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showtime17

Banned

From: Montreal

Registered: 2004-05-23

Posts: 26

Re: Space tug

A space tug to fix satellites and other things is being developed in Europe.

" Extending the life of telecommunication satellites which often cost some 300 million euros to build and launch is economically advantageous. Resorting to a CX-OLEV mission, at an all-inclusive price of around 60 million euro, will prolong their operations for up to ten years.

Alternatively, the 'space tug' could be used for rescue missions, to store a satellite near the geostationary orbit for contingency purposes, or even to remove no-longer operational craft, propelling them to the so-called "graveyard orbit" 300 km higher up."

The entire article is here
http://www.spacedaily.com/news/salvage-05c.html

Dook

Banned

From: USA

Registered: 2004-01-09

Posts: 1,409

Re: Space tug

It seems to me there's finally a reason for the ISS.  Use a small space tug to capture damaged/old satellites and bring them to the ISS for repair. 

I wonder if the space tug could even be automated?

Commodore

Member

From: Upstate NY, USA

Registered: 2004-07-25

Posts: 1,021

Re: Space tug

The article discusses the maintaining of orbit, there doesn't seem to be any repairing going on here. I would think that this would be a great thing if they could bundle multiple tugs together on the second stage this or scale the launcher. The bigger the launcher required the less sense it makes. Also, don't push junk out farthur, deorbit it.

That doesn't mean repairing them is a bad idea. But it makes little sense when the satillite is not designed to be easily upgraded. Think of it like upgrading your computer. If you want to replace your CPU, but need to replace the motherboard (and then the video card and the power supply) to do it, it might be time to replace the whole shabang.

It would only really work if they were designed to industry standards to have interchangable and upgradeable parts.

---

"Yes, I was going to give this astronaut selection my best shot, I was determined when the NASA proctologist looked up my ass, he would see pipes so dazzling he would ask the nurse to get his sunglasses."
---Shuttle Astronaut Mike Mullane

GCNRevenger

Member

From: Earth

Registered: 2003-10-14

Posts: 6,056

Re: Space tug

Designing a satelite to be serviced by robots on orbit would make their price balloon alot. If you are going to be hauling up new electronics, new batteries, and fresh fuel you might as well bring up a new chassis and solar pannels while you're at it... in which case you are better off just launching a new satelite.

Satelite repair doesn't make alot of sense. Their electronics become obsolete almost as fast as they wear out.

Oh, and risk is a big factor too: which is more reliable, a repair robot that has to rendezvous, guts the satelite and puts it back together, and then reboosts it to a perfect orbit... or just launching another.

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[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

PurduesUSAFguy

Banned

From: Purdue University

Registered: 2004-04-04

Posts: 237

Re: Space tug

Launch mass wise repairing sats won't make sense until the replacement parts are produced in space, in which case why not just build a new sat.

GCNRevenger

Member

From: Earth

Registered: 2003-10-14

Posts: 6,056

Re: Space tug

Which isn't going to happen, maybe not ever

Lets say the really intricate electronics (chips, circut boards, etc) are still imported, but you want to make replacement stuff in space? One big problem with this is the supply of certain elements that aren't available.

You need metals for batteries, like Lithium, Cadmium, Lead, Silver, or Zinc. Perhaps a supply of sulfur too.

You need Nitrogen to make Hydrazine mono/hypergolic propellant for rocket fuel, and a rather complex machine for making the stuff. Did I mention its tendency to blow up and degrade under UV radiation?

Say you want to use an ion engine instead of a rocket? Well, then you are going to need some heavy working fluid, like Xenon, Krypton, Cesium, or Mercury.

We have all these things right here on Earth, but none of them readily available in space, so even if you did have a space satelite parts factory you are still going to have to lift signifigant masses from Earth.

Even manufacturing aluminum for a frame and silicon for solar cells would be hard, especially since traditional silicon manufacturing uses gravity.

---

[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

Jboily

Banned

Registered: 2006-09-05

Posts: 1

Re: Space tug

All of your comments are correct, in some ways.

My company is also developing a space tug similar to Orbital Recovery, although we do not advertise as much

The lunch cost of the hardware is not the main factor in the cost of the mission.  The development and operation over the tug over the rescue mission time is very costly, not counting the cost of the risk of using a new design in the GEO ring (either through direct insurance costs or self insured risk of failure).

We find it very difficult to justify a single mission, even if the total cost of the rescue is less then 50%.  The main reason is the risk of failure of the old satellite.  Regardless, there are some very expensive satellites that will worth a mission.

These life extension missions are the first step in this market.  As the robotic rescue business side of the industry mature, the customers (the Commercial operators) will want their new satellites with some upgrades capability to reduce the risk of major failures like a station keeping engine failing, or a solar array shorting out.  At this time, we can not offer upgrade services, because the satellites are not designed for it, and they will not be designed for until simpler successful missions do happen.

It does not make sense at this time to bring the satellite back down to LEO for human interventions.  It is too costly and risky (for the satellites, and for the human that would work on a possible aging time bomb).

This industry is starting with small steps, and will keep on going to more challenging mission.

RedStreak

Banned

From: Illinois

Registered: 2006-05-12

Posts: 541

Re: Space tug

What I heard regarding the CX is it is a tug designed to stabilize existing satellites in their orbits via ion propulsion.  Given the high fuel efficency this definetely extends satellite lifetimes which have usually only been cut short by running out of maneuvering fuel.

All it will do to dock, which has been the major stickler point since no commercial satellite has ever been designed for docking of any sort, is stick a probe into the empty fuel nozzle of the satellite in need and hold that position with the satellite above.

Its as simple a scheme as can be conceived so I route for the CX but I'd have to see what they could come up for future space tugs before casting any real opinions.