Servicing Iridium’s Satellite Constellation: Business Case (Part 2)–Background and Technical Challenges

Earlier this week, Colin Doughan posted the first post in what should hopefully be a fun series of posts on the business case of servicing the Iridium satellites over on his excellent Space Business Blog. As he mentioned at the start of the post, I’ve been working with him on this for some time, but ended up having to cut back on my involvement earlier this year when life began to get complicated… That said, I figured that some background on why we picked this problem might be useful, along with a quick discussion of some of the key technical challenges.


As I mentioned on my Space Show appearance earlier this week, my first appearance there in January ’07 elicited a lot of discussion both on the blog, and offline. I mentioned that a guy approached me with the question along the lines of “is there a way to wrap a business case around propellant depots”. That would be Colin.

We batted around a lot of ideas over the months, and came to the conclusion that while it was probably a bit too challenging to wrap a business case around depots directly. Not unless you had the backing of a wealthy philantrocapitalist like Musk, Bezos, or Bigelow (if any of the readers happens to be such a philantrocapitalist desperately in search of ways to invest a couple hundred $M to try and one-up Elon, my email address is, just in case you were wondering). The problem is that making depots really pay off probably requires at least two, and possibly three miracles. And when you have to raise outside money from non-philantrocapitalistic sources, you’re only allowed at most one miracle per business plan.

So, we backed up and looked to see if we could find any businesses that enabled depots that might be profitable in themselves. The idea of prox-ops tugs seemed to fit the bill. The idea is that one of the miracles needed for a depot is the development of a good prox-op tug that could take the complexity out of bringing “dumb” propellant tankers from their delivery orbit to the depot, hooking up the transfer lines, and then sending the tankers home empty when they’re done. If you could find a way to develop such a tug (or something close enough that it was clear that you only needed to trick-out your already existing tug with some slightly different add-ons), in a way that paid for itself, that would both make you some respectable amounts of money while simultaneously making the fielding of commercial depots that much closer to reality.

The challenge is that while there are probably a half dozen companies in the US that have the technical competence to design a tug-like spacecraft, and most of them want to do so pretty badly, none of them have really tried to go after this new market entrepreneurially. Now admittedly, and to be fair, it’s got to be really hard for a large, publicly traded company to take entrepreneurial risks like that in even the best of cases. But part of the problem has been the challenge of finding some initial toehold market that you can really get into the space tug business with.

There are a couple of aspects to this problem:

  1. You need a customer who has a need that’s bad enough they’d be willing to actually buy servicing from you.
  2. You need a technical approach that is non-scary enough that said customer will actually be willing to let you try
  3. You need a customer with money, and an approach that’s cheap enough that the value of your service to them is sufficiently less than your internal cost to develop and deliver that service that you can actually make money.

That’s a bit harder than it sounds, and at least part of the reason why nobody has actually delivered on orbital servicing using space tugs is that this is a tough nut to crack.

There are people out there who could probably benefit a lot form servicing (NRO and USAF LEO satellites, GEO comsats, etc), but their spacecraft are so expensive that they really don’t want to be the first guinea pig–second or third maybe, but they’d rather see you demonstrate your capabilities on someone else. In both cases we looked at options like just attaching the spacecraft and providing some extra maneuvering capability–not even trying to actually transfer fuel or power or anything. But the reality kept coming back to the fact that the amount of engineering work it would take to go directly after such a mission immediately would likely cost so much that you couldn’t raise the money. If you could demonstrate your capabilities on something easier first, it might be realistic to start servicing these bigger players, but that means you still need to find a toe-hold market. They’re great second markets, but not good toe-holds.

Iridium For The Win?

In the end, we started looking at the Iridium constellation, due to the collision they had with the Russian Cosmos satellite in February of 2009.

Colin hit on many of the reasons why Iridium looks like an interesting first customer for space tug servicing. But let me add a few more:

  • Iridium provides a large number of identical servicing targets.  Which means that you can design the servicing hardware once, and provide dozens of missions, reusing hardware, software, and experience.
  • Not only does losing satellites start cutting into Iridium’s ability to retain and grow their customer base, but satellite losses that turn into more debris could actually make it harder to successfully replace the current constellation.  They really need to keep those orbits clean enough that they can continue to use them.
  • While they really don’t want to lose many satellites, the fact that they do have some spares means that they can actually afford to take more risks on something like orbital servicing [Note: an article in Space News yesterday indicated that they felt they could still survive as a business if at least 36 of their satellites were still available when Iridium Next starts launching].  The bar is a lot lower than it would be with $1B NRO satellites, or GEO comsats that are bringing in hundreds of $M/yr/satellite.
  • The government has a huge interest both in Iridium continuing to exist, and in Iridium not having more of their satellites become collision targets.  At Iridium’s altitude and inclination, debris from any collision is going to increase the danger to just about all LEO orbits of interest.  Remember, unlike GEO where all the satellites are going in the same direction at nearly the same speed, LEO orbits all tend to cross each other.  It wouldn’t take too many repeats of the Cosmos collision to start really making a big mess.  So the government might have a legitimate reason to help try and encourage ventures like this.
  • With Iridium’s satellites getting old, the odds of one or more of them running out of propellant or having its batteries die before it can be disposed of is probably not insignificant.
  • The LEO environment is a lot easier to design an initial tug for, and a lot easier to affordably reach.  Not to mention you can probably get away with a smaller spacecraft.  All of these lower the amount of investment you need to raise up front.
  • Iridium actually has enough revenue that they might be able to afford a sufficiently low-cost servicing option.
  • Their only other option is really to count “hope” as an operating plan. The analysis I linked to above indicates that they think they can survive as-is, but having an orbital servicing option that allows them to continue at full capacity might still be very interesting to them.

What the NRO Doesnt Want to See a Repeat Of

What the NRO Doesn't Want to See a Repeat Of

How Best to Be Of Service?

So, we started looking at various options of servicing the Iridium satellites.  Our initial idea was to provide a small tug for each of the satellites.  If a debris conjunction appeared likely, or if the satellite’s attitude control system failed, or if the satellite ran out of propellant, the helper tug would take over, and either help the Iridium craft dodge the debris, or provide station keeping or end-of-life disposal services. While such an approach would eliminate the complexity of actually doing anything to the Iridium satellite other than just grabbing it, it would entail trying to make 66 small spacecraft cheap enough that you could launch them, hook them up, and perform their missions all for a price-point Iridium could afford…which quite frankly seemed unlikely.

We also looked at the idea of having only a handful of tugs (1-3) that would sit around in standby, and if an event came up, it would rapidly maneuver to the Iridium satellite in danger, rescue it, and then go back to standby mode.  While this cut down on the number of tugs you needed drastically, now the propulsion requirements goes way up.   Especially if you can’t put one in each orbital plane.  Switching from plane to plane requires a plane change if you have to do it in a hurry, and that can be crazy expensive from a delta-V standpoint (a 6o degree plane change done the quick way could cost you almost as much delta-V as it took to get into orbit).  You could also do ground based “rescue tugs” that could only launch on need…but once again none of these approaches was really realistic either from a launch frequency, propellant usage, or total cost standpoint.

What we finally settled-on was the idea of just refueling the satellites themselves.  If you did that, you could use one or maybe at most two or three tugs to do the whole job.  Plane changing between two planes with the same inclination can be done relatively cheaply if you have a lot of time.  You just go into either an elliptical orbit, or a circular orbit of different radius, and then your nodal regression rate will be either faster or slower than the Iridium satellite planes.  If you can be patient, you’ll eventually catch up with the next orbital plane.  Moving from satellite to satellite within a plane also requires some tricky maneuvers, but if you have time, they don’t have to use a lot of propellant.  One option we batted around was launching a little “mini-depot” (really mostly a dumb tank with some transfer systems and docking ports) into an elliptical orbit that would drift from plane to plane.  That way you wouldn’t have to accelerate and decelerate the whole propellant load each time you went into one of your drifting orbits.

The end result was that by doing it this way, you could cut down drastically on the number of launches, not have to be anywhere near as rushed, and cut down on the number of satellites.

For the paper one of the things we were going to do was analyze the different trajectories to figure out how much propellant it really took to move from satellite to satellite in a given plane (given various allowable travel times), as well as how much propellant it took to move between planes.  Once you know that, you can start getting a better handle on how many launches you would need, how long things would take, etc., which would start enabling you to get a realistic cost estimate for at least the marginal cost of the servicing.

Servicing Challenges

The one other big question mark was what it would take to service the satellites once you got to them.

An Iridium Satellite at the NASM
The Iridium satellites weren’t made for servicing.  The propellant inlets are capped with the caps safety-wired on.  And the whole assembly is likely covered up with MMOD protection or MLI.  I tried to get a good look at the one Iridium satellite they had up in the Air and Space Museum while we were out in DC for the NGLLC awards ceremony last year, but the area where I”m pretty sure the fueling interface was at was somewhere you couldn’t readily see.  I was sorely tempted to see if I could sneak up onto one of the displays nearby to get a peek, but chickened out. Anyhow, the net result is you’re going to need to do some stuff that would take about 15 seconds for a dude on the ground to do, but is going to be annoyingly complex to do on orbit.  I won’t go into details, just to avoid pissing off the ITAR gnomes, but suffice it to say this is not a trivial task.

There’s also the challenge that propellant isn’t the only thing that these satellites need.  Batteries and solar panels wear out.  While the latest and greatest solar panels are a lot better than what Iridium was launched with, you still need to find a way to couple that power into the satellite itself without hurting it.  Do you collect the power and then just beam it onto the other solar panels (might work if it’s just the solar panel efficiency that’s dropping)?  Or is there some sort of power umbilical used for the satellite on the launcher that could be reconnected to to provide both power, and a backup battery?  How do you attach it all?  Once again, I have some ideas, but I think I’ll leave things at that.

Real Life Getting in The Way

So, we had some starting ideas, and a basic approach.  We were still unsure if we actually wanted to jump on this idea as a real business, but we were interested in at least seeing where the analysis went. We pulled together a team to write the AIAA paper to investigate the idea.  I can’t remember for sure, but I think Colin was planning on using this paper as part of his MBA that he’s been working on.  And then life got messy and complicated, and in the end we had to back out of the paper.  But we wanted to put these thoughts up here to spur people’s thinking. If someone is going to provide this service for Iridium, the clock is ticking.  Even a fast-paced spacecraft development project is going to take probably 2-3 years, and there’s really not too much longer that you can delay and still be of use to Iridium.  Basically, we wanted to get the idea out into public to see if someone could find a way to run with it.

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Jonathan Goff

Jonathan Goff

President/CEO at Altius Space Machines
Jonathan Goff is a space technologist, inventor, and serial space entrepreneur who created the Selenian Boondocks blog. Jon was a co-founder of Masten Space Systems, and the founder and CEO of Altius Space Machines, a space robotics startup that he sold to Voyager Space in 2019. Jonathan is currently the Product Strategy Lead for the space station startup Gravitics. His family includes his wife, Tiffany, and five boys: Jarom (deceased), Jonathan, James, Peter, and Andrew. Jon has a BS in Manufacturing Engineering (1999) and an MS in Mechanical Engineering (2007) from Brigham Young University, and served an LDS proselytizing mission in Olongapo, Philippines from 2000-2002.
Jonathan Goff

About Jonathan Goff

Jonathan Goff is a space technologist, inventor, and serial space entrepreneur who created the Selenian Boondocks blog. Jon was a co-founder of Masten Space Systems, and the founder and CEO of Altius Space Machines, a space robotics startup that he sold to Voyager Space in 2019. Jonathan is currently the Product Strategy Lead for the space station startup Gravitics. His family includes his wife, Tiffany, and five boys: Jarom (deceased), Jonathan, James, Peter, and Andrew. Jon has a BS in Manufacturing Engineering (1999) and an MS in Mechanical Engineering (2007) from Brigham Young University, and served an LDS proselytizing mission in Olongapo, Philippines from 2000-2002.
This entry was posted in Air Force, Altius Space Machines, Business, Entrepreneurship, Propellant Depots, Tuggery. Bookmark the permalink.

43 Responses to Servicing Iridium’s Satellite Constellation: Business Case (Part 2)–Background and Technical Challenges

  1. Ian says:

    If you’re looking for a satellite to service that meets all your criteria, a good place to start would be the Satmex 5 GEO satellite operated by the Mexican satellite operator. I’ve always thought it made sense to pitch the idea to the hedge funds that own the Second Priority Notes.

  2. Ian says:

    As for Iridium, essentially all their cash flow for the next few years is going into capex for NEXT, even assuming significant revenue growth (which is what their financing strategy is predicated on). I don’t think Coface or any of Iridium’s creditors are going to take kindly to them engaging in a speculative servicing venture unless the servicing craft are built in France…

  3. john hare says:

    Quick thought on boosting solar panel capability is to have some clip on reflectors to increase the total sunlight hitting each existing panel. / <reflectors
    =========== < simple clip
    With all 66 targets the same, a stack of thin (Renolds Wrap thin)reflectors could be carried on each tug, and might boost available power enough to keep failing panel alive until the new constellatios are launched.

  4. ken anthony says:

    From time to time I imagine they will replace satellites. Wouldn’t that be the best time to upgrade the model to something that was designed to be serviced?

  5. Andrew S. Mooney says:

    An odd, late idea:
    If you wanted to demonstrate the utility of a prox-ops or space tug-type device, why not use it for station delivery of new satellites to the desired orbits? The last few hundred metres of delta-v are expensive and they could merit a separate vehilce to provide them. The accurate positioning of a satellite in a desired orbit is a precision burn, and normally, this then requires a one-use upper stage that is expensive in terms of quality control and is only useful once.
    By contrast, the inexpensive delivery of a set of satellites to a roughly accurate, eliptical orbit by a “dumb” booster is then assisted by a final burn from an orbital, upper stage that places each satellite into the desired orbit. It can do this one satellite at a time and returns to the delivery rocket and places the next satellite in position, and so on for each new one, it has saved serious money. This could even be a tactic employed to de-orbit each dead satellite into the atmosphere, making satellite disposal cheap as well.

    There is little point in trying to refuel or maintain satellites where the ability to refuel or maintain them was not built in. Stimulate the launch market by making launching more satellites into something that is cheaper….

  6. Mike Puckett says:

    Have you approached Irridum Jon?

  7. A_M_Swallow says:

    Have you found a bank that is willing to lend you the money against a payment on delivery/mile-stone contract?

  8. Ed Minchau says:

    I think the whole point of Jon posting this is for someone else with the time available to take the ball and run with it. The idea is too sketchy to take to a bank or even Iridium, yet.

    Precision final orbit placement via reusable tug instead of one-off upper stage has merit, Andrew. This is itself a potential propellant depot customer.

    If one wants a tug to be refueling existing satellites then you’re needing to tailor your refueling process to the LM-700 bus. If the target is the next generation of Iridium then they might build in refueling capability. The interface is key. It would be akin to the gas companies and the car companies over a century ago getting together to decide on a standard gas pump nozzle and matching gas tank inlet pipe.

    If the someone comes up with the interface and it gets used on the next generation of Iridium and refueling tugs, it becomes the default industry standard. Is it possible to do it Open Source?

  9. Ian,
    Interesting point about SatMex 5. Yeah life extension for a satellite with a failed Xenon thruster could be an interesting market. The challenge is that a) you have about two years to deliver the product, which isn’t impossible, but is challenging, and b) you probably need to find multiple targets to close a business case. Dennis Wingo has been trying to close the business case on orbital life extension for many years, without much apparent success. He may be doing something wrong, but he’s a smart enough guy that my takeaway is that it’ll be hard to break into that market directly. Now, if you could get a DARPA, AFRL, NRO, or NASA sponsored demo mission to help cover a lot of the development/tech maturation costs, then maybe you might be able to make it work. Hard, but possible.

    Regarding Iridium’s cashflow–that’s a valid concern. I wasn’t as familiar with Iridium’s financial situation as I was with their technical needs. Now, it might still be possible if you could make the clear case that the servicing, if successful, would provide a net increase in revenue (or at least prevent a decrease in revenue due to failing satellites). Also, I wasn’t so much assuming that Iridium would *fund* the development, so much as be a customer. If you pick their most likely to fail satellite (lowest fuel or weakest power system) as your first target, then the actual relative risk is low, and they don’t have to pay unless your servicing actually provides benefit…If Iridium didn’t have to pay unless it actually worked (ie no upfront development funding, just pay for a service) you think it might be easier to sell?


  10. John Hare,
    Clever idea. I still think they might want a way of providing backup to the battery itself (those tend to wear out over time), but that sounds like a clever way to augment the power levels they’re getting for their satellites. Not sure if they could actually take advantage of the extra power or not, but still a really clever idea. The thing I like the best about it, is that at least some of the panels are already mounted in what looks like a sun-tracking configuration (I’d have to verify that), which means that adding clipon reflectors like that could work really well.


  11. Ken Anthony,
    Iridium NEXT is the replacement. It *might* be possible to get them to design the satellites with servicing in mind, but only if there’s a credible servicing capability on the horizon soon… Also, unless ITAR reform moves a whole lot faster, it may be hard to coordinate with the European firm that’s building the Iridium NEXT satellites.


  12. Andrew Mooney,
    That’s an interesting idea. I’m not sure, but I think a lot of satellites have a limited amount of time they’re capable of surviving before being “turned on” in orbit. Might be a work-around to that, but that might be an issue. Also, depending on what orbit you’re looking at for a bird, getting a tug up and down might be pretty challenging, and/or expensive. For instance, I know that GEO is actually a hard nut to crack, since there aren’t many cheap ways of reducing the GEO back to GTO delta-V to something reasonable. But MEO or high LEOs might be more feasible for a tug. It is an interesting idea though, probably worth thinking about.


  13. Mike,
    No, I haven’t yet approached Iridium with this. Our plan was to coordinate with them on the paper, had it gone forward. But yeah, it might be worth touching bases with them now that I have a hook (pardon the pun) that might make such an idea feasible.


  14. AM,
    I’ll admit to not knowing a lot about bank financing. I had kind of assumed a strategy more of leveraging some small government funded demonstration contracts, and then going for angel investment. I’m not sure that banks would lend money to a speculative venture until someone had made something similar work.


  15. Ed,
    Well, the initial idea for posting this was as you suggested, but I may actually have a good way of getting involved in this market with Altius (that’s a blog post to come sometime soon), so another reason to get the idea out there was to see if there was enough interest that I could actually find a way to execute on a business idea like this.

    Regarding standardized prop transfer interfaces, that would be great. But in the near-term, it might be possible to find a way to take the existing Iridium fueling interface, and just make an adapter that goes from the existing interface to something better suited for refueling.


  16. Thanks everyone so far for the excellent questions/comments!

  17. Charles Miller says:


    As the former CEO of a venture (Constellation Services International, Inc.) who tried to close a business case for LEO satellite servicing in the 1998-2001 time frame, let me first welcome the posting of your thoughts.

    I do think there are a couple challenges here that have not been fully discussed yet, by you or others.

    First, Iridium almost certainly could not raise $1.8B in financing for Iridium Next — that they have raised — if that constellation depended on a non-existent and unproven servicing system to manage key constellation system and business risks.

    Even if you could convince Iridium management, their financiers would rightly balk as it would constitute a huge “if”. The easiest way to manage constellation system risks is to eliminate them by designing a system that does not need to be serviced. There are proven alternatives for risk management, which provide comfort to investors, and satellite servicing loses out (again and again) to these alternatives.

    The risks you are targeting with a satellite servicing system are mitigated in traditional ways — extra propellant, orbital spares, extra spares on ground (to backup the orbital spares), hardened subsystems, and more redundancy in systems in the s/c (to backup the hardened subsystems). These are well understood risk management techniques on spacecraft, which are acceptable to sophisticated and professional investors.

    We need to come up with a business reason — creating a MUST have reason for the satellite service that has low risk — in order for the businesses and their investors to “assume” such a high risk. Satellite servicing needs to be much better than alternatives, form both the business and investor perspective.

    Another issue — you mention that you want to sell a service to the Iridium management.

    Presuming you could convince Iridium that you had a great idea, it is almost certain that Iridium would insist on controlling development of the system. Controlling development is lower risk. Buying the service from an outside vendor — a startup company — is higher risk. This is why Elon insists on bringing all his subsystems in house, to the maximum extent practical. In my opinion, your best outcome (exit strategy) would be to be hired, and/or bought out, by Iridium.

    Third, we have a chicken and egg problem.

    As previously stated, satellite constellation system-level risks are currently mitigated in a variety of traditional ways — extra propellant, orbital spares, extra spares on ground, hardened more redundancy in systems in the s/c. Once the overall Iridium Next system is designed in this manner in order to manage risks, the actual value of a LEO servicing system on top of this to Iridium Next is very small. If a satellite fails, it is zero value to them to repair it, since the alternative (“use the backup already in orbit”) costs essentially nothing. If you assume a low probability scenario of many on-orbit failures, the system-level backup is to “launch already-built ground spares”. For this reason, the probability that a LEO constellation willingly signs a large contract for satellite servicing after their system has been designed and constructed with all this redundancy, becomes vanishingly small. Scenario planning starts looking at low probability events that only take place on a contingency basis, and only then if the satellite servicing system already exists and is proven. All of these factors make it difficult for a satellite servicing system to raise financing.

    A fourth issue — you state that this LEO servicing system would be used to target a secondary market from a propellant depot, with its primary use being as a tug to bring propellant into the depot. Good, as this helps address how you finance the satellite servicing system, but now it is tied to the inclination of the depot.

    What is the planned inclination of the Iridium Next constellation, and what is the value of a propellant depot in or near that inclination? (Most depots being considered for exploration purposes do not want to be in high inclination orbits.)

    NOTE: NASA has a “Commercial In-Space Servicing” working group that is looking at energizing, enabling and facilitating emerging commercial space capabilities. If anybody here would like to share their thoughts or ideas on commercial in-space servicing with NASA, including how the U.S. government might help industry overcome the hurdles to close a commercial business case, please contact me at charles dot miller at

    Onwards and upwards,

    – Charles

    Charles E. Miller
    NASA Senior Advisor for Commercial Space
    Office of the Chief Technologist

  18. Colin says:

    Iridium NEXT will cost ~$2.9B with ~$1B financed internally.

    I agree Iridium won’t have significant reserves to finance speculative risk reduction projects in the near term (with perhaps the exception of some event which threatens the viability of their current fleet prior to the launch of NEXT). But what if an entrepreneur uses Iridium’s satellite and not their money…?

    If Iridium’s current fleet *viability* is really 36 satellites, would they be open to serving as a guinea pig with one of their current sixty-six satellites (or several spares)?

    If mission funding was paid for by another (DARPA, etc.), Iridium’s risk profile for a servicing mission drops considerably. If the tug servicing is successful, Iridium is in a strong position to extend the life of a very valuable satellite constellation for far less than replacement sats could be launched from the ground (servicing for perhaps a few million $$ per satellite depending on hydrazine transfer volumes).

    Colin Doughan
    Space Business Blog

  19. Mark Martin says:

    As a space enthusiast I would like to add a couple of comments, hopefully they don’t sound too dumb ? Could there be a financial case for contracting a space tug to de-orbit the older generation of Iridium satellites given their age and risk of failure to de-orbit, as they could potentially clog up the orbital slots of the next generation of revenue earning satellites. If this could be done and seen to be reliable, more fuel could be set aside for revenue earning, leaving the tug to do the de-orbiting.

    Mark M

  20. googaw says:

    Let me suggest a very different direction for entering this business. There are dozens of recently derelict satellites out there that have been completely written off the books. You could buy them for pennies on the million dollars. Put another way, for a tiny extra fraction on top of your R&D budget you can buy fixable satellites for yourself.

    Once you’ve fixed the satellite and proven that you got it working again, you now have far easier sell to existing satellite operators than trying to sell a speculative service that could damage their reputation. One caveat is that most satellite designs are specific to a constellation, which is specific to an operator, so there is usually only one potential customer to sell them back to. Not as good a negotiating position as if competing operators were bidding.

    This approach will require a great deal homework to identify which specific derelicts could actually be most cheaply fixed with the technology you can most cheaply develop. If you avoid publicity about the relationship and can be trusted with confidential info the satellite operators will probably let you have the needed detailed specs. Quite possibly there exist a satellite or two where the fix is relatively quite easy. This homework is far more than offset by saving the high overhead costs of trying to convince skeptical operators to buy into your risky project. Now you just have to convince the philanthrocapitalist. 🙂

    Since the satellite operator is not involved, there’s no risk to the operator’s reputation should it crash and burn. All the risk goes on investors willing to take that risk and none to the ultimate customer.

    The first satellite should ideally be a very-easy-to-fix non-confidential derelict in LEO. Iridium, Globalstar, Orbcomm or similar may well provide such.

    BTW, if there’s more than one such investor, but they don’t have Musk/Bezos levels of funds, they could divide & conquer the business as follows. Some investors can buy potentially fixable satellites as a speculative investment. Others could invest in your servicing R&D. The speculators could then sell them to your company or subcontract out to your servicing company to fix them. The owner of a now working satellite would then sell it back to the satellite operator.

  21. googaw says:

    And now for a still different proposal. Several posters have suggested what businessfolk call vertical integration, for example making refuelable satellites in addition to making depots. Since, as Charles Martin points out, most of the risk that servicing schemes usually try to address are now addressed in the design of satellites and constellations themselves, (redundant hardware, hardening, spares, etc.), the biggest win from servicing probably comes from lowering satellite design and construction costs. But to win this savings requires vertical integration or at least an improbably codependent relationship between satellite builder and depot builder.

    Of course, for a typical constellation this would greatly increase the already scarce up-front investor dollars needed. For this to succeed and still have a reasonable budget one has to go very, very small. As in nanosatellites. And one has to discover a lucrative functionality for said satellites that would be much more difficult to do without servicing.

    The most lucrative such market will undoubtedly be NRO or NSA, but let me suggest a civilian version targeted at news organizations, financial investors, and other distributors or consumers of real-time information from space. About weather or disasters or similar. For example, our nanosats might have infrared telescopes to discover and analyze fires and this info could be sold to firefighters and insurance companies. Many possibilities here.

    Per a comment on Part 1 suggesting a “jerry can” approach to refueling, call it “Jerry Can Sat”. It’s basically hydrazine tank of a few tens of liters (call it 30) with a nanosatellite tacked on. The operational payload is 2-3 kg. Dry this Jerry Can Sat is about 10 kg, wet 40. One can fit about twenty wet on a Falcon 1 or Agena launched into a low polar orbit for a cost of about $600,00 to $1 million each.

    The key superiority of this constellation for the paying customer is that its satellites can be maneuvered from their starting polar orbit to polar orbits that fly over newsworthy hot spots in very little time. They start their lives launched with a big tank of gas, but it can’t be predicted when they will run out of gas. Thus, the need for a depot.

    The depot itself is simply yet another one of these maneuverable Jerry Can Sats, but modified to refuel other Jerry Can Sats. Indeed, perhaps one could even deploy a “peer-to-peer” scheme where any Jerry Can Sat can refuel any other one.

    Total launch cost $12-20 million, R&D and building the satellites and depot perhaps $100 million. So the revenue from the data customers has to be about $20 million a year to earn a goodly profit.

  22. Use liquid Argon and a Centaur derived vehicle as your tug,you are in need of the ULA proposed long term storage of cryogenics for this idea to come about.
    a flight experiment would be the Centaur and CRYOTE the in Kutter/2010 paper but with NEXT engines nestled in with the RL-10’s.Liquid Hydrogen boil off would refrigerate the liquid Argon.The sun shield would have photovoltaic cells sun word.

    The ULA proposed fuel tanker to L2 then would perform a secondary mission after fuel delivery utilizing ion or chemical propulsion or both.( oberth maneuver followed by long term thrusting)
    the secondary mission could be,
    earth flyby for a deep space mission
    Lunar communicatios relay
    L2 0r L1 satellite servicing with Liquid Helium( MR Kutter and I have been kicking around this idea)
    satellite disposal and servicing
    DOD…………..shssssss cant tell you! (DOD pays for the flight experiment!)
    NASA is planning two technology demonstrators, one for cryogenic fuel transfer and storage and another to test the ion NEXT engines.We should combine the two! Ad the Liquid Xenon or Argon to the flight experiment.The Proposed ULA Centuar CRYOTE could experiment with a tank of Liquid Noble’s and some NEXT engines.

    my business case,
    the ULA Fuel tanker to L2 makes economic sense if it also serves as a tug using Ion engines, and utilizing cryogenic Noble elements as fuel, and does so as a secondary mission to fuel delivery.the same vehicle delivers liquid helium to infer red space telescopes
    ( Kutter, Rappolee)

    questions and trades.
    could NEXT engines and Liquid LAr take the fuel tanker all of the way from LEO to L2? Or would the liquid Hydrogen losses be uneconomical?
    Can NEXT engines survive the RL-10 environment?
    what are the economics of a fuel tanker also serving as the tug?
    (A)deliver fuel (B)service mission (C)satellite disposal mission in that order.In that last mission the fuel tanker disposes it self.
    Does the secondary missions pay for our Dumb fuel tanker being converted into a sophisticated on orbit service vehicle?
    A fuel depot architecture with ion engine tanker/tug would produce a fleet of end of mission tankers, would this enable attractive pricing for subsequent servicing missions?
    Liquid Nobles, stored at Fuel depot?
    Does liquid nobles save on weight from pressurized tank?
    Does Liquid Nobles save on space?

  23. regulatory environment,
    after proving a in space fuel depot architecture, mandate that all DOD and civilian space craft be removed from Cis Lunar space.Operators would have 30 years after start of fuel depot operations to comply with satellite removal.This requirement kicks in only if the economics of a multiple mission L2 fuel tanker is realized.
    Another thought,
    Ion and chemical power make a perfect redundant system,chemical powers missions into and out of the Van Allen belts if required or for emergency zombie sat missions,ion power for the not in a hurry economy needed missions (Iridium) chemical for L2 earth slingshot deep space missions,then ion thrusting

  24. Paul says:

    Jon, (and other actual metal-benders),
    What do you see the tug actually looking like? As a mere aerospace-fanboi, of course I see some pop.sci cover art spider-bot, but I’m curious what absolute minimum requirements you see for the tug. Particularly if we’re talking about servicing sats that weren’t designed for it.

    Buying “junkers” to fix up and re-sell is a great business model once you’re set up, but it makes it hard to get that first investor. With the Iridium plan, if you can get a statement-of-intent agreeing to buy a service-at-a-price, you have something you can take to investors. They don’t have to take your word on the business model, Iridium’s done that for them, they only have to judge your business plan. It at least halves the difficulty of your “pitch”.

    After you’ve got that first tug operating, and earning money, then you can go back to investors and say, “We can take this proven capacity, apply it to these recently defunct sats, and re-sell for this price. But we need this amount to buy the first sat.” Again, you’ve halved your pitch.

    Steven, re:regulatory changes.
    Hey, if we’re wishing up legislation… It would be fairly cheap for the US Congress to pass a law requiring from 2015, all government funded satellites are to be launched empty and fuelled in orbit. Regardless of the contractor, regardless of the agency. If contractors are forced to build (re-)fuellables for NASA, NOAA, DoD, etc, it lowers the cost for commercial buyers to say “me too”.

    Investor angels, and ITAR devils:
    I wonder if it would be worth talking to the government of the United Arab Emirates about setting up the sat-service company there. If you’re doing development in the UAE, you’ve bypassed ITAR, and it means you can launch from (and sell to) any country without regard to US export restrictions.

    (It makes it hard to get high-end parts from the US, but I assume we’re adopting SpaceX’s in-house model.)

    Why the UAE? They’ve shown a willingness to invest petro-dollars in other industries long-term (in the hope of keeping the cash flowing after the petro-dollars dry up.) And they aren’t running to a two/four-year election cycle. And corruption and red-tape supposedly aren’t too bad.

    And you get to lay out the entire stepping-stone “wish list”, not just this first venture. “First we build a refueller tug, then depots, then look at asteroid-ISRU, then…” Because each stage, even if it fails to reach the next, is a win for the UAE in terms of tech-transfer, training, and national (and regional/racial) pride.

    Example: You send a probe to assay an asteroid for volatiles for ISRU. Even if nothing comes of it, it is still the first Arab deep space probe; one on a par with, perhaps exceeding, anything that leading nations have ever done.

    If they are anything like my own country, their local media bursts with pride every time they buy a new satellite. But this would be an Arab country building aerospace hardware in a unique world leading venture.

    (Contrast with the US, where half the industry/government sees a successful SpaceX launch as a national disgrace and/or personal insult. Contrast too nations like Iran, where they are building 1950’s launchers to play grown-ups.)

    And as an investment, you are selling an idea that seems inevitable. Someone, someday will refuel satellites. Someone, someday, will operate orbital depots. Someone, someday, will mine asteroids. “Why shouldn’t the pioneering technology, designs, patents, belong to your country, Your Highness?”

  25. googaw says:

    Paul, we’re not going to get agreement from Iridium or any other operator or builder of high-value constellations to commit major sums to or depend in any substantial way on such a risky and radically unorthodox (from their point of view) satellite lifecycle. An agreement to let us play with an otherwise useless spare perhaps. That’s about the same thing as my derelict satellite proposal but without the independent entrepreneur.

    They won’t make major commitments to such a project for reasons myself, Jon himself, Charles Miller and others have described. They’re already locked in to dealing with end-of-life unpredictability in other ways. And the idea that we’re going to force them into it by regulation is, as your satiric proposal points out, pathetic. Such threats are hardly a good way to win their sympathy. So we need either much more partial and gradual methods or a clean break (but on a very small scale to make it affordable).

    Alas, the NASA contractor culture that dominates space blogs has forgotten the entrepreneurial dictum that you have to start small. The first dam was a tiny diversion of a creek into an irrigation ditch. The first coal mine was just a little quarry. The first oil wells were built where oil was already seen oozing out of the ground and went down only a few feet. Facebook started with just Harvard. The Wright Brothers didn’t set out to build a Spruce Goose. Goddard started with rockets the size of his arm. The first orbital depots aren’t going to be monsters designed to take people to Mars (making a heroic astronaut’s life depend on such a seemingly dangerous operation as refueling is politically a hard sell, not to mention that such grand projects with or without depots are becoming less politically viable) nor is it going to revolutionize in one grand step a big constellation like Iridium. These are fine long-term dreams but they are not how the industry is going to start. Depots and servicing in general going to start very small, very simple, or both.

    Buying derelict satellites is a very easy step for a philanthrocapitalist. It doesn’t require the wealth of a Bezos or Musk or Bigelow, it can be done on a budget closer to a Carnack or Masten. For a small fraction of the cost of one Falcon 9 flight one could be the owner of several 99%-working satellites that, if fixed, could be worth a billion dollars. It’s a great speculative investment and even if it never works out it could be worth the publicity of being the first independent entrepreneur to make such an investment. Once that investment is made the credibility of the whole effort rises among investors, making finding investment for the actual servicing R&D much easier. To own a satellite is to have something concrete under your control, your destiny in your own hands, and that’s worth a million blog posts and sales calls in the hopes of convincing some strangers who are already strongly committed to a very different approach.

    To go the direction of building a serviceable constellation requires an extremely codependent relationship between the servicer and the satellite builder. Current satellite builders employ engineers and managers committed a very different approach to end-of-life risks as Charles described. So this approach requires control over the satellite design process itself — a clean break, vertical integration. Once again it pays to own the satellite yourself instead of trying to sell someone else already committed to a radically different approach.

    Further thought reveals that competing head-to-head with the current satellite lifecycle is not the best initial approach if our new, more flexible approach can deliver a better value to a sufficiently valuable segment of end customers, namely data transmitters, senders, or users. Value that the current inflexible satellite life cycle paradigm can’t satisfy. So don’t try to sell the idea in terms of depots and servicing. Start thinking of and selling the idea in terms of a radically different and far more flexible satellite life cycle. Servicing and especially depots provide a heretofore missing flexibility (a benefit which can be mathematically analyzed — Google “real options”).

    Thus my Jerry Can Sat proposal, where we vertically integrate (building serviceable satellites alongside the depots) and use (unpredictable amounts of) extra propellant to satisfy customer needs for data acquired at a particular time and place which a normal satellite stuck in a particular orbit couldn’t achieve (except by chance). All this done on a nanosatellite scale (except for the larger tanks) to make it affordable for early investors. The benefit here is especially compelling for NRO and NSA, but there are civilian desires as well that can’t be satisfied by the current inflexible satellite life cycle paradigm.

  26. googaw says:

    Here’s another way to think of the Jerry Can Sat: rather than a mere satellite, stuck in a particular orbit, it is a true spacecraft that can (within reason) change orbits on demand. For example starting from a polar or near-polar orbit it can do a small plane change to get it over its unpredictable intelligence, news, or evidence target far more quickly. To handle unpredictable operations, where we don’t know exactly where we want the instruments or relays to be at any given moment years in advance (i.e. to handle most real-world events), we benefit greatly from ditching the satellite and going to a true spacecraft. So, instead of nanosatellite think nanospacecraft: a big jerry can (or to save launcher shroud space perhaps even a “jerry bag”, using Bigelow/Transhab technology with a Teflon inner lining or similar as the tank) with a nanosat or microsat bus with payload instruments or relays attached.

    Besides giving spacecraft more ability to deal with unpredictable events, there’s another potential benefit of depots, suggested by the popular but economically fanciful gigalauncher vs. gigadepot debate. Namely, the capacity of a satellite launcher in terms of size, mass, or both often doesn’t quite match what the customer wants. Depots can potentially allow some customers to launch lighter weight satellites, either by launching them dry or with smaller tanks launched wet.

    This is for customers whose satellites built the current way would be a bit too large to fit on an affordable launcher, and they face economic or technological constraints that make it too expensive to shrink the actual payload. You save them for example $40 million on the launch by charging them $10 million for a fillup. There has to be a big difference between their savings and the service’s charge because of the risk involved, unless the service guarantees against the risk, which would actually be a good idea: e.g. the depot service pays for a replacement satellite and launch if the fillup goes awry (and you put that money in escrow): in that case you could charge $20-$30 million for the saved $40 million. Obviously not all (and probably not even most) satellite builders will have this logistical problem, but a few most years will, and your marketing and sales teams must discover them and sell them, preferably early in the satellite design cycle.

    An entrepreneur thinks about the benefits first and the tools second. Sell the benefits (the ability to deal with unpredictable events and discontinuous launch logistics) not the tools (servicing, depots, serviceable satellites, refeulable spacecraft, or variations on these). Then (re-)design the tools to best achieve the benefits.

  27. Paul says:

    “To go the direction of building a serviceable constellation”

    Ah. Here we may be arguing at cross porpoises. The original proposal, was to refuel the existing Iridium constellation. Designing sats that to be serviced, even nanosats, is much (much) further down the road.

    “regulation is, as your satiric proposal points out…”

    Satiric?! Why, sir, I’ll have you know I was and am always deathly serious!

    “we’re not going to get agreement from Iridium … to commit major sums to or depend in any substantial way on such a risky and radically unorthodox”

    Iridium is not investing in your business. They are a client. What you’d be asking for is a statement-of-intent. A soft pre-order. It’s a way of showing your investors that a client likes your idea and is willing to buy if you meet their requirements. It’s pretty common in business and uncontroversial.

    And that was my point. (And, I assumed, the reasoning behind Colin and Jon’s idea.) The business model would be easy to explain to Iridium. Their management is space-savvy enough to evaluate the service and put a price on it. However, as you say, it’s much harder to convince them to invest directly, to commit funds before you’ve flown anything harder than paper.

    Normal business investors, otoh, will not understand the business model, “I’m going to fix broken satellites with robots I build in my shed! Money please?” So instead you show them Iridium’s SoI, “We have a client willing to pay this much, this is our estimate of development costs, this is your investment plan.” It turns flaky off-the-wall speculation into a something no harder to analyse than a real-estate development. If you can do that, you are not relying on the seven people in the world who understand this stuff, instead you can appeal to any regular business investors.


    “Buying derelict satellites is a very easy step for a philanthrocapitalist.”

    …”you can’t get there from here.” Any idea that requires a space-savvy billionaire/multi-hectomillionaire speculator is no better than one that requires the government legislate you a market. I’m trying to imagine someone like Jon taking his company in this direction. Not Musk, nor Masten. Jon’d have to get find first-round investors who have perhaps never invested in a space venture before.

    tl;dr summary…

    A wealthy benefactor lets you skip three steps and jump straight to your final market. Without that, you need to do it the hard way, convincing normal people to invest. To do that, you need to prove to them that a market really exists. To do that…

  28. googaw says:

    Designing sats that to be serviced, even nanosats, is much (much) further down the road.

    We will have gas stations long before we have gas tanks designed to be topped up? Sorry, makes no sense. Making a gas tank refillable is far more straightforward than the added complexity and risk at a gas station if they have to puncture the gas tank, in a way not anticipated by the car designers, every time they do a fillup.

    BTW, the first gas tank was a slightly modified water container and the first gas station was a jerry can. Daydreams are wonderful but reality starts small and simple. An economic reality that NASA contractor culture with its taxpayer-fed gigahabits remains grossly ignorant of, alas.

    Iridium is not investing in your business. They are a client. What you’d be asking for is a statement-of-intent. A soft pre-order.

    It would be actually be safer for them to invest money than to declare that they have made themselves dependent on such a venture. In the first case only the money they invest in the new company is at risk. In the second case all the money that has been invested (and the further money they need to be invested) in their own company is at risk. Given to what happened to the last group of Iridium investors, it wouldn’t take too much to spook the current bunch.

    BTW, soft pre-orders are a dime-a-dozen. For the savvy investor they are no better than a mere press release. A dramatic nothing. Worse, soft orders are an uncertainty, a big question mark. Such a declaration of dependency would hurt Iridium with its investors more than it would help the service company with its investors. Iridium investors would discover a new risk whereas the risk to the service company’s investors would not be substantially reduced.

    Thus, Iridium is not going to declare that they are making themselves dependent on such a service, much less actually make themselves so dependent. Indeed, in a hypothetical world where Iridium’s need was so compelling and the depot service so low risk that they actually made a real deal, Iridium would insist that it be kept very confidential in order to avoid spooking its investors and customers. No one who can avoid it puts out a press release declaring that their product is broken and needs fixing. You would need their permission even to tell a handful of potential investors and confidentiality agreements with said investors. Hardly a great way to attract said investors.

    Normal business investors, otoh, will not understand the business model

    There are plenty of space-savvy people with money. The saner ones stay on the sidelines (or stick to conventional comsats) because 90% of the proposals they hear about on the Net or in the press come out of the NASA contractor community (including of course NewSpace) and 99% of those are preposterous economic fantasies, serving only as rhetoric to excite space fans and thereby get politicians, not investors, to cough up more money. But what is true for space-savvy people with money is even more true of the people at Iridium. You will have a hard time just getting in the door with the label “depot” because so much NASA-gigacontract-pursuing nonsense has been written about the topic.

    Assuming you passed that hurdle and got in the door, only reason they wouldn’t understand it is if the business model is in fact wrong (unfortunately this has been the case with the vast majority of depot proposals) or it hasn’t been explained it properly (also common alas). Oops, I guess you have a point. The proposals as they currently exist are a hard sell to any space-savvy investor, in most cases an impossible sale. But the case is again far worse with Iridium itself, whose management and engineers are even more space-savvy (e.g. their management instinctively knows the difference between NASA contractor rhetoric and real space commerce) and strongly committed to radically different ways to handle end-of-life risks.

    ”you can’t get there from here.” Any idea that requires a space-savvy billionaire/multi-hectomillionaire speculator….

    It requires a single-digit millionaire, at most. Perhaps even less than that. A handful of folks pooling a few tends of thousand each in an LLC would probably be sufficient. It’s called speculation. It’s something investors love to do, and again the only thing at risk here is the speculated money itself, not a much bigger pot tied up in a constellation designed the old fixed life-cycle way.

    BTW, for budding entrepreneurs I highly recommend Y Combinator’s Startup School. Here are some interesting recent presentations by successful entrepreneurs and investors:

    Angel investor and Sun cofounder Andy Bechtolscheim: discover the right problem and solve it the right way:

    Angel investor Reid Hoffman (PayPal, LinkedIn, etc.) on getting started small, failing fast, learning, pivoting, etc:

    Mark Zuckerberg, founder of Facebook on starting small and growing organically:

  29. Paul,
    I believe the senate two months ago mandated that future NASA astronomy satellites would have to be serviceable, a case in point would be the new The Astronomy and Astrophysics Decadal Survey that just came out from the national academy,they recommend a very large L2 space telescope. So here is a potential “customer” in the early 2020’s.
    Kutter of ULA and myself where kicking around the idea of a Liquid Helium transfer to astronomy satellites using a fuel depot architecture.
    but you are right the senate should have mandated the same for military satellites………………I believe Kutter et al have some precautions in there 2010 paper in regards to the fuel depot making economic since for DOD satellites.for example I do not believe there is an economic case for polar orbiting NOAA or DOD assets, Kutter et al did not mention these and it may be worth looking into……………
    perhaps mandating that government assets must be removed from the earth moon system by a fuel depot derived “tug” would drive economy’s of scale, the 2010 Kutter paper alludes to this but does explore further the idea
    I think this is key……………..future satellites yes, Iridium doubtful………….don’t think it will happen,but perhaps all of these thousand of defunct satellites do make a business case for a fuel depot tug,incorporate these satellites into a future ISRU system! this would a near far future where the spent tug on its last mission with its old KH-11 are “stored” some where for future ISRU
    so yes Paul,
    mandate 2015,grapple features on new space craft that are government procured,phase in serviceable features by law using a benchmark of,is fuel depot and a tanker/tug in development and at what rate?mandate for polar orbit but later and by the same bench mark,economic case for polar orbit fuel depot? mandate or not, or just a grapple feature for satellites below a certain orbit,IE LEO satellites are not a good economic case for ISRU, but and old tanker/tug could dispose of it self and a spent satellite below a certain orbit into the atmosphere.
    the post above(Googa) about collecting up mid orbit junk makes since as long as it is a end of fife mission for a fuel transfer and tug vehicle.spread costs, amortize over the lifetime of a tug……………

    I would like to know from Jon Goff what he thinks of hybrid Fuel depot tugs/tanker that use both chemical and Ion engines?could NEXT engines survive the environment of the Centaur’s RL-10 engine during operation?

  30. A_M_Swallow says:

    If a grapple feature is being added to satellites can it be combined with the connector to the launch vehicle?

    Combining the features may save mass and simply implementation by concentrating the modifications in a few areas.

  31. Douglas says:

    I’m just a fan, and not in the biz, but I was reading about the Zombie Satelite that broke down and came back on I was thinking along the lines of googa and Mark, but along slightly different lines.

    Yes you can service from a central space, maybe establish a tug at the ISS or a bigelow conastoga, with access to a depot (I know lots of parts, and a lot more stuff that I really have no clue about,I’m just riffing out as an ignorant observer) You don’t just have to find out which dead sattelites are worth repairing or maintaining. . .

    What about the value of being able to return the the satellites in whole once they shut down, for the purposes of research, while simultaneously replacing the satelites that are being removed?

    If NASA and other nations get around to setting up a space garbage removal/recycling fund, then that might be a good path for funding for a space tug.

    Pick the most tainted orbits, grab a place for the pilot to live for a while at a time, establish some kind of small scale shuttle (one already exists, the AF just flew one) release new, capture old, and the old can be examined for causes of failure other than electronics, which are almost always gonna fail.

    If you could get funding and volume, I think that everyone here already found a lot of ways of lobbying for research and funding for governmental/regulatory monies.

    Mine might be completely stupid, but I think markes and googa’s were good.

  32. nooneofconsequence says:

    The problem with participating with a constellation of comsats is that they already have considerable reason to mitigate risk with enough spares and financial structures to absorb losses in this manner that one does not provide enough of an advantage to compel interest straight up.

    Nor can one cope with unique markets of abandoned sats with a takeover, even assuming that one can “reanimate” them successfully, since the loss is already dealt with by existing means (insurance – please realize there are covenants and kinds of liabilities/tortes that certain legal theories could undercut such “rescues” long after the fact).

    My best guess here for a market is a hard one – “rescue” before write-down of a failed GTO insertion. You can get a value for fixing the problem and a frequency of occurrence, thus a TAM / market sizing / CAGR. Assuming one gets past the business case here, the issue would be gaining market acceptance – given that insurance companies might wish to improve loss ratios long term by this means. In the short term your help will always be viewed as a liability unfortunately. That is why you’d have to have one (better two) onboard as strategic partners, who have sold this as a way to make the business less chaotic. Not easy to do this.

    I would think the hard part of this business would be the cost of props in getting into an arbitrary capture orbit, plus the longevity needed of the craft between “rescues”.

    Orbital rescue is a tough business to enter – hardest being an extremely skeptical customer. Orbital life extension isn’t an entry market … but a likely follow-on to rescue, should you get that far. Orbital servicing would follow that as well.


  33. Paul says:

    Sorry, missed your message.

    “declare that they have made themselves dependent on such a venture. […] Such a declaration of dependency would hurt Iridium […] Iridium is not going to declare that they are making themselves dependent on such a service, much less actually make themselves so dependent.”

    You keep saying this. I tried to correct you in my last post, but you continue saying it, so now I’m paranoid I misread the original concept. Can you explain why Iridium would be “dependent” on the success of this venture?

    My reading of the original concept, especially SpaceBiz’s half, is that it’s aimed at Iridium’s existing satellites, the ones up there now. It’s to help them fill the gap between now and when their replacement “Next” fleet is ready. An optional “third back up” plan.

    So what am I missing?

    Designing sats that to be serviced, even nanosats, is much (much) further down the road.
    “We will have gas stations long before we have gas tanks designed to be topped up? Sorry, makes no sense. Making a gas tank refillable is far more straightforward…”

    Not when all the gas tanks are already in orbit. Whether it’s Iridium’s fleet or your idea of grabbing slightly broken sats. Again, unless I’ve completely misread Jon and Colin’s original concept.

  34. Paul says:

    </b> Sigh.

  35. noooneofconsequence,
    this is a great idea!
    I am sure it makes since, if it is a part of a broader customer base for a Tug/tanker/fuel depot architecture! having said that, one rescue mission, just one might, greatly amortize the worth and expense of a tug that has already performed a few servicing missions.
    your idea has traction,
    any multiple use on orbit of a component saves mass,I am thinking of LCROSS that used the Centaur avionics ring as a science payload, and the recent ULA paper that suggests using the EELV stage payload adapter as the housing for the Centaur cryogenic CRYOTE experiment.
    another thought, future tankers that use the payload fairing as part of their tanker walls just might add to my idea that orbital debris removal is in fact a future ISRU opportunity

  36. Paul says:

    When you guys are talking about “Debris removal”, should I read that as “Deorbiting spent upper stages” or “Chasing down stray bolts and paint chips.” The latter seems energetically… errr, difficult.

    Likewise, the US senate “mandating two months ago that future NASA astronomy satellites would have to be serviceable.” What did they mean by “Serviceable”, refuellable, parts-replaceable, or just fitted with grab-rails? Do you have a link to the actual language they used?

  37. Paul,
    let me find the senate language for you………..
    it does not state in detail what serviceable means, and it should not. (engineer design by congress may not be a good idea)
    my post above states that lower orbit junk should be de orbited, however higher orbit junk may be a future source of ISRU!
    regulate its removal in a responsible way
    store it some where for future retrieval for ISRU(L4)
    forget about the chips and paint 🙂
    but we should mitigate future chip and paint problems for future vehicles

  38. Pingback: Selenian Boondocks » Blog Archive » Light Blogging Hopefully Coming to an End (and 2010 review)

  39. Paul says:

    Here is another project that would benefit from serviceability.

    (Although their limit is probably more technological obsolescence. So its about upgrading electronics rather than refuelling. Easier/harder?)

  40. Paul says:

    Intelsat has apparently sighed up a Canadian company MDA Corp to do in-orbit refuelling of its fleet.

  41. Paul says:

    SpaceNews also has the response from Satellite manufacturers to Intelsat and MDA’s contract. Unanimously dismissive.

    Favourite comment: “Asked what Orbital might do to prepare its satellites for in-orbit servicing, [David W.] Thompson [chief executive of Orbital Sciences] joked: “We’d probably weld that fuel cap on.” Nice bastards.

  42. Regarding the caption on the diagram of the earth with the satellite orbits: What the doesn’t the NRO want to see a repeat of?

  43. Jonathan Goff Jonathan Goff says:

    I think what I meant was that they wanted to avoid another collision in a relatively high LEO orbit that sprays debris all over the place.


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