecraft to make this easier.

Recycling and repair are several times more difficult, but you have to start somewhere.

[magnemoe]

I like how DARPA stresses cooperatively inspects and repairs satellites in their statement and illustrations several times.

"This is NOT a spy/anti satellite system."

I think refueling/orientation modules will be the first thing you see come out of this. Something you can just attach to a satellite.

I know they want to promote a universal mount for future spacecraft to make this easier.

Recycling and repair are several times more difficult, but you have to start somewhere.

Cooperative makes sense as you share the cost, having an universal mount/ interface for docking, refueling and adding modules also make sense, especially if you imagine the refuel and repair robot work probe is reused so it refuels and pick up new modules in leo.

Lots of stuff can be done with just adding another module, think adding an grapic card to your computer to replace the on board graphic chip.

Having an ISP engine like vasmir would give more capabilities, you could then use this for lifting satellites upo to geo, then perhaps service some other satellites before returning.

This would also open the door for recycling and repair as you could then bring another satellite down down to leo for actual repair work or even recycling.

Russia has this of one of their planned operations for the future space stations.

[Nibb31]

Comsats are already transitioning to high-Isp electrical propulsion. They are already built to run for about 20 years. How much longer do you thing you would want to extend their life if you could? You would be able to upgrade some stuff, but the chassis and the basic components will not be replaceable. To go back to the PC analogy, even if you replace the video card and RAM every 2 years, you would still be stuck with a 20 year old motherboard and PSU. Most of the parts will be obsolete, the technology no longer useful. Actually, in 20 years, we probably won't be using GEO comsats any more...

Repairable and refuelable satellites have to designed with that in mind, meaning that the hundreds of GEO comsats that are operating today will never be repairable.

How much does the extra hardware for docking and refueling weigh compared to adding a few kg of extra xenon in the first place? As for hardware replacement, that's even heavier, because it requires doors, rack-mounts, base plates, special connectors... (cf Hubble) everything has to be modular and easily accessible from the outside. You are better off using higher grade components, thicker shielding, and add more fuel, if you are interested in squeezing more life out of a satellite.

And if you really have to replace all those parts, you're probably better off just sending up a new sat, with all the latest technology and materials. It will probably be lighter, more optimized, and purpose built for the new communication technologies that you want it to handle over the next 20 years.

Edited September 13, 2014 by Nibb31

[magnemoe]

Comsats are already transitioning to high-Isp electrical propulsion. They are already built to run for about 20 years. How much longer do you thing you would want to extend their life if you could? You would be able to upgrade some stuff, but the chassis and the basic components will not be replaceable. To go back to the PC analogy, even if you replace the video card and RAM every 2 years, you would still be stuck with a 20 year old motherboard and PSU. Most of the parts will be obsolete, the technology no longer useful. Actually, in 20 years, we probably won't be using GEO comsats any more...

Repairable and refuelable satellites have to designed with that in mind, meaning that the hundreds of GEO comsats that are operating today will never be repairable.

How much does the extra hardware for docking and refueling weigh compared to adding a few kg of extra xenon in the first place? As for hardware replacement, that's even heavier, because it requires doors, rack-mounts, base plates, special connectors... (cf Hubble) everything has to be modular and easily accessible from the outside. You are better off using higher grade components, thicker shielding, and add more fuel, if you are interested in squeezing more life out of a satellite.

And if you really have to replace all those parts, you're probably better off just sending up a new sat, with all the latest technology and materials. It will probably be lighter, more optimized, and purpose built for the new communication technologies that you want it to handle over the next 20 years.

Note that the air force is developing this for themselves, they want it for their recon satellites, many fly in lower orbits and need refueling. Making it public is a way to share costs.

Almost all of the docking system would be on the service probe, the satellite already has to have an interface to the launcher so an modified version can be used for docking.

You would need an refueling port at the center of the docking port and an electrical connector who can be plugged, this would add some weight.

[Sky_walker]

"Finally"?!

Oh come on, ESA has been building that for years. In November they launch IXV - the first test vehicle of a future spacecraft that will do exactly the same.

Nice to see that DARPA catches up, but please, don't misinform people that it's something new or they're the first. Concepts for ships like that have been floating at least since '60s.

[TNM]

The title sounds a bit grandiouse, this is more about satellite servicing, which is, of course, long overdue.

Will it work out economically? Who knows, there is still the fact that you may prefer putting a new satellite up with new technology instead of refueling the old one after 10 years. Broadcast tech changes alot in 10 years, so do all other instruments.

[Nibb31]

"Finally"?!

Oh come on, ESA has been building that for years. In November they launch IXV - the first test vehicle of a future spacecraft that will do exactly the same.

Huh? IXV has nothing to do with refueling or repairing. It's a suborbital reentry research vehicle.

[TNM]

Here, ESA 2012 is calling Nobody want's to talk this down, for many space-geeks its just not the first time we hear about it, thats all, many are interested in some basic tech that allows that, the whole ATV-fully automated docking was part of that long term goal to do automated servicing in space.

Astrium wins satellite servicing contract

[Sky_walker]

Huh? IXV has nothing to do with refueling or repairing. It's a suborbital reentry research vehicle.

Read carefully. I never said that IXV will be the one servicing satellites. The final goal of the programme that involves IXV is to develop a reusable spacecraft that will be capable of servicing satellites.

Here, ESA 2012 is calling Nobody want's to talk this down, for many space-geeks its just not the first time we hear about it, thats all, many are interested in some basic tech that allows that, the whole ATV-fully automated docking was part of that long term goal to do automated servicing in space.

Astrium wins satellite servicing contract

Astrium will be servicing a satellite made of Probodobodyne OKTO and Communotron 88-88.

Oh, by the way - here's some more recent and detailed info from the DLR website: http://www.research-in-germany.de/dachportal/en/Research-Areas-A-Z/Space-Technology/Research-Projects/DEOS.html

Launch will take place in 2018.

Edited September 14, 2014 by Sky_walker

[Nibb31]

Read carefully. I never said that IXV will be the one servicing satellites. The final goal of the programme that involves IXV is to develop a reusable spacecraft that will be capable of servicing satellites.

No it isn't. IXV's purpose is to study advanced reentry technologies as part of the FLPP program. Reentry has nothing to do with servicing satellites, nor has the FLPP got anything to do with servicing satellites.

A servicing spacecraft will have to be much simpler and cheaper than the mission satellite that it is supposed to service, otherwise you might as well just relaunch a new mission satellite and forget about the servicing. It will basically be a tanker, a manoeuvering system and a docking mechanism. Once it's done, it's just an empty tank. There is no point in bringing it back. You will be better off giving it a larger tank to allow it to service more satellites rather than to add wings, a TPS, hydraulics and all sorts of expensive hardware to bring it back.

Edited September 14, 2014 by Nibb31

[Sky_walker]

No it isn't. IXV's purpose is to study advanced reentry technologies as part of the FLPP program. Reentry has nothing to do with servicing satellites, nor has the FLPP got anything to do with servicing satellites.

You're still confusing things.

Perhaps picture will help:

IXV won't do that, PRIDE might, though it probably will be decided in December for sure, it's successor however will be fully fledged spaceplane capable of servicing satellites.

A servicing spacecraft will have to be much simpler and cheaper than the mission satellite that it is supposed to service, otherwise you might as well just relaunch a new mission satellite and forget about the servicing. It will basically be a tanker, a manoeuvering system and a docking mechanism. Once it's done, it's just an empty tank. There is no point in bringing it back. You will be better off giving it a larger tank to allow it to service more satellites rather than to add wings, a TPS, hydraulics and all sorts of expensive hardware to bring it back.

Lower long-term cost thanks to reusability, lack of space debris, ability to perform multiple varied missions, ability to retrieve cargo (what opens a whole lot of possibilities with space probes) / broken components (for further analysis) / microsatellites (european ... geckos ). I can think of few reasons why spaceplane would be better than one-shot-spacecraft like the one build by Astrium.

Edited September 14, 2014 by Sky_walker

[Nibb31]

You're still confusing things.

Perhaps picture will help:

http://www.esa.int/var/esa/storage/images/esa_multimedia/images/2012/11/pride_mission3/12117599-4-eng-GB/PRIDE_mission_node_full_image_2.jpg

IXV won't do that, PRIDE might, though it probably will be decided in December for sure, it's successor however will be fully fledged spaceplane capable of servicing satellites.

They are experimental vehicles designed to study new fundamental technologies. Those techologies might or might not one day lead to economically viable applications.

Most spacecraft are expendable, because making them recoverable only adds to the weight and complexity. You only design them to reenter if they are carrying something valuable enough to justify the extra cost of making the vehicle capable of reentry, such as humans, scientific samples, or very expensive engines. Cheap stuff like tankage, computers, solar panels, or insulation materials don't justify that expense and are therefore expendable.

Building a reusable spacecraft whose only justification for being recoverable is the cost of the equipment that makes it reusable doesn't make any sense.

A reusable tanker that is only going to return an empty tank simply doesn't make any sense at all.

Lower long-term cost thanks to reusability, lack of space debris, ability to perform multiple varied missions, ability to retrieve cargo (what opens a whole lot of possibilities with space probes) / broken components (for further analysis) / microsatellites (european ... geckos ). I can think of few reasons why spaceplane would be better than one-shot-spacecraft like the one build by Astrium.

Vehicles like X37B or IXV (or PRIDE) are not reusable rockets. You still need a full-size expendable rocket to put them into space. They are very expensive reusable payload fairings that take up most of the expendable launcher's payload capacity, which is why they make no sense economically.

[sgt_flyer]

well, ESA tested the LIRIS system (Laser InfraRed Imaging Sensors ) on the latest ATV - it would allow close proximity / docking with uncooperative targets (ie, they don't have the counterparts needed for 'classic' automated docking systems - reflectors or antenna's)

they tested the system before doing their standard automatic docking on ISS.

so this technology is already a huge step forward to servicing satellites (as will it enable to do rendez-vous and stable stationkeeping with an object long enough to claw it)

without a similar technology, it would be hard to do anything with old satellites (or new ones would need to be cooperative targets for docking - which would add weight to a satellite )

Edited September 14, 2014 by sgt_flyer

[StrandedonEarth]

It is a shame spacecraft engineers aren't (or weren't) a little more forward thinking, to equip satellites for the possibility of being visited by a servicing craft. I hope they start doing that now, hopefully the extra weight/complexity/cost wouldn't make it prohibitive. Imagine being able to reload Spitzer's liquid helium supply to extend the full capabilities of that billion-dollar piece of hardware

[Starwaster]

Love the acrimony and bitchfesting.

Someone here needs to curb their hostility.

This is still big news whether you care to admit it or not.

(you know who you are now give it a rest)

[Sky_walker]

It is a shame spacecraft engineers aren't (or weren't) a little more forward thinking, to equip satellites for the possibility of being visited by a servicing craft.

Noone does it for a few reasons:

1) There are no standards for refueling. Even the International Docking System Standard doesn't have any connectors allowing for a fuel transfer.

2) There are no spacecrafts performing refueling and added weight means less payload or less fuel onboard your satellite. So either you put the equipment for refuelling that might never be used or you add more fuel extending lifetime of your satellite for sure.

They are experimental vehicles designed to study new fundamental technologies. Those techologies might or might not one day lead to economically viable applications.

ESA doesn't build IXV just for a sake of studying technologies. It's a clear path leading to a future autonomous spaceplane, and one of it's roles will be to service other spacecrafts / satellites. And let me stress it again: It's not the only role for it.

You only design them to reenter if they are carrying something valuable enough to justify the extra cost of making the vehicle capable of reentry, such as humans, scientific samples, or very expensive engines.

I already mentioned that in my post.

Building a reusable spacecraft whose only justification for being recoverable is the cost of the equipment that makes it reusable doesn't make any sense.

Read carefully. I already pointed out that it's not a reusability for the sake of re-usability. You are the one suggesting that, not me.

A reusable tanker that is only going to return an empty tank simply doesn't make any sense at all.

Yea, it won't. That's why noone is building reusable tanker, but rather very versatile craft capable of performing multiple different missions in a single flight. Remember that with the use of electric propulsion refuelling isn't a problem - servicing satellites is. Propulsion systems will actually start outliving other hardware on the satellites (you'll notice the increasing number of redundant systems on a newly deployed satellites). Refuelling itself isn't a priority, especially when you consider that there are no standardized ways to refuel satellites and any non-standard ideas that exist for refuelling are still in an experimental stage at the moment.

Vehicles like X37B or IXV (or PRIDE) are not reusable rockets. You still need a full-size expendable rocket to put them into space. They are very expensive reusable payload fairings that take up most of the expendable launcher's payload capacity, which is why they make no sense economically.

Never said that they are reusable rockets. But think of that: Either you pay ~13M euro for each Astrium servicing spacecraft or you pay once for a spaceplane and reuse it for multiple missions, including an ability to perform several different tasks in a single flight bringing the payload back from space (eg. scientific experiments + servicing a satellite/space probe/space telescope mission profile).

Edited September 15, 2014 by Sky_walker

[sgt_flyer]

Mmh - i wonder if a service spacecraft - instead of refuelling other satellites which don't have the required docking fuel systems - if it could grab out of order sats which still have fuel, and drain their tanks through one way or another (puncturing the fuel lines with a needle like tool for example) - so, with the additional fuels / pressurant it could gather, use these fuels to claw a still functionning satellite which still have fuel for a few manoeuvers, but not enough for big orbital changes, and simply change the satellite's orbit so it can resume it's mission.

That way, the service spacecraft could extend it's mission time in orbit like a vampire

[Nibb31]

Yea, it won't. That's why noone is building reusable tanker, but rather very versatile craft capable of performing multiple different missions in a single flight. Remember that with the use of electric propulsion refuelling isn't a problem - servicing satellites is. Propulsion systems will actually start outliving other hardware on the satellites (you'll notice the increasing number of redundant systems on a newly deployed satellites). Refuelling itself isn't a priority, especially when you consider that there are no standardized ways to refuel satellites and any non-standard ideas that exist for refuelling are still in an experimental stage at the moment.

Yes, but a robot (and even a human in EVA) can only service parts that are designed to be serviceable, ie. you know in advance that the parts have a limited lifecycle, either because they will wear out (stuff like CMGs), or they have planned obsolescence.

You can't predict that a future technology will be available in 10 years to the point where you can design your system to be compatible with that technology because satellite components are usually highly integrated.

You could overengineer your other components to cope with a higher performance or larger capabilities that might be available in the future, but that would just make it much more expensive. As for mechanical wear, that's what redundancy is for, and you design your system so that all parts have a similar MTBF. There is no point in adding more propellant than necessary for the lifetime of other parts of the spacecraft, or in overengineering CMGs that will outlive the rest of the system.

All in all, the uses for actual on-orbit servicing are quite limited. We have Hubble as an example to demonstrate that orbital repairs are expensive and hazardous. It would have been cheaper to launch an improved Hubble 2 than to perform all those maintenance flights.

Never said that they are reusable rockets. But think of that: Either you pay ~13M euro for each Astrium servicing spacecraft or you pay once for a spaceplane and reuse it for multiple missions, including an ability to perform several different tasks in a single flight bringing the payload back from space (eg. scientific experiments + servicing a satellite/space probe/space telescope mission profile).

That's not how it works. You have to relate the cost of the servicing with the cost of the mission spacecraft. If your satellite costs 200 million to design and 200 million to build and launch, and your servicing mission costs 100 million, then you're better off launching a copy of your original satellite than messing with servicing, especially if you can save 100 million by not adding serviceability requirements to your design.

And your servicing spacecraft could do much more servicing if it is expendable than if it isn't. For a constant launch cost, a 10 ton spaceplane only has a few hundred kilos of mission payload (spare parts, refueling consumables, robotic equipment), whereas a 10 ton expendable servicing spacecraft could carry several tons of mission payload and be able to do a lot more work. The wings, fuselage, wheels, TPS, hydraulics are all just wasted payload, because your spaceplane isn't going to bring back anything of much value.

Edited September 15, 2014 by Nibb31

[Sky_walker]

Yes, but a robot (and even a human in EVA) can only service parts that are designed to be serviceable, ie. you know in advance that the parts have a limited lifecycle, either because they will wear out (stuff like CMGs), or they have planned obsolescence.

Read the article I linked to - NASA is experimenting with servicing the satellites that weren't designed for that.

Just to prevent you from missing it again, here is a clear, direct link to Wikipedia: https://en.wikipedia.org/wiki/Robotic_Refueling_Mission

All in all, the uses for actual on-orbit servicing are quite limited. We have Hubble as an example to demonstrate that orbital repairs are expensive and hazardous.

Yea, that's why you want robots to perform them, not humans. But obviously you are right - it's easier to perform repairs on a satellite that was build to be modular than one that hardly can be de-assembled. Thankfully modularity is a constantly growing trend in satellite design. Still though quite a lot can be done with just a single cleverly build spacecraft designed with repairs in mind. Eg. you could fix solar panels or antennas that got "stuck" while unfolding (both being quite common issues that are easily "fixable" without having a spacecraft intentionally designed for that (heck, usually combination of heating from sun with spin is enough to "unstuck" them) ).

It would have been cheaper to launch an improved Hubble 2 than to perform all those maintenance flights.

Well... not really. If I remember well - Hubble was more expensive than it's launch, even with horrendous launch costs of the Space Shuttle.

And that mission had an added scientific value. So it was worth performing it.

That's not how it works. You have to relate the cost of the servicing with the cost of the mission spacecraft. If your satellite costs 200 million to design and 200 million to build and launch, and your servicing mission costs 100 million,

That's not how it works. You can't pull assumptions like that out of the sleeve. In some cases it will be cheaper to send a replacement (eg. for communication satellite) - in other cases it'll be cheaper to prolong life of an existing satellite (eg. for some more expensive scientific satellites)

And your servicing spacecraft could do much more servicing if it is expendable than if it isn't. For a constant launch cost, a 10 ton spaceplane only has a few hundred kilos of mission payload (spare parts, refueling consumables, robotic equipment), whereas a 10 ton expendable servicing spacecraft could carry several tons of mission payload and be able to do a lot more work. The wings, fuselage, wheels, TPS, hydraulics are all just wasted payload, because your spaceplane isn't going to bring back anything of much value.

Yes, you are correct. That's why ESA isn't building a reusable spaceplane that only does servicing, and servicing alone.

Please, finally start reading carefully, I already pointed that out 3 times and you still insist that I never said anything like that.

We do agree! Reusable spacecraft on this scale build only for servicing and servicing alone doesn't make much sense. But that's not what ESA builds!

Sorry, but I give up. There's only as many times as I can explain the same thing over and over again and you still refuse to even process what I'm writing.

See you in another topic, I'm out from here.

Edited September 15, 2014 by Sky_walker

[Kryten]

Well... not really. If I remember well - Hubble was more expensive than it's launch, even with horrendous launch costs of the Space Shuttle.

And that mission had an added scientific value. So it was worth performing it.

It cost more than it's launch, yes, but that includes development costs. With development done, and a number of spare parts ready to use, a second one would have been significantly cheaper.

[Sky_walker]

AFAIK construction cost alone was over 2 billion USD, development cost was ~10 billion.

Space shuttle launch cost was ~1.5 billion USD.

So: no, it doesn't include development cost.

With development done, and a number of spare parts ready to use, a second one would have been significantly cheaper.

Probably. But it's pure speculation at this stage on just how much cheaper would it be.

Edited September 15, 2014 by Sky_walker

[sojourner]

Been reading the thread and thought of a scenario that might work.

The most costly failure (besides total launch failure) is a launch that results in the incorrect orbit being achieved. You end up with a brand new satellite in a totally unworkable location.

So this is where the strength of a totally reusable launch system comes into play. Say we have the F9R at it's operational peak design intention of 1st and 2nd stage re-usability. What if SpaceX developed a "rescue" craft payload? Basically an engine with good DV, tankage, throw it in a reusable bus based on Dragon and a way to grab our errant satellite and move it to it's intended orbit. . Keep the whole setup on standby at one of their launch facilities.

Now they are in a position to save someone's 200million dollar comsat for the minimal cost of a Falcon9 launch (which they are hoping to be less than $10mil in this configuration) and a reusable payload that needed minimal development. How many comsat owners would pay for that service?

Would be a great service to offer from a PR viewpoint even if it never actually gets used. "You launched with another provider and the rocket failed? No problem, we can fix that for you. Next time just consider using us in the first place" Heck, they could even offer it as a free service on their own launches. further reducing risk. "Well, our rocket didn't quite do it's job. No problem, we're warming up Thunderbird 1 to make the correction now. No charge, of course".

Edited September 15, 2014 by sojourner