Apr23
Another Unfortunate Document Leak
on April 23, 2012 at 11:52 amIf you’re an SLS supporter, that is. Spaceref has a NASA document from November that concludes utilizing orbital assembly and fueling for exploration missions adds no significant mission risk. Opponents of this concept have been sowing FUD (fear, uncertainty and doubt) about this ever since it became viewed as a threat to first Ares, and now SLS. It was always a monumentally ignorant argument, that could be made only by someone unfamiliar with basic statistics and space ops (and sadly, it was once even made by the administrator himself), but now NASA has an internal document that shows what nonsense it is (and really, always was). Of course, in defense of Bolden, he knew what his audience wanted to hear.
Ok. There is some additional risk because any activity carries additional risk. Like filling my car with gas. We seem to find that acceptable even those cars kill a lot of people even after they leave the gas station.
How can anybody reasonably argue against fuel depots or fuel transfer?
“Ok. There is some additional risk because any activity carries additional risk. Like filling my car with gas. We seem to find that acceptable even those cars kill a lot of people even after they leave the gas station.
How can anybody reasonably argue against fuel depots or fuel transfer?”
I can argue against depots as I can against lunar mining. NASA could spend far too money and time with fuel depots.
NASA focus should on using fuel depots as much as possible. The focus should working with the private sector. The focus could be for NASA to develop prototype depots.
But if depots are not markets of rocket fuel in space, but instead government assets to be used solely by the government, then one still has some value to such depots, but quite possible that over time such operation with eat away at NASA budget- it not hard to imagine NASA getting to the point of spending as much or more on fuel depots as it currently spends on ISS.
Same problem with lunar mining- NASA could bog down in operations [trying lower cost or whatever] and end up spending hundreds of billion of tax payer dollar competing with [though more like shutting out] the private sector.
It would also be nice, if the rocket fuel market was allowed to be international opposed to attempting to make it domestic.
Of course the document is filled with caveats and “but on the other hands” that make it useless as a means to support depots over heavy lift.
Like this, for example:
“End Loss of Mission (LOM) and Loss of Crew (LOC) risks
- There are still many unknowns such as actual reliability of future propellant transfer
- Analysis results are very preliminary with both positive and negative effects that have not been fully quantified at the present time and will depend on actual implementation”
In other words, the study cannot state with any real certainty of the risks involved.
Obviously the numbers will be refined with operational experience, but what part of “This study does not support the perception that depots add an unacceptable level of risk and should not be considered due to the increased number of launches, AR&Ds, and transfers” do you not understand?
There are still many unknowns such as actual reliability of future propellant transfer
Not decisive because we could start with past and present propellant transfer.
– There are still many unknowns such as actual reliability of future propellant transfer
And you expect SLS to be 100% reliable?
>There are still many unknowns such as actual reliability of future propellant transfer
Taken to its logical end point, wouldn’t this argument preclude doing anything for the first time, ever? Logically the only way to discover the actual reliability of propellant transfer in orbit is to transfer some propellant, while in orbit…
Are you conceding that HLV supporters cannot state with any real certainty that HLV is less risky?
Noted.
Addendum. Besides, can you imagine taking this document with contradictory statements to someone like — say — Mitt without any numbers or hard data to support it and asking him to approve a change of direction? Believe me his space brain trust is almost certainly giving him numbers supporting heavy lift.
Mitt is not paying any attention to his “space brain trust.” He doesn’t care about space, and won’t until after the election, and then not much. Eric Anderson is also part of his “space brain trust,” to the degree that it exists. He is going to have to confront a budget reality. SLS is unaffordable and unneeded, and it won’t survive.
Mark, there are no “numbers” that support heavy lift. Guesses and estimates maybe, but no real numbers.
And if Romney is the business genius he is supposed to be, then he’ll ask “who are the customers that will be using the SLS” and “what problems does the SLS solve”? When the answers come back, and they are both “None”, then Mr. Business President will cancel the program and book the savings for budget reductions.
The Senate created the SLS to save jobs that were destined to end with the cancellation of Constellation. No potential users of the SLS have ever shown they have the money to use it, and no one has ever shown there are enough missions to justify it’s use. NASA can’t even afford to use it, what with SLS missions costing $10B or more to build, and 10 years to get ready.
Fuel depots are one of the gating items keeping up from continuously operating beyond LEO – every reusable architecture requires the ability to refuel in space. So the longer we spend money on something we don’t need (i.e the SLS), the longer it will take us to venture permanently beyond LEO.
I’m in favor of depots and the benefits that they can bring about.
However, a rational argument against them would go like this:
* Initial mission design would include several different/redundant tankers to the depot, and several redundant depots, and several redundant “spaceships”.
* Budget cuts and cost overruns will lead naive management into cutting redundancies.
* the final mission will have single points of failure in the depot, tankers, and no extra margin to handle failure due to the cuts. Furthermore, the complexity of the mission will be greater than that of a single launch mission, leading to increased failure rates.
* Ergo, we should not do depot based missions because they won’t turn out to have abundant margins and redundancy ( although any rational design would cheaply include this).
That “argument” might make sense if there were redundancy in the heavy lifter whose proponents claim we cannot live without.
Not really. We don’t need dedicated depots straight away, spacecraft capable of taking on propellant in orbit would be enough. That would require a slightly more sophisticated spacecraft (though still using only very mature technology), but allows you to dispense with the enormously complex and expensive HLV. That would mean a net reduction in complexity as well as a far more flexible and more capable system.
Need is an interesting word there. It has been argued we don’t need to be in space at all. The thing about fuel depots is they enhance capability regardless of the capability we start with in addition to making things possible that otherwise are not. This is what makes them a no brainer… but we don’t actually need them (until we do.)
Since a depot based architecture naturally has many pieces, perhaps the way to “sell” this is to have tanker type 1 built in TX, tanker type 2 built in UT, depot #1 in CA, depot #2 in KS.
Oink, Oink, Oink.
The argument for fuel depots is mush more compelling.
1/ With any type of architecture without fuel depots (SLS) you use things once and throw them away.
2/ With fuel depots you introduce reusability. Reusing things over and over reduces costs.
3/ Fuel depots allow you to extend your range. Fill up your tank and away you go again.
4/ Fuel depots allow you to simplify and standardize your designs. You no longer need to tailor your vehicles exactly to each mission. If a mission requires more than your basic vehicles are capable of just add another fuel depot along the way. Stop. Fill up. Go on.
All this adds up to cheaper space travel, and without that we are going nowhere in space.
I heard this quote today and suddenly the last 40 years of NASA history made so much more sense:
“In the absence of clearly-defined goals, we become strangely loyal to performing daily trivia until ultimately we become enslaved by it.”
― Robert A. Heinlein
As a thought experiment, imagine driving your car from coast to coast if there were no gas stations. You would have to carry all the fuel you need at the start of your trip. So you’d need a car with an enormous gas tank, or else tow a series of trailers full of gas, discarding them along the way. Either way, your car’s engine would need to be powerful enough to pull all that weight. Which would consume even more fuel. Late in the trip, your engine would be much more powerful than necessary to pull the reduced load.
Fuel depots sound like a no-brainer to me.
Unfortunately, “no brainer” accurately describes many of the people who oppose this. The rest are just protecting their phony baloney jobs.
We don’t need to argue for them because they are self evident. We need to argue for its precursor to get things moving. That would be a cislunar ship capable of fuel transfer in both directions.
Put that in orbit and you have a market for fuel delivery. Get a market for fuel delivery and depots don’t need any more argument.
If they could get the flight rate of SLS up to like 6 flights per year (the sweet spot for the Shuttle flight rate) and its primary job was hauling propellants for a depot system, it would fit hand and glove with a depot-based architecture. So heavy lift and depots are not necessarily mutually exclusive.
But the current talk is that the production facilities will only be able to crank out one SLS every other year. Clearly unacceptable, and if that’s the best they are going to be able to do with the present budget, it’s clearly time to cut our losses and run.
clearly time
Came and went a long time ago. Now it’s just an example of our dysfunctional government.