[X] My Assistant

[karolp]

So, in the 1960s we did it like that:

1. sending single, big spacecraft of very limited, one purpose capability and limited lifespan
2. not being able to re-use the spacecraft for other targets
3. no means of controlling the situation when something goes wrong at landing etc.
4. not being able to see the spacecraft from orbit
5. designing each spacecraft from scratch instead of reusing and further developing existing designs

All in all, this resulted in:

A. a lot of failed missions and wasted money and effort
B. only limited scientific results which usually required follow-up missions which still were inconclusive
C. very expensive missions that took years to develop and perished in seconds if something went wrong

We may have made some progress in some points with missions like MRO which can see ground spacecraft from orbit or even take snapshots of spacecraft landing in progress (Phoenix). However, this is still occasional "byproduct" and not a change in philosophy. Therefore, I'd like to suggest creating a more general thread about the specific issues listed in the first paragraph.

Let's face it, we still do relatively expensive planetary probes which still provide us only with limited "beachhead" kind of scientific results and do not have a lot of maneuvering capability nor planning flexibility.

Here are a few suggestions which I would love to see discussed by people who know more than me about space exploration technology:

1. first and foremost: no more single, big and expensive, heavy spacecraft

Instead of taking one big rover on board, we could take one small rover, one small airplane and a cluster of microbots designed for specific purposes - each providing valuable data in many areas simultanously and if one is dead, there are still plenty of others to continue the mission.

2. a spececraft already there is better than one on the drawing board

No more short lifespans. Each mission should be designed while keeping in mind that money for future missions and follow-ups may not be available. Accumulating a lot of data over a lot of time gives us insight into how things CHANGE over time on a given target.

3. no more fly-by expendable spacecraft

Flying by a planet to see what it looks like and letting the spacecraft then fly into oblivion may have been a good idea back in the early days but not any more. I tend to regard this kind of approach as extremely short-sighted, providing only short-term gains which do not balance the cost and effort involved. I think we need spacecraft that is finally able to MANEUVER itself, meaning it has its own propulsion of some kind, be it only a weak ion thruster.

This way we could actually GO PLACES rather than select one target and writing off an entire spacecraft after this target is examined. Reusing Stardust and Deep Impact were good examples of this approach. However, I think this should be a default capability of every spacecraft rather than counting on pure luck and coincidence in selecting additional targets.

Imagine the Voyagers being able to come back to their previous targets or Galileo setting itself free of Jupiter's gravity and going out to explore asteroids instead of plunging into its fiery demise.

4. no more single-spacecraft "hope it works" approach

Instead of sending just one orbiter or one lander, we should send a lander and an orbiter simultanously so that we have the possibility of tracking spacecraft as it lands and inspecting it afterwards. No more "lost spacecraft stuck somewhere". We could aim at making spaceraft COOPERATE not by coincidence but from the start.

Let me give you a nice example: imagine we might send a new orbiter and a new lander to Titan. Obviously the orbiter will provide data link capability and some basic radio tracking. But would it not be wiser to actually fit it with a decent camera that allows it to actually SEE the spaceraft if something goes wrong?

I shall go into more detail on that in another thread:

http://www.unmannedspaceflight.com/index.php?showtopic=5820

Do not worry, I won't fill the forums with lots of my threads of this kind, just this one and another one for some of the things that had been on my mind for some time now.

And finally:

5. no more reinventing the wheel each time we go somewhere

Of course each mission has its specific goals, but modifying an existing design might actually be cheaper in a lot of cases. And most of all: there is nothing wrong in sending identical spacecraft to two different asteroids

[dvandorn]

A few general replies:

- We may not re-use a lot of hardware designs, but we re-use information, and that saves a lot more money than you might think. For example, the Viking program ran hundreds of millions of dollars' worth of tests on its entry vehicle shape and dynamics, and of its parachute system. Every successful landing on Mars since then has re-used the Viking developmental data, thus saving hundreds of millions of dollars in developmental testing.

- You can design a general spacecraft bus for destinations with similar environmental characteristics, true. But how many destinations have similar environments? The Moon is unique in terms of thermal environment, as are each of the rocky planets. Vacuum operations are the same on the Moon and on asteroids, but there are large differences in how much you can rely on gravity between the Moon and an asteroid -- gravity not only helps you move around (it keeps your wheels in contact with the ground), it also keeps your lander from flying off the surface if you use, say, a pneumatic drill or a rock chipper. Also, power systems must differ drastically depending on periodicity of insolation, degree of insolation, etc., and that's just when you're using solar power.

- Again, if you're going to find the money needed to launch a fleet of probes, then yes, it makes sense to make a bunch of the same probe and send them all over a period of a year or three. That was proven in the American lunar probes of the 60s. But a fleet of probes means a fleet of launch vehicles, and launch vehicles are the most expensive single part of the equation. You want to send five probes using Atlas V or Delta IV as launch vehicles? Then you need to add at least a half a billion dollars to your budget, just for the launch vehicles. Even if Falcon 9 works the first time and every time and you can buy one for only $50 million as opposed to the $100 million for an Atlas V, then your five probes still require a quarter of a billion dollars for launchers. And, it can be asked, why did you need to have five probes when one could have given you 90% or more of the data returned by all five?

- You seem to think that ion propulsion is the overlooked savior of sending huge probes all over the solar system cheaply. The only reason the existing ion engines have been successful in sending small probes around a variety of locations is that they are very low thrust engines, and thus require a relatively small reaction mass. (Ion engines work like any other rocket engine in that they expel mass out of a nozzle to make the spacecraft go the other way, so your total amount of delta-V is limited by the reaction mass you can carry with you.) Ion engines are low-thrust affairs, it's not just a matter of "Hey, let's scale this up and make ourselves a big, powerful ion engine that still only needs a couple of hundred kg of fuel to go from here to Mars!" That violates the physics of how ion engines work; if you want big, powerful engines, you really need to carry a lot of reaction mass, whether you use chemical, nuclear or electrical energy to force that mass out of a nozzle. There's no current way around that.

- You say we've spent all this money but not made any real progress on understanding Mars. I beg to disagree. We have a tremendously greater understanding of Mars than we did even 10 years ago. Yes, we don't understand entirely what might be happening in terms of life on Mars, but we *do* understand that life is not widespread, that if it exists it evades detection sensors that would detect even a devastated ecology, and that if it does exist, it must be hiding in places so well-protected from inimical factors that it will be difficult to well-nigh impossible for easily-affordable probes to find and study. I'd say that's an understanding several orders of magnitude more sophisticated than we had when we launched Mariner IV 35 years ago, and that understanding has been refined by only six successful landers and nine or ten orbiters (depending on how you classify some of the Soviet orbiters in terms of adding to our information). Just because they haven't found what you wanted them to find doesn't mean that these spacecraft have made no progress. They've not found what we were looking for in all cases, true -- but, far more importantly, they've found what is there.

- The MERs are fitted out with the best AI we've been able to design, in terms of what AI is useful for on a MER-like mission. The girls have even gotten smarter as the missions have progressed, thanks to upgrades to their AI-like autonavigation capabilities. That's what AI is right now, and the MERs have it. And as Dan asked, in what way does AI enhance your mission? Does it make it cheaper? If so, how? I don't care how good I think I have made an AI, I'd want to monitor it, improve it, and make sure it doesn't do something stupid pretty much constantly. There is literally no way to make AI any better than it is right now; increases in computer power and the subtlety of programming languages has not brought us nearer to, say, allowing AI routines to run our cars or our air traffic control networks. It would have to get at *least* that good in order to be useful on a space probe, right? And, trust me, the economic advantages of AI that can run air traffic control, or drive you car, are such that those types of applications are already driving AI development. This isn't a case where you can develop AI for your favorite Titan lander and then make up the trillions of dollars you need for your exploration plans by selling your AI to the car companies -- you are *much* more likely to adapt whatever AI DARPA, or the airline industry, or the car companies come out with for your space probe, and consequently will need to find the trillions of dollars you need for your exploration plan somewhere else.

-the other Doug